Chronic pain after total knee arthroplasty

Multidimensional pain assessment and opioid use after total knee arthroplasty: continuous vs single-injection regional vs systemic analgesia

Introduction

Effective pain management after total knee arthroplasty (TKA) is essential for recovery. Continuous peripheral nerve blocks (PNBc) are often believed to provide superior pain relief compared with single-injection peripheral nerve blocks (PNBs). However, multidimensional pain-related patient-reported outcomes (PROs) have not been extensively studied.

Objective

Based on registry data, this study compared pain intensities summarized as a pain composite score (PCS) and postoperative opioid use between PNBc and PNBs nerve blocks in patients undergoing TKA, and evaluated additional PROs.

Methods

Data from 4,328 adults undergoing TKA enrolled in the PAIN OUT registry (ClinicalTrials.gov NCT02083835) were analyzed. Patients were categorized into general anesthesia (GA) or spinal anesthesia (SA), with subgroups general anesthesia only (GA-o) or spinal anesthesia only (SA-o), and combinations with single-injection PNB (GA&PNBs and SA&PNBs) or continuous PNB via catheter (GA&PNBc and SA&PNBc). The primary end point was PCS, summarizing pain intensities and time in severe pain during the first 24 hours. Secondary end points included opioid use and additional PROs.

Results

The use of GA&PNBc was associated with a higher PCS (+0.5 [0.0-0.9], P = 0.035) compared with GA&PNBs, while PCS was similar between SA&PNBs and SA&PNBc. Opioid use was more frequent in GA&PNBc (+20.3%) and SA&PNBc (+50.8%) compared with the respective PNBs groups (P < 0.001). Patient-reported outcomes were higher in PNBc groups (median score 3.2 vs 2.7-2.9 in other groups; P < 0.001).

Conclusion

Continuous PNBc showed no clear advantage over PNBs in pain relief, opioid use, or further PROs. Future research should incorporate comprehensive PROs to better evaluate analgesic techniques in TKA.

Tenderness over the Pes anserinus and Gerdy's tubercle before and after total knee arthroplasty

Objectives

Several patients experience chronic pain after total knee arthroplasty (TKA), with the source of postoperative pain attributed to intra- and extra-articular factors. This study focused on the proximal tibia with either the Pes anserinus (PA) or around Gerdy's tubercle (GT) as the most common site of extra-articular pain.

Methods

This prospective study included 270 patients (360 knees) with advanced varus osteoarthritis (OA) of the knee scheduled for primary TKA and the patient population comprised 289 women and 71 men with a mean age of 74.7 ± 7.4 years. Operative procedure was performed by a single surgeon. This study investigated the prevalence of PA and GT tenderness over the knee before and after TKA and the association between this tenderness and several factors.

Results

Before TKA, 66.1 % of the patients experienced PA tenderness, whereas 33.1 % experienced GT tenderness. One year after TKA, 49.7 % of the patients experienced PA tenderness, whereas 19.7 % experienced GT tenderness. More than half of the postoperative symptoms in the extra-articular region remained from the preoperative period. Female sex and high body mass index were associated with preoperative and postoperative tenderness of the PA and postoperative tenderness of GT. Postoperative PA and GT tenderness is associated with lower Knee Scoring System 2011 subjective and functional activity scores.

Conclusions

The extra-articular region (PA or GT) is associated with postoperative joint pain and function after knee arthroplasty, and more than half of the postoperative symptoms in the extra-articular region remained from the preoperative period.

Management of post-arthroplasty pain: a narrative review of emerging interventional treatments

Total joint arthroplasties are one of the most common orthopedic procedures with over 1 million total hip and knee arthroplasties performed annually. While the majority of patients experience favorable long-term outcomes, a significant number of patients continue to report persistent pain more than 3 months post-arthroplasty that is unresponsive to conservative treatment. Although current treatment options may seem limited, there are a variety of innovative procedures for the management of post-arthroplasty pain with the overall goal of reducing pain and restoring function. In this review, we outline the work-up for persistent post-arthroplasty pain and provide a review of the literature on interventional treatment modalities consisting of intra-articular steroids, radiofrequency ablation, and neuromodulation for the management of chronic post-arthroplasty pain in the hip, knee, ankle, and shoulder.

The causal role of brain circuits in osteoarthritis pain

Osteoarthritis (OA) is a leading cause of chronic pain worldwide, resulting in substantial disability and placing a substantial burden on patients and society. The hallmark symptom of OA is joint pain. Despite extensive research, new treatments for OA pain remain limited, partly owing to a lack of understanding of underlying pain mechanisms. For a long time, OA pain was seen as a reflection of nociceptive activity at the joint level, and the brain has been viewed as a passive recipient of such information. In this Review, we challenge these concepts and discuss how, over time, the activation of peripheral nociceptors leads to adaptations in the brain that dictate the properties and experience of OA pain. These adaptations are further influenced by the inherent properties of the brain. We review general concepts that distinguish pain from nociception, present evidence on the incongruity between joint injury and experience of OA pain, and review brain circuits that are crucial in the perception of OA pain. Finally, we propose a model that integrates nociception, spinal-cord mechanisms, and central nervous system dynamics, each contributing uniquely to pain perception. This framework has the potential to inform the development of personalized treatment strategies.

Genicular Nerve Ultrasound-Guided Cryoanalgesia for the Treatment of Chronic Knee Joint Pain: An Observational Retrospective Study

INTRODUCTION

Chronic knee pain caused by osteoarthritis (OA) is a prevalent source of disability in the adult population. Total knee arthroplasty (TKA) is an effective surgical treatment for advanced disease, but many patients continue to suffer from chronic post-surgical pain (CPSP). In recent years, minimally invasive techniques targeting peripheral nerves have been explored. Cryoanalgesia of the genicular nerves (GNCryo) is one such intervention that disrupts sensory input by applying extremely low temperatures to the target nerves, potentially leading to sustained pain relief without the need for neurodestructive heat lesions. This study aims to evaluate the effectiveness of ultrasound-guided GNCryo in patients with chronic knee pain due to primary OA or CPSP after TKA.

METHODS

This retrospective, single-center study included 90 patients who underwent GNCryo between September 2021 and February 2023. Inclusion criteria were patients over 18 years of age, symptomatic knee OA or CPSP after TKA, and a positive response (≥ 50% pain relief) to diagnostic genicular nerve blocks. Ultrasound guidance was used to optimize needle placement and reduce complications. Clinical outcomes were assessed at baseline and at 1, 3, 6, and 9 months post-procedure. Outcome measures included the Visual Analog Scale (VAS, 0-10) for pain intensity, the Western Ontario and McMaster Universities Arthritis Index (WOMAC, 0-100) for assessing pain, stiffness, and physical function related to OA, the Douleur Neuropathique en 4 Questions (DN4, 0-10) for neuropathic pain, and the EuroQol 5-Dimension (EQ-5D, 0-100) for quality of life.

RESULTS

Ninety patients completed the 9 months follow-up. The median VAS score decreased from 7.0 (6.0, 8.0) at baseline to 4.0 (3.0, 5.0) at 1 month, remained at 4.0 (3.0, 5.0) at 3 months, and increased slightly to 5.0 (4.0, 5.0) at 6 months and 5.0 (4.0, 6.0) at 9 months, yet pain relief remained lower than baseline. WOMAC scores decreased from 65 (55, 71) at baseline to 35 (30, 40) at 1 month and 35 (30, 40) at 3 months, increased to 40 (35, 50) at 6 months and 55 (45, 65) at 9 months. DN4 scores decreased from 7 (5, 8) at baseline to 4 (3, 4) at 1 month and 3 (2, 4) at 3 months, increased to 3.5 (3, 5) at 6 months and 5 (4, 6) at 9 months, yet remained lower than baseline. EQ-5D scores increased from 64.5 (47, 84) at baseline to 42 (32, 58) at 1 month, 43.5 (31, 59) at 3 months, 45.5 (35, 60) at 6 months, and 52 (41, 72) at 9 months.

CONCLUSIONS

Ultrasound-guided GNCryo is a promising minimally invasive treatment for chronic knee pain, providing pain relief and improved quality of life for up to 9 months. Although some outcomes showed a trend toward baseline over time, pain relief remained lower than baseline, consistent with potential nerve regeneration or recovery. Larger prospective, controlled trials are necessary to confirm these findings and to refine patient selection and technique optimization.

Effects of Integrating Pain Coping Strategies into Occupational Therapy After Total Knee Arthroplasty: A Parallel Mixed-Method Study

Background/Objectives: This study aimed to evaluate whether integrating coping strategies into occupational therapy (OT) enhances functional recovery and psychological adaptation after total knee arthroplasty (TKA). Methods: Twenty-eight patients who underwent TKA were equally assigned to an intervention and control group. Both groups received standard goal-oriented OT, while only the intervention group underwent structured training in pain coping strategies using the "Coping List". Treatment effects were assessed using Canadian Occupational Performance Measure (COPM), pain, anxiety, depression, and pain-related disability scores. Results: A total of 210 coping strategies were identified, with the intervention group adopting an average of 15.1 additional strategies per patient. Strategies were categorized into six domains: physical, psychological and cognitive, social support, relaxation, daily activities, and medication management. The intervention group showed significantly greater improvements in COPM performance scores (7.6 ± 1.7 vs. 5.5 ± 2.6; p = 0.048) and COPM satisfaction scores (7.9 ± 2.0 vs. 5.6 ± 2.8; p = 0.049) compared to the control group. Conclusions: The findings suggest that individualized coping strategies integrated with physical rehabilitation can help patients achieve postoperative goals, enhance recovery, and improve overall well-being. Incorporating such strategies into OT appears to be effective in early-postoperative rehabilitation. Clinical trial number: This study's clinical trial registration information is available online at UMIN (UMIN000050536).

Prevalence and rehabilitation factors associated with chronic pain after total knee arthroplasty in Jordan

PURPOSE

Total knee arthroplasty (TKA) is a highly effective treatment for osteoarthritis patients unresponsive to conservative therapies. Chronic postsurgical pain (CPSP) following TKA is understudied, with approximately 20% of patients reporting chronic pain. This cross-sectional study conducted in Jordan aims to (1) determine the prevalence of chronic knee pain after TKA in the Jordanian population and (2) identify associations between demographics and rehabilitation factors with chronic pain.

METHODS

Data were collected from 90 Jordanian patients post-TKA. Demographics (age, gender, BMI, and smoking) and rehabilitation factors (pre-operative sessions, post-operative sessions, and duration) were recorded. Statistical analyses included descriptive statistics and 95% confidence intervals. Independent t-tests and Chi-square analyses were used to determine the differences between those with and without chronic pain. Pearson correlations were used to determine the association between demographic and rehabilitation factors with the prevalence of chronic pain.

