Efficacy of posterior capsular release for flexion contracture in posterior-stabilized total knee arthroplasty

Abstract

Purpose Posterior capsular contracture causes stiffness during knee extension in knee osteoarthritis. Furthermore, in posterior-stabilized total knee arthroplasty (PS-TKA), a unique design such as the cam mechanism could conflict with the posterior capsule (PC) causing flexion contracture (FC). However, few studies have focused on the anatomical aspects of the PC. This study aimed to investigate the anatomical site and forms of posterior capsular attachment to the femoral cortex, and to evaluate the efficacy of posterior capsular release for FC by assessing changes in knee extension angles using a navigation system. Methods Attachment sites of the PC were investigated in 10 cadaveric knees using computed tomography. PS-TKA was performed in six cadaveric knees using a navigation system to evaluate the efficacy of posterior capsular release for FC. Posterior capsular release was performed stepwise at each part of the femoral condyle. Results The gastrocnemius tendon and PC were integrally attached to the femoral cortex at the medial and lateral condyles, whereas the PC at the intercondylar fossa was independently attached directly to the femoral cortex. Moreover, the PC at the intercondylar fossa was attached most distally among each femoral condyle. Posterior capsular release at the intercondylar fossa allowed 11.4° ± 2.8° improvement in knee extension. This angle was further improved by 5.5° ± 1.3°, after subsequent capsular release at the medial and lateral condyles. Conclusion The forms and sites of posterior capsular attachment differed based on the part of the femoral condyle. Stepwise posterior capsular release was effective for FC in PS-TKA. Level of evidence III.

Additional Distal Femoral Resection Minimally Improves Terminal Knee Extension: A Systematic Review and Meta-Regression Challenging the Dogma

“…Kinoshita et al. [ 14 ] performed a cadaveric study identifying attachment sites of the posterior capsule using computed tomography scan. They performed a stepwise release and found the gastrocnemius tendon and posterior capsule were integrally attached to the femoral cortex at the medial and lateral condyles, whereas the posterior capsule at the intercondylar fossa was independently attached directly to the femoral cortex.…”

“…Several surgical methods to correct preoperative flexion contracture have been described including intraoperative manipulation, removal of posterior condylar osteophytes and loose bodies, posterior capsular release, posterior cruciate ligament release, decrease of posterior condylar offset, and additional resection of the distal femur [ [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] ]. No consensus has emerged on the optimal technique to restore full extension [ 22 ].…”

Limited medial posterior capsular release increases the intraoperative medial component gap while maintaining the joint varus angle at extension in posterior‐stabilized total knee arthroplasty

“…The effects of posterior capsular release on component gaps at 0° and 90° have been analysed in cadaveric knees [2]. In a cadaveric study, Kinoshita et al demonstrated that there are measurable effect differences in knee extension angles when the posterior capsule is released at each of three parts of the distal femur in a stepwise manner starting with release at the intercondylar notch followed by medial and then lateral release [7]. In line with previous reports, our study found that posterior capsular release from the medial side to and including the intercondylar notch increased the component gap sufficiently at extension without component gap change at mid to deep flexion in TKA.…”

“…Mid‐flexion instability leads to increased polyethylene wear and causes a subjective feeling of instability when walking on sloped surfaces or when descending stairs [3, 5, 9]. Posterior capsular release across the full medio‐lateral width of the distal femur (hereafter referred to as full PCR) has been found to increase the component gap at extension without an increase in the component gap at flexion and provided successful outcomes on controlling gap mismatch [2, 7]. However, this procedure theoretically carries an inherent risk of injury to the important neurovascular structures contained in the popliteal fossa [20].…”

Pleiotropic Long-Term Effects of Atorvastatin on Posttraumatic Joint Contracture in a Rat Model

“…Knees and elbows have been shown to be the most vulnerable joints to PJTS. A flexion contracture model was chosen to mimic PJTS in the knee, the most debilitating and clinically relevant form [ 17 , 28 ]. In particular, in a flexion contracture, the posterior capsule has proven to be at the heart of this condition with its densely packed connective tissue, whereas its anterior counterpart remains largely unaffected [ 29 , 30 ].…”