Offloading in four devices used in the treatment of plantar ulceration
- Benn Beuker (Diabetic Foot Unit, Dept of Surgery, Twenteborg Hospital, Almelo, the Netherlands)
- Prof. Patricia Price (Wound Healing Research Unit, School of Medicine, Cardiff University)
- Prof. Keith Harding (Wound Healing Research Unit, School of Medicine, Cardiff University)
- Eric Manning (Diabetic Foot Unit, Dept of Surgery, Twenteborg Hospital, Almelo, the Netherlands)
- Sjef van Baal (Diabetic Foot Unit, Dept of Surgery, Twenteborg Hospital, Almelo, the Netherlands)
- Dr. Robert van Deursen
Plantar offloading is an important intervention for treating diabetic foot ulcers. Four devices used in the Netherlands and the UK for treatment of diabetic foot ulcers were compared to study the offloading mechanism used in each device and the magnitude of the effects. Included were a custom molded insole shoe (CMI shoe), a soft-cast shoe with custom molded rigid cast sole (MABAL shoe), a bi-valved total contact cast (BTCC) and a pre-fabricated pneumatic walking brace (PPWB). A Lohman Shoecast sole was worn under the MABAL shoe and BTCC. The control shoe had a rigid flat insole made of EVA.
Sixteen healthy subjects walked at their preferred speed wearing the different devices on the right and the control shoe on the left. In shoe pressures were measured using a Pedar system. Gait analysis was performed using a Vicon system and two Kistler force plates. Peak pressure of the MTP1 area, medial midfoot impulse and total plantar impulse were determined and the integral of the vertical ground reaction force measured with the force platform was calculated.
MTP1 peak pressure was significantly reduced compared to the control shoe for all devices (p<0.01) but most of all for the BTCC. Load on the medial midfoot area was increased significantly for all devices (p<0.01) but most of all for the BTCC.
Compared to the control shoe, in shoe plantar impulse was significantly reduced by 11% in the CMI shoe, 26% in the MABAL shoe, 35% in the BTCC, and 28% in the PPWB.
Load transfer to the medial midfoot seemed to occur in the CMI shoe and MABAL shoe but most in the BTCC. Supporting the arch of the foot can effectively off-load the plantar surface. Substantial foot off-loading occurred in the BTCC and PPWB with weight transferred to the lower leg.