Progressing arthrosis and a high conversion rate 11 (4-19) years after four corner fusion

Four corner fusion (4CF) is a limited wrist arthrodesis offered to patients with painful wrists due to scaphoid non-union advanced collapse (SNAC) or scapho-lunate advanced collapse (SLAC). A retrospective study of 42 wrists (in 36 patients), operated with 4CF using K-wires and autologous bone graft followed up after 11 (4-19) years was performed, 25 were male and mean age at surgery was 51 (22-71) years. During the follow-up period, 13 wrists were converted to total wrist arthrodesis or wrist arthroplasty, and one is scheduled for conversion (14/42, 33%) due to non-union (3), DISI and progressing arthrosis (7) or progressing arthrosis (4). Non-union was seen in 3/42 (93%) wrists, all were later converted. At the final follow-up, the patients reported residual pain, VAS = 15 and 36 at rest and activity, respectively, and QDASH/PRWHE = 32 and 31, respectively. Active range of motion (AROM) was 38% and grip-strength was 76% compared to the uninjured side. Degenerative changes were seen in 88% on CT scans at follow-up. 4CF renders an acceptable pain reduction and function in the majority of patients, but increased degeneration and a high number of conversions after a longer follow-up time is concerning.