Outcomes Following Primary Total Hip or Knee Arthroplasty in Substance Misusers.

The influence of drug misuse on outcomes following primary total hip (THA) or knee (TKA) arthroplasty is poorly understood. The National Hospital Discharge Survey was used to identify patients who underwent primary THA or TKA between 1990 and 2007. Patients were divided into two groups: 1) those with a diagnosis of drug misuse (cannabis, opioids, cocaine, amphetamines, sedatives, inhalants or mixed combinations) (n=13,163) and 2) those with no diagnosis of misuse (n=8,366,327). Patients with a diagnosis of drug misuse had longer hospital stays (P<0.001), nearly eight times the odds of leaving against medical advice (P<0.001) and five times the mortality rate (P<0.001). Drug misuse was associated with higher odds (P<0.001) of complications including postoperative infection, anemia, convulsions, osteomyelitis, and blood transfusion.