Abstract:

BACKGROUND: Previous studies analyzed prosthesis loosening and subsidence, acetabulum wearing, prosthesis stem breakage in revision following artificial bipolar femoral head replacement. Little is known regarding dislocation-induced revision.
OBJECTIVE: To analyze the causes for early dislocation of artificial bipolar femoral head after total hip replacement and explore the necessity of revision.
METHODS: Clinical data of 5 patients who underwent revision after artificial bipolar femoral head replacement from May 1995 to October 2008 were reviewed retrospectively, including 3 males, 2 females, aged 75 to 87 years, with a mean age of 81 years. The reason of revision was recent dislocation. All cases underwent one-stage revision operation, while those with bone defect had bone graft. Routine blood test and blood sedimentation were observed early after revision; Harris scores for hip joint were evaluated 6 months, 1 and 2 years after revision. X-ray was used to observe acetabular prosthesis position in the pelvis.
RESULTS AND CONCLUSION: All postoperative patients were followed up 1 year at least (1 to 4 years), and no one required revision. The mean Harris score was 88 points at the final follow up. No one had wound infection or nerve and vascular damage. There was one case with insufficient cortical bone fracture while enlarging marrow cavity. X-ray showed that the position of prosthesis was normal, with no signs of loosening or infection.  Poor surgical technique and improper operation indication were main reasons for early postoperative dislocation following bipolar artificial femoral head replacement. Because of the feature of double-action, the closed reduction is difficult while dislocation of artificial femoral head occurs and revision is necessary. When the indication is correct, and surgical skill is proficient, the revision of total hip replacement could get excellent functional outcome.