Screening to identify postoperative pain and cross-sectional associations between factors identified in this process with pain and function, three months after total knee replacement

Prevalence and patterns of neuropathic pain in people with chronic post-surgical pain after total knee arthroplasty

Aims

The aim of this study was to describe the prevalence and patterns of neuropathic pain over one year in a cohort of patients with chronic post-surgical pain at three months following total knee arthroplasty (TKA).

Methods

Between 2016 and 2019, 363 patients with troublesome pain, defined as a score of ≤ 14 on the Oxford Knee Score pain subscale, three months after TKA from eight UK NHS hospitals, were recruited into the Support and Treatment After Replacement (STAR) clinical trial. Self-reported neuropathic pain and postoperative pain was assessed at three, nine, and 15 months after surgery using the painDETECT and Douleur Neuropathique 4 (DN4) questionnaires collected by postal survey.

Results

Symptoms of neuropathic pain were common among patients reporting chronic pain at three months post-TKA, with half reporting neuropathic pain on painDETECT (191/363; 53%) and 74% (267/359) on DN4. Of those with neuropathic pain at three months, half continued to have symptoms over the next 12 months (148/262; 56%), one-quarter had improved (67/262; 26%), and for one-tenth their neuropathic symptoms fluctuated over time (24/262; 9%). However, a subgroup of participants reported new, late onset neuropathic symptoms (23/262; 9%). Prevalence of neuropathic symptoms was similar between the screening tools when the lower cut-off painDETECT score (≥ 13) was applied. Overall, mean neuropathic pain scores improved between three and 15 months after TKA.

Conclusion

Neuropathic pain is common in patients with chronic pain at three months after TKA. Although neuropathic symptoms improved over time, up to half continued to report painful neuropathic symptoms at 15 months after TKA. Postoperative care should include screening, assessment, and treatment of neuropathic pain in patients with early chronic postoperative pain after TKA.

Subgrouping of facilitatory or inhibitory conditioned pain modulation responses in patients with chronic knee pain. Explorative analysis from a multicentre trial

BACKGROUND

Facilitatory and inhibitory conditioned pain modulation (CPM) responses are observed in healthy volunteers and chronic pain patients, but the clinical implications for phenotyping are unknown. This study aimed to subgroup and compare chronic knee pain patients according to their CPM responses.

METHODS

This explorative, cross-sectional study included 127 patients with chronic knee pain (osteoarthritis or following total knee arthroplasty). Individual CPM responses were categorized as facilitatory (test stimuli pain intensity increased when conditioning stimuli were applied), as inhibitory (test stimuli pain intensity decreased) or as no change (defined as less than 5.3% change in pain intensity). Outcomes were clinical pain intensities, temporal summation, widespread pain, self-reported physical function, PainDETECT questionnaire and Pain Quality Assessment Scale. Data were analysed as comparisons between the inhibitory and the facilitatory groups and using multivariate linear regression models.

RESULTS

Fifty-four patients had facilitatory CPM responses, 49 had inhibitory CPM responses, and 24 showed no change in CPM response. A between-group difference was observed for self-reported physical function, with the facilitatory CPM group reporting better function (54.4 vs. 46.0, p = 0.028) and the facilitatory CPM group reported more deep pain sensations (3.2 vs. 2.0, p = 0.021). The remaining outcomes showed no between-group differences. Higher clinical pain intensity and facilitated temporal summation were associated in the facilitated CPM group but not in the inhibitory CPM group.

CONCLUSION

These explorative findings indicated that quantitative clinical and experimental differences exist between facilitatory or inhibitory CPM responses in a chronic knee pain patient population. Differences in patients' CPM responses should be further investigated to unravel possible clinical importance.

SIGNIFICANCE

Our findings confirm that conditioned pain modulation consist of inhibitory and facilitatory responders among a patient population with chronic knee pain. This explorative study indicates that patients with either facilitatory or inhibitory conditioned pain modulation could exhibit differences in pain outcomes. Subgrouping of chronic pain patients depending on individual conditioned pain modulation responses could be considered in phenotyping patients prior to inclusion in clinical trials or used for personalizing the management regime.

