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Journal Cover   The Knee
  [SJR: 1.137]   [H-I: 44]   [14 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0968-0160
   Published by Elsevier Homepage  [2800 journals]
  • Analysis of risk factors for poor prognosis in conservatively managed
           early-stage spontaneous osteonecrosis of the knee
    • Abstract: Publication date: Available online 25 August 2015
      Source:The Knee
      Author(s): Hiroshi Nakayama, Tomoya Iseki, Ryo Kanto, Takashi Daimon, Kaori Kashiwa, Shinichi Yoshiya
      Background Management guidelines for early-stage spontaneous osteonecrosis of the knee (SONK) have not been established. The purposes of this study were to review the outcome of conservative treatment for patients with early-stage SONK and to examine clinical factors affecting the prognosis. Methods Diagnosis of early-stage SONK was made based on the criteria consisting of specific clinical features including magnetic resonance imaging (MRI) findings. During the study period, all patients with this diagnosis underwent standardized conservative treatment. The study population comprised 38 knees in 36 patients with a mean age at presentation of 66.4years. The mean follow-up period was 34.9months. During the treatment course, progressive joint space narrowing or collapse of bony contours identified in serial follow-up radiographs was regarded as indicating a poor prognosis. The significance of potential prognostic factors such as age, gender, obesity, coronal alignment, lesion size, and MRI findings was analyzed using a multivariate logistic regression analysis. Results The prognosis was defined to be poor in eight knees (21.1%). The multivariate logistic regression analysis for potential risk factors revealed that only varus alignment with a femorotibial angle (FTA) of 180° or more on the initial radiograph was significantly associated with the poor prognosis (P =0.01, odds ratio 28.1) while no other factors significantly correlated with the prognosis. Conclusions Approximately 80% of patients with early-stage SONK could be managed successfully with conservative treatment without progression of the disease process. The presence of varus deformity (FTA of 180° or more) was significantly associated with poor prognosis complicated with progressive deformity and prolonged disability. Level of evidence Level IV, case series.


      PubDate: 2015-08-29T05:34:38Z
       
  • Patient-specific implants with custom cutting blocks better approximate
           natural knee kinematics than standard TKA without custom cutting blocks
    • Abstract: Publication date: Available online 29 August 2015
      Source:The Knee
      Author(s): Shantanu Patil, Adam Bunn, William D. Bugbee, Clifford W. Colwell, Darryl D. D'Lima
      Background Nearly 14% to 39% TKA patients report dissatisfaction causing incomplete return of function. We proposed that the kinematics of knees implanted with patient-specific prostheses using patient-specific cutting guides would be closer to normal. Methods Eighteen matched cadaver lower limbs were randomly assigned to two groups: group A was implanted with patient-specific implants using patient-specific cutting guides; group B, the contralateral knee, was implanted with a standard design using intramedullary alignment cutting guides. Knee kinematics were measured on a dynamic closed-kinetic-chain Oxford knee rig, simulating a deep knee bend and in a passive rig testing varus–valgus laxity. Results The difference from normal kinematics was lower for group A compared to group B for active femoral rollback, active tibiofemoral adduction, and for passive varus–valgus laxity. Conclusions Our results support the hypothesis that knees with patient-specific implants generate kinematics more closely resembling normal knee kinematics than standard knee designs. Clinical Relevance Restoring normal kinematics may improve function and patient satisfaction after total knee arthroplasty.


      PubDate: 2015-08-29T05:34:38Z
       
  • Influence of anterior cruciate ligament rupture on secondary damage to
           menisci and articular cartilage
    • Abstract: Publication date: Available online 19 August 2015
      Source:The Knee
      Author(s): Fei Yan, Feng Xie, Xiaoyuan Gong, Fuyou Wang, Liu Yang
      Objective To evaluate the influence of anterior cruciate ligament (ACL) rupture on secondary damage to menisci and articular cartilage. Method A total of 366 patients with knee ACL rupture were divided into six groups according to the time span from the initial injury to ACL reconstruction: (a) less than 1.5months, (b) between 1.5 and three months, (c) between three and six months, d) between six and 12months, (e) between 12 and 24months, and (f) more than 24months. During ACL reconstruction, impairment of meniscal or chondral integrity was systematically documented. Results Among these 366 patients, meniscal damage was found in 223 patients (60.9%); and chondral damage was found in 75 patients (20.5%). In addition, the incidence of medial meniscal and chondral damage was significantly increased with longer time span from the initial injury to ACL reconstruction. We found that the incidence for medial meniscal and that for chondral damages were 6.1 and 9.9 times higher in patients with a time from initial injury (TFI)>24months than those in patients with a TFI<1.5months, respectively. Conclusion In the present study, correlations between secondary damages to the menisci and/or the articular cartilage and time post initial injury were found in Chinese population. Our data suggested that ACL reconstruction operation should be done as early as possible after ACL rupture to avoid secondary meniscal and/or chondral damage. We recommend that the best time range for ACL reconstruction is between four and six weeks post initial injury. Clinical relevance:


      PubDate: 2015-08-21T04:33:12Z
       
  • Minimally invasive medial patellofemoral ligament reconstruction for
           patellar instability using an artificial ligament: A two year follow-up
    • Abstract: Publication date: Available online 12 August 2015
      Source:The Knee
      Author(s): Aditya Khemka, Sarah J. Lord, Zelda Doyle, Belinda Bosley, Munjed Al Muderis
      Background Recurrence of acute patellar dislocation affects approximately 30% of individuals, and up to 75% of those with grade IV instability. The medial patellofemoral ligament (MPFL) is considered to be critical for patellar stabilization. MPFL reconstruction with allografts has been proposed to reduce risk of recurrence, but there is limited evidence about the safety and effectiveness of techniques using synthetic allografts. Methods We present a retrospective case series of 29 individuals who underwent a MPFL reconstruction between 2009 and 2012, using an artificial ligament for patellar instability by a single surgeon. Clinical, radiological and functional outcomes were measured at a minimum of 24months. Results 31 knees (29 individuals) were followed up for a median of 43 (range: 24–68) months. Using the Crosby and Insall grading system, 21 (68%) were graded as excellent, nine (29%) were good, one (3%) as fair and none as worse at 24months. The mean improvement in Lysholm knee score for knee instability was 68 points (standard deviation 10). Ligamentous laxity was seen in 17 (55%) of individuals. In this subset, 12 were graded as excellent, four as good and one as fair. The mean improvement in patellar height was 11% at three months follow-up. All knees had a stable graft fixation with one re-dislocation following trauma. Conclusions We propose a minimally invasive technique to reconstruct the MPFL using an artificial ligament allowing early mobilization without bracing. This study indicates the procedure is safe, with a low risk of re-dislocation in all grades of instability. Level of Evidence Level IV Case Series


      PubDate: 2015-08-17T03:59:31Z
       
  • Lack of agreement between computer navigation and post-operative
           2-dimensional computed tomography (CT) measurements for component and limb
           alignment in total knee arthroplasty (TKA)
    • Abstract: Publication date: Available online 15 August 2015
      Source:The Knee
      Author(s): Ziad Dahabreh, Corey J. Scholes, Bruno Giuffre, Myles R.J. Coolican, David A. Parker
      Background The purpose of this study was to assess the degree of mismatch between intraoperative navigation data using imageless computer navigation and post-operative CT scan measurements with respect to bone cuts, component and limb alignment during TKA. Methods Intraoperative navigation data including bone cut verification and overall limb alignment during TKA was compared to postoperative CT measurements of component and limb alignment according to the Perth protocol. The proportion of cases with mismatch between navigation and CT measurements at two and three degree thresholds was identified. Results In a total sample of 50 primary TKAs, 20% of cases showed a mismatch of more than two degrees between navigation and CT obtained measurements for coronal femoral alignment, 42% for femoral rotation, 16% for tibial component coronal alignment and 32% for overall limb alignment. Conclusion Mismatch between intraoperative navigation data and postoperative CT measurements suggests that postoperative CT scan alignment data should be interpreted with caution. A surgeon should consider a multitude of factors when analysing component and limb alignment postoperatively.


