Original Articles

By Dr. J S Prakash , Dr. Ashish Passi , Dr. J Prakash , Dr. Shiraz Bhatty , Dr. Anit Deane
Corresponding Author Dr. J S Prakash
CMC & Hospital, CMC & Hospital ,Ludhiana - India 141008
Submitting Author Dr. Jeewan S Prakash
Other Authors Dr. Ashish Passi
Deptt. Orthopedics , CMC , CMC - India 141008

Dr. J Prakash
Deptt. Gen. Surgery , CMC , Deptt. Gen. Surgery , CMC - India 141008

Dr. Shiraz Bhatty
Deptt.Orthopedics,GGS Medical College , BFUHS, Deptt. Orthopedics , GGS Medical College , Faridkot , Pb. - India 151203

Dr. Anit Deane
Deptt. Orthopedics, HIMS, Himalayan Instt. of Medical Sciences , HIHT , Dehradun,U'k - India 248140


Microcellular rubber , insoles , knee osteoarthritis , WOMAC score

Prakash JS, Passi A, Prakash J, Bhatty S, Deane A. Microcellular Rubber Insole in Management of Knee Osteoarthritis. WebmedCentral ORTHOPAEDICS 2014;5(1):WMC004505
doi: 10.9754/journal.wmc.2014.004505

This is an open-access article distributed under the terms of the Creative Commons Attribution License(CC-BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Submitted on: 06 Jan 2014 02:10:14 PM GMT
Published on: 07 Jan 2014 05:23:48 AM GMT


Orthotic devices inside footwear have been used for long for various indications . Literature is available comparing shoe insoles made of various materials. We present our observations from a prospective study wherein for the first time microcellular rubber insoles were prescribed and used by 44 patients afflicted with osteoarthritis in 84 knees . Outcome analyses  were based on  WOMAC’s index. The preliminary  study on management of knee OA using microcellular rubber insoles bore effective and  encouraging results.

Key words: Microcellular rubber, insoles, knee osteoarthritis, WOMAC score


Although the history of studies of  osteoarthritis [OA] spans  over a century, the condition itself is age old. Mid 1990’s witnessed the development of a new concept of OA as a group  of different disorders [osteoarthritic diseases] that share common risk factors, pathogenesis and pathology [04]. Osteoarthritis, also sometimes called osteoarthrosis by purists, or degenerative joint disease, is not a single disease but rather the clinical and pathological outcome of a range of disorders and conditions that lead to pain, disability and structural failure in synovial joints. OA  is commonest degenerative joint disease and affects knees , hips , hands and spine. It is characterised by degradation of joints, including cartilage surfaces and subchondral bone, causing joint space narrowing, pain, stiffness, swelling, tenderness and reduced physical function [11]. Knee is the commonest lower limb site for OA, with the disease affecting the tibiofemoral and patellofemoral joints either in isolation or in  combination. Medial tibiofemoral compartment is the most commonly affected  [medial 67%  versus lateral 16%] [08]

Osteoarthritis may be primary [idiopathic], rarely occurring before 35, polyarticular degenerative arthritis of unknown origin; or secondary when it is usually monoarticular,  predisposed by some other disorder/disease or earlier trauma .OA is a common, chronic disease affecting over one third of adults with the disease prevalence increasing with advancing age. The prevalence of both radiographically defined OA, and  of OA related disability, is  greater in obese women than in men. It is associated with pain and physical  disability  and imposes a significant personal, societal and economic burden [03 ,05]

Contemporary management modalities for knee OA include non pharmacologic, pharmacologic and surgical interventions depending upon severity of disease. A meta-analysis referred by Baker et al, 2007, [01] reports that 60% of OA trials assess drug therapies, and 26% assess surgical procedures.

Management strategies may be regarded as primary prevention [reduction of risk factors to reduce disease incidence], secondary prevention [interventions to slow/prevent progression to serious disease], or tertiary prevention [treatment of pain and disability] [03]

Three main types of non pharmacologic, non surgical biomechanical orthotic interventions are available and recommended by health professionals: shoe insoles, knee braces, and  foot orthoses [13]

Material & Methods

The present study was conducted between November 2011 and November 2013 including a minimum follow up of six months. Initially 75 patients diagnosed with knee OA enrolled for the study as per inclusion and exclusion criteria. 44 patients with 84 diseased knees were followed up till end of study. After taking informed consent history was recorded according to protocol  , patient was examined and initial WOMAC  score calculated .Radiographs were taken and OA graded according to Kellgren & Lawrence classification [06]. After the patient was seen by a consultant s/he was explained about the shoe insole/s required and available. Insoles used in this study were made of microcellular  rubber , 10 mm thick full length inserts trimmed according to shape of patient’s footwear. S/he was asked to wear the same with footwear and note the duration. S/he was followed up every 2, 4, 6 months and WOMAC score [02] recorded along with relevant findings

Observation , Result and Analysis

44 patients [ 30 females (68%) and 14 males (32%), ratio 2.12: 1 ] were in the age range of 40-76 years, majority (48%) in sixth decade. 4 had unilateral and 40 (91%) with bilateral involvement. 41 left and 43 right knees were affected. Of 44 , 12 were diabetic, 12 obese, 10 had cardiovascular disease and 19 had no co-morbidity. 67% obese patients  were female. Of 84 knees, classified according to Kellgren & Lawrence  classification,  23 had grade 1 OA , 33 (39%) grade 2,28 grade 3: grade 4 was excluded. Grade 2 OA was the commonest  in both males and females . At the time of presentation and later two third patients  took analgesics – NSAID’s or opioids . After insole prescription, 5 patients reported an average usage of 2-4 hours/day, 39 (88.6%) used for 4-6 hours /day. Increased compliance to wearing shoe insoles was observed with increasing severity or grade of OA.

