Ranawat Award Paper: Predicting Total Knee Replacement Pain

Abstract

To describe the natural history of pain after total knee arthroplasty and to identify factors predicting excessive postoperative pain, we used a prospective, observational study assessing clinical and radiographic variables preoperatively and at 1, 3, 6, and 12 months after knee replacement. Data sources included the visual analog pain scale and other measures of patient health, psychologic state, and component reliability. Regression analyses were conducted to identify specific factors predictive of postoperative pain, controlling for inequality of variables, and confirmed using regression diagnostics. For 116 patients (149 knees; mean age, 66 years; 55.2% women), significant pain was reported by 72.3%, 44.4%, 22.6%, 18.4%, and 13.1%, respectively. No intergroup differences existed for anesthesia, weight, age, or gender. Patients with greater preoperative pain had more postoperative pain, used more home therapy, and postoperative manipulations. Preoperative depression and anxiety were associated with heightened pain at 1 year. Pain after knee replacement resolves quickly, declining to approximately (1/2) by 3 months. However, one in eight patients report moderate to severe pain 1 year after surgery despite an absence of clinical or radiographic abnormalities. Development of office-based preoperative screening tools and interventions for these patients may reduce postoperative costs and improve patient-perceived outcomes.

Improving patients’ experience and outcome of total joint replacement: the RESTORE programme

“…Six cohorts reported outcomes in hip replacement, 49,51,58,102-104 and 11 in knee replacement patients. 47,49,50,58,102,[105][106][107][108][109][110] The main reasons for exclusion at this stage were lack of a pain outcome separate from an overall outcome score or the presentation of results as means only. Patient and study characteristics are summarised briefly in Table 1 and in more detail with outcome data in Appendix 4.…”

“…105 Two studies were in patients from multiple centres, 58,102 six studies were in patients treated at a single centre 47,[106][107][108][109][110] and one study reported all patients operated on by one surgeon. 50 Cohorts were generally similar with regard to patient age (range of means or medians 66-76 years) and sex (range of percentage female 54-86%), and the indication was osteoarthritis in ≥ 94% of patients when specified. Losses to follow-up ranged from 0% to 43.5%.…”

“…[46][47][48] However a significant minority of patients have persistent moderate or severe long-term pain and functional difficulties after joint replacement despite what appears to be otherwise successful surgery. [49][50][51][52][53] This fact has been obscured by the reporting of mean changes and averages for groups, ignoring the fact that although most people improve after hip or knee joint replacement, some improve more than others and some get little or no improvement or are worse after surgery than they were before it. 54 Pain and functional problems can impact on a patient's usual activities and those suffering from chronic long-term pain may be unable to return to work or leisure activities, and require a higher level of care from relatives and friends.…”

“…47,49,50,58,102,[105][106][107][108][109][110] Pain outcome measures were based on the WOMAC and Knee Injury and Osteoarthritis Outcome Score (KOOS) pain scales, the Oxford Knee Score (OKS) pain dimension or pain measured on a visual analogue scale (VAS). One study was in patients recruited from a national joint registry.…”

“…In this section we summarise results from 22 studies of pre-operative BMI, mental health, pain and physical function as predictors of long-term patient-reported outcomes. 46,50,127,[147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163][164][165] One study included important data in a second publication. 166 Details of studies are summarised in Appendix 6 with brief details in Table 5.…”