Purpose Patellar component positioning and patellofemoral kinematics are of great importance in total knee arthroplasty (TKA). The factors inluencing patellar tilt are femoral rotation and lateral patellar release. However, the efect of patellar component size remains unknown. The aim of this study was to evaluate the intra-operative risk factors for patellar tilt, particularly the efect of the patellar component size. The hypothesis was that increasing the patellar component size would reduce the risk of patellar tilt. Methods 878 primary TKAs with patellar resurfacing were included between January 2015 and October 2018. Analysis was performed at 1-year postoperatively on patients categorized into two groups: patellar tilt (PT) and no patellar tilt (NPT). A multivariate analysis was performed for the efect of patellar component size, femoral rotation, femoral overbuilding, patellar thickness and lateral release on patellar tilt risk. Secondary analysis was performed for any diference in clinical outcomes and revision rates between groups. Results Multivariate analysis showed that increasing the patellar component size decreased the risk of patellar tilt by 37% (p < 0.001). Placing the femoral component at 3° of external rotation decreased the risk of patellar tilt by 67% (p < 0.001). Secondary analysis showed better clinical outcomes in the NPT group, especially regarding global satisfaction, and KSS objective and subjective scores. The revision for any cause was less in the NPT group (p = 0.019). The cause for TKA revision was related to the patellar in 11% of cases in the NPT group and 65% in the PT group (p < 0.001). Conclusion Increased patellar component size and positioning the femoral component in external rotation decreases the risk of patellar tilt, improves clinical outcomes and decreases the rate of surgical revision. Level of evidence III.

Purpose To determine whether isokinetic muscle recovery following ACLR using a hamstring tendon (HT) would be equivalent (non-inferior) in knees that had high-grade pivot-shift and adjuvant modified Lemaire procedure versus knees that had minimal pivot-shift and no adjuvant modified Lemaire procedure. Methods We evaluated 96 consecutive patients that underwent primary ACLR. Nine were excluded because of contralateral knee injury, and of the remaining 87, ACLR was performed stand-alone in 52 (Reference group), and with a Lemaire procedure in 35 (Lemaire group) who had high-grade pivot-shift, age < 18, or genu recurvatum > 20°. At 6 months, isokinetic tests were performed at 240°/s and 90°/s to calculate strength deficits of hamstrings (H) and quadriceps (Q). At 8 months, patients were evaluated using IKDC, Lysholm, and Tegner scores. Results Compared to the Reference group, the Lemaire group were younger (23.0 ± 2.5 vs 34.2 ± 10.5, p = 0.021) with a greater proportion of males (80% vs 56%, p < 0.001). The Lemaire group had no complications, but the Reference group had one graft failure and one cyclops syndrome. Strength deficits at 240°/s and at 90°/s were similar in both groups, but mixed H/Q ratios were lower for the Lemaire group (1.02 ± 0.19 vs 1.14 ± 0.24, p = 0.011). IKDC and Lysholm scores were similar in both groups, but Tegner scores were higher in the Lemaire group (median, 6.5 vs 6.0, p = 0.024). Conclusions ACLR with a modified Lemaire procedure for knees with rotational instability grants equivalent isokinetic muscle recovery as stand-alone ACLR in knees with no rotational instability. For ACL-deficient knees with high-grade pivot-shift, a Lemaire procedure restores rotational stability without compromising isokinetic muscle recovery. Study design Level III, comparative study.

Purpose: Meniscal lesions are commonly associated with anterior cruciate ligament (ACL) rupture. Meniscal repair, when possible, is widely accepted as the standard of care. Despite advancements in surgical and rehabilitation techniques, meniscal repair may impact muscle recovery when performed in conjunction with ACL reconstruction. The objective of this study was to explore if meniscal repairs in the context of ACL reconstruction affected muscle recovery compared to isolated ACL reconstruction. Methods: Fifty-nine patients with isolated ACL reconstruction were compared to 35 patients with ACL reconstruction with an associated meniscal repair. All ACL reconstructions were performed using hamstring grafts with screw-interference graft fixation. Isokinetic muscle testing was performed between six and eight months of follow-up. Muscle recovery between both groups was compared. A further subgroup analysis was performed to compare muscle recovery function of gender and meniscal tear location. Tegner scores were assessed at six months’ follow-up. Results: No significant differences were found between the two groups regarding muscle recovery. No difference in muscle recovery was found concerning gender. Lesion of both menisci significantly increased the deficit of hamstrings muscular strength at 60°/s compared to a lesion of one meniscus (26.7% ± 15.2 vs. 18.1% ± 13.5, p = 0.018) and in eccentric test (32.4% ± 26.2 vs. 18.1% ± 13.5, p = 0.040). No significant differences were found concerning the Tegner score. Conclusion: Meniscal repairs performed during an ACL reconstruction do not impact muscle recovery at 6–8 months post-operatively compared to an isolated ACL reconstruction. However, reparations of both menisci appear to impact hamstring muscle recovery negatively. Level of evidence: III, Retrospective cohort study