Detection of muscle gap by L-BIA in muscle injuries: clinical prognosis

Hamstring injury is the single most common injury in professional football. MRI is commonly used to confirm the diagnosis and provide a prognosis of lay-off time. To evaluate the use of MRI as a prognostic tool for lay-off after hamstring injuries in professional football players and to study the association between MRI findings and injury circumstances. Prospective cohort study where 23 European professional teams, were followed between 2007 and 2011. Team medical staffs recorded individual player exposure and time-loss injuries. Radiological grading was performed using a modified Peetrons classification into four grades where grades 2 and 3 represent fibre disruption. In total, 516 hamstring injuries occurred and 58% of these were examined by MRI. Thirteen per cent were grade 0 injuries, 57% grade 1, 27% of grade 2 and 3% of grade 3. Grade 0 and 1 injuries accounted for 56% (2141/3830 days) of the total lay-off. The lay-off time differed between all four radiological grades of injury (8±3, 17±10, 22±11 and 73±60 days, p<0.0001). Eighty-three per cent of injuries affected the biceps femoris while 11% and 5% occurred to the semimembranosus and semitendinosus, respectively. Re-injuries (N=34/207) constituted 16% of injuries. All re-injuries occurred to the biceps femoris. MRI can be helpful in verifying the diagnosis of a hamstring injury and to prognosticate lay-off time. Radiological grading is associated with lay-off times after injury. Seventy per cent of hamstring injuries seen in professional football are of radiological grade 0 or 1, meaning no signs of fibre disruption on MRI, but still cause the majority of absence days.

Bioimpedance is the collective term that describes safe, non-invasive methods to measure the electrical responses to the introduction of a low-level, alternating current into a living organism, and the biophysical models to estimate body composition from bioelectrical measurements. Although bioimpedance techniques have been used for more than 100 years to monitor assorted biological components, the desire to translate bioelectrical measurements into physiological variables advanced the creation of empirical prediction models that produced inconsistent results. This paper succinctly reviews the origin, and critically evaluates the conceptual models and the implementation of bioimpedance in clinical research, including indirect assessment of assorted physiological functions and body composition (fluid volumes and fat-free mass), classification of hydration, regional fluid accumulation, prognosis in disease and wound healing. Despite widespread and mounting interest in the use of bioimpedance to characterise body structure and function, most experimental findings reveal the limitations of existing physical models and reliance on multiple regression models for use in assessments of an individual. Contemporary applications of bioimpedance emphasise the value of bioimpedance variables per se in some novel biomedical applications with the objective of identifying opportunities for future outcome-based research.

Physicians evaluating hamstring strains in professional football players are increasingly turning to magnetic resonance imaging to support the clinical diagnosis and management of the injury. However, little information is available to assess how magnetic resonance imaging compares with the clinical evaluation in establishing the duration of rehabilitation required. Magnetic resonance imaging of hamstring strains can be useful in determining duration of rehabilitation. Cohort study (Diagnosis); Level of evidence, 1. Fifty-eight professional football players with a diagnosis of hamstring injury made by the team physician were enrolled in the study. All players underwent magnetic resonance imaging and a clinical evaluation by an independent physical therapist within 3 days of the injury. Presence, type, and location of injury were recorded in each examination. The physical therapist estimated the time required until return to competition, and the radiologist used the length of the injury (coronal view) to establish rehabilitation duration. Both clinicians were blinded to the other modality. Clinical and magnetic resonance imaging assessments were in agreement in 38 of 58 cases (65.5%). In 18 cases (31.0%), a clinically positive diagnosis was made, but no abnormalities were evident on magnetic resonance imaging. In 2 cases (3.4%), magnetic resonance imaging detected an injury, whereas the clinical examination had negative or equivocal findings. Both clinical examination and magnetic resonance imaging findings were strongly correlated with the actual time required to return to competition (r = .69, P < .001 and r = .58, P < .001, respectively). The correlation coefficient between clinical predictions and magnetic resonance imaging findings was moderate (r = .36, P = .006). This study shows that magnetic resonance imaging is not required for estimating the duration of rehabilitation of an acute minor or moderate hamstring injury in professional football players.