TEN-YEAR INCIDENCE OF REOPERATION AND PERIPROSTHETIC JOINT INFECTION IN PERIPROSTHETIC PATELLA FRACTURE

Background Periprosthetic patella fractures (PPPF) are the second most common periprosthetic knee fracture, with short-term reoperation rates reported as high as 26-46%. Despite these high rates, there is limited literature regarding long-term outcomes following operative versus nonoperative treatment. This study aimed to characterize reoperation rates following management of PPPF at 10 years post-fracture. Methods Patients with PPPF following unilateral total knee arthroplasty (TKA) were identified using an insurance claims administration database. Patients were grouped by operative or nonoperative management and followed for 1, 5, and 10 years. Reoperation included extensor mechanism reconstruction and any TKA or patella open reduction internal fixation revision. Periprosthetic joint infection (PJI) was also recorded. Chi-square and Fisher's Exact Test compared associations between management strategy and reoperation or PJI. The analysis was repeated in patients matched by age, sex, obesity, Elixhauser-Comorbidity Index, tobacco use, and diabetes. Results Of 3,364 patients with PPPF, 540 remained after matching PPPF and treatment laterality; 480 were managed operatively and 60 nonoperatively. The matched cohort consisted of 70 patients (69% women; mean age, 67 years). Matched reoperation incidence was 14%, 23%, 26% at the 1-, 5-, and 10- year time points respectively, with higher rates observed in the operative group at each time point. Matched PJI incidence was 6%, 11%, and 6% at the respective time points. Although unmatched analyses demonstrated considerable differences in both reoperation and PJI incidence between treatment strategies, these associations were attenuated by matching. Conclusion At the 10 years post-fracture timepoint, PPPFs demonstrate a 26% rate of reoperation and 6% incidence of PJI, substantially exceeding the rates reported in the general TKA population. In this large database study, operative management was associated with higher reoperation rates, with this relationship remaining after adjustment for measured patient characteristics, though attenuated. Outcomes following PPPF management appear to be influenced by both treatment strategy and underlying patient and fracture characteristics, underscoring the need for individualized clinical decision-making.