Prior osteosynthesis—unlike osteotomy—raises revision risk after total knee arthroplasty, predominantly via periprosthetic infection

Abstract Purpose Previous knee surgery is discussed as a risk factor for total knee arthroplasty (TKA), yet most reports do not distinguish between osteotomy and osteosynthesis. The German Operationen‐ und Prozedurenschlüssel (OPS)‐based classification was used to compare the impact of these procedures on implant survival, mortality and complications after primary TKA. Methods Data from the German Arthroplasty Registry (2012–2024) were used. Patients with prior osteosynthesis ( n = 10,078) and prior osteotomy ( n = 96,782) were each 1:1 Mahalanobis‐matched to controls without prior knee surgery (matching on age, sex, Elixhauser score, body mass index BMI, fixation, arthroplasty type and bearing mobility). Primary endpoints were all‐cause revision and mortality; secondary endpoints were periprosthetic joint infection (PJI), periprosthetic fracture and aseptic loosening. Kaplan–Meier with 95% log–log confidence intervals (CI) and log‐rank tests were used; Cox proportional hazards models estimated hazard ratios (HRs). Results All‐cause revision differed for osteosynthesis versus controls (log‐rank p < 0.001) but not for osteotomy ( p = 0.972). In Cox models, prior osteosynthesis was associated with a higher revision hazard (HR 1.81, 95% CI 1.52–2.15; p < 0.001). For osteotomy, no increased revision hazard was observed across age (<65/≥65 years) or comorbidity (Elixhauser < 3/≥3) strata. Mortality was higher after osteosynthesis (HR 1.48, 95% CI 1.34–1.64; p < 0.001), while osteotomy showed no overall increase; PJI occurred more often after osteosynthesis (HR 1.62, 95% CI 1.21–2.19). Periprosthetic fracture (HR 8.54, 95% CI 3.02–24.1) and aseptic loosening (HR 2.38, 95% CI 1.24–4.59) were likewise increased after osteosynthesis. Conclusions Prior osteosynthesis increases revision risk after TKA—predominantly via infection—whereas prior osteotomy does not. These findings support extended perioperative infection workup, staged hardware removal when indicated and careful implant selection in patients with prior osteosynthesis; outcomes after osteotomy are comparable to primary osteoarthritis. Level of Evidence Level IV, retrospective observational study.