Increased aeen9on. The biomechanics of the diabetic foot and the clinical evidence for offloading and footwear. Sicco A.

Transcription

1 The biomechanics of the diabetic foot and the clinical evidence for offloading and footwear Increased aeen9on Sicco A. Bus, PhD Senior inves9gator and Head Human Performance Laboratory Academic Medical Center, Department of Rehabilita7on, University of Amsterdam, Amsterdam Global burden Ground reac9on force q 415m people with diabetes worldwide q 50% will develop peripheral neuropathy q 19-34% will have a foot ulcer q Strong risk factor for infec9on & amputa9on q 85% of amputa9on preceded by a foot ulcer q Reduced pa9ent mobility and quality of life q Enormous costs: average per ulcer: Force that the ground exerts on the body as a consequence of the effect of gravity Interpreta9on of pressure Interpreta9on of pressure Pressure is the cri9cal quan9ty that determines the harm done by the force Paul W. Brand Healthy foot Diabe9c foot Bauman JH, Girling JP, Brand PW. J Bone Joint Surg Br. 1963; 45: Bauman JH, Brand PW. Lancet. 1963; 23;1:

2 Pressure measurement E9ology: elevated plantar pressure Pressure and risk of ulcera9on Pressure and risk of ulcera9on Lavery et al. 1998; Arch Intern Med 158: ; n=225. Pham et al., 2000; Diabetes Care 23:606-11; n=248 Frykberg et al., 1998; Diabetes Care 21:1714-9; n=251 Monteiro-Soares et al., 2012; Diabetes Metab Res Rev 28: Ulcer recurrence from unrecognized repe99ve stress Factors in ulcera9on Nonulcera9ve lesion OR [95%CI: ] Pressure (normal and shear) (barefoot and in-shoe) Disease factors (e.g. neuropathy, PVD) In-shoe PP <200kPa + adherence >80% OR 0.43 [95%CI: ] Foot ulcer Varia9on in daily step count OR 0.91 [95%CI: ] Physical ac9vity (cumula9ve stress) Foot ulcer Pa9ent behavior (adherence to treatment) correctly classified = 76% Barefoot peak pressure OR 1.11 [95%CI: ] Waaijman et al., 2014; Diabetes Care 37: Bus et al., DMRR 28:S54-9 2

3 Causes of high foot pressure Claw toe deformity Abundant callus Claw toe deformity Equines foot Sub-MTH tissue changes Limited joint mobility Charcot deformity Partial foot amputation Prominent MTHs Plantar fascia changes Inadequate footwear Bus et al., Diab Care Bus et al., J. Biomech. Charcot deformity Offloading techniques Armstrong and Lavery, 1998; JBJS Offloading the foot ulcer TCC and would isola9on Custom Total Contact Cast Petre et al., 2005; Diabetes Care 28:

4 Pressure relief (offloading) OFFLOADING Guidance and systematic review Clinical efficacy in ulcer CLINICAL EFFICACY Guidance healing and systematic review Bus Plast Reconstr Surg, DOI: , S179-S187 Bus Plast Reconstr Surg, DOI: , S179-S187 Guidance and systematic review MAIN RECOMMENDATION Guidance and systematic review CASTING AND PREFABRICATED HEALING DEVICES To heal a neuropathic plantar forefoot ulcer without ischemia or uncontrolled infec7on in a pa7ent with diabetes..offload with a non-removable knee-high device with an appropriate foot-device interface GRADE Recommenda9on: Quality of Evidence: Strong High Bus et al., 2016; Diabetes Metab Res Rev 32(Suppl. 1): OTHER RECOMMENDATIONS Guidance and systematic review Ulcer recurrence CASTING AND PREFABRICATED HEALING DEVICES When a non-removable knee-high device is contraindicated or not tolerated by the pa7ent. Ulcer incidence in diabetes: 2% annually Ulcer incidence in diabe9c neuropathy: 7.5% annually Ulcer recurrence incidence: 30%-40% in first year.consider offloading with a removable knee-high walker with an appropriate foot-device interface when the pa9ent can be expected to be adherent to wearing the device GRADE Recommenda9on: Quality of Evidence: Weak Moderate Bus et al., 2016; Diabetes Metab Res Rev 32(Suppl. 1): AbboE et al., 2002; Muller et al., 2002; Pound et al., 2005; Bus et al.,