RESULTS

Ninety patients were included in the study with an average age of 60.3 ± 10.1 years. The prevalence of chronic post-TKA pain in Jordan was 57.8% (52/90), (95% CI: 46.9-68%). No significant differences were found in demographics and pre-operative rehabilitation. Chronic pain was significantly associated with post-operative rehabilitation sessions and duration (r =.349, p =.001) (r =.342, p =.001, respectively. Patients with chronic pain received fewer post-operative rehabilitation sessions (P <.001) and had shorter rehabilitation durations (P <.001) compared to patients without chronic pain.

CONCLUSION

Chronic pain after TKA is highly prevalent in Jordan (57.8%), with reduced rehabilitation engagement strongly linked to its occurrence. Optimizing post-operative rehabilitation protocols may mitigate CPSP risk among Jordanian TKA patients.

Accelerated intermittent theta burst transcranial magnetic stimulation of the dorsolateral prefrontal cortex for chronic knee osteoarthritis pain

OBJECTIVE

This study assessed feasibility, safety, and tolerability of accelerated intermittent theta burst stimulation (aiTBS) with effective connectivity-guidance targeting the left dorsolateral prefrontal cortex (lDLPFC) from the right anterior insular (rAI) in chronic knee osteoarthritis pain.

METHODS

The BoostCPM clinical trial (ISRCTN15404076) was a randomized, sham-controlled, single-blind, parallel-group pilot study in patients with mild-moderate chronic pain. Participants were assigned 2:1 (active: sham) aiTBS for 4 consecutive days (totaling 36,000 pulses) at a daily dose of 9000 pulses (5 sessions of 1800 pulses). Primary outcomes included safety, tolerability, pain-related and affective outcomes, and quantitative sensory testing.

RESULTS

45 participants received active (n = 33) or sham (n = 12) aiTBS. No serious adverse events were recorded, and protocol adherence (tolerability) was 80.6 % and 100 % for active and sham. Follow-up response rate was 78.1 % and overall acceptance/satisfaction was 89 %. Pain relief was observed immediately after treatment and lasted 16 weeks with clinically meaningful reduction of pain burden, but no differences between groups.

CONCLUSIONS

aiTBS with rAI-connected lDLPFC targeting is a safe, well tolerated, feasible, and acceptable intervention in chronic pain patients. However, we found no additional improvements compared to sham.

SIGNIFICANCE

Further studies of aiTBS and lDLPFC targeting for pain relief are warranted.

Chronic pain at 1-year following knee arthroplasty is associated with a worse joint-specific function and health-related quality of life

PURPOSE

The purpose of this study was to identify independent variables associated with chronic pain (CP) at 1 year following knee arthroplasty (KA) and whether this influenced functional outcomes.

METHODS

This retrospective study was conducted over a 2-year period and included 2588 patients with completed Oxford knee score (OKS) and EuroQol (EQ)-five domains (5D) preoperatively and at 1 and 2 years postoperatively. The OKS pain component score was used to define patients with CP (≤14 points). The mean age was 70.0 (range 34-94) years and there were 1553 (60.0%) females.

RESULTS

There were 322 (12.4%) patients with CP at 1 year. A worse preoperative EQ-5D (p = 0.025), EQ-visual analogue scale (VAS) (p = 0.005) and OKS questions relating to washing (p = 0.010), limping (p = 0.007), kneeling (p = 0.003) and night pain (p = 0.004) were independently associated with risk of CP. However, the preoperative OKS (area under the curve [AUC]: 72.0, p < 0.001) and EQ-5D score (AUC: 70.1, p < 0.001) were the most reliable predictors, with threshold values of <18-points and <0.300 being predictive of CP, respectively. Of those with CP at 1 year, 231 were followed up at 2 years, of which 92 (39.8%) had resolution of their CP. A worse response to OKS question 11 (ability to shop) and EQ-5D (p = 0.028) at 1 year was independently associated with persistent CP. Patients with CP had significantly (p < 0.001) worse OKS, EQ-5D and EQ-VAS at 1 year compared to those without. However, for those that had resolution of their CP at 2 years, their outcomes were clinically equal to those that did not have CP at 1 year.

CONCLUSION

One in eight patients had CP at 1 year following surgery, which was associated with clinically worse knee-specific outcomes and quality of life. However, by 2 years, two in five patients had resolution of their CP and had functional outcomes clinically equal to those without CP at 1 year. The risk factors identified could be used to inform patients of their risk for CP and the potential for resolution.

LEVEL OF EVIDENCE

Level III retrospective study.

Chronic knee pain while awaiting arthroplasty is associated with worsening joint-specific function, health-related quality of life and personal wellbeing, and increased use of opioid analgesia

Aims

To assess whether chronic knee pain (CKP) influenced health-related quality of life (HRQoL), knee-specific health, wellbeing, and use of opioid analgesia, and identify variables associated with CKP in patients awaiting knee arthroplasty.

Methods

This study included 217 patients (mean age 69.7 years (SD 8.7), 116 female (53%)) who completed questionnaires that included the EuroQol five-dimension questionnaire (EQ-5D) and EuroQol-visual analogue scale (EQ-VAS), Oxford Knee Score (OKS), and wellbeing assessments at six and 12 months after being listed for surgery. Analgesia use at 12 months was also recorded. CKP was defined using the OKS pain score (PS) of ≤ 14 points at 12 months.

Results

At 12 months, 169 patients (77.9%) had CKP. Compared with those without CKP, those with CKP had clinically meaningfully worse HRQoL and knee-specific health at 12 months and were more likely to have a health state worse than death (odds ratio (OR) 29.7, 95% CI 4.0 to 220.2; p < 0.001). The CKP group were more likely to use weak (OR 3.03, 95% CI 1.65 to 7.96; p = 0.001) and strong (OR 11.8, 95% CI 1.58 to 88.88; p = 0.001) opioids for analgesia. The CKP group had worse overall wellbeing with significantly (p < 0.001) lower satisfaction with life, life being worthwhile and happiness, and increased anxiety. The CKP group had a significant (p < 0.001) deterioration in their OKS, OKS-PS, EQ-5D, and EQ-VAS from six to 12 months, which was not observed in the group without CKP. A worse OKS-PS at six months was independently associated with an increased risk of CKP, and a threshold value of < 13 (sensitivity 91.7%, specificity 94.7%) was an excellent discriminator (area under the curve 96.9, 95% CI 94.2 to 99.6; p < 0.001).

Conclusion

Four in five patients had CKP after waiting 12 months, which was associated with deteriorations in HRQoL and knee health, worse wellbeing, and increased opioid analgesia use. The OKS-PS at six months could be used to identify patients at risk of CKP after 12 months of waiting.

Consensus statement on problematic knee replacement and revision knee replacement: A collaboration between EKS and BASK

BACKGROUND

Up to 20% of primary total knee arthroplasty (TKA) patients are not satisfied with their outcome. Both the analysis of these patients and revision surgery can be complex, expensive and outcomes can vary widely.

AIM

The aim of this study was to deliver consensus recommendations regarding outpatient analysis, surgical treatment and arrangement of clinical services concerning patients with a problematic TKA or revision knee replacement (RTKA).

METHODS

Members of BASK and EKS were invited to attend a joint meeting in London, UK (December 2019). A formal consensus process was undertaken at the meeting incorporating a multiple round Delphi exercise, with group discussion of areas of agreement and disagreement between rounds. Eighty delegates attended the meeting and five consensus statements were considered, with a threshold level of 80% agreement required as the definition consensus. A further consensus meeting of EKS members in Kitzbuhl, Austria (January 2023) followed similar methodology and considered a further four statements on this topic.

RESULTS

From the first meeting, 5 consensus statements with accompanying supporting evidence and text were agreed. 1) In suspected infection, a recognised diagnostic pathway and definition should be used (e.g. MSIS, ICM, EBJIS) and documented; 2) Revision of an infected TKA should be treated in units with a multidisciplinary team; 3) Initial investigation of a problematic TKA should include a minimum of: clinical investigation, X-Rays and blood tests, with further discussion with the MDT if required; 4) Units providing RTKA should have surgeons with evidence of specific training or experience, and on-going minimum unit numbers; 5) National Orthopaedic/Knee Societies should develop a strategy on Revision TKA provision taking into account: workforce, revision burden, location, hospital infrastructure. From the second meeting a further 4 consensus statements were agreed. Two statements were agreed text content answering the questions: 1) What should be included in the basic diagnostic workup of a painful TKA? and 2) Which are the key factors for surgeons to consider before offering the patient revision surgery? The two other agreed statements are: 3) Pre-operative diagnosis is related to outcome in RTKA and 4) RTKA for pain, without a surgically treatable diagnosis, is unpredictable.

CONCLUSIONS

The agreed joint BASK-EKS consensus statements and the EKS consensus statements on the assessment of problematic RTKA are recommended as the contemporary basis of optimal care for these patients and should inform future training and service developments.

Genicular Nerve Radiofrequency Ablation for Chronic Knee Joint Pain Using a V-Shaped Active Tip Needle: A Single-Center Retrospective Observational Study

Background

Chronic knee pain from osteoarthritis (OA) affects a significant proportion of adults over 40. Total knee arthroplasty (TKA) remains the standard for advanced OA, yet up to 20% of patients experience chronic postsurgical pain (CPSP). Genicular nerve radiofrequency ablation (GNRFA) can alleviate pain in those unresponsive to conservative treatments or TKA. However, anatomical variability of the genicular nerves may limit treatment durability. This retrospective, single-center observational study investigated whether using a novel V-shaped active tip needle-which creates larger lesions-could improve outcomes.

Methods

Fifty patients with symptomatic knee OA or CPSP, who had a ≥50% reduction in pain after diagnostic genicular nerve blocks, underwent GNRFA with a V-shaped active tip needle between September 2020 and January 2022. Pain and function were assessed using the visual analogue scale (VAS) at rest and during movement, Western Ontario and McMaster Universities Arthritis Index (WOMAC), Douleur Neuropathique en 4 Questions (DN4), and EuroQol-5 Dimensions (EQ-5D) at baseline and 1, 3, 6, and 9 months post-procedure.

Results

By 6 months, 64% of patients showed ≥50% reduction in VAS pain scores, sustained at 9 months (p<0.0001). Median WOMAC scores improved from 62.0 at baseline to 40.0 at 6 months (p<0.0001). DN4 scores declined from a median of 4.0 at baseline to 2.0 at 6 months and 1.0 at 9 months (p<0.001). EQ-5D scores demonstrated significant enhancement in quality of life (p<0.01). Pain intensity differences at rest and during movement remained substantially improved at 9 months (p<0.0001).

Conclusion

GNRFA using a V-shaped active tip needle is a promising intervention for chronic knee pain, offering significant and sustained pain relief and functional improvement. Larger lesions created by the novel needle may overcome anatomical challenges, though further randomized studies are warranted to validate efficacy and safety.

