Instability of the scapholunate articulation from traumatic tears or degenerative attenuation of the interosseous ligament is associated with progressive collapse and degeneration of the wrist joint. Degenerative arthritis in such cases follows a consistent radiographic pattern that begins at the radioscaphoid articulation (1). The incidence of degenerative tears in the scapholunate interosseous ligament is unknown as radiographic changes appear late in the process. The aim of our study was to document the prevalence of age-related structural changes in the scapholunate interosseous ligament and attempt to establish a pattern of wear. We were also interested in studying the correlation, if any, between occupation and degenerative changes. To our knowledge changes in the scapholunate ligament with age have not been previously studied.

Twenty paired specimens were harvested for study from embalmed cadavers with an average age of 71.2 years. The specimens were examined by visual observation under magnification and findings were recorded with digital photographs. The three parts of the ligament as described by Berger et al were studied individually (2). The gross pathological changes were graded as perforation, attenuation or rupture to indicate increasing degree of severity of ligament wear. The data obtained was then correlated with sex, age and occupation of the donors.

Our results indicate that about 50% of wrists in the elderly demonstrate degenerative changes in the scapholunate interosseous ligament. The incidence increases with age rising to 80% after 70 years of age. The presence of articular surface wear is almost always associated with ligament degeneration. The type of occupation, manual or sedentary does not appear to have a bearing on the prevalence of degeneration in the ligament. Degenerative changes tend to start at the palmar portion of the scapholunate interosseous ligament and affect the dorsal part of the ligament least, correlating with previous biomechanical studies that suggest that the dorsal limb of the ligament is the strongest.

References

1. Watson HK. Ballet FL. The SLAC wrist: scapholunate advanced collapse pattern of degenerative arthritis. Journal of Hand Surgery - American Volume. 9(3):358-65, 1984.

2. Berger RA. The gross and histologic anatomy of the scapholunate interosseous ligament. Journal of Hand Surgery - American Volume. 21(2):170-8, 1996.