Differences in bone histomorphometry between White postmenopausal women with and without atypical femoral fracture after long-term bisphosphonate therapy

AUTHORS

Shijing Qiu, Ruban Dhaliwal, George Divine, Elizabeth Warner, Sudhaker D Rao

ABSTRACT

Bone histomorphometric endpoints in transilial biopsies may be associated with an increased risk of atypical femoral fracture (AFF) in patients with osteoporosis who take antiresorptives, including bisphosphonates (BPs). One way to test this hypothesis is to evaluate bone histomorphometric endpoints in age-, gender-, and treatment time-matched patients who either had AFF or did not have AFF. In this study, we performed transiliac bone biopsies in 52 White postmenopausal women with (n = 20) and without (n = 32) AFFs, all of whom had been treated for osteoporosis continuously with alendronate for 4–17 yr. Despite the matched range of treatment duration (4–17 yr), AFF patients received alendronate for significantly longer time (10.7 yr) than non-AFF patients (8.0 yr) (P = .014). Bone histomorphometric endpoints reflecting microstructure and turnover were assessed in cancellous, intracortical, and endocortical envelopes from transilial biopsy specimens obtained from BP-treated patients 3–6 mo after AFF and from non-AFF patients with similar age-, gender-, and range of BP treatment duration. However, in both cancellous and intracortical envelopes, AFF patients had significantly lower wall thickness (W.Th) and higher osteoclast surface (Oc.S/BS) than non-AFF patients. In addition, AFF patients had significantly higher eroded surface (ES/BS) only in the intracortical envelope. None of the dynamic variables related to bone formation and turnover differed significantly between the groups. In conclusion, in the ilium of BP-treated patients with osteoporosis, AFF patients have lower thickness of superficial bone (lower W.Th) of the cancellous and cortical envelopes than non-AFF patients. AFF and non-AFF patients have a similar bone turnover rate in the ilium. Furthermore, in this population, as in previous work, AFF is more likely to occur in BP-treated patients with longer treatment duration.

In vivo imaging tools for functional assessment of biomaterials implanted bone regeneration

AUTHORS

Subhasis Roy, Prasenjit Mukherjee, Samit Kumar Nandi

ABSTRACT

Since the discovery of X-rays and its first use in imaging of a hand, bone tissue has been the chapter of interest in medical imaging. However, X-ray imaging poses limitations nowadays owing to the augmented complexity of implant scaffolds as well as with the advances in bone engineering. As a result, advanced follow-up imaging techniques are of paramount necessity for effective postoperative characterization. Moreover, it is also needed to search for non-invasive, high-sensitivity, and high-resolution structural, functional, and molecular imaging techniques such as acoustic, optical, magnetic, X-Ray, electron, ultrasound, and nuclear imaging, etc. as an alternative to normally used X-ray computed tomography. Further, enthusiastic preclinical scanners have turned out to be accessible, with sensitivity and resolution even superior to clinical scanners, as a consequence helping a rapid transformation from preclinical to clinical applications. Besides, recently, bone-specific probes and contrast agents are developing for better imaging tools in bone-tissue engineering applications. This review highlights such emerging preclinical imaging tools, each with its individual potencies and flaws, either used only or in combination. In particular, multimodal imaging will significantly add to improve the present understanding in the characterization of bone regenerative processes.