Factors Associated With Postoperative Pain Trajectory, Nausea, and Vomiting After Total Knee Arthroplasty: A Retrospective Study

OBJECTIVES

Postoperative pain, nausea, and vomiting (PONV) adversely affect postoperative rehabilitation after total knee arthroplasty (TKA). We aimed to identify factors associated with postoperative pain trajectory and PONV and evaluated the effects of different analgesic modalities.

METHODS

We retrospectively reviewed patients undergoing unilateral primary TKA from 2017 to 2022. Patients received either general or spinal anesthesia. Patient-controlled analgesia (PCA) included patient-controlled epidural analgesia (PCEA) and intravenous analgesia (PCIA). Outcome variables included maximal pain intensity at certain times (before surgery, and 24 h and 48 h after surgery); and incidence of PONV. A generalized estimating equation was used to determine the correlation between PCA usage and longitudinal pain score at 48 hours follow-up after surgery. Multivariable logistic regression analyses were used to evaluate PONV after adjusting for potential confounders.

RESULTS

In total, 2510 patients were included in the analyses. Patients without PCA intervention and with higher BMI reported greater acute postoperative pain. Furthermore, women and lower BMI were associated with higher rates of PONV. After adjusting for confounding factors, the PCEA group had a lower pain score than both the no PCA group (β estimate =-0.443, 95% CI= [-0.561 to -0.324], P <0.001) and the PCIA group (mean difference=-0.227, 95% CI = [-0.328 to -0.126], P <0.001).

CONCLUSION

General anesthesia and PCA had no effect on the PONV incidence after TKA. Greater BMI correlated with higher pain scores but a lower likelihood of PONV. Epidural PCA provided superior acute postoperative analgesia without increasing the incidence of PONV.

Clinical Predictors of the Forgotten Joint Score 12 in Total Knee Arthroplasty

BACKGROUND

Patient-reported outcomes have become a key criterion for determining patient satisfaction following orthopedic procedures like total knee arthroplasty (TKA). The Forgotten Joint Score 12 (FJS-12) is designed to evaluate if a patient is aware of their replaced joint. Little literature exists surrounding the predictive power of other metrics on the FJS-12. In this paper, differences in these clinical metrics were assessed between groups of patients who scored above the FJS-12 cutoff and those who did not after TKA.

METHODS

Patients who underwent primary elective TKA and answered all required patient-reported outcomes during the designated study period were included. Using an established cutoff of 33.3, patients were put in a "Forgotten Joint Group" or a "Remembered Joint Group." This study included 672 patients who fit the criteria. Of these, 508 (76%) forgot their joints and 164 (24%) remembered their joints at 12 months. Differences in clinical metrics between the two groups were assessed for significance using univariate analyses (t-test, Chi-square, Fisher's exact). Receiver operating characteristic curve analysis was then used to determine the predictive value of metrics that showed these significant differences.

RESULTS

Early results from the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and Numeric Pain Scale were strongly correlative of the twelve-month FJS-12 score, rather than patient demographics. Patients who scored above 65.1 or 72.1 on the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement three and six months after surgery, respectively, or below a 3 on the Numeric Pain Scale three and/or six months after surgery were also favored to forget their replaced joint at twelve months.

CONCLUSIONS

Identifying predictors of the FJS-12 allows for the recognition of at-risk patients before the 12-month time point, facilitating earlier intervention and improving care after surgery. The scope of this analysis may be broadened in the future to include other arthroplasty procedures, such as for the hip or shoulder.

Preoperative peripheral nerve blocks are not independently associated with improved functional outcome, patient satisfaction, or risk of chronic pain at one year following knee arthroplasty

Aims

Control of acute pain following knee arthroplasty (KA) with a perioperative peripheral nerve block (PNB) may improve functional outcomes and reduce the risk of chronic postoperative knee pain (CPKP). The aims of this study were to assess whether a PNB influences patient-reported outcomes and risk of CPKP at one year following KA.

Methods

A retrospective study was conducted over a two-year period and included 3,338 patients who underwent KA, of whom 1,434 (43.0%) had a lower limb PNB. A total of 2,588 patients (77.6%) completed and returned their one-year follow-up questionnaire. The Oxford Knee Score (OKS) and pain component (OKS-PS), EuroQol five-dimension questionnaire (EQ-5D), and EQ-visual analogue scale (VAS) were collected preoperatively and at one year postoperatively. Patient satisfaction was also recorded at one year. The OKS-PS was used to define CPKP at one year.

Results

The PNB group were younger (mean difference (MD) 0.7 years, 95% CI 0.0 to 1.3; p = 0.039), had a worse OKS (MD 0.7, 95% CI 0.1 to 1.3; p = 0.027), and were more likely to have had a spinal anaesthesia relative to a general anaesthetic (odds ratio 4.2, 95% CI 3.23 to 5.45; p < 0.001). When adjusting for confounding factors, patients in the PNB group had a significantly reduced improvement in their OKS (MD -0.9, 95% CI -1.6 to -0.1; p = 0.022), which may not be clinically meaningful. There were no significant differences in the OKS-PS (p = 0.068), EQ-5D (p = 0.313), or EQ-VAS (0.855) between the groups when adjusting for confounding factors. When adjusting for confounding factors using binary regression analysis, there were no differences in patient satisfaction (p = 0.132) or in the risk of CPKP (p = 0.794) according to PNB group.

Conclusion

PNBs were independently associated with worse knee-specific outcomes, but whether these are clinically meaningful is not clear, as the difference was less than the minimal clinically important difference. Furthermore, PNBs were not independently associated with differences in health-related quality of life, patient satisfaction, or risk of CPKP.

Postoperative Complications and Readmission Rates in Robotic-Assisted Versus Manual Total Knee Arthroplasty: Large, Propensity Score-Matched Patient Cohorts

INTRODUCTION

There is a paucity of research comparing postoperative complication rates between manual total knee arthroplasty (M-TKA) and robotic-assisted total knee arthroplasty (RA-TKA). This study aims to compare 90-day postoperative complication, readmission, and emergency department rates between RA-TKA and M-TKA.

METHODS

A retrospective review of a multihospital database identified patients who underwent TKA between January 2016 and May 2023. Surgeons who used the robotic-assisted surgery technique in <10% or >90% of their cases annually were excluded. This resulted in 15,999 cases (8,853 RA-TKAs; 7,146 M-TKAs) from 282 surgeons. RA-TKA and M-TKA cohorts were one-to-one matched based on patient sex, age, body mass index, hospital setting, surgeon experience, primary payer, and anesthesia type. Each cohort consisted of 7,146 patients (N = 14,292). 90-day revisits, specifically readmissions, readmissions with >23 hours of observation, and ED visit rates were compared between cohorts. Complications were classified according to the Clinical Classification Software schema and compared between cohorts. Mann-Whitney U, chi-squared, and Fisher exact tests, along with Bonferroni correction, were used to statistically compare cohorts.

RESULTS

All-cause 90-day readmission rates were 2.4% for RA-TKA and 2.6% for M-TKA ( P = 0.36). RA-TKA had fewer revisits (RA-TKA: 7.8%; M-TKA: 8.8%, P = 0.027) and rates of readmission with >23 hours of observation (RA-TKA: 1.4%; M-TKA: 2.0%, P = 0.003). RA-TKA had fewer hospital revisits due to joint stiffness (RA-TKA: 17 revisits; M-TKA: 42 revisits, P = 0.002) and chronic pain (RA-TKA: 1 revisit; M-TKA: 8 revisits, P = 0.039). Fewer readmissions were observed for acute injuries (lower extremity muscle/tendon strains) in the RA-TKA cohort (RA-TKA: 1; M-TKA: 9, P = 0.021). RA-TKA had fewer ED visits due to hematomas (RA-TKA: 0 visits; M-TKA: 7 visits, P = 0.016).

CONCLUSION

In this retrospective matched cohort analysis, RA-TKA was associated with markedly fewer revisits and readmissions with >23 hours of observation compared with M-TKA. No differences in all-cause 90-day readmission were observed between cohorts.

LEVEL OF EVIDENCE

Level III.

STUDY DESIGN

Retrospective review.

The association between screened psychological risk for disability and appropriateness of orthopedic surgery in patients with musculoskeletal disorders - data from a Swedish RCT in primary care 2009-2011

INTRODUCTION

To understand, diagnose and treat patients with musculoskeletal disorders, psychological risk factors should be assessed, and the association between psychological risk for disability and appropriateness of orthopedic surgery should be investigated.

PURPOSE

To investigate the association between screened psychological risk for disability and appropriateness of orthopedic surgery, and to examine a physiotherapist's ability to assess risk for disability in patients referred for orthopedic consultation.

METHOD

Patients (n = 192) were assessed by a physiotherapist or an orthopedic surgeon to determine the need for surgery. The Pain Belief Screening Instrument (PBSI) was used to screen for psychological risk. The physiotherapist assessed psychological risk for disability based on yellow flags. Association between PBSI risk profile and appropriateness of orthopedic surgery was analyzed using logistic regression. Sensitivity and specificity of the physiotherapist's assessment of risk was calculated using a binary classification model.

RESULTS

Orthopedic surgery was 2.28 times more likely to be considered an appropriate intervention for patients with a high PBSI risk profile (95% CI 1.09;4.78). The physiotherapist's risk assessment correctly identified 88% of those at low risk (specificity) and 32% of those at high risk for disability (sensitivity).

CONCLUSION

The findings suggest that orthopedic surgery is likely to be considered appropriate for patients with a high PBSI risk profile. The high specificity of the physiotherapist's assessment implies good awareness of psychological factors. The low sensitivity suggests a need for using a screening tool such as the PBSI, to guide management decisions.Trial registration: Clinical Trials NCT02265172, retrospectively registered June 10, 2014.

Preoperative glycaemic control, number of pain locations, structural knee damage, self-reported central sensitisation, satisfaction and personal control are predictive of 1-year postoperative pain, and change in pain from pre- to 1-year posttotal knee arthroplasty

PURPOSE

The aim of this study was to identify preoperative predictors for 1-year posttotal knee arthroplasty (TKA) pain and pre- to post-TKA pain difference in knee osteoarthritis (KOA) patients.

METHODS

From March 2018 to July 2023, this prospective longitudinal cohort study enrolled KOA patients awaiting TKA from four hospitals in Belgium and the Netherlands. Different biopsychosocial predictors were assessed preoperatively by questionnaires and physical examinations (input variables). The Knee injury and Osteoarthritis Outcome Score (KOOS) subscale pain was used to measure pain intensity. The absolute KOOS subscale pain score 1-year post-TKA and the difference score (ΔKOOS = 1-year postoperative - preoperative) were used as primary outcome measures (output variables). Two multivariable linear regression analyses were performed.

