Novel approaches to the assessment and strategic modification of flexor tendon adhesion formation

Mobilisation of injured tendons results in improved tendon healing and reduced adhesions. The precise mechanism for the effect on adhesions is unknown. This thesis presents the development of a series of techniques to examine the hypotheses: that mobilisation exerts its favourable effects by modifying local strain responses to applied stress by altering cell attachment to the extracellular matrix; that selectively blocking cell-matrix attachment can mimic these effects. Attachment of tendon-synovial complex cells and mobilised and immobilised adhesion cells to collagen and fibronectin was examined in vitro. Attachment of intrinsic cells and mobilised adhesion cells was higher than that of extrinsic cells and immobilised adhesion cells. These data suggest that mobilisation favours intrinsic cell attachment to the matrix and their contribution to healing. An in vivo model system was developed in the injured flexor tendon-synovial complex, enabling quantitative hierarchical mechanical assessment of mobilised and immobilised adhesions. Three-fold higher local strain values and increased heterogeneity of local strain values were seen in mobilised adhesions. Mobilisation may result in localised mechanical failure due to altered local strain patterns. A novel biomaterial was investigated in vitro and in vivo. Reduction in restrictive adhesion parameters was observed, with an associated decrease in adhesion cellularity without compromising tendon cellularity. Inhibition of fibroblast attachment resulted in a mimicking of the effects of mobilisation