gms | German Medical Science

Objectives/Interrogation: Non-union after operative treatment of an ulnar fracture is very uncommon. There are severely disabling and challenging to treat. Multiple factors have been associated with the establishment of this non-union. Many non-unions are associated with soft tissue damage, fracture site vascularity, persistent instability, infection, and the surgical treatment technique. This study analysed the systemic conditions and local factors associated with the failure of bone fracture healing.

The aim of our study was to identify the risk factors for ulnar nonunion.

Methods: We retrospectively reviewed a cohort of ulnar fractures treated surgically with open reduction and internal fixation (ORIF), during a period of 10 years (2007-2016). We identified 211 ulnar fractures, 16 distal, 52 diaphyseal, 143 proximal. All patients had a minimum follow-up of 1 year. We defined non-union if there was no radiological consolidation of the fracture after this period, and we classified them according to Weber classification. We assessed risk factors like: fracture site vascularity, surgical treatment technique, biological factors of the patient, and the fracture's mechanism. Data were analysed using SPSS software system version 21. Multivariate regression analysis was performed to assess independent risk factors of ulnar non-union. Chi square test or Fisher exact test was used to compare categorical measurements. Statistical significance was considered as p less than 0.05.

Results and Conclusions: We found 17 ulnar non-union (8,1%), 13 diaphyseal and proximal ulna (6,2%). The 94% were hypertrophic non-union, and 6% of atrophic non-union. There were 12 male and 5 female. The mechanism of the fractures was high-energy traumatism in 30%. The 30% of patients smoked, 10,4% have diabetes mellitus, the 40,7% have vascular pathology. The fractures were open in 15,2%, the 72,5% were isolated ulnar fracture, the 25,6% were comminuted. We analyzed the ORIF and the 93,8% were well done (according to AO principles). We obtained statistically significant results in the relationship of high-energy injuries (p=0,0001), comminution (p=0,0001) and suboptimal fixation of the fracture (p=0,013), with the risk of developing nonunion. We didn't find statistically significant results in relation to the others clinical data analyzed.

Our results showed that a high-energy injury, a comminuted fracture, and a suboptimal treatment of the fracture, are risk factors of an ulnar nonunion.