RESULTS

Two hundred and twenty-three participants were included after multiple imputation. Worse absolute KOOS subscale pain scores 1-year post-TKA and negative or closer to zero ΔKOOS subscale pain scores were predicted by self-reported central sensitisation, lower KOA grade and preoperative satisfaction, and higher glycated haemoglobin, number of pain locations and personal control (adjusted R2 = 0.25). Additional predictors of negative or closer to zero ΔKOOS subscale pain scores were being self-employed, higher preoperative pain and function (adjusted R2 = 0.37).

CONCLUSION

This study reports different biopsychosocial predictors for both outcomes that have filtered out other potential predictors and provide value for future studies on developing risk assessment tools for the prediction of chronic TKA pain.

PROTOCOL REGISTRATION

The protocol is registered at clinicaltrials.gov (NCT05380648) on 13 May 2022.

LEVEL OF EVIDENCE

Level II.

Perioperative intravenous dexamethasone did not reduce the severity of persistent postsurgical pain after total knee arthroplasty: a prospective, randomized, double-blind, placebo-controlled trial

BACKGROUND

Even with the great advancements in recent years in total knee arthroplasty (TKA), some patients continue to have persistent postsurgical pain (PPSP). The advantages of systemic corticosteroids in the perioperative context have been further supported by previously published trials. However, the impact of dexamethasone on the intensity of post-TKA PPSP is still unclear. We aimed to investigate its effect on the degree of PPSP and compare that with a placebo.

METHODS

In this randomized, double-blind, placebo-controlled study, 48 patients undergoing unilateral TKA were given intravenous dexamethasone 10 mg or saline just before spinal anesthesia was induced, and they also received two additional doses of dexamethasone 10 mg or saline 24 and 48 h after surgery. A standardized, multimodal analgesic regimen was administered to each patient. The modified WOMAC pain scores at 12 weeks postoperative were the main outcome. The secondary outcomes included pain during a walk of five meters, pain during active knee flexion at 45 degrees, maximum pain at rest during the previous 24 h, nausea visual analogue scale values, and use of rescue opioid and antiemetic medications.

RESULTS

There was no difference in modified WOMAC pain scores 12 weeks after surgery between patients who received and did not receive perioperative dexamethasone. At 24, 30, 48, 54, and 72 h following surgery, the dexamethasone group experienced considerably less pain during a five-meter walk and during 45 degrees active knee flexion (p < 0.01). At postoperative 0-24, 24-48, and 48-72 h, the dexamethasone group experienced less maximal pain at rest (p < 0.01). The dexamethasone group also had less visual analogue scale scores for nausea at 6, 24, 30, 48, and 54 h after surgery (p < 0.02). During the first 0-24 and 24-48 h, the dexamethasone group consumed fewer opioids and antiemetic medications (p < 0.01). All patients showed no signs of wound complications.

CONCLUSIONS

When compared to a placebo at 12 weeks after TKA, intravenous dexamethasone did not reduce PPSP. Nevertheless, early postoperative pain was relieved by perioperative intravenous dexamethasone, which also decreased the need for opioid and antiemetic medications and decreased postoperative nausea and vomiting.

TRIAL REGISTRATION

NCT02760459.

Uneasiness in interdisciplinary research and the importance of metaphors: A case story on building an interdisciplinary chronic pain research team

Interdisciplinary research is increasingly recognized as a key method to tackle complex societal challenges and stimulate creativity to find innovative solutions. Our key goal when starting our collaboration was to come to innovative ways of treating chronic pain. An ambitious goal that requires out-of-the-box and high-risk-high-gain research. However, interdisciplinary research in practice can be uneasy and will not always be successful. This paper describes a case story focussing on the challenges we faced building an interdisciplinary team. One of the most important lessons is that researchers from different disciplines may think they speak a universal 'language of science', but a thorough understanding of each other's ways of working, research paradigms, methods, and concepts is necessary before they can start working together on solving scientific questions. In fact, if researchers cannot understand each other's language, they cannot expect patients to understand scientific language either. Lastly, for academics to engage with a non-scientific audience and vice-versa, we need to find and create places to meet and find ways to interact effectively. Language is the medium through which all these interactions take place. It is therefore essential that language takes a central place in the process of collaboration across disciplines, interdisciplinary research, patient participation and public engagement. In this case story, we share our experiences in creating a common language, summarized in five steps (1: creating the team; 2: metaphor-forced introduction to disciplines; 3: creating common ground; 4: outreach; 5: integration). Metaphors play an important role in this process. We will demonstrate how we reflectively progressed through these steps while enhancing interdisciplinarity, (scientific) innovation and public engagement. This five-step journey can be used as a process-tool for any other high-risk-high-gain research team seeking to innovate through interdisciplinarity - with the risk of becoming a brilliant failure.

[Observation of analgesic efficacy of liposomal bupivacaine for local infiltration anesthesia in unicompartmental knee arthroplasty: a prospective randomized controlled study]

Objective

A prospective randomized controlled study was conducted to investigate the early postoperative analgesic effectiveness of using liposomal bupivacaine (LB) for local infiltration anesthesia (LIA) in unicompartmental knee arthroplasty (UKA).

Methods

Between January 2024 and July 2024, a total of 80 patients with knee osteoarthritis (KOA) who met the selection criteria were enrolled in the study. Patients were randomly assigned to either the LB group or the "cocktail" group in a 1∶1 ratio using a random number table, with 40 patients in each group. Baseline characteristics, including gender, age, body mass index, operated side, Kellgren-Lawrence grade, and preoperative American Society of Anesthesiologists (ASA) classification, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and knee joint range of motion, showed no significant difference between the two groups ( P>0.05). Both groups received LIA and comprehensive pain management. The surgical duration, incision length, pain-related indicators [resting and activity visual analogue scale (VAS) scores, total dosage of oral morphine, WOMAC scores], knee joint range of motion, first ambulation time after operation, length of hospital stay, and postoperative adverse events.

Results

There was no significant difference between the two groups in surgical duration, incision length, first ambulation time after operation, length of hospital stay, total dosage of oral morphine, and pre-discharge satisfaction with surgery and WOMAC scores ( P>0.05). At 4, 12, and 24 hours after operation, the resting and activity VAS scores in the "cocktail" group were lower than those in the LB group; at 60 and 72 hours postoperatively, the resting VAS scores in the LB group were lower than those in the "cocktail" group, with the activity VAS scores also being lower at 60 hours; all showing significant differences ( P<0.05). There was no significant difference in the above indicators between the two groups at other time points ( P>0.05). On the second postoperative day, the sleep scores of the LB group were significantly higher than those of the "cocktail" group ( P<0.05), while there was no significant difference in sleep scores on the day of surgery and the first postoperative day ( P>0.05). Additionally, the incidence of complications showed no significant difference between the two groups ( P>0.05).

Conclusion

The use of LB for LIA in UKA can provide prolonged postoperative pain relief; however, it does not demonstrate a significant advantage over the "cocktail" method in terms of short-term analgesic effects or reducing opioid consumption and early functional recovery after UKA. Nevertheless, LB may help reduce postoperative sleep disturbances, making it a recommended option for UKA patients with cardiovascular diseases and insomnia or other mental health issues.

A biopsychosocial approach to phenotyping people with knee osteoarthritis awaiting total knee arthroplasty: A secondary cohort analysis

BACKGROUND

Previous research showed chronic post-total knee arthroplasty (TKA) pain in 20% of people with knee osteoarthritis (KOA). Various preoperative biopsychosocial-related factors have been described, but phenotyping people with KOA awaiting TKA based on these factors is still lacking. This could be relevant to understanding differences in TKA surgery responses.

OBJECTIVE

To identify phenotypes in people with KOA awaiting TKA and differences in post-TKA pain based on preoperative biopsychosocial factors.

METHODS

People with KOA awaiting TKA in 4 hospitals in Belgium and the Netherlands were included. A cross-sectional latent profile analysis was conducted on structural, metabolic, functional, pain-related, psychological and social variables. Concurrent validity was tested using 3-step multinomial logistic regression. The difference in one-year post-TKA pain was examined with linear mixed model analysis.

RESULTS

Two hundred and seventeen participants were included in the latent profile analysis with a mean (SD) age of 65.5 (7.7) years, including 109 women. A model with 2 phenotypes differed in 14 out of 21 variables. Participants with phenotype 2 (28%) had a higher body mass index (BMI), higher chance of having less structural damage (KOA grade), lower mean quadriceps strength and physical function (Knee Society Scoring System functional and 30-second chair stand test), higher pain intensity, number of pain locations, and indices of central sensitisation (temporal summation, central sensitisation inventory score, and lower pressure pain thresholds), higher pain catastrophising, anxiety and depression, and higher post-TKA pain intensity compared to phenotype 1 (72%). Concurrent validity was confirmed in 3 out of 4 variables.

CONCLUSIONS

Phenotype 2 (28%) with nociplastic pain characteristics in combination with worse psychological factors, BMI, functional and structural factors, and phenotype 1 (72%) not representing these characteristics were identified. Phenotype 2 had worse pain intensity scores after TKA compared to phenotype 1. Attention to the characteristics of phenotype 2 is warranted concerning post-TKA pain.

DATABASE REGISTRATION

The protocol is registered at ClinicalTrials.gov (NCT05380648).

Navigating the Global Landscape of Exercise Interventions for Knee Osteoarthritis: Exploring Evolving Trends and Emerging Frontiers From a Bibliometric and Visualization Analysis Perspective (2011-2022)

OBJECTIVES

This study utilizes visual analysis methods to retrospectively examine the evolution and trends in exercise interventions for knee osteoarthritis (KOA) research from 2011 to 2022.

DESIGN

Bibliometric and visualization analysis review.

SETTING AND PARTICIPANTS

Using the Web of Science database, the literature search range is from January 1, 2011, to December 31, 2022, with the language specified as English and document type set to Article.

METHODS

Visual analysis was used to analyze literature in the field of exercise interventions for KOA, with KOA and exercise interventions as the key search terms. Visualization maps for countries/regions were created using Tableau and Scimago Graphica software. Institutional, author, and keyword visualization maps were drawn using CiteSpace and VOSviewer software.

RESULTS

In total, 3137 articles were included in the visual analysis. The United States emerged as the leading country in terms of publication volume and contribution. Moreover, developed countries such as the United States, Australia, United Kingdom, and Canada have established close and stable cooperative relationships. The University of Melbourne stood out as the institution with both the highest publication volume and centrality. At the forefront of research output in this field was Bennell K.L. from the University of Melbourne. The journal with the highest co-citation frequency was Osteoarthritis and Cartilage. The keyword clustering map highlighted an evolution in the field of exercise interventions for KOA, emphasizing 8 key research themes spanning knee osteoarthritis, serum cartilage, osteoarthritis initiative, patellofemoral pain, total knee arthroplasty, exercise-induced hypoalgesia, isometric exercise, and anterior cruciate ligament reconstruction. Burst analysis revealed that older adult was the earliest and most prominent keyword, with contemporary topics such as patellofemoral pain, safety, musculoskeletal disorder, and neuromuscular exercise considered as research hotspots and future directions in this field.

