No difference in survivorship after unicompartmental knee arthroplasty with or without an intact anterior cruciate ligament

Purpose Anterior cruciate ligament deficiency (ACLD) has been considered a contraindication for Oxford unicompartmental knee arthroplasty (UKA) because of the reported higher incidence of failure when implanted in ACLD knees. However, given the potential advantages of UKA over total knee arthroplasty (TKA), we have performed UKA in a limited number of patients with ACL deficiency and end-stage medial compartment osteoarthritis (OA) over the past 11 years. The primary aim of this study was to establish the clinical outcome of this cohort; the secondary aim was to compare both clinical and radiographic data with a matched cohort of ACL-intact (ACLI) patients who have undergone UKA for anteromedial OA. Methods This retrospective observational study describes the clinical and radiological outcome in 46 medial Oxford UKAs implanted in 42 consecutive patients with ACL deficiency and concomitant symptomatic medial compartment OA at mean follow-up of 5 years. It also compares the outcomes with a matched cohort of UKA patients with an intact ACL (ACLI group). Results At the time of last follow-up, there was no significant difference in clinical results or survivorship between the two groups in this study. Conclusion The successful short-term results of the ACLD group suggest ACL deficiency may not always be a contraindication to Oxford UKA as previously thought. Until long-term data is available, however, we maintain our recommendation that ACLD be considered a contraindication. Level of evidence III.