Mogens Berg Laursen

Sensitization in patients with painful knee osteoarthritis

&NA; Pain is the dominant symptom in osteoarthritis (OA) and sensitization may contribute to the pain severity. This study investigated the role of sensitization in patients with painful knee OA by measuring (1) pressure pain thresholds (PPTs); (2) spreading sensitization; (3) temporal summation to repeated pressure pain stimulation; (4) pain responses after intramuscular hypertonic saline; and (5) pressure pain modulation by heterotopic descending noxious inhibitory control (DNIC). Forty‐eight patients with different degrees of knee OA and twenty‐four age‐ and sex‐matched control subjects participated. The patients were separated into strong/severe (VAS ≥ 6) and mild/moderate pain (VAS < 6) groups. PPTs were measured from the peripatellar region, tibialis anterior (TA) and extensor carpi radialis longus muscles before, during and after DNIC. Temporal summation to pressure was measured at the most painful site in the peripatellar region and over TA. Patients with severely painful OA pain have significantly lower PPT than controls. For all locations (knee, leg, and arm) significantly negative correlations between VAS and PPT were found (more pain, more sensitization). OA patients showed a significant facilitation of temporal summation from both the knee and TA and had significantly less DNIC as compared with controls. No correlations were found between standard radiological findings and clinical/experimental pain parameters. However, patients with lesions in the lateral tibiofemoral knee compartment had higher pain ratings compared with those with intercondylar and medial lesions. This study highlights the importance of central sensitization as an important manifestation in knee OA.

A Randomized, Controlled Trial of Total Knee Replacement

BACKGROUND More than 670,000 total knee replacements are performed annually in the United States; however, high-quality evidence to support the effectiveness of the procedure, as compared with nonsurgical interventions, is lacking. METHODS In this randomized, controlled trial, we enrolled 100 patients with moderate-to-severe knee osteoarthritis who were eligible for unilateral total knee replacement. Patients were randomly assigned to undergo total knee replacement followed by 12 weeks of nonsurgical treatment (total-knee-replacement group) or to receive only the 12 weeks of nonsurgical treatment (nonsurgical-treatment group), which was delivered by physiotherapists and dietitians and consisted of exercise, education, dietary advice, use of insoles, and pain medication. The primary outcome was the change from baseline to 12 months in the mean score on four Knee Injury and Osteoarthritis Outcome Score subscales, covering pain, symptoms, activities of daily living, and quality of life (KOOS4); scores range from 0 (worst) to 100 (best). RESULTS A total of 95 patients completed the 12-month follow-up assessment. In the nonsurgical-treatment group, 13 patients (26%) underwent total knee replacement before the 12-month follow-up; in the total-knee-replacement group, 1 patient (2%) received only nonsurgical treatment. In the intention-to-treat analysis, the total-knee-replacement group had greater improvement in the KOOS4 score than did the nonsurgical-treatment group (32.5 vs. 16.0; adjusted mean difference, 15.8 [95% confidence interval, 10.0 to 21.5]). The total-knee-replacement group had a higher number of serious adverse events than did the nonsurgical-treatment group (24 vs. 6, P=0.005). CONCLUSIONS In patients with knee osteoarthritis who were eligible for unilateral total knee replacement, treatment with total knee replacement followed by nonsurgical treatment resulted in greater pain relief and functional improvement after 12 months than did nonsurgical treatment alone. However, total knee replacement was associated with a higher number of serious adverse events than was nonsurgical treatment, and most patients who were assigned to receive nonsurgical treatment alone did not undergo total knee replacement before the 12-month follow-up. (Funded by the Obel Family Foundation and others; MEDIC ClinicalTrials.gov number, NCT01410409.).

Widespread sensitization in patients with chronic pain after revision total knee arthroplasty.