CONCLUSIONS AND IMPLICATIONS

The global attention on exercise interventions for KOA research is expanding, emphasizing the importance of strengthened connections among developing countries and collaborative author groups. Recent trends have shifted toward topics such as neuromuscular training, treatment safety, and musculoskeletal disorders, whereas research interest in patellofemoral pain remains unabated. Neuromuscular training for KOA represents the current frontier in this field. Future research should delve into the effects of diverse types of exercise interventions for KOA on neuromuscular injury and recovery, exploring feasibility and safety to formulate personalized exercise plans for patients with KOA.

The effectiveness of vitamin D supplementation in patients with end-stage knee osteoarthritis: Study protocol for a double-blinded, randomized controlled trial

Osteoarthritis (OA) knee is one of the most common chronic degenerative conditions that imposes clinical and economic burdens on individuals and societies worldwide. Previous studies showed vitamin D levels correlated positively with lean muscle mass and grip strength, implying that vitamin D supplementation may improve muscle health in knee OA subjects. This randomized controlled trial (RCT) aims to compare the effects of vitamin D supplementation on knee muscle strength, physical function, pain, and sarcopenia status in patients with end-stage knee OA. Patients and outcome assessors will be blinded to group allocation. Fifty-six end-stage knee OA patients with vitamin D insufficiency fulfilling our inclusion criteria will be invited to participate in this study. Patients will be randomly assigned to take vitamin D supplementation (4,000 IU capsule daily) or placebo for six months. Measurements will be taken at baseline, three and six-month after the commencement of the vitamin D supplement, and 6-month after the interventional period. The primary outcome includes the isometric quadriceps and hamstring muscle strength measured by a hand-held dynamometer. Secondary outcomes include pain, performance-based and self-reported physical function and sarcopenia status. The success of this study will provide scientific evidence of whether the relatively cheap and well-tolerated vitamin D supplement can improve quadriceps muscle strength, physical function, pain symptoms, and sarcopenia status of this increasingly large population for end-stage knee OA patients. The study has great clinical significance given Hong Kong's lengthy and growing waiting list for complete knee replacement procedures. Trial registration: The trial was registered on clinicaltrials.gov (NCT05981534) on 31st July 2023.

Sex differences in the radiographic and symptomatic prevalence of knee and hip osteoarthritis

Recognising sex differences in disease prevalence can lead to clues as to its pathogenesis, for example the role of hormonal factors and related influences such as body composition, as well as forming the basis for new treatments. However, if different methods are used to define the disorder it can be difficult to explore differences in prevalence, making it necessary to draw on multiple sources of evidence. This narrative review addresses sex differences in the prevalence of knee and hip osteoarthritis, which are the most common forms of large joint osteoarthritis. Females appear to have a higher prevalence of knee osteoarthritis across a wide range of disease definitions, while findings for the hip vary depending on how the disease is defined. Clinically or symptomatically defined hip osteoarthritis is more common in females, whereas radiographically defined hip osteoarthritis is more common in males. Therefore, understanding sex differences in large joint arthritis requires consideration that osteoarthritis, as defined structurally, more commonly affects females at the knee, whereas the opposite is true at the hip. Furthermore, despite structural changes in hip osteoarthritis being more common in males, symptomatic hip osteoarthritis is more common in females. The basis for these disparities is currently unclear, but may reflect a combination of hormonal, biomechanical and behavioural factors.

Targeting the TRPV1 pain pathway in osteoarthritis of the knee

INTRODUCTION

The growing prevalence and lack of effective pain therapies for knee osteoarthritis (KOA) results in a substantial unmet need for novel analgesic therapies. The transient receptor potential vanilloid 1 (TRPV1) receptor is expressed in subsets of nociceptive sensory neurons and has major roles in pain transmission and regulation. In the structures of the knee joint, nociceptors are present in abundance.

AREAS COVERED

TRPV1-expressing nociceptors in the knee represent a rational target to modulate activity at the origin of the pain pathway in KOA and may avoid systemic side effects seen with currently available analgesics. TRPV1 antagonists can induce analgesia, but hyperthermia and thermal hypesthesia side effects have limited their utility. Clinical development of TRPV1 agonists for pain management has progressed further than that of TRPV1 antagonists. Capsaicin and resiniferatoxin have provided proof-of-concept for the modulation of TRPV1 activity in KOA.

EXPERT OPINION

Intra-articular administration of TRPV1 agonists enables direct delivery to target nerve terminals in the knee, offering a potentially transformative approach for the management of pain associated with KOA. Here, we explore the advances in understanding innervation of the knee joint in KOA, the role of TRPV1-expressing neurons and progress in developing TRPV1 modulators for KOA.

Application of the IASP Grading System to Identify Underlying Pain Mechanisms in Patients With Knee Osteoarthritis: A Prospective Cohort Study

OBJECTIVES

This study aimed to apply the International Association for the Study of Pain (IASP) grading system for identifying nociplastic pain in knee osteoarthritis (KOA) awaiting total knee arthroplasty (TKA) and propose criteria to fine-tune decision-making. In addition, the study aimed to characterize a "probable" versus "no or possible" nociplastic pain mechanism using biopsychosocial variables and compare both groups in their 1-year post-TKA response.

METHODS

A secondary analysis of baseline data of a longitudinal prospective study involving 197 patients with KOA awaiting total TKA in Belgium and the Netherlands was performed. Two approaches, one considering 4 and the other 3 pain locations (step 2 of the grading system), were presented. Linear mixed model analyses were performed to compare the probable and no or possible nociplastic pain mechanism groups for several preoperative biopsychosocial-related variables and 1-year postoperative pain. Also, a sensitivity analysis, comparing 3 pain mechanism groups, was performed.

RESULTS

Thirty (15.22%-approach 4 pain locations) and 46 (23.35%-approach 3 pain locations) participants were categorized under probable nociplastic pain. Irrespective of the pain location approach or sensitivity analysis, the probable nociplastic pain group included more woman, was younger, exhibited worse results on various preoperative pain-related and psychological variables, and had more pain 1-year post-TKA compared with the other group.

DISCUSSION

This study proposed additional criteria to fine-tune the grading system for nociplastic pain (except for discrete/regional/multifocal/widespread pain) and characterized a subgroup of patients with KOA with probable nociplastic pain. Future research is warranted for further validation.

Evaluation and management of knee osteoarthritis

Knee osteoarthritis (KOA) significantly contributes to the global disability burden, with its incidence expected to escalate by 74.9% by 2050. The urgency to comprehend and tackle this condition is critical, necessitating an updated and thorough review of KOA. A systematic review up to February 26, 2024, has elucidated the principal aspects of KOA's pathogenesis, risk factors, clinical manifestations, and contemporary management paradigms. The origins of KOA are intricately linked to mechanical, inflammatory, and metabolic disturbances that impair joint function. Notable risk factors include age, obesity, and previous knee injuries. Diagnosis predominantly relies on clinical assessment, with radiographic evaluation reserved conditionally. The significance of rehabilitation assessments, informed by the International Classification of Functioning, Disability, and Health framework, is highlighted. Treatment strategies are diverse, prioritizing nonpharmacological measures such as patient education, exercise, and weight management, with pharmacological interventions considered adjuncts. Intra-articular injections and surgical options are contemplated for instances where conventional management is inadequate. KOA stands as a predominant disability cause globally, characterized by a complex etiology and profound effects on individuals' quality of life. Early, proactive management focusing on nonpharmacological interventions forms the cornerstone of treatment, aiming to alleviate symptoms and enhance joint function. This comprehensive review underscores the need for early diagnosis, individualized treatment plans, and the integration of rehabilitation assessments to optimize patient outcomes. Further research is needed to refine prevention strategies and improve management outcomes for KOA patients.

A Review of Current Approaches to Pain Management in Knee Osteoarthritis with a Focus on Italian Clinical Landscape

The global cases of knee osteoarthritis (KOA) are projected to increase by 74.9% by 2050. Currently, over half of patients remain dissatisfied with their pain relief. This review addresses unmet needs for moderate-to-severe KOA pain; it offers evidence and insights for improved management. Italian experts from the fields of rheumatology, physical medicine and rehabilitation, orthopedics, primary care, and pain therapy have identified several key issues. They emphasized the need for standardized care protocols to address inconsistencies in patient management across different specialties. Early diagnosis is crucial, as cartilage responds better to early protective and structural therapies. Faster access to physiatrist evaluation and reimbursement for physical, rehabilitative, and pharmacological treatments, including intra-articular (IA) therapy, could reduce access disparities. Concerns surround the adverse effects of oral pharmacological treatments, highlighting the need for safer alternatives. Patient satisfaction with corticosteroids and hyaluronic acid-based IA therapies reduces over time and there is no consensus on the optimal IA therapy protocol. Surgery should be reserved for severe symptoms and radiographic KOA evidence, as chronic pain post-surgery poses significant societal and economic burdens. The experts advocate for a multidisciplinary approach, promoting interaction and collaboration between specialists and general practitioners, to enhance KOA care and treatment consistency in Italy.

The use of a tibial stem in primary total knee arthroplasty for patients with a frontal deformity of more than ten degrees reduces the rate of postoperative pain

BACKGROUND

The use of a tibial stem for large deformities (> 10°) would reduce the incidence of pain. The aim of this study was to compare the effect of tibial stem on postoperative pain and aseptic loosening at the tibia in patients with a preoperative deformity > 10° in the frontal plane at 2 years follow-up.

METHODS

This was a retrospective single-center case-control study. Ninety-eight patients with deformities greater than 10° in the frontal plane and a BMI > 30 kg/m2 who had undergone posterior-stabilized (PS) total knee arthroplasty (TKA) with a tibial stem were matched using a propensity score to 98 patients who had undergone PS TKA without a tibial stem. The primary endpoint was the pain rate at 2 years. The secondary endpoints were the rate of aseptic loosening of the tibia at 2 years post-operatively.

RESULTS

A significant difference was found in the rate of postoperative pain at 2 years. It was higher in the group without tibial stem compared with the group with tibial stem (41.8% vs 17.3%, p = 0.0003). In the group without tibial stem, 24.4% of pain was mild, 61% moderate and no severe pain. In the tibial stem group, 47.1% of pain was mild, 41.2% moderate and no severe pain. A radiolucent line (RLL) was present at 2 years in 26.5% of prostheses in the without tibial stem group and in 9.2% of prostheses in the tibial stem group (p = 0.002). There was no difference between the two groups in terms of aseptic loosening.

