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The Knee 
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ISSN (Print) 0968-0160
Published by Elsevier
[2556 journals]
[9 followers] Follow Subscription journalISSN (Print) 0968-0160
Published by Elsevier
[2556 journals]- An analysis of dislocation of the domed Oxford Lateral Unicompartmental Knee Replacement
- Abstract: Publication date: Available online 12 May 2013
Source:The Knee
Author(s): J.S. Weston-Simons , B.J.L. Kendrick , M.J.A. Mentink , H. Pandit , H.S. Gill , D.W. Murray
Background The Oxford Unicompartmental Knee Replacement (OUKR) uses a mobile bearing to minimise wear. Bearing dislocation is a problem in the lateral compartment as the ligaments are loose in flexion. A domed tibial component has been introduced to minimise the risk of dislocation, yet they still occur, particularly medially. The aim of this mechanical study was to compare the domed and flat tibial components and to identify surgical factors that influence the risk of dislocation. Method A jig was constructed to assess the amount of vertical distraction of the lateral OUKR for a dislocation to occur. Three methods of dislocation were assessed: laterally, medially, 'over the wall' and anteriorly. The study focused on medial dislocation. Results Significantly (p=0.02) greater vertical distraction was required to dislocate the bearing with the domed tibia rather than the flat. For medial dislocation bearing distance from the wall, femoral component external rotation and tibial rotation were associated with significantly less distraction for dislocation. With the optimal technique with the domed tibia the distraction required to dislocate the bearing medially was 6.4mm, whereas with poor technique it was 4.6mm. Conclusions This study suggests that to minimise the risk of dislocation the domed tibia should be used. The component should be implanted so the bearing is close to the wall, but does not hit it, and in flexion the femoral and tibial components should be neutrally aligned.
PubDate: 2013-05-14T08:10:58Z
- Abstract: Publication date: Available online 12 May 2013
- Characterization of the orientation and isometry of Humphrey's ligament
- Abstract: Publication date: Available online 6 May 2013
Source:The Knee
Author(s): Michael B. Cross , Bradley S. Raphael , Travis G. Maak , Christopher Plaskos , Claus C. Egidy , Andrew D. Pearle
Objectives/purpose The purpose of this study was to examine the effect of flexion angle on isometry and fiber obliquity of the anterior meniscofemoral ligament (Humphrey's ligament (HL)). Methods Following a medial parapatellar arthrotomy on 7 fresh frozen cadavers, the insertion points of the anterolateral (AL) and posteromedial (PM) bundles of the PCL, and HL were identified. Using a 9mm circular software tool, virtual fibers were created. Within each virtual graft, a central fiber was calculated and used to generate anisometry profiles for the AL and PM bundles and HL at flexion angles of 0°, 30°, 60°, 90°, and 120°. Previously validated computer navigation software was used to re-create three dimensional bundles to measure fiber obliquity in the sagittal, frontal, and axial planes. Results HL length increased with knee flexion from 0 to 120°, and underwent similar length changes as the PCL bundles. In full extension and at 90°, the average length of the PM and AL bundles were not statistically different (p=0.13 and p=0.85 respectively). From 0 to 120°, the PM bundle was the most isometric, but the anisometry profile was statistically similar to the AL bundle and HL. In general, HL and the PM bundle had similar graphic trends in terms of fiber obliquity in all planes. Conclusions Using computer navigation, we have demonstrated that HL has similar isometry profiles as the PM and AL bundles of the PCL, and “mirrored” the obliquity of the PM bundle in all planes throughout flexion to 120°.
PubDate: 2013-05-10T08:10:39Z
- Abstract: Publication date: Available online 6 May 2013
- Time between the first and second operations for staged total knee arthroplasties when the interval is determined by the patient
- Abstract: Publication date: Available online 9 May 2013
Source:The Knee
Author(s): Yoshinori Ishii , Hideo Noguchi , Mitsuhiro Takeda , Junko Sato , Shin-Ichi Toyabe
Background The purpose of this study was to evaluate the interval between the first and second operations for staged total knee arthroplasties (TKAs) in patients with bilateral knee osteoarthritis. Depending on satisfactory preoperative health status, the patients determined the timing of the second operation. We also analysed correlations between the interval and patient characteristics. Methods Eighty-six patients with bilateral knee osteoarthritis were analysed. The mean follow-up time from the first TKA was 96months. The side of the first TKA was chosen by the patients. The timing of the second TKA was determined by the patients, depending on their perceived ability to tolerate the additional pain and limitations to activities of daily living. Results The median interval between the first and second operations was 12.5months, with a range of 2 to 113months. In 43 (50%) patients, the interval was <12months. There was no difference in the interval between females and males (p =0.861), and no correlation between the interval and body mass index or age. There was weak correlation between the year of the first TKA and the interval (R =−0.251, p =0.020), with the interval getting significantly shorter as the years progressed (p =0.032). Conclusions The median interval between the first and second operations in patients who underwent staged TKAs for bilateral knee osteoarthritis was about 1year. The results of the current study may help patients and physicians to plan effective treatment strategies for staged TKAs. Levels of evidence Level II.
PubDate: 2013-05-10T08:10:39Z
- Abstract: Publication date: Available online 9 May 2013
- Clinical and radiological results of femoral head structural allograft for severe bone defects in revision TKA — A minimum 8-year follow-up
- Abstract: Publication date: Available online 9 May 2013
Source:The Knee
Author(s): Churl Hong Chun , Jeong Woo Kim , Sung Hun Kim , Bong Gyu Kim , Keun Churl Chun , Kwang Mee Kim
Background Proper treatment of bone loss is essential for the long term durability of revision TKA. However, the method of choice in managing large bone defects is still under debate. We therefore assessed the mid to long term clinical and radiographic results of revision TKA using a fresh frozen femoral head allograft and a standard condylar implant or varus–valgus constrained prosthesis with a diaphyseal-engaging stem. Methods We retrospectively reviewed the records of 27 patients who had undergone revision TKA between August 1997 and March 2003 using a fresh frozen femoral head allograft and a standard condylar implant or varus–valgus constrained prosthesis with a diaphyseal-engaging stem. The median follow-up period was 107months (range, 96–157months). Results Clinical evaluation revealed that the mean range of motion had increased from 71° to 113° and the mean Hospital for Special Surgery knee score had improved from 46 to 83 points. The overall tibio-femoral angle improved from varus 7.3° to valgus 6.l°. In 26 out of 27 knees, union was demonstrated at an average of seven months postoperatively, and there were no cases of collapse, disease transmission or stress fractures. In one knee, an infection recurred. Conclusions Our results demonstrate that femoral head allografts in treatment of severe bone defects are reliable and durable. If possible, less constrained prostheses with diaphyseal-engaging stems should be chosen for increased durability. Level of evidence Level IV, therapeutic study. See Guidelines for
Authors for a complete description of levels of evidence.
PubDate: 2013-05-10T08:10:39Z
- Abstract: Publication date: Available online 9 May 2013
- Post-operative complications following primary ACL reconstruction using allogenic and autogenic soft tissue grafts: Increased relative morbidity risk is associated with increased graft diameter
- Abstract: Publication date: Available online 9 May 2013
Source:The Knee
Author(s): Dennis C. Crawford , Sara E. Hallvik , Ryan C. Petering , Samantha M. Quilici , Loren O. Black , Stephanie A. Lavigne , Jodi Lapidus , Lynn M. Marshall
Background The purpose of this study is to compare the risk of peri-operative complication events associated with allogenic and autogenic grafts during routine follow-up for six months after primary arthroscopic anterior cruciate ligament (ACL) reconstruction surgery. Methods A retrospective cohort study identified patients that underwent ACL reconstruction via an arthroscopically assisted single tunnel technique. Fixation was primarily cortical suspension (endobutton) from the femora and bicortical fixation (Washer-loc) in the tibia. Patients were monitored for six months following surgery. Morbidity was defined as complications during this period requiring medical or surgical intervention. Risk of complications was compared according to tissue type and patient characteristics. The Cochran–Mantel–Haenszel method was applied to estimate risk ratios (RR) and confidence intervals (CI) as the measure of association between graft type and morbidity risk. Results The cohort included 413 eligible patients. Sixty six percent received allograft tissue, while the remainder received autograft tissue. Morbidity risk was 7.0% among patients receiving allograft tissue and 2.8% among patients receiving autograft tissue. Allograft demonstrated elevated risk of complication versus autograft (RR=2.3 (95% CI: 0.9–7.2)), though the data are of borderline significance (p=0.11). Complications were associated with larger graft diameter in comparison to patients who experienced no complication (9.0+/−1.2 mm v. 8.4+/−1.0mm, p=0.005). Conclusion The relative morbidity risk was about two-fold greater among patients receiving allograft tissue. Regardless of tissue type, graft size was larger among patients who experienced a complication. Level of evidence Level III.
