An amputation is the loss or removal of a part of your body, such as an arm or leg. The loss of a limb can be a life-changing experience, but there is help and support available.

There are several reasons why someone might need to have an amputation. These can include:

• diabetes complications
• peripheral vascular disease (narrowing of the arteries leading to your legs and feet)
• other causes of severely reduced blood supply to the limb
• severe infection
• cancer
• serious injury

Many people can use a prosthesis (artificial limb) or mobility device to regain function after an amputation.

Introduction

Over 150,000 people undergo amputations of the lower extremity in the United States each year. This incidence is directly proportional to rates of peripheral arterial occlusive disease, neuropathy, and soft tissue sepsis. This correlation is due to the increased incidence of diabetes mellitus, which is present in 82% of all vascular-related lower extremity amputations in the United States. Patients with diabetes mellitus have an astounding 30 times greater lifetime risk of undergoing an amputation when compared to patients without diabetes mellitus, which translates to an economic strain in healthcare systems of over $4.3 billion in annual costs in the USA alone.] Trauma to the lower extremity can lead to amputation in over 20% of patients when associated with severe wound contamination and significant soft tissue loss.] Battle-related explosive events can lead to amputation in 93% of cases and approximately 2% of combat casualties least to limb amputation.

This activity focuses on amputations at the level of the femur and distally. It covers above-knee, through-knee, and below-knee amputation. In addition, it describes the technique for certain foot amputations (Syme, Chopart, Boyd), but the reader is encouraged to seek further in-depth text to review these techniques. Amputations are procedures performed surgically, although on rare occasions and in limited settings, they can be performed employing cryoamputation.

Anatomy and Physiology

The lower extremity is subdivided into the thigh (between the hip and knee joints), lower leg (between knee and ankle), and the foot (calcaneus and distally).

Thigh Compartments

Anterior compartment

• Sartorius
• Quadriceps: composed of rectus femoris, vastus lateralis, vastus medius, and vastus intermedius.
• Superficial femoral artery and vein

Medial compartment

• Adductor magnus muscle
• Gracilis muscle
• Deep femoral artery and vein
• Saphenous nerve: located in the subcutaneous tissue of the medial thigh and runs parallel to the intermuscular septum of the anterior and medial compartments

Posterior compartment

• Biceps femoris muscle
• Semitendinosus muscle
• Semimembranosus muscle
• Sciatic nerve

Lower Leg Compartments

Anterior compartment

• Tibialis anterior muscle
• Extensor hallucis longus muscle
• Extensor digitorum longus muscle
• Peroneus tertius muscle
• Anterior Tibial artery
• Anterior tibial vein
• Deep peroneal nerve

Lateralcompartment

• Peroneus brevis muscle
• Peroneus longus muscle

Deep posterior compartment

• Tibialis posterior muscle
• Flexor digitorum longus muscle
• Flexor hallucis longus muscle
• Posterior tibial artery
• Posterior tibial vein
• Peroneal artery
• Peroneal vein
• Tibial nerve

Superficial posterior compartment

• Soleus muscle
• Gastrocnemius muscle
• Plantaris muscle
• Sural cutaneous nerve: lesser saphenous vein located in the subcutaneous tissue of the posterior lower leg and runs parallel to the sural nerve

Foot Compartments

The foot comprises 7 tarsal bones, 5 metatarsals, and 14 phalanges. It is subdivided into hindfoot (talus and calcaneus bones), midfoot (cuboid, navicular, 3 cuneiform bones), and forefoot (metatarsals and phalanges). The muscles of the foot can be extrinsic, originating from the anterior or posterior aspect of the lower leg, and intrinsic muscles, originating from the foot.

Indications

Indications for amputation are related to the degree of tissue necrosis or viability, and it is performable in either a single operation or a staged manner (amputation followed by reconstruction). The decision to take either approach depends largely on the clinical status of the patient and the quality of the soft tissues at the desired level of amputation, with the primary goal being to excise the non-viable and infected tissue. In general, soft tissue quality and the ability to obtain bone coverage guide the adequacy of the level of amputation. It is important to note that skin grafts are an acceptable option for patients where adequate muscle coverage is obtainable, where skin coverage is not possible.

Patients with diabetes mellitus can present along a spectrum of diseases, from a non-healing foot wound with underlying osteomyelitis to a grossly infected wound leading to septic shock. In peripheral vascular disease, this decision to amputate is made with the appearance of non-healing wounds when there are no options for the restoration of flow. These patients can generally present in 1 of 2 ways: in the acute setting with infected necrosis (wet gangrene) leading to sepsis or with ischemic necrosis (dry gangrene) where the tissue is necrotic without signs of systemic compromise.

