Factors associated with humeral shaft nonunion.

BACKGROUND: The primary aim was to identify patient and injury factors independently associated with humeral diaphyseal fracture nonunion after nonoperative management. The secondary aim was to determine the effect of management (operative/nonoperative) on nonunion. METHODS: From 2008-2017, a total of 734 humeral shaft fractures (732 consecutive skeletally mature patients) were retrospectively identified from a trauma database. Follow-up was available for 663 fractures (662 patients, 90%) that formed the study cohort. Patient and injury characteristics were recorded. There were 523 patients (79%) managed nonoperatively and 139 (21%) managed operatively. Outcome (union/nonunion) was determined from medical records and radiographs. RESULTS: The median age at injury was 57 (range 16-96) years and 54% (n = 359/662) were female. Median follow-up was 5 (1.2-74) months. Nonunion occurred in 22.7% (n = 119/524) of nonoperatively managed injuries. Multivariate analysis demonstrated preinjury nonsteroidal anti-inflammatory drugs (NSAIDs; odds ratio [OR] 20.58, 95% confidence interval [CI] 2.12-199.48; P = .009) and glenohumeral arthritis (OR 2.44, 95% CI 1.03-5.77; P = .043) were independently associated with an increased risk of nonunion. Operative fixation was independently associated with a lower risk of nonunion (2.9%, n = 4/139) compared with nonoperative management (OR for nonoperative/operative management 9.91, 95% CI 3.25-30.23; P < .001). Based on these findings, 5 patients would need to undergo primary operative fixation in order to avoid 1 nonunion. CONCLUSIONS: Preinjury NSAIDs and glenohumeral arthritis were independently associated with nonunion following nonoperative management of a humeral diaphyseal fracture. Operative fixation was the independent factor most strongly associated with a lower risk of nonunion. Targeting early operative fixation to at-risk patients may reduce the rate of nonunion and the morbidity associated with delayed definitive management.

Fractures of the proximal- and middle-thirds of the humeral shaft should be considered as fragility fractures.

AIMS: The aim of this study was to determine the current incidence and epidemiology of humeral diaphyseal fractures. The secondary aim was to explore variation in patient and injury characteristics by fracture location within the humeral diaphysis. METHODS: Over ten years (2008 to 2017), all adult patients (aged ≥ 16 years) sustaining an acute fracture of the humeral diaphysis managed at the study centre were retrospectively identified from a trauma database. Patient age, sex, medical/social background, injury mechanism, fracture classification, and associated injuries were recorded and analyzed. RESULTS: A total of 900 fractures (typical 88.9%, n = 800/900; pathological 8.3%, n = 75/900; periprosthetic 2.8%, n = 25/900) were identified in 898 patients (mean age 57 years (16 to 97), 55.5% (n = 498/898) female). Overall fracture incidence was 12.6/100,000/year. For patients with a typical fracture (n = 798, mean age 56 years (16 to 96), 55.1% (n = 440/798) female), there was a bimodal distribution in men and unimodal distribution in older women (Type G). A fall from standing was the most common injury mechanism (72.6%, n = 581/800). The majority of fractures involved the middle-third of the diaphysis (47.6%, n = 381/800) followed by the proximal- (30.5%, n = 244/800) and distal-thirds (n = 175/800, 21.9%). In all, 18 injuries (2.3%) were open and a radial nerve palsy occurred in 6.7% (n = 53/795). Fractures involving the proximal- and middle-thirds were more likely to occur in older (p < 0.001), female patients (p < 0.001) with comorbidities (p < 0.001) after a fall from standing (p < 0.001). Proximal-third fractures were also more likely to occur in patients with alcohol excess (p = 0.003) and to be classified as AO-Orthopaedic Trauma Association type B or C injuries (p < 0.001). CONCLUSION: This study updates the incidence and epidemiology of humeral diaphyseal fractures. Important differences in patient and injury characteristics were observed based upon fracture location. Injuries involving the proximal- and middle-thirds of the humeral diaphysis should be considered as fragility fractures. Cite this article: Bone Joint J 2020;102-B(11):1475-1483.