PubDate: 2013-05-10T08:10:39Z
- Abstract: Publication date: Available online 9 May 2013
- Pain control after primary total knee replacement. A prospective randomised controlled trial of local infiltration versus single shot femoral nerve block
- Abstract: Publication date: Available online 9 May 2013
Source:The Knee
Author(s): Anam Ashraf , Videsh V. Raut , Stephen J. Canty , George J. McLauchlan
Background We report a prospective blinded randomised trial of local infiltration versus femoral nerve block in patients undergoing primary total knee replacement (TKR), in accordance with the CONSORT statement 2010. Methods Fifty patients in a teaching hospital were consented for the study. The study arms were intraoperative local anaesthesia (150ml 0.2% ropivacaine/1ml 1:1000 adrenaline/30mg ketolorac) and femoral nerve block (30ml 0.2% ropivacaine) with a primary outcome of pain score at 4h post operatively. Secondary outcomes were pain at 2h, pain scores before and after physiotherapy on day one, total opiate administered, time to physiotherapy goals and length of stay. Randomisation was by sealed envelope. The assessor was blinded and the patients partially blinded to the intervention. Results Ten patients were excluded, eight before randomisation. The trial is complete. Forty patients were analysed for the primary outcome measure. The local infiltration group had significantly lower pain scores at 4h post-operatively; mean [SD] score 2.1 [2.6] versus 6.8 [3.2], p <0.00001 and on post-operative day one prior to physiotherapy; mean score 2.4 [2.3] versus 4.4 [2.3], p <0.05. Total opiate use was also significantly lower in the local infiltration group; mean total 115 [50.3]mg versus 176.5 [103.5]mg, p <0.01. There was no difference in any other outcome. There were no harms as a result of either intervention. Conclusion Intraoperative local infiltration gives superior pain relief compared to single shot femoral nerve block over the first 24h following primary TKR and minimises post-operative opiate use.
PubDate: 2013-05-10T08:10:39Z
- Abstract: Publication date: Available online 9 May 2013
- AM bundle controls the anterior–posterior and rotational stability to a greater extent than the PL bundle — A cadaver study
- Abstract: Publication date: Available online 4 May 2013
Source:The Knee
Author(s): Martin Komzák , Radek Hart , František Okál , Adel Safi
Background The purpose of this study was to evaluate the influence of both bundles of the anterior cruciate ligament (ACL) on knee stability, anterior–posterior translation (APT) and internal (IR) and external (ER) rotation in cadaveric knees using a computer navigation system. Methods The APT, IR, and ER of the knees were recorded in the intact condition, the anterolateral bundle (AM) or the posterolateral bundle (PL) deficit condition and in the ACL-deficient condition. The KT-1000 arthrometer was used for APT evaluation. The measurement of rotational movements was done using a rollimeter. All tests were performed at 30°, 60° and 90° of flexion. Results At 30° of flexion: In the intact knee APT was 5.8mm, IR 12.1°, ER 10.1°. After the AM was cut, the APT increased to 9.1mm, IR to 13.9° and ER to 12.6°. After the PL was cut, the APT was 6.4mm, IR 13.1° and ER 10.6°. After the AM and PL were cut, the APT was 10.8mm, IR 15.7° and the ER was 12.9° on average. Conclusions The AM has a greater impact on the APT than the PL in all knee joint flexion angles. The PL does not resist the rotational stability more than the AM. The rotational stability is better controlled by both bundles of ACL as compared to one bundle of the ACL. Clinical Relevance This study acknowledges the fact that the both bundles of the ACL are importants for AP and rotational stability of the knee joint.
PubDate: 2013-05-06T08:11:54Z
- Abstract: Publication date: Available online 4 May 2013
- Single-stage cartilage repair in the knee with microfracture covered with a resorbable polymer-based matrix and autologous bone marrow concentrate
- Abstract: Publication date: Available online 30 April 2013
Source:The Knee
Author(s): D. Enea , S. Cecconi , S. Calcagno , A. Busilacchi , S. Manzotti , C. Kaps , A. Gigante
Background Different single-stage surgical approaches are currently under evaluation to repair focal cartilage lesions. This study aims to analyze the clinical and histological results after treatment of focal condylar articular lesions of the knee with microfracture and subsequent covering with a resorbable polyglycolic acid/hyaluronan (PGA -HA) matrix augmented with autologous bone marrow concentrate (BMC). Methods Nine patients with focal lesions of the condylar articular cartilage were consecutively treated with arthroscopic PGA -HA-covered microfracture and bone marrow concentrate (PGA -HA-CMBMC). Patients were retrospectively assessed using standardized assessment tools and magnetic resonance imaging (MRI). Five patients consented to undergo second look arthroscopy and 2 consented biopsy harvest. Results All the patients but one showed improvement in clinical scoring from the pre-operative situation to the latest follow-up (average 22±2months). The mean IKDC subjective score, Lysholm score, VAS and the median Tegner score significantly increased from baseline to the latest follow-up. Cartilage macroscopic assessment at 12months revealed that one repair appeared normal, three almost normal and one appeared abnormal. Histological analysis proofed hyaline-like cartilage repair tissue formation in one case. MRI at 8 to 12months follow-up showed complete defect filling. Conclusions The first clinical experience with single-stage treatment of focal cartilage defects of the knee with microfracture and covering with the PGA -HA matrix augmented with autologous BMC (PGA -HA-CMBMC) suggests that it is safe, it improves knee function and has the potential to regenerate hyaline-like cartilage. Level of evidence IV, case series.
PubDate: 2013-05-02T09:30:39Z
- Abstract: Publication date: Available online 30 April 2013
- Fractography and oxidative analysis of gamma inert sterilized posterior-stabilized tibial insert post fractures: Report of two cases
- Abstract: Publication date: Available online 28 April 2013
Source:The Knee
Author(s): Farzana Ansari , Jennifer Chang , James Huddleston III , Douglas Van Citters , Michael Ries , Lisa Pruitt
Background Highly crosslinked ultra-high molecular weight polyethylene (UHMWPE) has shown success in reducing wear in hip arthroplasty but there remains skepticism about its use in Total Knee Replacement (TKR) inserts that are known to experience fatigue loading and higher local cyclic contact stresses. Methods Two Legacy Posterior-Stabilized (LPS) Zimmer NexGen tibial implants sterilized by gamma irradiation in an inert environment with posts that fractured in vivo were analyzed. Failure mechanisms were determined using optical and scanning electron microscopy along with oxidative analysis via Fourier Transform Infra-Red (FTIR) spectroscopy. Results Micrographs of one retrieval revealed fatigue crack initiation on opposite sides of the post and quasi-brittle micromechanisms of crack propagation. FTIR of this retrieval revealed no oxidation. The fracture surface image of the second retrieval indicated a brittle fracture process and FTIR revealed oxidation in the explant. Conclusions These two cases suggest that crosslinking of UHMWPE as a manufacturing process or sterilization method in conjunction with designs that incorporate high stress concentrations, such as the tibial post, may reduce material strength. Moreover, free radicals generated from ionizing radiation can render the polymer susceptible to oxidative embrittlement. Clinical relevance Our findings suggest that tibial post fractures may be the results of in vivo oxidation and low level crosslinking. These and previous reports of fractured crosslinked UHMWPE devices implores caution when used with high stress concentrations, particularly when considering the potential for in vivo oxidation in TKR.
