OBJECTIVES: 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. Our study characterized femoral and tibial fractures and evaluated risk of non-union.

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. Outcomes included: non-union in the 2-years post-index, 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.