RESUMEN
BACKGROUND: Anterior cruciate ligament (ACL)-deficient knees are no longer considered a contra-indication for unicompartment knee arthroplasty (UKA). The purpose of this study was to determine if patients who had an ACL-deficient knee who underwent lateral UKA had similar mean 10-year outcomes compared to patients who had an ACL-intact knee and lateral UKA. METHODS: Patients who underwent a lateral UKA with ACL deficiency by a single surgeon between 2004 and 2016 were identified. Preoperative magnetic resonance images were utilized to identify a torn or absent ACL in all knees. The absence of an ACL was confirmed during arthroscopy prior to UKA. Patients were matched 1:2 based on age and sex with patients who underwent lateral UKA with an ACL intact knee. The primary patient-reported outcome variable was survival without conversion to total knee arthroplasty. Secondary outcomes included Veterans Rand-12, the Lysholm score, the Knee Osteoarthritis Outcome Score activities of daily living subscale, and Sport subscale. A power analysis showed that 14 patients were needed to identify differences of 10 points on the Knee Osteoarthritis Outcome Score with a power of 80% (P = .05). RESULTS: The cohort of patients who had an ACL-deficient lateral UKA included 4 men and 12 women (43 to 82 years of age). The matched control group included 32 patients. The mean age of both groups was 67 years (range, 43 to 85). There were 2 patients in the ACL-deficient group who failed. At 10 years, survivorship in the ACL-deficient group was 85%, while survival in the ACL-intact group was 100% (P = .035). At an average follow-up of 11 years (range, 4 to 19.6), there was no difference in outcome scores between ACL-deficient and ACL-intact patients. CONCLUSION: Fixed-bearing lateral UKA in the ACL-deficient knee resulted in lower survival than patients who had an intact ACL. Patient-reported outcomes were similar in both groups. The ACL-deficient patient who wishes to undergo lateral UKA should be counseled on the lower survival. LEVEL OF EVIDENCE: Level III. Retrospective cohort study.
RESUMEN
Posterolateral corner and arcuate fractures can cause significant disruption to the stability and kinematics of the knee. This study aimed to determine the biomechanical performance of a novel spiked washer (SW) and intramedullary screw technique compared with a tension slide technique (TST) for the repair of arcuate fractures. Sixteen matched fresh-frozen cadaver knees underwent repair. Each specimen underwent transection of the posterolateral corner and lateral capsule along with a proximal fibula osteotomy to simulate an arcuate fracture. Eight specimens underwent repair with a SW technique and 8 underwent repair with a TST. Each specimen underwent cyclic loading followed by load to failure. Gap formation, ultimate load to failure, energy to failure, and stiffness were assessed. The SW technique had significantly less gap formation and higher load to failure. Furthermore, the SW technique had significantly higher stiffness and energy to failure. A SW and screw technique provided a significantly stronger construct with less gap formation when compared with a TST. [Orthopedics. 2024;47(5):e277-e281.].