Collagen and Vascular Changes in the Scapholunate Ligament Following Injury: An Immunohistochemical Study

The scapholunate ligament (SLL) is the most frequently injured wrist ligament. The aim of this study was to investigate cellular and extracellular changes within the SLL following injury.

Fifteen SLLs were harvested, ranging between 39 days to 20 years from time of injury. These specimens were subject to immunohistochemical analysis to characterize their vascular and collagen constitution.

Of the 15 ligaments, 4 were harvested <3 months from injury, and 11 harvested >3 months from injury. The mean type I collagen density was 45.6% (25.2% to 55.9%) in all specimens. The mean type III collagen density was 47% (38.2% to 51.8%) of the ligament area in specimens <3 months after injury and 30.6% (13.3% to 44.1%) in those >3 months after injury. Type III collagen density was highest in the volar subunit. Type I collagen decreased only minimally in specimens taken within 2 years of injury. The increase in the type I:III collagen ratio reflected the decline in type III collagen. Blood vessels were found in 13 of 15 specimens. Mean vessel density for all specimens was 1.3% (0% to 7.1%), with the highest density of 1.8% (0% to 10%) in the volar subunit. The vessel density decreased from 2.9% (1.3% to 4.3%) to 1.6% (0% to 10%) in the volar subunit in specimens harvested >3 months after injury.

Mean type III collagen density decreased with time, most notably within the volar subunit. Mean type I collagen density held comparatively stable in ligaments taken within 2 years from injury. Blood vessels were detected in 87% of specimens, with the highest density in the volar subunit.

The SLL displays a collagen profile similar to other ligaments with favorable healing capacity. The volar subunit possessed a collagen ratio and vessel density that may suggest its acute repair and inclusion in reconstructive techniques has merit.