The effects of patello-femoral arthrosis to the outcome of unicompartmental arthroplasty

PURPOSE: Unicompartmental knee arthroplasty is developed for the treatment of unicompartment arthrosis. Participation of multi compartments to the disease and patello-femoral arthrosis classically form a contraindication for this surgery. Different opinions were reported in literature on this subject. In this study, the effects of the presence of patello-femoral arthrosis on post-operative clinical and functional outcomes and revision process were investigated. METHOD: Pre-operative magnetic resonance (MR) images of 52 patients undergone medial unicompartmental knee arthroplasty between the years of 2011-2016 who completed minimum 6 months of follow-up period were evaluated. According to the presence of patello-femoral arthrosis, patients were classified into groups as non-arthrosis, grade 1-2 and grade 3-4. Statistical comparison were performed on knee society score (KSS), functional knee society score (fKSS), Oxford knee score (OKS), visual analog scale (VAS) score and post-operative joint range of motion (ROM) results. RESULTS: 24 of 52 patients had no patello-femoral arthrosis. 13 patients were diagnosed with grade 1-2 and 15 patients were diagnosed with grade 3-4 patello-femoral arthrosis. No statistically significant difference was observed in patello-femoral arthrosis groups in average post-operative KSS, fKSS, OKS, VAS values. No revision proceeding was demonstrated in regression analysis. CONCLUSION: The results obtained from this study demonstrated that patello-femoral arthrosis has no effect on clinical and functional results. Yet, it is also considered that there is no factor to affect the implant survival rate. Having that said, when the number of patients and relatively short follow-up periods are considered, it is our opinion that new studies are required in this matter.