Heterotopic ossification is defined as the presence of lamellar bone at locations where bone normally does not exist. The condition must be distinguished from metastatic calcifications, which mainly occur in hypercalcaemia, and dystrophic calcifications in tumours. It is a frequent complication following central nervous system disorders (brain injuries, tumours, encephalitis, spinal cord lesions), multiple injuries, hip surgery and burns. In addition to this acquired form, hereditary causes also exist, such as fibrodysplasia ossificans progressiva, progressive osseous heteroplasia and Albright's hereditary osteodystrophy. Although these conditions are extremely rare, they can provide useful information on the physiopathology of heterotopic ossification, and thus lead to novel and causal treatment modalities. Heterotopic ossification is no trivial complication. A limitation of the range of joint motion may have serious consequences for the daily functioning of people who are already severely incapacitated because of their original lesion. Increased contractures and spasticity, pressure ulcers and increasing pain further compromise the patient's capabilities. Consequently, we feel that attention should be paid to the pathogenesis and particularly the prevention and treatment of this disorder.

This systematic review provides preliminary evidence for the association between impaired core stability and the development of lower extremity injuries in healthy athletes. Deficits in various aspects of core stability were identified as potential risk factors for lower extremity injuries. As such, core stability needs to be considered when screening athletes.

This prospective study identified both female sex and the diminished blood flow response after running as significant risk factors for the development of Achilles tendinopathy. UTC of tendon structure, Achilles tendon thickness, and foot posture did not significantly contribute to the prediction of Achilles tendinopathy. A general evaluation of tendon structure by UTC, measurement of tendon thickness, or determination of the foot posture index will not allow clinicians to identify patients at risk for developing Achilles tendinopathy. Furthermore, it may be possible to improve blood flow after activity by using noninvasive techniques (such as prostaglandins, compression stockings, heat, massage, and vibration techniques). These techniques may be useful in the prevention and management of Achilles tendinopathy, but further research is needed.

Lipoma arborescens is a rare cause of chronic monoarticular arthritis, with only a few cases reported in the literature. It is most commonly seen in the knee, but cases in other joints such as the wrist, shoulder, and elbow have also been described. It is a benign condition, in which the subsynovial tissue is replaced diffusely by mature fat cells. We describe a case involving the knee and discuss the symptoms, diagnosis, and treatment.

Hamstring injuries have not been under research in physical education teacher education (PETE) students so far. Within the frame of the development of an injury prevention program, for this study we conducted an analysis of modifiable risk factors for hamstring injuries in PETE students. Hamstring injuries of 102 freshmen bachelor PETE students were registered prospectively during one academic year. Eighty-one students completed maximum muscle strength tests of hip extensors, hamstrings, quadriceps (isometric) and hamstrings (eccentric) at the start of the academic year. Sixty-nine of the latter completed a single leg hop for distance (SLHD). Risk factors for hamstring injuries were statistically detected using logistic regression. Sixteen hamstring injuries (0.16 injuries/student/academic year; 0.46 injuries/1000 h) occurred to 10 participants. Eight cases were included in the risk factor analysis. Lower eccentric hamstring strength (odds ratio (ODD) = 0.977; p = 0.043), higher isometric/eccentric hamstring strength ratio (ODD = 970.500; p = 0.019) and lower score on the SLHD (ODD = 0.884; p = 0.005) were significant risk factors for hamstring injury. A combination of eccentric hamstring strength test and SLHD could give a good risk analysis of hamstring injuries in PETE students. This might offer great perspectives for easily applicable screening in a clinical setting.