Summary Widespread sensitization is predominant in patients with pain after revision total knee arthroplasty. This is important when considering revision arthroplasty in the treatment of knee osteoarthritis. ABSTRACT Pain and sensitization are major issues in patients with osteoarthritis both before and after total knee arthroplasty (TKA) and revision TKA (re‐TKA). The aim of this study was to assess sensitization in patients with and without chronic pain after re‐TKAs. Twenty patients with chronic knee pain and 20 patients without pain after re‐TKA participated. Spreading of pain was evaluated as the number of pain sites using a region‐divided body chart. The pressure pain threshold (PPT) and pressure pain tolerance (PTT) were assessed by cuff algometry at the lower leg. Temporal summation of pain was assessed by recordings of the pain intensity on a visual analog scale (VAS) during repeated cuff pressure stimulations. Conditioning pain modulation (CPM) was recorded by experimental tonic arm pain by cuff pressure stimulation and assessment of PPTs on the knee, leg, and forearm using handheld pressure algometry. Participants with pain after re‐TKA compared to participants without pain demonstrated: (1) significantly more pain sites (P = .004), (2) decreased cuff PPTs and PTTs at the lower leg (P < .001), (3) facilitated temporal summation (P < .001), and (4) impaired CPM (P < .001). Additionally, significant correlations between knee pain intensity and cuff PPTs, temporal summation, and CPM and between total duration of knee pain and temporal summation were found (P < .05). This study demonstrated widespread sensitization in patients with pain after re‐TKA and highlighted the importance of ongoing nociceptive input for the chronification process. This has important implications for future revisions, and precautions should be taken if patients have widespread sensitization.

Presurgical assessment of temporal summation of pain predicts the development of chronic postoperative pain 12 months after total knee replacement

Abstract Patients with knee osteoarthritis demonstrate decreased pressure pain thresholds (PPTs), facilitated temporal summation (TS) of pain, and decreased conditioned pain modulation (CPM) compared with healthy controls. This study aimed to correlate preoperative PPTs, TS, and CPM with the development of chronic postoperative pain after total knee replacement (TKR) surgery. Knee pain intensity (visual analog scale [VAS]: 0-10), PPTs, TS, and CPM were collected before, 2 months, and 12 months after TKR. Patients were divided into a low-pain (VAS < 3) and a high-pain (VAS ≥ 3) group based on their VAS 12 months after TKR. The high-pain group (N = 17) had higher pain intensities compared with the low-pain group (N = 61) before surgery (P = 0.009) and 12 months after surgery (P < 0.001). The PPTs of the low-pain groups were normalized for all measurement sites comparing presurgery with 12 months postsurgery (P < 0.05, contralateral arm: P = 0.059), which was not the case for the high-pain group. The low-pain group showed a functional inhibitory CPM preoperatively and 12 months postoperatively (P < 0.05), which was not found in the high-pain group. The high-pain group had higher facilitated TS preoperatively and 12 months postoperatively compared with the low-pain group (P < 0.05). Preoperative TS level correlated to 12-month postoperative VAS (R = 0.240, P = 0.037). Patients who developed moderate-to-severe pain had pronociceptive changes compared with patients who developed mild pain postsurgery. Preoperative TS level correlated with the postoperative pain intensity and may be a preoperative mechanistic predictor for the development of chronic postoperative pain in patients with osteoarthritis after TKR.

Thromboprophylaxis only during hospitalisation in fast-track hip and knee arthroplasty, a prospective cohort study

