The Diabetic Amputee

The Diabetic Amputee - Promote & Protect

Diabetes the leading cause of non-traumatic Lower Extremity Amputation (LEA) in the US with 60% of all non-traumatic LEA occurring in diabetics[1]. From this, it is clear that a majority of the patient a Physical Therapist will see for amputee rehab have diabetes. It is important to note that Diabetes is a systemic disease that negatively affecting every system of the body. The Physical Therapist must be aware of the potential impact diabetes has on their patient, on their rehabilitation, and on their mobility goals after LEA. Not only will the Physical Therapist need to promote mobility, they must also protect the patient’s contralateral limb during mobility training.

Diabetics are 15 times more likely to undergo a LEA than non-diabetics. Furthermore, diabetics who have undergone a LEA have a 55% greater risk of death than non-diabetics. The risk of reamputation is greater in diabetics with the rate of major amputation of the contralateral limb is 11.6% at 1 year and 53.3% at 5 years[2]. With this in mind, protection of the diabetic amputee’s contralateral limb has more meaning. One study found that in diabetic patients have “an identifiable and potentially pivotal event, in most cases an episode involving minor trauma that caused cutaneous injury, preceded 69-80% of amputations”[3].

The primary goals of Rehab after LEA are to increase mobility, increase independence, and increase potential success with future prosthetic function. As with any patient, these goals to increase mobility may be at odds with the goal to maximize safety. However when working with the diabetic amputee, safety is of utmost importance as they are more susceptible to injury and tissue failure while increasing their mobility. This coupled with the knowledge that their healing rates are slower than non-diabetics, puts them at greater risk of significant postoperative complications.

Safety goals takes 2 main forms: 

  1. Prevent injury due to falls, and
  2.  prevent damage by reducing abnormal stresses on known compromised tissue (ie, the contralateral limb).

We will be promoting mobility and recovery while also protecting the contralateral limb.

Diabetes affects most if not all tissues in the human body, particularly affecting endothelial cellular tissue. It is believed that hyperglycemia is the primary cause of diabetic related complications. The current view is that hyperglycemia causes an increased formation of Advanced Glycation End products (AGEs) which in turn are the pathogenetic mediators of almost all diabetes complications, conventionally grouped into microangiopathies (nephropathy, retinopathy, and neuropathy) and macroangiopathies (cardiovascular, cerebral vascular, and peripheral vascular disease)[4].

AGEs also form in the joint capsule and tendons contributing to a decrease in ROM in the muscles and joints of diabetics. The formation of AGEs in the connective tissues causes increased rigidity, decreased compliance, and decreased extensibility. The AGEs act as molecular clue because of the chemical reaction glucose and proteins. This cross-linkage is irreversible. It is then imperative to work to maintain the diabetic amputee’s available ROM on the contralateral limb in effort to prevent loss of motion due to this irreversible process[5].

Transfer Training

While performing level surface transfer, the diabetic amputee is at risk of placing abnormal stresses on the contralateral limb by pivoting or spinning on their foot. This occurs when the diabetic amputee moves their body weight over their intact limb’s foot when it is planted on the ground. If the amputee does not adjust or reposition the foot during the transfer, the stress of the transfer is absorbed in the tissue of the foot. These rotational and shear forces can cause microtrauma to the tissue of the foot. The diabetic amputee is not aware of this increased stress or potential damage because there is often a decrease in protective sensation at the intact foot.

In order to prevent this from occurring, the PT should teach the diabetic patient to move slowly during the transfer and to move their body weight in smaller increments. It is important that they reposition their foot at each increment to accommodate for the movement of their body. Functional strength deficits in the diabetic amputee’s upper extremities may also affect their ability to move in smaller increments to the transferring surface. Therefore, it is important for the PT to assess and address any UE weakness in order to help this transfer technique to be successful.

Gait Training

Gait is the most potentially hazardous activity for the diabetic amputee. Although falls are a significant danger to the diabetic amputee; however, there is also an often overlooked danger of tissue damage at the contralateral limb. Unilateral gait, even with an assistive device, places greater demand on the intact limb. During gait training with the diabetic amputee, the Physical Therapist must be aware of the potential for abnormal stresses on the intact limb and intervene in order to mitigate these stresses. Again, it is important to note that the diabetic amputee’s tissue is less resilient and less able to tolerate this stress.

How the diabetic lifts their foot off the ground to initiate swing and how they land onto their foot at initial contact affects the amount of stresses placed on the contralateral foot during gait. Abnormally high stresses often occurs at initial contact or at the landing of the intact limb’s foot. If the landing of the intact limb’s step is hard and forceful, there will be an increased shear force placed on the foot. Observe if the diabetic amputee is doing a hopping action in order to bring their leg forward causing a hard, uncontrolled landing. This occurs if they are not strong enough to effectively lift their body weight with their UEs onto the assistive device.

