Background: Scapholunate advanced collapse wrist deformity is a common pattern of degenerative arthrosis of the wrist. This study prospectively evaluated a series of patients who underwent four-corner fusion using a circular plate internal fixation technique.
Methods: Patients with symptomatic stage II scapholunate advanced collapse wrist deformity were treated with scaphoid excision and four-corner fusion using the Spider Limited Wrist Fusion Plate (KMI, San Diego, Calif.). Patients were prospectively evaluated at 6 months and 1 year using a standard study protocol with radiographs, functional tests, and an outcomes questionnaire. Outcomes were compared with those of historical series from the literature.
Results: Eleven patients were enrolled and 10 patients completed their 1-year follow-up. Grip strength, lateral pinch strength, and Jebsen-Taylor test scores at 1 year were not significantly different from preoperative values. Mean active range of motion was 87 degrees preoperatively and 74 degrees at 1-year follow-up (p = 0.19). The Michigan Hand Outcomes Questionnaire showed no significant improvement in function, activities of daily living, work, pain, or patient satisfaction. The mean pain scores decreased from 54 preoperatively to 42 1-year postoperatively (p = 0.30), indicating persistent wrist discomfort. Three patients had broken screws: one was asymptomatic, one required 3 months of strict wrist immobilization, and one was reoperated for symptomatic nonunion.
Conclusions: Four-corner fusion using the first-generation Spider plate technique has the advantage of earlier mobility and more patient comfort from absence of protruding Kirschner wires; however, patients continued to have disabling pain, functional limitations, work impairment, and low satisfaction scores postoperatively. Although limited by a small patient sample, this series presents outcomes data that may be useful in counseling patients who are contemplating four-corner fusion using this internal fixation device. Further investigation is necessary to evaluate the biomechanical properties of the Spider plate. The data suggest that better implants should be designed to avoid implant failure, which occurred in three of the 11 patients in this series.