Effectiveness of 3D-printed femoral positioning guides in Oxford Unicompartmental Knee Arthroplasty: a randomized controlled trial with femoral mechanical-anatomical angle subgroup analysis.

Study Summary

120 patients with severe medial compartment knee osteoarthritis undergoing Oxford unicompartmental knee arthroplasty (OUKA) were randomized to receive either OUKA using a 3D-printed intramedullary femoral positioning guide or conventional femoral intramedullary localization. The primary outcomes were femoral component valgus/varus angle (FCVA) and femoral component posterior slope angle (FCPSA). Secondary outcomes included operative time, tourniquet time, Hip-Knee-Ankle (HKA) angle, Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and postoperative complications. Outcomes were assessed on postoperative day 3 for radiographic parameters and at 6 months for functional outcomes and complications. Overall, the results of the study revealed that the 3D-printed guide did not improve alignment accuracy in the overall cohort but significantly improved femoral component alignment in patients with femoral mechanical-anatomical angles (FMA) <5° or >7°. The findings suggest that patient-specific 3D-printed guides should be selectively used in patients with extreme femoral anatomy rather than routinely in all OUKA procedures.