Thigh muscle atrophy after femoral shortening. Vastus intermedius cross-section studied in osteotomized rats.
We determined the effect of a shortening/lengthening osteotomy on muscle fiber cross-sectional area in the vastus intermedius in 14 rats. The left femur was shortened 5 mm in half of the rats and elongated 5 mm in the other half. In both groups, the right femur was osteotomized and stabilized without shortening/lengthening. After 3 months, open biopsy specimens of the vastus intermedius were taken for measurements of the muscle cross-sectional area in both Type 1 and Type 2 fibers; 150 fibers were measured in each specimen. In the shortened group, the cross-section was reduced in both types of fibers. After lengthening, no differences in the fiber cross-sectional area were found. We conclude that differences in stretch and tension of the muscles are responsible for the atrophy after femoral shortening and the maintenance of the fiber cross-sectional area after lengthening.
Leivseth
G
G
Department of Orthopedics, Tromsø University Hospital, Norway.
Reikerås
O
O
D000818:Animals; D001852:Bone Lengthening; D003430:Cross-Sectional Studies; D005269:Femur / Q000473:pathology / Q000601:surgery*; D008297:Male; D009133:Muscular Atrophy / Q000209:etiology* / Q000473:pathology; D010027:Osteotomy / Q000009:adverse effects* / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains; D013848:Thigh