Variables Prognostic for Delayed Union and Nonunion Following Ulnar Shortening Fixed With a Dedicated Osteotomy Plate.

PURPOSE To examine potential risk factors for the development of delayed or nonunion following elective ulnar shortening osteotomy using a dedicated osteotomy plating system. METHODS We performed a retrospective review of all patients who underwent elective ulnar shortening using the TriMed single osteotomy dynamic compression plating system by 1 of 2 fellowship-trained hand surgeons over a 5-year period. Demographic data and medical, surgical, and social histories were reviewed. Time to bony union was determined radiographically by a blinded reviewer. Bivariate statistical analysis was performed to examine the effect of explanatory variables on the time to union and the incidence of delayed or nonunion. Those variables associated with the development of delayed or nonunion were used in a multivariate logistic regression model. Complications, including the need for additional surgery, were also recorded. RESULTS Seventy-two ulnar shortening osteotomy procedures were performed in 69 patients. Delayed union, defined as ≥ 6 months to union, occurred in 8 of 72 cases (11%). Of 72 surgeries, 4 (6%) resulted in nonunions, all of which required additional surgery. Hardware removal was performed in 13 of 72 (18%) of the cases. Time to union was significantly increased in smokers (6 ± 3 months) versus nonsmokers (3 ± 1 months). On multivariable analysis, diabetics and active smokers demonstrated a significantly higher risk of developing delayed union or nonunion. Patient age, sex, body mass index, thyroid disease, worker's compensation status, alcohol use, and amount smoked daily did not have an effect on the time to union or the incidence of delayed or nonunion. CONCLUSIONS Despite the use of an osteotomy-specific plating system, smokers and diabetics were at significantly higher risk for both delayed union and nonunion following elective ulnar shortening osteotomy. Other known risk factors for suboptimal bony healing were not found to have a deleterious effect.