chapter 10: Patellar Dislocation


The natural history of recurrent dislocation is quite variable, and there are multiple treatment options (40). The occasional patient is seen with only a single dislocation in his/her lifetime. This single presentation is unusual, estimated by Heywood (8) to be at 15%. Other patients are seen with simply two or three dislocations over a period of many years and generally escape surgical intervention as long as the knee remains sta­ble in the interim. Some individuals are seen with frequent dislocation, even during be­nign activities such as walking, descending stairs, dancing, and so on. Even between dislocations, the knee is unstable and uncomfortable. Crosby and Insall (19) reported that the frequency of dislocation decreased with age in 26 patients who were treated nonoperatively. Nonetheless, one must remember that substantial articular injury oc­curs at the time of dislocation, and care must be taken to replace osteochondral frag­ments in the hope of avoiding recurrent dislocations. Arthroscopy becomes the corner­stone of decision making in this regard.

Loff and Friedebold (7) have associated the severity of a dislocation directly with poor long‑term results. They found little correlation between the number of dislocations and subsequent degenerative changes. Those patients who had pain, swelling, and disability associated with each dislocation, even if the episodes were infrequent, fared much worse than those whose episodes were frequent but associated with little disability. These same authors reported the results of conservative treatment of 32 knees affected by recurrent dislocation. Only four stabilized. The remaining 28 continued to dislocate. Such reports raise the possibility that aggressive early treatment of certain patients (those with more severe malalignment and joint damage) may improve long‑term results.





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