Mark Pyke

Preoperative widespread pain sensitization and chronic pain after hip and knee replacement: a cohort analysis

Abstract Chronic pain after joint replacement is common, affecting approximately 10% of patients after total hip replacement (THR) and 20% of patients after total knee replacement (TKR). Heightened generalized sensitivity to nociceptive input could be a risk factor for the development of this pain. The primary aim of this study was to investigate whether preoperative widespread pain sensitivity was associated with chronic pain after joint replacement. Data were analyzed from 254 patients receiving THR and 239 patients receiving TKR. Pain was assessed preoperatively and at 12 months after surgery using the Western Ontario and McMaster Universities Osteoarthritis Pain Scale. Preoperative widespread pain sensitivity was assessed through measurement of pressure pain thresholds (PPTs) at the forearm using an algometer. Statistical analysis was conducted using linear regression and linear mixed models, and adjustments were made for confounding variables. In both the THR and TKR cohort, lower PPTs (heightened widespread pain sensitivity) were significantly associated with higher preoperative pain severity. Lower PPTs were also significantly associated with higher pain severity at 12 months after surgery in the THR cohort. However, PPTs were not associated with the change in pain severity from preoperative to 12 months postoperative in either the TKR or THR cohort. These findings suggest that although preoperative widespread pressure pain sensitivity is associated with pain severity before and after joint replacement, it is not a predictor of the amount of pain relief that patients gain from joint replacement surgery, independent of preoperative pain severity.

The effect of local anaesthetic wound infiltration on chronic pain after lower limb joint replacement: A protocol for a double-blind randomised controlled trial

BackgroundFor the majority of patients with osteoarthritis (OA), joint replacement is a successful intervention for relieving chronic joint pain. However, between 10-30% of patients continue to experience chronic pain after joint replacement. Evidence suggests that a risk factor for chronic pain after joint replacement is the severity of acute post-operative pain. The aim of this randomised controlled trial (RCT) is to determine if intra-operative local anaesthethic wound infiltration additional to a standard anaethesia regimen can reduce the severity of joint pain at 12-months after total knee replacement (TKR) and total hip replacement (THR) for OA.Methods300 TKR patients and 300 THR patients are being recruited into this single-centre double-blind RCT. Participants are recruited before surgery and randomised to either the standard care group or the intervention group. Participants and outcome assessors are blind to treatment allocation throughout the study. The intervention consists of an intra-operative local anaesthetic wound infiltration, consisting of 60 mls of 0.25% bupivacaine with 1 in 200,000 adrenaline. Participants are assessed on the first 5 days post-operative, and then at 3-months, 6-months and 12-months. The primary outcome is the WOMAC Pain Scale, a validated measure of joint pain at 12-months. Secondary outcomes include pain severity during the in-patient stay, post-operative nausea and vomiting, satisfaction with pain relief, length of hospital stay, joint pain and disability, pain sensitivity, complications and cost-effectiveness. A nested qualitative study within the RCT will examine the acceptability and feasibility of the intervention for both patients and healthcare professionals.DiscussionLarge-scale RCTs assessing the effectiveness of a surgical intervention are uncommon, particulary in orthopaedics. The results from this trial will inform evidence-based recommendations for both short-term and long-term pain management after lower limb joint replacement. If a local anaesthetic wound infiltration is found to be an effective and cost-effective intervention, implementation into clinical practice could improve long-term pain outcomes for patients undergoing lower limb joint replacement.Trial registrationCurrent Controlled Trials ISRCTN96095682

Effect of local anaesthetic infiltration on chronic postsurgical pain after total hip and knee replacement: the APEX randomised controlled trials

Abstract Total hip replacement (THR) and total knee replacement (TKR) are usually effective at relieving pain; however, 7% to 23% of patients experience chronic postsurgical pain. These trials aimed to investigate the effect of local anaesthetic wound infiltration on pain severity at 12 months after primary THR or TKR for osteoarthritis. Between November 2009 and February 2012, 322 patients listed for THR and 316 listed for TKR were recruited into a single-centre double-blind randomised controlled trial. Participants were randomly assigned (1:1) to receive local anaesthetic infiltration and standard care or standard care alone. Participants and outcomes assessors were masked to group allocation. The primary outcome was pain severity on the WOMAC Pain Scale at 12 months after surgery. Analyses were conducted using intention-to-treat and per-protocol approaches. In the hip trial, patients in the intervention group had significantly less pain at 12 months postoperative than patients in the standard care group (differences in means: 4.74; 95% confidence interval [CI]: 0.95-8.54; P = 0.015), although the difference was not clinically significant. Post hoc analysis found that patients in the intervention group were more likely to have none to moderate pain than severe pain at 12 months than those in the standard care group (odds ratio: 10.19; 95% CI: 2.10-49.55; P = 0.004). In the knee trial, there was no strong evidence that the intervention influenced pain severity at 12 months postoperative (difference in means: 3.83; 95% CI: −0.83 to 8.49; P = 0.107). In conclusion, routine use of infiltration could be beneficial in improving long-term pain relief for some patients after THR.

Cardiopulmonary reserve as determined by cardiopulmonary exercise testing correlates with length of stay and predicts complications after radical cystectomy

To investigate whether poor preoperative cardiopulmonary reserve and comorbid state dictate high‐risk status and can predict complications in patients undergoing radical cystectomy (RC).

Rest Pain and Movement-Evoked Pain as Unique Constructs in Hip and Knee Replacements

There is limited information about the extent to which the association between preoperative and chronic postoperative pain is mediated via pain‐on‐movement or pain‐at‐rest. We explored these associations in patients undergoing total hip replacement (THR) and total knee replacement (TKR).