CONCLUSION

The use of a tibial stem in primary TKA in patients with frontal deformities greater than 10° reduces postoperative pain and the presence of radiolucent lines.

Unravelling relationships between obesity, diabetes, and factors related to somatosensory functioning in knee osteoarthritis patients

OBJECTIVE

This study explores the association between obesity, diabetes, and somatosensory functioning in patients with knee osteoarthritis (OA), aiming to understand how metabolic conditions are related to pain mechanisms in this patient population. We hypothesized that higher body mass index (BMI), fat mass, and glycated hemoglobin levels (HbA1c) are associated with signs of altered somatosensory functioning.

METHODS

A cross-sectional analysis was conducted as part of a larger multicentre prospective cohort study. Data were collected from patients awaiting total knee arthroplasty in Belgium and the Netherlands. Associations between BMI, fat mass, HbA1c, and various pain-related variables were examined employing Pearson and Spearman correlation analyses which were further analyzed with linear regression techniques.

RESULTS

The study included 223 participants. Analysis revealed a significant although weak negative correlation between fat mass and pressure pain thresholds (PPT) at multiple locations, suggesting a link between higher fat mass and increased mechanical hyperalgesia. There were no significant correlations between BMI and pain-related outcomes. HbA1c levels showed very weak positive correlations with pain measures but did not withstand correction for multiple testing.

CONCLUSION

The findings indicate that fat mass may be closely associated with altered somatosensory functioning in patients with knee OA. However, no significant correlations were found between BMI or HbA1c levels and pain-related outcomes. Future research should focus on longitudinal studies to elucidate the causal relationships and further explore the impact of metabolic factors on pain mechanisms in this patient population. Key Points • The findings indicate that fat mass may be closely associated with altered somatosensory functioning in patients with knee OA.

A potential link between inflammatory profiles, clinical pain, pain catastrophizing and long-term outcomes after total knee arthroplasty surgery

BACKGROUND

Chronic postoperative pain after total knee replacement (TKR) is a major clinical problem. It is still unclear if specific inflammatory mediators are associated with long-term postoperative pain complications. The current exploratory study aimed to (1) evaluate a multiplex of inflammatory mediators 5 years after TKR surgery in patients with different degrees of postoperative pain intensities and (2) study any association of the markers with clinical pain intensity, cognitive and functional outcomes.

METHODS

Plasma samples were collected 5 years after TKR surgery from 76 knee patients (43 females; 33 males) and analysed for 44 inflammatory markers. Pain (using visual analogue scale, VAS), the pain catastrophizing scale (PCS) and the Oxford knee score (OKS) were evaluated. Patients were categorized as high or low groups based on VAS, PCS and OKS scores. Associations between inflammatory markers, VAS, PCS and OKS were analysed and the marker expressions were compared between groups.

RESULTS

Pearson's correlations found 12 biomarkers associated with VAS (p < 0.05), 4 biomarkers with PCS and 3 biomarkers with OKS (p < 0.05). Four markers were altered in patients suffering from high compared to low chronic postoperative pain, three markers were altered in high compared to low catastrophizers and three markers were altered in patients with poor functional scores (p < 0.05).

CONCLUSIONS

The present exploratory study suggests that low-grade inflammation might be present in a subset of patients with high pain, high catastrophizing and low function 5 years after TKR. These exploratory results provide insights into some of the long-term postoperative complications after TKR surgery.

SIGNIFICANCE STATEMENT

This exploratory study evaluated a subset of inflammatory markers and the association to clinical pain intensity, knee function and pain catastrophizing in patients 5 years after total knee replacement surgery. Our results provide insights into the understanding of the underlying mechanisms that may drive the long experience of pain after TKR surgery.

Predictors and Prevalence of Persistent Pain after Total Knee Arthroplasty in One-Year Follow-up

Background

Total knee arthroplasty (TKA) is one of the most common surgeries performed to reduce pain and disability in knee arthritis. Comprehension of the etiology and prevalence of persistent postoperative knee pain can help reduce this pain and identify the predictive factors leading to it. This study aimed to investigate the predictive factors and the prevalence of persistent pain after total knee arthroplasty in one-year follow-up.

Materials and Methods

This was a prospective cohort study. Demographic data including age, sex, body mass index (BMI), hospital anxiety and depression scale (HADS), and comorbidities were collected. In 242 patients, preoperative and postoperative Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were measured before and immediately after surgery and in 3-, 6-, and 12-month intervals during follow-up. Loosening of the prosthesis was also investigated by radiographic imaging in every postoperative visit.

Result

WOMAC pain decreased from a mean (standard deviation) of 49 before surgery to 18 at 6 months and 13 at 12 months. Despite this, the prevalence of moderate-to-severe persistent postoperative pain (PPP) was 13.22% (n = 32) and 9.09% (n = 22) at 6 and 12 months lower preoperative WOMAC (odd's ratio:2.8), loosening of the prosthesis (odd's ratio:1.9), higher HADS (odd's ratio:2.1) were main predictors for PPP in TKA patients as in rheumatoid arthritis (odd's ratio:1.2).

Conclusion

Loosening of the prosthesis and higher preoperative WOMAC scores are key factors in persistent post-TKA pain. Depression and anxiety are more popular among patients with more pain after TKA. RA is more prevalent in patients with PPP after TKA.

Description of pain associated with persistent postoperative pain after total knee arthroplasty

After total knee arthroplasty (TKA), approximately 20% of patients experience persistent postoperative pain (PPP). Although preoperative and postoperative pain intensity is a relevant factor, more detailed description of pain is needed to determine specific intervention strategies for clinical conditions. This study aimed to clarify the associations between preoperative and postoperative descriptions of pain and PPP. Fifty-two TKA patients were evaluated for pain intensity and description of pain preoperatively and 2 weeks postoperatively, and the intensities were compared. In addition, the relationship between pain intensity and PPP at 3 and 6 months after surgery was analyzed using a Bayesian approach. Descriptions of arthritis ("Throbbing" and "aching") improved from preoperative to 2 weeks postoperative. Several preoperative ("Shooting", "Aching", "Caused by touch", "Numbness") and postoperative ("Cramping pain") descriptors were associated with pain intensity at 3 months postoperatively, but only "cramping pain" at 2 weeks postoperatively was associated with the presence of PPP at 3 and 6 months postoperatively. In conclusion, it is important to carefully listen to the patient's complaints and determine the appropriate intervention strategy for the clinical condition during perioperative pain management.

Randomized Placebo-Controlled Trial of 60-Day Percutaneous Peripheral Nerve Stimulation Treatment Indicates Relief of Persistent Postoperative Pain, and Improved Function After Knee Replacement

OBJECTIVES

Total knee arthroplasty (TKA) is an effective surgery for end-stage knee osteoarthritis, but chronic postoperative pain and reduced function affect up to 20% of patients who undergo such surgery. There are limited treatment options, but percutaneous peripheral nerve stimulation (PNS) is a promising nonopioid treatment option for chronic, persistent postoperative pain. The objective of the present study was to evaluate the effect of a 60-day percutaneous PNS treatment in a multicenter, randomized, double-blind, placebo-controlled trial for treating persistent postoperative pain after TKA.

MATERIALS AND METHODS

Patients with postoperative pain after knee replacement were screened for this postmarket, institutional review board-approved, prospectively registered (NCT04341948) trial. Subjects were randomized to receive either active PNS or placebo (sham) stimulation. Subjects and a designated evaluator were blinded to group assignments. Subjects in both groups underwent ultrasound-guided placement of percutaneous fine-wire coiled leads targeting the femoral and sciatic nerves on the leg with postoperative pain. Leads were indwelling for eight weeks, and the primary efficacy outcome compared the proportion of subjects in each group reporting ≥50% reduction in average pain relative to baseline during weeks five to eight. Functional outcomes (6-minute walk test; 6MWT and Western Ontario and McMaster Universities Osteoarthritis Index) and quality of life (Patient Global Impression of Change) also were evaluated at end of treatment (EOT).

RESULTS

A greater proportion of subjects in the PNS groups (60%; 12/20) than in the placebo (sham) group (24%; 5/21) responded with ≥50% pain relief relative to baseline (p = 0.028) during the primary endpoint (weeks 5-8). Subjects in the PNS group also walked a significantly greater distance at EOT than did those in the placebo (sham) group (6MWT; +47% vs -9% change from baseline; p = 0.048, n = 18 vs n = 20 completed the test, respectively). Prospective follow-up to 12 months is ongoing.

CONCLUSIONS

This study provides evidence that percutaneous PNS decreases persistent pain, which leads to improved functional outcomes after TKA at EOT.

A Review of the Extent of Pain Catastrophizing in Patients Who Have Undergone Total Knee Replacement

OBJECTIVES

This study aimed to analyze the current status and influencing factors of pain catastrophizing in patients undergoing total knee replacement (TKR) and to provide a basis and reference for the clinical improvement of pain catastrophizing in these patients.

DESIGN

This study was designed in accordance with PRISMA guidelines.

DATA SOURCES

PubMed, the Web of Science, the Elton B. Stephens Company, the Cochrane Library, Embase, Chinese National Knowledge Infrastructure, the WanFang, Weipu and Chinese Biomedical Literature Databases.

REVIEW/ANALYSIS METHODS

A scoping review was performed using PubMed, the Web of Science, the Elton B. Stephens Company, the Cochrane Library, Embase, Chinese National Knowledge Infrastructure, the WanFang, Weipu, and Chinese Biomedical Literature Databases, and after literature screening and data extraction, the results were summarized.

RESULTS

A total of 23 articles were included in the study. Pain catastrophizing is mostly assessed using the Pain Catastrophizing Scale and the Coping Strategies Questionnaire. The level of pain catastrophizing is an independent predictor of pain in patients undergoing TKR and is influenced by demographic, psychological, co-morbid, and prognostic factors. Pain catastrophizing interventions mainly consist of surgery, physiotherapy, medication, and psychological therapy.

CONCLUSIONS

Pain catastrophizing involves multiple factors, and it is necessary to explore the predictors affecting pain catastrophizing, improve the systematic evaluation of pain catastrophizing and adopt the appropriate intervention methods.

The association of payer type on genicular radiofrequency neurotomy treatment outcomes: Results of a cross-sectional study

Background

Genicular radiofrequency neurotomy (GRFN) is an effective treatment for a subset of individuals with chronic knee pain. Previous studies demonstrate that Medicare and Medicaid beneficiaries report worse outcomes following various interventional procedures compared with commercially insured patients.

Objective

Evaluate the association of payer type on GRFN treatment outcomes.

Methods

Consecutive patients who underwent GRFN at a tertiary academic center were contacted for participation. Demographic, clinical, and procedural characteristics were collected from electronic medical records. Outcome data were collected by standardized telephone survey at 6-12 months, 12-24 months and ≥24 months. Treatment success was defined as ≥50% numerical pain rating scale (NPRS) score reduction from baseline. Data were analyzed using descriptive statistics for demographic, clinical, and procedural characteristics. Logistic and Poisson regression analyses were performed to examine the association of variables of interest and pain reduction.