      PubDate: 2015-08-17T03:59:31Z
       
  • The triangle zone as a femoral attachment location in medial
           patellofemoral ligament reconstruction: An in vivo three-dimensional
           analysis using an open MRI scanner
    • Abstract: Publication date: Available online 14 August 2015
      Source:The Knee
      Author(s): Ning Zhang, Zhengang Jiang, Xiaoyu Wen, Kazuomi Sugamoto, Chen Yang
      Background The exact isometric points for medial patellofemoral ligament (MPFL) fixation during MPFL reconstruction remain a matter of debate. Purpose The aim of this study was to characterize the functional length changes of various patellar and femoral fixation sites using in vivo three-dimensional (3D) movement patterns and to determine the ideal fixation sites at which the graft remains largely isometric. Methods Twelve right knees of healthy volunteers were examined at early flexion angles (0°, 10°, 20°, 30°, 40°, 50°, and 60°) with a horizontal-type open magnetic resonance scanner, and 3D models were reconstructed using the marching cubes algorithm. Six points on the femoral condyle and three points on the medial aspect of the patella were simulated. The matching points represented the MPFL, which crossed the bony obstacle. The MPFL length changes were analyzed at various flexion degrees. Results The lengths from the dome of Blumensaat's line (G), the point 10mm inferior to the adductor tubercle (H), to the midpoint between the adductor tubercle and the medial epicondyle (I) were more isometric than other points. The lengths between the dome of Blumensaat's line and the superior pole of the patella changes significantly between 20° and 60° of flexion (p =0.040). Conclusions The femoral fixation site may be more accurately located during MPFL reconstruction at the G, H, and I points to restore the native biomechanical function of the MPFL. The dome of Blumensaat's line should be avoided during MPFL reconstruction with the superficial quad technique. Clinical relevance A triangular region composed of the dome of Blumensaat's line, 10mm inferior to the adductor tubercle, and the midpoint between the adductor tubercle and medial epicondyle is recommended as the femoral fixation site.


      PubDate: 2015-08-17T03:59:31Z
       
  • Factors associated with a more rapid recovery after anterior cruciate
           ligament reconstruction using multivariate analysis
    • Abstract: Publication date: Available online 8 August 2015
      Source:The Knee
      Author(s): Job E. Scherer, Maarten H. Moen, Adam Weir, Sandor L. Schmikli, Rob Tamminga, Henk van der Hoeven
      Background In the past, several studies investigated factors that are prognostic or associated with outcome after anterior cruciate ligament (ACL) reconstruction. A recent review showed that only limited evidence is available for most studied factors, and that insufficient analysis methods were used commonly. Therefore, the aim of this study was to add more weight to the existing evidence, about factors that are associated with a more rapid outcome after ACL reconstruction. The second aim was to use multivariate analysis to study the possible factors independently. Methods A cohort study was conducted with a follow-up of six months. Before surgery, patient variables were scored. Surgical variables were scored during arthroscopic ACL reconstructions with a single-bundle technique and hamstring autograft. The Lysholm score and subscales of the Knee Injury Osteoarthritis Outcome Score (KOOS) were assessed six months post surgery. A multiple analysis of variance (ANOVA) model was used to identify prognostic factors for outcome. Results In total, 118 patients were included. Patients, aged ≤30years, with a subjective knee score ≥ six, with normal flexion range of motion (ROM) of the knee, with flexion and extension strength deficit of ≤20%, and those with no previous knee surgery in the same knee at baseline scored significantly higher on outcome after multivariate analysis. No significant effect of surgical factors could be found. Conclusion Younger age, higher subjective knee score, normal knee flexion, normal knee flexion and extension strength, and no previous knee surgery in the patients' history at baseline are associated with a more rapid recovery after ACL reconstruction. Level of evidence Level III, prognostic study.


      PubDate: 2015-08-08T03:31:04Z
       
  • BASK survey of The Knee readership 2015
    • Abstract: Publication date: Available online 4 August 2015
      Source:The Knee
      Author(s): Arash Aframian, David Sands Johnson, Caroline Blanca Hing
      A convenience sample of the attendees of the 2015 annual meeting of the British Association of Knee showed that the majority of the attendees who responded read The Knee, would like a section on surgical tips, more themed supplements and guest editorials. There is still not enough support for purely electronic publication. For those that have submitted papers, the experience with the publication process was positive.


      PubDate: 2015-08-08T03:31:04Z
       
  • The influence of area level social deprivation on preoperative disease
           severity and postoperative outcomes following unicompartmental knee joint
           replacement
    • Abstract: Publication date: Available online 4 August 2015
      Source:The Knee
      Author(s): Damien Bennett, Janet Hill, David Beverland, Frank Kee
      Background This study investigated the effect of socioeconomic deprivation on preoperative disease and outcome following unicompartmental knee replacement (UKR). Methods 307 Oxford UKRs implanted between 2008 and 2013 under the care of one surgeon using the same surgical technique were analysed. Deprivation was quantified using the Northern Ireland Multiple Deprivation Measure. Preoperative disease severity and postoperative outcome were measured using the Oxford Knee Score (OKS). Results There was no difference in preoperative OKS between deprivation groups. Preoperative knee range of motion (ROM) was significantly reduced in more deprived patients with 10° less ROM than least deprived patients. Postoperatively there was no difference in OKS improvement between deprivation groups (p=0.46), with improvements of 19.5 and 21.0 units in the most and least deprived groups respectively. There was no significant association between deprivation and OKS improvement on unadjusted or adjusted analysis. Preoperative OKS, Short Form 12 mental component score and length of stay were significant independent predictors of OKS improvement. A significantly lower proportion of the most deprived group (15%) reported being able to walk an unlimited distance compared to the least deprived group (41%) one year postoperatively. Conclusion More deprived patients can achieve similar improvements in OKS to less deprived patients following UKR. Level of evidence 2b — retrospective cohort study of prognosis.


      PubDate: 2015-08-08T03:31:04Z
       
  • Technique of anatomical single bundle ACL reconstruction with rounded
           rectangle femoral dilator
    • Abstract: Publication date: Available online 7 August 2015
      Source:The Knee
      Author(s): Junsuke Nakase, Tatsuhiro Toratani, Masahiro Kosaka, Yoshinori Ohashi, Hitoaki Numata, Takeshi Oshima, Yasushi Takata, Hiroyuki Tsuchiya
      Background This study aimed to present a new technique for anatomical single bundle anterior cruciate ligament (ACL) reconstruction. We developed an original rounded rectangular dilator set to create rounded rectangular femoral tunnels. This technique can increase the femoral tunnel size without roof impingement, and has the potential to reduce the graft failure rate. We investigated the tunnel position and the incidence of intraoperative complications. Method The presented technique is anatomical single bundle ACL reconstruction using a semitendinosus graft (with or without the gracilis tendon). The tunnel was drilled via an additional medial portal. Rounded rectangular tunnels were created using a special dilator. Tibial tunnels were created using conventional rounded tunnels. Fixation was achieved using a suspensory device on the femoral side and a plate and screw on the tibial side. Patients Fifty patients underwent this surgery, and intraoperative complications were investigated. The femoral tunnel positions were documented postoperatively from computed tomography scans using the quadrant method. The tibial tunnel positions (anterior-to-posterior, medial-to-lateral) were documented using intraoperative X-ray scans. Results Only one patient had a partial posterior tunnel wall blowout. The femoral tunnel length varied between 30 and 40mm (34.9(±SD)3.3mm). All femoral and tibial tunnels were located within the area of the anatomical ACL insertions. Conclusion We did not experience any serious intraoperative complications during anatomical single bundle ACL reconstruction using a rounded rectangle dilator, and the resulting locations of the femoral and tibial tunnels were within the anatomical ACL footprint. Level of evidence Level IV.


      PubDate: 2015-08-08T03:31:04Z
       
  • A new arthroscopic classification of degenerative medial meniscus root
           tear that correlates with meniscus extrusion on magnetic resonance imaging
           
    • Abstract: Publication date: Available online 1 August 2015
      Source:The Knee
      Author(s): Seong-Il Bin, Tae-Wan Jeong, Su-Jin Kim, Dae-Hee Lee
      Background To determine a new classification system for medial meniscus root tears (MMRT) based on arthroscopic findings. Methods 24 knees (55%) belonged to the nondisplaced or overlapped group, and 20 knees (45%) to the widely displaced group. Absolute meniscal extrusion was defined as distance between outer edge of the articular cartilage of tibial plateau and meniscal outer edge. Relative extrusion was defined as extruded meniscus width divided by entire meniscal width, multiplied by 100. The proportion of knees with major (>3mm) extrusion were compared in two groups, as were the severity of chondral wear and osteoarthritic change. Results Absolute (4.6mm vs. 3.7mm, P=0.006) and relative (46% vs. 39%, P=0.042) extrusion of the medial meniscus were greater in widely displaced than in nondisplaced or overlapped group. Medial joint space width was significantly narrower in the widely displaced than in the nondisplaced or overlapped group (3.0mm vs. 4.0mm, P=0.007). The widely displaced group had a 4° greater varus deformity, and higher rates of major extrusion (>3mm), grade III or IV chondral wear in the medial femoral condyle (60% vs. 29%, P=0.039) and medial compartment osteoarthritis (75% vs. 21%, P=0.001) than did the nondisplaced or overlapped group. Conclusions Widely displaced MMRT had greater meniscal extrusion and more severe chondral wear and osteoarthritis than did nondisplaced or overlapped MMRT. In this novel classification system, the stage of MMRT severity was associated with tear site displacement. Level of evidence Case series (level IV).


