Limb salvage surgery using a tumor prosthesis for the treatment of malignant bone tumors in the proximal femur is an effective method for preserving hip joint function. On the other hand, maintaining hip joint stability can be challenging because of the extensive resection of the bone and surrounding soft tissue. This paper reports an unusual case of hip dislocation in a patient with a proximal femoral osteosarcoma who underwent limb salvage surgery. Over six years, the tumor prosthesis gradually migrated posterosuperiorly above the iliac crest, resulting in 14 cm of lower limb shortening. The acetabular reconstruction was performed using an allograft, and the middle segment of the tumor prosthesis was removed to allow for hip reduction. Concurrent reconstruction of the hip abductor muscles was also carried out. No recurrence of the dislocation was observed during follow-up, and the patient could walk independently with the aid of an orthopedic brace, despite an 8 cm leg length discrepancy.

There are approximately 20 known species of the genus Cryptosporidium, and among these, 8 infect immunocompetent or immunocompromised humans. C. hominis and C. parvum most commonly infect humans. Differentiating between them is important for evaluating potential sources of infection. We report here the development of a simple and accurate real-time PCR-based restriction fragment length polymorphism (RFLP) method to distinguish between C. parvum and C. hominis. Using the CP2 gene as the target, we found that both Cryptosporidium species yielded 224 bp products. In the subsequent RFLP method using TaqI, 2 bands (99 and 125 bp) specific to C. hominis were detected. Using this method, we detected C. hominis infection in 1 of 21 patients with diarrhea, suggesting that this method could facilitate the detection of C. hominis infections.
Child ; Cryptosporidiosis/*diagnosis/*parasitology ; Cryptosporidium/*classification/*genetics ; Female ; Genotype ; Humans ; Polymerase Chain Reaction/methods ; Polymorphism, Restriction Fragment Length ; Sensitivity and Specificity