Associate Director, Epidemiology Johnson & Johnson, United States
Background: Non-union is a common complication of femoral and tibial fractures, however risk of non-union is not consistent across all types of femoral or tibial fractures.
Objectives: Characterize femoral and tibial fractures, and evaluate risk of non-union, specific to fracture anatomy and characteristics.
Methods: Data: The IBM® MarketScan® Commercial Claims and Encounters database was used for this analysis. Patients with surgically-treated femur or tibia fractures, from Q4 2015 to most recent, were identified. Exclusion criteria included: polytrauma and amputation at index. Patients were categorized based on fracture location, for femoral fractures: neck, trochanteric, shaft or condylar; for tibial fractures: condylar, other proximal (including physeal and Salter Harris), shaft, pilon and malleolus, other distal. Patients with fractures in unspecified locations, or multiple femoral or tibial locations were excluded. The primary outcome was non-union in the 2-years post-index. Additional outcomes included concurrent infection, and reoperation. Age, gender, comorbidities, fracture characteristics and severity were identified for all patients. Crude and adjusted rates of non-union (using Poisson regressions with log link) were calculated.
Results: 7,128 and 6,227 patients with surgically-treated femoral and tibial fractures were identified. The 2-year cumulative non-union hazard in patients with femoral condylar, shaft, trochanteric or neck fractures was 9.8% (7.0%-12.6%), 9.0% (7.8%-10.2%), 6.9% (5.3%-8.5%) and 6.0% (4.9%-7.0%), respectively. In the tibial cohort, shaft, distal, pilon or malleolus, condylar and other proximal fractures had non-union rates of 10.8% (9.2%-12.3%), 8.1% (95%CI: 4.7%-11.4%), 5.2% (4.3%-6.1%), 2.4% (1.5%-3.3%) and 2.2% (0.0%-4.6%), respectively. Risk ratios (RR) for non-union were significantly elevated in patients with shaft vs other fractures (femur: RR = 2.36 (1.82-3.06); tibia: RR = 1.95 (1.47-2.57)) and patients with Gustilo III (vs closed) fractures (femur: RR = 1.96 (1.47-2.61); tibia: RR = 3.33 (2.85-3.88)). Patient comorbidities had a lesser impact on non-union risk.
Conclusions: Risk of non-union varies by level of the femur or tibial fracture with the highest risk observed in open shaft fractures.
