Pain after total knee arthroplasty: a narrative review focusing on the stratification of patients at risk for persistent pain.

The patient with a painful arthritic knee awaiting total knee arthroplasty (TKA) requires a multidisciplinary approach. Optimal control of acute post-operative pain and the prevention of chronic persistent pain remains a challenge. The aim of this paper is to evaluate whether stratification of patients can help identify those who are at particular risk for severe acute or chronic pain. Intense acute post-operative pain, which is itself a risk factor for chronic pain, is more common in younger, obese female patients and those suffering from central pain sensitisation. Pre-operative pain, in the knee or elsewhere in the body, predisposes to central sensitisation. Pain due to osteoarthritis of the knee may also trigger neuropathic pain and may be associated with chronic medication like opioids, leading to a state of nociceptive sensitisation called 'opioid-induced hyperalgesia'. Finally, genetic and personality related risk factors may also put patients at a higher risk for the development of chronic pain. Those identified as at risk for chronic pain would benefit from specific peri-operative management including reduction in opioid intake pre-operatively, the peri-operative use of antihyperalgesic drugs such as ketamine and gabapentinoids, and a close post-operative follow-up in a dedicated chronic pain clinic.

Lavand'homme P ，Thienpont E 《-》

Chronic pre-operative opioid use and acute pain after fast-track total knee arthroplasty.

Pre-operative opioid use has been suggested to increase post-operative pain and opioid consumption after total knee arthroplasty (TKA), but previous studies are either retrospective or inhomogeneous with regard to surgical procedures or control of analgesic regimes, or with few opioid-treated patients, hindering firm conclusions. In a prospective observational study, we investigated the effect of > 4 weeks pre-operative opioid use [none vs. low dose (< 30 mg morphine equivalents (eq.)) vs. high dose (> 30 mg morphine eq.] in patients scheduled for primary, unilateral TKA. All patients had well-defined multimodal opioid-sparring perioperative analgesic therapy, and continued any pre-operative opioid medication. The primary outcome was differences between groups in pain at rest and during walk for the first 6 post-operative days. Among 123 patients included, 115 were available for final analysis (93% follow-up rate). Post-operative pain during walk was significantly increased in both opioid-treated groups vs. non-opioid-treated patients (P < 0.009). Secondary analysis of combining all pre-operatively opioid-treated patients vs. opioid-free patients, showed significantly increased pain at rest and walk and increased post-operative opioid requirement - excluding pre-operative dosage - during the first post-operative week in opioid-treated patients (P = 0.001 and P = 0.007, respectively). Pre-operative opioid use increases the risk for post-operative pain at rest and walk, and increased opioid consumption after TKA.

Aasvang EK ，Lunn TH ，Hansen TB ，Kristensen PW ，Solgaard S ，Kehlet H ... -  《-》

The Acute to Chronic Pain Transition: Can Chronic Pain Be Prevented?

Pozek JP ，Beausang D ，Baratta JL ，Viscusi ER ... -  《-》

Subacute pain after total knee arthroplasty.

Sauter A ，Breivik H 《-》

The association between pre-operative pain sensitisation and chronic pain after knee replacement: an exploratory study.

Chronic pain after total knee replacement (TKR) is a prevalent condition, affecting about 20% of patients. The aim of this study was to explore the relationship between pre-operative pain thresholds and chronic pain after TKR. Patients listed for a TKR because of osteoarthritis participated in a Quantitative Sensory Testing (QST) session prior to surgery. Pressure pain thresholds (PPTs) and hot pain thresholds were assessed at the osteoarthritic knee and the forearm. Patients were followed-up at 1-year after TKR, and the severity of pain in the replaced knee was assessed using the WOMAC Pain score. Pre-operative median QST thresholds were compared to thresholds from a normative database collected from 50 people with no knee pain. The relationship between pre-operative pain thresholds and pain severity post TKR were tested using correlations. Fifty-one patients participated in a pre-operative QST session and completed a 1-year WOMAC Pain score. Pre-operatively, patients demonstrated evidence of localised (knee) and widespread (forearm) pain sensitisation in response to pressure stimuli compared to healthy participants. Pre-operative PPTs at the forearm were found to be significantly correlated with 1-year WOMAC Pain scores (r = 0.37, P = 0.008). This study provides preliminary evidence that pre-operative widespread pain sensitisation, measured using pressure algometry, may be associated with chronic pain after TKR. Further research is needed to explore the predictive value of an assessment of pre-operative widespread pain sensitisation in identifying who is likely to develop chronic pain after TKR.

Wylde V ，Palmer S ，Learmonth ID ，Dieppe P ... -  《-》