      PubDate: 2015-08-04T03:20:40Z
       
  • Time-driven activity based costing of total knee replacement surgery at a
           London teaching hospital
    • Abstract: Publication date: Available online 30 July 2015
      Source:The Knee
      Author(s): Alvin Chen, Sanjeeve Sabharwal, Kashif Akhtar, Navnit Makaram, Chinmay M. Gupte
      Introduction The aim of this study was to conduct a time-driven activity based costing (TDABC) analysis of the clinical pathway for total knee replacement (TKR) and to determine where the major cost drivers lay. Methods The in-patient pathway was prospectively mapped utilising a TDABC model, following 20 TKRs. The mean age for these patients was 73.4years. All patients were ASA grade I or II and their mean BMI was 30.4. The 14 varus knees had a mean deformity of 5.32° and the six valgus knee had a mean deformity of 10.83°. Timings were prospectively collected as each patient was followed through the TKR pathway. Results Pre-operative costs including pre-assessment and joint school were £163. Total staff costs for admission and the operating theatre were £658. Consumables cost for the operating theatre were £1862. The average length of stay was 5.25days at a total cost of £910. Trust overheads contributed £1651. The overall institutional cost of a ‘noncomplex’ TKR in patients without substantial medical co-morbidities was estimated to be £5422, representing a profit of £ 1065 based on a best practice tariff of £ 6487. Conclusions The major cost drivers in the TKR pathway were determined to be theatre consumables, corporate overheads, overall ward cost and operating theatre staffing costs. Appropriate discounting of implant costs, reduction in length of stay by adopting an enhanced recovery programme and control of corporate overheads through the use of elective orthopaedic treatment centres are proposed approaches for reducing the overall cost of treatment.


      PubDate: 2015-08-04T03:20:40Z
       
  • Femoral fixation strength following soft-tissue posterolateral corner
           reconstruction using fibular-based technique: Biomechanical analysis of
           four techniques in normal and low-density synthetic bone
    • Abstract: Publication date: Available online 30 July 2015
      Source:The Knee
      Author(s): Robert A. Gallo, Vikram Sathyendra, Neil A. Sharkey, Gregory S. Lewis
      Background Optimal femoral fixation of soft-tissue grafts has been described for anterior cruciate ligament reconstruction. Posterolateral corner reconstruction differs from ACL reconstruction in two ways: (a) soft-tissue fixation into the femur requires two tails and (b) the line of force is different. Our purpose was to determine the optimal femoral fixation of soft-tissue grafts during posterolateral corner reconstructions. We hypothesized that interference screw fixation is the strongest technique in normal-density lateral femoral condyle, whereas, cortically-based fixation techniques are stronger methods in low-density lateral femoral condyle. Methods We evaluated elongation during cyclic loading, yield load, peak load-to-failure, and stiffness of four soft-tissue graft femoral fixation methods during posterolateral corner reconstruction. Our model included bovine flexor tendons and contoured synthetic bones. Grafts were secured to the lateral epicondyle in normal- or low-density bone models using spiked washer, button, interference screw, or button and interference screw. Five specimens for each were tested in each bone density. Analysis of variance using Tukey–Kramer adjustment for multiple hypothesis testing was used. Six cadaver bones whose density was analyzed using computerized tomography scan quantitation were tested using interference screw fixation. Results No method produced significantly stronger yield load or peak load-to-failure in normal-density bone. In low-density bone, cortically-based methods produced significantly higher yield load or peak load-to-failure. Yield load or peak load-to-failure was significantly higher in normal-density bone when using spiked washer or interference screw fixation. Conclusion No femoral fixation method tested produced superior yield load or peak load-to-failure. Spiked washer and interference screw fixation are inferior fixation methods in low-density bone. Clinical relevance For fibular-based posterolateral corner reconstructions, all fixation methods tested are acceptable in high-density bone, while cortical fixation methods should be considered in low-density bone.


      PubDate: 2015-07-30T21:17:35Z
       
  • Treatment of infected nonunion total knee arthroplasty periprosthetic
           fracture using a stemmed articulating spacer
    • Abstract: Publication date: Available online 26 July 2015
      Source:The Knee
      Author(s): Hee-Nee Pang, Renyi Benjamin Seah, Steven J. MacDonald
      Background We present a case of multifocal infection involving the left total hip replacement and the right total knee replacement of a patient, further complicated by an infected non-union of a periprosthetic fracture of the right knee. This required the unique simultaneous management of both infection eradication and fracture stabilization in the knee. Methods Both sites were treated with a two-stages procedure, including the novel use of a stemmed articulating spacer for the right knee. This spacer was made combining a retrograde humeral nail, coated with antibiotic-impregnated cement, and a pre-formed articulating cement spacer. The patient was able to weight-bear on this spacer. Results The fracture went on to unite, and a second stage was performed with the use of stemmed prosthesis and augments. She remains infection free two years after the second stage operation. Conclusions The use of a stemmed articulating knee spacer can facilitate infection eradication and fracture stabilization while preserving some motion and weight-bearing ability in the two-stages management of an infected periprosthetic fracture of the knee. Level of evidence Level V (Case report).


      PubDate: 2015-07-27T04:42:27Z
       
  • Assessment of the injection behavior of commercially available bone BSMs
           for Subchondroplasty® procedures
    • Abstract: Publication date: Available online 23 July 2015
      Source:The Knee
      Author(s): Dinely A. Colon, Byung Jo Victor Yoon, Thomas Anthony Russell, Frank P. Cammisa, Celeste Abjornson
      Background Bone substitute materials (BSMs) have been commercially available for over 30years and have been used extensively in orthopedic procedures. Some BSMs are described as “injectable.” With rising focus on minimally invasive surgical procedures, the range of applications in which these materials are injectable is of clinical interest. Specifically, their performance in closed, pressurized environments in the trabecular bone with microdamage or abnormal bone remodeling have not been well characterized. This issue arises often in the presence of bone marrow lesions of the subchondral bone in early onset osteoarthritis. The objective was to evaluate the in vitro injectability of several common commercially available BSMs. It was hypothesized that some materials self-described as “injectable” would fail to function in a small microarchitecture in comparison to the large void areas. Methods Mechanical testing was performed and force data was collected. Each sample was additionally radiographed and then imaged under micro-computed tomography (CT). Results Most of the BSM materials failed to be successfully injected into a simulated trabecular model. Simplex™, AccuFill® and StrucSure™ materials were the only ones that were injected successfully. Many of the materials underwent phase separation at higher pressures and were not able to be deployed from the injection syringe. In addition, a clinically relevant difference was seen between the manners in which the materials interdigitated into the existing structure. Conclusion The AccuFill® was the only material able to inject in a closed model and demonstrate adequate implantation of BSM into the simulated trabecular bone. Clinical Relevance Injectability of BSMs is clinically relevant as the interest in minimally invasive surgical procedures is rising rapidly.


      PubDate: 2015-07-27T04:42:27Z
       
  • MRI-based analysis of patellofemoral cartilage contact, thickness, and
           alignment in extension, and during moderate and deep flexion
    • Abstract: Publication date: Available online 23 July 2015
      Source:The Knee
      Author(s): Benjamin R. Freedman, Frances T. Sheehan, Amy L. Lerner
      Background Several factors are believed to contribute to patellofemoral joint function throughout knee flexion including patellofemoral (PF) kinematics, contact, and bone morphology. However, data evaluating the PF joint in this highly flexed state have been limited. Therefore, the purpose of this study was to evaluate patellofemoral contact and alignment in low (0°), moderate (60°), and deep (140°) knee flexion, and then correlate these parameters to each other, as well as to femoral morphology. Methods Sagittal magnetic resonance images were acquired on 14 healthy female adult knees (RSRB approved) using a 1.5T scanner with the knee in full extension, mid-flexion, and deep flexion. The patellofemoral cartilage contact area, lateral contact displacement (LCD), cartilage thickness, and lateral patellar displacement (LPD) throughout flexion were defined. Intra- and inter-rater repeatability measures were determined. Correlations between patellofemoral contact parameters, alignment, and sulcus morphology were calculated. Results Measurement repeatability ICCs ranged from 0.94 to 0.99. Patellofemoral cartilage contact area and thickness, LCD, and LPD were statistically different throughout all levels of flexion (p<0.001). The cartilage contact area was correlated to LPD, cartilage thickness, sulcus angle, and epicondylar width (r=0.47–0.72, p<0.05). Discussion This study provides a comprehensive analysis of the patellofemoral joint throughout its range of motion. Conclusions This study agrees with past studies that investigated patellofemoral measures at a single flexion angle, and provides new insights into the relationship between patellofemoral contact and alignment at multiple flexion angles. Clinical Relevance The study provides a detailed analysis of the patellofemoral joint in vivo, and demonstrates the feasibility of using standard clinical magnetic resonance imaging scanners to image the knee joint in deep flexion.