5 Custom-made footwear Biomechanical efficacy 16-37% pressure relief 29-52% pressure relief 36-39% pressure relief Van Schie et al., 2000; Foot Ankle Int. Bus et al., 2004 Clin. Biomech. Praet and Louwerens, 2003; Diab Care Guldemond et al., 2007 Clin. Biomech. Custom-made footwear characteris9cs offloading efficacy Characteris+c in ini+al footwear design Prevalence Included number of shoe pair 175 Fully- / semi- custom-made footwear 86% / 14% Trans-metatarsal bar (% of insoles) 12.9 % Metatarsal pad (%) 9.4 % Addi9onal medial arch support (%) 8.8 % A combina9on of above elements (%) 8.8 % None of above elements (%) 60.1 % Top cover of Plastazote 57.7% Top cover of leather 35.7% Top cover of other material (mostly PPT) 6.5% In-shoe peak pressure efficacy Efficacious footwear: peak pressure < 200 kpa 24% 79% 29% 95% 62% Overall Midfoot MTH Toes PUL Arts et al.; Diabe9c Med (6):790-7 Arts et al., 2012; Diab. Med. 29: Offloading improvement Offloading improvement 470 kpa 413 kpa 385 kpa 315 kpa Adjus9ng pivot point Local removal of material Local soxening of material Replacement top cover MT pad or bar q 35 loca9ons (in 23 pa9ents) with peak pressure > 200 kpa q Successful improvement: >25% relief or pressure <200 kpa q Peak pressure from mean 303 to 208 kpa in a mean 1.6 rounds q Mean pressure relief: 30.2%, range: 18-50% (i.e. 100% success) Bus et al., 2011; Diabetes Care 34: Bus et al., 2011; Diabetes Care 34:

