chapter 9:Patellar Subluxation



The most important clinical features are giving way and a feeling of instability or pain. These clinical symptoms are associated with many patellofemoral disorders and are per­haps most frequently mistaken for a torn medial meniscus. Subluxation is often ac­companied by tilt, so many of these patients will complain of tightness or discomfort around the patella and may report a history consistent with patellar arthrosis in the later stages of subluxation. The patient may not be specific in describing episodes of sub­luxation but reports that "something" jumps in the knee or that something is out of place momentarily, causing a sensation of instability and, particularly, of insecurity in per­forming certain movements. A history of locking is unusual. When elicited, it inevitably means something different from the locking associated with a meniscal tear. The pa­tient generally means a temporary stiffness in the knee that may appear after prolonged sitting and generally disappears after movement. Pain is generally localized anteriorly, either in the medial aspect of the patella or at the distal pole. Usually crepitus becomes an important complaint only after the clinical entity has persisted for some time, which suggests that subluxation alone, particularly if not accompanied by tilt or dislocation, may spare articular cartilage in some patients. The patient with patellar subluxation fre­quently complains of apprehension and limitation in sports because of the feeling of in­security or instability. Episodes of giving way are common, and effusion will frequently accompany such episodes. Snapping and popping are frequently noted by these patients, although such findings may be less prominent early in the clinical course and in minor recurrent subluxation.




Inside Chapter 9: