Treatment strategies for proximal femur fractures in osteoporotic patients

Abstract

Fractures of the proximal end of the femur, together with vertebral fractures, are greatly exacerbated by osteoporosis and can be regarded as the most typical and most serious complications of this disease. The demand for prompt mobilisation with full loading of the affected limb, combined with a desire for the gentlest of treatments, becomes increasingly difficult to meet in ageing patients with advanced osteoporosis. The advantages of osteosynthesis in respect to these demands when operating on elderly patients with fractures do not apply due to the inability of the osteoporotic bone to hold the osteosynthetic components sufficiently until fracture healing occurs. This inability is related to the anatomy of the proximal end of the femur and its loading patterns. Under eccentric loading, high bending loads occur, leading to failure of the osteosynthetic anchorage at the center of the femoral head. This leads subsequently to stressful revision operations for the patient. The prosthetic replacement is a good option in cases of dislocated intracapsular fractures, but in cases of trochanteric fractures it is still debated. Therefore, it is vital for the trauma surgeon to have specific knowledge of the patient's bone quality in order to optimise the result of the preferred procedure. With reference to our own experimental research and a study of the current literature, this knowledge can be summarised as follows: the most stable anchorage for the implant is achieved by placing the implant through the midpoint of the femoral head (highest bone mineral density) or just below ("best backing"). Anchoring femoral head implants so that they are stable in rotation within the head-neck fragment will significantly raise their load bearing capacity. This is also true for intramedullary load bearing devices in trochanteric fractures. The distance between the load-bearing device in the femoral neck and the articular surface is inversely correlated to the stability at yield, as other studies have already shown. There seems to be a limit for a successful realisation of an osteosynthesis that lies at a femoral head bone mineral density of 250 mg/cm(3) calcium-hydroxyapatite (CaHAp). Nevertheless, high precision surgery in regard to fracture reduction and implant placement is a essential requirement for a successful osteosynthesis. Reproducible local measurements of bone mineral density and trabecular alterations, as well as quick screening methods, are very much desired by the authors.

Reason and treatment of failure of proximal femoral nail antirotation internal fixation for femoral intertrochanteric fractures of senile patients

“…The incidence of this disorder has increased markedly in recent years owing to continuously aging populations (Bonnaire et al, 2005). Proximal femur nail antirotation (PFNA) is a new internal fixation system that was recently developed and is now applied widely in various intertrochanteric fractures.…”

Estimation of Femoral Head Bone Mineral Density in Hip Fractures of the Elderly

“…Therefore, little is available to avoid fixation failure following hip fracture, such as proper patient selection, optimal reduction of the fracture and proper positioning of the fixation devices. Although significant differences were demonstrated between different regions of proximal femur by using quantitative CT, the difference between DXA measurements of different regions of proximal femur is not as much as expected (4). The reason for this may be due to 2D nature of the measurement by DXA, and effect of neighboring cortical bone on x-ray absorption.…”

“…But this finding has not been validated clinically. Also a BMD range of 260-370 mg/cm 3 calcium hydroxyapatite (CaHAp) at femoral head center was described as necessary to ensure stable fixation of hip fractures (1,4).…”

Computational analyses of small endosseous implants in osteoporotic bone

“…Despite the success small threaded endosseous implants have achieved in modern orthopedic and dental medicine, there are still cases in which they do not perform well. Biomechanical studies have shown that prevailing small endosseous implants show decreased performance when implanted into bone with low density, such as evoked by osteoporosis (Bonnaire et al, 2005;Koistinen et al, 2005;Seebeck et al, 2004). It appears evident that there is potential to enhance implant performance.…”