Persistent pain after knee replacement: do factors associated with pain vary with degree of patient dissatisfaction?

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.

THE EFFECTS OF DRAINAGE TUBE ON PAIN AND FUNCTIONAL RECOVERY AFTER UNICOMPARTMENTAL KNEE ARTHROPLASTY

Objective

The objective of this study was to evaluate the impact of drainage tube placement on postoperative pain, recovery, and opioid consumption within a 72-hour period following unicompartmental knee arthroplasty (UKA).

Methods

Patients with medial knee osteoarthritis who underwent UKA from January 2019 to August 2020 were enrolled in the study and divided into two groups based on whether they received a drain postoperatively.

Results

The drainage group had significantly lower VAS scores on day 1, day 2, and day 3, in addition to significantly smaller changes in the circumference of the knee joint within 3 days postoperatively (P <0.05). The ROM in the drainage group significantly increased at 3 days and 1 month post-surgery, with a statistically significant difference in morphine consumption between the two groups at 3 days (P<0.05). The incidence of postoperative nausea and vomiting (5 cases) and wound bleeding (1 case) was lower in the drainage group compared to the non-drainage group (P<0.05).

Conclusions

The placement of a drainage tube in UKA may reduce the swelling of knee joint and pain, which not only reduces the use of Opioid but also facilitates early functional activities of the knee joint. Level of Evidence III; Retrospective Comparative Study.

Ultrasound-guided thermal radiofrequency ablation of the genicular nerves after total knee replacement

The rate of refractory chronic pain after total knee replacement (TKR) is 20-25%, with no identifiable etiology in 6% of cases. Without an etiologic diagnosis, the surgeon is unlikely to consider revision, but pain poses a therapeutic challenge for achieving satisfaction and an acceptable quality of life. Genicular nerve radiofrequency ablation (GNRFA) was recently developed as a non-drug analgesic option. It is minimally invasive and safe, with few adverse effects, opening a new perspective for management of refractory chronic pain after TKR. LEVEL OF EVIDENCE: IV.

Novel morphogenic knee implant delivers comparable mid-term outcomes as compared to conventional non-morphogenic implants

INTRODUCTION

Conventional total knee arthroplasty (C-TKA) implants have well-established mid- and long-term outcomes. The novel TKA (N-TKA) implants provide morphogenic implant components with smaller size increments to facilitate anatomical replication. The aim of the study is to evaluate if these advantages provides better clinical outcomes.

MATERIALS AND METHODS

Registry data prospectively collected within a single institution from 2014 to 2018 was reviewed and propensity score matching was performed to match C-TKA to N-TKA. 70 pairs of cruciate retaining (CR) TKA and 116 pairs of posterior stabilized (PS) TKA were identified. Range of motion, SF-36, Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS) and Oxford Knee Score (OKS) were assessed preoperatively, 6 and 24 months postoperatively. Satisfaction was assessed 6 and 24 months postoperatively. Independent T test was performed for parametric data, whereas Wilcoxon rank-sum analysis was performed for non-parametric data.

RESULTS

Both C-TKA and N-TKA cohorts demonstrated statistically significant improvement for KSKS, KSFS, OKS and SF-36 at 6 and 24 months postoperatively. C-TKA CR patients had better flexion at 6 months as compared to N-TKA CR (108.7° versus 98.3°, respectively, p = 0.046). At 24 months, there was no difference between C-TKA and N-TKA for range of motion, KSKS, KSFS, OKS and SF-36 PCS, regardless of insert type (p > 0.05).

CONCLUSIONS

Both models showed great postoperative improvements in KSFS, KSKS, OKS and SF-36 and have comparable early and mid-term outcomes, suggesting that N-TKAs are suitable substitutes for C-TKA. Longer follow-up studies are required to evaluate the long-term outcomes of N-TKAs.

LEVEL OF EVIDENCE

lll.

