Risk Of Persistent Postoperative Pain Research Articles

Revitalizing Postoperative Pain Management in Enhanced Recovery After Surgery via Inter-departmental Collaboration Toward Precision Medicine: A Narrative Review.

This narrative review explores the crucial aspects of postoperative pain management within the framework of Enhanced Recovery After Surgery (ERAS). It emphasizes the significance of effective and secure pain management, highlighting its impact on patient well-being, surgical outcomes, and hospital stays. The inadequacy of perioperative pain relief increases the risk of persistent postoperative pain, emphasizing the need to challenge the notion that pain is expected after surgery. The goals of postoperative pain management extend beyond mere relief, encompassing comfortable sleep, pain-free rest, and liberation from pain during initial recovery. Inadequate pain management can lead to complications such as heightened postoperative bleeding and an increased risk of thrombosis. The review delves into various analgesic methods, their complications, and safety measures.ERASprograms, focused on reducing complications and medical costs, emphasize the importance of judicious postoperative pain management and active rehabilitation. The review discusses complications associated with analgesic methods like opioids, epidural analgesia, and adjuvant analgesics. Collaboration within the perioperative management team is crucial for effective postoperative pain relief. Interdepartmental collaboration is essential for evaluating surgical procedures, analgesic methods, and crisis management strategies. The review concludes by integrating precision medicine into postoperative pain management, emphasizing the potential of genetic information in assessing pain sensitivity. It underscores the importance of inter-departmental collaboration and information gathering for the successful implementation of precision medicine tailored to each facility's perioperative management systems. Additionally, the impact of artificial intelligence (AI) on preoperative risk assessment and innovative monitoring techniques is discussed, paving the way for the advancement of precision medicine in postoperative pain management.

New Insights Into the Pharmacological Management of Postoperative Pain: A Narrative Review.

Postoperative pain is prevalent and often undertreated. There is a risk that untreated or suboptimally treated postoperative pain may transition into chronic postoperative pain, which can be challenging to treat. Clinical guidelines recommend the use of multimodal analgesia, including non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen, and, in some cases, opioids. NSAIDs are a broad class of drugs with different attributes such as cyclo-oxygenase (COX)-1 or COX-2 selectivity, onset of action, and analgesic potency. NSAIDs are associated with gastrointestinal and cardiovascular side effects and should be administered at the lowest effective dose for the shortest effective duration but can be effective in postoperative pain. The role of opioids in postoperative analgesia is long-standing but has recently come under scrutiny. Opioids are often used in multimodal analgesic combinations in such a way as to minimize the total consumption of opioids without sacrificing analgesic benefit. Special clinical considerations are required for surgical patients already on opioid regimens or with opioid use disorder. A particularly useful fixed-dose combination product for postoperative analgesia is dexketoprofen-tramadol, which confers safe and effective postoperative pain control and reduces the risk of persistent postoperative pain.

Persistent Pain After Cardiac Surgery: Prevention and Management.

Persistent postoperative pain (PPP) after cardiac surgery is a significant complication that negatively affects patient quality of life and increases health care system burden. However, there are no standards or guidelines to inform how to mitigate these effects. Therefore, in this review, we will discuss strategies to prevent and manage PPP after cardiac surgery. Adequate perioperative analgesia may prove instrumental in the prevention of PPP. Although opioids have historically been the primary analgesic approach to cardiac surgery, an opioid-sparing strategy may prove advantageous in reducing side effects, avoiding secondary hyperalgesia, and decreasing risk of PPP. Implementing a multimodal analgesic plan using alternative medications and regional anesthetic techniques may offer superior efficacy while reducing adverse effects.

Inguinal hernia repair among men: development and validation of a preoperative risk score for persistent postoperative pain.

Persistent postoperative pain (PPP) is a prevalent complication after inguinal hernia repair. The aim of this study was to develop and validate a preoperative risk score for PPP. We developed the risk score based on a cohort of 2,508 Danish men, who answered a questionnaire six months after inguinal hernia repair performed 2015-2016. PPP was defined as a numerical rating scale score ≥ 2 during activity six months postoperatively. Logistic regression analyses were undertaken to determine statistically significant predictors of PPP. Univariable analysis selected potential predictors with a p value ≤ 0.20, and a subsequent multivariable model was built using backward elimination with a criterion of p value < 0.10. We created a risk score based on the β coefficients of the multivariable model. The risk score was validated internally using Hosmer-Lemeshow goodness of fit test, calibration belt test, and receiver operating characteristic curve analyses with 95% confidence intervals based on the bootstrap analysis. External validation was performed in a cohort of 293 men recruited preoperatively. Predictors of PPP were age 18-49 and 50-59 (versus ≥ 60) years (p < 0.001), total load lifted > 1,000kg/day (p = 0.001), working in a bent-over position > 1h/day (p < 0.001), leisure-time physical activity < 2h/week (p = 0.009), increasing body mass index (per unit) (p < 0.003), and repair of recurrent hernia (p = 0.001).The preoperative risk score predicted risks of 6-61% in the development population. The model showed good internal and external validity. The results suggest that the risk of PPP after inguinal hernia repair can be predicted using a preoperative risk score.

