THE "TRICK knee" is familiar to every surgeon. Often he has only the patient's word for the time of the injury, the mechanism, the number of recurrences, the local reactions, and the like. In many instances, the symptoms and signs of internal derangement of the knee are minimal, intermittent, and evasive and the exact clinical diagnosis is by no means obvious. The decision as to whether the knee can stand the rigors of military service, athletics, or hazardous industrial occupations must be based on a questionable history and minimal findings on examination. Frequently the disturbance in such a knee is labeled "functional" because of the paucity of specific complaints and localized findings.
The temptation to solve the diagnostic dilemma by exploratory arthrotomy is always present; yet the knee is a joint that is not readily accessible to complete exploration. It is compartmented. There are medial, lateral, anterior, and posterior chambers,
STACK JK, LOCKWOOD RC. PNEUMOARTHROGRAMS OF THE KNEEAn Aid in the Localization of Internal Derangement. AMA Arch Surg. 1951;63(4):486-495. doi:10.1001/archsurg.1951.01250040496009