Anterior cruciate ligament (ACL) reconstructions with quadriceps tendon (QT) grafts are gaining popularity, both in primary and revision procedures. Recently, the role of the anterolateral ligament (ALL) of the knee in improving rotational knee stabi...

Background and Objectives: It is unknown whether the tibial tuberosity–tibial intercondylar midpoint (TT–TIM) distance can be interchangeably measured on axial computed tomography (CT) and magnetic resonance imaging (MRI). The objective of this retrospective cross-sectional comparative study was to evaluate the intermethod agreement of the TT–TIM distance on axial CT and MRI and its bias towards tibial rotation (TR), age, sex, and body side. Materials and Methods: On axial CT and MRI of 15 consecutive knee pairs where each pair belonged to the same patient with no pathology affecting the tibial circumference and tibial tuberosity, TT–TIM distance and TR were measured by two blinded radiologists at 2-week intervals. Upon checking the symmetry of distributions (Shapiro–Wilk test), differences between matched knee pairs (Wilcoxon signed-rank test), intermethod (Bland–Altman plot) and interrater agreement (intraclass correlation coefficient [ICC]), and correlations (Spearman rank correlation) were assessed. Results: The mean intermethod difference in TT–TIM distance was not statistically significant (−0.4 mm [−1.82, 0.96]; p = 0.52). The TT–TIM distance did not differ between knee pairs (p = 0.68), its interrater agreement was almost perfect (ICC > 0.81), and no bias towards TR (p > 0.66), age (p > 0.14), sex (p = 0.66), and body side (p > 0.37) was found. Conclusions: The TT–TIM distance can be interchangeably measured on axial CT and MRI with almost perfect interrater agreement, unbiased towards TR, age, sex, and body side.

Background/Objectives: To compare the morphological and biomechanical properties of a quadrupled gracilis (4GR) graft with two standard hamstring grafts for anterior cruciate ligament (ACL) reconstruction: a quadrupled semitendinosus (4ST) graft and a doubled semitendinosus–gracilis (2ST2GR) graft. Methods: Tendon specimens were obtained from 30 cadaveric donors (mean age, 42.6 years; range, 21–56 years). Tendon and graft dimensions were measured before biomechanical testing. Grafts underwent standardized preconditioning followed by load-to-failure testing at a displacement rate of 20 mm/min. Differences between graft types were analyzed using a generalized linear mixed-effects model, with results expressed as estimated marginal means with 95% confidence intervals (CI). Results: The mean 4GR graft length was 64.7 (95% CI, 61.6–67.8) mm, with 80% exceeding 60 mm. Graft diameter was greatest in the 4ST group, intermediate in the 2ST2GR group, and smallest in the 4GR group (7.98 [95% CI, 7.67–8.29], 7.41 [95% CI, 7.12–7.70], and 6.12 [95% CI, 5.89–6.36] mm, respectively). The 4ST graft demonstrated significantly greater maximum force than both the 4GR and 2ST2GR grafts, whereas no significant difference was observed between the 4GR and 2ST2GR grafts. In contrast, tensile strength was significantly higher in the 4GR grafts than in both the 4ST and 2ST2GR grafts. Stiffness was significantly higher in the 4ST grafts than in the 4GR grafts, whereas Young’s modulus was significantly higher in the 4GR grafts than in the 4ST grafts. Conclusions: The 4GR graft provided sufficient length for all-inside ACL reconstruction in most specimens. Despite its smaller diameter and lower absolute load-bearing capacity than 4ST, the 4GR graft demonstrated higher tensile strength and Young’s modulus, indicating favorable intrinsic mechanical properties. These findings may help inform graft selection in selected reconstructive procedures.

Background and Objectives: To validate a computed tomography (CT) measure of tendon yaw (TY) and determine its diagnostic specificity, precision, and clinical relevance in recurrent patellar instability (RPI) in comparison with standard imaging tests (SIT1, SIT2), femoral trochlear dysplasia (FTD), and vastus medialis obliquus (VMO) morphology. Materials and Methods: This retrospective cross-sectional study included 113 subjects (187 knees) examined using a standardized CT protocol for RPI following strict exclusion criteria. TY, SIT1, and SIT2 were measured using predefined axial landmarks. VMO cross-sectional area was assessed at three standardized levels. Diagnostic performance, measurement precision, and interrater agreement were evaluated. Results: TY significantly distinguished recurrent dislocators from nondislocators (p = 0.003) and was independent of age, sex, laterality, and femoral, tibial, or knee rotation (p ≥ 0.42). A threshold of ≥22° demonstrated high diagnostic specificity (92%; 95% CI, 85–97%), with a normal cutoff defined as ≤12°. Measurement precision was approximately 90%. SIT1 and SIT2 were influenced by femoral and knee rotation but not tibial rotation. All imaging tests were associated with FTD (p < 0.0001). No significant correlation was found between any imaging test and VMO area, although VMO was reduced in recurrent dislocators and in women. Conclusions: TY is a direct and highly specific CT measure of extensor mechanism yaw (z-axis rotation) that avoids indirect osseous and soft-tissue surrogates, supporting confirmatory diagnostic assessment and preoperative planning in RPI.