Dramatic loss of human muscle fibre size after leg fracture and immobilization in plaster casts

Initiated and written by Professor Anthony J Sargeant while working at the Joint Services Medical Rehabilitation Centre at Chessington, Surrey, UK this was the first research paper in the scientific literature that showed the massive loss in muscle fibre size in otherwise healthy young male patients who following leg fracture had been immobilized in plaster casts. Although gross measurement of leg muscle size suggested a modest loss of about 12% after an average of 6 weeks in plaster cast needle biopsy of the vastus lateralis muscle revealed a reduction in cross sectional area of muscle fibres of nearly 50%. Furthermore recovery appeared very slow and many subjects seemed never to fully recover in terms of muscle fibre size and strength – deficits being identified in later studies many years later after the injury.
Clinical Science and Molecular Medicine
Clin Sci Mol Med. 1977 Apr;52(4):337-42

1. Seven patients who had suffered unilateral leg fracture were studied after removal of immobilizing plaster casts. 2.

Leg volume measured anthropometrically was reduced by 12% in the injured leg (5-68 +/- 1-05 litres) compared with the uninjured (6-43 +/- 0-87 litres). Associated with this loss was a similar reduction in the net maximum oxygen uptake achieved in one-leg cycling, from 1-89 +/- 0-21 1/min in the uninjured leg to 1-57 +/- 0-18 1/min in the injured. 3. Measured by a percutaneous needle biopsy technique, a reduction of 42% was found in the cross-sectional area of the muscle fibres sampled from the vastus lateralis of the injured compared with the uninjured leg. 4. Staining for myosin adenosine triphosphatase activity showed that both type I and II fibres were affected, being reduced respectively from 3410 to 1840 micronm2 and from 3810 to 2390 micronm2 cross-sectional area. 5. Possible reasons and implications are discussed for the discrepancy between the magnitude of the difference observed in the gross measurement of leg function (maximum oxygen uptake) and structure (leg volume) as compared with the cellular level (cross-sectional fibre area).



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