Objectives International guidelines recommend thrombosis prophylaxis after total hip arthroplasty (THA) and total knee arthroplasty (TKA) for up to 35 days. However, previous studies often have hospital stays (length of stay; LOS) of 8–12 days and not considering early mobilisation, which may reduce incidence of venous thromboembolic events (VTE). We investigated the incidence of any symptomatic thromboembolic events (TEEs) with only in-hospital prophylaxis if LOS ≤5 days after fast-track THA and TKA. Design A prospective descriptive multicentre cohort study in fast-track THA and TKA from February 2010 to December 2011, with complete 90-day follow-up through the Danish National Patient Registry and patient files. Setting 6 Danish high-volume centres with a similar standardised fast-track setup, including spinal anaesthesia, opioid-sparing analgesia, early mobilisation, functional discharge criteria and discharge to own home. Participants 4924 consecutive unselected unilateral primary THA and TKAs in patients ≥18 years with no preoperative use of continuous ‘potent’ anticoagulative therapy (vitamin K antagonists). Exposure Prophylaxis with low-molecular-weight heparin or factor Xa-inhibitors only during hospitalisation when LOS ≤5 days. Outcomes Incidence of symptomatic TEE-related, VTE-related and VTE-related mortality ≤90 days postoperatively. Results LOS ≤5 days and thromboprophylaxis only during hospitalisation occurred in 4659 procedures (94.6% of total). Median LOS and prophylaxis duration was 2 days (IQR 2–3) with 0.84% (95% CI 0.62% to 1.15%) TEE and 0.41% (0.26% to 0.64%) VTE during 90-day follow-up. VTE consisted of five pulmonary embolisms (0.11% (0.05% to 0.25%)) and 14 deep venous thrombosis (0.30% (0.18% to 0.50%)). There were four (0.09% (0.04% to 0.23%)) surgery-related deaths, of which 1 (0.02% (0.00% to 0.12%)) was due to pulmonary embolism, and 6 (0.13% (0.06% to 0.28%)) deaths of unknown causes after discharge. Conclusions The low incidence of TEE and VTE suggests that in-hospital prophylaxis only, is safe in fast-track THA and TKA patients with LOS of ≤5 days. Guidelines on thromboprophylaxis may need reconsideration in fast-track elective surgery. Trial Registration ClinicalTrials.gov: NCT01557725

Facilitation of pain sensitization in knee osteoarthritis and persistent post-operative pain: A cross-sectional study

Around 20% of patients with osteoarthritis (OA) have chronic post‐operative pain after total knee arthroplasty (TKA) and often undergo revision surgery with unfavourable pain outcome. This study compared sensitization in pain patients with knee OA and after revision TKA (re‐TKA).

Comparison of trabecular metal cups and titanium fiber-mesh cups in primary hip arthroplasty: A randomized RSA and bone mineral densitometry study of 50 hips

Background Trabecular metal has shown promising results in experimental studies of bone ingrowth. Several clinical studies support these results. However, until now, no randomized clinical radiostereometric analysis (RSA) studies have been published. In this randomized RSA trial, we compared a new acetabular cup with a surface made of tantalum trabecular metal and a cup with a titanium fiber-mesh surface. Patients and methods Between 2004 and 2006, we operated 60 patients with noninflammatory hip arthritis. The patients were randomized to receive either an uncemented cup with a titanium fiber-mesh surface (Trilogy cup) or a cup with a trabecular tantalum surface (Monoblock cup). After 2 years, 50 patients had completed the study. The primary endpoint was cup migration within the first 2 years after surgery; the secondary endpoints were change in bone mineral density and Harris hip score at 3 months. Results Both cup types showed excellent fixation. RSA revealed minimal translation and rotation at 2 years. There was no statistically significant difference between the cup types with regard to translation. However, less rotation along the transverse axis was seen in the trabecular metal cups than in the fiber mesh cups: mean –0.01º (95% CI: –0.11 to 0.12) for trabecular metal cups and –0.60º (–0.72 to –0.48) for fiber-mesh cups (p = 0.04). The degree of periprosthetic bone loss was similar between the cup types in any of the regions of interest at 2 years of follow-up. 3 months postoperatively, we found a similar increase in Harris hip score in both groups: from around 50 to over 90. Interpretation We found promising early results concerning fixation of trabecular metal components to the acetabular host bone. However, we recommend a longer observation period to evaluate the outcome of this new cup design.