Peripheral nerve stimulation for the treatment of chronic knee pain

The average age of our population is increasing, resulting in a high incidence of chronic degenerative knee pathologies. Several treatment options, including surgical procedures are available to help mitigate these pathologies. However, the percentage of subjects with chronic post-surgical knee pain is still estimated at 16-20%. Neuromodulation techniques such as spinal cord stimulation and dorsal root ganglion stimulation (DRGS) are treatment options for subjects with chronic knee pain. The evidence for peripheral nerve stimulation (PNS) is minimal due to a limited number of neuromodulation systems capable of targeting the distal part of the lower limbs. This study aimed to investigate the safety and efficacy externally powered PNS systems for the treatment of chronic intractable knee pain targeting the saphenous nerve. Patients suffering from chronic intractable post-surgical knee pain received landmark-guided peripheral nerve stimulation of the branches of the saphenous nerve. All implants were performed with an externally powered PNS system to avoid lead migration as a result of cross-joint lead positions tunneling towards an Implantable Pulse Generator to the trunk. Data were collected retrospectively. Subject-reported outcome was measured via numerical rating scale values on a 10-point scale measuring pain intensity at rest and in motion. Additional data were collected for the subjects treated at the Charité location, including quality of life with the SF-36 form, quality of sleep with the Pittsburgh Sleep Quality Index and mood states with the short form of the General Depression Scale. Thirty-three patients received direct to permanent implant, landmark-guided peripheral nerve stimulation of the saphenous nerve branches. Six (18.2%) subjects reported non-sufficient initial benefit from the therapy and were explanted. Two subjects were explanted due to wound infections. The total study population reported included 25 patients. These subjects reported significant improvements related to pain, quality of life, mood quality, and quality of sleep. Additionally, subjects were able to reduce their opioid medication significantly after PNS therapy. Externally powered PNS at the saphenous nerve branches is a straightforward, selective and safe technique for patients with chronic knee pain. The landmark-guided implantation technique is less invasive than classical neuromodulation techniques such as spinal cord or DRGS and complication rates remain low. Short-term results are promising and show considerable reductions in pain scores and opioid intake. Long-term results are pending.

Identification of Metabolic Factors and Inflammatory Markers Predictive of Outcome after Total Knee Arthroplasty in Patients with Knee Osteoarthritis: A Systematic Review

OBJECTIVE

To identify metabolic factors and inflammatory markers that are predictive of postoperative total knee arthroplasty (TKA) outcome.

METHOD

A systematic search of the existing literature was performed using the electronic databases PubMed, Web of Science and Embase until the 1^st of August 2022. Studies that evaluated the influence of metabolic or inflammatory markers (I) on postsurgical outcome (O) in end-stage knee osteoarthritis patients awaiting primary TKA (P) were included in this review.

RESULTS

In total, 49 studies were included. Risk of bias of the included studies was low for one study, moderate for 10 studies and high for the remaining 38 studies. Conflicting evidence was found for the influence of body mass index, diabetes, cytokine levels and dyslipidaemia on pain, function, satisfaction and quality of life at more than six months after TKA.

CONCLUSIONS

Several limitations such as not taking into account known confounding factors, the use of many different outcome measures and a widely varying follow-up period made it challenging to draw firm conclusions and clinical implications. Therefore large-scaled longitudinal studies assessing the predictive value of metabolic and inflammatory factors pre-surgery in addition to the already evidenced risk factors with follow-up of one year after TKA are warranted.

Comparison of Patient-Reported Outcomes and Functional Assessment Using a Marker-Less Image Capture System in End-Stage Knee Arthritis

BACKGROUND

Patient self-assessment of knee function in end-stage osteoarthritis (OA) and following total knee arthroplasty (TKA) using patient-reported outcome measures (PROMs) has become standard for defining disability. The relationship of PROMs to functional performance requires a continued investigation. The purpose of this study was to determine correlations between patient demographics, PROMs, and functional performances using a marker-less image capture system (MICS).

METHODS

Patients indicated for elective TKA completed the Knee Injury and Osteoarthritis Score for Joint Replacement (KOOS-JR) and an office-based functional assessment using a MICS. Patient age, body mass index (BMI), and gender were collected. A total of 112 patients were enrolled. Their mean age was 65.0 (±9.7) years, mean BMI was 32.5 (±6.6) kg/m², and mean KOOS-JR was 14.5 (±5.7). The relationships between patient characteristics, KOOS-JR, MICS Alignment (coronal), MICS Mobility (flexion), and composite Total Joint scores were described using Spearman's correlation coefficients.

RESULTS

BMI was weakly correlated with KOOS-JR (ρ = -0.22, P = .024), whereas age was not. Age and BMI were not correlated with performance scores. There were weak to no correlations between KOOS-JR and MICS Alignment (ρ = -0.01, P = .951), Mobility (ρ = 0.33, P < .001), and Total Joint scores (ρ = 0.06, P = .504).

CONCLUSION

This study found no strong correlation between KOOS-JR and functional performance using a validated MICS for patients with end-stage knee OA. Further study is warranted in determining the relationship between PROMs and performance to optimize outcomes of patients undergoing nonoperative or surgical interventions for knee OA. The use of high-fidelity functional assessment tools that can be integrated into clinical workflow, such as the MICS used in this study, should permit PROM/functional performance comparisons in large populations.

Primary care consultations and pain medicine prescriptions: a comparison between patients with and without chronic pain after total knee replacement

BACKGROUND

Approximately 20% of patients experience chronic pain after total knee replacement (TKR). The impact of chronic pain after TKR on primary care services in the UK is currently unknown. The aim of this study was to compare primary care consultations and pain medicine prescriptions between patients with and without chronic pain after TKR.

