The efficacy of non-surgical treatment on pain and sensitization in patients with knee osteoarthritis: a pre-defined ancillary analysis from a randomized controlled trial

The objective of this study was to report the efficacy of a 3-month treatment program consisting of neuromuscular exercise, education, diet, insoles and pain medication (MEDIC-treatment) compared to usual care (two leaflets with information and treatment advice) in reducing pain-related measures and sensitization in patients with knee osteoarthritis (OA) not eligible for total knee replacement (TKR).  It included a  pre-defined ancillary analysis of the results at 3 months of a randomized controlled trial (RCT) of 100 patients randomized to MEDIC-treatment or usual care.  Outcomes were sensitization assessed at the knee, the lower leg and forearm using a handheld algometer, peak pain intensity in the previous 24 h, pain intensity after 30 min of walking, pain location and pattern, spreading of pain (a region-divided body chart) and the usage of pain medication.  The MEDIC group had larger improvements from baseline to 3 months in peak pain intensity (P = 0.02) and pain after 30 min of walking (P < 0.001) and in the number of body sites with pain (P = 0.04). There was no difference in the change in sensitization from baseline to 3 months between groups (P = 0.87), but sensitization decreased in both groups (P < 0.001).

The authors concluded that a non-surgical treatment program is more efficacious in reducing pain-related measures than usual care, while both are equally efficacious in reducing sensitization, indicating that mechanisms other than pain sensitization contribute to the perceived pain. The patients did not have severe symptomatic knee OA and hence pain sensitization may not yet have developed into a clinically relevant parameter or subgroups with less sensitization may exist.