Scaphotrapeziotrapezoid Arthrodesis and Lunate Excision for Advanced Kienböck Disease

Abstract

To analyze the outcomes of lunate excision combined with scaphotrapeziotrapezoid arthrodesis for the treatment of advanced Kienböck disease. Sixteen patients with Lichtman stage IIIB Kienböck disease were treated with scaphotrapeziotrapezoid arthrodesis and lunate excision and were followed for a mean of 67 months (range, 49 to 108 mo). The indications for lunate excision included pain and limited motion associated with a collapsed lunate. Clinical evaluation included range of motion, grip strength, and modified Mayo wrist score. Based on plain radiographs, the carpal height ratio, ulnar carpal distance ratio, scaphoid translation ratio, and radioscaphoid angle were measured and any presence of degenerative changes was assessed. To investigate the effects of lunate excision on the radiologic results, we compared 12 patients with stage IIIB Kienböck disease who had only scaphotrapeziotrapezoid arthrodesis as the control group. Range of motion tended to be preserved, with a trend toward an increase in extension after surgery. Grip strength and modified Mayo score improved significantly. Fourteen patients with lunate excision demonstrated radiographic ulnar translation of the scaphoid beyond the scapholunate ridge, and radioscaphoid arthritis was observed in 4 patients. Compared to initial postoperative radiographs, the scaphoid translation ratio was significantly decreased, but neither ulnar carpal distance ratio nor radioscaphoid angle showed significant differences. In the control group, neither ulnar translation of the scaphoid nor significant changes of radiologic parameters was found between initial postoperative and final radiographs. Scaphotrapeziotrapezoid arthrodesis with lunate excision for advanced Kienböck disease provided favorable clinical results in terms of pain relief and functional improvement. With the absence of the lunate, however, the scaphoid had a tendency to shift toward the lunate fossa. This study suggests the risk of early development of radioscaphoid arthritis as a negative effect of lunate excision.