Flexion-extension MRI of the upper rheumatoid cervical spine.

Seven rheumatoid arthritis patients with involvement of the upper cervical spine were evaluated with a dynamic MRI study. Lateral T1 weighted images of the upper C-spine were obtained in the flexion, extension, and neutral positions. The indications for performing the dynamic MRI were radiographic instability of the upper C-spine, myelopathy, superior migration of the odontoid process, obliteration of bony landmarks on plain radiographs, and to determine the contribution of pannus on cord configuration. The dynamic MRI clearly delineated the relationship between the odontoid, foramen magnum, and cervical spinal cord as the neck was moved through a range of motion. This aided in the selection of operative candidates in four cases, and was instrumental in determining fusion levels. In three cases with suspected myelopathy secondary to cord impingement, MRI showed no significant cord compression, and aided in the decision to treat the patients conservatively. Lateral flexion-extension MRI is the diagnostic study of choice in dynamically evaluating the upper rheumatoid C-spine.

MRI diagnosis of tuberculous vertebral osteomyelitis.

Two patients with suspected tuberculous spondylitis and one patient with previous Pott's disease were evaluated preoperatively with magnetic resonance imaging (MRI). The MRI provided more exact anatomic localization of vertebral and paravertebral tuberculous abscesses in multiple planes not previously available with more conventional diagnostic methods in the patients with suspected tuberculous spondylitis. This was helpful for localization in planning of surgical approaches. In the patient with previous Pott's disease, spinal cord compression was detected using MRI, which showed no evidence of active tuberculosis. Two case reports are offered to show the benefit of using MRI as a diagnostic technique in preoperative evaluation and as a method of monitoring treatment response of tuberculous spondylitis. The third case shows the benefit of using MRI to rule out active infection and to detect other forms of spinal pathology.

Intramedullary fixation for arthrodesis of the knee after infected total knee arthroplasty.

Knee arthrodesis with curved intramedullary rods was performed in 12 patients after infected total knee arthroplasty. The underlying pathologic condition was osteoarthritis in nine patients and rheumatoid arthritis in three patients. Nine patients with a postoperative follow-up time of greater than two years (average, 34 months; median, 29 months; longest, 55 months) were evaluated for functional results. Six patients obtained a satisfactory knee fusion in an average of 6.6 months (range, three to 11 months; median, five months). Those patients without massive bone loss preoperatively attained a fusion rate of 66.6%. Two thirds of the patients with massive bone loss attained fusion. Indications for surgery in addition to infection included massive bone loss, mixed infection with multiple organisms, infrapatellar tendon rupture, ligamentous instability, and severe valgus deformity with tibial fracture nonunion. Failure occurred in three cases. One was associated with rod breakage; another was due to massive bone resorption; and the third was in a diabetic female with infrapatellar tendon rupture. All patients with successful arthrodesis reported an absence of pain and the ability to ambulate with, at most, a walker. The use of curved intramedullary rods is a convenient technique for obtaining successful arthrodesis after infected total knee arthroplasty.