PubDate: 2013-05-02T09:30:39Z
- Abstract: Publication date: Available online 28 April 2013
- British Association for Surgery of the Knee
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Instructions for Authors
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Medial extrusion of the posterior segment of medial meniscus is a sensitive sign for posterior horn tears
- Abstract: Publication date: Available online 25 April 2013
Source:The Knee
Author(s): Tsuyoshi Ohishi , Daisuke Suzuki , Kazufumi Yamamoto , Tomohiro Banno , Yuta Shimizu , Yukihiro Matsuyama
Background To evaluate medial extrusion of the posterior segment of the medial meniscus in posterior horn tears. Methods This study enrolled 72 patients without medial meniscal tears (group N), 72 patients with medial meniscal tears without posterior horn tears (group PH−), 44 patients with posterior horn tears of the medial meniscus (group PH+). All meniscal tears were confirmed by arthroscopy. Medial extrusion of the middle segment and the posterior segment was measured on coronal MRIs. Results Extrusions of both middle and posterior segments in groups PH− and PH+ (middle segment; 2.94±1.51mm for group PH− and 3.75±1.69mm for group PH+, posterior segment; 1.85±1.82mm for group PH− and 4.59±2.74mm for group PH+) were significantly larger than those in group N (middle segment; 2.04±1.20, posterior segment; 1.21±1.86). Both indicators of extrusion in group PH+ were larger than those in group PH−. In the early OA category, neither middle nor posterior segment in group PH− extruded more than in group N. However, only the posterior segment in group PH+ extruded significantly more than in group N. Multiple lineal regression analyses revealed that posterior segment extrusion was strongly correlated with the posterior horn tears (p<0.001) among groups PH− and PH+. Conclusion The newly presented indicator for extrusion of the posterior segment of the medial meniscus is associated with posterior horn tears in comparison with the extrusion of the middle segment, especially in the early stages of osteoarthritis. Level of Evidence Level II - Diagnostic Study
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: Available online 25 April 2013
- 27year survival of Maney Watt unicondylar hemi knee replacement for fixation of a lateral tibial plateau fracture — a case report
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): R.S. Khakha , J.R. Gibbs , H. Chissell
We report the case of a 62-year-old gentleman who underwent a novel treatment for a lateral tibial plateau fracture 27years ago. The patient presented to an elective knee outpatient clinic with new onset knee pain. Further investigation revealed that this was a Maney Watt prosthesis (Zimmer UK) for use in the management of unicompartmental osteoarthritis. This mode of fixation gave this patient over 20years of good functional outcome. Following revision, the patient was followed up at 5years, reporting a satisfactory outcome.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- BASK Travelling Fellowships
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Mortality and perioperative complications after unicompartmental knee arthroplasty
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Michael J. Morris , Ryan G. Molli , Keith R. Berend , Adolph V. Lombardi Jr.
Aim of study Unicompartmental knee arthroplasty (UKA) has been increasingly utilized over the past decade secondary to favorable reports of better range of motion, higher activity levels, and increased patient satisfaction compared with total knee arthroplasty (TKA). The aim of this study was to determine the 90-day incidence of perioperative complications and mortality of patients undergoing UKA. Methods One thousand consecutive UKA in 828 patients were retrospectively reviewed. A retrospective review was performed to evaluate 90-day perioperative complication and mortality rates. Results There were zero deaths during the study period. Twelve percent of surgeries were complicated by variances within the 90-day postoperative period. There was one deep venous thrombosis (0.1%) and no pulmonary emboli. Cardiovascular complications were infrequent. Three patients had a myocardial infarction (0.31%), one developed congestive heart failure (0.1%), one angina (0.1%), and three had arrhythmias (0.31%). Secondary procedures were performed in 15 patients during the follow-up period: seven were manipulations under anesthesia for arthrofibrosis, one was an arthroscopic removal of retained cement, one arthroscopic removal of a drain, one repeat wound closure after a dehiscence secondary to a fall, one open reduction internal fixation for a supracondylar femur fracture, three irrigation and debridement procedures for an aseptic hematoma, and one radical debridement with later successful conversion to a total knee arthroplasty for a periprosthetic infection. Conclusion This study supports the notion that UKA is a safe procedure that is associated with a low rate of mortality and serious post-operative complications. Level of evidence Level IV, therapeutic study case series.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Non-invasive measurement of the patellofemoral movements during knee extension–flexion: A validation study
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Roy T.H. Cheung , Nicola W. Mok , Polly Y.M. Chung , Gabriel Y.F. Ng
Background This study compared the difference between patellofemoral kinematics derived simultaneously from patellar bone pin and skin sensors during full range of tibiofemoral joint movement. Methods Movements at the tibiofemoral and patellofemoral joints during passive full extension–flexion of the knees in three un-embalmed human cadavers were studied with four electromagnetic tracking sensors at a sampling rate of 30Hz. A total of four sensors were attached on distal femur, proximal tibia, the surface of a tailor-made patella mold and at the tip of a plastic bone pin planted in the patellar body through a window on the mold. Paired-sample Wilcoxon signed rank test was used to compare peak motions computed from different sensors. The correlation of the movement–time curves derived from different sensors was tested by coefficient of multiple correlations (CMC) in different sections of tibiofemoral joint range. Results Peak motions detected by skin sensor for patellar lateral tilt (p=0.045), distal translation (p=0.021), lateral shift (p=0.032), and anterior–posterior shift of patella (p=0.03 and 0.01 respectively) were higher than that by the bone pin sensor. The overall CMC values for anterior–posterior translation and medial–lateral shift were lower than movements in other planes of movement. The CMC values in initial range were higher than that in the middle and end range in all planes of movement. Conclusions Patellofemoral kinematics derived from skin sensors may not be representative of the underlying patellar motion. Kinematics reported from the skin sensors should be carefully interpreted.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Pre-operative quadriceps strength predicts IKDC2000 scores 6months after anterior cruciate ligament reconstruction
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): David Logerstedt , Andrew Lynch , Michael J. Axe , Lynn Snyder-Mackler
Level of evidence Level II. Background Quadriceps strength deficits are ubiquitous after anterior cruciate ligament (ACL) injury. Deficits prior to surgery can influence knee function post-operatively. Inhibition contributes to quadriceps strength deficits after an ACL injury. Body mass index, meniscal injury, and sex influence functional outcomes after ACL reconstruction. The purpose of this study is to examine the relationship of pre-operative quadriceps strength and post-operative knee function and to investigate how other pre-operative factors may influence this relationship. Methods After an ACL injury, subjects received pre-operative rehabilitation and performed quadriceps strength testing. Subjects underwent reconstruction and post-operative rehabilitation. Six months after ACL reconstruction, subjects completed the International Knee Documentation Committee 2000 subjective form (IKDC2000). Linear regression models were developed using IKDC2000 scores at 6months after ACL reconstruction as the dependent variable. Results Fifty-five subjects had complete pre-operative data and IKDC2000 scores at 6months after ACL reconstruction. Pre-operative involved quadriceps strength was a significant predictor for IKDC2000 scores 6months after ACL reconstruction. Sex, meniscal injury, pre-operative BMI, and pre-operative involved quadriceps activation ratio were not significant predictors in the regression model. Conclusions Pre-operative quadriceps strength can predict IKDC2000 scores 6months after ACL reconstruction. Deficits in pre-operative quadriceps strength influence self-reported function 6months after surgery. Factors that are known to influence quadriceps strength and self-reported outcomes do not influence the relationship between pre-operative quadriceps strength and post-operative IKDC2000 scores.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- ACL reconstruction: Effect of bone dowel on tibial tunnel enlargement
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Alcindo Silva , Ricardo Sampaio , Elisabete Pinto
Purpose To evaluate prospectively if the impaction of a bone dowel in the tibial tunnel prevents the tunnels from enlarging beyond their original diameter. Methods Seventeen patients underwent arthroscopically assisted ACL reconstruction with hamstring autologous graft. All patients underwent CT of the knee on the day of surgery, at 3months and 12months post-op. Results On the day of surgery, the median cross-sectional areas of the tunnels were 77.0 and 79.0mm2, respectively at 15mm and 20mm from the tip of the posterior wall of the tunnel. At 3months, the median cross-sectional areas of the tunnels were 70.0 and 65.0mm2, at 15mm and 20mm. At 12months post-op, the median cross-sectional areas of the tunnels were 69.0 and 69.0mm2. The median enlargement of the tunnels between 3months and 12months post-op was 0.0mm2 at 15mm and −2.0mm2 at 20mm. Conclusions The impaction of an autologous bone dowel in the tibial tunnel during hamstring ACL reconstruction keeps the tunnels from enlarging beyond their original diameter, and there is no further enlargement of the tunnels after 3months post-op.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Letter to the Editor
