Complications after patello-femoral versus total knee replacement in the treatment of isolated patello-femoral osteoarthritis. A meta-analysis

Purpose: Both patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA) are successful in treating isolated patellofemoral osteoarthritis, but the complication rates after PFA are concerning. We performed a meta-analysis to compare the incidence of complications, re-operations, and revision following PFA and TKA for patellofemoral osteoarthritis. Methods: We systematically identified publications with patients who underwent PFA or TKA for patellofemoral osteoarthritis with minimum 1.5 year follow-up. Demographics, implant (TKA, first [1G] or second-generation [2G] PFA), complications, and cause of re-operations were extracted. Random-effects meta-analysis was used to pool incidence data, which was compared between groups using logistic regression to adjust for length of follow-up. Results: Twenty-eight observational studies and no randomized trials were included in this meta-analysis, which limits its generalizability. There was a higher likelihood of any re-operation (odds ratio 8.06) and revision (OR 8.11) in PFA compared to TKA. Re-operation (OR 4. 33) and revision (OR 4.93) were more likely in 1G-PFA than 2G-PFA. When comparing 2G-PFA to TKA, there was no significant difference in re-operation, revision, pain, or mechanical complications. Conclusions: Patients who undergo PFA rather than TKA are more likely to experience complications and require re-operation or revision, but subgroup analysis suggests a relation to implant design. There is no significant difference in re-operation, revision, pain, or mechanical complications between 2G-PFA and TKA. Level of evidence: Systematic review of Level III therapeutic studies, Level III.