VIDEO: Two amputations a week are carried out on diabetes patients in Leicestershire | ITV News * 2023
VIDEO: Two amputations a week are carried out on diabetes patients in Leicestershire | ITV News * 2023

Current problem when presenting more cases of diabetes mellitus

The incidence of diabetes mellitus (DM), especially type 2, is increasing in the developed world. The estimation of the increase in its prevalence and the very high costs generated are or should be a matter of great concern for professionals and health institutions.

Along with the eye and the kidney, the foot is one of the most common locations for chronic diabetes-induced complications. In the case of the feet, this complication has been neglected and continues to be so in many areas.

It is estimated that Diabetes Mellitus entails a 15-20 times higher risk of suffering a major amputation of the lower extremity (supra- or infracondylar) and between 5% and 15% of diabetics will suffer an amputation throughout their lives.

The objective is to emphasize the importance of recognizing the risk factors for amputation, its consequences and, finally, try to provide the data extracted from current knowledge to minimize the impact of amputation in the diabetic patient.

Main member affected the foot

The severity of the complications of diabetes in the foot is not necessarily related to the severity of the disease and, furthermore. Most complications occur in patients with moderate forms of the disease, often with type 2 DM, which puts a huge number of patients at risk.

Diabetes-related lower extremity conditions that increase the risk of amputation include peripheral neuropathy, peripheral vascular disease, and infection.

A major amputation means a reduction in the life expectancy of the diabetic patient, and in some cases only half of the patients will be able to walk again later (with or without prosthesis). On the contrary, a distal amputation (transmetatarsal or midtarsal) allows the ability to walk to be preserved in up to 92% of cured cases. For this reason, many of the current efforts are aimed at finding treatment strategies to convert what in the past ended up being an infracondylar amputation into a partial amputation of the distal foot at the transmetatarsal level. A location that preserves a more favorable biomechanics for the patient.

Vasculopathy, in its macro- or microangiopathic form, is decisive in the prognosis of the limb. However, the role of peripheral neuropathy, in the form of neuroarthropathy, is a triggering factor for deformities and thus ulcerations and infections in the diabetic foot.

Most frequent types of amputations

Despite the many options available, it should be noted that virtually any amputation drastically alters gait. For example, it is known that a simple loss of the metatarsophalangeals (MTF) produces a great negative effect.

Big toe amputations:

It can be done through an MTF disarticulation although, whenever possible and although technically it is a bit more demanding, we believe that it is preferable to preserve the base of the proximal phalanx. The potential advantage of its preservation is to partially maintain the biomechanical and functional mechanisms of the first ray through the insertion of the plantar fascia and the flexor hallucis brevis.

Although it is a well-tolerated amputation, it must be said that the alteration of the propulsive phase of gait is important and there are studies that highlight how the amputation of the big toe contributes to generating secondary deformities of the neighboring toes and with it new ulcers.

Lesser fingers amputation:

In the same way as in the hallux, it is preferable, when possible, to keep a remnant of the finger on the disarticulation. In this case, the advantage is that the remaining finger acts as a separator, preventing the deviation of the neighboring fingers.

First ray amputation:

Conceptually it is the amputation of the big toe along with part of the first metatarsal. It is a type of amputation that is easy to fit and fit, although it is not exempt from problems derived from the lack of function of the first ray and the load transfers that derive from it. The tendency to recurrence of ulcers is therefore high and therefore close control and orthopedic treatment should be carried out.

Transmetatarsal amputation:

It is a technically simple amputation that, as its name indicates, is performed through the metatarsal blade, trying to maintain a parabola. It is a very functional amputation, since it keeps intact the Achilles tendon, the anterior tibial (TA) and the posterior (TP), and the peroneal tendons, mainly the peroneus brevis (PB).

Therefore, active dorsiflexion and balance between flexors and extensors, inverters and evertors are maintained. However, and despite the potential biomechanical benefits compared to other distal levels, it has been observed that transmetatarsal amputations cannot generate normal ankle flexor force moments, therefore an unusual activation of the hip flexors is required to replace this. Deficit, pulling the limb forward.

If a shortened Achilles is observed, its elongation is essential to obtain good results and avoid new ulcerations. Transmetatarsal amputations have a cure rate that varies between 72% and 43% depending on the series. Transmetatarsal amputation. Note the large preserved plantar surface that allows a good distribution of loads. Preservation of tendon balance allows for a stable and functional residual limb.

Lisfranc (tarsometatarsal) amputation:

From this distal to posterior level, a loss of the lever arm of the forefoot has been verified in a generic way, as well as a substantial reduction of the plantar load surface (greater pressure per surface), a loss of pronation and supination, and the absence of effective propulsive period (push-off).

This level of amputation supposes the disinsertion of the TA and the PB, so to obtain good results it is essential to rebalance the muscular forces by reimplanting these tendons. In the same way, the lengthening of the Achilles is mandatory (especially in diabetics). If this balance is not achieved, there is a risk of new post-amputation ulcers. Lisfranc amputation, a residual equinus after a Lisfranc amputation can lead to new ulcers.

Chopart (transtarsal) amputation:

It is the most direct competition of the Syme amputation. This amputation is performed through the naviculocuneiform and cuboideometarsal joints.
In its favor, it has technical facility and does not cause shortening of the limb. Faced with more proximal amputations such as the infracondylar, one more advantage is added, which is preserving the natural plantar pad of the heel.