Persistent postoperative pain after inguinal hernia repair in relation to occupational lifting and standing/walking: a 6-month follow-up study

ObjectivesThis study aims to evaluate the risk of persistent postoperative pain after inguinal hernia repair in relation to occupational lifting and standing/walking.MethodsWe conducted a 6-month follow-up study that included all...

Local anesthetics and regional anesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children: A Cochrane systematic review and meta-analysis update

BackgroundRegional anesthesia may mitigate the risk of persistent postoperative pain (PPP). This Cochrane review, published originally in 2012, was updated in 2017. MethodsWe updated our search of Cochrane CENTRAL, PubMed, EMBASE and CINAHL to December 2017. Only RCTs investigating local anesthetics (by any route) or regional anesthesia versus any combination of systemic (opioid or non-opioid) analgesia in adults or children, reporting any pain outcomes beyond three months were included.Data were extracted independently by at least two authors, who also appraised methodological quality with Cochrane ‘Risk of bias’ assessment and pooled data in surgical subgroups. We pooled studies across different follow-up intervals. As summary statistic, we reported the odds ratio (OR) with 95% confidence intervals and calculated the number needed to benefit (NNTB). We considered classical, Bayesian alternatives to our evidence synthesis. We explored heterogeneity and methodological bias. Results40 new and seven ongoing studies, identified in this update, brought the total included RCTs to 63. We were only able to synthesize data from 39 studies enrolling 3027 participants in a balanced design.Evidence synthesis favored regional anesthesia for thoracotomy (OR 0.52 [0.32 to 0.84], moderate-quality evidence), breast cancer surgery (OR 0.43 [0.28 to 0.68], low-quality evidence), and cesarean section (OR 0.46, [0.28 to 0.78], moderate-quality evidence). Evidence synthesis favored continuous infusion of local anesthetic after breast cancer surgery (OR 0.24 [0.08 to 0.69], moderate-quality evidence), but was inconclusive after iliac crest bone graft harvesting (OR 0.20, [0.04 to 1.09], low-quality evidence). ConclusionsRegional anesthesia reduces the risk of PPP. Small study size, performance, null, and attrition bias considerably weakened our conclusions. We cannot extrapolate to other interventions or to children.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children.

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017. To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery. We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews. We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery. At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE. In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 39 studies, enrolling a total of 3027 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution. We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Does oversizing an uncemented cup increase post-operative pain in primary total hip arthroplasty?

It has been suggested that one of the factors related to persistent post-operative pain following total hip arthroplasty (THA) is to over sizing of the acetabular component. In order to investigate this potential issue, we retrospectively analysed a series of consecutive uncemented THA. We assessed the incidence of persistent post-operative pain and the size difference between the implanted acetabular component and the native femoral head. A total of 265 consecutive THAs were retrospectively identified. Standardised pre-operative radiographs were analysed using validated techniques to determine the native femoral head diameter. Post-operative standardised radiographs were reviewed and the acetabular orientation determined. Patients were sent postal questionnaires regarding their outcome and level of pain. Questionnaires were returned by 169 patients (189 hips, 71% response rate). A total of 17 were excluded due to inadequate radiographs., leaving 172 THA in the study group. The mean native femoral head (NFH) size was 47mm. The most common implanted acetabular component size was 52mm. The mean difference in cup to NFH diameter (delta) was 5.7mm (range - 6.1 to 15.4mm; 95% CI 5.3-6.2mm). A delta of > 6mm was found to be significant for predicting persistent post-operative pain (RR = 1.81; 95% CI 1.1-3.1; P = 0.027). Our study confirms that a delta of > 6mm is associated with an increased risk of persistent post-operative pain following THA. We recommend pre-operative templating in all uncemented THA to ensure the planned acetabular component is no more than 6mm larger than the NFH diameter.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children.

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017. To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery. We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews. We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery. At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE. In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 41 studies, enrolling a total of 3143 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution. We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Persistent Postoperative Pain: Pathophysiology, Risk Factors, and Prevention.

