Predictors of outcomes of total knee replacement surgery

Rheumatology (Oxford). 2012 Oct;51(10):1804-13. doi: 10.1093/rheumatology/kes075. Epub 2012 Apr 24.


Objective: To identify pre-operative predictors of patient-reported outcomes of primary total knee replacement (TKR) surgery.

Methods: The Elective Orthopaedic Centre database is a large prospective cohort of 1991 patients receiving primary TKR in south-west London from 2005 to 2008. The primary outcome is the 6-month post-operative Oxford Knee Score (OKS). To classify whether patients had a clinically important outcome, we calculated a patient acceptable symptom state (PASS) for the 6-month OKS related to satisfaction with surgery. Potential predictor variables were pre-operative OKS, age, sex, BMI, deprivation, surgical side, diagnosis, operation type, American Society of Anesthesiologists grade and EQ5D anxiety/depression. Regression modelling was used to identify predictors of outcome.

Results: The strongest determinants of outcome include pre-operative pain/function-those with less severe pre-operative disease obtain the best outcomes; diagnosis in relation to pain outcome-patients with RA did better than those with OA; deprivation-those living in poorer areas had worse outcomes; and anxiety/depression-worse pre-operative anxiety/depression led to worse pain. Differences were observed between predictors of pain and functional outcomes. Diagnosis of RA and anxiety/depression were associated with pain, whereas age and gender were specifically associated with function. BMI was not a clinically important predictor of outcome.

Conclusion: This study identified clinically important predictors of attained pain/function post-TKR. Predictors of pain were not necessarily the same as functional outcomes, which may be important in the context of a patient's expectations of surgery. Other predictive factors need to be identified to improve our ability to recognize patients at risk of poor TKR outcomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Arthritis, Rheumatoid / rehabilitation
  • Arthritis, Rheumatoid / surgery*
  • Arthroplasty, Replacement, Knee / rehabilitation*
  • Female
  • Humans
  • Knee Joint / surgery*
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / rehabilitation
  • Osteoarthritis, Knee / surgery*
  • Pain / rehabilitation
  • Pain / surgery
  • Patient Satisfaction
  • Postoperative Period
  • Predictive Value of Tests
  • Prognosis
  • Prospective Studies
  • Quality of Life
  • Treatment Outcome