Diabetes and Orthoses Rob Bradbury Talar Made
Diabetes High prevalence disease 4-6% in UK (over 2.5 mill diagnosed and a further 0.5 ) 6+% in USA 40% in some parts of Middle East (may be higher in Indian Subcontinent 90+% Pima Indian Population
High Cost Disease 10+ % of UK NHS spend ( 15Bn+)per annum (Audit Commission 2009) Foot complications cost more than other complications combined (Foster et al 2000) In UK average bed stay for foot complications is 14 days (more than for any other admission) ( ed :Farris 1999) Average cost for Forefoot amputation in UK is 50000 Cost for below knee amputation is > 75000 (Counting the Cost Audit Commission 1998)
Causes Behind Foot Complications Major complications behind Diabetic Foot Problems Ischaemia Ulceration Poor Healing Infection Necrosis ( Edmunds & Foster 2000)
Neuro-Iscaemia Combination disease Loss of sensation including pain perception Damage Poor healing Infection Necrosis
Neuropathy Loss of sensation Damage Non healing Ulceration Continued Damage Infection Necrosis (Edmunds & Foster 2000)
Causes of Neuropathic Ulceration Loss of Sensation Loss of proprioception Biomechanical Changes
Normal Gait STANCE PHASE 65% Contact Period - heel strike to forefoot loading Midstance Period - forefoot loading to heel raise Propulsive Period - heel raise to toe off SWING PHASE 35% Acceleration Deceleration
CONTACT PERIOD Heel strike to forefoot loading Foot pronates around the subtalar joint Only time (stance phase) normal pronation occurs This absorbs shock & adapts foot to uneven surfaces Ground reaction forces peak Leg is internally rotating Ends with metatarsal heads contacting ground
MIDSTANCE PERIOD Forefoot loading to heel raise Foot stops pronating & starts supinating due to Tibialis posterior & Soleus contract And external rotation of the leg Other leg in swing phase all weight on one foot Vertical ground reaction forces decrease body is directly over foot Ends as heel leaves ground
PROPULSIVE PERIOD Heel raise to toe off Subtalar joint supination continues until just after toe off Leg continues to externally rotate Vertical ground reaction forces peak forefoot only bearing weight on this side Forces move from lateral to medial passing through the hallux First MPJ must function correctly for maximum efficiency Toes are loaded to stabilise MPJ s
Diabetic Gait
Contact period Very Characteristic Loss of deceleration at heel strike Tibialis Anterior affected (Abboud 2002) Posterior Tibialis effect reduced Pronation occurs rapidly
Midstance Period Foot continues to pronate Forefoot loading increases to maximum Metatarsal heads fully loaded
Propulsive Period Heel comes off the ground Metatarsal heads still fully loaded Foot is still pronated No lever effect available Apropulsive gait
The foot does not recover and remains pronated throughout the gait cycle. This gives the characteristic slap foot (Plank et al 2000)
Swing Phase Very little swing phase Foot is raised from the ground by anterior thigh muscles Very slow kadence High fatigue levels
Conclusion Characteristic Gait pattern Foot is pronated Remains pronated No supinatory recovery High pressures over metatarsal heads High value of force /time integrals
Treatments Over pronation is problem Increased time and forefoot pressure Control the pronation Use of suitable orthoses and materials Need Functional orthoses Cost Implications
Foot Orthoses Need to be Functionally corrective/controlling Control pronation Allow some resupination (where possible) Change force /time integrals
Early preventative treatment Prefabricated devices High quality Functionally corrective Highly effective Cost efficient Accepted for payment in USA when heat mouldable
References Counting the Cost Audit Commission Report 1998. The Management of the Diabetic Foot-Faris 4 th ed 1999 Managing the Diabetic Foot- Edmonds& Foster 2000 Prevention of Foot Ulceration in Diabetic Patients-The Way Forward-Dr R Abboud 2002 Effects of Range of Motion Therapy on Plantar Pressures of Patients with Diabetes Mellitus-Goldsmith et al 2002 Increased Plantar Pressure and Contact Time in Diabetic Neuropathy-Plank et al 2000 The Effect of Arch Height and Body Mass on Plantar Pressure-Schie & Bolton 2001 Effects of Foot Type Biomechanics and Diabetic Neuropathy on Foot Function- Song et al 1999 In Shoe Pressure Measurements in Diabetic Patients with At Risk Feet and in Healthy Subjects. Sarrow et al 1994 Analysis of Dynamic Forces Transmitted Through the Foot in Diabetic Neuropathy-Shaw et al 1998 Forefoot to Rearfoot Plantar Pressure Ratio is Increased in Severe Diabetic Neuropathy & Can Predict Foot Ulceration-Caselli et al 2002 The Role of Dynamic Plantar Pressures in Diabetic Foot Ulcers-Stress et al 1997 Relationship of Limited Joint Mobility to Abnormal Foot Pressures and Diabetic Foot Ulceration-Fernando et al 1991