      PubDate: 2015-07-27T04:42:27Z
       
  • Joint contact forces when minimizing the external knee adduction moment by
           gait modification: A computer simulation study
    • Abstract: Publication date: Available online 26 July 2015
      Source:The Knee
      Author(s): Ross H. Miller, Aryeh Y. Esterson, Jae Kun Shim
      Background and purpose Gait modification is often used to reduce the external knee adduction moment (KAM) in human walking, but the relationship between KAM reduction and changes in medial knee joint contact force (JCF) is not well established. Our purpose was to examine the limiting case of KAM-based gait modification: reducing the KAM as much as possible, and the resulting effects on JCF. Methods We used musculoskeletal modeling to perform three optimal control simulations: normal walking, a modified gait that reduced the KAM as much as theoretically possible (Min(KAM) simulation), and a second modified gait that minimized the KAM plus the metabolic cost of transport (Min(KAM+CoT) simulation). Results The two modified gaits both reduced the peak KAM from normal walking (−82% for Min(KAM) simulation, −74% for Min(KAM+CoT) simulation) by increasing trunk lean, toe-out, and step width, and reducing knee flexion. Even though the Min(KAM+CoT) simulation had the larger KAM, it had a greater reduction in peak medial JCF (−27%) than the Min(KAM) simulation (−15%) because it reduced the KAM using less knee muscle activity. These results were qualitatively robust to a sensitivity analysis of the knee joint model, but the magnitude of changes varied by an order of magnitude. Conclusions The results suggest that (i) gait modification can benefit from considering whole-body motion rather than single adjustments, (ii) accurate interpretation of KAM effects on medial JCF requires consideration of muscle forces, and (iii) subject-specific knee models are needed to accurately determine the magnitude of KAM reduction effects on JCF.


      PubDate: 2015-07-27T04:42:27Z
       
  • Multi-joint postural behavior in patients with knee osteoarthritis
    • Abstract: Publication date: Available online 15 July 2015
      Source:The Knee
      Author(s): Katia Turcot, Yoshimasa Sagawa, Pierre Hoffmeyer, Domizio Suvà, Stéphane Armand
      Background Previous studies have demonstrated balance impairment in patients with knee osteoarthritis (OA). Although it is currently accepted that postural control depends on multi-joint coordination, no study has previously considered this postural strategy in patients suffering from knee OA. The objectives of this study were to investigate the multi-joint postural behavior in patients with knee OA and to evaluate the association with clinical outcomes. Methods Eighty-seven patients with knee OA and twenty-five healthy elderly were recruited to the study. A motion analysis system and two force plates were used to investigate the joint kinematics (trunk and lower body segments), the lower body joint moments, the vertical ground reaction force ratio and the center of pressure (COP) during a quiet standing task. Pain, functional capacity and quality of life status were also recorded. Results Patients with symptomatic and severe knee OA adopt a more flexed posture at all joint levels in comparison with the control group. A significant difference in the mean ratio was found between groups, showing an asymmetric weight distribution in patients with knee OA. A significant decrease in the COP range in the anterior–posterior direction was also observed in the group of patients. Only small associations were observed between postural impairments and clinical outcomes. Conclusion This study brings new insights regarding the postural behavior of patients with severe knee OA during a quiet standing task. The results confirm the multi-joint asymmetric posture adopted by this population.


      PubDate: 2015-07-18T21:45:21Z
       
  • Nanofractured autologous matrixinduced chondrogenesis (NAMIC©)
           — Further development of collagen membrane aided chondrogenesis
           combined with subchondral needling
    • Abstract: Publication date: Available online 16 July 2015
      Source:The Knee
      Author(s): Jan P. Benthien, Peter Behrens
      Purpose This technical note introduces a further development of the autologous matrix induced chondrogenesis (AMIC©) technology for regenerative surgery of cartilage defects considering latest data in the literature. The potential of subchondral mesenchymal stem cell stimulation for cartilage repair is combined with a membrane technique to enhance efficiency of cartilage regeneration. The nanofractured autologous matrixinduced chondrogenesis (NAMIC©) procedure is suitable for the knee, hip, ankle, shoulder and elbow joints. Methods A standardized subchondral needling procedure (nanofracturing) is combined with fixation of a collagen I/III membrane to regenerate cartilage defects. Its advantages over microfracturing are smaller holes, deeper perforation into the subchondral space, a standardized procedure and earlier rehabilitation of the patient. The collagen membrane protects the blood clot forming after nanofracturing. The NAMIC© procedure may be performed arthroscopically alone, or in a combined arthroscopic setting with a mini-arthrotomy. Results This is a further development of the AMIC© technology which allows earlier rehabilitation of the patient. The procedure is standardized. Early clinical results are encouraging. Nevertheless, caution is advised in the evaluation of this method as in that of any cartilage regenerating method. Conclusion The development of standardized subchondral regenerative procedures is important as only reliable clinical studies will give non-biased results. The NAMIC© procedure and the nanofracturing associated with it could be a promising step. As the rehabilitation period may be significantly shortened there is an earlier re-integration of the patient into the working life as compared to the AMIC© procedure. Level of Evidence 4.


      PubDate: 2015-07-18T21:45:21Z
       
  • Modelling knee flexion effects on joint power absorption and adduction
           moment
    • Abstract: Publication date: Available online 18 July 2015
      Source:The Knee
      Author(s): Hanatsu Nagano, Ichiroh Tatsumi, Eri Sarashina, W.A. Sparrow, Rezaul K. Begg
      Background Knee osteoarthritis is commonly associated with ageing and long-term walking. In this study the effects of flexing motions on knee kinetics during stance were simulated. Extended knees do not facilitate efficient loading. It was therefore, hypothesised that knee flexion would promote power absorption and negative work, while possibly reducing knee adduction moment. Methods Three-dimensional (3D) position and ground reaction forces were collected from the right lower limb stance phase of one healthy young male subject. 3D position was sampled at 100Hz using three Optotrak Certus (Northern Digital Inc.) motion analysis camera units, set up around an eight metre walkway. Force plates (AMTI) recorded ground reaction forces for inverse dynamics calculations. The Visual 3D (C-motion) ‘Landmark’ function was used to change knee joint positions to simulate three knee flexion angles during static standing. Effects of the flexion angles on joint kinetics during the stance phase were then modelled. Results The static modelling showed that each 2.7° increment in knee flexion angle produced 2.74°–2.76° increments in knee flexion during stance. Increased peak extension moment was 6.61Nm per 2.7° of increased knee flexion. Knee flexion enhanced peak power absorption and negative work, while decreasing adduction moment. Conclusions Excessive knee extension impairs quadriceps' power absorption and reduces eccentric muscle activity, potentially leading to knee osteoarthritis. A more flexed knee is accompanied by reduced adduction moment. Research is required to determine the optimum knee flexion to prevent further damage to knee-joint structures affected by osteoarthritis.


      PubDate: 2015-07-18T21:45:21Z
       
  • Custom-made lateral femoral hemiarthroplasty for traumatic bone loss: A
           case report
    • Abstract: Publication date: Available online 14 July 2015
      Source:The Knee
      Author(s): Bart Stuyts , Geert Peersman , Emmanuel Thienpont , Elke Van den Eeden , Hans Van der Bracht
      We report the case of a 32-year-old male patient involved in a road traffic accident in which he sustained a grade II open supra- and intercondylar fracture of the left distal femur with substantial bone loss of the lateral femoral condyle and trochlea (AO classification type 33 C3). Normal knee function was no longer possible, as the patella was trapped within the bony defect. Existing reconstructive options such as unicondylar osteoarticular allograft, arthrodesis, and arthroplasty were considered. However, as all these techniques present significant disadvantages, particularly in young and active patients, a custom-made lateral hemiarthroplasty was designed and implanted as an alternative treatment. Follow-up at 24months revealed an excellent, pain-free level of function and radiographs showed no signs of implant loosening or migration. This technique offers the most anatomical means of reconstruction with maximal preservation of the bone stock, thereby better facilitating any revisions that may be necessary in the future. This is an experimental technique reserved for rare indications, and currently has no long-term follow-up results associated with its use. Additional research is therefore needed before widespread adoption of this technique can take place.


