Poor histological healing of a femoral fracture following 12 months of oestrogen deficiency in rats.

SUMMARY: Fractures in post-menopausal osteoporosis cause significant morbidity; however, animal models for post-menopausal fracture healing lack the effect of ageing. Therefore, we developed a model using aged animals with chronic oestrogen deficiency, which demonstrates inferior fracture repair (decreased healing histologically, bone mineral density and content and strength). This novel model may help develop molecular strategies for osteoporotic fracture repair. INTRODUCTION: The femur is susceptible to damage by both systemic conditions such as osteoporosis and locally by traumatic injury. The capacity for fracture repair decreases with age, while the risk of fracture increases. As studies of osteoporotic fracture healing in rats traditionally use a period of 3 months or less of oestrogen deficiency prior to fracturing, we aimed to establish a osteoporosis model in rats with chronic oestrogen deficiency by 12 months to better mimic human female osteoporosis. METHODS: Seventy female Sprague-Dawley rats (10 weeks old) were ovariectomised or sham operated and housed for 12 months. The right femur was fractured by way of an open osteotomy and fixed with an intramedullary Kirschner wire. Animals were sacrificed at 1, 3 and 6 weeks for radiography, dual-energy X-ray absorptiometry, tensile testing and histology. RESULTS: Bone mineral density and bone mineral content were lower by 60 and 63 %, respectively, (p < 0.05) in the bilaterally ovariectomized (OVX) groups than those in the sham groups at 6 weeks in the right fractured femurs. Maximum breaking force of the OVX group was lower than that of the sham group, with the greatest difference seen at 6 weeks following osteotomy. Histologically, the OVX groups demonstrated a delay in cellular differentiation within the fracture callus and the presence of bone resorption. The sham animals had a superior histological healing pattern with an Allen score of 4 at 6 weeks compared to a score of 1 for the OVX groups (p < 0.01). CONCLUSIONS: Long-term ovariectomy has a deleterious effect on fracture healing in a rodent model.

Clinical significance of intrasubstance meniscal lesions on MRI.

Grade 2 meniscal changes on MRI are linear signals confined within the meniscus thought to represent areas of meniscal degeneration or intrasubstance tears. It has been reported that in only 10% of cases is a meniscal tear detected during subsequent arthroscopy. Usually non-operative management is appropriate, but in some cases, grade 2 meniscal changes are seen on MRI in patients with a typical presentation of a meniscal tear. In this circumstance, an arthroscopic partial meniscectomy may be indicated and an MRI report, which describes the meniscus as being normal, may be confusing. A pilot study of 10 consecutive symptomatic patients (mean age 28.1 years) with a grade 2 meniscal signal on MRI was performed. At arthroscopy, with thorough examination of the meniscus using a probe, an intrasubstance tear was detected in all 10 patients. Partial meniscectomy was performed, with a mean follow-up of 6.7 months. All but one patient (due to other pathology) had marked improvement in pain and function. Thus, the authors believe that grade 2 signal changes should be reported in a manner that raises the possibility that they may cause symptoms and that the presence of any intrasubstance changes should be clearly conveyed in the report.

Isolated scaphotrapeziotrapezoid osteoarthritis: preliminary results of treatment using a pyrocarbon implant.

The scaphotrapeziotrapezoid (STT) joint is the second most common site in the wrist affected by degenerative arthritis. STT fusion has been the traditional treatment for patients with isolated STT arthritis but there are concerns about the complication rate and loss of wrist movement post-surgery. The current study presents the results of an interposition arthroplasty using a scaphoid trapezium pyrocarbon implant (STPI, BIOProfile). Ten STPI's were implanted in nine patients (mean age 66, 58-76 years) with isolated STT arthritis. The mean follow-up was 16.4 (3-35) months. Following surgery, VAS pain scores improved significantly and most patients had minimal restrictions in function, with a mean DASH score of 21. The mean wrist flexion-extension arc was 126 degrees and radioulnar deviation was 43 degrees. Mean grip strength was 82% and pinch strength 85% compared to the non-operated side. Patients were highly satisfied with the results of their surgery (mean VAS score 9.1). No surgical complications were encountered and no significant changes in carpal alignment were noted on radiographs. The results of this study suggest that STPI interposition arthroplasty may be a good alternative to STT fusion for isolated STT arthritis.