Treatment of scaphoid waist nonunions with an avascular proximal pole and carpal collapse. Surgical technique.

BACKGROUND Surgically, it is difficult to achieve union of a scaphoid nonunion that is associated with osteonecrosis of the proximal pole, and those with carpal collapse are especially difficult to treat. A variety of vascularized bone grafts can be used. The purpose of this study was to compare the effectiveness of two types of vascularized bone graft -- a distal radial pedicle graft and a free vascularized medial femoral condyle graft -- in the treatment of scaphoid waist nonunions associated with proximal pole osteonecrosis and carpal collapse. METHODS A retrospective review was conducted at two institutions to identify all patients with a scaphoid waist nonunion associated with an avascular proximal pole and carpal collapse. Between January 1994 and June 2006, twenty-two such nonunions were identified in twenty-two patients. Ten were treated with a distal radial pedicle vascularized graft and twelve, with a free vascularized medial femoral condyle graft. Patient demographics were similar between the groups, and the duration of follow-up averaged twelve months. Union was determined with use of plain radiographs and computed tomography or trispiral tomograms. In addition, carpal angles, time to union, union rates, and complications were recorded. RESULTS Four of the ten nonunions treated with the distal radial pedicle graft healed, at a median of nineteen weeks, and all twelve nonunions treated with the free medial femoral condyle graft healed, at a median of thirteen weeks. The rate of union was significantly higher (p = 0.005) and the median time to healing was significantly shorter (p < 0.001) for the nonunions treated with the medial femoral condyle graft. CONCLUSIONS A vascularized interposition graft from the medial femoral condyle is the recommended vascularized bone graft for the surgical treatment of scaphoid waist nonunion with avascularity of the proximal pole and carpal collapse.