Koichi Kai

Avulsion of the hamstring muscles from the ischial tuberosity: a report of two cases

In two rare cases with avulsion of the hamstring muscles from the ischial tuberosity without fracture of the ischium, the clinical features were: (1) sudden onset of pain in the buttock; (2) difficulty on standing after trauma; (3) a palpable defect and tenderness on the area distal from the ischial tuberosity; and (4) weakness of flexion of the knee with a loss of normal outline of the hamstring muscles on the dorsal aspect of the knee. There was no roentgenologic evidence of fracture of the ischium. Surgical repair with reattachment of avulsed muscles to the ischium and proximal tendinous sheaths of the muscles restored function or corrected deformity.

A Stabilometric Technique for Evaluation of Functional Instability in Anterior Cruciate Ligament-deficient Knee

Abstract The standing balance of 11 functionally stable and 15 functionally unstable knees in patients with chronic anterior cruciate ligament (ACL)-deficient joints was studied by means of stabilometry. All the patients had participated in sports on a competitive level before injury, and functional stability was defined as full return, without giving way, to the same sport at the same level as before injury. Forty physically active volunteers were studied as the reference group. When compared with the reference group, an impaired standing balance was found in the functionally unstable patients but not in the functionally stable patients. The results indicate that stabilometry is a useful method for evaluating knee functional instability objectively in competitive athletes with chronic ACL-deficient knees.

Steroid-related bilateral osteonecrosis of the patella

We present a case of bilateral osteonecrosis of the patella in a patient during steroid therapy and demonstrate the radiological, arthroscopic, and histological features. Osteonecrosis of the patella should be considered as a possible cause of knee pain in patients receiving steroid therapy.

Immunohistochemical localization of basal lamina components in the developing rat epiphyseal cartilage canals.

The purpose of this study was to investigate the relationship between the appearance of basal lamina components (Type IV collagen and laminin) and the development of cartilage canals. In the distal femoral epiphyses from developing rats, the distribution of basal lamina components in the cartilage canal was examined immunohistochemically. The formation of cartilage canals from the perichondrium was first observed on the fifth day after birth. By Day 8, a few cartilage canals penetrated the epiphyseal cartilage and considerably increased in size and length. By light microscopic immunohistochemistry, reticular structures stained with anti-Type IV collagen and antilaminin antibodies were observed in the cartilage canals. In the early development of cartilage canals, however, immunostaining by anti-Type IV collagen antibodies was weaker than that by antilaminin antibodies. In eight-day-old rats, the laminin-positive reticular structures were more densely colored and more widely distributed in the canal than the Type IV collagen-positive ones. Type IV collagen was found around the endothelial cells of the developing capillaries by electron microscopic immunohistochemistry. Laminin was observed in the cytoplasm of the mesenchymal fibroblastic cells and their pericellular matrix as well as in the capillary basal lamina. These immunohistochemical electron microscopic observations can explain the differences that are observed in Type IV collagen and laminin immunostaining patterns as cartilage canals develop. Laminin synthesized by the mesenchymal fibroblastic cells may promote the migration and the outgrowth of endothelial cells in the formation of cartilage canals.