In 1984, we reported 16 postmenopausal patients with osteoporotic vertebral fractures treated with Na fluoride (NaF), calcium (Ca) and vitamin D (D). We noted relative freedom from vertebral fractures during treatment, but a disturbing incidence of femoral fractures. We now report the current status of 17 pts followed closely on continuous treatment
During 71 patient years of treatment (range 13 mths to 9 yrs) 15 developed radiological fluorosis; 7 developed a total of 9 vertebral fractures (6 in 1st yr) and 7 (including 3 of the 7 with vertebral fractures) developed a total of 11 femoral fractures. Seven fractures were in neck, 4 in shaft. In 3 patients, fractures were bilateral. Four were incomplete (stress) fractures. Two died following femoral fracture surgery. Thirteen have been followed after NaF stopped, for 39 patient years. One further vertebral fracture and 3 femoral fracture occurred — 2 in patients with femoral fractures on NaF treatment and on the same side; both required open surgery. Bone F levels have been performed on 7 patients at the end of NaF treatment using an ion specific electrode and bone ash solutions. In 5 patients with femoral fractures, F content ranged from 0.44 to 1.06% of bone ash; in 2 patients without femoral fractures, levels were 0.34 to 0.46%. Features apparently favoring femoral fractures include (i) preexisting femoral fractures; (ii) preexisting thin or tunneled femoral cortices; (iii) high bone turnover on NaF treatment; (iv) high dosage (>80 mg NaF/d) and (v) prolonged treatment.
Since 1984 we have avoided the above, and used cyclic NaF treatment (6 months on, 3 months off) with continuous Ca and D treatment. Our initial NaF dosage has been 50-60 mg/d, thereafter aiming for serum F levels 9-11 uM and avoiding >50% increases in plasma alkaline phosphatase. Nine patients have been so treated for 11 patient years; 3 developed 6 vertebral fractures but no femoral fractures. Six non-femoral stress fractures in 3 patients have resulted.
Combined treatment with NaF, Ca and D is potent in increasing trabecular bone mass in osteoporosis. Care in patient selection, and in clinical and laboratory management is essential if femoral fractures are to be avoided.