Biomechanical Correction by Lateral Wedge Outsole in Osteoarthritis Knee Joint

Abstract

Background: Osteoarthritis (OA) Knee is one of the leading causes of pain and functional disability among painful joint conditions in adults. The overall prevalence of OA in India has been estimated to be around 28.7% which has been calculated based on data from five Indian states. Worldwide, the prevalence of OA is estimated to be around 9.6% in men and 18% in women aged over 60 years. Nearly, 45% of women over the age of 65-years have symptoms while radiological evidence is found in 70% of them. OA of knee joint is diagnosed using American College of Rheumatology Criteria (ACR).
Lateral wedges reduce the peak knee adduction moment and are advocated for knee osteoarthritis. However, some patients demonstrate adverse biomechanical effects with treatment. Clinical management is hampered by lack of knowledge about their mechanism of effect. We evaluated effects of lateral wedges on frontal plane biomechanics, to elucidate mechanisms of effect.
Materials and Methods: This prospective observational study was conducted on 80 patients between 40-65 years of age, 56 were females and 24 males. With grade II & grade III osteoarthritis according to Kallgren-Lawrence grading scale, who reported to OPD of PMR Department of MGMCH, Jaipur from April 2022 to September 2024.
- Diagnosis of knee osteoarthritis was established clinically based on ACR criteria.
- Pain was recorded on Visual Analogue Scale (VAS) and quality of life by SF-36.
- History, clinical examination and X-rays were taken in all patients.
- Biomechanical correction was given by using ¼ inches lateral wedge outsole in the footwear.
- Follow up was conducted on monthly bases from 1 ½ months and on 6 months for evaluation of results. Patients improved
symptomatically with pain and in quality of life.
Results: The mean age of the patients included was 52-years. All our patients presented with chronic pain in the knees and stiffness. The mean duration of symptoms at the time of presentation was 8-years. All of our patients had bilateral involvement of the knees showing medial joint space narrowing in radiographs. 56/80 patients were females, mostly housewives, and 24/80 were males with a history of prolonged standing at workplace. The mean weight of the patients was 60 ± 10 kg. The majority of our patients (50/80) were overweight having a BMI between 25 and 30 kg/m², (18/80) were obese, and (12/80) had a BMI < 25kg/m².
Conclusion: Use of lateral wedge outsoles signifies the redistribution of pressure and change in the ground reaction forces after shoe modification. Hence, lateral wedging provides symptomatic benefits in the mild and moderate OA knee.