Rapid development of severe osteoarthritis associated with osteoid osteoma in a young girl.

In a 14-year-old girl with a 5 month history of left sided thigh pain, X-rays demonstrating osteoarthritis and a bone scintigraphy showing increased focal uptake in the femoral neck led to the diagnosis of an osteoid osteoma. The protuberant bone at the femoral neck was removed en-bloc and the diagnosis histologically confirmed. The synovium was extensively infiltrated with lymphocytes. Postoperatively the girl experienced neither the expected pain relief nor improvement of her hip function over the next 4 months. MRI and CT results indicated development of a severe osteoarthritis even though no residual lesion could be found.

A ganglion of the anterior horn of the medial meniscus invading the infrapatellar fat pad. Case report.

A case of ganglion of the medial meniscus that had invaded the infrapatellar fat pad is presented. Review of the literature embraces theories of pathogenesis, the effect on the surrounding tissue, the radiological techniques and the therapy.

Anti-inflammatory medication after muscle injury. A treatment resulting in short-term improvement but subsequent loss of muscle function.

We studied the effect of flurbiprofen, a non-steroidal anti-inflammatory drug, on muscles that had been subjected to exercise-induced injury. The muscles of the anterior compartment in the limbs of rabbits were cyclically activated as the ankle was simultaneously moved through passive plantar flexion every two seconds for thirty minutes. This treatment imposed acute passive lengthening (eccentric contractions) of the maximally contracted muscles of the anterior compartment. After the eccentric contraction-induced muscle injury, one group of rabbits was treated with oral administration of flurbiprofen, two times a day for six days, while the other group of rabbits served as untreated controls. The contractile, histological, and ultrastructural properties of the muscles were measured before the initial exercise and at three, seven, and twenty-eight days afterward. The group that was treated with flurbiprofen demonstrated a more complete functional recovery than the untreated controls at three and seven days but had a deficit in torque and force generation at twenty-eight days. The administration of flurbiprofen also resulted in a dramatic preservation of the intermediate filament protein desmin. After three days, the proportion of fibers of the extensor digitorum longus that lost desmin-staining was significantly greater in the untreated controls than in the treated animals (34 +/- 4.1 compared with 2.9 +/- 1.7 per cent) (p < 0.001), a finding that supports the concept of a short-term protective effect. However, the muscles in the treated animals still mounted a dramatic regenerative response, as indicated by the expression of embryonic myosin. Early in the recovery period (at three days), significantly fewer fibers of the extensor digitorum longus (2.2 +/- 1.4 per cent) expressed embryonic myosin in the treated animals than in the untreated controls (11.8 +/- 1.9 per cent) (p < 0.001). However, at seven days, the expression of embryonic myosin by the muscles from the treated animals (19.5 +/- 11.9 per cent) actually exceeded that of the muscles from the untreated controls (16.2 +/- 4.1 per cent). This finding suggests either a delayed or an ineffectual regenerative response by the muscles in the treated animals.

Contractile and cellular remodeling in rabbit skeletal muscle after cyclic eccentric contractions.

The time course of muscle contractile and cellular properties was studied in rabbit ankle flexor muscles after injury produced by eccentric exercise. Cyclic eccentric exercise was produced by increasing the tibiotarsal angle of the rabbit while activating the peroneal nerve by use of transcutaneous electrodes. Muscle properties were measured 1, 2, 3, 7, 14, and 28 days after exercise to define the time course of muscle changes after injury. A control group receiving only isometric contraction was used to study the effect of cyclic activation itself. The magnitude of the torque decline after 1 day was the same with use of isometric or eccentric exercise, but eccentric exercise resulted in a further decrease in torque after 2 days, at which time isometrically exercised muscles had fully recovered. The most prominent morphological changes in the injured muscle fibers were the loss of antibody staining for the desmin cytoskeletal protein and deposition of intracellular fibronectin, even when the injured muscle fibers retained their normal complement of contractile and enzymatic proteins. The presence of fibronectin inside the myofibers indicated a loss of cellular integrity. Invasion by inflammatory cells was apparent on the basis of localization of embryonic myosin. Thus eccentric exercise initiates a series of events that results in disruption of the cytoskeletal network and an inflammatory response that could be the mechanism for further deterioration of the contractile response.