METHODS

Data from 5,055 patients who received TKR between 2009 and 2016 with anonymised linked data from the Clinical Practice Research Datalink Gold (CPRD) and English Hospital Episode Statistics (HES) Patient Reported Outcome Measures (PROMs) programme were analysed. The exposure time was from 10 years pre-operative to eight years post-operative. Patients with a score ≤ 14 on the Oxford Knee Score pain component scale at 6 months post-operative were classified as having chronic pain after TKR. Primary care consultations and prescribed pain medicines were quantified, and costs calculated based on national cost data.

RESULTS

721 patients (14%) had chronic pain after TKR. The prevalence and costs of primary care consultations and pain medicine prescriptions per year were consistently higher for patients with chronic pain after TKR compared with those without chronic pain after TKR; these differences were observed both before and after surgery. There was a substantial and sustained increase in the cost of opioid prescriptions after surgery for patients with chronic pain after TKR, peaking at seven years post-operative.

CONCLUSIONS

Increased primary care consultations and pain medicine prescriptions associated with chronic pain after TKR represent a considerable financial cost to primary care services. Evaluation of interventions to reduce the risk of developing this pain condition and improve the early management of pain after TKR are needed to improve outcomes for patients and reduce costs to healthcare services.

Multimodal prediction of pain and functional outcomes 6 months following total knee replacement: a prospective cohort study

BACKGROUND

Knee osteoarthritis (OA) is among the most common and disabling persistent pain conditions, with increasing prevalence and impact around the globe. In the U.S., the rising prevalence of knee OA has been paralleled by an increase in annual rates of total knee arthroplasty (TKA), a surgical treatment option for late-stage knee OA. While TKA outcomes are generally good, post-operative trajectories of pain and functional status vary substantially; a significant minority of patients report ongoing pain and impaired function following TKA. A number of studies have identified sets of biopsychosocial risk factors for poor post-TKA outcomes (e.g., comorbidities, negative affect, sensory sensitivity), but few prospective studies have systematically evaluated the unique and combined influence of a broad array of factors.

METHODS

This multi-site longitudinal cohort study investigated predictors of 6-month pain and functional outcomes following TKA. A wide spectrum of relevant biopsychosocial predictors was assessed preoperatively by medical history, patient-reported questionnaire, functional testing, and quantitative sensory testing in 248 patients undergoing TKA, and subsequently examined for their predictive capacity.

RESULTS

The majority of patients had mild or no pain at 6 months, and minimal pain-related impairment, but approximately 30% reported pain intensity ratings of 3/10 or higher. Reporting greater pain severity and dysfunction at 6 months post-TKA was predicted by higher preoperative levels of negative affect, prior pain history, opioid use, and disrupted sleep. Interestingly, lower levels of resilience-related "positive" psychosocial characteristics (i.e., lower agreeableness, lower social support) were among the strongest, most consistent predictors of poor outcomes in multivariable linear regression models. Maladaptive profiles of pain modulation (e.g., elevated temporal summation of pain), while not robust unique predictors, interacted with psychosocial risk factors such that the TKA patients with the most pain and dysfunction exhibited lower resilience and enhanced temporal summation of pain.

CONCLUSIONS

This study underscores the importance of considering psychosocial (particularly positively-oriented resilience variables) and sensory profiles, as well as their interaction, in understanding post-surgical pain trajectories.

Efficacy and safety of duloxetine for postoperative pain after total knee arthroplasty in centrally sensitized patients: study protocol for a randomized controlled trial

Background

Postoperative residual knee pain after total knee arthroplasty (TKA) is a significant factor that contributes to patient dissatisfaction. Patients with preoperative central sensitization (CS) may be more susceptible to unexplained chronic pain after TKA, and duloxetine has been reported to be effective in post-TKA pain control in patients with CS. However, there remains limited evidence to support this off-label use in routine clinical practice. Hence, we designed this randomized, placebo-controlled, triple-blind clinical trial to evaluate the effects of preoperative screening and targeted duloxetine treatment of CS on postoperative residual pain compared with the care-as-usual control group.

Methods

This randomized controlled trial includes patients with knee osteoarthritis on a waiting list for primary unilateral TKA. Patients with preoperative CS will be randomly allocated to the perioperative duloxetine treatment group (duloxetine group) or the care-as-usual control group (placebo group). Patients in the duloxetine group will receive a half-dose of preemptive duloxetine (30 mg/day) for a week before surgery and a full-dose of duloxetine (60 mg/day) for six weeks after surgery. The primary outcome is the intensity of residual pain at six months after TKA, including the visual analogue scale, 11-point numeric rating scale, the sensory dimension of the brief pain inventory, and the pain subscale of the Knee injury and Osteoarthritis Outcome Score. The secondary outcome measures will include the pain and function related outcomes. All of the patients will be followed up at one, three, and six months after surgery. All adverse events will be recorded and immediately reported to the primary investigator and ethics committee to decide if the patient needs to drop out from the trial.

