Analysis of carpal malalignment caused by scaphoid nonunion and evaluation of corrective bone graft on carpal alignment

Abstract

Purpose: To clarify the correlation between a scaphoid deformity and carpal malalignment in patients with scaphoid waist nonunion and to investigate how accurately a corrective bone graft improves carpal malalignment according to the preoperative plan.

Methods: A total of 38 patients were analyzed retrospectively. Surgery was performed according to the anterior wedge bone graft method described by Fernandez. The scaphoid deformity and carpal malalignment were evaluated by the changes in the intrascaphoid angle (ISA) and axial length (AL) and by the changes in the radiolunate angle (RLA) and scapholunate angle (SLA), respectively, compared with the uninjured side by using standardized x-rays. Each variable was measured at 1 year after surgery. By performing multiple regression analysis, the correlation between the scaphoid deformity and carpal malalignment and between the correction of the scaphoid deformity and the change in carpal alignment were analyzed.

Results: Compared with the uninjured side, the mean respective changes in the ISA, AL, RLA, and SLA were 11°, -1.3 mm, 14°, and 11°, preoperatively. The changes in the RLA and SLA correlated with the change in the ISA, but not with the change in the AL. The mean postoperative corrections of the ISA and AL were 15° from full extension and 1.7 mm, and the changes in the RLA and SLA were 18° and 12° from full extension, respectively. The change in the RLA correlated with the corrections of the ISA and AL. Although the change in the SLA did not correlate with either of them, the mean postoperative SLA was not significantly different from the mean value of the uninjured side.

Conclusions: The degree of humpback deformity of the scaphoid correlated with the degree of carpal malalignment. The corrective bone graft resulted in the expected recovery of carpal alignment according to the preoperative plan.

Type of study/level of evidence: Prognostic IV.