1Vander Molen J, 1Dugan S, 2Singleton M, 2Ehrlich D
1Chicago College of Osteopathic Medicine, Midwestern University, Oakbrook Terrace, IL, United States; 2College of Graduate Studies, Midwestern University, Downers Grove, Illinois, United States
Introduction: The anterolateral ligament (ALL) of the knee is a fibrous band that limits internal tibial rotation. The ALL may be torn in conjunction with the anterior cruciate ligament (ACL). ACL-deficient knees often exhibit rotational instability after operative interventions that fail to address the ALL. Although the ALL has been previously characterized, there is limited information on sex-based differences in ALL anatomy. It is known that sex-based differences exist in ACL characteristics such as cross-sectional area. If similar differences exist in the ALL, these differences may have implications for ALL reconstruction in ACL-deficient knees. The goal of this study was to determine if there are sex-based structural differences in the ALL.
Methods: The study sample included 23 anatomical donor bodies; 33 total native cadaveric knees were dissected. Digital calipers were used to record ALL measurements including thickness, length, width at joint line, and origin location relative to femoral and tibial landmarks. Qualitative descriptors of ALL origin and insertion were also recorded and categorized. One dissection per cadaver was randomly selected for statistical analyses. Measurements were size-corrected using femoral transepicondylar width, and sex differences were evaluated using Student’s T-test. Analysis of Variance (ANOVA) was performed to assess relationships between origin categories and quantitative measures.
Results: The ALL was found to be present in 31 of 33 knee dissections. Transepicondylar width was significantly larger in males (p = 0.0004). No other sex differences in ALL dimensions were significant. Four ALL origin categories were identified: 1) Posteroproximal to LCL origin; 2) Anterodistal to LCL origin; 3) Posterodistal to LCL origin; and 4) Anteroproximal to LCL origin. Comparisons between origin categories and quantitative variables showed that knees with an anterodistal ALL origin had thicker ALLs compared to knees with a posterodistal origin (p = 0.043). There was a definite meniscal attachment between the ALL and the lateral meniscus in all specimens analyzed.
Conclusion: The ALL was identified in 94% of dissections. No significant sex differences were found in dimensions or location of the ALL. Of the 4 ALL origin categories, the anterodistal origin was associated with increased ALL thickness compared to the posterodistal. Absence of sex differences in ALL morphology suggests sex is not a deciding factor when considering performing ALL repair. However, ALL thickness was found to vary by origin site, suggesting that origin location may be an indicator for performing concomitant ALL repair in ACL-deficient knees.