Discussion

This clinical trial will convey the latest evidence of the efficacy and safety of the application of duloxetine in postoperative pain control in CS patients who are scheduled for TKA. The study results will be disseminated at national and international conferences and published in peer-reviewed journals.

Trial registration

Chinese Clinical Trial Registry (http://www.chictr.org.cn) registration number: ChiCTR2000031674. Registered 07 April 2020.

Chronic postsurgical pain after total knee arthroplasty: A prospective cohort study in Japanese population

OBJECTIVES

To elucidate the prevalence and risk factors of chronic postsurgical pain (CPSP) after primary total knee arthroplasty (TKA) in Japanese population.

METHODS

Consecutive patients undergoing primary TKA in a Japanese tertiary hospital (211 knees) were assessed. CPSP after TKA was defined as moderate to severe pain (VAS >30 mm), either at rest or during walking, one year after surgery. Clinical and radiographic data were compared between CPSP and non-CPSP groups and multivariate logistic regression was used to identify predictors of CPSP.

RESULTS

The prevalence of CPSP was 8.8%. CPSP group showed significantly higher preoperative WOMAC subscales (pain, function and stiffness), higher rate of postoperative coronal malalignment (femorotibial angle >178° or <170°) and larger varus angle of tibial component compared with non-CPSP group. Logistic regression analysis revealed that preoperative higher WOMAC pain and postoperative coronal malalignment were independent risk factors of CPSP. In a subgroup analysis of patients with well-aligned TKA, preoperative pain VAS at rest was the only risk factor of CPSP.

CONCLUSION

Preoperative severe pain and postoperative coronal malalignment were independent risk factors of CPSP after TKA. Preoperative pain management in patients with severe pain and good coronal alignment after TKA possibly minimize the development of CPSP.

Reduction in anxiety and depression symptoms one year after knee replacement: a register-based cohort study of 403 patients

Background

Anxiety and depression are associated with patient dissatisfaction after total knee arthroplasty (TKA). Understanding whether preoperative knee-related symptoms could be a cause of anxiety and depression might help prevent unnecessary delay of surgery for this group of patients. We investigated changes in prevalence of anxiety and depression symptoms one year after TKA, and compared demographic data between patients with and without anxiety and depression symptoms preoperatively.

Methods

This was a prospective cohort study of 403 patients scheduled for TKA. Data on patient-related outcome measures and the prevalence of anxiety and depression symptoms were collected preoperatively and one year postoperatively. Before–after differences in anxiety/depression prevalence were compared with a chi-square test, and differences in demographic data between the groups with and without anxiety and/or depression symptoms were compared with an independent t test.

Results

Among the 15% of patients with anxiety symptoms before surgery, 59% had improved in these symptoms one year after surgery; while among the 10% with depression symptoms before surgery, 60% had improved one year after surgery. Patients with preoperative anxiety and/or depression were younger, and had higher body mass index, lower general quality of life (EQ-5D-3L), higher pain scores (visual analog scale), and lower knee-related (KOOS) scores on all subscales except sport.

Conclusion

Presurgical symptoms of anxiety and depression seem to be partly caused by knee symptoms. Understanding of this issue would offer better strategies to prevent unnecessary delay of surgery in this group of patients.

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

Objective

To describe the screening and recruitment process of a randomized trial and evaluate associations with knee pain and function 3 months after total knee replacement (TKR).

Methods

In order to screen for a multicenter trial, a total of 5,036 patients were sent the Oxford Knee Score (OKS) questionnaire 10 weeks post‐TKR. Patients who reported pain in their replaced knee (score of ≤14 on the OKS pain component) completed a second OKS questionnaire 12 weeks post‐TKR. Those patients who were still experiencing pain 12 weeks post‐TKR completed a detailed questionnaire 13 weeks post‐TKR. These data were used to characterize pain in a cross‐sectional analysis. Multivariable regression was performed in order to identify factors associated with pain and function at 13 weeks post‐TKR.

Results

We received OKS questionnaires from 3,058 of 5,063 TKR patients (60%), and 907 of the 3,058 (30%) reported pain in their replaced knee 10 weeks post‐TKR. By 12 weeks, 179 of 553 patients (32%) reported improved pain (score of >14 on the OKS pain component). At 13 weeks, 192 of 363 patients (53%) who completed a detailed questionnaire reported neuropathic pain, 94 of 362 (26%) reported depression symptoms, and 95 of 363 (26%) anxiety symptoms. More severe pain at 13 weeks postoperatively was associated with poorer general health, poorer physical health, more pain worry, and lower satisfaction with surgery outcome. More severe functional limitation was associated with higher levels of depression, more pain worry, lower satisfaction with surgery outcome, and higher pain acceptance.