However, this level leaves few functional fitting options. Orthoses are basically aesthetic and have accommodative padding, but they do not provide the limb with efficient biomechanical effects for walking.

Chopart amputation usually evolves towards equinus that can generate new problems and difficulty fitting. In addition, the imbalance generated between flexor and extensor forces facilitates the subsequent deformity of the residual limb, increasing the risk of new ulcers.

Syme’s amputation:

It is a disarticulation of the ankle. One of its initial advantages was a lower mortality rate than infracondylar amputation. This advantage is no longer contemplated because the possibilities of fitting in infracondylar amputations have greatly improved.

Currently, its fundamental advantage is that of sharing the distribution of loads between the distal part of the amputation and the anterior face of the tibia by means of prostheses specially designed for this purpose. However, these prostheses are not capable today of generating such an advanced biomechanical effect as infracondylar prostheses.

A potential disadvantage of this amputation in the diabetic group is that it is subject to new pressure ulcers from the fibular remnant and, in the case of poor perfusion due to vasculopathy, there is an increased risk of secondary cutaneous complications.

Despite many detractors, this level of amputation continues to have support in the medical literature. Thus, in 2003, Pinzur et al. published an article reporting the results in 97 patients with Syme amputations with 85% wound healing. The article concludes that, compared with historical controls for infracondylar amputations, patients with a Syme appear to be able to walk better and live longer.

The ulcers generated in some cases

Diabetic foot ulcers precede amputations by 70%-80%. Ulcers with an ischemic origin are usually preceded by small traumas (sometimes unnoticed). However, neuropathic ulcers are associated with sustained hyperpressure, which is why they are accompanied by hyperkeratosis and generally an erythematous halo. Infection is always an added aggravating problem.

It is vitally important to heal these ulcers, either through conservative measures such as total contact casts or with surgery. Sometimes small surgical steps that carry minimal risk, such as a metatarsal head resection, can heal a years-old ulcer in days and greatly improve the patient’s quality of life.

The physician or surgeon should always keep in mind that a diabetic plantar ulcer is the result of a sensory disturbance together with an underlying bony prominence that produces pressure. Since neuropathy can hardly be modified today, treatment should be aimed at reducing local pressure.

The apparent simplicity of this basic concept must be qualified with variables such as the magnitude of the forces exerted, the number of repetitions of the forces, etc. In this sense, recent studies have provided fascinating information on muscle dysfunction in diabetic patients and its influence on the gait pattern and pressure distribution. Thus, for example, a delay in the activation of the tibialis anterior has been shown, which reduces control of foot contact.

To all this must be added disorders in proprioception and vision. As Bloom stated, “the elderly diabetic patient is often divorced from his feet; poor vision prevents you from seeing them and loss of sensation prevents you from feeling them.”
If ulcers are a major risk factor for ending in amputation, perhaps prophylactic surgery to limit the risk of ulceration could play a role.

However, this must be a carefully considered decision agreed upon by a multidisciplinary team, since it is known that, in the case of sensorimotor neuropathy of the lower extremity, orthopedic surgery entails a great risk, and surgical trauma can even induce a worsening of the Charcot’s disease.

When is it appropriate to amputate and in what way?

Pinzur et al. published an article suggesting 4 phases to guide the decision of what level to amputate:

• First: Will limb preservation be superior in outcome to amputation or a prosthetic limb?
• Second: What is the reasonably expected outcome for a limb-sparing strategy or for an amputation?
• Third: What are the costs of limb preservation, not only in financial terms, but also in terms of suffering and consumption of the patient’s time?
• Fourth: What are the risks associated with the chosen treatment?

Other criteria that can help decide when to stop attempts at limb preservation are the presence of an uncontrollable infection that threatens the patient’s life, the existence of a non-reconstructible deformity, or in cases where sufficient circulation cannot be restored.

Some evidence suggests that the sedentary patient will do better with limb-sparing strategies and/or low levels of amputation. However, more active patients might have a better functional outcome with earlier major amputations.

Choose the level of amputation

There is not only imprecision about when to amputate, but also about where to amputate. Multiple clinical criteria have been suggested to decide the level of amputation. Criteria based on the rehabilitation potential of the patient and other criteria based on the biological potential of the limb to be amputated have been proposed. This last criterion is based on data such as perfusion or vascular status, immune status or the presence of infection and its extent.

The biological level is referred to as the most distal functional level, compatible with a reasonable healing potential of the stump. Limb revascularization may allow the level of amputation to be lower.

Various predictors of the need for a major amputation have been described. In a recent meta-analysis of 101 publications, the most important predictive factors were 4: hypertension, ischemic heart disease, cerebrovascular disease, and peripheral vascular disease. The presence of consistently high glycosylated hemoglobin (HbA1c) values ​​has also been found to be a risk factor for amputation.

Conclusions

Amputations affect not only the quality of life, but also the prognosis of life.
It would be reasonable to continue therapeutic efforts to preserve maximum limb length as long as the patient is in a position to be subsequently rehabilitated to ambulate using the preserved limb.

Current evidence suggests that this could minimize its impact. The distal amputation that seems to best preserve biomechanics and present the lowest risk of reamputations and reulcerations is the transmetatarsal amputation. Infracondylar amputation in active patients presents good prosthetic alternatives.

There continues to be uncertainty about when and where to amputate; therefore, it is essential to find the ideal biological level. The biological level can be improved by prior revascularization.

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