Results

One hundred thirty-four patients treated with GRFN (mean 65.6 ± 12.7 years of age, 59.7% female) with a mean follow-up time of 23.3 ± 11.3 months were included. Payer type composition was 48.5% commercial (n = 65), 45.5% Medicare (n = 61), 3.7% Medicaid (n = 5), 1.5% government (n = 2), and 0.8% self-pay (n = 1). Overall, 47.8% of patients (n = 64) reported ≥50% NPRS score reduction after GRFN. After adjusting for age, follow-up duration, Kellgren-Lawrence osteoarthritis grade, baseline opioid use, antidepressant/antianxiety medication use, history of knee replacement, and number of RFN lesions placed, the logistic regression model showed no statically significant association between payer type and treatment outcome (OR = 2.11; 95% CI = 0.87, 5.11; p = 0.098).

Discussion/conclusion

In this study, after adjusting for demographic, clinical, and procedural characteristics, we found no association between payer type and treatment success following GRFN. This observation contrasts findings from other interventional studies reporting an association between payer category and treatment success.

Does pain intensity after total knee arthroplasty depend on somatosensory functioning in knee osteoarthritis patients? A prospective cohort study

The objective of this study is to determine whether the change in pain intensity over time differs between somatosensory functioning evolution profiles in knee osteoarthritis (KOA) patients undergoing total knee arthroplasty (TKA). This longitudinal prospective cohort study, conducted between March 2018 and July 2023, included KOA patients undergoing TKA in four hospitals in Belgium and the Netherlands. The evolution of the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale pain over time (baseline, 3 months, and 1 year post-TKA scores) was the outcome variable. The evolution scores of quantitative sensory testing (QST) and Central Sensitization Inventory (CSI) over time (baseline and 1 year post-TKA scores) were used to make subgroups. Participants were divided into separate normal, recovered, and persistent disturbed somatosensory subgroups based on the CSI, local and widespread pressure pain threshold [PPT] and heat allodynia, temporal summation [TS], and conditioned pain modulation [CPM]. Linear mixed model analyses were performed. Two hundred twenty-three participants were included. The persistent disturbed somatosensory functioning group had less pronounced pain improvement (based on CSI and local heat allodynia) and worse pain scores 1 year post-TKA (based on CSI, local PPT and heat allodynia, and TS) compared to the normal somatosensory functioning group. This persistent group also had worse pain scores 1 year post-TKA compared to the recovered group (based on CSI). The study suggests the presence of a "centrally driven central sensitization" subgroup in KOA patients awaiting TKA in four of seven grouping variables, comprising their less pain improvement or worse pain score after TKA. Future research should validate these findings further. The protocol is registered at clinicaltrials.gov (NCT05380648).

Preoperative frailty predicts postoperative pain after total knee arthroplasty in older patients: a prospective observational study

PURPOSE

Frailty is reportedly associated with postoperative adverse outcomes and may increase the risk of post-surgical pain. Our study aimed to explore whether frailty was an independent risk factor for pain after total knee arthroplasty (TKA) in older patients.

METHODS

Included in this prospective observational study were patients aged 65 or older who underwent primary TKA. Frailty of the patients was assessed before surgery using the comprehensive geriatric assessment-frailty index and pain was evaluated before and after surgery using the Numerical Rating Scale.

RESULTS

Of the 164 patients including 125 females with a mean age of 71.4 ± 4.6 years, 51 patients were identified as being frail. Patients with chronic post-surgical pain had a significantly higher frailty index than those without chronic post-surgical pain, which was the same in patients with acute post-surgical pain. After adjusting for other confounding factors, frailty was shown to be an independent risk factor for both acute (OR: 13.23, 95% CI 3.73-46.93, P < 0.001) and chronic post-surgical pain (OR: 4.24, 95% CI 1.29-14.00, P = 0.02). The area under the receiver operating characteristic curve for frailty predicting chronic post-surgical pain was 0.73 (P < 0.001, 95% CI 0.65-0.81).

CONCLUSIONS

Our findings demonstrated that preoperative frailty in older patients was a predictor of acute and chronic post-surgical pain after TKA, suggesting that frailty assessment should become a necessary procedure before operations, especially in older patients.

The effect of dextrose prolotherapy on patients diagnosed with knee osteoarthritis: A comprehensive systematic review and meta-analysis of interventional studies

Background and Aims

The primary objective of this systematic review and meta-analysis was to assess the impact of dextrose prolotherapy on individuals diagnosed with knee osteoarthritis (KOA).

Methods

To conduct a thorough investigation, a variety of leading international databases were checked, including PubMed (Medline), Scopus, Web of Sciences, EMBASE (Elsevier), ClinicalTrials.gov, and the Cochrane Library. The search covered a period from January 2000 to the end of June 2023, which facilitated the collection of relevant studies.

Results

The findings of the study revealed that when the studies utilizing the Western Ontario McMaster Universities Index tool (WOMAC) were combined, patients with KOA who received prolotherapy experienced an improvement in function compared with those who received other treatments (SMD: 0.20; 95% Confidence Interval [1]: -0.11, 0.51; p value SMD = 0.221; I 2: 78.49%; p heterogeneity < 0.001). Additionally, there was a decrease in mean pain and stiffness among patients who received prolotherapy compared with those who received other treatments or a placebo [(SMD: -0.95; 95% CI: -1.14, -0.76; p value SMD < 0.001; I 2: 59.35%; p heterogeneity = 0.070) and (SMD: -0.21; 95% CI: -0.32, -0.10; p value SMD < 0.001; I 2: 88.11%; p heterogeneity < 0.001)]. Furthermore, based on the Visual Analog Scale (VAS) score, there was a reduction of 0.81 units out of 10 in mean pain for patients with KOA who received prolotherapy (SMD: -0.81; 95% CI: -5.63, 4.10; p value SMD = 0.693; I 2: 48.54%; p heterogeneity = 0.08).

Conclusion

Drawing from the data analysis performed in this meta-analysis, it is apparent that dextrose prolotherapy exhibits promising effectiveness in reducing joint pain and stiffness, as well as improving functional performance in individuals suffering from KOA. Furthermore, it is recommended that forthcoming studies incorporate follow-up periods to guide decisions concerning the duration of prolotherapy's effects.

Genicular nerve radiofrequency ablation: a systematic review of application for perioperative pain control in total knee arthroplasty and as treatment for chronic pain in well-appearing total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is a successful treatment for end-stage osteoarthritis, yet some patients still experience postoperative pain. Genicular nerve radiofrequency ablation (GNRFA) has become a potential modality to address pain in TKA. This systematic review aims to critically analyze the applicability of GNRFA in perioperative pain control prior to TKA, as well as a treatment modality for chronic painful well-appearing TKA.

METHODS

PubMed, Medline, EMBASE, Google Scholar, Scopus, and COCHRANE databases, as well as the ClinicalTrials.gov register, were reviewed. The search included randomized controlled trials and cohort studies. The sample population focused on two cohorts; those who underwent TKA and utilized intentional GNRFA as a perioperative pain control modality, and those utilizing the treatment modality for chronic pain in well-appearing TKA. GNRFA was the intervention studied, and postoperative outcomes were compared with the control group, which consisted of those not receiving GNRFA.

RESULT

Eight total publications were identified as relevant to this search. Among the pre-TKA studies, there was variability in results; these inconsistencies were attributed to a lack of standardization, especially with regard to type, timing, and targeted nerves with ablation. Likewise, while the results were improved among the population with chronic painful TKA receiving GNRFA, these inconsistencies still existed.

CONCLUSIONS

Current evidence suggests GNRFA as a possible pre-TKA intervention to potentially minimize opioid consumption, patient-reported pain, length of stay, and increased range of motion and activity. However, the short-lived duration in the setting of chronically painful well-appearing TKA represents a major barrier that warrants further investigation. Limitations include small sample size, heterogeneity, lack of standardization of techniques among studies, and lack of direct comparison and meta-analysis. Further research should focus on the standardization of technique as well as analyzing various patient and health-system-related factors that correlate with sustained positive outcomes.

Mindfulness-Based Interventions for Perioperative Pain Management and Opioid Risk Reduction Following Surgery: A Stepped Care Approach

Surgical procedures often improve health and function but can sometimes also result in iatrogenic effects, including chronic pain and opioid misuse. Due to the known risks of opioids and the physical, emotional, and financial suffering that often accompanies chronic pain, there has been a call for greater use of complementary non-pharmacological treatments like mindfulness-based interventions. Mindfulness can be broadly described as an attentional state involving moment-by-moment meta-awareness of thoughts, emotions, and body sensations. An expanding number of randomized clinical trials have found strong evidence for the value of mindfulness techniques in alleviating clinical symptomology relevant to surgical contexts. The purpose of this review is to examine the empirical evidence for the perioperative use of mindfulness interventions. We present a mindfulness-based stepped care approach that first involves brief mindfulness to treat preoperative pain and anxiety and prevent development of postoperative chronic pain or opioid misuse. More extensive mindfulness-based interventions are then provided to patients who continue to experience high pain levels or prolonged opioid use after surgery. Finally, we review psychophysiological mechanisms of action that may be integral to the analgesic and opioid sparing effects of mindfulness.

Designing and developing a nature-based virtual reality with heart rate variability biofeedback for surgical anxiety and pain management: evidence from total knee arthroplasty patients

OBJECTIVES

Total knee arthroplasty (TKA) is one of the most common joint surgeries, with over a million procedures performed annually in the US. Over 70% of patients report moderate to high pain and anxiety surrounding TKA surgery, and 96% are discharged with an opioid prescription. This population requires special attention as approximately 90% of TKA patients are older adults and one of the riskiest groups prone to misusing opioids. This study aimed to develop and compare the efficacy of nature-based virtual reality (VR) with heart rate variability biofeedback (HRVBF) to mitigate surgical pain and anxiety.

METHODS

This randomized control trial recruited 30 patients (mean age = 66.3 ± 8.2 years, 23 F, 7 M) undergoing TKA surgery and randomly assigned to a control, 2D video with HRVBF, or VR with HRVBF group. A visual analog scale (VAS) was used to measure pain levels before and after the intervention. In addition, a second VAS and the State-Trait Anxiety Inventory (STAI) were used to measure anxiety before and after the intervention. Electrocardiogram (ECG) was used to continuously measure HRV and respiration rate in preoperative and postoperative settings.

RESULTS

VR and 2D-video with HRVBF decreased pain and anxiety post-intervention compared with the control group, p's <.01. On analyzing physiological signals, both treatment groups showed greater parasympathetic activity levels, and VR with HRVBF reduced pain more than the 2D video, p < .01.