Conclusion

Screening after TKR identified individuals with pain. We identified several potential targets (physical and mental health outcomes, acceptance of pain, and quality of life) for tailored intervention to improve outcomes for patients. Future trials of multidisciplinary interventions warranted.

Radiofrequency Procedures for the Treatment of Symptomatic Knee Osteoarthritis: A Systematic Review

OBJECTIVE

To evaluate the effectiveness and safety of radiofrequency (RF) ablation and neuromodulation modalities for knee osteoarthritis (OA).

METHODS

The Pubmed, Medline, Embase, and Cochrane Library databases were searched from inception to August 2018. All comparative and noncomparative studies that reported clinical outcome measures and adverse events related to RF modalities for knee OA were included. Pain scores, physical function measures, quality of life (QOL), patient satisfaction, and adverse events for three months and beyond of postprocedure follow-up were analyzed qualitatively.

RESULTS

Thirty-three studies, including 13 randomized controlled trials (RCTs), two nonrandomized comparative studies, and 18 noncomparative cohort studies, were identified, with 1,512 patients (mean age = 64.3 years, 32.5% males). All 33 studies were considered to be of moderate or high methodological quality. All 33/33 (100%) studies reported alleviation of OA-related knee pain from baseline until three to 12 months with RF modalities, with six comparative studies reporting 194/296 (65.5%) and 29/150 (19.3%) RF and control patients achieving >50% pain relief, respectively. Three of the 33 studies reported QOL, with three of three studies (100%) achieving improvements in disease-specific QOL from baseline until three to 12 months. Twenty-eight of the 33 studies reported functional outcomes, with 27/28 (96%) studies obtaining enhanced functionality from baseline up until three to 12 months. Ten of the 33 studies reported patient satisfaction, with eight of 10 studies (80%) indicating that patients were significantly satisfied after RF procedures, and from these eight studies, four were comparative studies that indicated that 86/154 (56%) and 33/104 (32%) RF and control patients were extremely satisfied or satisfied, respectively. Regarding adverse events (AEs), 29 of the 33 studies reported AEs, with 20/29 (69%) studies indicating no AEs related to the RF modalities and the remaining nine studies only indicating minor localized AEs. Twenty-nine of the 33 studies indicated no serious knee-related AEs pertaining to RF modalities.

CONCLUSIONS

Current evidence substantiates that RF modalities for knee OA potentially improve pain, functionality, and disease-specific QOL for up to three to 12 months with minimal localized complications. This suggests that RF modalities are perhaps an effective adjunct therapy for patients with knee OA who are unresponsive to conservative therapies. Further RCTs with larger sample sizes and long-term follow-up that directly compare the three primary RF modalities are warranted to confirm the clinical efficaciousness and superiority of these RF modalities for knee OA.

Depression and Anxiety Are Risk Factors for Postoperative Pain-Related Symptoms and Complications in Patients Undergoing Primary Total Knee Arthroplasty in the United States

BACKGROUND

The study was designed to analyze the underlying relationship between psychiatric comorbidities and postoperative outcomes in patients undergoing primary total knee arthroplasty (TKA).

METHODS

We used the National Inpatient Sample data from 2002 to 2014. On the basis of the International Classification of Disease, Ninth Revision, Clinical Modification, we divided TKA patients into 4 subgroups: those diagnosed with depression, those diagnosed with anxiety, those concomitantly diagnosed with both depression and anxiety, and those without depression or anxiety. The chi-squared test and analysis of variance were performed to measure differences among these 4 subgroups. Multiple logistic regression analysis was used to determine whether psychological comorbidities were independent risk factors for postoperative complications and surgery-related pain.

RESULTS

A total of 7,153,750 patients in the United States were estimated to have undergone TKA between 2002 and 2014. The prevalence of depression, anxiety, or both diagnoses in TKA patients significantly increased over time. Patients with psychiatric disorders showed higher hospital costs but shorter periods of hospitalization, with higher odds ratios for most complications and all pain-related symptoms observed in this study.

CONCLUSION

The prevalence of depression and anxiety in TKA patients is increasing steadily each year. Psychiatric disorders were closely correlated with the outcomes of TKA. The mental health of patients undergoing TKA needs more attention to ensure adequate relief from postoperative pain-related symptoms as well as quality of life.

Central Sensitization Is a Risk Factor for Persistent Postoperative Pain and Dissatisfaction in Patients Undergoing Revision Total Knee Arthroplasty

BACKGROUND

The objective of this study is to investigate whether central sensitization (CS) was associated with patient dissatisfaction after revision total knee arthroplasty (TKA).