Factors associated with persistent postsurgical pain after total knee or hip joint replacement: a systematic review and meta-analysis

Studies have identified demographic, clinical, psychosocial, and perioperative variables associated with persistent pain after a variety of surgeries. This study aimed to perform a systematic review and meta-analysis of factors associated with persistent pain after total knee replacement (TKR) and total hip replacement (THR) surgeries. To meet the inclusion criteria, studies were required to assess variables before or at the time of surgery, include a persistent postsurgical pain (PPSP) outcome measure at least 2 months after a TKR or THR surgery, and include a statistical analysis of the effect of the risk factor(s) on the outcome measure. Outcomes from studies implementing univariate and multivariable statistical models were analyzed separately. Where possible, data from univariate analyses on the same factors were combined in a meta-analysis. Eighty-one studies involving 171,354 patients were included in the review. Because of the heterogeneity of assessment methods, only 44% of the studies allowed meaningful meta-analysis. In meta-analyses, state anxiety (but not trait anxiety) scores and higher depression scores on the Beck Depression Inventory were associated with an increased risk of PPSP after TKR. In the qualitative summary of multivariable analyses, higher preoperative pain scores were associated with PPSP after TKR or THR. This review systematically assessed factors associated with an increased risk of PPSP after TKR and THR and highlights current knowledge gaps that can be addressed by future research.

Healthcare professionals' views on implementing the STAR care pathway for people with chronic pain after total knee replacement: A qualitative study

For many people with advanced osteoarthritis, total knee replacement is an effective treatment to relieve pain and improve function. However, 10-34% of people experience chronic postsurgical pain in the months and years after total knee replacement. The Support and Treatment After Replacement (STAR) randomised controlled trial (ISCRTN92545361) evaluated the clinical- and cost-effectiveness of a new multifaceted and personalised care pathway, compared with usual care, for people with pain at three months after total knee replacement. Our objective was to identify factors promoting or inhibiting its implementation, and to inform future training and wider implementation of the pathway. We conducted a prospective process evaluation using qualitative interviews with eight Extended Scope Practitioners and six Principal Investigators from seven trial sites who were involved in delivering the STAR care pathway during the trial. We used Normalization Process Theory as a theoretical framework for qualitative data collection and content analysis. We identified that factors promoting the implementation of the pathway were quick familiarisation with the pathway, valuing patient-centredness, formalising referral processes, and increasing confidence to address neuropathic pain. Challenges to implementation were availability of time and resources, sensitivity in referral process, and ensuring collective understanding of the pathway. These findings have enabled us to make recommendations about the future implementation of the STAR care pathway and will inform the development of a training package, and updated manual for successful delivery in usual care. Furthermore, this model of care has potential value in diverse elective surgeries and pain conditions.

Is inpatient rehabilitation a predictor of a lower incidence of persistent knee pain 3-months following total knee replacement? A retrospective, observational study

Background

Moderate to severe levels of persistent knee pain have been estimated to affect up to 25% of people 3-months or more after a total knee replacement. It is unknown whether the type of rehabilitation pathway is associated with persistent high pain after surgery. Using a prospectively followed Australian cohort who underwent total knee replacement for knee osteoarthritis, this study aimed to i) report the incidence of high-intensity knee pain (defined as a score ≤ 15 on the Oxford Knee Score pain subscale) across time and ii) identify whether referral to inpatient rehabilitation was one of the predictors of persistent pain at 3-months post-surgery.

Methods

A retrospective analysis of a large prospective study was conducted using the Oxford Knee Score pain subscale to determine if participants had high pain at 3-months, 12-months and 36-months post-surgery. Relative risks for high pain at 3-, 12- and 36-months between the type of rehabilitation pathway were determined using Poisson multivariable regression with robust standard errors. The same technique was also employed to determine potential predictors, including rehabilitation pathway, of high pain at 3 months.

Results

The incidence of high pain in all participants was 73% pre-surgery and 10, 5 and 6% at 3-, 12- and 36-months respectively following knee replacement. There was a significant interaction between time and rehabilitation pathway, suggesting that the effect of the rehabilitation pathway varied across time. The incidence of high pain at 3-months did not significantly differ between those who attended inpatient rehabilitation (11.6%) and those discharged directly home (9.5%). Multivariable Poisson regression analysis identified the pre-surgical presence of high pain, co-morbid low back pain or other lower limb problem, younger age and having a major complication within 3-months following surgery as significant predictors of persistent pain whilst discharge to inpatient rehabilitation was not.

Conclusion

A small but clinically significant minority of people continued to have high pain levels at 3-, 12- and 36-months following a primary total knee replacement for osteoarthritis. Participation in an inpatient rehabilitation program does not appear to be an important predictor of ongoing knee pain.

Trial registration

The data were collected in the Evidence-based Processes and Outcomes of Care (EPOC) study, ClinicalTrials.gov Identifier: NCT01899443

Association between labor and delivery pain and postpartum pain with symptoms and clinical diagnosis of postpartum depression in patients with overweight and obesity

Purpose

Childbirth pain has been associated with the risk for postpartum depression. However, existing studies have been limited by the use of depression screening tools as outcomes, and none to date have used a structured clinical interview for DSM-V (SCID), which is considered the gold standard for psychiatric diagnoses. This study aimed to quantify the relationships between labor and postpartum pain and postpartum depression diagnosis detected by SCID, as well as depression symptoms detected by the Center for Epidemiological Studies Depression Scale (CESD) screening tool, among a high-risk cohort.

