Long-term outcome of patients with avascular necrosis, after internal fixation of femoral neck fractures.

We retrospectively reviewed 84 patients who underwent internal fixation of an intracapsular femoral neck fracture. The mean age was 58 years and the time from injury to operative treatment was 5.3 days. The mean follow-up was 4.7 years (range, 2-8 years). At the latest follow-up, in the 46 patients with undisplaced (Garden I, II) fractures, nonunion occurred in two patients and avascular necrosis of the femoral head in nine. Six of these nine patients had a good or excellent result, one had a fair result, and two had a poor result. Of 35 patients with no sign of avascular necrosis, 32 patients had a good or excellent result, two a fair and one had a poor result. In the group of 38 patients with displaced (Garden III, IV) fractures, nonunion occurred in six patients and avascular necrosis of the femoral head in 15. Of these 15 patients, 10 had a good or excellent result, two had a fair result, and three had a poor result. Of 17 patients with no sign of avascular necrosis, 14 had an excellent result and three patients a poor result. Overall only five of the 24 patients who developed avascular necrosis of the femoral head had undergone total hip arthroplasty. Internal fixation remains a simple and safe, method of treatment for both undisplaced and displaced femoral neck fractures in middle-age patients. Despite the relatively high rate of avascular necrosis after internal fixation of femoral neck fractures, only a few of these patients (20%) required further surgical treatment in the follow-up period of this study.

Degenerative spondyloarthropathy of the cervical and lumbar spine in jockeys.

This prospective study analyzed the long-term effects of horse riding on the cervical and lumbar spine of jockeys. Thirty-two jockeys were observed for 13 years. All jockeys had clinical and radiographic evaluation of the spine; three consecutive age groups were studied. Results were compared to age-matched, normal population control groups. The incidence of degenerative changes of the spine was higher in the jockeys compared with the control groups and was more prominent in the older age group for both the lumbar and cervical spine. These findings suggest that equestrian sports, particularly professional horse riding, apart from the increased risk of direct spinal injury caused by a fall from the horse, can lead to progressive spine degeneration as a result of repetitive trauma and increased physical stress on the spine.

Influence of orthotopic placement on the incorporation and mechanical strength of a loaded structural cortical graft: an experimental study in rabbits.

The biological and mechanical behavior of loaded cortical autografts were evaluated in an experimental study using 40 adult male New Zealand rabbits divided into 4 groups. A double osteotomy was performed on all animals at the mid-diaphysis of the right ulna. The bone segment (5 mm) in between the osteotomies was considered a cortical autograft and fixed with an intramedullary Kirschner wire. The graft was fixed in an orthotopic manner in groups A and C, and rotated 180 degrees in groups B and D. After the animals were sacrificed (at 2 months for groups A and B and at 4 months for groups C and D), bone mineral density, graft cross-sectional geometry, and SSI index were assessed. Mechanical testing of the grafted area was carried out using a three-point bending configuration, and the parameter fracture load was assessed. Graft union and incorporation also was studied in histologic sections. In group C (orthotopic graft placement--4 months), bone specimens showed statistically significantly higher values for fracture load, total cross-sectional area, volumetric total bone mass and density, and polar SSI (P values < or = .05) compared to the other groups. In the same group, union and incorporation of the graft was complete, the cortex showed low porosity, and the collagen fibers were mature and properly oriented. Structural cortical bone autografts placed in an orthotopic manner recognize the new mechanical environment as optimal and thus their biological and mechanical behavior are enhanced. Loaded structural cortical grafts should be placed in an orthotopic manner when used for the management of cortical bone defects.