Incidence and risk factors for chronic pain following primary total knee arthroplasty in an irish surgical population.

Objectives: To identify the incidence and characteristics of chronic post-surgical pain (CPSP) following total knee arthroplasty and determine peri-operative influencing factors.

Methods: A representative, retrospective random sample was taken of patients who underwent total knee arthroplasty in the South Infirmary University Hospital Cork for an 18-month period. Two hundred fourteen patient charts were reviewed out of a total of 507 charts for that period to provide a 90% confidence interval.

Results: The incidence of CPSP in an Irish population 6 months after total knee arthroplasty was found to be 36.5%. The following factors were found to be statistically significant with respect to the incidence of CPSP: female sex, lack of multimodal analgesia (consisting of paracetamol, NSAID, and opioids), general anaesthesia, and lower Oxford Knee Scores at 6 months post-surgery. Age, the knee operated on, ASA grade, or greatest acuity pain, were not found to be statistically significant factors in the development of CPSP.

Conclusions: CPSP is common after total knee arthroplasty with an incidence of 36.5% at 6 months post procedure. Female sex, lack of multimodal analgesia, and lower Oxford Knee Scores were associated with increased CPSP.