METHODS

Between 2012 and 2016, 68 cases (68 patients) of revision TKA performed by a single surgeon were included in this study with a minimum follow-up of 2 years. Patients were categorized into 2 groups by 40-point preoperative Central Sensitization Inventory (CSI) scores. The control group consisted of 48 patients (48 knees) with CSI scores of less than 40 points, while the CS group consisted of 20 patients (20 knees) with CSI scores of 40 points or more. Clinical outcomes were evaluated using an 11-point visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index scores. Patient satisfaction was evaluated using the satisfaction items of the new Knee Society Scores, where scores ≥20 indicated satisfaction.

RESULTS

Higher preoperative pain VAS scores in the CS group were maintained 3, 6, 12, and 24 months postoperatively (all P < .05). The CS group showed significantly worse pain, function subscores, and total scores of the Western Ontario and McMaster Universities Osteoarthritis Index preoperatively and at 2 years postoperatively. Forty-four (91.7%) patients in the control group and 3 (15.0%) patients in the CS group were satisfied with their revision TKAs (P < .001). Multivariate logistic regression analysis demonstrated that the odds of dissatisfaction after revision TKAs were increased 39.081 times (95% confidence interval 6.926-220.504, P < .001) in patients with CSI scores ≥40. Higher VAS intensity 2 years postoperatively also predicted dissatisfaction following revision TKA (odds ratio 1.864, 95% confidence interval 1.086-3.199, P = .024).

CONCLUSION

CS is a risk factor for persistent postoperative pain and dissatisfaction in patients undergoing revision TKAs.

LEVEL OF EVIDENCE

III.

Pre-operative pressure pain thresholds do not meaningfully explain satisfaction or improvement in pain after knee replacement: a cohort study

OBJECTIVES

Pain sensitization could be a risk factor for poor outcomes after knee replacement surgery (KR) for knee osteoarthritis (KOA). We aimed to evaluate the association between pre-operative central and peripheral pain sensitization measured using a digital pressure algometer and KR outcomes.

METHODS

Consecutive patients with severe KOA listed for KR were recruited. Sociodemographic and symptoms data were collected prior to surgery. Pre-operative pressure pain thresholds (PPTs) were measured using a digital pressure algometer at the index knee and forearm. Patient satisfaction at 6 and 12 months after KR was assessed using a 4-point Likert scale, and dichotomized to satisfied and dissatisfied to KR. Western Ontario and McMaster Universities Index (WOMAC) Pain and function was assessed. The associations between pre-operative PPTs with KR outcomes at 6 and 12 months were evaluated.

RESULTS

Of the 243 patients recruited, response rate at 6 and 12 months were 95.5% and 96.7%. The dissatisfaction rates were 8.2% and 5.1% at 6 and 12 months. There was no statistically significant association between pre-operative index knee or forearm PPTs and patient satisfaction. PPTs measured at the knee, but not the forearm, were weakly associated with change in the WOMAC pain score at 12 months, after adjustment for confounding factors.

CONCLUSION

Pre-operative central sensitization, measured by handheld digital algometry, was not statistically significantly associated with satisfaction or change in pain after KR. Pre-operative peripheral sensitization was associated with change in pain symptoms after KR; however, this association was weak and unlikely to be a meaningful predictor of KR outcome in clinical practice.

Predictive Factors for Developing Chronic Pain After Total Knee Arthroplasty

Total knee arthroplasty offers substantial improvements for patients as measured by functional status and quality of life; however, 8% to 34% of patients experience chronic postsurgical pain following surgery (CPSP). In addition to disruption in daily activities of life caused by the pain itself, CPSP has been associated with an overall reduction in quality of life following surgery. Risk factors for CPSP can be broadly defined as potentially modifiable or unlikely modifiable. Unlikely modifiable risks include gender, age, medical comorbidities, and socioeconomic status. Potentially modifiable risks include perioperative pain, physical function, psychological state, surgical factors, and possibly genomics. Understanding risks and the magnitude of their effect on outcomes such as CPSP is desirable because interventions designed to affect these factors may be able to dramatically improve outcomes.

Does overstuffing of the patellofemoral joint in total knee arthroplasty have a significant effect on postoperative outcomes?

BACKGROUND

There is ongoing debate in the literature as to whether or not patellofemoral joint overstuffing has a clinically significant effect on postoperative outcomes following total knee arthroplasty (TKA). This study investigates the effect of patellofemoral joint overstuffing on patient-reported outcomes using novel methods of radiographic measurement.

METHODS

The study population consisted of a prospective cohort of 266 patients receiving a Triathlon® (Stryker, Kalamazoo, MI, USA) TKA between 2006 and 2009. Participants completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire preoperatively and at 12 months postoperatively. Pre- and postoperative radiographic measurements were taken according to a defined protocol to assess for patellofemoral overstuffing. Measurement reproducibility was assessed using inter-observer intraclass correlation coefficients. Associations between radiographic measurements and patient-reported outcomes were analysed using linear regression analysis.