6 Offloading improvement modifica9ons (single) Maximal Peak Pressure (kpa) n = 85 pa9ents Baseline Post modifications % -21% -15% >200 kpa (N=27) <200kPa (N=49) Previous Ulcer location Highest pressure (N=123) Second highest pressure (N=79) Region Of Interest Type of modifica+on N Target Pressure pre Pressure post Replacement of top cover of insole 154 Various 250 (50) 213 (44) (11.4)* Leather to 3mm Plastazote 31 Various 236 (73) 200 (72) (11.8)* Leather to 3mm Plastazote + 3mm PPT 12 Various 265 (100) 207 (62) (17.3)* Renewal of worn Plastazote 121 Various 222 (60) 195 (48) (12.5)* Local removal of material in insole 145 Various 253 (48) 232 (54) -8.3 (14.1)* Local cushioning in insole 92 Various 270 (62) 224 (58) (16.4)* Addi9on of a pad to insole 39 MTH /hallux 258 (48) 221 (50) (15.2)* Addi9on of a trans-metatarsal bar 30 MTH (79) 268 (72) (11.0)* Addi9on of a medial arch support 26 MTH (50) 239 (53) -6.7 (11.3)# % difference with pre-modifica9on, # p<0.05; * p<0.001 % Waaijman et al., 2012; Diab. Med. 29: Arts et al., 2015; Diabe7c Med 32(6):790-7 modifica9ons (combined) Offloading-effect matrix (single modifica9ons) Type of modifica+on N Target Pressure pre Pressure post Replacement top cover + local removal 58 Various 260 (54) 212 (52) (13.2)* Replacement top cover + cushioning 67 Various 271 (66) 209 (55) (13.3)* Replacement top cover + addi9on pad 24 MTH/hallux 281 (59) 238 (53) (10.3)* Replacement top cover + addi9on bar 52 MTH (56) 212 (51) (14.6)* Replacement top cover + reposi9on pad/bar 25 MTH (66) 210 (48) (8.7)* Addi9on trans-metatarsal bar + removal 13 MTH (108) 235 (70) (15.8)# Addi9on pad + local cushioning 16 MTH (30) 209 (47) (15.4)* % difference with pre-modifica9on, # p<0.05; * p<0.001 % Region Local removal material Local Replacement MT soaening of top layer pad Transmetatarsal bar Medial arch support Insole rocker Outsole Reposi+on rocker pad / bar Hallux -7.0* -8.9* -7.3* * -7.6* -1.6 Dig 2-3 NA NA -4.3* +9.0* Dig 4-5 NA NA -3.9* * +9.1 MTH 1-7.4* -13.9* -7.0* * -8.0* * MTH * -16.2* -12.2* -7.7* -9.7* * -5.5* -9.8 MTH 4-5 NA NA -7.1* -6.8* -8.4* +6.2* Midfoot medial NA NA -10.2* * Midfoot lateral NA NA -10.4* -6.8* % difference with pre-modifica9on, p<0.05 Arts et al., 2015; Diabe7c Med 32(6):790-7 Arts et al., 2015; Diabe7c Med 32(6):790-7 Offloading-effect matrix (combined modifica9ons) Efficacy in ulcer preven9on Region Local removal material Replacement of top cover insole + Local soaening MT pad Transmetatarsal bar Reposi+on pad /bar Hallux -16.8* -8.9* * Dig 2-3 NA NA * +4.7 Dig 4-5 NA NA * MTH * -20.0* -12.6* -18.3* -10.1* MTH * -21.0* -17.2* -24.3* -14.1* MTH 4-5 NA -26.6* -12.3* -19.0* -6.5* Midfoot medial NA NA -7.5* * Midfoot lateral NA NA -12.4* * % difference with pre-modifica9on, p<0.05 Arts et al., 2015; Diabe7c Med 32(6):

7 Modification Modification Modification Recent mul9center footwear trials Fully custom-made footwear 470 kpa 413 kpa 385 kpa 315 kpa Custom-made insoles in custom-made shoes Pa9ent inclusion Study flow Inclusion criteria q Diabetes mellitus type 1 or 2 q Loss of protec9ve sensa9on q Recently healed plantar foot ulcer (<18 months) q Prescrip9on of fully custom-made or semi-custom-made footwear Bus et al., Diabetes Care 36: Enrollment Analysis Follow-up Alloca9on 85 allocated to interven9on 86 allocated to control Each 3 months 6 lost to follow-up 2 pa9ents died 4 withdrew par9cipa9on 85 analyzed for ulcer recurrence in 18 months (ITT analysis) Ini9ally assessed (N=267) Baseline assessment (N=192) 171 Randomly assigned Each 3 months 4 lost to follow-up 2 pa9ents died 2 withdrew par9cipa9on 86 analyzed for ulcer recurrence in 18 months (ITT analysis) Bus et al., Diabetes Care 36: Baseline characteris9cs Instrumenta9on Interven+on Control N Male gender 82.3% 83.5% Age (years) 62.6 (10.2) 63.9 (10.1) BMI (kg/m 2 ) 30.9 (6.4) 30.4 (4.9) Type 2 diabetes 67.1% 75.6% Diabetes dura9on (years) 19.9 (15.1) 14.7 (11.2) * VPT (V) 44.5 (10.7) 45.1 (9.9) PAD (Present / Absent) 24 / / 55 Foot deformity level (%) (no/mild/moderate/severe) 17/43/26/15 16/41/26/17 Barefoot peak pressure (kpa) 896 (290) 954 (278) Plantar pressure measurement (Emed-X, Pedar-X) use (@monitor) Daily step count (StepWatch) Bus et al., Diabetes Care 36: Bus et al., 2012; Arch Phys Med Rehabil 93:

