Acute delirium and poor compliance in total hip arthroplasty patients with substance abuse disorders.

From the joint registry of 2831 primary total hip arthroplasties (2351 patients) performed between 1998 and 2003, we identified 15 patients (16 hips) who had a documented history of substance abuse disorders at the time of the index surgery. The patients included 13 men (14 hips) and 2 women (2 hips), with the mean age of 49 years (range, 29-65 years). On the basis of the criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, 13 patients had alcohol abuse disorders, 1 had amphetamine abuse disorder, and 1 had heroin abuse disorder. We found high rates of postoperative substance withdrawal delirium and psychosis (46%), late complication (25%), and lost to follow-up (27%) in these patients. Because patients with substance abuse disorders have unexpected perioperative psychotic episodes, poor compliance, and a tendency to not follow medical advice after surgery and show early discontinuation of follow-up, we suggest that surgeons should work with other medical professionals and carefully perform total hip arthroplasty in such patients.

The position of the bipolar cup reflects the direction of the hip contact force acting on it.

We radiographically measured the bipolar cup position to analyze the direction of joint force acting on the bipolar cup. The abduction angle of the bipolar cup was measured in each radiograph taken immediately and at six 12 weeks and yearly after the operation. Radiographs in patients with weight bearing were also investigated. The results indicated that the abduction angle of the bipolar cup was 24.1 degrees +/- 11.2 degrees immediate postoperatively and was 16.2 degrees +/- 5.1 degrees at 6 weeks, 16.1 degrees +/- 5.1 degrees at 3 months, and 16.2 degrees +/- 5.1 degrees at 1 year. The cup abduction angles with weight bearing were not different from those without weight bearing and were 15.9 degrees +/- 4.9 degrees , 16.2 degrees +/- 4.4 degrees , and 16.1 degrees +/- 4.7 degrees on the supine, double-legged stance, and single-legged stance radiographs, respectively. Because the position of the bipolar cup reflects the direction of loads pivoting on it, the direction of the joint force in the frontal plane acting on the bipolar prosthesis is about 16 degrees to vertical.