The Influence of Fat Infiltration of Back Extensor Muscles on Osteoporotic Vertebral Fractures

STUDY DESIGN: Retrospective study. PURPOSE: To investigate the influence of fat infiltration at low back extensor muscles on osteoporotic vertebral fracture. OVERVIEW OF LITERATURE: In persons with stronger back muscles, the risk of osteoporotic vertebral fractures will likely be lower than in those persons with weaker back muscles. However, the degree of influence of fat infiltration of the back extensor muscle on osteoporotic vertebral fracture remains controversial. METHODS: Two hundred and thirty-seven patients who had undergone lumbar spine magnetic resonance imaging and bone mineral density (BMD) were enrolled in this study. The amount of low back extensor muscle was determined using the pseudocoloring technique on an axial view of the L3 level. The patients were divided into two groups: osteoporotic vertebral fracture group (group A) and non-fracture group (group B). The amount of low back extensor muscle is compared with BMD, degenerative change of disc, osteophyte grade of facet joint and promontory angle to reveal the association between these factors. RESULTS: A negative correlation is found between age and the amount of low back extensor muscle (p=0.001). The amount of low back extensor muscle in group A and group B was 60.3%+/-14.5% and 64.2%+/-9.3% respectively, thus showing a significantly smaller amount of low back extensor muscle in the osteoporotic vertebral fracture group (p=0.015). CONCLUSIONS: Fat infiltration of low back extensor muscle was increased in osteoporotic vertebral fracture patients. Therefore, fat infiltration of low back extensor muscle in an elderly person may be a risk factor of osteoporotic vertebral fracture.

The Causes and Treatment of Dislocations after Total Hip Arthroplasty

A dislocation after total hip arthroplasty is a serious complication that is related to the component position and poor patient compliance. Therefore, the attendants and surgeons need to be aware of the risk factors for dislocations and take steps to prevent them. In addition, the surgeon should insert the components within the safe zone. The patients should also be informed of possibility of dislocations after total hip arthroplasty. Dislocations can be treated conservatively but a recurrent dislocation requires surgery. The causes of recurrent dislocations must be evaluated before surgery to achieve a high success rate.