Stage III Advanced Wrist Collapse Treatment Options: A Cadaveric Study

Abstract

Altered wrist biomechanics consequent to a scapholunate dis-sociation or a scaphoid nonunion accelerates the degeneration of the surrounding articular surfaces and often induces arthritic progression referred to as a scapholunate advanced collapse (SLAC) or scaphoid nonunion advanced collapse (SNAC). 1,2 Watson and Ballet described four stages of the arthritic progres-sion of the affected articulations. 2 Stage III progression is deter-mined by radiological evidence of degenerative changes to both the radioscaphoid and the lunate-capitate joint surfaces, and is generally associated with progressive pain and reduced wrist Keywords ► scaphoid nonunion advanced collapse ► arthritis ► advanced collapse ► biomechanics ► wrist Abstract Background Scapholunate advanced collapse and scaphoid nonunion advanced collapse result in high morbidity and pose significant challenges for active patients. Multiple treatment options have been proposed to yield satisfactory results; however, restoration of physiological wrist motion remains an issue. Questions/Purposes The objective of this study was to compare wrist mobility after four different treatment methods for grade III wrist collapse: (1) no treatment, (2) scaphoidectomy and lunate-capitate arthrodesis, (3) scaphoidectomy, lunate-capitate arthrodesis, and triquetrum-hamate arthrodesis, and (4) scaphoidectomy, lunate-capitate arthrodesis, and triquetrum excision. Methods Four paired (n ¼ 8) fresh-frozen human cadaveric upper limbs were used in this controlled laboratory study. Computed tomography scans were collected at all testing states and measurements were made to evaluate midcarpal joint mobility and alignment. Results A significant decrease in wrist extension was observed for all treatments. Middle column and two-column arthrodesis demonstrated no significant differences for carpal alignment and mobility. No significant differences were observed for triquetrum-hamate mobility or wrist extension between the partial and two-column arthrodesis. Triquetrum excision significantly improved ulnar deviation. Conclusion The most important finding of this study was that the one-column arthrodesis has comparable carpal alignment and range of motion to that of bi-column arthrodesis. Clinical Relevance The results of this study suggest that a stage III advanced wrist collapse can be treated by isolated lunate-capitate arthrodesis with scaphoidectomy. Fusion between the remaining carpal bones may not be necessary because the carpal alignment and range of motion of the remaining joints were not significantly different in the present study.