In this study pneumoroentgenography, using atmospheric air, was done on fifty knee joints.
Hypertrophy of the retropatellar fat pad, indicative of chronic synovitis or injury, was demonstrated in twenty-one knees. The pad was palpably enlarged in only seven patients.
Baker's cysts were demonstrated in four knees.
Fracture of the meniscus was diagnosed by pneumoroentgenography in 71 per cent. of the knees in which fractured menisci were found at eration. Three knees remained unoperated.
Displacement of a meniscus was diagnosed in 91 per cent. of the knees in which a displaced cartilage was found on arthrotomy.
Fracture-displacement of a meniscus was verified by arthrotomy in 100 per cent. of the knees in which this diagnosis was made.
Loose bodies were diagnosed in eight knees and removed from the three knees operated upon. One undemonstrated pedunculated body was found at operation.
Thirty-two knees had suffered a twist; in twenty-four, or 75 per cent., the accident had occurred while the knee was flexed. In twenty-four, or 48 per cent. of the fifty cases, there had been limitation of extension.