CENTERCENTER OF PRESSURE ON OF PRESSURE ON DIABETIC SUBJECTS WITH DIABETIC SUBJECTS WITH

ROCKER SOLE SHOESROCKER SOLE SHOES

Reporter: I-Wei LinAdvisor: Sai-Wei Yang

Outline

• Introduction

• Hypothesis and assumption

• Material and method

• Preliminary result

• Future work

DM foot problem

pressure

Shear force callusulceration

necrosisamputation

DM footneuropathy 、vasculopathy

Rocker shoes will often be prescribed for DM patient to prevent ulceration

Introduction of rocker shoe

• Apex of the rocker can be placed proximal to the site of ulceration, thus alleviating significant plantar pressures

• Rigid rocker sole reduces pressure and impact shock

MPJ ROCKER inhibits the demand for dorsiflexion of the toes MET-HEAD ROCKER reduces ground-reaction force

ANKLE JOINT ROCKER decreases ankle motion demand

HEEL ROCKER is used in conjunction with an increase of the heel pitch to shift weight forward

Literature review

• For the metatarsal heads: The best average rocker axis location was in the region of 55-60% of shoe length• For the toe: 65% of shoe length ↑shoes height, ↑shoes angle, ↑pressure

relief Schie et. al.,2000 Insatiability

• The axis from 55% to 70% of foot length, the load-bearing move from the heel to the medial region• Relief of peak pressure at the heel may be related to increase comfort with rocker soles Jun et.al. 2004 65%

• Mueller found an 11% reduction in step length with rocker sole use

• Peterson reported that heel impact loads were four times greater in rocker shoes than in athletic shoes

• Schaff et al. found peak pressures on the forefoot decreased medially and increased laterally, with significant changes in temporal parameters

• Xu et al. found changes in center of pressure (COP) locus related to the heel design of the rocker sole

Other literature review

Why use forefoot and heel rocker?

Cop velocity & Pressure time integral

5.0 5.44.0 5.0 5.8 6.6 6.8

4.8 3.8 3.4

0.91.5

1.20.8

1.01.0 0.9

1.91.6 1.8

0.0

2.0

4.0

6.0

8.0

10.0

SD

pressure-time integralsin masks_mean

Pressure-time integrals of DM

DM subjects shows greater PTI in heel and forefoot region

Design rocker shoe

Purpose of the study

• To investigate the effect of heel to toe rocker shoe with different apex locus for the DM subjects in pressure relief and Cop altering

• Hypothesis:– Heel-to-toe rocker soles will contribute to plantar

pressure relief and alter the gait pattern of DM subjects

Material and method• VICON motion system

– Marker set: Modified Helen Hayes

– Sampling rate: 120 Hz

• AMTI force plate– 3 force plates

– Sampling rate: 960 Hz

• Footscan– Synchronization with forcepla

te

– Sampling rate: 500 Hz

• Pedar

10 m

1.2 mforceplate

Material and method

• Conditions：– Level walking

– Barefoot– Shoes

• Baseline shoe(the flat sole without rockers)

• 55% rocker shoe

• 60% rocker shoe

• 65% rocker shoe

Informed consent and Questionnaire

Basic measurement: foot geometry range of motion

sensitivity

Plantar pressure

Motion capture

Barefoot55% rocker shoes 60% rocker shoes65%Rocker shoes

Assign randomly

Baseline shoes

Flow chart

Preliminary results

Subjects basic data

• Sex: Male 8； Female: 8

• Age:58.2 ± 7.2 y/o

• Height: 159 ± 5 cm

• Body Weight: 66.7 ± 15.5 kg

• BMI:26.1 ± 1.5 kg/m2

Cadence(Steps/min)

0

50

100

150

barefoot

baseline

55%

60%

65%

Cadence 106.56076 102.35 115.50484 112.5 113.5

barefoot baseline 55% 60% 65%

Rocker shoes increase in cadence

Walk speed(m/s)