Methods

The study was a secondary analysis of a prospective observational study of a cohort of women enriched for high risk for depression, i.e., pregnant women originally enrolled in a prospective study investigating factors leading to excessive gestational weight gain. Subjects were assessed prospectively for depression using both SCID and CESD at the third trimester and at 6 months postpartum. Overweight and obesity were defined as pre-gravid body mass index (BMI) ≥ 25 kg/m2. Both vaginal and cesarean deliveries were included in the cohort. Pain scores (0–10 numeric rating scale) during childbirth and after delivery were correlated with CESD and SCID. Propensity score matching was performed with propensity groups defined as those with low–moderate postpartum pain and those with high postpartum pain. The relationships between pain measures and 6-month postpartum depression diagnosis by SCID, and between pain measures and 6-month postpartum depression symptoms by CESD, were assessed by unweighted logistic regression and by logistic regression weighted by propensity score derived by average treatment effect (ATE) adjusted for baseline covariates.

Results

There were 237 subjects in the cohort for analysis. Labor and postpartum pain were not associated with depression diagnosis by SCID at 6 months postpartum. However, postpartum pain, but not labor pain, was associated with depressive symptoms on the CESD at 6 months postpartum. Women with higher maximum postpartum pain scores had significantly higher odds of developing clinically significant postpartum depressive symptoms at 6 months, compared to those with lower pain scores in the unweighted model (OR: 1.3, 95% CI 1.0, 1.5; P = 0.005) and ATE-weighted models (OR: 1.2, 95% CI 1.0, 1.5; P = 0.03). Consistent with prior work, SCID and CESD were strongly associated, and 92.9% (13/14) of participants with postpartum depression diagnosis by 6-month SCID also showed high CESD symptomology, P < 0.0001).

Conclusions

Although labor and postpartum pain were not associated with clinical diagnosis of depression (SCID) at 6 months postpartum, postpartum pain was linked to 6-month postpartum depression symptoms. Depressive symptoms are more likely to be exhibited in women with higher postpartum pain, potentially reflecting poorer birth recovery. The contribution of postpartum pain and depressive symptoms to overall patterns of poor recovery after childbirth should be assessed further.

The STAR care pathway for patients with pain at 3 months after total knee replacement: a multicentre, pragmatic, randomised, controlled trial

BACKGROUND

Approximately 20% of people experience chronic pain after total knee replacement, but effective treatments are not available. We aimed to evaluate the clinical effectiveness and cost-effectiveness of a new care pathway for chronic pain after total knee replacement.

METHODS

We did an unmasked, parallel group, pragmatic, superiority, randomised, controlled trial at eight UK National Health Service (NHS) hospitals. People with chronic pain at 3 months after total knee replacement surgery were randomly assigned (2:1) to the Support and Treatment After Replacement (STAR) care pathway plus usual care, or to usual care alone. The STAR intervention aimed to identify underlying causes of chronic pain and enable onward referrals for targeted treatment through a 3-month post-surgery assessment with an extended scope practitioner and telephone follow-up over 12 months. Co-primary outcomes were self-reported pain severity and pain interference in the replaced knee, assessed with the Brief Pain Inventory (BPI) pain severity and interference scales at 12 months (scored 0-10, best to worst) and analysed on an as-randomised basis. Resource use, collected from electronic hospital records and participants, was valued with UK reference costs. Quality-adjusted life-years (QALYs) were calculated from EQ-5D-5L responses. This trial is registered with ISRCTN, ISRCTN92545361.

FINDINGS

Between Sept 6, 2016, and May 31, 2019, 363 participants were randomly assigned to receive the intervention plus usual care (n=242) or to receive usual care alone (n=121). Participants had a median age of 67 years (IQR 61 to 73), 217 (60%) of 363 were female, and 335 (92%) were White. 313 (86%) patients provided follow-up data at 12 months after randomisation (213 assigned to the intervention plus usual care and 100 assigned to usual care alone). At 12 months, the mean between-group difference in the BPI severity score was -0·65 (95% CI -1·17 to -0·13; p=0·014) and the mean between-group difference in the BPI interference score was -0·68 (-1·29 to -0·08; p=0·026), both favouring the intervention. From an NHS and personal social services perspective, the intervention was cost-effective (greater improvement with lower cost), with an incremental net monetary benefit of £1256 (95% CI 164 to 2348) at £20 000 per QALY threshold. One adverse reaction of participant distress was reported in the intervention group.

INTERPRETATION

STAR is a clinically effective and cost-effective intervention to improve pain outcomes over 1 year for people with chronic pain at 3 months after total knee replacement surgery.

FUNDING

National Institute for Health Research.