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Michael Ries , Simon Donell , Henry D. Clarke
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Letter to the Editor
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Michael Ries , Simon Donell
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- A systematic review to determine the reliability of knee joint position sense assessment measures
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Toby O. Smith , Leigh Davies , Caroline B. Hing
Background The assessment of joint position sense (JPS) is the most widely used measurement of knee proprioceptive capability within the literature. However, it remains unclear what the most reliable method is to assess this. The purpose of this study was to determine the intra- and inter-rater reliability of the various methods used to assess knee JPS. Methods A systematic review of published and unpublished literature sources was conducted up to June 2012. All studies principally assessing the reliability (intra- or inter-rater) or reproducibility of a JPS of the knee were included. The methodological quality of each study was reviewed using the Critical Appraisal Skills Programme tool. Results A total of 18 studies were eligible, assessing the reliability of JPS with 456 knees. The reliability of four methods of JPS has been recorded: position replication using a model, image recorded angulation, electrogoniometry and dynamometry/angular motion chair. Intra-rater reliability was good for the assessment of JPS using photographs and digital images, and replicating knee position using a paper model, this was good but variable when electrogoniometry was used, and moderate but variable when assessed using dynamometry/angle motion chairs. The assessment of JPS by image recorded angulation, electrogoniometry and dynamometry/angular motion chair has demonstrated good inter-rater reliability. Conclusions Whilst JPS methods appear to have variable reliability, the four assessment methods should be further assessed with pathological populations such as those following patellar dislocation or anterior cruciate ligament rupture. This will better facilitate the generalisability of JPS assessment methods to inform clinical practice.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Examining internet resources on gender differences in ACL injuries: What patients are reading
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Michelle M. Gosselin , Mary K. Mulcahey , Edward Feller , Michael J. Hulstyn
Background The Internet is a popular and powerful resource used by both clinicians and patients. However, medical information on the Internet is often unregulated, biased, and of poor quality. Given the frequency of ACL injuries in young women, this topic was used as a case study to examine the information available to patients on the Internet. Methods An Internet search was performed using the top three general search engines for four different search phrases related to ACL injuries in females. The top ten sites from each search were analyzed on the basis of both website interface and a specific content scoring guide. Results A total of 35 unique websites were analyzed. The majority of websites were authored by a layperson or had an unidentified author. Readability data indicated that many sites were written at literacy levels that were too difficult for the average reader. Finally, the average content analysis score for all sites was 41.6 out of a possible 100 points (range 10–87.5); only one-third of the websites cited references for the information provided. Conclusions We found the Internet information on ACL injuries in women to be largely unsupported, outdated and too difficult for the average reader to comprehend. The average site covered less than half of the topics that we considered relevant to ACL injuries in females indicating that information available on the Internet is largely incomplete. Clinical relevance Clinicians should be aware of the deficiencies in Internet information in order to appropriately address these issues with patients.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Influence of preparation techniques to the strength of the bone–cement interface behind the flange in total knee arthroplasty
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): S.A.W. van de Groes , M.C. de Waal Malefijt , N. Verdonschot
Introduction Recent clinical studies show an increased risk of femoral loosening in high-flexion TKA. Loosening seems to occur behind the anterior flange, which is covering both cancellous bone and cortical bone. It is important to optimize the interface strength between cement and both bone types to increase femoral component fixation. This study was performed to determine the cement–cortical bone interface strength for different preparation techniques. Material and methods A pure tensile and shear force was applied to interface specimens. The cortical surface area was prepared in three different ways: (1) Unprepared cortical bone with periosteum; (2) Periosteum removed and cortical bone roughened with a rasp; (3) Periosteum removed and three Ø3.2mm holes drilled through the cortex. A reference group was added with a cancellous bone surface. Results The interface tensile strength of Group 1 was 0.06MPa and the shear strength was 0.05MPa. For Group 2, respectively 0.22MPa and 1.12MPa. For Group 3, respectively 1.15MPa and 1.77MPa. For cancellous bone a tensile strength of 1.79MPa and a shear strength of 3.85MPa were measured. Conclusion The strength of the cement–cancellous bone interface is superior to the cement–cortical bone interface. The preferred preparation technique of the cortical bone is to remove all the periosteum and drill holes through the cortex within the footprint of the anterior flange, to prevent cortical weakening. Clinical relevance Ultimately, the proposed preparation technique will lead to longer implant survival, particularly for prostheses which are used in the high-flexion range.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- The effect of playing surface on the incidence of ACL injuries in National Collegiate Athletic Association American Football
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Jason L. Dragoo , Hillary J. Braun , Alex H.S. Harris
Background Artificial playing surfaces are widely used for American football practice and competition and anterior cruciate ligament (ACL) injuries are common. This study analyzed the National Collegiate Athletic Association (NCAA) Injury Surveillance System (ISS) men's football ACL injury database from 2004–2005 through 2008–2009 to determine the effect of playing surface on ACL injury in NCAA footballathletes. Methods This database was reviewed from the 2004–2005 through 2008–2009 seasons using the specific injury code, “Anterior cruciate ligament (ACL) complete tear.” The injury rate was computed for competition and practice exposures. Ninety-five percent confidence intervals were calculated using assumptions of a Poisson distribution. Pair-wise, two-sample tests of equality of proportions with a continuity correction were used to estimate the associations of risk factors. Results There was an incidence rate of 1.73 ACL injuries per 10,000 athlete-exposures (A-Es) (95% CI 1.47–2.0) on artificial playing surfaces compared with a rate of 1.24 per 10,000 A-Es (1.05–1.45, p<0.001) on natural grass. The rate of ACL injury on artificial surfaces is 1.39 times higher than the injury rate on grass surfaces. Non-contact injuries occurred more frequently on artificial turf surfaces (44.29%) than on natural grass (36.12%). Conclusions NCAA football players experience a greater number of ACL injuries when playing on artificial surfaces.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Incidence and severity of complications due to femoral nerve blocks performed for knee surgery
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Benjamin Widmer , Sébastien Lustig , Corey J. Scholes , Allen Molloy , Sean P.M. Leo , Myles R.J. Coolican , David A. Parker
Background: While single shot femoral nerve blocks and indwelling femoral nerve catheters provide significant peri-operative analgesia, there are small but serious risks of neurovascular complications. We aimed to determine the incidence and characterise the nature of neural complications arising from femoral nerve blocks performed for knee surgery. Methods: One thousand eight hundred and two patients receiving a femoral nerve block for knee surgery during the study period were screened. Patients with possible neurological symptoms were evaluated with a detailed physical examination and self-report questionnaires. Also measures of depression, anxiety and tension/stress were collected. Results: In the patients screened, an incidence of 1.94% was found. Of the 24 patients available for testing, 4 had bilateral symptoms following bilateral nerve blocks. All had sensory abnormalities in the distribution of the femoral nerve. The incidence was significantly higher in females (females=2.5%, males=0.83% p=0.01) and in patients receiving a single shot block (single shot=2.66%, femoral catheter=0.93, p=0.01). Conclusions: The incidence of neurological complication after FNB was higher in this series than typically reported and the symptoms significantly influenced the quality of life in the affected cases. The decision to include a femoral nerve block in the peri-operative analgesic regimen should be made on an individual basis considering the risks and benefits. Level of evidence Therapeutic level IV.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Venous thromboembolism and its prophylaxis in elective knee arthroplasty: An international perspective
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Arif Khokhar , Aswin Chari , David Murray , Martin McNally , Hemant Pandit
