Methods of Immobilization after Achilles Tendon Rupture Repair: A Comparative Study in Rat Model

The Achilles tendon (AT) is the most frequently ruptured in the human body. Literature describing different immobilization methods' impact on tendon healing after AT repair is lacking. We compare plaster cast, splint, and K-wire to determine which is the most stable and has the fewest complications.Sixty rats aged 5-6 months were selected to establish Achilles tendon injury in two hind legs model. After suturing the ends of the AT together with a modified "Kessler" method (Prolene 5-0). The skin incision was interrupted and sutured with 1-0 thread. Rats were divided into three immobilization methods (plaster cast group, splint group, and K-wire group). In plaster cast group, the hind leg was cast with plaster in the extended position of the hip and knee joints, and the ankle joint was at 150°. Splint and K-wire group used splints and 0.8-mm K-wires, separately. The fixed period was 4 weeks. The incidence of stability and complications (death, necrosis of the legs, necrosis of the skin, and incisional infection) were recorded. Differences were detected using the chi-square test.Within 4 weeks observation, K-wires showed better stability (90%) compared with the other two ways (40% in plaster cast group, 65% in splint group; p < 0.05). Rats immobilized with K-wires (10%) suffered significantly lower complications compared with plaster cast and splint group (15%; p < 0.05).K-wire has better stability, lower complication rate than other methods. Immobilization with K-wire may be a promising tool in future clinical Achilles tendon rupture applications.