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

Abstract 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.