Horizontal Screws Placement for Four-corner Arthrodesis in Advanced Wrist Osteoarthritis : A Consecutive Case Series

Four-corner arthrodesis with scaphoid excision has been shown to be an acceptable method for treating wrist degenerative changes, by fusing the lunate, capitate, hamate, and triquetrum bones. The procedure involves removing the scaphoid bone and stabilizing the remaining four bones in a fixed position using screws or other fixation devices. The screw configuration for four-corner arthrodesis typically involves strategic placement to ensure stability and proper fusion of the carpal bones. However, there is no universally agreed-upon screw configuration for four-corner arthrodesis. This study examined a consecutive case series with defined horizontal screws placement technique for outcome and complications.

A retrospective assessment was performed in a consecutive cohort of 8 patients, mean age 52 (range, 32-70) years, who underwent a standardized 4-corner arthrodesis with horizontal screws placement for a diagnosis of stage 2 and stage 3 of scapholunate advanced collapse (SLAC) for 2 cases and scaphoid nonunion advanced collapse (SNAC) for 8 cases. After scaphoid excision and removal of cartilage and subchondral bone in the midcarpal joint through a limited arthrotomy, capitolunate fixation was achieved with a cannulated headless compression screw. Afterthat, triquetrohamate and capitohamate fixation were done with single cannulated headless compression screw. Scaphoid was used as a bone graft. Complete data were obtained for all 8 of the patients. Follow-up radiographic outcomes included time to union, union rate, carpal height ratio, joint space height ratio, arthritic change and complications.

Average follow-up was 117.875 days (n = 8; range 33-196 days). The mean time to union was 40.63 days (n=8; range 20-61 days). Union occurred in all 8 wrists (100%). Radiographs demonstrated union of the primary capitolunate, capitohamate and triquetrum-hamate fusion mass in all of the cases. After arthrodesis was achieved, the mean carpal height ratio, measured according to Youm et al's method, was significantly improved with mean difference 0.04 (0.02 to 0.05, P<0.001). There was no significant difference in the mean joint space height ratio, measure according to Bear et al’s method between preoperative and postoperative measurements with mean difference -0.001 (-0.02 to 0.02, P=0.904). There were no cases of asymptomatic loss of radiolunate joint space. In terms of hardware, there was symptomatic screw prominent (of 1 screw) that need removal in 1 case. No patients underwent reoperation. There was 1 case develop extensor carpi ulnaris tendinitis that resolved with oral medications. At the final follow up ,there were no cases of capitolunate, capitohamate, triquetrohamate and radiolunate joint arthritis.

The screw configuration for four-corner arthrodesis is crucial for achieving stable fusion and optimal outcomes. These radiographic results of horizontal screws placement for four-corner arthrodesis were comparable to the results of previously published techniques in terms of time to union and fusion rates. The technique exploits the theoretical advantages of strong compression between midcarpal joint as well intercarpal joint.

Keywords: Wrist osteoarthritis, horizontal screws, four-corner, arthrodesis, capitolunate