Outcomes of total hip and knee replacement: Preoperative functional status predicts outcomes at six months after surgery

Abstract

Objective. To determine whether patients with knee or hip osteoarthritis (OA) who have worse physical function preoperatively achieve a postoperative status that is similar to that of patients with better preoperative function.Methods. This study surveyed an observational cohort of 379 consecutive patients with definite OA who were without other inflammatory joint diseases and were undergoing either total hip or knee replacement in a US (Boston) and a Canadian (Montreal) referral center. Questionnaires on health status (the Short Form 36 and Western Ontario and McMaster Universities Osteoarthritis Index) were administered preoperatively and at 3 and 6 months postoperatively. Physical function and pain due to OA were deemed the most significant outcomes to study.Results. Two hundred twenty-two patients returned their questionnaires. Patients in the 2 centers were comparable in age, sex, time to surgery, and proportion of hip/knee surgery. The Boston group had more education, lower comorbidity, and more cemented knee prostheses. Patients undergoing hip or knee replacement in Montreal had lower preoperative physical function and more pain than their Boston counterparts. In patients with lower preoperative physical function, function and pain were not improved postoperatively to the level achieved by those with higher preoperative function. This was most striking in patients undergoing total knee replacement.Conclusion. Surgery performed later in the natural history of functional decline due to OA of the knee, and possibly of the hip, results in worse postoperative functional status.

Education Attainment is Associated With Patient-reported Outcomes: Findings From the Swedish Hip Arthroplasty Register

“…In a German population, positive associations were found with increases in the WOMAC in patients who completed their education after 12 years as compared with those with only 8 years of education; however, it is not clear whether these improvements were in all three WOMAC subscales [24]. Similar to what we report, Fortin et al [8] found that greater education attainment was associated with lower pain and better function 6 months after arthroplasty independent of preoperative pain or functional status. Conversely, Keurentjes et al [16] found no association with THA outcomes and education.…”

“…In the literature, associations between education and surgical outcomes have been explored using numerous patient-reported outcome measures [2,8,16,24]. When investigating postoperative function, an American study found that lack of a college education was associated with poorer function after THA [2].…”

“…Finally, when investigating the effect of socioeconomic status on health, education is the least likely factor to be changed by disease [10]. Even so, there are differing accounts regarding whether an individual's socioeconomic status is associated with outcomes like functional status, HRQoL, and satisfaction after surgery [2,8,16,24]. For analyses of this sort, many of the groups studied have been relatively small with patient populations of 1000 or less.…”

Factors and Consequences of Waiting Times for Total Hip Arthroplasty

“…It also is possible that waiting only 6 months to assess the impact of a THA may have introduced bias. Although some studies report that improvement is seen at 6 months [8,9,12,25], some suggest a longer followup period is needed [20]. Third, the WOMAC provides valuable information and is considered the correct instrument for evaluating changes in studies such as ours [15,26].…”

“…We assessed all patients preoperatively and at 6-month followup, the time during which most improvements occur [12]. We collected data from the patients' hospital medical records.…”