Effect of immobilization, immediate mobilization, and delayed mobilization on the resistance to digital flexion using a tendon injury model.

This study employed a tendon injury model in chickens to determine the effect of immobilization, immediate mobilization, and delayed mobilization on the energy required to fully flex the digit following surgical trauma to the tendon, as determined by measurement of the work of flexion (WOF). The immobilized group showed no increased WOF at 3 days compared to the zero time control values, followed by significant increased WOF at 1 week (36%), 2 weeks (41%), and 3 weeks (63%). The immediate mobilization tendons showed an initial 36% rise in the work of flexion at 3 days, which increased to 40% at 1 week, and then decreased to baseline control values by 3 weeks. Delaying the period of mobilization until 5 days was not shown to significantly lower the peak WOF value at 1 week, but delaying the period of mobilization until 3 days lowered the peak WOF value at 1 week dramatically to 13%; both the 3- and 5-day delayed-mobilization groups returned to baseline WOF values by 3 weeks. From these data, it can be assumed that there is an early increase in the work necessary for flexion of the injured operated digit and tendon that is present in the immediately mobilized tendons at 3 days and persists to 1 week and that does not appear until 1 week in the immobilized tendons; this rise in WOF can be blunted by delaying the institution of mobilization.