Pain and recovery after total knee arthroplasty: a 12-month follow-up after a prospective randomized study evaluating Nefopam and Ketamine for early rehabilitation.

OBJECTIVES: Ketamine and nefopam has been documented to decrease pain intensity and improve rehabilitation after total knee arthroplasty (TKA). We conducted a follow-up study of a previously randomized clinical trial to determine the prevalence and risk factors of chronic pain 1 year after TKA and to assess the role of perioperative administration of ketamine and nefopam. MATERIALS AND METHODS: The original randomized, double-blind trial evaluated postoperative pain in 75 patients scheduled for TKA who received either a 48-hour infusion of ketamine or nefopam compared with placebo. The current study has evaluated patients at 6 and 12 months for the presence of chronic pain defined as a visual analogue scale ≥40 mm during a stair-climbing test. Other outcomes were incidence of neuropathic pain evaluated (DN4 score), active flexion of the knee, and functional outcome (KOOS-PS score). RESULTS: A total of 69 patients completed the trial. The prevalence of chronic pain at 12 months was 17.4% (95% confidence interval [CI], 10.2%-27.9%) without difference between the ketamine (12.5%), nefopam (13.7%), and placebo groups (26.1%). Prevalence of neuropathic pain was 10.2% (95% CI, 3%-17.3%). Ketamine reduced DN4 scores (P=0.02), increased knee flexion (P=0.0007), and KOOS-PS scores (P<0.0001) compared with placebo. A visual analogue scale score ≥60 mm in the postoperative period was the only risk factor associated with the occurrence of chronic pain (odds ratio 4.54; 95% CI, 1.17-17.67). DISCUSSION: After TKA, the intensity of postoperative pain is a risk factor of chronic pain on movement. Intraoperative ketamine seems to improve long-term results of rehabilitation in this setting.

Perineural ultrasound-guided catheter bacterial colonization: a prospective evaluation in 747 cases.

BACKGROUND AND OBJECTIVES: Ultrasound guidance is increasingly used for catheter insertion and could make it more complicated to guarantee aseptic insertion of catheters. The current study evaluated the incidence of colonization of ultrasound-guided perineural catheter (US-PNC) placed for postoperative analgesia. METHODS: We evaluated prospectively for 14 months 760 ultrasound-guided catheters in a single center placed under sterile conditions. Quantitative culture of all the catheters was performed after withdrawal. Colonization was defined as ≥10(3) colony-forming units/mL. Infection was defined as the isolation of the same microorganism from the colonized catheter and from blood culture and/or culture of an abscess. Univariate and multivariate logistic regression analyses were performed to determine the independent risk factors of US-PNC colonization. RESULTS: Incidences of colonization and infections were 10.4% (95% confidence interval [95% CI], 8.2%-14.4%) and 0.13% (95% CI, 0%-3.8%), respectively, in a total of 747 catheters. Coagulase-negative staphylococci colonization was documented in 69% of the colonized catheters. Local inflammation was more frequently noted when catheters were colonized (26.9% [95% CI, 15.2%-38.7%] versus 8.1% [95% CI, 4.2%-11.9%], P = 0.005). Independent factors for ultrasound-guided catheter colonization were duration of catheter placement more than 48 hours (odds ratio [OR], 4.9; 95% CI, 1.1-12.7; P = 0.003), diabetes (OR, 2.3; 95% CI, 1.4-9.6; P = 0.004), and antibiotic administration during the month preceding surgery (OR, 1.8; 95% CI, 1.5-7.8; P = 0.01). CONCLUSIONS: Although infection rate is low, there is a risk of ultrasound-guided catheter colonization that deserves careful monitoring of the insertion site in the postoperative period.

Postoperative efficacies of femoral nerve catheters sited using ultrasound combined with neurostimulation compared with neurostimulation alone for total knee arthroplasty.

BACKGROUND AND OBJECTIVE: Neurostimulation is commonly used to perform femoral nerve block. Ultrasound can be used to identify nerve structures and guide needle placement. The aim of this study was to compare postoperative analgesic efficiency when femoral nerve catheters were sited using ultrasound (in-plane approach) combined with neurostimulation or neurostimulation alone, for total knee arthroplasty. METHOD: Ninety-three patients were enrolled in this prospective, randomized, blind study to receive a continuous femoral nerve block performed using conventional neurostimulation or ultrasound guidance combined with neurostimulation. The primary endpoint was the postoperative 48 h total local anaesthetic consumption. Other outcomes included visual analogue scale scores at rest, after 12, 24 and 48 h; total oral opioid dose; onset time of femoral block; procedural time; knee flexion and complications. Results are expressed with medians (25-75th percentiles), mean ± SD and n (%), as appropriate. RESULTS: The onset time of sensory and motor block was faster in the ultrasound group [11 (6-17) min] than in the conventional group [16 (11-23) min, P = 0.009]. Total local anaesthetic dose was reduced [299 ± 45 vs. 333 ± 48 ml, (difference = 34.0 ml, 95% confidence interval 15.6-52.5 ml), P = 0.0003] and the time to the first analgesic request was lengthened [11 (7-13) vs. 7 (4-12) h, P = 0.034] in the ultrasound group. Visual analogue scale scores at 12, 24 and 48 h were lower in the ultrasound group as well as visual analogue scale scores during knee flexion at 48 h [14.5 (11.0-23.0) vs. 28.5 (21.0-43.5) mm, P < 0.0001]. Total oral morphine doses were 20 (0-40) vs. 40 (20-60) mg (P = 0.0065). Durations of hospital stay were comparable in both groups. CONCLUSION: Continuous perineural femoral catheter placement using ultrasound combined with neurostimulation and an in-plane approach reduces total doses of local anaesthetic, morphine consumption and improves postoperative pain management by comparison with neurostimulation alone.

Postoperative analgesia and early rehabilitation after total knee replacement: a comparison of continuous low-dose intravenous ketamine versus nefopam.

The effects of nefopam and ketamine on pain control and rehabilitation after total knee replacement were compared in a prospective, double blinded study. Seventy-five patients were randomly assigned to receive a 0.2mg kg(-1) bolus of nefopam or ketamine, followed by a 120microg kg(-1) h(-1) continuous infusion until the end of surgery, and 60microg kg(-1) h(-1) until the second postoperative day, or an equal volume of saline considered as placebo. Pain scores measured on a visual analog scale at rest and on mobilization, and patient-controlled intravenous morphine consumption, were assessed during 48h. We measured the maximal knee flexion on the third postoperative day, and the delay to obtain a 90 degrees flexion. Ketamine and nefopam reduced morphine consumption (p<0.0001). Pain scores, were lower at rest and on mobilization in the ketamine group compared to the two other groups at all times of measurement. Pain score were lower in patients receiving nefopam compared to placebo, on arrival in the recovery room and at 2h. Ketamine improved knee flexion on post operative day 3 (59 degrees [33-63] vs. 50 degrees [47-55] and 50 degrees [44-55] in ketamine, placebo and nefopam groups, respectively, p<0.0002) and decreased the delay to flex the knee at 90 degrees (9.1+/-4.2 vs. 12.3+/-4.0 days, in ketamine and placebo groups, respectively, p=0.01). Ketamine produces opioid-sparing, decreases pain intensity, and improves mobilization after total knee replacement. Nefopam achieves less significant results in that circumstances.