Introduction Patients undergoing knee arthroplasty are at high risk of developing post-operative deep vein thrombosis (DVT) or a pulmonary embolus (PE). Despite best efforts, the best prophylaxis for thromboembolic disease remains controversial. This article aims to update the reader on the newest guidelines concerning venous thromboembolism (VTE) prophylaxis for elective knee arthroplasty, highlighting their inconsistencies and why variations in recommendations exist. Methods The Medline database and the Internet were searched for VTE prophylaxis guidelines in English. 12 guidelines were found and compared. The comparison looked at the recommendations made, the grade of recommendation, the level of evidence available for these recommendations and any inconsistencies between the guidelines. Results Nearly all the guidelines advocate the use of low molecular weight heparin (LMWH) and Fondaparinux. There is little consensus in terms of other recommended drugs, the doses, duration and their recommendation grades. There are marked differences in the methodologies adopted by the different guideline working-groups. Conclusion There is still uncertainty about the optimal methods of thromboprophylaxis in elective knee arthroplasty. Although there are always going to be disagreements about the endpoints amongst guideline makers, guidelines should achieve uniformity in their reporting of end-points, criteria for levels of evidence and recommendation grades, facilitating the clinician's decision-making process. Level of evidence IIa.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Contents List
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Editorial Board
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Plagiarism in medical literature
- Abstract: Publication date: June 2013
Source:The Knee, Volume 20, Issue 3
Author(s): Jim Stiehl , Caroline Hing
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: June 2013
- Iliotibial band irritation caused by the EndoButton after anatomic double-bundle anterior cruciate ligament reconstruction: Report of two cases
- Abstract: Publication date: Available online 25 April 2013
Source:The Knee
Author(s): Shuji Taketomi , Hiroshi Inui , Jinso Hirota , Kensuke Nakamura , Takaki Sanada , Hironari Masuda , Sakae Tanaka , Takumi Nakagawa
Two patients underwent arthroscopic anatomic double-bundle anterior cruciate ligament (ACL) reconstruction using the EndoButton for femoral fixation. The femoral tunnels were created by the inside-out technique through a far anteromedial portal. The patients postoperatively developed moderate lateral knee pain without instability. At the second-look arthroscopic evaluation, the two EndoButtons were removed. Both patients were completely asymptomatic several months after implant removal, implying that the EndoButtons caused the mechanical irritation in the iliotibial band. This is the first report describing removal of EndoButtons because of pain caused by friction with the iliotibial band. In anatomic ACL reconstruction, if the femoral tunnel exit is positioned near the lateral femoral epicondyle, care should be taken to prevent iliotibial band friction syndrome that could result because of the EndoButton.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: Available online 25 April 2013
- Clinically insignificant association between anterior knee pain and patellofemoral lesions which are found incidentally
- Abstract: Publication date: Available online 25 April 2013
Source:The Knee
Author(s): D.W. Elson , S. Jones , N. Caplan , A. St Clair Gibson , S. Stewart , D.F. Kader
Background Patellofemoral chondral lesions are frequently identified incidentally during the arthroscopic treatment of other knee pathologies. A role has been described for arthroscopic debridement when symptoms are known to originate from pathology of the patellofemoral joint. However, it remains unclear how to manage lesions which are found incidentally whilst tackling other pathologies. The purpose of this study was to establish the strength of association between anterior knee pain and patellofemoral lesions identified incidentally in a typical arthroscopic population. Methods A consecutive series of patients undergoing arthroscopy for a range of standard indications formed the basis of this cross section study. We excluded those with patellofemoral conditions in order to identify patellofemoral lesions which were solely incidental. Pre-operative assessments were performed on 64 patients, where anterior knee pain was sought by three methods: an annotated photographic knee pain map (PKPM), patient indication with one finger and by palpated tenderness. A single blinded surgeon, performed standard arthroscopies and recorded patellofemoral lesions. Statistical correlations were performed to identify the association magnitude. Results Associations were identified between incidental patellofemoral lesions and tenderness palpated on the medial patella (P = 0.007, χ2 = 0.32) and the quadriceps tendon (P = 0.029, χ2 = 0.26), but these associations were at best fair, which could be interpreted as clinically insignificant. Conclusion Incidental patellofemoral lesions are not necessarily associated with anterior knee pain, we suggest that they could be left alone. This recommendation is only applicable to patellofemoral lesions which are found incidentally whilst addressing other pathology.
PubDate: 2013-04-28T08:13:06Z
- Abstract: Publication date: Available online 25 April 2013
- A method for assessing joint line shift post knee arthroplasty considering the preoperative joint space
- Abstract: Publication date: Available online 20 April 2013
Source:The Knee
Author(s): Shahram Amiri , Bassam A. Masri , Carolyn Anglin , David R. Wilson
Background Accurate comparison of outcomes regarding various surgical options in knee arthroplasty can benefit from an improved method for joint line analysis that takes into account the preoperative joint space. Methods This article describes a new preoperative-based registration method that measures changes in the joint line by overlaying the 3D models of the bones with implants using preoperative CT along with preoperative and postoperative biplanar radiography. The method was tested on six cadaveric specimens for measuring alteration to the medial and lateral joint lines in extension and flexion. Results The joint line shift, when measured using the new method, was in the range of −0.2 to 1.3mm on average (SD=1.3 to 3.8mm, for medial and lateral, in flexion and extension positions). This was significantly different (p≤0.01) from the results of a previous postoperative-based registration method which did not account for the cartilage thickness in calculating alterations of the joint line (mean=3.9 to 6.8mm, SD=1.2 to 4.3mm). Conclusion These results further highlight the importance of considering the preoperative joint space in analyzing the joint line, and demonstrate the utility of the newly introduced method for accurate assessment of changes in the joint line after arthroplasty. Clinical relevance The introduced method provides accurate means for investigating joint line alterations in relation to different surgical techniques and the subsequent biomechanical effects after knee arthroplasty
PubDate: 2013-04-20T08:06:27Z
- Abstract: Publication date: Available online 20 April 2013
- Parameniscal cyst formation in the knee is associated with meniscal tear size: An MRI study
- Abstract: Publication date: Available online 13 April 2013
Source:The Knee
Author(s): Chia-Chun Wu , Yi-Chih Hsu , Ying-Chun Chiu , Yue-Cune Chang , Chian-Her Lee , Hsain-Chung Shen , Guo-Shu Huang
Background The relationship between meniscal tears and parameniscal cyst formation is contentious. We investigated whether the development of a parameniscal cyst is related to the size of the meniscal tear by using magnetic resonance imaging (MRI). Methods On the basis of a retrospective review of an MRI database, we identified parameniscal cysts in 34 patients with adjacent meniscal tears extending to the meniscocapsular junction. The size of the meniscal tear was measured by dividing the length of the tear along two axes: circumferential and radial. We compared parameters, such as the size of the meniscal tear, the location of the tear, the pattern of each tear, and any associated ligamentous injury and intra-articular lesion, between the 34 patients and the 30 control patients who only had meniscal tears with torn components extending to the meniscocapsular junction. Results Compared with the controls, patients with parameniscal cysts had significantly larger meniscal tears along the circumferential axis (P <0.001). A critical size of the meniscal tear along the circumferential axis of 12mm was associated with the formation of a parameniscal cyst. Conclusions A larger meniscal tear extending into the meniscocapsular junction is more likely to be associated with the occurrence of a parameniscal cyst. The critical size of the meniscal tear, 12mm along the circumferential axis as identified using MRI, is a discrimination value for parameniscal cyst formation. Level of Eviden Level III
PubDate: 2013-04-16T06:32:21Z
- Abstract: Publication date: Available online 13 April 2013
- Posterior femoral condylar offsets of a Chinese population
- Abstract: Publication date: Available online 12 April 2013
Source:The Knee
Author(s): Wei Wang , Tsung-Yuan Tsai , Bin Yue , Young-Min Kwon , Guoan Li
Background The effect of posterior condylar offset (PCO) on maximal flexion of the knee after TKA is controversial. Another parameter, the posterior condylar offset ratio (PCOR), has been recently introduced to describe the posterior condylar geometry. This study measured the posterior femoral condyle geometry of a Chinese population and compared with those of a Western population published in the literature. Methods We measured the PCO and PCOR of 100 Chinese knees (50 males, 50 females). The distances from the anterior and posterior femoral shaft cortex line to the most posterior femoral condyle tangent line were defined as the anterior–posterior dimension (ACP) and posterior condylar offset (PCO). The PCOR was calculated as PCO/ACP. The measured PCO and PCOR were compared to those of a Western population reported in the literature. Results The PCOs were 25.80±2.71 and 27.32±2.34mm for the Chinese females and males, respectively, where the PCO of the females was significantly smaller than that of the males (p<0.05). The PCORs were 0.47±0.04 and 0.46±0.03 for the Chinese females and males, respectively, where the PCORs were similar among the Chinese males and females (p>0.05). Conclusions While the PCO of the Chinese females was smaller than that of the males, their PCORs were similar. Compared to the data of a Western population reported in literature, the PCO of the Chinese population is significantly smaller, but the PCOR is significantly larger.