RESULTS

A total of 107 patients had adequate images and were included in the analysis for this study. Three different radiographic measurements were used to identify patellofemoral overstuffing all with good intra- and inter-observer reliability. There was no association identified between combined (patella and trochlea) patellofemoral overstuffing measurements and WOMAC scores. However, a statistically significant association was identified between an increase in anterior trochlear offset and worse knee pain and function scores (P < 0.05).

CONCLUSIONS

There is no identifiable association between true patellofemoral overstuffing and clinical outcome; however, there is a small association with the anterior trochlear offset though further studies are warranted to confirm the clinical significance of this finding.

Chronic pain after total knee arthroplasty

Despite a good outcome for many patients, approximately 20% of patients experience chronic pain after total knee arthroplasty (TKA).

Chronic pain after TKA can affect all dimensions of health-related quality of life, and is associated with functional limitations, pain-related distress, depression, poorer general health and social isolation.

In both clinical and research settings, the approach to assessing chronic pain after TKA needs to be in-depth and multidimensional to understand the characteristics and impact of this pain. Assessment of this pain has been inadequate in the past, but there are encouraging trends for increased use of validated patient-reported outcome measures.

Risk factors for chronic pain after TKA can be considered as those present before surgery, intraoperatively or in the acute postoperative period. Knowledge of risk factors is important to guide the development of interventions and to help to target care. Evaluations of preoperative interventions which optimize pain management and general health around the time of surgery are needed.

The causes of chronic pain after TKA are not yet fully understood, although research interest is growing and it is evident that this pain has a multifactorial aetiology, with a wide range of possible biological, surgical and psychosocial factors that can influence pain outcomes.

Treatment of chronic pain after TKA is challenging, and evaluation of combined treatments and individually targeted treatments matched to patient characteristics is advocated. To ensure that optimal care is provided to patients, the clinical- and cost-effectiveness of multidisciplinary and individualized interventions should be evaluated.

Cite this article: EFORT Open Rev 2018;3:461-470. DOI: 10.1302/2058-5241.3.180004

A 2-year RSA study of the Vanguard CR total knee system: A randomized controlled trial comparing patient-specific positioning guides with conventional technique

Background and purpose - There is some concern regarding the revision rate of the Vanguard CR TKA in 1 registry, and the literature is ambiguous about the efficacy of patient-specific positioning guides (PSPGs). The objective of this study was to investigate the stability of the cemented Vanguard CR Total Knee using 2 different surgical techniques. Our hypothesis was that there is no difference in migration when implanting the Vanguard CR with either PSPGs or conventional technique. We hereby present a randomized controlled trial of 2-year follow-up with radiostereometric analysis (RSA). Patients and methods - 40 TKAs were performed between 2011 and 2013 with either PSPGs or the conventional technique and 22 of these were investigated with RSA. Results - The PSPG (8 knees) and the conventional (14 knees) groups had a mean maximum total point motion (MTPM) (95% CI) of 0.83 (0.48-1.18) vs. 0.70 (0.43-0.97) mm, 1.03 (0.60-1.43) vs. 0.86 (0.53-1.19), and 1.46 (1.07-1.85) vs. 0.80 (0.52-1.43) at 3, 12, and 24 months respectively (p = 0.1). 5 implants had either an MTPM >1.6 mm at 12 months and/or a migration of more than 0.2 mm between 1- and 2-year follow-ups. 2 of these also had a peripheral subsidence of more than 0.6 mm at 2 years. Interpretation - 5 implants (3 in the PSPG group) were found to be at risk of later aseptic loosening. The PSPG group continuously migrated between 12 and 24 months. The conventional group had an initial high migration between postoperative and 3 months, but seemed more stable after 1 year. Although the difference was not statistically significant, we think the migration in the PSPG group is of some concern.

Selective peripheral nerve resection for treatment of persistent pain around the knee joint after total knee arthroplasty

Objective This study was performed to determine the efficacy of selective peripheral nerve resection for treatment of persistent neuropathic pain after total knee arthroplasty (TKA). Methods Patients who underwent TKA in our department from January 2013 to July 2016 and experienced persistent pain around the knee joint after TKA were retrospectively included in the current study. Sixty patients were divided into experimental and control groups according the treatment they received. The treatment effect was evaluated by the Hospital for Special Surgery (HSS) knee score and visual analog scale (VAS) pain score preoperatively and at 1, 2, 3, 6, and 12 months postoperatively. Results The HSS knee scores were higher in both groups after than before the treatment, and HSS knee scores were significantly higher in the experimental group than in the control group. The VAS pain scores were lower in both groups after than before the treatment, and VAS pain scores were significantly lower in the experimental group than in the control group. Conclusions Selective peripheral nerve resection is an effective treatment method for persistent neuropathic pain after TKA.

