Salmon calcitonin (Miacalcic ns 200 IU) in prevention of bone loss after hip replacement.

BACKGROUND AND AIMS: Loosening of a hip prosthesis after total arthroplasty is related to periprosthetic bone loss. Calcitonin has been used in the treatment of bone loss in osteoporosis and prevention of fractures. The main purposes of the study were firstly to evaluate the effect of calcitonin on periprosthetic bone after total hip arthroplasty, secondly investigate possible loosening of the prosthesis and thirdly examine further clinical outcome. PATIENTS AND METHODS: 60 patients who underwent total hip arthroplasty using cemented Exeter prosthesis were randomized in the treatment group (salmon calcitonin 200 IU nasal spray daily + calcium 500 mg) and the placebo group (inactive nasal spray + calcium 500 mg) for six months. Bone mineral density (BMD) was measured from different locations at the time of discharge and after six and 12 months. Dynamic histomorphometry on bone biopsies taken from femoral collum was performed. Serum bone-specific alkaline phosphatase (BAP), serum osteocalcine (OC) and cross-linked N-telopeptides (NTX) were measured after one week, one month, three months and 12 months. Clinical manifestations and the incidence of fractures and loosening of the prosthesis were followed up to eight years. RESULTS: Statistically there was not significant difference in bone histomorphometry between the groups. In both groups there was a significant BMD decrease in periprosthetic bone. However, the difference between the groups was not statistically significant. In the biochemical analysis NTX increased more in the Miacalcic group than in the placebo group (p = 0.013). There were no significant differences between the groups in serum BAP or OC even though the changes within the groups were statistically significant. No loosening of the prosthesis was seen during the follow-up and there was no need for revision of any reason. Four fractures were recorded in three patients. One patient sustained a periprosthetic fracture. All the patients with fractures were allocated in the placebo group. CONCLUSIONS: Nasal salmon calcitonin 200 IU on a daily basis does not promote any additional value on calcium substitution to prevent bone loss after hip replacement. The durability of the Exeter prosthesis was good.

Loss of bone resulting from accumulation of aluminum in bone of patients undergoing dialysis.

The effects of accumulation of aluminum on cancellous bone mass and histomorphometric parameters of bone formation and resorption are evaluated in three separate studies: a cross-sectional study in 120 patients receiving long-term maintenance dialysis, including patients with and without stainable bone aluminum; a longitudinal retrospective study in eight patients receiving hemodialysis, who had progressive accumulation of aluminum in bone. These patients had two bone biopsies 11 to 16 months apart; a longitudinal prospective study in 10 patients receiving long-term hemodialysis, who had histologically proved renal osteodystrophy and stainable bone aluminum. These patients were given deferoxamine for 9 to 12 months. Repeat bone biopsies were done thereafter, and decrease or disappearance of stainable bone aluminum was observed. The results of the independent studies demonstrate that aluminum accumulation in bone is associated not only with disturbed mineralization but also with loss of cancellous bone mass, and that removal of aluminum from bone results in gain in bone volume. The mechanisms of this phenomenon are related to a disproportionately greater effect of aluminum on bone formation than on bone resorption. The negative effect on bone formation is caused by decreased number and activity of osteoblasts, which is reversed by removal of aluminum from bone. In addition, the data show that aluminum induces suppression of bone turnover, with uncoupling between bone formation and resorption whereby the effects on bone formation exceed those on bone resorption. Thus, fractures in patients with renal failure and accumulation of aluminum may result not only from osteomalacia but also from osteopenia.