- Design
- Retrospective case series, level of evidence 4
- Population
- 21 patients with isolated medial meniscus posterior root repair and high-grade MCL pie-crusting
- Primary outcome
- Side-to-side medial gapping on valgus stress radiographs at about 6 months
- Effect
- Mean difference 1.21 mm (95% CI 0.73 to 1.70) vs 3.2 mm laxity threshold; P < 0.001
This retrospective case series looked at 21 patients who had isolated medial meniscus posterior root repair with high-grade percutaneous pie-crusting of the medial collateral ligament. High grade meant an audible and palpable release with at least 6 mm of medial opening on arthroscopy. Valgus stress radiographs were taken about six months later, and the contralateral knee served as control.
Medial gapping averaged 7.84 mm in the operated knee and 6.62 mm in the other knee. The mean side-to-side difference was 1.21 mm (95% CI 0.73 to 1.70), below the 3.2 mm threshold used for clinically meaningful laxity (P < 0.001).
This is level 4 evidence from a small series with no comparison group. It argues that the release does not obviously cause laxity at six months, but not that it is risk-free, and not that it improves repair outcomes.
- Pie-crusting to gain medial access did not produce laxity above 3.2 mm at about six months in this series.
- Release stepwise and stop at the needed opening rather than aiming for a number.
- Obtain stress radiographs if there is clinical doubt about medial stability.
- Counsel patients that follow-up was short and numbers were small.
Why it matters
Surgeons may avoid the release for fear of instability, risking cartilage damage from poor access.
Don't overread it
Twenty-one patients at six months with no control group cannot show that extensive release is safe in the long term.
The statistics, in plain English
The mean difference of 1.21 mm with an interval of 0.73 to 1.70 mm sits well below the 3.2 mm threshold, so laxity above that line is unlikely on average. Averages can hide individuals above the line, and there was no comparison with patients who had no release.
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