Regional migratory osteoporosis of the knee: a literature overview.

The purpose of this article is to review the clinical syndrome of regional migratory osteoporosis (RMO) of the knee and to highlight all the important aspects of diagnosis and management that can be helpful to the physician. RMO is a rare, self-limiting disease characterized by migrating arthralgia, bone marrow edema and osteoporosis. The pathogenesis of RMO remains controversial and is not yet fully elucidated. A thorough presentation of the disease is conducted with presentation of the clinical features (progressive pain and local tenderness), differential diagnosis and appropriate diagnostic criteria. The role of MRI is underlined and strategies for the treatment of RMO are presented.

Calcitonin effect on Achilles tendon healing. An experimental study on rabbits.

OBJECTIVE: A positive potential effect of Calcitonin (CT) on Achilles tendon healing was investigated as well as the ability of MRI to follow the tendon healing process. MATERIALS AND METHODS: A standardized tenotomy of the Achilles tendon was performed on forty-two rabbits. Twenty-one animals received daily 21 IU /kg Calcitonin intramuscularly (treatment group CT) during the experiment and the remaining received saline solution (control group P). Seven animals from each group were killed at one, two and three weeks postoperatively. All animals had serial MRI scans and tendon samples underwent biomechanical and histological testing. RESULTS: For both groups, animals of the same subgroup showed statistically significant difference in signal intensity values of MRI between the 1st and 3rd week (p<0.001) and between the 2nd and 3rd week (p<0.001). Signal intensity values of MRI didn't show any differences between animals under treatment and controls measured at 1st (p=0.23), 2nd (p=0.23) and 3rd (p=0.53) postoperative week. Tendon samples from group CT showed statistically significant difference in ultimate tensile strength compared to controls at 2 (p<0,0005) and 3 (p<0,0005) weeks post-surgery. Histology showed a positive Calcitonin effect at all tendon healing stages. CONCLUSION: It is suggested that Calcitonin enhances Achilles tendon healing process.

Radiological evaluation of the metal-bone interface of a porous tantalum monoblock acetabular component.

Between January 1998 and December 1998, 82 consecutive patients (86 hips) underwent total hip arthroplasty using a trabecular metal monoblock acetabular component. All patients had a clinical and radiological follow-up evaluation at six, 12 and 24 weeks, 12 months, and then annually thereafter. On the initial post-operative radiograph 25 hips had a gap between the outer surface of the component and the acetabular host bed which ranged from 1 to 5 mm. All patients were followed up clinically and radiologically for a mean of 7.3 years (7 to 7.5). The 25 hips with the 1 to 5 mm gaps were studied for component migration at two years using the Einzel-Bild-Roentgen-Analyse (EBRA) digital measurement method. At 24 weeks all the post-operative gaps were filled with bone and no acetabular component had migrated. The radiographic outcome of all 86 components showed no radiolucent lines and no evidence of lysis. No acetabular implant was revised. There were no dislocations or other complications. The bridging of the interface gaps (up to 5 mm) by the trabecular metal monoblock acetabular component indicates the strong osteoconductive, and possibly osteoinductive, properties of trabecular metal.

An MRI-based semiautomated volumetric quantification of hip osteonecrosis.

OBJECTIVE: To objectively and precisely define the spatial distribution of osteonecrosis and to investigate the influence of various factors including etiology. DESIGN: A volumetric method is presented to describe the size and spatial distribution of necrotic lesions of the femoral head, using MRI scans. The technique is based on the definition of an equivalent sphere model for the femoral head. PATIENTS: The gender, age, number of hips involved, disease duration, pain intensity, limping disability and etiology were correlated with the distribution of the pathologic bone. Seventy-nine patients with 122 hips affected by osteonecrosis were evaluated. RESULTS: The lesion size ranged from 7% to 73% of the sphere equivalent. The lateral octants presented considerable variability, ranging from wide lateral lesions extending beyond the lip of the acetabulum, to narrow medial lesions, leaving a lateral supporting pillar of intact bone. Patients with sickle cell disease and steroid administration presented the largest lesions. The extent of the posterior superior medial octant involvement correlated with the symptom intensity, a younger age and male gender. CONCLUSION: The methodology presented here has proven a reliable and straightforward imaging tool for precise assessment of necrotic lesions. It also enables us to target accurately the drilling and grafting procedures.