Introduction: Immobilisation osteoporosis characterised by enhanced bone resorption and suppression of bone formation in response to reduced mechanical stress. This secondary osteoporosis poses a conundrum to orthopaedic surgeon in treatment of complex fracture non union following trauma. Strontium Ranelate (SrRan) is an osteoporosis agent that has dual mode of action for enhancing osteoblastic activity and reducing osteoclastic activity. We report here a case of complex non-union femur fracture with immobilisation induced osteoporosis, in which SrRan has been used to promote bone consolidation.
Case report: A 18-years old lady skidded in her motorbike. She sustained closed left femoral shaft fracture (AO/OTA 32.B1). Upon admission, a complete resuscitation was done. In view of stable physiological condition, she underwent early total care of fracture stabilisation (broad dynamic compression plating) on day 3 of post trauma. However, one year post trauma, she had a fall at home and her implant broken. Subsequently removal of implant was done and an interlocking femoral nail was inserted. Three years post trauma, she presented with bend interlocking nail and atrophic non union. A distractive osteogenesis with mono-lateral external fixation was done after removal of nail. Fixation was further complicated with osteomyelitis, which was treated immediately. Upon resolution of infection, fracture non-union addressed with wound debridement, osteotomy of atrophic fibro-osseous bone segment, iliac bone autograft inserted, and second stage corticotomy done for bone lengthening. Prior to bone lengthening, she had limb length discrepancy of 11cm (Figure 1). She was prescribed with Strontium Ranelate 2g/day from the beginning of bone lengthening to present date. On regular follow-ups in clinic, pin site inspection, adverse effect of SrRan and radiological evidence of bone healing observed closely. On the 100th day of bone lengthening, she achieved 10cm bone lengthening without any complication (Figure 2). Currently she is waiting for her left femur to completely consolidate (Figure 3).
Discussions: Frequency of the primary osteoporosis is constantly increasing all over the world, incidence of secondary osteoporosis following trauma remains as a challenge for Orthopaedic surgeons in managing cases of non union, and complex fractures. This clinical case herein support the hypothesis of a positive effect of SrRan in secondary osteoporosis (Singh Index) and bone healing. SrRan is the only novel drug shown to promote fracture healing by improve bone remodeling and leading to better microarchitecture.The animals treated with strontium ranelate had significantly higher bone mechanical values and bone microarchitecture. The SOTI trial and TROPOS trial are the extensive international RCTs which have been conducted to assess the efficacy and safety of SrRan. These trials concluded long-term therapy with SrRan has proven to be effective in reducing fracture risk, it is well tolerated and associated with a low incidence of side effects.
Conclusion: In our experience SrRan is an effective drug to use for both osteoporosis and bone healing. The safety profile is generally favorable. Side effects are rare in proportion to the benefit achieved.
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