Background Rotational malalignment of total knee arthroplasty (TKA) has been correlated with patellofemoral maltracking, knee instability, and stiffness. CT is the most accurate method to assess rotational alignment of prosthetic components after TKA, but inter-and intraobserver reliability of CT scans for this use has not been well documented. Questions/purposes The objective of this study was to determine the inter-and intraobserver reliability and the repeatability of the measurement of TKA component rotation using two-dimensional CT scans. Methods Fifty-two CT scans of TKAs being evaluated for revision surgery were measured by three different physicians. An orthopaedic resident and attending measured the same scans twice (more than 2 weeks apart) and a musculoskeletal radiologist measured them once. To assess interobserver reliability, intraclass correlation coefficients (ICCs) with two-way mixed-effects analysis of variance models as well as 95% confidence intervals for each were done. The repeatability coefficient was calculated as well, which is defined as the difference in measurements that include 95% of the values. This indicates the magnitude of variability among measurements in the same scale, which in this study is degrees. Results The interobserver ICC measurement for the femoral component was 0.386 (poor), and it was 0.670 (good) for the tibial component. The interobserver ICC for the combined rotation measurements was 0.617 (good). The intraobserver ICC for the femoral component was 0.606 (good), and it was 0.809 (very good) for the tibial component. The intraobserver ICC for combined rotation was 0.751 (good). The intraobserver repeatability coefficient for the femoral component was 0.49°, 10.64°for the tibial component, and 12.29°for combined rotation. Conclusions In this study, the inter-and intraobserver reliability, and the repeatability, of TKA component rotation were variable. This raises concern about whether CT scan is diagnostic in the assessment of component malrotation after TKA.

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Background Higher postoperative quadriceps function has been positively associated with surgical outcomes after anterior cruciate ligament reconstruction (ACLR). However, the impact of autograft harvest and/or a concomitant meniscal procedure on the recovery of quadriceps strength is not well defined. Purpose To describe postoperative recovery of quadriceps strength following ACLR related to autograft selection, meniscal status, and sex. Study Design Retrospective Cohort. Methods One hundred and twenty-five participants who underwent ACLR with either a hamstring tendon (HT), bone-patellar tendon-bone (BPTB) or quadriceps tendon (QT) autograft were included. At postoperative months 3, 6 and 9, each participant completed an isometric quadriceps strength testing protocol at 90-degrees of knee flexion. Participants’ quadriceps average peak torque (Q-AvgPKT), average peak torque relative to body weight (Q-RPKT), and calculated limb symmetry index (Q-LSI) were collected and used for data analysis. Patients were placed in groups based on sex, graft type, and whether they had a concomitant meniscal procedure at the time of ACLR. At each time point, One-way ANOVAs, independent samples t-test and chi-square analyses were used to test for any between-group differences in strength outcomes. Results At three months after ACLR, Q-RPKT was significantly higher in those with the HT compared to the QT. At all time points, males had significantly greater Q-RPKT than females and HT Q-LSI was significantly higher than BPTB and QT. A concomitant meniscal procedure at the time of ACLR did not significantly affect Q-LSI or Q-RPKT at any testing point. Conclusion This study provides outcomes that are procedure specific as well as highlights the objective progression of quadriceps strength after ACLR. This information may help better-define the normal recovery of function, as well as guide rehabilitation strategies after ACLR. Level of Evidence 3