Persistent postoperative pain (PPOP) is the second most common reason for a patient to seek care at a chronic pain center. Many of the patients seen with prolapse or incontinence are at risk for developing PPOP as a result of the surgeries done for these problems. The pathophysiology of this disabling pain disorder is well understood, and the risk factors are easy to identify. Once identified, perioperative interventions can be offered to attempt to prevent PPOP. Evaluation of articles obtained using a MEDLINE search involving chronic pain and PPOP, including prevalence, pathophysiology, and prevention was reviewed. The concept of central censitization and the key role it plays in chronic pain disorders were also reviewed. A history of chronic pain (anywhere) as well as findings of levator myalgia, allodynia, and hypertonic pelvic floor disorders is critical in identifying patients at risk for PPOP. Identification of patients at risk allows the clinician to educate the patient about the risk of PPOP and the various perioperative interventions that can be used to prevent its development. Further studies will be required to determine how effective these interventions are in patients undergoing surgery for incontinence and/or pelvic organ prolapse.

Important development: Extended Acute Pain Service for patients at high risk of chronic pain after surgery

In this issue of the Scandinavian Journal of Pain Elina Tiippana ndher colleagues at thepain research centre anddivisionof anaeshesiology at Helsinki University Hospital in Finland report on their xperience two years after they established a bridge between the cute Pain Service and the chronic pain clinic [1]. The aim of the ervice termed Acute Pain Service-Out-Patient Clinic (APS-OPC) is to educe the risk of persistent postoperative pain. Their paper raises t least three issues:

Recent Management Advances in Acute Postoperative Pain

Acute postoperative pain remains a major problem, with both undertreatment and overtreatment leading to serious consequences, including increased risk of persistent postoperative pain, impaired rehabilitation, increased length of stay and/or hospital readmission, and adverse events related to excessive analgesic use, such as oversedation. New analgesic medications and techniques have been introduced that target the preoperative, intraoperative, and postoperative periods to better manage acute postoperative pain, with improvements in analgesic efficacy and safety over more traditional pain management approaches. This review provides an overview of these new analgesic medications and techniques. Specific topics that are discussed include the use of preoperative nonsteroidal anti-inflammatory drugs, anxiolytics, and anticonvulsants; intraoperative approaches such as neuraxial analgesia, continuous local anesthetic wound infusion, transversus abdominis plane block, extended-release epidural morphine, intravenous acetaminophen, and intravenous ketamine; and postoperative use of intravenous ibuprofen, new opioids (eg, tapentadol) or opioid formulations (morphine-oxycodone), and patient-controlled analgesia. New, targeted, analgesic medications and techniques may provide a safer and more effective approach to the management of acute postoperative pain than traditional approaches such as postoperative oral analgesics.

Preoperative Pain is the Strongest Predictor of Postoperative Pain and Diminished Quality of Life after Ventral Hernia Repair

With evolution of hernia repair surgery, quality of life (QOL) became a major outcome measure in nearly 350,000 ventral hernia repairs (VHRs) performed annually in the United States. This study identified predictors of chronic pain after VHR. A prospective database of patient-reported QOL outcomes at a tertiary referral center was queried from 2007 to 2010; 512 patients met inclusion criteria. Factors including demographics, medical comorbidities, preoperative symptoms, and hernia characteristics were analyzed using advanced statistical modeling. Average age was 56.4 years, 57.6 per cent were males, mean body mass index was 33 kg/m(2), hernia defect size was 138 cm(2), and 35.5 per cent were repaired laparoscopically. Preoperatively, 69 per cent of patients had mild and 28 per cent severe pain during some activities. Pain levels were elevated in the first month postoperatively; by 6 months, patients reported significant improvement. The most significant and consistent predictor of postoperative pain was the presence of preoperative pain (odds ratio, 2.1; 95% confidence interval, 1.4 to 3.0; P = 0.0001). Older patients and men had less postoperative pain, but they also had less preoperative pain, so these factors were not independent predictors. Patients with minimal preoperative symptoms uniformly experienced resolution of pain by 6 months postoperatively. Among patients with severe preoperative pain, one-third reported long-term resolution of pain, and one-third had persistent severe pain. The former group had smaller hernias (91 vs 194 cm(2), respectively, P = 0.015). Cases of new-onset, long-term pain after VHR were rare (less than 2%). Most patients' symptoms resolve by 6 months after surgery, but those with severe preoperative pain are at risk for persistent postoperative pain.

