A single intra-articular knee injection of methylprednisolone plus lidocaine given 2 weeks before a 12-week exercise programme, did not improve pain sensitivity compared with placebo plus lidocaine in patients with knee osteoarthritis, researchers reported here on April 1 at the 2016 Osteoarthritis Research Society International (OARSI) World Congress.
Lead author Marius Henriksen, PhD, The Parker Institute and Frederiksberg University Hospital, Frederiksberg, Denmark, and colleagues randomised 100 patients with knee osteoarthritis to treatment with either corticosteroid injection or placebo (n = 50 each). Osteoarthritis was assessed both clinically and radiographically.
Treatment in the corticosteroid group consisted of 1 intra-articular knee injection with 1 ml of 40 mg/ml methylprednisolone dissolved in 4 ml of 10 mg/ml lidocaine, while for placebo patients, the injection consisted of 1 ml isotonic saline mixed with 4 ml of 10 mg/ml lidocaine.
Subsequently, all patients took part in a 12-week supervised exercise programme that began 2 weeks after the intra-articular injection.
In all, 45 patients in the corticosteroid group and 44 in the placebo group completed the study.
While the primary outcomes had shown no difference between the treatment groups on the pain subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS) (JAMA Intern Med 2015; 175:923-30, doi:10.1001/jamainternmed.2015.0461), the current analysis evaluated pain sensitivity using cuff-pressure algometry on the calf, both at the end of the exercise programme (week 14) and again at week 26.
Results at week 14 showed that the change from baseline (mean ± SE) in pressure pain threshold was 0.0 ± 0.8 kPa in the corticosteroid-treated patients, which was not significantly different (P = .626) than the finding for placebo patients (0.6 ± 0.8 kPa). At week 26, the values were 0.2 ± 0.8 kPa in the corticosteroid group and -0.6 ± 0.8 kPa in the placebo group, which was again not significantly different (P = .480).
Temporal summation showed an improvement from baseline in both groups, but here too without revealing statistically significant differences between treatments. The change was -4149 ± 1196 mm × sec in the corticosteroid group compared to -3764 ± 1196 mm × sec with placebo (p = 0.821) measured at Week 14, and -4128 ± 1196 mm × sec for corticosteroid versus -4020 ± 1196 mm × sec for placebo (p = 0.949) at Week 26.
The modified intention-to-treat (mITT) population for the pressure-pain threshold analysis included 50 patients in the corticosteroid group plus 49 patients in the placebo group, while for the temporal summation analysis, the mITT included 48 patients from each treatment group.[Presentation title: Intra-Articular Corticosteroids In Addition To Exercise For Reducing Pain Sensitivity In Knee Osteoarthritis: Exploratory Outcome From A Randomized Controlled Trial. Abstract 738]