Anterior Cruciate Ligament Injuries With Segond Fractures Are Associated With Lateral Meniscus Oblique Radial Tears and Residual Rotational Instability but Not Anatomic Internal Tibial Rotation, Compared With Those Without Segond Fractures.

PURPOSE: To investigate whether anterior cruciate ligament (ACL)-injured knees with Segond fractures are associated with anatomic tibial rotation, increased lateral meniscus tears, and residual rotational instability. METHODS: This retrospective cohort study included patients who underwent primary ACL reconstruction (double-bundle hamstrings or rectangular bone-patellar tendon-bone graft) between 2015 and 2023, with ≥2 years of follow-up and second-look arthroscopy. Patients with other ligament injuries (excluding grade 1-2 medial collateral ligament injuries), non-Segond fractures, previous knee surgery, open physes, or advanced osteoarthritis were excluded. Based on preoperative radiographs, patients were classified into Segond-positive (S+) and -negative (S-) groups. Outcome measures included pivot-shift test, stress radiographic anterior instability, tibiofemoral rotation angle on magnetic resonance imaging, Lysholm, Tegner, and International Knee Documentation Committee scores measured preoperatively and at 2 years postoperatively. Meniscal tear patterns, treatment, and healing status at second-look arthroscopy were recorded. RESULTS: We analyzed 1011 knees comprising 47 S+ knees (4.6%). The S+ group showed significantly smaller tibiofemoral rotation angle values (-1.7° ± 2.5° vs 8.9° ± 7.7°), higher rates of lateral meniscal injury (91.5% vs 36.9%), and lateral meniscus oblique radial tears (78.7% vs 4.6%) than the S- group (all P < .001). The S+ group had a significantly higher postoperative pivot-shift test (50.0% vs 6.1%, P < .001). Both groups had similar revision rates and meniscal healing. Patient-reported outcomes improved significantly in both groups, with no intergroup differences. Overall, 64.1% and 81.6% of patients achieved the minimal clinically important difference for the Lysholm and International Knee Documentation Committee scores, respectively. Segond fracture was independently associated with a positive pivot-shift test at 2 years postoperatively (odds ratio, 13.579; 95% confidence interval, 6.824-26.970; P < .001). CONCLUSIONS: Compared with ACL injuries without Segond fractures, ACL injuries associated with Segond fractures were associated with external tibial rotation, increased lateral meniscus oblique radial tears, and greater residual rotational instability 2 years postoperatively. LEVEL OF EVIDENCE: Level III, retrospective cohort study.