Background/Purpose: Total knee replacement (TKR) outcome is often assessed with measures of pain and function (fxn), but there is no consensus on whether surgery should be evaluated as extent of improvement on these scores (“journey”) or final score (“destination”). We addressed this question by evaluating whether improvement (journey) or final score (destination) is more closely associated with patient satisfaction with TKR.

Methods:  We analyzed data from a prospective, multicenter cohort undergoing TKR.  Subjects completed the WOMAC Pain and Fxn scales (0-100, 100 worst) preoperatively and 6 months postoperatively.  At 6 months patients also completed a question on satisfaction with results of TKR. We defined the journey criterion as improvement by the minimal clinically important difference following TKR, ≥23 points on the WOMAC Pain or ≥19 on WOMAC Fxn Scale (Escobar et al). The destination criterion was the Patient Acceptable Symptom State following TKR, <31 on WOMAC Fxn (Tubach et al).  We calculated the number of subjects who achieved the journey criterion, the destination criterion, both or neither. In each group, we calculated the proportion who reported being dissatisfied, somewhat satisfied and very satisfied with surgery. We used ordinal logistic regression to examine independent effects of achieving journey or of achieving destination criteria on satisfaction with TKR.

Results: 329 subjects were included, mean age 66, 57% female. Mean preoperative WOMAC Pain and Fxn scores were 40 (sd 18) and 42 (sd 17) respectively. 238 subjects (72%) met both journey and destination criteria for success while 10 (3%) met neither criterion.  63 subjects (19%) achieved the destination criterion but not journey, while 18 patients (5%) achieved the journey criterion but not destination. Among subjects who achieved the destination but not the journey criteria, 59% were very satisfied and only 6% were dissatisfied (Figure). Among those who achieved the journey but not the destination criteria, 44% were very satisfied and 33% were dissatisfied. In ordinal logistic regression models that adjusted for age, sex and baseline WOMAC Fxn, achieving the destination criterion had a stronger association with satisfaction (OR 7.7, 95% CI 3.2, 18) than the journey (OR 2.2, 95% CI 1.0, 4.7). This finding was essentially unchanged when we excluded the 30 subjects with preoperative WOMAC Fxn scores < 19, who were not eligible to achieve the journey criterion.

Conclusion: Improvement in outcome score (journey) and final score (destination) are distinct metrics for assessing results of surgery. In this TKR cohort, both metrics were associated with patient satisfaction with the results of TKR, with destination having a stronger association than journey.  These data suggest that both journey and destination criteria should be integrated into patient-centered assessment of TKR.