SNP in TNFα T308G is predictive for persistent postoperative pain following inguinal hernia surgery

Abstract Aim of investigation Persistent postoperative pain of some extent is seen in about 20% of patients after surgical operations, while 80% heal without chronic pain. The type of chronic pain that arises is mainly neuropathic, and is suggested to be in part regulated by genetic factors. In order to study the possible involvement of some candidate genes suggested to be involved in the processing of pain (BDNF, CACNA2D2, ORPM1, GRIK 3, GCH1 and TNF-α ), we performed a genetic association study in a well characterized clinical material of patients that had undergone surgery for inguinal hernia (n = 189). Of those 94 had developed a persistent postoperative pain state when investigated 2–3 years following the operation. The control group (n = 95) had undergone the same surgical procedure, and were pain free at follow up. Methods Genomic DNA was extracted from blood samples and genotyped by the Handy Bio-strand method and the TaqMan assay. Results The patients with persistent postoperative pain that had homozygous SNP in the TNF-α gene displayed increased risk of persistent postoperative pain with an odds risk of 2.42, compared the pain free controls. None of the other of the investigated genes were associated with significant risk of development of chronic pain following surgery. Conclusion The expression of TNF-α shows a significant impact on the risk of developing chronic pain after surgery. Further experimental and clinical studies are needed in order to fine map the TNF-α effect and to address underlying mechanisms.

Chronic postoperative pain and sensory changes: Two sides of the same coin?

In Europe 19% of the adult population suffer from chronic pain. f these, 15% have chronic posttraumatic/postoperative pain [1]. hronic pain occurs in 10–50% of all patients after surgery [2] and ust be regarded as a major health problem. Recent research has evealed that sensory changes frequently accompany chronic postperativepainand that thesemaybekey symptoms that canhelpus o understandwhy some patients develop persistent postoperative ain and others do not [3]. The current issue of Scandinavian Journal of pain contains a clincal study by von Sperling et al. [4] that examines the prevalence, haracter, and sensory changes andpersistentpain followingbreast eduction surgery. One of themain indications for breast reduction urgery is back and neck pain. In the present study breast reduction ave total relief from back and neck pain in half and partial relief n one third of the patients. Preoperative breast pain in 11 patients as fully or partially relieved in all. However, 20% suffered new nd persistent pain in their breasts as a consequence of the surgery. his was only of median pain intensity 2/10 (range 0–10/10), but % of all patients had chronic postoperative pain of moderate to evere intensity, with significant impact on daily activities. More han half of the patients with new postoperative pain met the crieria for neuropathic pain. In concert with recent trials [3,5,6] the revalence of persistent postoperative sensory disturbanceswas as igh as 54%, with about half reporting hypoesthesia and one third eporting hyperesthesia. The presence of sensory disturbanceswas ssociated with increased risk for persistent postoperative pain. oung age, sensory abnormality, sensory hypersensitivity, compliations to surgery (infection or haematoma) were all associated ith higher risk of postoperative pain. Thepresent trial indicates that even thoughanumberofpatients ave had their pain changed from chronic back and neck pain to hronic postoperative pain, the patient satisfaction was high both mong those with and those without pain. The main reason for his was that most of the patients with persistent postoperative ain had mild pain. However, it is a concern that 7% of the patients uffer from pain strong enough to significantly affect activities of aily life two years after surgery.

Prospective Relation between Catastrophizing and Residual Pain following Knee Arthroplasty: Two‐Year Follow‐Up

Pain is the primary indication for both primary and revision total knee arthroplasty (TKA); however, most arthroplasty outcome measures do not take pain into account. To document the prospective pain experience following TKA, with subjective pain-specific questionnaires to determine if comorbidities, preoperative pain or preoperative pain catastrophizing scores are predictive of long-term pain outcomes. Fifty-five patients with a primary diagnosis of osteoarthritis of the knee, who were scheduled to undergo TKA, were asked to fill out the McGill Pain Questionnaire (MPQ) and the Pain Catastrophizing Scale (PCS) preoperatively and at three, 12 and 24 months follow-up. Comorbidities were extracted from the Queen Elizabeth II Health Sciences Centre health information system. The overall response rate (return of completed questionnaires) was 84%. There was a significant decrease in the MPQ scores (P<0.05) postoperatively. PCS scores did not change over time. Receiver operating characteristic curves revealed the number of comorbidities per patient predicted the presence of pain postoperatively, as documented by the numerical rating subscale of the MPQ at 24 months (P<0.05). Receiver operating characteristic curves for preoperative PCS and rumination subscale scores predicted the presence of pain, as measured by the Pain Rating Index subscale of the MPQ at 24 months (P<0.05). Preoperative PCS scores and comorbidities were significantly higher in the persistent pain group (P<0.05). The number of comorbidities predicted the presence of pain at 24 months follow-up and, for the first time, preoperative PCS scores were shown to predict chronic postoperative pain. This may enable the identification of knee arthroplasty patients at risk for persistent postoperative pain, thus allowing for efficient administration of preoperative interventions to improve arthroplasty outcomes.