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Updated: Sep 21, 2025
Author Spotlight: Double Posteromedial Approach for Treating Posterior Cruciate Ligament Cysts
Published on: October 20, 2023
Posteromedial vertical capsulotomy selectively expands the intraoperative extension gap in cruciate-retaining total
Kensuke Yoshino1,2, Ryutaku Kaneyama3,4, Hitoshi Watanabe5
1Department of Orthopaedic Surgery, Chiba Aoba Municipal Hospital, 1273-2 Aobacho, Chuo-ku, Chiba, 260-0852, Japan. knskysn@gmail.com.
Purpose:
Effective soft-tissue balancing procedures for expanding the extension gap (EG) are needed in cases of gap mismatch in total knee arthroplasty (TKA). A posteromedial vertical capsulotomy (PMVC) is performed to restore mobility in a knee with a flexion contracture. The purpose of this study was to evaluate the effectiveness and safety of PMVC for intraoperative gap adjustment in cruciate-retaining TKA.
Methods:
A total of 120 consecutive knees undergoing cruciate-retaining TKA for varus osteoarthritis were examined. The EG and flexion gap (FG) with a trial femoral component were measured using spacer blocks before and after PMVC. PMVC was performed when the first FG was larger than the first EG by > 2 mm.
Results:
Sixty-five knees underwent PMVC, and the mean EG significantly increased by 2.4 mm (p < 0.001). This increase was significantly larger than that of the FG by 2.0 mm (p < 0.001). The preoperative extension range of motion (ROM) was negatively correlated with the EG change after PMVC (r = - 0.39, p = 0.001). A receiver operating characteristic (ROC) curve indicated a preoperative extension ROM cut-off of -10° for predicting PMVC (sensitivity 72.3%, specificity 56.4%). No associated complications were observed during a minimum 2-year follow-up period, and there was no difference in the postoperative Knee Society Score between the PMVC and non-PMVC groups.
Conclusion:
PMVC may be a useful soft-tissue treatment for gap adjustment with a selective EG expansion in TKA, especially in cases of a limited preoperative extension of - 10° or less.
Level Of Evidence:
Therapeutic study, level III.
