The effects of early mobilization in the healing of Achilles tendon repair

Twenty-four male New Zealand rabbits underwent suture repair of a tenotomy of the left achilles tendon, The rabbits were randomized into two groups of 12 animals; in group (A), the ankle was immobilized by pinning for 35 days, while in the group (B), the ankle was immobilized for only 14 days followed by active mobilization. Following sacrifice at 35 days postoperatively, the retrieved tendons were evaluated by biomechanical testing and histologic examination. Approximately 50% of stretching occurred in the first four days; average overall elongation was 9.5+/-1.0 mm and 12.7+/-1.5 mm (p=0.102) and average stiffness recovery was 67.4+/-2.0% and 82.9+/-1.9% (p=0.0004) for groups A and B respectively. Histologically both groups demonstrated traces of disorganized neo-collagen fibers at the repair site as early as the fourth day with subsequent appearance of more mature collagen. The results obtained from our study favor early mobilization of the repaired tendon, which seems to restore the functional properties of the tendons more rapidly than continuous immobilization of an identical surgical repair.