Roy H. Lidtke Assistant Professor of Internal Medicine, Section of Rheumatology Rush University Medical Center, Chicago, Illinois

Roy H. Lidtke Assistant Professor of Internal Medicine, Section of Rheumatology Rush University Medical Center, Chicago, Illinois

Osteoarthritis (OA) is the most common form of lower extremity arthritis 1 Close to 30 million people in the U.S. suffering from this debilitating disease. 1 One third of all adults over age 65 have osteoarthritis, with the medial knee the most affected joint component. 2-4 1.Lawrence RC, Felson DT, Helmick CG, et al. Arthritis Rheum 2008;58(1):26-35. 2.Dillon CF, Rasch EK, Gu Q, Hirsch R. J Rheumatol 2006;33(11):2271-2279. 3.Jordan JM, Helmick CG, Renner JB, et al. J Rheumatol 2007;34(1):172-180.

More than 650,000 total knees are done in the US (2009) Osteoarthritis cost more than $128 Billion Annually

OA is a naturally progressing disease state. Kellgren-Lawrence I, II, III, IV Logic suggest that treatments should follow this natural progression.

Onset of physician-diagnosed OA 1990 s average: 69 years 2010 average: 56 years 40% of all knee replacements are done under the age of 65 Research is showing that OA starts at age 20-30 Sources: http://www.arthritistoday.org/news/knee-osteoarthritis-on-rise163.php http://www.arthritistoday.org/news/knee-replacements-increase-younger-patients175-2.php 5

Diagnosis and treatment at a younger age Treatment can extend over a longer period of time (20+ years) Until there is a cure the goal of treatment is to delay time to total knee replacement 6

Narcotics Lateral Wedges Orthotics Shoe Shoe Wear Brace Support Off-Loading Brace TENS NMES Cold Therapy 7

Research is showing the foot is a major originating factor for lower extremity pain. The forces from the ground have to come through the foot to the knee, hip and spine

Ground forces fall to the inside of the knee Produces an twisting force on the knee The soft tissue of the knee counteract this force

Footwear has a significant effect on lower extremity joint loads. 1,2 Walking barefoot significantly decreases peak knee loads compared to walking with standard walking shoes. 3 These results suggested a potential biomechanical advantage of natural foot mobility for lower extremity joint loading. 1. Shakoor, N., Lidtke, R. H., and Block, J. A. Arthritis Rheum 54:2923, 2006 2. Shakoor N, Sengupta M, Foucher KC, et al. Arthritis Care Res 2010;62(7):917-923. 3. Shakoor N, Block JA. Arthritis Rheum 2006;54(9):2923-2927.

Walking more apprehensive?

Better Proprioception?

Most shoe companies were focusing on stability. Lateral Heel Flares Standard Heel Lift Rigid Heel Counter Foxing on the Upper Dual Density Midsole Rigid Outsole

Key Joint Segments Each Phase Outsole Cuts force or allow for motion Want the shoe/foot to move in a specific direction at specific times

3.2 Knee Adduction Moment (%BW*HT) 3.1 3 2.9 2.8 2.7 2.6 2.5 Clog Stability Flat Barefoot DRC/OA p<0.05

Gait analysis was repeated at 6,12, and 24 weeks 50 Subjects with radiographic (KL grades 2) and symptomatic (at least 30mm pain of 100mm scale while walking) medial compartment knee OA were randomized : 22 participants (13 women, mean age 55±7 years) were assigned to the mobility shoe 28 participants (21women, mean age 55±8 years) were assigned to the control shoe Baseline gait analyses were performed using an optoelectronic camera system and multi-component force plate in subjects' own shoes, study shoes, and barefoot. Subjects were instructed to wear the study shoes at least 6 hours/day for 6 days/week The peak knee adduction moment (KAM), a validated marker of medial compartment loading, was evaluated. An intent-to-treat analysis was performed with imputation of missing data using a hot deck method (Rubin, 1987). Both subjects and participants were blinded to treatment group Repeated measures analysis of variance compared the two arms and planned contrasts were used to further analyze the data and load reductions at various time points.

Knee Adduction Moment (%BW*Ht) control group experienced a 4% reduction (3.13±0.81 to 3.00±0.66 %BW*ht, p=0.361)

Knee Adduction Moment (%BW*Ht) 20% reduction in the KAM by 24 weeks (3.06±1.22 to 2.44±0.72 %BW*ht, p=0.002)

400 Womac Knee Pain Score 46% reduction over 6 months 350 300 250 200 150 100 50 0 Baseline 6 Weeks 12 Weeks 6 Months

Proximal tibial bone mineral density (BMD) serves as a marker for structural consequences of altered joint loading (Thorp et al, Bone 2006) Local bone mass increases with increased joint loads Local bone mass decreases with decreased joint loads

Medial Tibial BMD (g/cm2) 1.1 1 0.9 0.8 0.7 0.6 Medial Tibial Bone Mineral Density Change over Time 0 24 48 Time from Start of Intervention (weeks) Control Shoe Mobility Shoe

A 20% reduction in loads is very significant. The moments remained reduced even when the patients walked without the shoe and in their own shoe- suggest neuromuscular adaptation. Wearing a shoe caused a physiological change in the tibia. Patients did not want to give the shoes back. Patients immediately loved the shoes.