THE PROGNOSIS AND TREATMENT OF DISLOCATED TOTAL HIP ARTHROPLASTIES WITH A 22 MM HEAD

We studied the risk of recurrent dislocation in 121 primary and 39 rev ision Charnley or Charnley hybrid total hip arthroplasties which had b een treated for a primary dislocation between 1979 and 1995. Only 35% of these hips had no further dislocation or a revision for instability within one year, The rates of survival gradually declined with time o r if a second, third or fourth dislocation occurred, The risk of recur rence was greater in men, but was not related to age, diagnosis, time of the first dislocation or whether the index operation had been a pri mary or a revision procedure. Operative treatment included 15 reoperat ions leaving intact components, 50 revisions, and permanent removal of the femoral stem in seven patients, The operation was successful in f our patients with reoperations and in 36 who had an exchange procedure within two years. Treatment was successful in 35 of 49 hips in which it was possible to correct a technical error compared with 5 out of 16 hips in which malposition of the components was not seen (p = 0.007).