The mean WOMAC score at presentation was 39.36 , at 2 months follow up 35.83, at 4 months – 33.17 and at 6 months – 31.15 ( p= < 0.0001). It was statistically significant and indicated significant decrease in mean WOMAC score  at successive follow ups


Knee OA, a disabling disease, is commonly associated with significant loss of functional independence and impairment in quality of life. Economic impact of OA knee is an ever growing problem for health care systems and professionals in routine practice as well as during disaster management [10]. Non pharmacologic conservative interventions in the form of orthotics e.g. shoe insoles are gaining world- wide acceptance  as first line of approach to management.

Shoe insoles have been commonly prescribed for patients with diabetic foot problems, plantar fasciitis etc. Insoles made of different materials like latex foam, plastazote (polyethylene), cork, dynafoam, orthofelt (cotton and wool), spenco (neoprene sponge), PPT (firm foam), Molo (latex, jel, cork combination) have been studied in depth and compared [07,1 2]. Historically microcellular rubber footwear had been prescribed for patients with  Hansen’s disease. Studies evaluating pressure measurement and other aspects are available [09]

We report the first time usage of microcellular rubber shoe insoles in knee OA management. WOMAC score was higher in obese patients than in non obese. WOMAC score rose higher with increasing severity of OA. After  microcellular rubber insole utilization WOMAC score decreased in all 3 grades of OA during subsequent follow ups. It indicated relief in pain, improvement in range of motion, activities of daily living and quality of life.


10 mm thick shoe insoles made of microcellular rubber are a promising new orthotic entrant in management of knee OA. By virtue of being  simple, safe, easily available, compliable and economic they meet the requirements of an ideal orthotic therapy. They  will, hopefully, prove a boon for the patients as well as health care professionals and others in developing countries, especially  when required for a large number of patients e.g. during disaster management


1. Baker K , Goggins J , Xie H , Szumowski K , LaValley M , Hunter DJ , Felson DT : A randomized cross over trial of a wedged insole for treatment of knee OA : Arthritis Rheum : 2007 : 56 (4) : 1198 – 1203
2. Bellamy N : Pain assessment in osteoarthritis : Experience with WOMAC osteoarthritis index : Semin Arthritis Rheum : 1989 : 18 : 14 -17
3. Bennell K , Bowles KA , Payne C , Cicuttini F , Williamson E , Forbes A , Hanna F , Davis –Tuck M , Harris A , Hinman RS : Lateral wedge insoles for medial knee osteoarthritis : 12 month randomized controlled trial : BMJ: 2011: 342: 2912
4. Dieppe PA : Recommended methodology for assessing the progression of osteoarthritis of hip and  knee joints :Osteoarthritis cartilage : 1995 : 3:73 – 77
05. Hinman RS , Bennell K L : Advances in insoles and shoes for knee osteoarthritis : Current Opinion in Rheum: 2009 : 21: 164 – 170
6. Kellgren JH , Lawrence JS :Radiological assessment of osteoarthritis : Ann Rheum Dis : 1957: 16: 494 – 502
7. Leber C , Evanski PM : A comparison of shoe insole materials in plantar pressure relief : Prosthet Orthot Inter : 1986 : 10 (3) :135 – 138
8. Ledingham J , Regan M , Jones A , Doherty M : Radiographic patterns and associations of osteoarthritis of the knee in patients referred to hospital : Annals of Rheum Disease : 1993: 52: 520 – 526
9. Linge K  : A preliminary objective evaluation of leprosy footwear using in- shoe pressure measurement : Acta Orthop. Belg.: 1996 : 62 (supple. 1 ) :18 -22
10. Prakash J S, Deolalikar S, Prakash J, Thomas M, Singh D, Choudhary K : Disaster Mitigation & Capacity Development : Need for Specialized Preparedness [following December 26, 2004 Indian Ocean Tsunamis]. WebmedCentral Disaster Medicine : 2013 :  4(7):  WMC004336
11. Scott D : Osteoarthritis of hip : Clin Evid : 2009: 06: 1122         
12. Viswanathan V , Sivagami M , Saraswathy G , Gopalkrishna G , Das BN , Seena R , Ambadi R : Effectiveness of different types of footwear insoles for the  diabetic neuropathic foot : Diabetes Care : 2004 : 27 (2) :474 - 477
13. Yaron B , Yiftah B , Yuval R , Benedict S , Halperin N : A treatment applying to biomechanical device to the feet of patients with knee osteoarthritis results in reduced pain and improved function : BMC Musculoskeletal disorders : 2010 : 11:179

Source(s) of Funding

Self funded

Competing Interests


2 reviews posted so far

Review of the article on orthotics in OA knee.
Posted by Mr. Sanjay S Deo on 21 Feb 2014 07:52:27 AM GMT Reviewed by WMC Editors

Microcellular Rubber Insole in Management of Knee Osteoarthritis
Posted by Dr. Sumit Arora on 17 Feb 2014 08:01:40 AM GMT Reviewed by WMC Editors

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