      PubDate: 2015-07-14T14:15:05Z
       
  • Measurements of tunnel placements after anterior cruciate ligament
           reconstruction — A comparison between CT, radiographs and MRI
    • Abstract: Publication date: Available online 10 July 2015
      Source:The Knee
      Author(s): Anagha P. Parkar , Miraude E.A.P.M. Adriaensen , Cornelia Fischer-Bredenbeck , Eivind Inderhaug , Torbjørn Strand , Jörg Assmus , Eirik Solheim
      Background A non-anatomic placement of the femoral and tibial tunnels may affect outcome in anterior cruciate ligament (ACL) reconstructions. Tunnel placements are validated with varying imaging modalities. We compared measurements of tunnel placements between radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) in a clinical setting, assessed the reliability and aimed to decide on a possible “gold standard”. Methods All patients who had undergone at least two of three modalities, radiographs, MRI and CT, after ACL reconstruction between January 2011 and June 2013 were included. Two radiologists measured tunnel placements according to a standardized protocol. Interobserver agreement was assessed with intraclass correlation coefficients (ICC), the intermodality differences with Bland–Atman plots. Radiation data for CT studies were collected. Results Forty-six CTs, 45 radiographs and 30 MRIs were reviewed. Femoral inter-observer agreement for radiographs was ICC=0.64, for CT ICC=0.86 and for MRI ICC=0.75. Tibial inter-observer agreement for radiographs was ICC=0.92, for CT-mip ICC=0.91, for CT and MRI ICC=0.87. No intermodality differences between the femoral measurements were observed. In the tibia, there were differences between radiographs and CT (−3.9%), radiographs-MRI (−3.6%), CT–CTmip (3.2%) and CTmip–MRI (−3.1%). The effective radiation doses varied between 0.025 and 0.045mSv, mean and median was 0.033mSv. Conclusion There were differences in the tibial measurements between summation and single slice images. Only 3D–CT depicted the femoral tunnel in both directions. CT was consistently reliable in both femoral and tibial measurements. Effective radiation dose from CT was lower than previously reported. CT can safely be used in routine clinical practice to evaluate tunnel placements after ACL reconstruction. Level of evidence Level III — study of diagnostic test without a universally applied “gold standard”.


      PubDate: 2015-07-14T14:15:05Z
       
  • The effect of femoral tunnel widening on one-year clinical outcome after
           anterior cruciate ligament reconstruction using Ziploop® technology
           for fixation in the cortical bone of the femur
    • Abstract: Publication date: Available online 3 July 2015
      Source:The Knee
      Author(s): Benjamin Basson , Rémi Philippot , Thomas Neri , Jean François Meucci , Bertrand Boyer , Frédéric Farizon
      Background The effect of femoral tunnel widening on clinical results after anterior cruciate ligament (ACL) reconstruction has rarely been investigated. In our study, ACL reconstructions were performed using semitendinosus and gracilis (STG) tendon grafts and single cortical fixation on the femoral side. The aim was to analyse femoral tunnel widening at one year and evaluate the effect of femoral tunnel widening on clinical and laximetric outcome. Methods Forty-six patients were enrolled in this prospective continuous single operator monocenter study. Clinical protocol included preoperative and one-year evaluation with subjective and objective clinical scores of the International Knee Documentation Committee (IKDC). Computerized tomography (CT) scan was used for radiographic examination at one-year follow-up. The amount of femoral tunnel widening was measured by means of the 3D image processing OsiriX software. The cross-sectional area of each tunnel was measured at four different locations. Results The subjective IKDC score improved from a preoperative score of 50 to a one-year postoperative score of 81.8. The side-to-side difference in knee laxity evolved from 2.94mm to 0.74mm. The objective IKDC score at last follow-up was rated A in 27 patients and B in 17. CT scan data revealed a mean cone shape widening of the femoral tunnel of 49.32%. Femoral tunnel widening at the level of the joint (F4) was negatively correlated with the IKDC subjective score at one year. Conclusion This study revealed a significant widening of the femoral tunnel by demonstrating its conical shape at one postoperative year. A significant correlation could be established between femoral tunnel widening close to the joint and IKDC scores.


      PubDate: 2015-07-05T13:37:45Z
       
  • A suspected genetic form of bilateral osteochondritis dissecans of the
           knee in a Dutch family
    • Abstract: Publication date: Available online 27 June 2015
      Source:The Knee
      Author(s): J. Gorter , J.J.A.M. van Raay
      Osteochondritis dissecans (OCD) mostly has an idiopathic origin, but syndromic and familial forms have been reported. Mutations of the aggrecan (ACAN) and COL9A2 genes are associated with familial OCD, but these patients present with syndromic features. This article describes a mother and a daughter who both have bilateral OCD of the medial femoral condyles, and the monozygotic twin sister of the mother who has confirmed unilateral OCD (and possible bilateral OCD) of the medial femoral condyle. No short stature or any other syndromic features were present. None of the syndromic features associated with ACAN or COL9A2 mutations or any other known syndromes were present in this case. This case suggests a possible unknown genetic anomaly. Level of evidence: IV case report.


      PubDate: 2015-07-01T12:57:34Z
       
  • Hip abductor strength in people with knee osteoarthritis: A
           cross-sectional study of reliability and association with function
    • Abstract: Publication date: Available online 30 June 2015
      Source:The Knee
      Author(s): Michael A. Tevald , Amanda Murray , Brittney A. Luc , Kafai Lai , David Sohn , Brian Pietrosimone
      Background To investigate the clinical importance of hip abductor (HA) strength in people with knee osteoarthritis (OA), the purposes of this study were to 1) compare the association of HA strength and physical function to that of knee extensor (KE) strength and physical function, and 2) determine the reliability of the assessment of HA strength using a hand-held dynamometer. Methods Thirty-five individuals [58 years standard deviation 10 years old] with knee osteoarthritis participated. Physical function was assessed with performance-based [Get-Up and Go (GUG), stair climb and descent (SC), and five times chair rise (CR)] and self-reported (WOMAC function) measures. The relationship between strength and function was assessed using bivariate correlation and hierarchical multiple regression models. Reliability across sessions was assessed in 25 subjects. Results In the bivariate models, both KE and HA strength were both significantly associated with performance-based measures of function, but not WOMAC function. After controlling for anthropometric factors and KE strength in the hierarchical models, HA made significant independent contributions to the prediction of GUG and SC, but not CR or WOMAC function. The reliability of HA strength was excellent (ICC2, 3 =0.94; 95% CI=0.86–0.97), while the minimum detectable change (MDC95) was 0.29Nm/kg (95% CI=0.23–0.41). Conclusion HA strength can be reliably measured and is closely associated with functional performance in people with knee OA. Clinical Relevance These results provide preliminary evidence suggesting that HA strength may be an important rehabilitation target for the conservative management of knee OA.


      PubDate: 2015-07-01T12:57:34Z
       
  • Clinical and functional outcome after anterior cruciate ligament
           reconstruction using the LARS™ system at a minimum follow-up of
           10years
    • Abstract: Publication date: Available online 27 June 2015
      Source:The Knee
      Author(s): Thomas M. Tiefenboeck , Elisabeth Thurmaier , Michael M. Tiefenboeck , Roman C. Ostermann , Julian Joestl , Markus Winnisch , Mark Schurz , Stefan Hajdu , Marcus Hofbauer
      Background Since the 1980's several artificial ligaments were used for reconstruction of the anterior cruciate ligament (ACL) serving different complications. The aim of this study was to assess the clinical and functional outcomes of primary ACL reconstruction using the Ligament Augmentation Reconstruction System (LARS™) with a minimum follow-up of 10-years. The LARS™ presents a synthetic material consisting of non-absorbing polyethylene terephthalate fibres used for ligament reconstruction. Methods Outcomes of 18 patients who underwent arthroscopic ACL reconstruction using the LARS™ system between 2000 and 2004 with a minimum follow-up of 10years were observed. The International Knee Documentation Committee score (IKDC), Visual Analog Scale (VAS), Lysholm score, and Tegner Activity Scale were assessed. Clinical assessment was performed by Lachman testing, assessment of side-to-side difference on KT-2000 testing and plain radiography evaluation of osteoarthritis. Results There were seven males and 11 females, mean age 29years (range, 18 to 44years) and a mean follow-up of 151.5 months. Five patients (27.8%) sustained a re-rupture of the LARS™ system and underwent revision surgery after a mean time of 23months and four patients (22.2%) presented with a re-rupture. The average IKDC score was 76.60±18.18, the average Lysholm score was 88.00±10.07 and the average Tegner activity score was five at final follow-up. Conclusion Our results indicate that the LARS™ system should currently not be suggested as a potential graft for primary reconstruction of the ACL. In special cases, however, the LARS™ system can serve as an alternative graft. Level of evidence: Level IV, retrospective study.


