Most previous studies found that the rate of dislocation following primary THA was 2 to 3 % on average. It is expected that minimally invasive (MI) THA has fewer dislocations after surgery because it causes less muscle damage. To ascertain the risk factors of dislocation, we conducted a retrospective study of the occurrence of dislocation after MI-THA in Japanese patients. From June 2003 when we began MI-THA to August 2010 primary MI-THAs were performed on 2,042 hips; 1,997 hips with mini-posterior approach (a mean incision of 7 cm) with the repair of posterior soft tissues and 45 hips with other approaches. The dislocation after MI-THA was studied with respect to age, sex, body mass index, the use of navigation system, femoral head size, cup size and approaches. The period of follow-up was from six weeks to seven years.BACKGROUND & AIM
METHODS