Summary

This novel PMCR technique with a single femoral tunnel plus an adjustable-loop fixation system showed to be safe and effective in restoring medial stability

Abstract

Objectives
Several posteromedial corner reconstructions (PMCR) techniques have been described, most of them using 2 femoral tunnels and interference screw fixations. The aim of this study is to report a novel PMCR technique using a single graft and unique femoral tunnel plus an adjustable-loop suspensory fixation.

Methods

Prospective cohort of consecutive patients with high-grade PMC injuries treated with this novel technique by the same surgical team from 2021 to date. High-grade PMC injuries with residual medial laxity were confirmed by magnetic resonance imaging (MRI) and stress x-rays in all cases and had a minimum 6 months follow-up. Surgery was performed through mini open approaches and fluoroscopic guidance, using a single non-irradiated fresh frozen peroneus tendon allograft. A single femoral tunnel at the mid-point between the posterior oblique ligament (POL) and the superficial medial collateral ligament (MCLs) footprints was drilled. For the tibia, 2 independent 30mm tunnels for the POL and MCLs were drilled at the corresponding footprints. An adjustable-loop cortical button was used to fix the allograft loop to the femur, and bioabsorbable PEEK screws for the tibial ends of the graft. Postoperative rehabilitation protocol included immediate passive ROM excercises and weight-bearing as tolerated. At final follow up knee stability was assessed by physical examination according to IKDC, and comparative stress x-rays. Intraoperative complications (IOC): tunnel convergence, loss or failed fixation; and postoperative complications (POC): residual instability, deep or superficial infection, wound complications or arthrofibrosis where registered.

Results

Sample included 18 patients (14 males) with an average of 49 years of age [25-70]. Most injuries resulted from high-energy mechanisms (12). Surgery was performed in an average of 14 weeks following injury [3-30]. Only 5 PMCR where isolated and 13 where in the setting of a multiligament knee reconstruction (4 PMC + ACL, 1 PMC + PCL, 5 Schenck IIIM and 3 Schenck IV). At final follow up, the median ROM was 0° [0-3] – 119° [100-135] and knee stability was IKDC A (16) or B (2) at 0° and A (8) or B (10) at 20°. The stress X-rays showed a difference of 1.2 mm [0-2] at 0° and 1.6 mm [0-3] at 20° versus the uninjured knee. No patients had a pathological residual laxity that required brace or revision surgery, and no IOC or POC where registered.

Conclusions

This novel PMCR technique with a single femoral tunnel plus an adjustable-loop fixation system showed to be safe and effective in restoring medial stability. This technique offers the advantage of femoral bone stock preservation, avoiding tunnel convergence, and a suspensory fixation that aids in a graft tensioning and prevents the possible loss of pull-out strength and slippage associated with interference screw fixation in the femur.