DIFFICULT COMPLICATIONS AFTER HIP-JOINT REPLACEMENT - DISLOCATION

Dislocation after hip replacement occurs at an overall incidence of 2% to 3% and has significant cost and morbidity implications, Statistica lly increased incidence is observed in females and in the elderly, and after reoperation procedures, Specific causes include cup malrotation , trochanteric migration, and decreased femoral offset, Head size, leg length, and postoperative mobilization have not proven to be causativ e factors, but the posterior exposure statistically and consistently i s associated with increased instability, Extended acetabular walls do lessen the incidence of dislocation in the primary but even more signi ficantly in the revision procedure, Early (<3 months) dislocations suc cessfully are treated by 4 to 8 weeks of immobilization in 60% to 70% of instances, The most successful reoperations are those in which the specific cause of the dislocation has been defined, The success rate i s approximately 80% for cup reorientation and trochanteric advancement , Nonspecific or ill defined causes are managed successfully by surgic al intervention in only approximately 50% of cases, With extensive sof t tissue compromise, limited experience with certain salvage options i nclude the bipolar implant with a reported success rate of approximate ly 80%, Captive articular designs also seem to be successful in approx imately 70% of instances but with relatively short term followup and l ingering concerns regarding the long term integrity of the fixation.