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We performed a biomechanical study of seventeen hip joints in the pelves of nine cadavera in order to assess the role that the acetabular labrum and the transverse acetabular ligament play in load transmission. The distribution of contact area and pressure between the acetabulum and the femoral head was measured with the hip in four different conditions:(More)
Microcracks in bone have been implicated in the development of stress fractures. The goal of this study was to evaluate bone strain and microcracks at locations where stress fractures are common (second metatarsal diaphysis) and rare (fifth metatarsal diaphysis) in an attempt to increase our understanding of the pathogenesis of stress fractures. A dynamic(More)
Resistance exercise has positive effects on bone mass, but little is known about the mechanisms by which this occurs. The purpose of this study was to determine if a single bout of moderate intensity resistance exercise alters biochemical markers of bone cell activity. Indices of bone turnover were measured in nine healthy, untrained men (21.9 +/- 1.2 yrs(More)
The function of the infraspinatus, teres minor, and subscapularis during elevation of the arm remains poorly defined. These muscles may generate moments that contribute to abduction of the arm, although they frequently are classified as humeral depressors. The purposes of this study were to measure the contributions to abduction made by the more inferiorly(More)
BACKGROUND The plantar aponeurosis is known to be a major contributor to arch support, but its role in transferring Achilles tendon loads to the forefoot remains poorly understood. The goal of this study was to increase our understanding of the function of the plantar aponeurosis during gait. We specifically examined the plantar aponeurosis force pattern(More)
The hip is a common site of orthopaedic trauma and disease, and considerable research has been directed toward understanding the development of contact pressures within the joint. Virtually all experimental studies to date have employed proximal femurs compressed along the joint reaction force vector into acetabulae explanted from cadaver pelves. This(More)
A previous study of coralline hydroxyapatite as a bone-graft substitute was extended from 4 to 12 months to determine better the relationships between implantation time, bone ingrowth and mechanical properties. The model consisted of a 10 x 30 mm window defect in the shaft of the canine radius (a cortical site), and a 10 mm diameter cylindrical defect in(More)
BACKGROUND Results of shoulder arthroplasty have been reported to be inferior with posterior glenoid wear and accompanying subluxation of the humeral head. The purpose of this study was to examine the effect of posterior glenoid wear on posterior subluxation of the humeral head. MATERIAL AND METHODS A custom loading device was used to simulate physiologic(More)
Metatarsal stress fractures occur in military recruits after long marches and in athletes after episodes of overtraining involving running or jumping. It has been demonstrated that contraction of the plantar flexors of the toes helps to counteract the moments placed on the metatarsals by body weight. It is possible that physiological fatigue due to(More)
Incorporation of physiologic muscle tensions to simulate normal in vivo joint loading in cadaveric biomechanical studies has been a challenging problem, especially about the knee, foot, and shoulder. Simulation of muscle contraction requires attachment of tension producing devices to musculotendinous units. To this end, we modified the 'cryo-jaw' device,(More)