Faster recovery without the use of a tourniquet in total knee arthroplasty

Background and purpose— Tourniquet application is still a common practice in total knee arthroplasty (TKA) surgery despite being associated with several adverse effects. We evaluated the effects of tourniquet use on functional and clinical outcome and on knee range of motion (ROM). Patients and methods— 70 patients who underwent TKA were randomized into a tourniquet group (n = 35) and a non-tourniquet group (n = 35). All operations were performed by the same surgeon and follow-up was for 1 year. Primary outcomes were functional and clinical outcomes, as evaluated by KOOS and knee ROM. Secondary outcomes were intraoperative blood loss, surgical time and visibility, postoperative pain, analgesic consumption, and transfusion requirements. Results— Patients in the non-tourniquet group showed a better outcome in all KOOS subscores and better early knee ROM from surgery to week 8. No difference was detected at the 6- and 12-month follow-ups. Postoperative pain and analgesic consumption were less when a tourniquet was not used. Surgical time and visibility were similar between groups. Intraoperative blood loss was greater when not using a tourniquet, but no postoperative transfusions were required. Interpretation— This study shows that TKA without the use of a tourniquet results in faster recovery in terms of better functional outcome and improved knee ROM. Furthermore, reduced pain and analgesic use were registered and no intraoperative difficulties were encountered.

Analgesic and sedative effects of perioperative gabapentin in total knee arthroplasty: A randomized, double-blind, placebo-controlled, dose-finding study

Abstract Gabapentin has shown acute postoperative analgesic effects, but the optimal dose and procedure-specific benefits vs harm have not been clarified. In this randomized, double-blind, placebo-controlled dose-finding study, 300 opioid-naive patients scheduled for total knee arthroplasty were randomized (1:1:1) to either gabapentin 1300 mg/d (group A), gabapentin 900 mg/d (group B), or placebo (group C) daily from 2 hours preoperatively to postoperative day 6 in addition to a standardized multimodal analgesic regime. The primary outcome was pain upon ambulation 24 hours after surgery, and the secondary outcome was sedation 6 hours after surgery. Other outcomes were overall pain during well-defined mobilizations and at rest and sedation during the first 48 hours and from days 2-6, morphine use, anxiety, depression, sleep quality, and nausea, vomiting, dizziness, concentration difficulty, headache, visual disturbances, and adverse reactions. Pain upon ambulation (visual analog scale, mean [95% confidence interval]) 24 hours after surgery in group A vs B vs C was as follows: 41 [37-46] vs 41 [36-45] vs 42 [37-47], P = 0.93. Sedation (numeric rating scale, median [range]) 6 hours after surgery was as follows: 3.2 [0-10] vs 2.6 [0-9] vs 2.3 [0-9], the mean difference A vs C being 0.9 [0.2-1.7], P = 0.046. No between-group differences were observed in overall pain or morphine use the first 48 hours and from days 2-6. Sleep quality was better during the first 2 nights in group A and B vs C. Dizziness was more pronounced from days 2-6 in A vs C. More severe adverse reactions were observed in group A vs B and C. In conclusion, gabapentin may have a limited if any role in acute postoperative pain management of opioid-naive patients undergoing total knee arthroplasty and should not be recommended as a standard of care.

Clavicular nonunions treated with compression plate fixation and cancellous bone grafting: The functional outcome

We evaluated fracture healing and functional outcome after surgery in 16 patients with midshaft clavicular nonunion. The operative treatment consisted of compression plate fixation and autologous cancellous bone graft. The follow-up examination took place at an average of 54 months (range 26 to 90 months) after surgery. Radiographs were reviewed, and 12 patients underwent clinical review. All fractures united successfully. Two patients had a second operation because of loosening of the screws shortly after the first operation. Eleven of 12 patients had a good or excellent Constant score (>70 points). Nine of 12 patients returned to their preinjury activity level. Treatment with compression plate and autologous cancellous bone graft yields a high rate of healing and an acceptable functional outcome.