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Soft-tissue chondromas are rare and benign soft-tissue tumors. Over 95% occur in the hands and feet. They are seen in both sexes equally and mainly occur in patients aged 30-60 years. If excised fully, they do not reoccur, and no cases in the literature have reported malignant transformations. [ABSTRACT FROM AUTHOR]

A 49-year-old white man presented for evaluation of an enlarging left distal thigh mass with increasing pain over the last several months. The mass was first noticed 11 years prior to this presentation. During his initial examination, the patient was diagnosed with myositis ossificans and had a partial resection of the mass to improve knee function. His current examination revealed a low grade parosteal osteosarcoma arising from pre-existing mature heterotopic ossification. To our knowledge, no reported cases of secondary parosteal osteosarcoma arising from myositis ossificans have been reported in the literature; only a few reports of malignant transformation of myositis ossificans were found.

The purpose of this project was to study the efficacy of quantitative muscle hardness (QH) curve analysis for noninvasive measurement of muscle compartment interstitial pressure (IMP), and to eliminate the need for a comparison normal QH measurement to determine a pathologic reading. Elevation of IMP may lead to limb compartment syndrome, which may result in irreversible dysfunction, chronic pain and contracture. Two studies were performed by two separate independent examiners on male volunteers, where IMP measurements and QH curves were obtained. QH curves were divided into three parts comparing the third part to the second part using the coefficient of determination (R(2)). In 205 limb compartments, there were 1432 comparison readings of the IMP versus R(2). Using receiver operator characteristic curve analysis for all data from both studies, an R(2) cutoff of 0.974 best corresponded to a pathologic IMP of 50 mmHg. For both sets of data and for each compartment tested, the mean IMP values were statistically different (t-test: P < 0.0001) for the group with R(2) values less than 0.974 compared to the group of R(2) values greater than or equal to 0.974. In addition, a pressure prediction model was formulated with a strong overall correlation coefficient of 0.78. The data of this study support that QH analysis is potentially useful for the monitoring of IMP elevation in compartment syndrome.

Allograft bone is the primary source of graft material for large skeletal defects. No study has determined the physical characteristics of such grafts after various periods of time in vivo for incorporation and remodeling. The purpose of this pilot study was to obtain allograft tissue and biomechanically evaluate the tissue to assess allograft bone material properties. The mechanical properties of the retrieved allograft tissue were compared to allograft bone prior to transplantation. Histological analysis of the retrieved allograft tissue is currently underway to correlate degree of incorporation, allograft porosity, and microfracture density with allograft material properties. After allograft retrieval, radiographs were used to plan sectioning for histological and biomechanical analyses. Rectangular sections of uniform dimensions (50 x 3 x 3 mm) were mapped and machined from the bulk specimens. The samples were loaded in bending in the medial to lateral direction using a 4-point bending fixture to obtain flexural elastic modulus and breaking strength. Preconditioning was applied to each specimen by cycling through 5 submaximal loading cycles (maximum deflection = 1% specimen length). After preconditioning, the specimens were loaded to failure at a rate of 1 mm/min. Retrieved specimens consisted of 1 tibia, 2 femurs, and 2 humeri ranging from 2 to 13 years in vivo. Two control tibia specimens were also tested. Assuming that material properties of cortical bone are consistent regardless of skeletal site, the preliminary data indicates that allograft modulus and strength decline with time in vivo. Testing and analysis of more specimens continue in order to corroborate these initial results.