Skeletal troponin-I release in orthopedic and soft tissue injuries.

The skeletal isoform of troponin-I (sTnI) is a myofibrillar protein highly specific for myoskeletal injury. We used an indirect immunoenzymometric assay method with high analytical sensitivity to measure sTnI in patients with soft-tissue injury and in orthopedic patients. We assessed 20 soft-tissue injury patients and 16 orthopedic patients for sTnI, cardiac troponin-I (cTnI), creatine kinase (CK), myoglobin, and elastase within 24h of injury, in comparison with 17 control subjects. The mean (SD) ng/ml value for sTnI was higher in orthopedic patients (15.25 +/- 2.4) and in soft-tissue injury patients (10.41 +/- 1.8) than that in controls (2.5 +/- 0.9) P < 0.001, P < 0.05 respectively. Cardiac TnI was not detectable in any subjects (below the assay detectable limit of 0.3ng/ml). CK was significantly higher in orthopedic patients than in controls (P < 0.005) and myoglobin and elastase were not significantly changed in patients samples. The assay appeared to be suitable as a supplementary tool of reliability and relevance, for the study, identification, and diagnosis of skeletal muscle specific injuries in humans.