Effectiveness of postdischarge interventions for reducing the severity of chronic pain after total knee replacement: systematic review of randomised controlled trials

OBJECTIVE

Approximately 20% of patients experience chronic pain after total knee replacement (TKR). The aim of this systematic review was to evaluate the effectiveness of postdischarge interventions commenced in the first 3 months after surgery in reducing the severity of chronic pain after TKR.

DESIGN

The protocol for this systematic review was registered on PROSPERO (registration number: CRD42017041382). MEDLINE, Embase, CINAHL, PsycINFO and The Cochrane Library were searched from inception to November 2016. Randomised controlled trials of postdischarge intervention which commenced in the first 3 months after TKR surgery were included. The primary outcome of the review was self-reported pain severity at 12 months or longer after TKR. Risk of bias was assessed using the Cochrane risk-of-bias tool.

RESULTS

Seventeen trials with data from 2485 randomised participants were included. The majority of trials evaluated physiotherapy interventions (n=13); other interventions included nurse-led interventions (n=2), neuromuscular electrical stimulation (n=1) and a multidisciplinary intervention (n=1). Opportunities for meta-analysis were limited by heterogeneity. No study found a difference in long-term pain severity between trial arms, with the exception of one trial which found home-based functional exercises aimed at managing kinesiophobia resulted in lower pain severity scores at 12 months postoperatively compared with advice to stay active.

CONCLUSION

This systematic review and narrative synthesis found no evidence that one type of physiotherapy intervention is more effective than another at reducing the severity of chronic pain after TKR. Further research is needed to evaluate non-physiotherapy interventions, including the provision of care as part of a stratified and multidisciplinary care package.

PROSPERO REGISTRATION NUMBER

CRD42017041382.

Comparison of a pressure-sensing sheath and radial arterial line for intraoperative blood pressure monitoring in neurointerventional procedures

Purpose

The efficiency of neuroendovascular procedures may partly depend on the time devoted to placement of a radial arterial line (RAL) for intraoperative blood pressure monitoring. An alternative approach is to use a pressure-sensing sheath (PSS) that serves to provide invasive blood pressure monitoring without requiring a separate procedure for placement. We compared the use of a RAL versus PSS and assessed procedure time, anesthetist and patient satisfaction, and cost.

Methods

We performed a single-center, prospective, blockwise, comparative trial of procedure start time using traditional RAL placement versus the EndoPhys PSS for invasive blood pressure monitoring. Endpoints included time from room arrival to groin puncture, patient and anesthetist satisfaction ratings, and costs associated with RAL placement.

Results

Twenty patients were enrolled in the PSS+RAL arm and 20 in the PSS-alone arm. Mean time from arrival in the room until groin puncture was 61.9±14.0 min in the RAL group and 51.2±10.8 min in the PSS-alone group (P=0.01; difference=10.7 min). Patients in the PSS-alone group reported less pain than those in the RAL group. Furthermore, anesthetists reported accurate blood pressure in the PSS group. The average cost estimate of RAL placement was US$774.70, with a range of US$743 to US$1171.

Conclusions

Placement of a RAL at the start of the neuroendovascular procedures resulted in increased delays to procedure start time and more patient-reported pain compared with the PSS, which may offer a more efficient means of blood pressure monitoring for neurointerventional procedures.

Clinical trial registration

NCT03239847.

Development of a complex intervention for people with chronic pain after knee replacement: the STAR care pathway

BACKGROUND

Approximately 20% of people who have total knee replacement experience chronic pain afterwards, but there is little evidence about effective interventions for managing this type of pain. This article describes the systematic development and refinement of a complex intervention for people with chronic pain after knee replacement. The intervention is a care pathway involving an assessment clinic and onward referral, with telephone follow-up as required. In the design of this multistage study, we chose to focus on ensuring that the intervention was deliverable, implementable and acceptable.

METHODS

In line with the UK Medical Research Council's recommendations for comprehensive development of complex interventions, multiple phases of work were undertaken. Following on from initial development work to design the intervention, the draft intervention content was refined through consensus questionnaires with 22 health professionals and discussion at meetings with 18 healthcare professionals. Testing of intervention delivery and acceptability to patients was undertaken by two health professionals delivering the assessment clinic to ten patients. Views about future implementation within the context of a randomised trial were evaluated through a questionnaire based on the Normalisation Measure Development (NoMAD) instrument with ten health professional stakeholders.

RESULTS

Consensus work with health professionals ensured the components of the intervention were appropriate and informed a number of substantive changes to improve the intervention. Testing of intervention delivery identified a number of logistical issues that were then addressed in the development of a comprehensive intervention training manual. Engagement with stakeholders indicated that the intervention could be successfully implemented in a clinical setting for evaluation in a randomised trial.

CONCLUSIONS

This work has informed the development and refinement of a complex intervention for people with chronic pain after knee replacement. The next stage is to evaluate the clinical and cost-effectiveness of the STAR care pathway in a multicentre randomised trial.