|
Year |
2002 |
|---|---|
|
Question Number |
24. |
|
Category |
Orthopaedic Science |
Question
Healing after complete midsubstance laceration of skeletal muscle in an adult is characterized by
1- Hypertrophy of the distal muscle.
2- Dense connective tissue scar.
3- Complete functional recovery.
4- Denervation of the proximal muscle portion.
5- Proximal muscle atrophy.
Figures
Answer (click for answer)
Preferred Response: 2
The articles cited are histological studies of a rabbit and mouse model for muscle regeneration and repair following an experimentally created muscle laceration injury. Both studies demonstrated that complete functional recovery was not seen in either model. In the rabbit model, completely lacerated extensor digitorum longus muscles were shown to regain only 50% of their ability to produce tension versus 60% in partially lacerated muscle bellies.
Histological specimens of the distal segment of the lacerated rabbit muscles demonstrated fiber atrophy, increased fibrosis, and other changes suggestive of denervation. In both studies dense fibrous scar tissue was seen separating the two segments. Menetrey et al demonstrated that suturing the lacerated gastrocnemius muscle in mice prevented formation of deep scar tissue. They recommended a modified Kessler stitch be used to suture the laceration to achieve the best morphologic and functional healing.
Reference: Mentery J, Kasemkijwattana C, Fu FH, et al. Suturing versus immobilization of a muscle laceration: A morphological and functional study in a mouse model. Am J Sports Med 199;27:222-229.
Garret WE Jr, Seaber AV, Boswick J, et al. Recovery of skeletal muscle after laceration and repair. J Hand Surg Am 1984;9:683-692.