JBJS Editor’s Choice—Nonunions of Foot/Ankle Fusions Matter

Ankle_Fusion_12_7_16.pngIn 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
JBJS Editor-in-Chief

One thought on “JBJS Editor’s Choice—Nonunions of Foot/Ankle Fusions Matter

  1. Non-union? Says who?

    Although assessing bone union is a large part of what orthopaedic surgeons do, it is still a controversial issue.

    In their article, Krause et al. wrote: “Nonunion was defined by 2 methods. The first relied exclusively on blinded review of CT scans at 24 weeks by the independent radiologist. Union was defined as ≥25% osseous bridging across the articulation, as that had been demonstrated to be associated with clinically important improvement. Second, nonunion was defined at 1 year by the treating surgeon on the basis of a composite evaluation of (1) CT scans at 24 or 36 weeks with union defined as ≥50% osseous bridging across the articulation, (2) radiographs at 1 year with osseous union defined as osseous bridging across at least 3 of 4 predefined aspects (anterior, posterior, medial, and lateral) and disappearance of the joint space, and (3) clinical findings at 1 year, based on a global assessment at both the full joint level (i.e., considering the full complement of fusion sites) and the individual joint level (i.e., considering every joint independently), with therapeutic failure defined as any symptomatic nonunion or delayed union that required secondary therapeutic intervention. Radiographs and CT scans in isolation were not considered diagnostic and were only used in the context of clinical findings. Using this composite evaluation, the treating surgeon determined that there was union (Figs. 2 and 3), evidence of progressive healing, or nonunion (Figs. 4 and 5). Evidence of progressive healing and nonunion were both considered nonunion for this study. For both assessments of union, patients with concomitant arthrodeses of >1 joint (i.e., double or triple arthrodesis) were considered to have a nonunion if any of the joints were ununited.”

    Many will agree with certain aspect of these criteria, but not with others. Those dealing with fracture union may have different opinions (1, 2) but are they applicable to arthrodesis? Even among researchers of foot and ankle arthrodesis, opinions differ. For example, Coughlin and Jones described somewhat different focuses in various papers (3).

    So at the end of the day, pick a card, any card–as long as you stick with it.

    1. https://www.hindawi.com/journals/amed/2014/708574/
    2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663323/
    3. http://www.nofafoundation.org/pdf/The-Evaluation-of-Bone-Union.pdf

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