Abstract
Significance
In spite of evidence that total knee replacement (TKR) surgery is effective, numerous studies have demonstrated that approximately 20 percent of patients who have undergone TKR surgery are not satisfied. This relatively high rate of patients who are not satisfied is the result of unmet patient expectations. The strongest predictor of dissatisfaction after TKR is unmet expectations (RR = 10.7, Bourne, Chesworth, et al, 2010). This is confirmed by Dunbar, Richardson, and Robertsson (2013): “Unmet expectation seems to be a major cause of unsatisfactory outcomes and satisfaction is most strongly correlated with relief of pain, followed by improvement in physical function.” Objective: To develop patient reported outcome (PRO) recovery graphs for knee function, activity level, and pain relief to be used as a shared decision making tool for total knee replacement surgery.
Methods
A proprietary joint arthroplasty database of patient reported outcomes (PROs) was analyzed to determine the recovery curve means and standard deviations of four PROs at six time points: pre-operatively, 6 weeks, 3 months, 6 months, 1 year, and 2 years post-operatively for total knee replacement surgery. The recovery graphs are stratified by percentile (10%, 26%, 50%, 75%, and 90%) The PROs analyzed were: (1) European quality of life (EQ-5D); Oxford Knee Score (OKS); (3) Lower Extremity Activity Scale (LEAS); and (4) Likert Pain Scale (LPS). The minimum clinically important difference (MCID) was calculated using a distribution method where the MCID equals one half the standard deviation of the score change, MCID = σΔ/2. The LEAS and LPS are used to measure patients’ expectations for pain relief and activity improvement. Prior to discussing surgery, patients are asked to report their pre-operative pain and activity levels and to specify their expected pain relief and activity improvement one year after surgery.
Results
EQ-5D: MCID 0.086, mean pre-op 0.695, 1 year post op 0.845, mean change 0.150 (1.74 MCIDs). Oxford Knee Score: MCID 4.55, mean pre-op 25.7, 1 year post op 39.7, mean change 14.0 (3.08 MCIDs). Lower Extremity Activity Scale: MCID 1.61, mean pre-op 9.08, 1 year post op 10.82, mean change 1.74 (1.08 MCIDs). Likert Pain Scale: MCID 1.26, mean pre-op 5.98, 1 year post op 1.41, mean change −4.57 (3.63 MCIDs). Stratified recovery graphs for Oxford Knee Score, Lower Extremity Activity Scale, and Likert Pain Scale are attached.
Conclusions
Pain relief (3.63 MCIDs) and improved knee function (3.08 MCIDs) will be the most dramatic improvements for patients undergoing total knee replacement surgery. Stratified recovery graphs can be used as a shared decision making tool to manage both realistic and unrealistic expectations. The recovery graphs delineate the time course for rehabilitation. Patients typically do not exceed their pre-operative activity level until three months after surgery.
