Acute or Delayed TKA for Tibial Plateau Fracture? An Observational Study From the Swedish Arthroplasty Register.

backgroundAcute TKA has been proposed as an alternative to open reduction and internal fixation for complex tibial plateau fractures in patients who are older and who have compromised bone quality. The alternative is a delayed TKA after primary fracture management with an unfavorable outcome. However, the long-term outcomes and risk for reoperation after acute TKA compared with delayed TKA for fracture sequelae remain unclear. QUESTIONS/PURPOSES: When comparing acute TKA (< 3 months after injury) for tibial plateau fracture with delayed TKA for fracture sequelae, we asked: (1) Do the risks of reoperation or revision for any cause differ? (2) Do the risks of reoperation or revision for infection differ? (3) Do the risks of reoperation or revision for loosening differ?

methodsData for all TKAs performed between 2014 and 2023 with the indication of acute tibial plateau fracture (n = 152) or fracture sequelae (n = 950) were extracted from the Swedish Arthroplasty Register. Patients who underwent TKA for acute tibial plateau fractures were older (73 versus 66 years), more often women (78% [118 of 152] versus 57% [539 of 950]), had lower BMI (26.7 versus 27.9 kg/m 2 ), and received constrained or hinged implants more frequently (59% [89 of 152] versus 33% [311 of 950]). Reoperations were identified in the Swedish Arthroplasty Register through subsequent procedures on the index knee and classified as reoperations (where the implant remained in situ) or revisions (with exchange, addition, or removal of components). When bilateral procedures occurred within the study period, only the first TKA was retained to ensure independence of observations. Loss to follow-up because of emigration or incomplete revision reporting was expected to be minimal, as the Swedish Arthroplasty Register captures approximately 98% of primary TKAs and 94% of revisions nationally. We estimated the cumulative event probability of secondary procedures using the Kaplan-Meier method and used logistic regression models to estimate adjusted ORs for (1) any reoperation or revision, (2) infection-related procedures, and (3) loosening-related procedures, adjusting for age, gender, and BMI. Because implant type reflects the underlying clinical situation and cannot be reliably adjusted for, it was reported descriptively.

resultsDuring follow-up, 7% (78 of 1102) of patients underwent a reoperation and 5% (60 of 1102) of patients underwent a revision. At 5 years, the cumulative event probability of any revision was 8% (95% confidence interval [CI] 2% to 14%) for acute TKA and 5% (95% CI 4% to 7%) for delayed TKA (p = 0.41). For reoperations, the cumulative event probability at 5 years was 9% (95% CI 3% to 15%) for acute TKA and 7% (95% CI 5% to 9%) in the delayed TKA group (p = 0.26). After adjusting for age, gender, and BMI, there was no difference between groups in odds for any reoperation (OR 0.76 [95% CI 0.38 to 1.5]; p = 0.43) or any revision (OR 0.68 [95% CI 0.31 to 1.5]; p = 0.32). Infections accounted for 9% (1 of 11) of reoperations for acute TKAs and 40% (27 of 67) of delayed TKAs. At 5 years, the cumulative event probability of reoperation or revision due to infection was 2% (95% CI 0% to 5%) for acute TKA and 3% (95% CI 2% to 4%) for delayed TKA (p = 0.06). There was no difference in the adjusted odds of infection-related reoperation (OR 3.7 [95% CI 0.48 to 28]; p = 0.21) or infection-related revision (OR 3.0 [95% CI 0.40 to 23]; p = 0.28). Loosening accounted for 27% (3 of 11) of revisions after acute TKAs and 9% (6 of 67) after delayed TKAs. At 5 years, the cumulative event probability of loosening-related revision was 2.9% (95% CI 0% to 7.1%) for acute TKAs and 0.6% (95% CI 0.1% to 1.2%) for delayed TKAs (p = 0.50). The adjusted odds of loosening-related revision were lower for delayed TKAs (OR 0.21 [95% CI 0.05 to 0.97]; p = 0.045).

conclusionThe timing and pattern of revision differ between the two investigated groups, with delayed TKAs undergoing unplanned reoperation or revision earlier and with a higher proportion of infection-related revisions, whereas acute TKAs underwent reoperation or revision later and with a higher proportion of revisions for mechanical loosening. In the absence of large prospective trials, future observational work should include evaluation of pre- and postoperative radiographs and patient-reported outcomes, to determine which patients may benefit from acute TKA for tibial plateau fracture. LEVEL OF EVIDENCE: Level III, therapeutic study.