PubDate: 2013-04-16T06:32:21Z
- Abstract: Publication date: Available online 12 April 2013
- Popliteal pseudoaneurysm after unicompartmental knee replacement: A case report
- Abstract: Publication date: Available online 12 April 2013
Source:The Knee
Author(s): Sergio Tejero-Garcia , Jose F. Lirola Criado , Michael P. Ast , Gabriel Domecq Fernandez de Bobadilla
Popliteal pseudoaneurysm is a rare but important complication of knee arthroplasties. To our knowledge, this complication has not been reported previously in the literature after unicompartmental knee arthroplasty. Apart from intraoperatively caused arterial injuries, obese patients and other previous cardiovascular diseases may be potential factors of risks for pseudoaneurysm in knee surgeries. As it is an uncommon complication and it has inconspicuous symptoms, both diagnosis and treatment can be delayed. This means that a high level of suspicion is necessary to prevent serious complications derived from pseudoaneurysms. Level of Eviden Level IV
PubDate: 2013-04-16T06:32:21Z
- Abstract: Publication date: Available online 12 April 2013
- Performance assessment of femoral knee components made from cobalt–chromium alloy and oxidized zirconium
- Abstract: Publication date: Available online 11 April 2013
Source:The Knee
Background The surface characteristics of the femoral component affect polyethylene wear in modular total knee replacements. In the present retrieval study, the surface characteristics of cobalt–chromium (CoCr) alloy and oxidized zirconium (OxZr) femoral components were assessed and compared. Methods Twenty-six retrieved CoCr alloy femoral components were matched with twenty-six retrieved OxZr femoral components for implantation period, body-mass index, patient gender, implant type, and polyethylene insert thickness. The surface damage on the retrieved femoral components was evaluated using a semi-quantitative assessment method, scanning electron microscopy, and contact profilometry. Results The retrieved CoCr alloy femoral components showed less posterior surface gouging than OxZr femoral components; however, at a higher magnification, the grooving damage features on the retrieved CoCr alloy femoral components confirmed an abrasive wear mechanism. The surface roughness values Rp, Rpm, and Rpk for the retrieved CoCr alloy femoral components were found to be significantly higher than those of the retrieved OxZr femoral components (p≤0.031). The surface roughness values were higher on the medial condyles than on the lateral condyles of the retrieved CoCr alloy femoral components; such a difference was not observed on the retrieved OxZr femoral components. Conclusions The surface roughness of CoCr alloy femoral components increased while the surface roughness of the OxZr femoral components remained unchanged after in vivo service. Therefore, the OxZr femoral components' resistance to abrasive wear may enable lower polyethylene wear and ensure long-term durability in vivo. Level of Evidence Level IV
PubDate: 2013-04-12T06:24:14Z
- Abstract: Publication date: Available online 11 April 2013
- Comparative biomechanical analysis of human and caprine knee articular cartilage
- Abstract: Publication date: Available online 9 April 2013
Source:The Knee
Background The goat is one of the most commonly used preclinical models for focal defect repair and regeneration. While the biomechanics of the human knee has been studied extensively, less is known about the biomechanics of the caprine knee. Differences between human and caprine knees have not been quantified and their significance is largely unknown. Methods We conducted a biomechanical analysis of the differences in goat and human knees to assess the validity of these preclinical in vivo models. Results CT and MRI scans revealed several differences in articular geometry: the caprine tibial plateaux were more convex and the menisci were significantly thicker and covered a larger proportion of the tibial articular surface. Caprine cartilage thickness was consistently thinner, while elastic modulus on indentation testing was consistently stiffer than human cartilage measured at eight different articular locations. Contact area and pressure were measured with electronic pressure sensors under loads normalized by multiples of body weight and at knee flexion angles reported for walking. The highest peaks in contact pressure were measured in the patellofemoral joint in goat and human knees. Peak contact pressure measured at 2 times body weight at the goat tibiofemoral joint at 70° flexion was significantly higher than for any other condition at the human tibiofemoral joint. Conclusion These differences in contact conditions might explain the lower quality of local repair reported for caprine femoral condylar defects relative to trochlear defects. Further comparative analysis, including biologic response, is necessary to determine the extent to which the goat knee reproduces clinical conditions.
PubDate: 2013-04-12T06:24:14Z
- Abstract: Publication date: Available online 9 April 2013
- Finite element comparison of retrograde intramedullary nailing and locking plate fixation with/without an intramedullary allograft for distal femur fracture following total knee arthroplasty
- Abstract: Publication date: Available online 10 April 2013
Source:The Knee
Purpose Periprosthetic distal femur fracture after total knee arthroplasty due to the stress-shielding phenomenon is a challenging problem. Retrograde intramedullary nail (RIMN) or locking plate (LP) fixation with/without a strut allograft has been clinically used via less invasive stabilization surgery (LISS) for the treatment of these periprosthetic fractures. However, their biomechanical differences in construct stability and implant stress have not been extensively studied, especially for the osteoporotic femur. Methods This study used a finite-element method to evaluate the differences between RIMN, LP, and LP/allograft fixation in treating periprosthetic distal femur fractures. There were sixteen variations of two fracture angles (transverse and oblique), two loading conditions (compression and rotation), and four bony conditions (one normal and three osteoporotic). Construct stiffness, fracture micromotion, and implant stress were chosen as the comparison indices. Results The LP/allograft construct provides both lateral and middle supports to the displaced femur. Comparatively, the LP and RIMN constructs, respectively, transmit the loads through the lateral and middle paths, thus providing more unstable support to the construct and high stressing on the implants. The fracture pattern plays a minor role in the construct stabilization of the three implants. In general, the biomechanical performances of the RIMN and LP constructs were comparable and significantly inferior to those of the LP/allograft construct. The bone quality should be evaluated prior to the selection of internal fixators. Conclusions The LP/allograft construct significantly stabilizes the fracture gap, reduces the implant stress, and serves as the recommended fixation for periprosthetic distal femur fracture.
PubDate: 2013-04-12T06:24:14Z
- Abstract: Publication date: Available online 10 April 2013
- Differences in knee joint kinematics and forces after posterior cruciate retaining and stabilized total knee arthroplasty
- Abstract: Publication date: Available online 8 April 2013
Source:The Knee
Background Posterior cruciate ligament (PCL) retaining (CR) and -sacrificing (PS) total knee arthroplasties (TKA) are widely-used to treat osteoarthritis of the knee joint. The PS design substitutes the function of the PCL with a cam-spine mechanism which may produce adverse changes to joint kinematics and kinetics. Methods CR- and PS-TKA were performed on 11 human knee specimens. Joint kinematics were measured with a dynamic knee simulator and motion tracking equipment. In-situ loads of the PCL and cam-spine were measured with a robotic force sensor system. Partial weight bearing flexions were simulated and external forces were applied. Results The PS-TKA rotated significantly less throughout the whole flexion range compared to the CR-TKA. Femoral roll back was greater in the PS-TKA; however, this was not correlated with lower quadriceps forces. Application of external loads produced significantly different in-situ force profiles between the TKA systems. Conclusions Our data demonstrate that the PS-design significantly alters kinematics of the knee joint. Our data also suggest the cam-spine mechanism may have little influence on high flexion kinematics (such as femoral rollback) with most of the load burden shared by supporting implant and soft-tissue structures.