0

0.5

1

1.5

barefoot

baseline

55%

60%

65%

walk speed 1.03 1.005 0.97 1.23 1.02

barefoot baseline 55% 60% 65%

Rocker shoes maintain walk speed

Pedar

Baselineshoes

Rockershoes

maximum force

-20

-10

0

10

20

Heel Mid foot M1 M2 M345 T1 T2-5

55% rocker

60% rocker

65% rocker

** *

* *

1. Maximum force and peak decrease in heel and forefoot region!2. Force increase in mid foot 3. 60% and 65% do not show a significant difference

peak pressure in masks

-8

-6

-4

-2

0

2

Heel Mid foot M1 M2 M345 T1 T2-5 55%

60%

65%

** * * *

Peak pressure decrease in heel and forefoot region, especially with 60% and 65%rocker shoes

contact area in mask

-5

0

5

10

Heel Midfoot

M1 M2 M345 T1 T2-5

55-base

60-base

65-base

pressure-time integrals

-2

-1.5

-1

-0.5

0

0.5

1

1.5

Heel Mid foot M1 M2 M345 T1 T2-5

55-base

60-base

65-base

Rocker shoe can decrease heel and most of forefoot region in

contact area.

Rocker shoe can decrease forefoot region in pressure time

integrals.

足底壓力量測參數

Peak pressureCenter of Pressure,COP

The load pathway (Gait line or center of pressure

COP)

CoP velocity & acceleration

T1 T2 T3

T4T5 T6

T7 T8

• Bare• Baseline• 55rocker• 60rocker• 65rocker

Conclusion

• In spatial temporal parameter, rocker sole increase in cadence but decrease in walk speed

• 60% and 65% rocker shoes show a great pressure relieve than 55% rocker shoes

• All rocker shoes will shift load-bearing to mid foot and increase mid foot contact area

• Effects of55% 、 60% and 65% rocker shoes are not consistent, the reason might be the pivot of 55% 的 rocker shoe is in the mid foot area and others are around 1 MTH

Conclusion• In Cop analysis ， V2(correspond to the ankle rocker

velocity of gait) decreased and didn't change in cadence and walk speed which means rocker shoes assist in propulsion and save the expenditure of ankle joint.

• 60% 、 65% heel-to-toe rocker shoes may apply to high plantar pressure in fore foot and heel region ； heel-to-toe rocker shoes do not fit for high risk of mid foot ulceration of DM patient (eg.Charcot foot deformity)

References• Wu, W. L., Rosenbaum, D., Su, F. C., (2004). The effects of rocker sole and

SACH heel on kinematics in gait. Med Eng Phys. 26(8):639-46. • Brown, l. D., Wertsch, J. J., Harris, G.F., Klein, J. , Janisse, D., (2004) Effe

ct of rocker soles on plantar pressures. Arch Phys Med Rehabil, 85:81-6. • Myers, l. K., A., Long, J. T., Klein, J.P., Wertsch, J. J., Janisse. D., Harris,

G.F.,(2005) Biomechanical implications of the negative heel rocker sole shoe: Gait kinematics and kinetics. Gait & Posture, In Press, Corrected Proof, Available online 21 November 2005

• Mueller, M.J., Strube, M.J., Therapeutic footwear: enhanced function in people with diabetes and transmetatarsal amputation. Arch Phys Med Rehabil 1997;78:952-6

• Mueller, M. J., Sinacore, D. R., Hoogstrate, S., and Daly, L., “Hip and ankle walking strategies: effect on peak plantar pressures and implications for neuropathic ulceration,” Arch. Phys. Med. Rehabil., vol. 75, pp. 1196–1200, 1994.

• Schie, l. C. V., Ulbrecht. J. S., Becker, M.B., Cavangh, P. R. ,(2000) Design Criteria for Rigid Rocker Shoes, Foot & Ankle International, 21:. 833-844

• Jun, I. S., Joo. C. J. P.,Park. S. B.,Oh. S. G., Lee. S. J., The relationship between peak plantar pressure and comfort using the rocker shoes

• Van Bogart J. J., Long J. T., Klein J. P., Wertsch J. J., JanisseD. J. and Harris G.F., (2005). Effect of the toe-only rocker on gait kinematics and kinetics in able-bodied persons.IEEE Trans Neural Syst Rehabil Eng 13(4):542-50.

• Vaughan. C. L., Davis B. L., O.Connor. J C., Dynamics of human gait. (1999). Kiboho Publishers

• W. Brand, "Management of the insensitive limb," Physical Therapy, vol. 59, pp. 8-12, 1979

• 蔡世澤台灣糖尿病照護現況與省思臨床醫學 2000; 45: 316-20

• 訂製矯正鞋之製作原理與方法研討會講義 Appendix B

• http://www.richeylab.com/Richey%20Lab%20Rocker%20Sole%20Overview.pdf