PROGNOSIS OF DISLOCATION AFTER TOTAL HIP-ARTHROPLASTY

One hundred sixty-one dislocations after cemented total hip arthroplas ty, with a mean follow-up period of 8 years after dislocation, were re viewed with the aim of establishing the prognosis. There were 84% sing le and 16% recurrent dislocations. Closed reduction was successful in 81% of cases. Thirty-seven percent of dislocations were early (within 5 weeks), 36% occurred in patients who had had previous surgery, and i n 47% there was nonunion of the trochanter. There was a two-way intera ction between these factors, and all factors were significant for recu rrent dislocation. Twenty-six (16%) recurrent dislocations required su rgery. The most common causes of recurrent dislocation demonstrated at operation were component malposition (58%) and failure of the abducto r mechanism (42%). In total, 96% of cases were successfully treated.