Further pitfalls in knee arthrography.

Peripheral separations of the posterior medial meniscus, diagnosed at arthrography, may not be recognized at arthroscopy, arthrotomy or even upon examination of the resected specimen. Arthrographic recognition of an oblique buckethandle meniscal tear may be difficult when the visualized outer fragment maintains a triangular appearance. Articular cartilage defects, out of profile to the x-ray beam, may be suspected at fluoroscopy and confirmed by additional views. There is an icreased incidence of chondromalacia in symptomatic postmeniscectomy knees. Degenerative meniscal changes without arthrographically recognized discrete tears are common, particularly in older individuals. Localized lack of definition of meniscal surfaces may be the only arthrographic finding. Resected specimens invariably show surface irregularities to be more extensive than suggested radiologivally, and frequently there are unsuspected associated horizontal cleavage tears. The clinical implications of degenerated menisci are controversial. A variety of normal synovial folds can simulate the anterior cruciate ligament.