PubDate: 2013-04-12T06:24:14Z
- Abstract: Publication date: Available online 8 April 2013
- In vivo degradation characteristics of bioabsorbable cross-pins in anterior cruciate ligament reconstruction
- Abstract: Available online 7 April 2013
Publication year: 2013
Source:The Knee
Background We evaluated degradation of bioabsorbable femoral cross-pins following anterior cruciate ligament (ACL) reconstruction. Methods Four patients underwent ACL reconstruction using hamstring autograft with femoral fixation provided by a polylactic acid/polyglycolic acid copolymer (LactoSorb L15) cross-pin. Serial computed tomography (CT) scans were performed of the reconstructed knees at approximately 6weeks, 4months, 1year and 2years, postoperatively. A radiologist evaluated the scans for density of pins and surrounding bone and pin morphology. Results The cross-pins demonstrated a relative reduction in density of 7.7%, 49.1%, and 75.0% at 4months, 1year and 2years, respectively. Bone density values adjacent to the pin decreased by an mean of 8.6% between 6weeks and 4months. At one year an additional 14.2% reduction in bone density was seen but at 2years the relative reduction in bone density had decreased to 7.4%. Evaluation of pin morphology revealed that minimal change had occurred after 6weeks. At 4months all of the pins were showing some morphologic changes on the surface, but none had fractured. After 1year, two of the pins had fractured. By 2years all of the pins had fractured. None of the pins had completely reabsorbed at 2years postoperatively. Conclusions LactoSorb L15 cross-pins for femoral fixation in ACL reconstruction remain largely unchanged 4months postoperatively, suggesting that this device maintains the necessary structural integrity to allow early integration of soft tissue grafts within bone tunnels. Level of evidence IV, case series.
PubDate: 2013-04-08T06:28:21Z
- Abstract: Available online 7 April 2013
- Does cruciate-retaining total knee arthroplasty enhance knee flexion in Western and East Asian patient populations' A meta-analysis
- Abstract: Available online 4 April 2013
Publication year: 2013
Source:The Knee
Introduction This study analyzed the published data to examine if CR TKAs can enhance the flexion and functional outcomes of the knee in the Western and East Asian populations using a meta-analysis approach. Materials and methods A systematic review of literature published through Medline and EMBASE was conducted. The inclusion criteria were: primary TKA, follow up duration greater than one year, a fixed bearing CR prosthesis, and data for maximum pre- and post-operative flexion along with standard deviations or errors. We estimated the weighted mean differences between pre- and post-operative flexion, extension and knee scores (KSS and HSS) via a random effect model. Results Seventeen articles were selected and reviewed among 1229 studies that included 1090 knees of the Western and 516 knees of the East Asian. No significant difference was noted in maximal knee flexion pre- and post-operatively, when all the studies were pooled together (−0.17°, p=0.93, post-operative<pre-operative). The mean difference in flexion was −1.87° (p=0.2) and 2.03° (p=0.17), respectively in the both populations. However, the extension angle was significantly improved by −5.49° and −13.05° (p<0.05), respectively. KSS scores were significantly improved by 46.39 and 51.63, and HSS scores by 36.65 and 30.67 (p<0.05), respectively in the both populations. Conclusion The meta-analysis indicated that contemporary CR TKAs have not been shown to enhance post-operative flexion capability in the Western and East Asian. The extension angles of the knee and the knee scores were significantly improved in both populations.
PubDate: 2013-04-08T06:28:21Z
- Abstract: Available online 4 April 2013
- Does infrapatellar fat pad resection in total knee arthroplasty impair clinical outcome' A systematic review
- Abstract: Available online 6 April 2013
Publication year: 2013
Source:The Knee
Introduction The infrapatellar fat pad (IPFP) is often removed during total knee arthroplasty (TKA). No evidence based guidelines on changes in clinical outcome have yet been described. The aim of this review is to investigate whether regular removal of the IPFP during TKA should be performed. Material and methods Seven databases were systematically searched. Clinical studies, in which TKA with IPFP resection was compared with IPFP preservation, were included. Risk of bias was assessed using the Cochrane collaboration tool. Studies reporting anterior knee pain, patellar tendon length, range of motion, patellar vascularisation or functional outcome were included. Results The indication for TKA varied in the different studies: osteoarthritis (OA), rheumatic arthritis (RA) and multiple indications (OA, RA and osteonecrosis). After IPFP resection: 1. For OA, no differences in function, range of motion, and anterior knee pain were found. 2. In the RA study, there was a trend towards more discomfort and a decrease in function. 3. In OA and RA patients a decrease in patellar tendon length was observed. 4. One study reported no decrease in patellar vascularisation. Discussion Limitations of this review are the high risk of bias scores of the included studies, the varying outcome measures, follow up, number and type of participants. Randomised clinical trials are required to support or refute the results, contributing to a possible future evidence based guideline on IPFP resection during TKA.
PubDate: 2013-04-08T06:28:21Z
- Abstract: Available online 6 April 2013
- The use of rivaroxaban for chemical thromboprophylaxis following total knee replacement
- Abstract: Available online 6 April 2013
Publication year: 2013
Source:The Knee
Background Pulmonary embolism is a leading cause of fatality in elective orthopaedics. Recently introduced oral thromboprophylaxis (rivaroxaban) has a logistic advantage but has also raised early concerns amongst arthroplasty surgeons Aim The aim of this study was to evaluate the impact of rivaroxaban as a chemical thromboprophylaxis following knee arthroplasty in reference to radiologically diagnosed PE and return to theatre following wound complication. Method Following the introduction of new NICE guidelines in our institute 266 consecutive TKR receiving rivaroxaban were studied prospectively and compared with retrospectively collected consecutive 596 TKR prior to adoption of the guidelines. Both of these groups were studied for radiologically diagnosed symptomatic VTE episodes within 90days and return to theatre following wound complication. Results A total of 862 cases were studied, out of which 596 were in the retrospective control group and 266 were in the prospective rivaroxaban group. Both the groups had a female predominance with a mean age at the time of surgery as 68 and 69 in control and prospective cohort respectively. There were 24 radiologically diagnosed symptomatic PE and one DVT in the control group whereas, the rivaroxaban prospective group had 2 PE and 2 DVT cases. The return to theatre following wound complication was 2 and 7 in control and prospective group respectively. Conclusion Following the introduction of rivaroxaban the number of symptomatic radiologically confirmed PE events declined (p=0.0084) but the return to theatre rate due to wound complications increased (p=0.0049). Level of evidence III.
PubDate: 2013-04-08T06:28:21Z
- Abstract: Available online 6 April 2013
- Is the posterior cruciate ligament destabilized after the tibial cut in a cruciate retaining total knee replacement' An anatomical study
- Abstract: Available online 6 April 2013
Publication year: 2013
Source:The Knee
Introduction/purpose Cruciate retaining total knee replacement has been shown to effectively improve pain and quality of life. Successful outcomes depend on many factors, including the maintenance of a competent posterior cruciate ligament. This study sought to anatomically analyze the percentage of PCL injured during a full transverse, tibial cut, thus altering normal function. Materials and methods One hundred and thirty five consecutive knee MRIs taken from 2006 to 2011 were selected from a single surgeon's database for this study. Only subjects with non-arthritic knees were considered for this study; the lack of degenerative joint disease (DJD) was confirmed via a radiological report. The optimal view of the PCL's tibial attachment was observed using the sagittal view of the knee, with a T1 signal. One hundred and twenty two usable images were viewed electronically, and measurements were made using the standardized transverse cut implant guidelines. The percentage of PCL remaining following the cut was categorized into five different groups: 0% (no PCL undermined), 1–49%, 50–74%, 75–99% and 100% (PCL undermined entirely). Results Overall only 9.0% (n =11) would have not endured any damage to the PCL with a transverse tibial saw cut, while 79.6% (n =98) would have had 50% or more of the PCL undermined. Of the 98 patients with more than 50% resected, 52.1% (n =51 patients) presented complete destabilization of the PCL. The percentage of PCL destabilized was not significant across age groups (p =0.280), gender (p =0.586), or operative side (p =0.460). Conclusion Independent of age, gender, and operative side, a majority of PCLs are more than 50% destabilized following the standard transverse tibial cut. Level of evidence II
PubDate: 2013-04-08T06:28:21Z
- Abstract: Available online 6 April 2013
- Rare sleeve fracture of the superior patella pole in an adult due to forceful passive physiotherapy following cast immobilization
- Abstract: Available online 6 April 2013
Publication year: 2013
Source:The Knee
Sleeve fractures are generally restricted to children or adolescents, and usually occur at the lower patella pole. Here we report on a superior pole sleeve fracture in an adult that occurred following forceful passive physiotherapy after cast immobilization. To our knowledge, this is the first report of a superior pole sleeve fracture in an otherwise healthy adult. The case highlighted that a diagnosis of a superior patella pole sleeve fracture in an adult can easily be missed because it is a rare injury, and hence is unlikely to be suspected by physicians.
