UCSF

Background

Complex hindfoot pathology may benefit from vascularized bone flap reconstruction rather than traditional bone grafting techniques. Medial femoral condyle (MFC) flaps provide vascularized periosteum, skin, and corticocancellous bone.

Methods

A retrospective, single-institution cohort study of consecutive MFC flaps performed for complicated hindfoot reconstruction between 2013 and 2019 was reviewed. Radiologic follow-up assessed osseous union and clinical outcomes were evaluated with the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score. Thirty MFC flaps were performed in 28 patients for complex hindfoot pathology. Twenty-seven flaps had adequate clinical and radiographic follow-up (mean 15.8 months).

Results

The majority presented with avascular necrosis (83%) and failed prior operations (67%, mean 3.1). Most hindfoot procedures involved arthrodesis (n = 24, 80%); tibiotalocalcaneal (n = 11) and talonavicular (n = 7) most frequently. Mean osseous flap volume was 10.3 cm³ (range 1.7-18.4 cm³); one flap required takeback for venous congestion but no total flap losses occurred. Primary osseous union was initially achieved in 20 patients (74%, mean 217 days). Six flaps developed interface nonunion; 5 underwent revision arthrodesis and ultimately achieved union in 24/27 flaps (89%, mean 271 days). Risk factors for nonunion were body mass index (BMI) >30 (P = .017) and prior arthrodesis (P = .042). Mean AOFAS hindfoot scores increased significantly from 52.3 preoperatively to 70.7 postoperatively (P < .001). Subscore analysis demonstrated significant improvement in postoperative pain scores from 14.2 to 27.3 out of 40 (P < .001).

Conclusion

The MFC free flap provided vascularized bone for complicated foot and ankle reconstruction with relatively low donor site morbidity, promising osseous union results, and improved functional outcomes.

Level of evidence

Level IV, retrospective case series.