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Journal of Bone and Joint Surgery - British Volume, Vol 91-B, Issue 4,
545-551.
doi: 10.1302/0301-620X.91B4.21355 Copyright © 2009 by British Editorial Society of Bone and Joint Surgery Is a valgus position of the femoral component in hip resurfacing protective against spontaneous fracture of the femoral neck?A BIOMECHANICAL STUDYC. Schnurr, MD, Orthopaedic Surgeon1; J. Nessler, Orthopaedic Surgeon1; C. Meyer, MD, Radiologist2; H. H. Schild, MD, Professor2; J. Koebke, MD, Professor3; and D. P. König, MD, Professor1
1 Rheinische Klinik für Orthopädie, Horionstrasse 2, 41749 Viersen, Germany. Correspondence should be sent to Dr C. Schnurr; e-mail: christophschnurr{at}gmx.de
The aim of our study was to investigate whether placing of the femoral component of a hip resurfacing in valgus protected against spontaneous fracture of the femoral neck. We performed a hip resurfacing in 20 pairs of embalmed femora. The femoral component was implanted at the natural neck-shaft angle in the left femur and with a 10° valgus angle on the right. The bone mineral density of each femur was measured and CT was performed. Each femur was evaluated in a materials testing machine using increasing cyclical loads. In specimens with good bone quality, the 10° valgus placement of the femoral component had a protective effect against fractures of the femoral neck. An adverse effect was detected in osteoporotic specimens. When resurfacing the hip a valgus position of the femoral component should be achieved in order to prevent fracture of the femoral neck. Patient selection remains absolutely imperative. In borderline cases, measurement of bone mineral density may be indicated.
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