The Role of Medial Femoral Condyle Free Vascularized Bone Graft for the Treatment of Failed Scaphoid Nonunion Surgery associated with Proximal Pole Avascular Necrosis
Nicholas Pulos, MD; Kathleen M. Kollitz, MD; Allen T. Bishop, MD; Alexander Y. Shin, MD
Mayo Clinic, Rochester, MN
Hypothesis: Revision surgery for scaphoid nonunions with avascular necrosis presents a particularly challenging problem. The purpose of this study is to determine the outcome of free-vascularized medial femoral condyle bone grafts in the treatment of revision surgery for scaphoid nonunions with avascular necrosis. We hypothesize that this treatment restores scaphoid vascularity and architecture in patients after prior failed surgery for scaphoid nonunions.
Methods: A retrospective review was conducted to identify all patients with scaphoid nonunions with avascular necrosis who had failed prior operative treatment and subsequently treated with a medial femoral condyle bone graft in the revision setting. Between May of 2005 and September of 2016, 49 patients were identified. Mean time from previous surgery to revision was 15.3 months. Thirty-six patients had a prior bone grafting procedure. All patients had documented avascular necrosis of the proximal pole at the time of surgery evaluated by deflation of the tourniquet and lack of bleeding of the proximal pole. Carpal indices, time to union, early functional outcomes and complications were recorded.
Results: Of the 49 patients treated with medial femoral condyle bone grafting, 41 healed (83.7%) at a mean of 15.9 weeks (range, 9 to 31 weeks). Radiographic evaluation demonstrated significant improvement from preoperative to postoperative mean revised carpal height ratio (1.46 and 1.49, respectively; p = 0.04), scaphoid height to length ratio (0.70 and 0.61, respectively, p < 0.0001), lateral scaphoid angle (28.3 and 14.6 degrees, respectively, p < 0.0001), scapholunate angle (66.2 and 58.4 degrees, respectively, p < 0.0001), and radiolunate angle (20.0 and 10.1 degrees, respectively, p < 0.0001). 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 subsequent procedures of which 21 were planned (21 planned Kirschner wire removals, 1 revision Kirschner wire placement, 5 scaphoidectomies with partial wrist fusions, 1 radial styloidectomy, 1 screw removal). There were two postoperative knee infections, but no patients complained of knee pain at final follow-up. Neither age, smoking status, BMI, time to surgery, nor pre-operative radiographic findings were found to be statistically significant predictors of failure.
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