In the December 7, 2016 issue of JBJS, Krause et al. analyze data from a 2013 industry-sponsored RCT to investigate correlations between nonunions of hindfoot/ankle fusions indicated by early postoperative computed tomography (CT) and subsequent functional outcomes. Whether nonunion was assessed by independent readings of those CT scans at 24 weeks or by surgeon composite assessments at 52 weeks, patients with failed healing had lower AOFAS, SF-12, and Foot Function Index scores than those who showed osseous union.
This study suggests that a CT should be obtained from patients who are at least 6 months out from a surgical fusion and are not progressing in terms of activity-related pain and function. Depending on the specific CT findings, a repeat attempt at bone grafting, with the possible addition of bone-graft substitute and/or possible modification of internal fixation, may be warranted to forestall later clinical problems.
Krause et al. imply that trusting plain radiographs that show no indication of fusion failure is not acceptable when patient pain and function do not improve in a timely fashion. Conversely, they conclude that their findings do not support “the concept of an asymptomatic nonunion (i.e., imaging indicating nonunion but the patient doing well),” because nonunions identified early by CT eventually resulted in worse clinical outcomes. The authors also noted that obesity, smoking, and not working increased the risk of nonunion, corroborating findings from earlier studies.
While advanced imaging such as CT is not necessary in foot/ankle fusion patients who are improving in terms of function, pain, and swelling , this study stresses the importance of achieving union following these fusion procedures.
Marc Swiontkowski, MD