Effects of hydroxyapatite and alumina sheaths on postoperative peritendinous adhesions in chickens

Abstract

Two experimental methods for restoring flexor tendon sheath integrity and preventing adhesions around traumatized flexor tendons utilizing artificial tendon sheaths made of either hydroxyapatite (HAp) or alumina were studied in a flexor tendon-trauma model and compared to a standard tendon sheath repair and a control. Eighty toes were divided equally into a control group, a sheath repair group, an HAp group, and an alumina group. Profundus tendons in zone II were divided and repaired after sublimis excision in all groups. In the sheath repair group, the flexor sheath was also repaired after suturing the tendon. In artificial sheath groups, sheaths made of HAp and alumina were placed over the repair sites to protect them from the surrounding tissues. In the control group, after repairing the tendon, the flexor sheath was excised and no artificial sheaths were used. Each toe was immobilized in a plaster cast for 3 weeks. After three weeks, the plaster cast was removed followed by the removal of the sheaths in the artificial sheath groups through a small incision in the skin in zone II. Active mobilization was encouraged in each group. Postoperative adhesions were examined at 3, 6, 9, and 12 week intervals by using light microscopic techniques. To further explore the effects of artificial sheaths on tendon healing, transmission electron microscopy was done for the HAp and alumina groups at 3, 6, and 12 week intervals. Results demonstrated decreased severity of postoperative adhesions in the HAp as well as in the alumina groups in comparison with the sheath repair and controls. A space resembling the fibro-osseous canal was formed around the tendon after removing the sheaths. This space remained patent until 12 weeks, 9 weeks after removing the sheaths, and a newly formed tendon sheath-like structure lined by synovial cells and with a peritenon-like structure over the tendon surface was observed. In the sheath repair and control groups, the severity of adhesions was decreased with the passage of time, to some extent due to unrestricted mobility. However, a newly formed tendon sheath or peritenon-like structure was not observed. Electron microscopic studies confirmed good healing at the suture in the HAp and alumina groups with no evidence of necrosis. These results are qualitative in nature as no statistical tests were performed. From these results we conclude that if the tendon is separated from the surrounding granulation tissue by a barrier with good biocompatibility, the tendon can heal with fewer adhesions.(ABSTRACT TRUNCATED AT 400 WORDS)

A new material for prevention of peritendinous fibrotic adhesions after tendon repair: oxidised regenerated cellulose (Interceed), an absorbable adhesion barrier

“…In two studies repaired tendons with enlarged sheath tunnel had greater tendon movement than those within a narrowed sheath [22]. At other times surgical repair of the sheath is not possible because of major defects in its substance after injury or the sheath is crushed so badly that it must be resected [20]. In such cases attempts are made to restore the integrity of the sheath or to replace it with various biological or synthetic materials [11].…”

“…The idea of a mechanical barrier to adhesion formation is not new. In previous decades, many different materials, both biological and synthetic, have been tested [3,6,11,16,19,20,25]. Biological barriers have met with variable success and add donor site morbidity and surgical complexity to the procedure.…”

“…It is believed that sutures, tendon sheath damage and immobilisation all contribute to the adhesion formation [9]. The subcutaneous tissue and the skin act as a single compartment during the healing process, and adhesion around the repair site interferes with tendon gliding, which results in contracture and decreased range of motion of the digit [20]. The control of excessive scar formation is essential to restore the functional integrity of a healing tendon after surgery.…”

“…Mechanical barriers like alumina sheaths, polyethylene membranes, cellophane, sterispon wrapping, stainless steel or silicone sheeting, amniotic membranes, chitosan membranes, silicone rubber envelopes, polytetrafluoroethylene surgical membranes, seprafilm, hydrogel sealant, chondritin sulphate coated polyhydroxyethyl metacrylate membrane, and autogenous vein graft may be either biological or synthetic [3,6,11,16,19,20,25]. The ideal barrier would be easy to use, biocompatible, allow tendon movement, not add undue bulk, remain at the site of repair long enough to allow tendon healing (extrinsic healing), absorbable, and cheap.…”

“…Il n'y a pas eu d'infection. Macroscopiquement, dans le groupe I, 3 tendons (13.1%) n'ont pas présenté d'adhérence péri-tendineuse et 20 …”