Two cases of deliberate implant mismatch in knee arthroplasty

Cases: Knee arthroplasty is increasingly common with good clinical results. However, there is a cohort of patients whose native knee anatomy may not marry well with standard implants. The current authors describe two cases (one unicompartmental knee arthroplasty (UKA), one total knee arthroplasty (TKA)), during which deliberately implanting an implant designed for the contra-lateral distal femur (TKA) or contralateral femoral condyle (UKA) respectively, led to a better fit than correct-sided implants. Conclusion: The authors share their experience to raise awareness of a potential solution to such an intra-operative challenge and suggest that implant customisation may ultimately address challenges with grossly abnormal native anatomy.