Dynamic wedging: Effective treatment for knee OA
By Carolyn Rogers
Individually calibrated shoes that provide dynamic wedging can significantly improve pain and function in patients with knee osteoarthritis (OA)—sometimes immediately, according to poster exhibit P278. The APOS system footwear can enable patients to walk painlessly during real-life activity, thus reacquiring neuromuscular skills and balance, the authors report.
Many treatments and devices have been developed to decrease the load on diseased articular surface in knee OA. However, these interventions usually require intensive physical therapy programs, resulting in low compliance.
The APOS system—developed by APOS Medical and Sports Technologies Ltd. of Hertzliya, Israel—is designed to unload the diseased articular surface during activity, strengthen dynamic stabilizers, and train neuromuscular control by means of controlled biomechanical perturbations.
The footwear involves the use of semispherical, individually calibrated implants that are placed on the soles of the shoes at the hindfoot and forefoot. These rubber implants can move medially, laterally, forward, and backward, and may be individually adjusted in order to balance loading.
To examine the effectiveness of the APOS system in reducing pain and improving function, the researchers conducted a double-blind study of 61 knee OA patients. The patients were randomized into active and placebo groups, and underwent eight weeks of treatment. Patients in the placebo group wore shoes that appeared identical to those worn by the treated group, but did not include the rubber implants on the soles.
Evaluation was performed at baseline, four weeks and eight weeks, using Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and the aggregated Locomotor Function (ALF) scale as primary outcome measures. The visual analog scale (VAS), the Short Form-36, and the Knee Society (KS) score were used as secondary outcome measures.
The findings: Improved function, 70% decrease in pain
Over time, significant differences were observed between the two groups for all outcome measures. Researchers noted a 70% decrease in pain in the treated group, and a 33% improvement in function. In the control group, a slight deterioration was observed by the end of the study.
The lead researcher for poster exhibit P278 was Professor Nahum Halperin, MD, of Rishon Le Zion, Israel. Additional researchers on the team included Yaron Bar-Ziv, MD, of Yokneam, Israel; Yiftah Beer, MD; Yuval Ran, MD, of Petach-Tiqwa, Israel; Shaike Benedict, MD, of Moshav Benaya, Israel; and Nahum Halperin, MD. The presenter, Ronen Debi, MD of Double Bay, Australia, has a financial relationship with APOS Medical & Sports Technologies Ltd. (Hertzliya, Israel) related to the topic of this manuscript.