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

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.

Bioengineering an Osteoinductive Treatment for Bone Healing Disorders: A Small Animal Case Series

“…This case had a massive radial defect that was filled with graft materials (►Fig. 3), and on mRUST scoring neither observer was convinced of radiographic healing. The clinician's contrary radiographic assessment was probably biased by an encouraging clinical picture.…”

“…Fractures in an estimated 3.4 to 4.6% of dogs and cats fail to heal. 1 2 3 Recombinant human bone morphogenetic protein-2 (rhBMP-2) is an osteoinductive growth factor used to treat fracture non-union in dogs, cats and humans. 4 5 6 7 8 9 In veterinary reports, collagen sponges, 4 6 ceramics, 5 or combinations thereof, 7 were soaked in rhBMP-2 of concentration 200 µg/mL, 6 7 500 µg/mL 5 or 1,500 µg/mL, 4 and implanted at the injury site.…”

Feline radial and ulnar diaphyseal fractures: a retrospective study of 49 cases comparing single bone fixation and dual bone fixation

“…The rate of non-union in the radius and ulna in cats is 16.7%, compared with dogs, in which 17.9% of radius and ulna fractures result in delayed union and there is a non-union rate of 3.4%. 11,13 This may be due to the increased motion in the forelimb of cats compared with dogs, with cats having almost double the range of supination. 1,9,11 The range of feline antebrachial rotation is most similar to that of humans.…”

Long‐term outcomes of atrophic/oligotrophic non‐unions in dogs and cats treated with autologous iliac corticocancellous bone graft and circular external skeletal fixation: 19 cases (2014‐2021)

“…This study demonstrates the feasibility of a novel technique for the treatment of atrophic/oligotrophic non‐unions of radius/ulna and tibia/fibula in dogs and cats. Surgical treatment in this cohort was successful in 94.7% of patients; this is comparable to that of previous studies and lies between the previously described 43% and 100% (Marshall et al ., 2022; Massie et al ., 2017; Munakata et al ., 2018). One study reported a 100% success rate using frozen cortical bone allografts in 15 dogs with radius and ulna non‐union (Munakata et al ., 2018).…”

“…Similarly, efforts have been made in the veterinary community to better understand the complications of fracture healing and related predisposing factors. A recent retrospective study analysed complications in fracture healing in 442 dogs (461 fractures) and reported a non‐union prevalence of 4.6% (Marshall et al ., 2022). The reported predisposing factors for non‐unions were older age, comminuted fractures, infections and implant failure; however, no correlation was found between the development of non‐union and breed.…”