SLR - December 2016 - Chetapon Nopachinda

Predictors of Nonunion and Infectious Complications in Patients with Posttraumatic Subtalar Arthrodesis

Reference: Dingemans SA, Backes M, Goslings JC, de Jong VM, Luitse JS, Schepers T. Predictors of Nonunion and Infectious Complications in Patients With Posttraumatic Subtalar Arthrodesis. J Orthop Trauma. 2016 Oct;30(10):e331–5.

Scientific Literature Review

Reviewed By: Chetapon Nopachinda, DPM
Residency Program: Montefiore Medical Center, Bronx, New York

Podiatric Relevance: Although arthrodesis of the subtalar joint is a common procedure, it is technically demanding, and high complication rates have been reported. Reported success rates for fusion have varied, and rates of postoperative wound infections remain high. Schepers et al. reported a wide range of success rates of talocalcaneal fusion (65 percent to 100 percent) following primary subtalar arthrodesis. In the literature, known risk factors for nonunion include smoking and diabetes mellitus. This study attempted to identify predictors of both nonunion and infectious complications following posttraumatic subtalar arthrodesis. The union and complication rates were also identified.

Methods: A retrospective review of all patients between January 2000 and May 2015 at a single academic level 1 trauma center with posttraumatic subtalar arthrodesis were identified. Characteristics, including age, ASA Score, body mass index, diabetes mellitus and substance abuse, were identified. Type of primary injury, open or closed characteristics, primary operative or nonoperative treatment and presence of infection following primary treatment were noted. Outcome measures included union or nonunion, time to union and occurrence of postoperative wound infection. Union was defined as a combination of radiologic signs and a clinically fused joint. Postoperative wound infections were classified into superficial or deep, using the U.S. Centers for Disease and Control criteria. Superficial wound infection was defined as wound dehiscence with necrosis and a positive wound culture or other symptoms treated with oral antibiotics. A deep infection was defined as an infection in which surgical debridement and/or intravenous antibiotics was required.

Results: A total number of 93 (96 feet) patients met the inclusion criteria. Union was achieved in 89 percent of patients. In 17 patients (18 percent), a postoperative wound infection occurred, of which two were classified as superficial and 15 as deep. History of diabetes mellitus and substance abuse were not significantly associated with the occurrence of wound infections. There were two identified predictors of a post-op wound infection, which included an open fracture and patients undergoing secondary arthrodesis who had a post-op wound infection following the initial ORIF. Significant predictors of nonunion could not be identified. There was no detectable correlation between wound infection and nonunion. There was no significant correlation with the use of bone graft and union.

Conclusions: The authors could not identify a significant predictor associated with nonunion. Complication rates following subtalar arthrodesis were fairly high, however, comparable with other published reports. The authors were not able to detect a significant relationship between substance abuse or diabetes mellitus and wound infections. This may be attributed to a relatively low number of patients in this particular study. Based on the results of this study, I conclude that union rates for subtalar arthrodesis remain high, which includes the use of bone graft when appropriate. Diabetes mellitus and substance abuse may still be a factor in terms of infectious complications following the procedure.  

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