PubDate: 2013-04-08T06:28:21Z
- Abstract: Available online 6 April 2013
- Changes in bone mineral density of the distal femur after total knee arthroplasty: A 7-year DEXA follow-up comparing results between obese and nonobese patients
- Abstract: Available online 6 April 2013
Publication year: 2013
Source:The Knee
Background and purpose Periprosthetic femoral bone mineral density (BMD, g/cm2) decreases after total knee arthroplasty (TKA) as a result of the stress-shielding phenomenon. It is not known whether obesity has an effect on this phenomenon or not. The aim of this study was to assess long-term periprosthetic BMD changes after TKA and compare whether there is a difference between obese and nonobese patients. Methods A total of 69 TKAs in 61 patients were performed, and BMD measurements of the distal femur were followed up to 7 years postoperatively. The patients were divided into two study groups according to their body mass index, and the groups were compared in relation to BMD and functional outcome. Results The mean of periprosthetic bone loss during the 7-year follow-up varied from 10.3% to 30.6% depending on the region of interest (p <0.0005). The highest bone-loss rates were detected during the first three postoperative months. A total of 26 patients were categorized as obese with a body mass index value of ≥30kg/m2. The obese patients' total periprosthetic BMD was higher at both baseline (8.6%) and 7 years after operation (p =0.05) (15.2%). Conclusion Periprosthetic bone loss around the femoral component continued for up to 7 years postoperatively. The loss of bone density was not associated with any negative clinical outcome in this study, but periprosthetic bone loss was of a smaller quantity in the obese which is probably due to higher weight induced stresses on bone.
PubDate: 2013-04-08T06:28:21Z
- Abstract: Available online 6 April 2013
- Infection rates in patients undergoing primary knee arthroplasty with pre-existing orthopaedic fixation-devices
- Abstract: Available online 27 March 2013
Publication year: 2013
Source:The Knee
Background Prior knee surgery in the setting of knee arthroplasty (KA) can influence the overall outcome of the procedure and render the operation more technically challenging. The effects of residual fixation devices on subsequent procedures about the knee are ill-defined. Some authors claim an increase in periprosthetic infection in this cohort of patients. The objective of this study was to evaluate the overall incidence of periprosthetic infections in patients undergoing primary KA with pre-existing osteosynthetic hardware in situ. Methods The current investigators retrospectively reviewed 124 patients undergoing knee arthroplasty and removal of orthopaedic fixation devices, due to prior high tibial osteotomies, fracture fixation or cruciate ligament reconstruction. The exclusion criterion was a prior history of infection of the fixation device. The mean follow-up time was 5.4years (range 15months to 9years). Nine patients were lost to follow-up. Results Joint aspiration was performed two weeks prior to surgery in 53 patients (42.4%) and intra-operative samples were obtained in 106 patients (84.8%), which did not show any bacterial growth. A subacute periprosthetic infection occurred after seven months in only one patient. Conclusion The results of the current study demonstrate that previously implanted osteosynthetic fixation devices do not significantly increase the risk of developing periprosthetic knee infections. A two-stage procedure with implant retrieval prior to total knee arthroplasty is not clinically indicated in the cohort described, amongst whom an infection rate of 0.9% was revealed.
PubDate: 2013-03-27T09:17:19Z
- Abstract: Available online 27 March 2013
- Factors influencing regional variability in the rate of total knee arthroplasty
- Abstract: Available online 23 March 2013
Publication year: 2013
Source:The Knee
Background and purpose Geographic variations in knee arthroplasty have been detected through international surveys. We aim to investigate in this study the influence of aging index, health budget, and number of orthopedic surgeons in the regional variations of the primary and revision TKA rate in a single European country, Spain. Material and methods Inpatient database of knee arthroplasty procedures for years 1997 to 2010 was obtained from the Spanish Ministry of Health, including 393,714 primaries and 37,037 revisions, segregated for each of the 17 regional health services in Spain. Crude and adjusted rates (direct method with total Spanish population per year) were calculated and used as dependent variables. Aging index, regional health budget, and number of orthopedic surgeons per region were used as independent variables in a Kruskal–Wallis test and a negative binomial regression analysis model. Results and conclusions With a mean crude rate for Spain of 76 primary TKA and 7 revision surgeries per 105 population and year, the mean adjusted rate per region oscillated between 702 and 27 primary TKA and 87 and 3 revisions per 105. A model was adjusted confirming the influence of aging index, health budget, and number of surgeons, but regional variations remained partly unexplained by these factors.
PubDate: 2013-03-27T09:17:19Z
- Abstract: Available online 23 March 2013
- TNF-α induced down-regulation of lysyl oxidase family in anterior cruciate ligament and medial collateral ligament fibroblasts
- Abstract: Available online 11 March 2013
Publication year: 2013
Source:The Knee
Background The lysyl oxidase (LOX) family has the capacity to catalyze the cross-linking of collagen and elastin, implicating its important fundamental role in injury healing. Tumor necrosis factor alpha (TNF-α) is considered to be an important chemical mediator in the acute inflammatory phase of the ligament injury. The role of the lysyl oxidase family induced by TNF-α in the knee ligaments' wound healing process is poorly understood. Our purpose was to determine the different expressions of the LOXs in poorly self-healing anterior cruciate ligament (ACL) and well functionally self-healing medial collateral ligament (MCL) induced by TNF-α. Methods Semi-quantitative PCR, quantitative real-time PCR and western blot were performed for original research. Results The results showed that all LOX family members were expressed at higher levels in MCL than those in ACL fibroblasts; the significant differences existed in the down-regulations of the LOXs induced by TNF-α; and the TNF-α-mediated down-regulations of the LOXs were more prominent in ACL than those in MCL fibroblasts. 1–20ng/ml TNF-α down-regulated mRNA levels in ACL and MCL fibroblasts by up to 76% and 58% in LOX; 90% and 45% in LOXL-1; 97.5% and 90% in LOXL-2; 89% and 68% in LOXL-3; 52% and 25% in LOXL-4, respectively. Protein assay also showed LOXs had lower expressions in ACL than those in MCL. Conclusions Based on these results, the differential expressions of the LOXs might help to explain the intrinsic differences between the poorly self-healing ACL and well functionally self-healing MCL. Clinical relevance .
PubDate: 2013-03-12T07:28:09Z
- Abstract: Available online 11 March 2013
- Survival and clinical outcome of isolated high tibial osteotomy and combined biological knee reconstruction
- Abstract: Available online 8 March 2013
Publication year: 2013
Source:The Knee
Purpose We sought to determine survival and clinical outcomes of high tibial osteotomy (HTO) with or without articular cartilage surgery and/or meniscal allograft transplantation in patients with medial compartment chondral pathology, varus malalignment, and/or meniscal deficiency, whether there is any difference in survival or clinical outcome between these patient cohorts, and whether there is any difference between opening- (OWHTO) and closing-wedge (CWHTO) techniques. Methods A systematic review of multiple medical databases was performed using PRISMA guidelines. Study quality was assessed via modified Coleman Methodology Scores (MCMS). Results Sixty-nine studies were included (4557 subjects). MCMS rating was overall poor. Mean follow-up was 7.1years. Mean subject age was 53years. Survival of isolated HTO was 92.4%, 84.5%, 77.3%, and 72.3% at 5, 10, 15, and 20 years of follow-up. At 5years of follow-up, HTO with articular cartilage surgery had significantly greater survival (97.7%) than either isolated HTO (92.4%) or HTO with MAT (90.9%). Isolated HTO, HTO with articular cartilage surgery, and HTO with MAT all significantly improved subjective and objective clinical outcome scores. At two years of follow-up, survival was significantly greater following OWHTO (98.7%) versus CWHTO (96.7%). However, at all other time points with or without combined articular cartilage surgery and/or MAT, there was no significant survival difference between the techniques. Conclusions Survival and clinical outcomes of isolated HTO were excellent at short- and mid-term follow-ups, but deteriorated with time. HTO with concomitant procedures also demonstrated excellent early survival and clinical outcomes that deteriorated with time (up to 10years).
PubDate: 2013-03-12T07:28:09Z
- Abstract: Available online 8 March 2013
