SLR - November 2017 - Joel Ang

Fat Graft and Bone Wax Interposition Provides Better Functional Outcomes and Lower Reossification Rates Than Extensor Digitorum Brevis After Calcaneonavicular Coalition Resection

Reference: Masquijo J, Allende V, Torres-Gomez A, Dobbs MB. Fat Graft and Bone Wax Interposition Provides Better Functional Outcomes and Lower Reossification Rates Than Extensor Digitorum Brevis After Calcaneonavicular Coalition Resection. Journal of Pediatric Orthopaedics. 2017 Oct/Nov; 37(7), e427–e431.

Scientific Literature Review

Reviewed By: Joel Ang, DPM
Residency Program: Cambridge Health Alliance, Cambridge, MA

Podiatric Relevance: Calcaneonavicular coalitions are a relatively uncommon pathology of the lower extremity. While conservative modalities may be beneficial, surgical resection of the coalition is often required for symptomatic patients. A high rate of recurrence is associated with calcaneonavicular coalition, and a number of surgical options exist in order to prevent recurrence. This study retrospectively reviews 48 patients who underwent a calcaneonavicular coalition and received either fat graft interposition, bone wax application or an extensor digitorum brevis (EDB) transposition. The recurrence rates and postsurgical functional scores were analyzed to determine which surgical technique would provide improved outcomes.

Methods: A level III retrospective case control study was performed for patients who underwent a calcaneonavicular coalition. A total of 48 patients and 56 feet were included in the study. Fat graft was applied in 23 feet, bone wax in 18 feet, and EDB transposition was performed in 15 feet. The average follow-up time was 35 months. Preoperative and postoperative pain was evaluated using a visual analog scale, and the American Orthopedic Foot and Ankle (AOFAS) score was used to measure functional outcomes. Radiographic and clinical recurrence was also analyzed. A resection gap of less than 50 percent on radiographs was deemed radiographic recurrence, while pain with ambulation at the coalition site was deemed a clinical recurrence.

Results: Pain scores and AOFAS scores improved significantly in all three groups; however, the improvement for both scores were noted to be lower in the EDB group. Eight feet were noted to have radiographic recurrence, six of which were in the EDB group. Five feet were noted to have clinical recurrence, all of which were in the EDB group. Two feet with recurrence required revision surgery, while the remaining three were treated conservatively. There were three wound-related complications in the fat graft group.

Conclusions: The authors conclude that the utilization of fat graft or bone wax provided better functional outcomes, pain relief and lower recurrence rates in comparison to EDB transposition. One anatomic study suggests that EDB muscle is not long enough to reach the plantar aspect of the postresection defect, thereby explaining the high rate of complications. With regards to fat graft harvest site complications, the authors suggest obtaining fat from the posteromedial buttock crease instead of the posterior crease due to concerns about skin tension. The retrospective nature, small sample size and uneven treatment group size of the study does limit its conclusions. Nevertheless, the study may encourage surgeons to consider methods other than EDB transposition for treatment of calcaneonavicular coalitions.   

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