Functional outcome of four-corner arthrodesis for treatment of grade IV scaphoid non-union.

Functional limitations and pain are end results of scaphoid nonunion with progressive carpal collapse and radiocarpal arthritis. The aim of this study was to assess the functional outcome of four-corner arthrodesis with scaphoidectomy for the treatment of grade IV scaphoid nonunion with Scaphoid Nonunion Advanced Collapse (SNAC) stages II and III. Ten patients with symptomatic grade IV non union of the scaphoid and a mean duration of non unions of 12.1 +/- 2.81 months were treated using the four-corner arthrodesis technique. A dorsal midline longitudinal approach centered over the third metacarpal-capitate-lunate-radius axis, excision of the scaphoid, neutral alignment of the remaining carpal bones, and arthrodesis of the capitate, hamate, lunate, and triquetrum, were performed. Kirschner wires were used to secure the arthrodesis in all cases. A below-elbow thumb spica cast was applied for 3 months. Follow up period ranged from 8 to 24 months, with a mean of 16 +/- 4.7 months. All patients were assessed both functionally for pain, range of motion and grip strength, and radiographically for evidence of fusion and carpal alignment. Good results were achieved in 7 patients (70%) according to the modified Mayo Wrist Scoring Chart. There were no intraoperative complications. Postoperatively, one patient suffered superficial wound infection One patient showed dorsal impingement of the capitate and radius. Also, two patients suffered reflex sympathetic dystrophy. No patients showed deep infection or nonunion. The Four-corner Arthrodesis technique is a motion-sparing, limited arthrodesis that reliably results in pain relief, improved grip strength, and overall patient satisfaction with low associated non union and complication rates.