CONCLUSIONS

Nature-based VR and 2D video with HRVBF can mitigate surgical pain and anxiety. However, VR may be more efficacious than 2D video in reducing pain.

Exercise and Pain Neuroscience Education for Patients With Chronic Pain After Total Knee Arthroplasty: A Randomized Clinical Trial

Importance

Up to 20% of patients develop chronic pain after total knee arthroplasty (TKA), yet there is a scarcity of effective interventions for this population.

Objective

To evaluate whether neuromuscular exercise and pain neuroscience education were superior to pain neuroscience education alone for patients with chronic pain after TKA.

Design, Setting, and Participants

A superiority randomized clinical trial was conducted at 3 outpatient clinics at Aalborg University Hospital in Denmark. Participants with moderate-to-severe average daily pain intensity and no signs of prosthesis failure at least 1 year after primary TKA were included. Participant recruitment was initiated on April 12, 2019, and completed on October 31, 2022. The 12-month follow-up was completed on March 21, 2023.

Interventions

The study included 24 sessions of supervised neuromuscular exercise (2 sessions per week for 12 weeks) and 2 total sessions of pain neuroscience education (6 weeks between each session) or the same pain neuroscience education sessions alone. The interventions were delivered in groups of 2 to 4 participants.

Main Outcomes and Measures

The primary outcome was change from baseline to 12 months using the mean score of the Knee Injury and Osteoarthritis Outcome Score, covering the 4 subscales pain, symptoms, activity of daily living, and knee-related quality of life (KOOS4; scores range from 0 to 100, with higher scores indicating better outcomes). The outcome assessors and statistician were blinded. All randomized participants were included in the intention-to-treat analysis.

Results

Among the 69 participants (median age, 67.2 years [IQR, 61.2-71.9 years]; 40 female [58%]) included in the study, 36 were randomly assigned to the neuromuscular exercise and pain neuroscience education group, and 33 to the pain neuroscience education-alone group. The intention-to-treat analysis showed no between-group difference in change from baseline to 12 months for the KOOS4 (7.46 [95% CI, 3.04-11.89] vs 8.65 [95% CI, 4.67-12.63] points; mean difference, -1.33 [95% CI, -7.59 to 4.92]; P = .68). Among the 46 participants who participated in the 12-month assessment in the 2 groups, 16 (34.8%) experienced a clinically important improvement (a difference of ≥10 points on the KOOS4) with no between-group difference. No serious adverse events were observed.

Conclusions and Relevance

In this randomized clinical trial, the results demonstrated that neuromuscular exercises and pain neuroscience education were not superior to pain neuroscience education alone in participants with chronic pain after TKA. Approximately one-third of the participants, regardless of intervention, experienced clinically important improvements. Future studies should investigate which patient characteristics indicate a favorable response to exercises and/or pain neuroscience education.

Trial Registration

ClinicalTrials.gov Identifier: NCT03886259.

Mechanisms and Preventative Strategies for Persistent Pain following Knee and Hip Joint Replacement Surgery: A Narrative Review

Chronic postsurgical pain (CPSP) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is a prevalent complication of joint replacement surgery which has the potential to decrease patient satisfaction, increase financial burden, and lead to long-term disability. The identification of risk factors for CPSP following TKA and THA is challenging but essential for targeted preventative therapy. Recent meta-analyses and individual studies highlight associations between elevated state anxiety, depression scores, preoperative pain, diabetes, sleep disturbances, and various other factors with an increased risk of CPSP, with differences observed in prevalence between TKA and THA. While the etiology of CPSP is not fully understood, several factors such as chronic inflammation and preoperative central sensitization have been identified. Other potential mechanisms include genetic factors (e.g., catechol-O-methyltransferase (COMT) and potassium inwardly rectifying channel subfamily J member 6 (KCNJ6) genes), lipid markers, and psychological risk factors (anxiety and depression). With regards to therapeutics and prevention, multimodal pharmacological analgesia, emphasizing nonopioid analgesics like acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), has gained prominence over epidural analgesia. Nerve blocks and local infiltrative anesthesia have shown mixed results in preventing CPSP. Ketamine, an N-methyl-D-aspartate (NMDA)-receptor antagonist, exhibits antihyperalgesic properties, but its efficacy in reducing CPSP is inconclusive. Lidocaine, an amide-type local anesthetic, shows tentative positive effects on CPSP. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) have mixed results, while gabapentinoids, like gabapentin and pregabalin, present hopeful data but require further research, especially in the context of TKA and THA, to justify their use for CPSP prevention.

Efficacy and safety of ozone therapy for knee osteoarthritis: an umbrella review of systematic reviews

The objective of this study is to evaluate the effectiveness and safety of ozone therapy (OT) in the treatment of knee osteoarthritis (KOA), which is the most common form of the disease. We analysed systematic reviews (SRs) of randomised controlled trials (RCTs) using the "A MeaSurement Tool to Assess systematic Reviews" (AMSTAR2) instrument to evaluate their quality. We developed a narrative synthesis report with eight SRs (15 RCTs/3,685 patients) to summarise the findings. The AMSTAR2 analysis indicated that all reviews had critically low confidence ratings. Statistically significant effects in pain reduction using OT compared to placebo groups were reported in three SRs. OT was shown to be comparable to other therapies in one SR and not superior in the other five. Six SRs highlighted the need for additional RCTs with improved methodological quality to confirm the efficacy of OT for KOA. SRs found fewer consistent effects for improving joint function. Regarding safety, seven SRs reported a low prevalence of minor adverse events linked with OT. Finally, this umbrella review highlights the beneficial effects and safety of OT in the treatment of KOA, particularly in pain control. The low methodological quality of RCTs and SRs limits the possibility of drawing conclusions on the effectiveness of the procedure in comparison to other therapies. Ensure adequate compliance with guidelines such as Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and AMSTAR2 has the ability to improve the quality of SRs in this area.

Time-Dependent Prediction Models for Individual Prognosis of Chronic Postsurgical Pain following Knee Replacement Based on an Extensive Multivariable Data Set

(1) Background: Clinically useful prediction models for chronic postsurgical pain (CPSP) in knee replacement (TKA) are lacking. (2) Methods: In our prospective, multicenter study, a wide-ranging set of 91 variables was collected from 933 TKA patients at eight time points up to one year after surgery. Based on this extensive data pool, simple and complex prediction models were calculated for the preoperative time point and for 6 months after surgery, using least absolute shrinkage and selection operator (LASSO) 1se and LASSO min, respectively. (3) Results: Using preoperative data only, LASSO 1se selected age, the Revised Life Orientation Test on pessimism, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-subscore pain and the Timed "Up and Go" Test for prediction, resulting in an area under the curve (AUC) of 0.617 and a Brier score of 0.201, expressing low predictive power only. Using data up to 6 months after surgery, LASSO 1se included preoperative Patient Health Questionnaire-4, Knee Injury and Osteoarthritis Outcome Score (KOOS)-subscore pain (pain) 3 months after surgery (month), WOMAC pain 3 and 6 months, KOOS subscore symptoms 6 months, KOOS subscore sport 6 months and KOOS subscore Quality of Life 6 months. This improved the predictive power to an intermediate one (AUC 0.755, Brier score 0.168). More complex models computed using LASSO min did little to further improve the strength of prediction. (4) Conclusions: Even using multiple variables and complex calculation methods, the possibility of individual prediction of CPSP after TKA remains limited.

Improvement in functional outcome 1 year after nonsurgical multidisciplinary treatment for chronic pain after total knee arthroplasty: A prospective cohort study

PURPOSE

The purpose of this study was to evaluate a multidisciplinary intervention developed for patients with debilitating chronic pain after total knee arthroplasty (TKA) unresponsive to existing treatment options.

METHODS

A treatment-based prospective cohort study was caried out in 30 TKA patients with debilitating chronic pain at least 1 year after TKA. The treatment was a multidisciplinary intervention. Main inclusion criteria: no indication for surgery. Primary outcome was function measured by KOOS-PS, OKS, OKS-APQ and WORQ. Secondary outcome measures were pain, fear of movement, self-efficacy, quality of life (QoL), health care and pain medication use, work rehabilitation and patient satisfaction. The assessments took place pre- and directly posttreatment, at 1, 3 and 12 months follow-up. The clinical relevance was assessed by predefined minimal important clinical change (MCIC).

RESULTS

At baseline patients were on average 64.7 (±7.9) years old, 67% were female, and they had knee pain for 42 (10-360) months. The results at 12-month follow-up: first, a significant improvement was shown in function, pain, fear of movement, self-efficacy and QoL. Second, in 38.5%-69.2% of patients clinical relevant improvement was shown for functional outcome, 31% for pain, and 50% for self-efficacy. Third, 42% of patients reported 'no healthcare use in the past three months'.

CONCLUSION

One year after a multidisciplinary treatment a clinically relevant improvement was shown in terms of function, pain, self-efficacy and QoL. It seems to be a promising treatment option in this difficult-to-treat patient group with debilitating chronic pain after TKA. Future research should examine the effect of the treatment in a larger study population, considering a control group, and focusing on the working population and evaluating cost-efficacy.

LEVEL OF EVIDENCE

Level II.

A prospective, randomized trial of liposomal bupivacaine compared to conventional bupivacaine on pain control and postoperative opioid use in adults receiving adductor canal blocks for total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is a commonly performed procedure to alleviate pain and improve functional limitations caused by end-stage joint damage. Effective management of postoperative pain following TKA is crucial to the prevention of complications and enhancement of recovery. Adductor canal blocks (ACB) with conventional bupivacaine (CB) provide adequate analgesia after TKA, but carry a risk of rebound pain following block resolution. Liposomal bupivacaine (LB) is an extended-release local anesthetic that can provide up to 72 h of pain relief. The objective of this study was to compare postoperative outcomes between ACBs using LB and CB after TKA.

METHODS

This single institution, prospective, randomized, clinical trial enrolled patients scheduled for TKA. Participants were randomized to receive ACB with either LB or CB. Pain scores up to 72 h postoperatively were assessed as the primary outcome. Opioid consumption and length of stay were evaluated as secondary outcomes.

RESULTS

A total of 80 patients were enrolled. Demographic and clinical characteristics were similar between the two groups. LB group showed significantly lower cumulative opioid use during the 72 h evaluated (P = 0.016). There were no differences in pain scores or length of stay between the groups.

CONCLUSION

The study demonstrated that LB ACBs led to significantly lower opioid consumption in the days following TKA without affecting pain scores or length of stay. This finding has important implications for improving postoperative outcomes and reducing opioid use in TKA patients. Previous studies have reported inconsistent results regarding the benefits of LB, highlighting the need for further research.

TRIAL REGISTRATION

This project was retrospectively registered with clinicaltrials.gov ( NCT05635916 ) on 2 December 2022.