Comparison of surgically attached and non-attached repair of the rat Achilles tendon-bone interface. Cellular organization and type X collagen expression.
The effects of surgical repair versus non-repair on cell morphology and type X collagen expression were investigated using a rat model of Achilles tendon avulsion. The animals were divided into four groups. In Group 1, tendon was reattached to the original attachment site by suturing through a drill hole in the calcaneus; in Group II, tendon was not reattached and a drill hole was not made; in Group III, tendon was not reattached but a drill hole was made; and the animals in Group IV were sham operated. In Group I (tendon reattached), at 2 weeks postoperatively, many hypertrophic chondrocytes appeared at the reattachment site adjacent to bone and type X collagen was detected immunologically both in the cells and in the extracellular matrix. After 4 weeks, the cells at the original site of attachment were arranged in rows along the newly formed tendon fibers and were stained with type X collagen antibody. By contrast, when tendon was not reattached (Groups II and III), a gap between the original attachment site and the tendon stump was observed through the entire postoperative period. At 8 weeks, the original attachment site was covered by fibrocartilaginous tissue and tendon became attached to the calcaneal fibrocartilage area, which is proximal to the original attachment site. Type X collagen was detected in the cells which were adjacent to bone. In Group IV (sham operation), there were no changes in histology or type X collagen distribution, either at the attachment site or in tendon and bone, compared with the non-operated control rats. These results suggest that surgical reattachment of tendon to the original site is important to help reorganize cells during the repair process. Type X collagen was identified immunohistochemically in the cells adjacent to bone in all the groups, suggesting that it may play a role in maintaining distinct areas of calcified and non-calcified fibrocartilage.
Fujioka
H
H
Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville 22908, USA.
Thakur
R
R
Wang
G J
GJ
Mizuno
K
K
Balian
G
G
Hurwitz
S R
SR
D000125:Achilles Tendon / Q000378:metabolism* / Q000601:surgery*; D000818:Animals; D001842:Bone and Bones / Q000601:surgery*; D003094:Collagen / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley
D003094:Collagen