8 Adherence Adherence over the day Adherence (%) Daily step count (steps) Overall (N=107) 71 ± ± 3494 At home (N=79) 61 ± 32* 3959 ± 2594* Away from home (N=79) 87 ± ± 2507 Waaijman et al. 2013; Diabetes Care 36: Waaijman et al. 2013; Diabetes Care 36: Ulcer recurrence prescrip9on Inten9on-to-treat: 11% Adherent pa9ents (>80% footwear use): 46% Bus et al., Diabetes Care 36: Custom-made inserts in standard extra-depth diabe9c footwear Pressure and shape-based insoles Pa9ent inclusion Flexible shoe Inclusion criteria: q Diabetes mellitus type 1 or 2 q Loss of protec9ve sensa9on q One recently healed plantar MTH ulcer (< 4 months) q Peak barefoot pressure at index ulcer >450 kpa Rocker shoe Owings et al., 2008; Diabetes Care 31: Ulbrecht et al., 2014; Diabetes Care 37:

9 Study flow Baseline characteris9cs Enrollment Analysis Follow-up Alloca9on 79 allocated to interven9on 71 allocated to control 8 lost to follow-up 12 withdrew par9cipa9on 66 analyzed for ulcer recurrence and minor lesion at MTH in 15 months (ITT analysis) Assessed for eligibility (n=185) 150 Randomly assigned 66 received allocated interven9on 64 received allocated interven9on 4 lost to follow-up 17 withdrew par9cipa9on 64 analyzed for ulcer recurrence and minor lesion at MTH in 15 months (ITT analysis) Interven+on Control N Male gender 75.8% 81.3% Age (years) 60.5 (10.1) 58.5 (10.7) BMI (kg/m 2 ) 32.2 (7.1) 31.4 (5.5) White race 83.3% 79.7% Living alone 24.2% 26.6% Barefoot peak pressure (index ulcer) 946 (266) 967 (233) Barefoot peak pressure (any site) 1109 (173) 1085 (191) Ankle-Brachial index 1.05 (0.16) 1.13 (0.18) Foot deformity index 28.4 (14.6) 28.9 (17.3) Ulbrecht et al., 2014; Diabetes Care 37: Ulbrecht et al., 2014; Diabetes Care 37: Ulcer recurrence 9.1% ulcer Guidance and systematic review 25.0% ulcer P=0.007 Hazard ra9o: 3.4 Barefoot peak pressure was only variable that predicted ulcer outcome! Ulbrecht et al., 2014; Diabetes Care 37: Guidance Modern approach to footwear design FOOTWEAR AND ORTHOSES To prevent a recurrent plantar foot ulcer in an at-risk pa7ent with diabetes.. 1. Prescribe therapeu9c footwear with a demonstrated plantar pressure-relieving effect: <30% compared to standard of care therapeu9c footwear 2. Mo9vate the pa9ent to wear the footwear, including when at home GRADE Recommenda9on: Quality of Evidence: Strong Moderate Systema9c Science-based Data-driven Evidence-based 9

10 Implementa7on of plantar pressure measurement for evalua7on and improvement of the quality of specialmade footwear for diabe7c pa7ents. In-shoe pressure measurement It provides direct feedback on the effect of the shoes It provides a way to op9mize footwear for the pa9ent at risk It provides a way to minimize errors in footwear outcome It gives the prescriber and shoe technician confidence that you made the right shoe It provides a way to communicate with your pa9ent It gives informa9on about possible causes when foot problems recur Take-home messages q Elevated mechanical pressure causes foot injury in diabetes q These high pressures can be effec9vely reduced and ulcers most effec9vely healed using non-removable offloading devices q Custom-made footwear is oxen not yet op9mal at delivery and adherence to its use is poor q Low foot pressure and high adherence are the key to clinical success q A systema9c scien9fic-based data-driven approach to footwear design and evalua9on proves most effec9ve Foot square, AMC s.a.bus@amc.uva.nl 10