      PubDate: 2015-07-01T12:57:34Z
       
  • Case series: Revision anterior cruciate ligament reconstructions using
           patellar tendon autografts
    • Abstract: Publication date: Available online 27 June 2015
      Source:The Knee
      Author(s): Yuji Takazawa , Hiroshi Ikeda , Yoshitomo Saita , Muneaki Ishijima , Masataka Nagayama , Haruka Kaneko , Yohei Kobayashi , Shinnosuke Hada , Ryo Sadatsuki , Kazuo Kaneko
      Background Using intra-operative findings and clinical results, including return to play (RTP) at the pre-injury level, this study investigated the causes of primary graft failure after revision anterior cruciate ligament (ACL) reconstruction with bone–patellar-tendon–bone (BPTB) autografts. Methods A total of 54 patients were followed for a mean of 38.2±10.2months post-surgery. Subjective and objective results were evaluated using single assessment numeric evaluation (SANE) scores, Lachman tests, KT-2000 arthrometer results, and pivot-shift tests. The change in each patient's Tegner activity scale and RTP at the pre-injury level were also evaluated. Results Inappropriate positioning of the tunnels was the most important reason (54%) for primary graft failure. After revision surgery, anterior knee stability was significantly improved (1.2 (mean)±1.2 (SD)mm vs 4.5(mean) ±1.9 (SD)mm; P<0.01). Two (4%) patients sustained revision graft ruptures while two (4%) sustained contralateral knee ACL tears. The rate of RTP at the pre-injury level was 67% (36 patients), and mean SANE scores at the time of RTP were higher than before surgery (74.8±13.8 points vs 24.1±16.4; P<0.001). The average time from primary graft failure to revision surgery was shorter (12.2 (mean)±4.0 (SD) vs 37.6 (mean)±8.8 (SD)months; P<0.01) and the ratio of major cartilage injury was lower (39% vs 83%; P<0.05) in the RTP group than that in the non-RTP group. Conclusions The time from primary graft failure to revision surgery and the extent of the cartilage injury are major factors in RTP after revision ACL reconstructions.


      PubDate: 2015-07-01T12:57:34Z
       
  • Effects of an unloader knee brace on knee-related symptoms and function in
           people with post-traumatic knee osteoarthritis after anterior cruciate
           ligament reconstruction
    • Abstract: Publication date: Available online 25 June 2015
      Source:The Knee
      Author(s): Harvi F. Hart , Kay M. Crossley , David C. Ackland , Sallie M. Cowan , Natalie J. Collins
      Background and purpose This pilot study evaluated the immediate and four-week effects of an unloader knee brace on knee-related symptoms and performance-based function in people with knee osteoarthritis (OA) after anterior cruciate ligament reconstruction (ACLR). Methods Individuals with knee OA, five to 20years post-ACLR, were recruited for two within-subject randomized studies: immediate effects (n=18) and four-week effects (n=11). Patient-reported knee-related symptoms (knee pain, perceived task difficulty, confidence, stability) were assessed during hop for distance and step-down tests, while performance-based function was assessed with hopping distance under three conditions: i) no brace; ii) unadjusted brace (sagittal plane support); and iii) adjusted brace (sagittal plane support with varus/valgus readjustment). Participants in the four-week brace effect study were randomized to wear the unadjusted or adjusted brace for four weeks after baseline (no brace) testing, and repeated tests in their allocated brace at four-week follow-up. Friedman tests evaluated differences between the three brace conditions for each variable for the immediate brace effect study (p<0.05), and Wilcoxon signed-rank tests evaluated differences between no brace and allocated brace for the four-week study (p<0.05). Results The adjusted and unadjusted unloader braces produced immediate improvements in knee confidence during hop for distance, and knee pain during step-down. Following the four-week brace intervention, the allocated brace improved knee confidence, perceived task difficulty and stability during hop for distance; and knee pain, perceived task difficulty, confidence, and stability during step-down. Conclusions The unloader knee brace, adjusted or unadjusted, has the potential to improve knee-related symptoms associated with knee OA after ACLR.


      PubDate: 2015-06-26T12:42:54Z
       
  • Total knee arthroplasty using patient-specific guides: Is there a learning
           curve?
    • Abstract: Publication date: Available online 26 June 2015
      Source:The Knee
      Author(s): Jason Chinnappa , Darren B. Chen , Ian A. Harris , Samuel J. MacDessi
      Background Patient specific guides (PSG) have been reported to improve overall component alignment in total knee arthroplasty (TKA). With more surgeons likely to consider this method of TKA in the future, this study was performed to establish whether there is a learning curve with use of PSG in TKA. Methods Eighty-six consecutive PSG TKAs performed by one surgeon were retrospectively analyzed in two groups. The first 30 patients were compared to the second 56 patients with regards to their operative times and post-operative multi-planar alignments on computed tomography (CT) scan. Results Mean operative time was higher in the initial 30 cases compared to the second 56 cases (85min vs. 78min; p=0.001). No statistically significant differences were found in post-operative TKA alignment between the two groups. Conclusions This study suggests that there is a minimal learning curve with operative time associated with use of PSG in TKA. This study was unable to detect a significant learning curve with regards to restoration of mechanical knee alignment with the use of PSG in TKA. Level of Evidence: Level III, retrospective comparative study.


      PubDate: 2015-06-26T12:42:54Z
       
  • The UK National Ligament Registry Report 2015
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Ayman Gabr , Sean O'Leary , Tim Spalding , Steven Bollen , Fares Haddad



      PubDate: 2015-06-26T12:42:54Z
       
  • The Stiff Knee
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Hermann O. Mayr , Alfred Hochrein



      PubDate: 2015-06-26T12:42:54Z
       
  • Peri-operative practice in knee arthroscopy: A web-based survey of British
           Association for Surgery of the Knee (BASK) members
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Sujay Dheerendra , Ravi Pydisetty



      PubDate: 2015-06-26T12:42:54Z
       
  • British Association for Surgery of the Knee
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4




      PubDate: 2015-06-26T12:42:54Z
       
  • Instructions for Authors
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4




      PubDate: 2015-06-26T12:42:54Z
       
  • Lower limb alignment control: Is it more challenging in lateral compared
           to medial unicondylar knee arthroplasty?
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Saker Khamaisy , Brian P. Gladnick , Denis Nam , Keith R. Reinhardt , Thomas J. Heyse , Andrew D. Pearle
      Introduction Limb alignment after unicondylar knee arthroplasty (UKA) has a significant impact on outcomes. The literature lacks lateral UKA alignment studies, making our understanding of this issue based on medial UKA. Methods We evaluated limb alignment in 241 patients who underwent medial (229 knees) or lateral (37 knees) UKA. Alignment was measured pre and postoperatively in radiographs and intra-operatively using a navigation system. We compared the percentage of over-correction and the difference between post-operative alignment and navigation measurement. Results Percentage of overcorrection was significantly higher in the lateral UKAs (11%) compared to the medial UKAs (4%). In medial UKAs, the mean difference between the intraoperative alignment and the post-operative was 1.33°. This was significantly lower than the mean 1.86° difference in the lateral UKAs. Conclusions Our data demonstrated an increased risk of “overcorrection,” and greater difficulty in predicting postoperative alignment using computer navigation, when performing lateral UKAs compared to medial UKAs.


      PubDate: 2015-06-26T12:42:54Z
       
  • Role of magnetic resonance imaging in the diagnosis of the painful
           unicompartmental knee arthroplasty
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Caroline N. Park , Hendrik A. Zuiderbaan , Anthony Chang , Saker Khamaisy , Andrew D. Pearle , Anil S. Ranawat
      Background Unicompartmental knee arthroplasty (UKA) is a well established method for the treatment of single compartment arthritis; however, a subset of patients still present with continued pain after their procedure in the setting of a normal radiographic examination. This study investigates the effectiveness of magnetic resonance imaging (MRI) in guiding the diagnosis of the painful unicompartmental knee arthroplasty. Methods An IRB-approved retrospective review identified 300 consecutive UKAs performed over a three years period with 28 cases of symptomatic UKA (nine percent) with normal radiographic images. Results MRI examination was instrumental in finding a diagnosis that went undetected on radiographs. Based on MRI findings, 10 (36%) patients underwent surgery whilst 18 (64%) were treated conservatively. Conclusion This study supports the use of MRI as a valuable imaging modality for managing symptomatic unicompartmental knee arthroplasty. Level of evidence Case series


      PubDate: 2015-06-26T12:42:54Z
       
  • Modes of failure and revision of failed lateral unicompartmental knee
           arthroplasties
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Mustafa Citak , Michael B. Cross , Thorsten Gehrke , Kathrin Dersch , Daniel Kendoff
      Background Even with the resurgence of interest in unicompartmental knee arthroplasty (UKA) in recent years, lateral UKA is still performed 10 times less frequently than medial UKA. Hence, because of the infrequency of this procedure, a paucity of outcome studies exist on lateral unicompartmental knee arthroplasty. This retrospective study was performed to analyze the main causes of failure, as well as the time to failure following lateral UKA. Methods A total of 16 consecutive failed lateral UKAs were revised at our institution and were retrospectively reviewed. Causes of failure and time to failure were analyzed based on the medical records and radiographs at the time of revision. Results The mean time from index arthroplasty to revision surgery was 9.4years. In three cases, lateral UKA was converted to primary TKA and in the remaining thirteen cases, revision knee joint systems were used. Seven out of the 16 patients (43.8%) were revised within five years after the index surgery. Overall, the most common reason for failure was progression of arthritis of the medial and/or patellofemoral compartments (56.3%) followed by aseptic loosening (18.8%). Conclusions In conclusion, similar to published reports on medial UKA, the main reason for early and late failure after lateral UKA was progression of arthritis in other compartments. Level of evidence IV


