Current Concepts In Offloading Diabetic Foot Ulcers

Author(s): 
Ryan H. Fitzgerald, DPM

Is Total Contact Casting Still The Gold Standard For Offloading DFUs?

   There are numerous offloading modalities available to the clinician. These vary in complexity and cost. However, each device follows the basic premise to reduce both the vertical and shear forces across the wound site in order to allow for wound healing. Of significant importance to all of these devices is patient adherence as offloading devices only work if patients are indeed wearing them. It is vital that the physician impress upon the patient the necessity of continued adherence in the use of offloading devices. Three of the most commonly utilized modalities are the total contact cast (TCC), removable cast walker (RCW) boots, and the instant total contact cast (iTCC).

   Long considered the gold standard for offloading of the lower extremity, the TCC reduces plantar pressures while allowing ambulation. The contact nature of the cast allows for even distribution of pressure away from the ulcer site, which facilitates healing. An abundance of literature demonstrates the efficacy of TCC.16,17 This is largely due to TCC forcing the patient adherence with offloading.16,17 Despite the benefits of TCCs, these casts are cumbersome to the patients and can be difficult and time consuming to apply.

   More recently, TCC modifications have been developed to increase the speed and efficiency of applying these devices. The TCC-EZ (MedEfficiency) is a product that provides the offloading potential of traditional TCC while significantly increasing the speed and efficiency of application.

   One study demonstrated that application time for the TCC-EZ was 75 seconds in comparison to 452 seconds (7 minutes and 32 seconds) for application of a traditional TCC.17 Proponents for this product relate that utilization of the TCC-EZ significantly reduces traditional barriers to TCC usage by reducing the learning curve in TCC-EZ placement and increasing the speed of application.

Can Removable Walking Boots Have An Impact?

   In light of the challenges posed by TCC application, many clinicians have opted to utilize RCW boots to offload their patients with DFUs. There is literature to suggest that RCW boots can provide plantar pressure reduction and there are now a number of devices on the market for this application. Notable devices are the DH Pressure Relief Walker (Ossur), the Conformer Boot (Bledsoe Brace Systems) and the AirCast XP Diabetic Walker (DJO).16-18

   The DH walker creates plantar pressure relief via removable shock-absorbing hexagons that offer specific ulcer offloading and a reduction of vertical and shear forces in the area of the wound. The Conformer Boot provides DFU offloading via a unique dual density foot bed that evenly distributes forces across the plantar aspect and sides the foot much like a traditional TCC. The XP Diabetic Walker utilizes an aircell-lined shell that maximizes plantar offloading, thus reducing vertical and shear stress while providing protection and immobilization.

   While these modalities are easy to apply and allow for easy removal to facilitate wound evaluation and debridement, each of these devices has a similar limitation. Since patients can remove the devices, they are limited in their effectiveness.

What About The iTCC?

   To address this issue, Armstrong and colleagues presented a randomized, prospective study that evaluated the use of “instant total contact casts” (iTCC) in comparison to TCC in the offloading of diabetic ulcerations.19 The iTCC device is a removable walking boot, which has been modified to be “irremovable” via wrapping with a cohesive bandage. The thinking is the modification would increase patient adherence while maintaining the overall benefits of RCW boots, which include ease and speed of application.18

   This study found that healing rates in patients with lower extremity ulcerations were 80 percent in the iTCC group and 74 percent in the TCC group. These findings suggest that modification of standard RCW boots to increase patient adherence with pressure offloading may increase the proportion and rate of healing of DFUs with greater efficiency of application than traditional TCCs.19

Comments

I am surprised Dr. Fitzgerald omitted mention of the VACOcast Diabetic Foot line of ulcer offloading devices (www.vacodiaped.com, Framingham, MA). This boot is an RCW that incorporates a vacuum beanbag for a more "total contact" fit and it comes with an optional "locking seal" that makes it an iTCC without having to jerry-rig with a cohesive bandage. It is closer to a TCC than alternatives.

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