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. 2022 Oct;51(7):1087-1095.
doi: 10.1111/vsu.13880. Epub 2022 Aug 27.

Delayed union, non-union and mal-union in 442 dogs

William George Marshall  1 , Barbro Filliquist  2 , Emmanouil Tzimtzimis  1 , Agnieszka Fracka  1 , Jose Miquel  1 , Javier Garcia  1 , Maria Dalla Fontana  1
Affiliations

Delayed union, non-union and mal-union in 442 dogs

William George Marshall et al. Vet Surg. 2022 Oct.

Abstract

Objectives: (1) To estimate the prevalence of delayed union, non-union and mal-union in canine fractures; (2) to describe fracture, demographic, and treatment characteristics for these outcomes; (3) to identify risk factors for delayed or non-union.

Study design: Retrospective study.

Sample population: Four hundred and forty two dogs (461 fractures).

Methods: A review was conducted of clinical records and radiographs from 2 teaching hospitals. "Union," "delayed union," "non-union" and "mal-union" were defined, and fracture, demographic, treatment, and outcome variables described. Differences in proportions or medians between "union," "delayed union" and "non-union" were tested using χ2 and Mann-Whitney U-tests for categorical and continuous variables respectively. Potential explanatory variables for "delayed or non-union" were tested using logistic regression to identify risk factors.

Results: Median radiographic follow up was 53 days (14-282). Delayed union occurred in 13.9% of fractures (64/461), non-union in 4.6% (21/461), and mal-union in 0.7% (3/461). Risk factors for delayed or non-union were age (OR 1.21, 95% CI 1.12-1.31); comminuted fracture (OR 4.24, 95% CI 2.4-7.5); treatment with bone graft (all types) (OR 3.32, 95% CI 1.3-8.5); surgical site infection (OR 3.24, 95% CI 1.17-8.97), and major implant failure (OR 12.94, 95% CI 5.06-33.1).

Conclusion: Older dogs, dogs with comminuted fractures, surgical site infection, or major implant failure were at increased odds of delayed or non-union. Radius and ulna fractures in toy breed dogs were not at increased odds of delayed or non-union.

Clinical significance: The identified risk factors should inform fracture planning and prognosticating. The prognosis for radial fractures in toy breeds appears better than historically believed.

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Conflict of interest statement

The authors declare no conflicts of interest related to this report.

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