Friday Conference 11/22/02:  from Christine Lamoureux

1. The pattern of ACL injury and medial femorotibial edema is often associated with a medial meniscal tear. Similarly, proximal fibular edema is often associated with injury to the posterolateral corner.
2. In distinguishing an infected disk vs mechanical/degenerative disk: less than 10 % of cases with a vacuum disk phenomenon will have an infection in the disk. A pre-existing vacuum disk can lose the gas in the disk when it becomes infected. If there is a question of spondylolisthesis due to degenerative facet disease vs infection, a hyperextension lateral fim of the spine can draw gas into the disk, effectively excluding infection. If this fails, an MRI is a good next option.
3. Septic arthritis in the presence of rheumatoid arthritis: staph is common. Look for large effusions, ill-defined bone destruction, and rapid rate of distruction as signs of infection.
4. Dermatomyositis in the region of the knee on plain film: results in sheet-like calcifications in the soft tissues anteriorly and posteriorly. The differential includes scleroderma (more tuftal, or tumor-like calcification), and lupus (globular calcification).
5. C-spine fusions: the "wasp-waist" appearance of vertebral body fusion is indicative of fusion occurring early in life. If the spinous processes are not fused, then the process is not developmental.
6. Deforming nonerosive arthropathy: the differential includes Jacoud’s arthropathy (from rheumatic fever) with a clinical pattern of ulnar-sided arthritis in the hand involving the 4^th and 5^th fingers, ulnar deviation and Boutineer’s deformities, Ehlers-Danlos, and probably disuse with resultant joint space loss and chronic deforming arthritis.
7. HAD (hydroxyapatite deposition): affects the ulnar side of the wrist most commonly (can involve the flexor carpi ulnaris tendon). Pain and swelling over the pisiform and distal ulna can also be present. It is associated with collagen/vascular diseases or chronic renal failure. The calcification and swelling can go away, and when aspirated, the deposits have a toothpaste-like consistency. The tophaceous deposits of gout and those of CPPD look different. HADD has different appearances according to srage—it may have a fluid level, which is good for determining whether it is amenable for aspiration. It also has a more organized form and can erode bone.