Single-strand superficial medial collateral ligament reconstruction with a peroneus longus split graft provides reliable control of anteromedial rotatory instability combined with anterior cruciate ligament reconstruction: A 2-year clinical cohort study.

PURPOSE: To evaluate 2-year clinical, radiological, and patient-reported outcomes after combined anterior cruciate ligament (ACL) reconstruction and single-strand superficial medial collateral ligament (sMCL) reconstruction using a peroneus longus split graft (PLSG) in patients with anteromedial rotatory instability (AMRI).

METHODS: Patients with ACL insufficiency and clinically and intraoperatively confirmed AMRI who underwent combined ACL and sMCL reconstruction using a PLSG were retrospectively identified and prospectively followed. AMRI was diagnosed in this study based on a combination of ACL insufficiency, increased anteromedial drawer in external tibial rotation, medial laxity on valgus stress testing at 20° of knee flexion, pivot-shift grading as an indicator of overall rotatory instability of the knee, and supportive arthroscopic findings such as the medial meniscus squeeze sign. At a minimum follow-up of 2 years, 59 of 63 patients (mean age 30 years, 48% female) were available for evaluation. Postoperative stability was assessed using KT-1000 instrumented side-to-side measurements for the Lachman test and anterior drawer test at 90° flexion with neutral and 15° external tibial rotation (AMRI-related). Pivot-shift grading and valgus stress radiographs obtained at 20° of knee flexion were additionally performed. Patient-reported outcome measures (PROMs) included International Knee Documentation Committee (IKDC) Subjective, Lysholm, Tegner activity scale, and return-to-any-sport rate. A non-inferiority margin of 3 mm for side-to-side differences was predefined.

RESULTS: The mean side-to-side difference for the AMRI-related anterior drawer was 0.0 ± 1.3 mm (95% CI: -0.4 to 0.3 mm), meeting the predefined non-inferiority criterion (upper one-sided 95% confidence limit 0.3 mm; p < 0.001). The mean Lachman side-to-side difference was 1.8 mm ± 1.3 mm and remained within clinically acceptable limits. A negative pivot-shift was observed in 93% of patients. IKDC (59 ± 20 to 85 ± 12; p < 0.001) and Lysholm (61 ± 25 to 89 ± 11; p < 0.001) scores improved significantly, whereas the Tegner Activity Scale (5.8 ± 1.7 to 5.2 ± 1.6; p = 0.007) showed a small but significant decrease. The mean side-to-side difference in medial joint opening on valgus stress radiographs was 0.6 mm ± 1.0 mm, remaining below the predefined clinical reference threshold. At 2 years, 66% of patients had returned to any sports.

CONCLUSION: Combined ACL and single-strand sMCL reconstruction using a PLSG was associated with low postoperative side-to-side differences, satisfactory postoperative stability, favourable postoperative PROMs and low ankle donor-site morbidity at 2-year follow-up. This tunnel-sparing technique may be considered a reasonable surgical option for patients with ACL insufficiency and clinically relevant concomitant AMRI.

LEVEL OF EVIDENCE: Level IV.