The association between high-grade pivot-shift and complete lateral meniscus posterior root tear after anterior cruciate ligament ruptures

Abstract

Objective To investigate the association between high-grade pivot-shift and complete lateral meniscus posterior root (LMPR) tear in patients with anterior cruciate ligament (ACL) ruptures. Methods From January 2013 to December 2017, a total of 86 ACL injured patients with LMPR tears were reviewed retrospectively. There were 66 males and 20 females with an average age of 27.8±8.3 years (range 16-49 years) and an mean BMI of 25.1±3.2 kg/m2 (range 17.4-33.9 kg/m2). The average duration from injury to surgery was 33.5±79.4 weeks (range 3 days to 11 years). All patients were classified into high-grade pivot-shift group (60 patients of IKDC grade II-III) and low-grade pivot-shift group (26 patients of IKDC grade 0-I) according to the results of pivot-shift tests under anesthesia before ACL reconstructions. Predictive factors of high-grade pivot-shift were analyzed by multivariable Logistic regression, involving degree of LMPR tear, integrity of meniscofemoral ligament, width of lateral meniscal extrusion, KT-1000 arthrometer side-to-side difference, age, sex, and BMI. Results The prevalence of complete LMPR tear in high-grade pivot-shift group was higher than that in low-grade pivot-shift group. High-grade pivot-shift was associated to complete LMPR tear [OR=4.096, 95% CI(1.339, 12.371), P=0.013] and KT-1000 arthrometer side-to-side difference [OR=9.632, 95% CI (3.095, 29.975), P 0.05). Conclusion In patients with ACL ruptures, complete LMPR tear was an independent risk factor of high-grade pivot-shift, especially for patients with 12 weeks at least duration from injury to surgery. Key words: Anterior cruciate ligament; Menisci, tibial; Joint instability; Risk factors; Case-control studies