The use of a vascularized distal radial graft based on the 1,2 intercompartmental artery has been reported to be successful in scaphoid nonunions. While several studies have demonstrated high rates of union, the authors recently reported an overall union rate of 71% for scaphoid nonunions and a rate of 50% in the setting of osteonecrosis. The use of a free, vascularized medial femoral condyle bone graft was first described by Doi et al., who reported successful union in ten patients at an average of twelve weeks postoperatively. The purpose of the present study was to evaluate these two treatment methods in a series of scaphoid waist nonunions with an avascular proximal pole and carpal collapse.
The diagnosis of osteonecrosis was ultimately confirmed at the time of surgery by the absence of punctate bleeding on tourniquet release. The study was a retrospective review conducted at two institutions between January of 1994 and June of 2006. Twenty-two nonunions were identified. Ten were treated with distal radial pedicle vascularized grafts and twelve with free vascularized medial femoral condyle grafts. Ten patients had prior surgical treatment and nine of the twenty-two patients reported smoking tobacco. In patients receiving the free vascularized medial femoral condyle graft, a volar approach to the scaphoid was used and the carpal alignment was restored. The pedicle was anastomosed to the radial artery in an end-to-side fashion.
Of the ten nonunions treated with the 1,2 intercompartmental supraretinacular artery pedicle, four united at a median of nineteen weeks. There were six failures. In the patients undergoing the free vascularized medial femoral condyle graft, all twelve nonunions united at a median of thirteen weeks after surgery (P < 0.05). All patients reported knee pain at the site of the medial femoral condyle harvest that resolved in an average of six weeks. Differences in postoperative revised carpal height indices, scapholunate angles, and radiolunate angles between the groups did not reach significance. The authors conclude that a vascularized graft from the medial femoral condyle is the recommended treatment for a scaphoid waist nonunion with avascularity of the proximal pole and carpal collapse.
This study has several limitations. It was retrospective and there were multiple surgeons and relatively small numbers of patients in each group. The relative rarity of the combination of scaphoid waist nonunion with an avascular proximal pole and carpal collapse (humpback deformity) and patient variability makes the comparison of multiple techniques challenging. However, the use of this technique, at least in the select group of scaphoid nonunions with humpback collapse and osteonecrosis, appears promising. The procedure will have to be further explored and expanded to a larger number of patients before we consider it the answer to all of our scaphoid nonunion problems.