To illustrate the various validated outcome tools available to assess patients undergoing TKA, we draw from data submitted by surgeons in the province of Ontario and contributed to the Ontario Joint Replacement Registry (OJRR) and the Canadian Joint Replacement Registry (CJRR) [2
]. The original intent of this data collection was to allow continuous quality improvement, to help predict the future need for THAs and TKAs, to determine the effect of prolonged waiting times on patient outcomes, and to determine the change score in health-related quality-of-life outcomes that might be necessary for a patient to be satisfied with the procedure. Where examples of knee outcome data were unavailable in the OJRR or CJRR databases, we have relied on published TKA outcomes, either our own or those of others, to provide the necessary information. Much of the data we report has been previously published as noted. All participating patients signed an informed consent for their data to be assessed. The data collection was approved by the Ethics Review Board at the University of Western Ontario.
For patient satisfaction, we used the validated patient satisfaction score developed by Jaeschke et al. [18
]. In this satisfaction scale, a patient who was uncertain as to their outcome was classified as 0, whereas those who were dissatisfied were scored from −1 to −7 depending on their degree of dissatisfaction. If they were satisfied, they were graded +1 to +7 depending on their degree of satisfaction.
For disease-specific TKA outcomes, we most commonly used WOMAC scoring as developed by Bellamy et al. [3
] to measure pain, stiffness, and physical function. Other disease-specific outcome measures used elsewhere are discussed, particularly in comparison studies to the WOMAC score (ie, Oxford-12) [12
For patient-specific scores, the MACTAR outcome tool is often used [27
]. The MACTAR outcome tool, originally described for patients with rheumatoid arthritis, provides an individualized functional priority approach for assessing improvement in physical disability in clinical trials. For this outcome, each patient is given prompts such that they can select the top five most disabling physical or social activities for which they underwent total joint arthroplasty. The measure is scored from a 10-cm visual analog scale with 10 being the most disabling. The instrument therefore can document improvement in level of function of each of these activities postoperatively. We have not applied this approach to TKAs but illustrate the scale for THAs.
Many global health scores are available. Dunbar et al. [13
] reported the Nottingham Health Profile and the SF-12 [28
] gave the best “test-retest” reliability, but that the SF-36 [29
] and the Sickness Impact Profile demonstrated the best internal consistency reliability. In their analysis, the disease site-specific Lequesne, Oxford-12, and WOMAC outcomes also performed well. Recently, we performed a study to determine the effect of patient factors such as gender on TKA outcomes [7
], exploring WOMAC and SF-12 mental component scores (MCS) and physical component scores (PCS) in 436 female and 292 male patients in whom 843 TKAs were performed and followed for a mean of 9.5 years (Table ).
Gender comparisons: preoperative to postoperative change scores
For global health assessment, we commonly used the SF-36 or SF-12 outcomes tool as developed by Ware et al. [28
]. More recently, the EuroQol global health outcome tool has been popularized, particularly in Europe, and several authors believe this five-item tool could replace the SF-36 as a result of its higher response rate, accepting its lower responsiveness [9
A number of tests are available to assess functional outcomes after TKA. For functional capacity, we have commonly used the 6-minute walk [15
] and 30-second stair climb [10
] to assess patients undergoing TKA. Other functional capacity tools include the KOOS, which is based on the WOMAC score but has been expanded to include the outcomes of pain, activities of daily living, sport and recreation function, and knee-related quality of life [23
]. Other functional outcomes of interest include the International Knee Documentation [17
], the Lower Extremity Functional Scale [4
], and the UCLA activity-level rating [30
For cost-to-utility data, the cost-to-quality adjusted life-year is often used. This is a difficult test to perform because it requires accurate costing data that can be combined with a perceived change in outcomes [17