Identification of cutaneous functional units related to burn scar contracture development

The development of burn scar contractures is due in part to the replacement of naturally pliable skin with an inadequate quantity and quality of extensible scar tissue. Predilected skin surface areas associated with limb range of motion (ROM) have a tendency to develop burn scar contractures that prevent full joint ROM leading to deformity, impairment, and disability. Previous study has documented forearm skin movement associated with wrist extension. The purpose of this study was to expand the identification of skin movement associated with ROM to all joint surface areas that have a tendency to develop burn scar contractures. Twenty male subjects without burns had anthropometric measurements recorded and skin marks placed on their torsos and dominant extremities. Each subject performed ranges of motion of nine common burn scar contracture sites with the markers photographed at the beginning and end of motion. The area of skin movement associated with joint ROM was recorded, normalized, and quantified as a percentage of total area. On average, subjects recruited 83% of available skin from a prescribed area to complete movement across all joints of interest (range, 18-100%). Recruitment of skin during wrist flexion demonstrated the greatest amount of variability between subjects, whereas recruitment of skin during knee extension demonstrated the most consistency. No association of skin movement was found related to percent body fat or body mass index. Skin recruitment was positively correlated with joint ROM. Fields of skin associated with normal ROM were identified and subsequently labeled as cutaneous functional units. The amount of skin involved in joint movement extended far beyond the immediate proximity of the joint skin creases themselves. This information may impact the design of rehabilitation programs for patients with severe burns.