79 year old male who cannot actively straighten MCP. Evaluate for subluxed extensor tendon versus locked RCL. Evaluation is slightly limited due to the patient's involuntary contracture at the fifth MCP joint.Although the extensor tendon becomes indistinct on the axial images as it courses dorsal to the MCP joint, we suspect this is artifact related to the patient's contracture as it appears intact and in the appropriate position on the sagittal sequences. The collateral ligaments of the fifth MCP joint appear intact, and the remainder of the joint is unremarkable. The central slip of the extensor tendon can be seen inserting on the dorsal aspect of the middle phalanx. Mild osteoarthritis affects the PIP joint of the fifth digit, and there is a small amount of fluid in the joint. The lateral slips of the extensor tendon can be seen inserting along the dorsal aspect of the base of the distal phalanx, although the radial slip is relatively poorly defined which may be due to prior injury. There is edema of the subcutaneous tissues of the finger. The bone marrow signal intensity is within normal limits. There is a slight swan-neck deformity of the fifth finger.
Nonspecific edema of the subcutaneous fat of the fifth finger with osteoarthritis of the PIP joint and other findings as described above. The extensor tendon of the MCP joint appears intact and in the appropriate position. We see no evidence of collateral ligament injury.