Predominance of Radiographical Femoral Component Loosening Signs in Total Knee Arthroplasty for Hemophilic Arthropathy.

Abstract

Aim: To compare the frequency and timing of femoral- versus tibial-sided radiographic radiolucencies after posterior-stabilized TKA in people with haemophilia (PwH) versus non-haemophilic controls.

Methods: A retrospective analysis was conducted of all primary posterior-stabilised total knee arthroplasties (TKA) performed in the centre between December 2003 and December 2018. Patients in Group 1 (n = 53) were age- and implant-matched to controls without haemophilia in Group 2 (n = 58). Radiographs were obtained at 3, 6 and annually to 5 years. Loosening was defined as progressive radiolucent lines >1 mm and/or migration/osteolysis, adjudicated by two blinded surgeons.

Results: Mean age at surgery was 35.7 ± 9.2 years in Group 1 and 60.5 ± 11.8 years in Group 2 (p < 0.001). Femoral component loosening occurred in 22.6% of PwH versus 5.2% of controls (p = 0.011), whereas tibial loosening rates were 11.3% versus 8.6% (p = 0.755). Mean time to femoral loosening was 27.6 ± 16.8 months (Group 1) versus 31.3 ± 13.9 months (Group 2; p = 0.788), and to tibial loosening was 20.4 ± 18.2 months versus 9.6 ± 9.5 months (p = 0.134). Cox regression showed no significant hazard difference for femoral loosening (HR 0.99, 95% CI 0.93-1.05; p = 0.693). Post hoc power for detecting femoral loosening differences was ∼80%.

Conclusions: PwH undergoing TKA showed a higher frequency of femoral-sided radiographic radiolucencies. These findings should be interpreted as potential predisposition to early loosening. Tibial findings were comparable between groups.