Effect of forefoot rocker sole angle on plantar pressure distribution Trent Salkavich, B App Sc (Pod) Joshua Burns PhD, B App Sc (Pod) Hons Lindy Begg, Dip Pod Caleb Wegener, B App Sc (Pod) Hons IS IT AVERAGE OVER THE WHOLE GAIT OR IS IT PEAK PLANTAR PRESSURES

Definition: Forefoot Rocker Sole Shoe Pressure relieving intervention for the forefoot – prevent ulceration and re-ulceration. Contoured platform that controls joint motion by rocking the foot from heel strike through toe-off in the sagittal plane Walking is achieved by the contour of the rocker bottom forcing the foot to ‘rock’ or ‘tip’ forward when body weight passes over the fulcrum of the shoe. Change to point form

The Forefoot Rocker Sole The forefoot rocker sole reduces plantar pressure in the insensate forefoot during gait (Wei-Li et al, 2004) however the relationship between rocker gradient and plantar pressures remains unclear. Examined 4 different offloading conditions on a patient and their affect on ppp

Case Study Aim To assess the effect of different forefoot rockers on peak plantar pressures in a patient with a history of forefoot ulceration Angle of rocker and its effect on plantar pressures

Case Study Medical Hx 56 year old female School teacher Insulin Dependent Diabetes Mellitus – 1985 BMI: 27.5 Hyperlipidemia Palpable bilateral dorsalis pedis and tibialis posterior pulses PPG - R130, L 178 Sensory neuropathy Presented with osteomyelitic ulcer L 1st MPJ, causal pathway- untreated callous Present 10 weeks until healed Foot type Cavoid, Foot Posture Index; R -7, L -6 Plantarflexed 1st MPJ’s bilaterally Increased 1st MPJ stiffness bilaterally Mild hallux abducto valgus bilaterally

Methods 15˚, flexible sole, without Thanner™ 4 different conditions were measured : 15˚, flexible sole, without Thanner™ 15˚, flexible sole with Thanner™ 15˚, rigid sole, with Thanner™ 17˚, rigid sole, with Thanner™ Plantar foot pressures were measured using Novel Pedar System™ whilst the patient walked 2 lengths of a 10 metre flat walkway. Peak plantar pressures were measured Measurements were taken consecutively 3 different variables, gradient of forefoot rocker, sole flexibility, and with or without Moulded accomodative device (thanner).

Test 1: 15˚, flexible sole, without Thanner™ Conditions Original prescribed footwear 7 weeks old Standard 15˚ rocker flexible sole No moulded accomodative orthoses (Thanner™)

Test 1: 150, flexible sole, without Thanner™

Test 2, 15˚, flexible, Thanner™ Conditions Standard shoe 15˚ rocker Flexible sole Thanner™ Shoe condition then new slide with results

Test 2 -15˚ , Flexible , Thanner™

Test 3 15˚, rigid, Thanner™ Conditions Rigid sole 15˚ rocker Thanner™

Test 3 - 15˚, rigid, Thanner™

Test 4 - 17˚, rigid, Thanner™ Conditions 17˚ rocker Rigid sole

Test 4 - 17˚, rigid, Thanner™

Pressure Results PRESSURE kPa Flexible, 15˚ Flexible, 15˚ Rigid, 15˚ WHAT IS REGARDED AS A SAFE PRESSURE? Conditions 1-3 resulted in very similar high peak plantar pressures however an increase in only 2 degrees gradient of the forefoot rocker significantly decreased peak plantar pressures. Based on these results the most important variable was not the thanner or the sole rigidity but the gradient of the forefoot rocker Flexible, 15˚ Flexible, 15˚ Rigid, 15˚ Rigid, 17˚ CONDITION

Results A 2˚ increase in forefoot rocker gradient from 15˚ - 17˚ lead to a 26% reduction in forefoot plantar pressure.

Discussion Additional forefoot rocker angle can assist to significantly reduce peak plantar pressures and should be considered when prescribing footwear. ‘Standard’ orthopaedic rocker shoe has a 15˚ forefoot rocker gradient. This case study sets a basis for further research involving rocker gradient and forefoot pressure reduction.

Acknowledgements Pierre Marrion – Footwear That Fits Pty Ltd Dr Josh Burns Ms Lindy Begg Caleb Wegner