Instability of the patellofemoral joint in Down syndrome.

The knees of 210 institutionalized patients with Down syndrome were evaluated to determine the prevalence of patellofemoral instability and to assess the value of orthotic and surgical treatment. The cases of 151 non-institutionalized patients with Down syndrome were also reviewed. The patella was dislocatable or dislocated in thirty-five knees (8.3 per cent) in the institutionalized group and in twelve knees (4.0 per cent) in the non-institutionalized group. This interfered with walking in some patients, but only three of the patients were unable to walk because of patellofemoral instability. None of the institutionalized patients used any form of orthosis, and only three non-institutionalized patients used an orthosis. Eight knees in five patients had been operated on, and they had an average length of follow-up of 16.8 years. Four of these knees had a satisfactory result. Instability of the patellofemoral joint may occur in patients with Down syndrome but is rarely disabling. Almost all patients with patellofemoral instability adapted to the problem and were able to walk.