      PubDate: 2015-06-26T12:42:54Z
       
  • The cemented twin-peg Oxford partial knee replacement survivorship: A
           cohort study
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Stephen H. White , Sharon Roberts , Jan Herman Kuiper
      Background A new twin-peg version of the Oxford knee was introduced in 2003. However, until now there has been no information about its survivorship. The aim of this study was to determine the survivorship, and the patients' perception of outcome over time. Methods A cohort of all patients treated from 2003 until 2009 using the twin-peg Oxford partial knee was contacted. The main indication for treatment was anteromedial osteoarthritis (AMOA). The Oxford Knee Score (OKS), American Knee Society Functional (AKS-F) score and satisfaction rate were obtained, and the time-to-failure was used to perform a survival analysis. Results There were 249 patients treated, with 288 medial cemented implants. Of these, 248 patients with 287 implants could be contacted and implant survival or failure was verified. Their mean age was 67years (range: 34–94). The mean follow-up time was 5.1years (maximum: 9.2). The nine years cumulative implant survival rate for all cases using revision for any reason to define failure was 98% (95% CI, 84 to 100). There were no cases of femoral loosening. The mean OKS was 22 pre-operatively, 41 at two years, and 41 at final review, at which point 96% of patients were very or fairly pleased with the result. Conclusion The survivorship of the twin-peg knee was better than that of the single peg knee at our centre, and appeared no worse than the results of the single peg knee at the originating centre. It can offer secure femoral fixation, sustained clinical benefit and patient satisfaction. Level of evidence Level IV case-series.


      PubDate: 2015-06-26T12:42:54Z
       
  • Factors influencing the outcome of deep infection following total knee
           arthroplasty
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Naoki Nakano , Tomoyuki Matsumoto , Kazunari Ishida , Nobuhiro Tsumura , Hirotsugu Muratsu , Takafumi Hiranaka , Ryosuke Kuroda , Masahiro Kurosaka
      Background Whereas clinical studies have revealed a number of important risk factors for postoperative infection following total knee arthroplasty (TKA), it is unclear which factor influences clinical results. A multicenter study was therefore performed by reviewing 51 patients with deep infection after TKA and seeking for the factors related to clinical outcomes. Methods Fifty-one deep infections after TKA were treated from 2000 to 2011 at the multicenter including a university or three arthroplasty centers. Among them, two clinical outcome measures including retention of prosthesis at initial treatment and functional prosthetic knee were assessed for several factors such as age, sex, primary diagnosis, onset time after primary TKA, type of hospital where the primary TKA was performed and the organism's resistance to methicillin using the logistic regression analysis model. Results Among the factors, type of hospital where the primary TKA was performed and onset time after primary TKA had higher multivariable-adjusted odds ratios (ORs) for retention of primary prosthesis (ORs 35.21 and 11.69, respectively.). The cases which primary surgery were performed in arthroplasty centers had higher multivariable-adjusted ORs for functional prosthetic knee (OR 4.9). Thirty-one infection cases with non-methicillin-resistant organisms were all able to keep functional prosthetic knee after the operation, whereas 13 out of 20 infection cases with methicillin-resistant organisms lost their knee function after the operation. Conclusions Onset time after primary TKA, type of hospital where the primary surgery was performed and the organism's resistance to methicillin are important factors influencing the clinical outcomes after infected TKA. Level of Evidence Level 3. Retrospective comparative study.


      PubDate: 2015-06-26T12:42:54Z
       
  • Prospective randomised trial comparing unlinked, modular bicompartmental
           knee arthroplasty and total knee arthroplasty: A five years follow-up
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Nicholas Eng Meng Yeo , Jerry Yongqiang Chen , Andy Yew , Shi-Lu Chia , Ngai Nung Lo , Seng Jin Yeo
      Background A significant proportion of patients with knee osteoarthritis have articular degeneration that is limited to the medial and patellofemoral compartments. The objective of this study was to compare clinical outcomes of unlinked bicompartmental knee arthroplasty (BCA) and total knee arthroplasty (TKA) at 5years in this subset of patients. Methods 48 patients were randomised into two groups: unlinked, modular bicompartmental arthroplasty and total knee arthroplasty. Data on demographics and clinical outcomes were collected (Bartlett Knee Score, Oxford Knee Score, Knee Society Score). Data on intra-operative blood loss in both groups were also recorded. Results Out of the 48 patients, 26 underwent BCA and 22 had TKA. Both groups shared similar demographic profiles. At five years post surgery, there was significant improvement across all functional scores in both groups. However, there was no significant difference in outcome scores in the BCA group compared to the TKA group. The drop in serum haemoglobin levels postoperatively was 1.55 and 2.30g/dl for the BCA and TKA groups respectively (p<.001). The total amount of blood loss was 397 and 647ml respectively (p=.001). Conclusions Unlinked, modular BCA results in similar clinical and functional scores as TKA for medial and patellofemoral arthritis in the mid-term. Intra-operative blood loss was significantly lower in the BCA group compared to the TKA group. BCA is a viable option for a select group of young and active patients with the advantage of reduced intra-operative blood loss and equivalent functional outcomes as TKA.


      PubDate: 2015-06-26T12:42:54Z
       
  • Rehabilitation following first-time patellar dislocation: A randomised
           controlled trial of purported vastus medialis obliquus muscle versus
           general quadriceps strengthening exercises
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): T.O. Smith , R. Chester , J. Cross , N. Hunt , A. Clark , S.T. Donell
      Background We aimed to define whether distal vastus medialis (VM) muscle strengthening improves functional outcomes compared to general quadriceps muscle strengthening following first-time patellar dislocation (FTPD). Methods Fifty patients post-FTPD were randomised to either a general quadriceps exercise or rehabilitation programme (n=25) or a specific-VM exercise and rehabilitation regime (n=25). The primary outcome was the Lysholm knee score, and secondary outcomes included the Tegner Level of Activity score, the Norwich Patellar Instability (NPI) score, and isometric knee extension strength at various knee flexion ranges of motion. Outcomes were assessed at baseline, six weeks, six months and 12months. Results There were statistically significant differences in functional outcome and activity levels with the Lysholm knee score and Tegner Level of Activity score at 12months in the general quadriceps exercise group compared to the VM group (p=0.05; 95% confidence interval (CI): −14.0 to 0.0/p=0.04; 95% CI: −3.0 to 0.0). This did not reach a clinically important difference. There was no statistically significant difference between the groups for the NPI score and isometric strength at any follow-up interval. The trial experienced substantial participant attrition (52% at 12months). Conclusions Whilst there was a statistical difference in the Lysholm knee score and Tegner Level of Activity score between general quadriceps and VM exercise groups at 12months, this may not have necessarily been clinically important. This trial highlights that participant recruitment and retention are challenges which should be considered when designing future trials in this population. Level of evidence Therapeutic study, Level I


      PubDate: 2015-06-26T12:42:54Z
       
  • Contralateral limb deficit seven months after ACL-reconstruction: An
           analysis of single-leg hop tests
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Benoît Pairot de Fontenay , Sebastien Argaud , Yoann Blache , Karine Monteil
      Background Following ACL-reconstruction, the non-injured leg (NIL) is used as a reference to assess injured leg (IL) recovery. However, deficits have been reported in the NIL questioning its use as a reference. The aim of this study is to assess whether NIL deficits are present while jumping after ACL-reconstruction. Methods Thirteen males who had undergone ACL-reconstruction and 16 healthy subjects took part in the experiment. Jumping performance was assessed during a single and a triple hop for distance. Jumping performance, kinematic and kinetic data were recorded during single leg squat jumps. Values for both the NIL and the IL were compared to those of a control group (CG). Results Jumping performance for single and triple hop for distance and single leg squat jump was lower in the NIL than in the CG (p=0.004, p=0.002, and p=0.016, respectively). During the squat jump, the knee joint was more extended and the ankle plantar-flexion was greater at take-off while the peak total moment was 15% lower in the NIL than in the CG (p=0.002, p=0.002, and p=0.009, respectively). We found consistent evolutions in the NIL and the IL compared to the CG for jumping performance, initial joint angles, and peak total moment during the squat jump, but the opposite was found for the ankle and knee joint angles at squat jump take-off. Conclusions Jumping strategies are impaired in the NIL after ACL-R during jump tasks with some deficits matching those observed in the IL and some specific to the NIL. Level of evidence III, Case control study


