Effect of bone bank processing on bone mineral density, histomorphometry & biomechanical strength of retrieved femoral head.

BACKGROUND & OBJECTIVES: Standard processing of the bone grafts involves deep-freezing and sterilization with gamma irradiation which may alter mechanical properties of the bone graft. This study was aimed at measuring the effect of bone bank processing on the mechanical properties of bone allograft and its correlation with bone mineral density [BMD, dual-energy X-ray absorptiometry (DEXA Scan)] and histomorphometric indices. METHODS: Femoral heads retrieved from patients undergoing hip replacement surgeries were used as the material. Twenty femoral heads were under taken in the study. Each femoral head was cut into two equal cubes. One cube was subjected to BMD measurement using DEXA Scan followed by unilateral compression test. Histomorphometric indices such as trabecular number (Tb. N.), trabecular separation (Tb. S.), trabecular thickness (Tb. T.) and bone volume (B.V.) were calculated on the same specimen by a computer software. The other cube was kept in deep freezer (-76°C) for a minimum of three weeks, followed by gamma irradiation and subjected to similar tests. RESULTS: Results were compared in pre- and post-processed bone specimens. A significant loss of biomechanical strength (P<0.001) with mean a loss of 18.90 per cent was found in post-processed samples in uniaxial compression tests. Similarly, BMD (mean decrease by 13.8%, P<0.01) and histomorphometric indices such as Tb. T. (mean decrease by 12.37%, P<0.01), Tb. S. (mean increase by 12.60%, P<0.001) and B.V. (mean decrease by 20.84%, P<0.01) were found. However, Tb. N. was not significantly affected. INTERPRETATION & CONCLUSIONS: The current method of processing of bone allografts i.e. deep-freezing and gamma irradiation appeared to cause a significant reduction in the biomechanical strength of allogenic bone which was more suitable to be use in the morselized form. Appropriate consideration for decreased strength needs to be given when using allogenic bone graft as a structural graft.

Interstitial Lung Disease due to Siderosis in a Lathe Machine Worker.

Since its first description in 1936, siderosis of lung has been considered a benign pneumoconiosis due to absence of significant clinical symptoms or respiratory impairment. Subsequently, authors have questioned the non-fibrogenic property of iron. However, siderosis causing interstitial lung disease with usual interstitial pneumonia (UIP) pattern has not been described in the past. We report a case of UIP on high resolution computed tomography, proven to be siderosis on transbronchial lung biopsy in a lathe machine worker.

Malignant melanoma of the rectum.

Malignant melanoma of the rectum is an extremely rare disease. It typically presents in the fifth or sixth decade of life with nonspecific complaints such as rectal bleeding or anal pain. A timely diagnosis of anal melanoma is made even more difficult by the fact that most of the lesions lack obvious pigmentation and are even histologically amelanotic. Prognosis is very poor. Anorectal malignant melanomas spread along submucosal planes and are often beyond complete resection at the time of diagnosis. We present the radiological and pathological features seen in a 43-year-old woman diagnosed with melanoma of the rectum.