Effects of strontium ranelate and alendronate on bone microstructure in women with osteoporosis. Results of a 2-year study

Strontium ranelate appears to influence more than alendronate distal tibia bone microstructure as assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT), and biomechanically relevant parameters as assessed by micro-finite element analysis (μFEA), over 2 years, in postmenopausal osteoporotic women.

INTRODUCTION

Bone microstructure changes are a target in osteoporosis treatment to increase bone strength and reduce fracture risk.

METHODS

Using HR-pQCT, we investigated the effects on distal tibia and radius microstructure of strontium ranelate (SrRan; 2 g/day) or alendronate (70 mg/week) for 2 years in postmenopausal osteoporotic women. This exploratory randomized, double-blind trial evaluated HR-pQCT and FEA parameters, areal bone mineral density (BMD), and bone turnover markers.

RESULTS

In the intention-to-treat population (n = 83, age: 64 ± 8 years; lumbar T-score: -2.8 ± 0.8 [DXA]), distal tibia Cortical Thickness (CTh) and Density (DCort), and cancellous BV/TV increased by 6.3%, 1.4%, and 2.5%, respectively (all P < 0.005), with SrRan, but not with alendronate (0.9%, 0.4%, and 0.8%, NS) (P < 0.05 for all above between-group differences). Difference for CTh evaluated with a distance transformation method was close to significance (P = 0.06). The estimated failure load increased with SrRan (+2.1%, P < 0.005), not with alendronate (-0.6%, NS) (between-group difference, P < 0.01). Cortical stress was lower with SrRan (P < 0.05); both treatments decreased trabecular stress. At distal radius, there was no between-group difference other than DCort (P < 0.05). Bone turnover markers decreased with alendronate; bALP increased (+21%) and serum-CTX-I decreased (-1%) after 2 years of SrRan (between-group difference at each time point for both markers, P < 0.0001). Both treatments were well tolerated.

CONCLUSIONS

Within the constraints of HR-pQCT method, and while a possible artefactual contribution of strontium cannot be quantified, SrRan appeared to influence distal tibia bone microstructure and FEA-determined biomechanical parameters more than alendronate. However, the magnitude of the differences is unclear and requires confirmation with another method.

Vers une réhabilitation des verres scléraux ?

PURPOSE

Although old generations of scleral contact lenses were totally replaced by soft and hard contact lenses, new designs and materials have recently allowed the successful use of nonfenestrated scleral contact lenses in patients who are intolerant to regular contact lenses. These new scleral contact lenses form a bridge over the cornea, which is thus permanently bathed in a saline reservoir.

METHODS

Retrospective study in patients suffering from corneal diseases altering the vision and/or responsible for ocular discomfort, and who are intolerant to conventional contact lenses.

RESULTS

Fifteen eyes (10 patients) were fitted with specially designed scleral contact lenses. The mean follow-up was 16 months (range, 1-31 months). The scleral lenses were indicated for optical and/or therapeutic reasons: keratoconus (3 eyes), corneal grafts (7 eyes), refractive surgery (2 eyes), corneal dysplasia (2 eyes), and Stevens-Johnson syndrome (1 eye). Optical results and tolerance were excellent except for one eye.

CONCLUSION

New nonfenestrated scleral contact lenses provide a good alternative for patients who are intolerant to conventional contact lenses.