As a pre-gait intervention, the PT should assess if the diabetic amputee is able to lift their body weight with their upper extremities onto the assistive device effectively. If not, UE strengthening should be an incorporated into the treatment plan. In this pre-gait phase, the PT can use this opportunity to teach or train the diabetic amputee on how to effectively and safely step with a soft landing. They may need to be shown the technique of lifting their body weight onto the assistive device and slowly lowering their weight onto their intact limb. This technique lessens the impact, as well as, lessens the shear force that occurs with a sudden halt of the forward momentum of the foot when contacting the floor.

During all gait training sessions, regardless of the assistive device used, the PT must insure that the patient is able to have a controlled, soft landing with each step. At any point the patient gets too tired or weak to accomplish this, the patient must be allowed to rest. It is imperative that the goal of gait distance does not trump the goal of contralateral limb protection. If endurance is an issue, then this must also be addressed by the rehab team.

Fall Prevention

Falls after amputation are high. This is inherent in the altered mechanics of gait as there is a loss of bipedal gait and double-limb stance phase. Even with gait assisted with an assistive device, there is a loss of double-limb stance time. Also at some point during the gait cycle, there will be a period of limited BUE support causing an increased reliance on the intact limb to safely and effectively hold the body in an upright posture. Safe, unilateral gait with an assistive device requires effective proprioception, ROM, and strength of the contralateral limb which are all likely compromised in the diabetic amputee.

There are many factors that must go into deciding what assistive device to use with gait. Whereas with a non-diabetic amputee, the PT may choose to use crutches for gait training due to the increased ease and efficiency with gait;use of crutches for a diabetic amputee may place them at increased risk of fall and injury to their intact limb. Safety must prevail in choosing which assistive device to use.

Standard Walker versus Rolling Walker

One may opt to use a standard walker rather than a rolling walker due to the increased stability of the walker itself. This may be a good choice for the diabetic amputee who has limited ability to walk household distances (>10 meters) and needs the walker to be very stable when performing the lift technique for gait (to allow the soft, controlled landing at initial contact). However, the lifting action of the walker and the potential of weight displacement posteriorly needs to be considered. Being able to keep the walker in contact with the ground, may actually increase the diabetic amputee’s safety during gait. Also, use of a standard or ‘pick-up’ walker is more physically taxing on the amputee which may limit its usefulness.

Walker versus Crutches

It takes a good bit of unilateral balance to effectively and safely use crutches; therefore, the diabetic amputee must have good balance, no sensory loss, or strength deficits in their intact limb to be successful - and not at risk of falling.

Along with the known increased fall risk after a LEA and the increased potential for loss of balance on the intact limb, the PT must also consider how the diabetic amputee may fall. With crutches people are more likely to lose their balance forward or backward rather than side to side. If they do lose their balance, they typically will reach out with their ‘swing phase’ leg to catch their balance. For a transtibial amputee, the residual limb is often the limb that they reach out with - causing a fall onto the distal end of of their residual limb. It is interesting to note that when a transfemoral amputee falls with crutches, they tend to flex or tuck their residual limb causing an impact on their hip or buttock, but not often on the distal end of their residual limb. Therefore, not only does a walker give the diabetic amputee a more stable base to walk and lessens their risk of falling, it also lessens the risk of direct injury to the residual if a fall were to occur.

References

  1. CDC report finds large decline in lower-limb amputations among U.S. adults with diagnosed diabetes 2012
  2. Izumi, Y., Satterfield, K., Lee, S. and Harkless, L., 2006, Risk of Reamputation in Diabetic Patients Stratified by Limb and Level of Amputation: 10-year observation, http://care.diabetesjournals.org/content/29/3/566.long, Diabetes Care, March vol. 29 no. 3 566-570
  3. Pecoraro RE, Reiber GE, Burgess EM., 1990, Pathways to diabetic limb amputation. Basis for prevention., Diabetes Care. 1990 May;13(5):513-21.
  4. Peppa, M., Uribarri, J., and Vlassara, H., 2003, Glucose, Advanced Glycation End Products, and Diabetes Complications: What Is New and What Works, Clinical Diabetes, October 2003 vol. 21 no. 4 186-187
  5. Physical Therapist Practice in Geriatrics 2011, Issue 6, Diabetes Across the Physical Therapist Practice Patterns, Scarborough,P. APTA, 2011)