The Role of Medial Femoral Condyle Free Vascularized Bone Graft for the Treatment of Failed Scaphoid Nonunion Surgery associated with Proximal Pole Avascular Necrosis

Abstract

There is no financial information to disclose. Revision surgery for scaphoid nonunions with proximal pole avascular necrosis is a challenge. We hypothesize that the use of free-vascularized medial femoral condyle bone grafts can heal the bone, revascularize the proximal pole, and restore scaphoid architecture, resulting in acceptable functional outcomes. We retrospectively reviewed patients who had failed prior operative treatment for a scaphoid nonunion and proximal pole avascular necrosis. Between May of 2005 and September of 2016, 49 patients were identified with this preoperative diagnosis and subsequent treatment with a medial femoral condylar free vascularized bone flap. Mean time from injury to revision surgery was 24 months, and a mean 15 months following the initial surgery. Of the 49 patients, 36 had a prior bone graft procedure and 6 patients had two previous surgeries. Initial internal fixation was with a scaphoid screw in 43 patients and K-wires alone in 3. All patients had documented avascular necrosis of the proximal pole at the time of our surgery, defined by complete absence of punctate bleeding of the proximal pole with the tourniquet deflated. Carpal indices, time to union, functional outcomes and complications were recorded. Forty-one of 49 previously operated on scaphoid nonunions healed (84%) at a mean of 16 weeks (range, 9 to 31 weeks) based upon CT scan imaging. Radiographs demonstrated significant improvement in carpal alignment following surgery, as determined by the lateral scaphoid angle, scapholunate angle, radiolunate angle, scaphoid height to length ratio and carpal height ratio. There was a trend towards improved grip strength and no significant change in total wrist range of motion pre- and postoperatively. Twenty-nine patients underwent 21 subsequent planned procedures (removal of buried K wires). There were two superficial postoperative donor site infections, however no patients complained of medial thigh pain at final follow-up. Age, smoking status, BMI, time to surgery, or preoperative radiographic findings were not found to be statistically significant predictors of failure. •We present the largest series to date of patients who have undergone revision scaphoid nonunion surgery with documented avascular necrosis of the proximal pole.•84% of patients who had failed prior scaphoid nonunion surgery healed at a mean of 16 weeks after treatment with free-vascularized medial femoral condyle grafts.