(AAOS 2014) A prospective registry study in the UK shows that for patients with all but the most severe knee OA, the most important gains from knee replacement surgery will be in pain rather than in physical function.
New information from orthopaedic surgeons at the University of Oxford should help manage the expectations of patients considering knee replacement surgery. Their study finds that patients undergoing total knee arthroplasty (TKA) find knee pain more bothersome than loss of function before surgery, and the predominant benefit of surgery will be relief of that pain.
The results reported by the team last week at the American Academy of Orthopaedic Surgeons meeting in New Orleans came from analysis of outcomes information on all patients undergoing TKA in the UK from two large datasets, using the Oxford Knee Scores (OKS) instrument. The OKS is a 12-question survey that asks patients to score the condition of the affected knee, with responses for each question on a five-point scale. Possible scores range from 0 to 48, with lower scores indicating greater severity.
The team led by orthopaedic surgeon Andrew Price MD standardized pain and function questions into a common scale of 0 to 100 points. Assessing responses from 55,706 patients undergoing TKA between April 2009 and September 2011, they found that before surgery, irrespective of the total OKS score, all patients graded their pain as worse than their level of functional disability (36/100 compared to 45/100).
After surgery, pain improved more than function (79/100 versus 70/100). For those with the most severe preoperative knee OA (OKS scores below 16), the improvement in function may have been greater relative to the pain relief, because the difference between the two post-operative features was less pronounced.
The bottom line: For most of your patients who opt for knee replacement surgery, while movement and stability of the knee will improve, the most noticeable benefit will be in pain relief.