      PubDate: 2015-06-26T12:42:54Z
       
  • Does adjustable-loop femoral cortical suspension loosen after anterior
           cruciate ligament reconstruction? A retrospective comparative study
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Matthew J. Boyle , Tyler J. Vovos , Cameron G. Walker , Kathryne J. Stabile , Jonathan M. Roth , William E. Garrett Jr.
      Background Recent biomechanical research has suggested that adjustable-loop graft suspension constructs in anterior cruciate ligament (ACL) reconstruction may loosen after deployment. Our objective was to compare short-term knee stability and graft failure rate between adjustable-loop and fixed-loop femoral cortical suspension in patients undergoing primary ACL reconstruction. Methods A consecutive series of 188 patients who underwent primary ACL reconstruction using hamstrings autograft by a single surgeon were divided into two groups; 73 received adjustable-loop (TightRope RT (Arthrex Inc., Naples, FL)) and 115 received fixed-loop (RetroButton (Arthrex Inc., Naples, FL)) femoral cortical suspension. The two groups were compared at six months, one year, and two years postoperatively using KT-1000 arthrometer testing and graft failure rate (revision surgery, grade 2+ Lachman test, any pivot shift, >5mm side-to-side KT-1000 difference). Results There was no significant difference between the two groups in maximum side-to-side difference in KT-1000 testing at six months (mean 1.51mm (adjustable-loop group) vs. 1.79mm (fixed-loop group), p=0.23), one year (mean 1.44mm vs. 1.64mm, p=0.48), or two years (mean 1.14mm vs. 1.07mm, p=0.90) postoperatively. There was no significant difference between the two groups in rate of graft failure (10% vs. 11%, p=0.71) or timing of graft failure in affected patients (mean 11.4months vs. 13.8months, p=0.51). Conclusions We found no significant difference in postoperative knee stability or graft failure rate between adjustable-loop and fixed-loop femoral cortical suspension in patients undergoing primary ACL reconstruction. Our results suggest that adjustable-loop suspension does not clinically loosen after ACL reconstruction. Level of Evidence III (retrospective cohort study)


      PubDate: 2015-06-26T12:42:54Z
       
  • Sex differences in unilateral landing mechanics from absolute and relative
           heights
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Joshua T. Weinhandl , Bobbie S. Irmischer , Zachary A. Sievert
      Background The prevalence of anterior cruciate ligament injuries in athletic populations and the sex disparity in injury rates are well documented. It is also recognized that landing from a jump is a common noncontact injury mechanism. Yet, most studies utilize absolute landing heights, and few have utilized landing heights equal to participants' maximal jumping ability. The purpose of this study was to examine unilateral landing mechanics from relative and absolute heights. Methods Twenty-one female and twenty male participants completed a series of landings from absolute heights of 30, 40, and 50cm, as well as a height equal to their maximum jumping ability. Right leg three-dimensional kinematics, kinetics, and energetics were calculated from initial contact to maximum knee flexion. Results Females landed with greater peak posterior ground reaction force compared to males. Additionally, both female and male participants utilized the knee as the primary energy absorber, but females appear to emphasize greater ankle energy absorption compared to males. Females also displayed increased peak knee adduction moment, while males displayed decreased peak hip abduction moment as landing height increased. Conclusions It appears that females and males respond to increasing landing heights differently. However, landings from 40 and 50cm may have represented an unrealistic mechanical demand for females, and influence subsequent inferences regarding ACL injury risk. Therefore, we suggest that comparisons between studies utilizing different landing heights be made with caution, and participants jumping ability be taken into account whenever possible. Clinical relevance The findings of this study offer novel insights with regard to landing height and lower extremity mechanics with the potential to inform anterior cruciate ligament injury intervention programs.


      PubDate: 2015-06-26T12:42:54Z
       
  • Calculation of external knee adduction moments: A comparison of an inverse
           dynamics approach and a simplified lever-arm approach
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Ryan T. Lewinson , Jay T. Worobets , Darren J. Stefanyshyn
      Background The external knee adduction moment (EKAM) is often studied in knee osteoarthritis research. This study compared EKAMs between two methods of calculation: a method that only requires ground reaction force and knee position data (i.e. lever-arm), and an inverse dynamics link-segment method. Methods Sixteen participants walked while wearing a control shoe with and without a six millimeter lateral wedge insole. Peak EKAMs between the lever-arm and inverse dynamics methods were compared for the control condition, and the %change in moment induced by the lateral wedge was compared between methods. Results When comparing EKAMs between methods, no correlation was found (r =0.24, p =0.36); peak EKAMs with the lever-arm method (26.0Nm) were significantly lower than EKAMs with the inverse dynamics method (40.2Nm, pb0.001); and Bland–Altman plots showed poor agreement between methods. When assessing the %change in moment with a lateral wedge, a moderate correlation was found (r =0.55, p =0.03) between methods; Bland–Altman plots showed moderate agreement between methods; and the lever-arm method (−6.4%) was not significantly different from the inverse dynamics method (−11.4%, p =0.09); however, the two methods produced opposite results 31% of the time. Conclusion The lever-arm method cannot estimate peak EKAMs, and can only approximate the %change in moment induced by a lateral wedge; however, the error rate was 31%. Therefore, the lever-arm method is not recommended for use in its current form. Clinical relevance This study may help guide the development of a fast and simple method for determining EKAMs for individuals with knee osteoarthritis.


      PubDate: 2015-06-26T12:42:54Z
       
  • The cost of adverse events from knee surgery in the United Kingdom: An
           in-depth review of the National Health Service Litigation Authority
           database
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): A. Chen , N.K. Patel , Y. Khan , J.P. Cobb , C.M. Gupte
      Background There has been a significant rise in the number and value of claims against the National Health Service (NHS), with limited studies on litigation in orthopaedic surgery and none in knee surgery alone. We aimed to examine claims against the NHS involving all aspects of knee surgery with respect to costs and trends. Clinical relevance To raise awareness of the reasons for litigation in knee surgery, thus potentially improve patient care and reduce future claims. Methods We analysed the NHS litigation authority (NHSLA) database for all orthopaedic surgery claims reported to the NHSLA between 2005 and 2010, with calculation of litigation success rates and odds ratios for those relating to knee surgery. Results There were 515 cases identified from the 4609 orthopaedic cases in the NHSLA database (11.2%): 298 (58%) involving total knee replacements (TKRs), 11 (2%) involving unicondylar knee replacements, and 90 cases (30%) remaining open. The total pay out for closed cases was £10.45 million and amputation following TKR resulted in the highest single pay out. Litigation success rates for claimants were highest for retained drains (100%), incorrect prosthesis/prosthesis size (78%), renal failure (75%), poor outcome requiring further surgery (74%) and malalignment (71%). There were also 60 cases of delayed diagnosis which resulted in pay outs totalling £2.90 million. Based on these data, projected future pay out costs for the open TKR cases were estimated to be £2.71 million. Conclusion Litigation success rates for TKR were highest following technical errors such as malalignment compared to events less under the surgeon's control, such as infection. The number of claims involving incorrect prosthesis/size continues to be of concern. Despite the increased availability of imaging modalities, missed diagnosis also resulted in substantial pay outs.


      PubDate: 2015-06-26T12:42:54Z
       
  • Return to activity among athletes with a symptomatic bipartite patella: A
           systematic review
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): George T. Matic , David C. Flanigan
      Background A bipartite patella is typically rare, but can become symptomatic during overuse activities such as those performed during athletic events. Therefore, this anomaly typically presents in the young, athletic population, often inhibiting athletic activities. Multiple treatment options exist, with nonsurgical management frequently adopted as the initial treatment of choice. Purpose To determine the most effective intervention in returning athletes with symptomatic bipartite patella to their prior activity levels. Methods A systematic review of the literature was performed using PRISMA guidelines to identify studies reporting outcomes of athletes' ability to return to activity following treatment for a symptomatic bipartite patella. The type of intervention, type of bipartite classification, outcomes, and complications were recorded. Results Twenty articles with a total of 125 patients and 130 knees were identified and included in this review. A total of 105 athletes made a full return to athletic activity following treatment for their painful bipartite patella. One hundred athletes (85.5%) that underwent surgical treatment were able to make a full return to their sport without symptoms, although this varied by surgical procedure performed. Excision of the painful fragment produced the best results in returning athletes to sport, with 91% returning without symptoms and nine percent returning but with residual symptoms. Conclusion Surgical treatments for symptomatic bipartite patellae are successful at returning athletes to their same level of play, and best outcomes are with excision of the fragment. These results are limited, however, due to the poor quality of original data given the rarity of the anomaly and the underrepresented conservative treatment group.


      PubDate: 2015-06-26T12:42:54Z
       
  • Contents List
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4




      PubDate: 2015-06-26T12:42:54Z
       
  • Editorial Board
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4




      PubDate: 2015-06-26T12:42:54Z
       
  • Editorial
    • Abstract: Publication date: September 2015
      Source:The Knee, Volume 22, Issue 4
      Author(s): Caroline B. Hing , Jim B. Stiehl



      PubDate: 2015-06-26T12:42:54Z
       
 
 
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