An Arthritis Research UK-funded study has cast doubt on the effectiveness of using lateral wedge insoles as a means of relieving pain levels among sufferers of medial knee osteoarthritis.
Medial knee osteoarthritis is the most common type of arthritis affecting the knee joint, affecting the inside of the knee between the femur and the tibia.
The University of Manchester team led by Dr Matthew Parkes assessed the efficacy of lateral wedge treatments – shoes and insoles designed to reduce pressure on the knee – in reducing pain, evaluating data from 12 trials involving almost 900 patients.
According to results published in the Journal of the American Medical Association, while the data showed some connection between the use of these wedges and a reduction in pain levels, the findings were extremely inconsistent and failed to provide any evidence of a clear link.
Moreover, the studies that compared lateral wedge treatments to neutral insoles showed there were no advantages at all associated with the lateral wedge options.
This type of insole fits underneath the sole of the shoe and are thicker on the outside than the inside, thereby tilting the foot inward and transferring the weight of the body to a different part of the foot.
However, the Arthritis Research UK-backed report would appear to suggest that the specific design of the insole itself did not have an impact, with the only studies showing any benefit being the ones in which their performance was compared against patients who were not using insoles at all.
The researchers said: ‘These results suggest that compared with control interventions, lateral wedges are not efficacious for the treatment of knee pain in persons with medial knee osteoarthritis.’
Arthritis Research UK is now funding a new clinical trial that will see the Manchester team investigating whether targeting specific sub-groups of people with medial osteoarthritis who respond biologically to wearing lateral wedge insoles gain benefit. A number of insoles and orthotics which have been designed to potentially lower the loads in the knee joint will be tested.
‘The current way that insoles are prescribed don’t appear to work, but this new trial gives us an opportunity to modify them for particular patients whom we think will respond,’ added the spokesman. Arthritis Research UK