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High-Grade Percutaneous Medial Collateral Ligament Pie-Crusting Is Not Associated With Clinically Meaningful Valgus
Tanner Nishioka1, Napatpong Thamrongskulsiri2, Felipe Casanova1
1Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA.
Background:
Medial collateral ligament (MCL) pie-crusting is used during medial meniscal surgery to improve visualization and reduce the risk of chondral injuries. However, some surgeons extend the release site beyond routine incremental perforation, and the effect of this more extensive release on postoperative medial laxity remains unclear.
Purpose:
To determine whether high-grade percutaneous MCL pie-crusting during medial meniscus posterior root tear (MMPRT) repair results in clinically meaningful valgus instability postoperatively as assessed by valgus stress radiography.
Study Design:
Case series; Level of evidence, 4.
Methods:
A retrospective review was performed of patients who underwent isolated MMPRT repair with high-grade MCL pie-crusting and no prior knee ligament surgery. High-grade pie-crusting was defined intraoperatively by an audible and palpable release and a substantial medial compartment opening (≥6 mm) under arthroscopic visualization. Postoperative bilateral valgus stress radiographs were obtained at a mean of 5.9 ± 2.0 months with the knee positioned at 20° of flexion. Gapping was measured in millimeters, and the side-to-side difference was calculated using the contralateral knee as an internal control. An a priori power analysis based on a 3.2-mm threshold for clinically meaningful medial-sided laxity demonstrated a required sample size of 15 patients. The side-to-side difference in medial compartment gapping was analyzed using the 1-sample t test compared with the 3.2-mm threshold.
Results:
A total of 21 patients met inclusion criteria. The mean medial compartment gapping was 7.84 ± 1.65 mm in the operative knee and 6.62 ± 1.37 mm in the contralateral knee. The mean side-to-side difference was 1.21 ± 1.07 mm (95% CI, 0.73-1.70 mm). The observed difference was significantly less than the 3.2-mm threshold associated with clinically meaningful medial-sided instability (P < .001).
Conclusion:
High-grade percutaneous MCL pie-crusting advanced to a defined intraoperative endpoint during MMPRT repair resulted in small increases in medial compartment gapping that remained below biomechanically defined instability thresholds. These preliminary findings suggest that high-grade MCL pie-crusting improves visualization and instrumentation without being associated with clinically meaningful valgus laxity postoperatively.
