CHRONIC EFFECTS OF A FLEXIBLE AND MINIMALIST FOOTWEAR ON CLINICAL, FUNCTIONAL AND GAIT BIOMECHANICAL ASPECTS IN THE KNEE OSTEOARTHRITIS: A SINGLE-BLIND RANDOMIZED CLINICAL TRIAL

Abstract

Purpose: Recent studies have shown that the acute use of shoes that mimic barefoot gait decrease substantially knee loads while walking in elderly with knee osteoarthritis (OA). Probably due to methodological difficulties to implement this type of conservative treatment during extended period, the effectiveness of minimalist footwear has not been evaluated yet in elderly patients with knee OA. The purpose is to describe a randomized clinical trial protocol for evaluating the therapeutic effect of a minimalist (flexible, non-heeled) and inexpensive footwear on clinical, functional, and biomechanical gait in elderly women with knee OA. Methods: Fifty six elderly women with knee OA grade 2 or 3 (Kellgren and Lawrence) will be randomized in blocks and allocated in the intervention group that will use a flexible non-heeled shoes- Moleca® forat least 6 hours daily or in the control group, which could not use these shoes or be under physical therapy or acupuncture treatment throughout these sis months. The use of Paracetamol 500 mg every six hour was allowed for both groups in case of pain. Moleca® (Calçados Beira Rio S.A., Novo Hamburgo, RS, Brazil) is a women's double canvas flexiblefl at walking shoe without heels, with a 5-mm anti-slip rubber sole and a 3-mm internal wedge of ethylene vinyl acetate. The mean weight is 172±19.6 g, ranging from 142 to 193 g depending on the size. Both groups will be followed during 6 months. They will be assessed at baseline condition, after 3 months (intervention group) and after 6 months of baseline condition(end of intervention, both groups). All the assessments will be performed by a physiotherapist that is blind to which group thepatient was allocated. The main outcome assessmentis the pain WOMAC score and the secondary outcomes are other WOMAC scores pain assessment (visual analogue scale - VAS), Lequesne index, Six-Minute Walk Test, and biomechanical gait analysis by means of 6 infrared cameras and a multi-component force plate to determine the knee adduction moment during gait. At baseline, all patients receive a diary to record the hours of daily use of footwear intervention. Every two weeks, the same physiotherapist carries phone calls to all patients in order to verify adherence to treatment and the correct filling this diary. Theinter group andinter-moments will be performed by repeated measures analysis of variance (α=0.05). This Trial was approved by the local Ethics Committee and was registered in ClinicalTrials.gov Identifier: NCT01342458. Results: Six hundred thirty-four elderly women have been contacted so far and 20 have already been allocated in the intervention group (9) and in the control (11). Five patients from intervention group have already completed all 3 assessments and finished the protocol. The preliminary results have shown that the elderly women of the intervention group have used the Moleca® shoe for an average monthly of 7 hours and 24 minutes (±3:47), corresponding to approximately 50% of the home-work hours of the day. Conclusion: This is the first randomized clinical trial protocol to assess the chronic effect of a minimalist footwear on the clinical, functional and gait biomechanics of elderly women with knee osteoarthritis. We expect that the use of Moleca® shoes for 6 months provides pain relief, reduction of the knee adduction moment while walking and improves joint function in elderly women with knee OA, and therefore can be considered as another inexpensive option for conservative OA treatment. The authors are pleased to acknowledge the financial support of State of São Paulo Research Foundation - FAPESP (processes: 2011/01640-8, 2011/03300-0, 2011/03069-6).