Before deciding to amputate, it is essential to optimize the patient from a medical standpoint. In patients with diabetes mellitus, all efforts should focus on achieving adequate glycemic control and early antibiotic treatment to minimize the risk of surgical site infection and maximize the length of non-infected tissue, respectively. It is reasonable to consider these patients candidates for a single operation should the quality of the soft tissue allow it. In the patient presenting with septic shock, the decision to perform an open (guillotine) amputation with staged reconstruction versus a single operation depends on the clinical status of the patient, and the primary goal should be to obtain adequate source control, leaving reconstruction for a later date. Patients presenting with signs of a systemic inflammatory response and extensive cellulitis may receive initial treatment with intravenous antibiotics. A decrease in cellulitis may allow for a more distal level of amputation than anticipated as well as allowing the operation to take place in a single stage.

High-energy traumatic injuries can lead to amputation at the moment of injury. Alternatively, patients can present to the hospital with a mangled extremity not amenable to reconstruction. Several scoring systems can be utilized to determine whether complex reconstruction options should be pursued. However, the primary focus should have its basis in employing the Advanced Trauma Life Support protocol since it is likely that patients present with concomitant life-threatening injuries. This includes assessment of bleeding from the wound, obtaining hemostasis, and performing adequate resuscitation. The level of amputation depends on the viability of the soft tissues used to obtain bone coverage. It is important to note that victims of severe traumatic lower extremity injury who initially were candidates for limb salvage may become candidates for an amputation due to infection, inability to obtain bone or hardware coverage, persistently high pain levels, or lack of the desire to submit to lengthy reconstructive protocols for poor functional results.

Contraindications

Patients with advanced peripheral vascular disease often have diabetes, are elderly, and have multiple comorbidities with low physiologic reserve. It is, therefore, ideal to medically optimize these patients before a definitive operation. However, an emergency lower extremity amputation may be required to allow for clinical improvement, and the risks of surgery anesthesia must be discussed with the patient and/or designated advocates.

Certain patients are in the intensive care setting receiving vasoactive infusions and heavy sedation with low cardiopulmonary reserve. Amputation may be indicated, but their critically ill state does not allow for such. It is acceptable to wait for clinical optimization before performing an amputation. An alternative to this is cryoamputation, the concept of refrigeration of unsalvageable ischemic limb in critically ill patients. There are many described techniques which include the application of ice bags, ice water immersion, mechanical refrigeration, and utilizing dry ice. Although cumbersome, it can be employed successfully with appropriate training of clinicians and the creation of institutional protocols. A subsequent formal amputation procedure can then follow once the metabolic derangements have resolved and the benefits of the surgery have surpassed the risks.

Equipment

The procedure occurs in the operating theater in a sterile environment using an appropriately sized tourniquet. The patient is in the supine position and under general anesthesia or regional blockade. Of note, some patients may have no vascular inflow, and therefore, a tourniquet is not necessary. However, careful consideration should focus on the skin by covering it with a cotton roll or stockinette before application of a tourniquet.

A ruler and marking pen are used to demarcate the skin incision and soft tissue flap. A large 15 or 20-blade can incise the skin and soft tissues. Alternatively, electrocautery is an option for the soft tissues and the entire dissection, with fresh blades reserved for nerve transection. A Gigli saw or a power saw is used for transecting the bones. The power saw can also be utilized to soften the edges of the bone once transected. Alternatively, a bone rasper can be used and allow for more control and possibly smoother curvature of the anterior surface of the bone. A drill, a 2.0 mm drill bit, and fiber wire suture are used if performing a myodesis. The tissue is closed in layers. Dressing materials can include petroleum gauze, soft rolls, army battle dressings, and an elastic bandage for compression.

Personnel

Every team performing a lower extremity amputation must include an operating room nurse, a scrub technologist, a surgical assistant, and an anesthesiologist. Post-anesthetic care unit staff are vital in the patient's care in the immediate postoperative period. Face-to-face communication from the surgery team is obligatory during patient hand-off. This is an opportunity to summarize the patient and the reason for the operation performed. It also allows the surgeon to communicate adversities encountered during the case, report on estimated blood loss and discuss resuscitative measures used intra-operatively that may need continuation in the immediate post-operative setting. It is also important to communicate the type of hospital unit the patient goes to thereafter and the need for post-operative laboratory values.

Preparation

The most important part of the preparation after medical optimization is determining the level of amputation. Transcutaneous oxygen tension (TcPO2) is a measure of oxygen tension in the skin derived from the local capillary blood perfusion. This has been utilized as a tool to determine the level of amputation in ischaemic limbs, which demonstrated that patients with primary healing of postoperative wounds had significantly higher values of TcPO2 than patients with failure to heal (37 mmHg; range 15-56 mmHg vs. 18 mmHg; range 8-36 mmHg, p 0.01). Although useful in the setting of isolated peripheral vascular disease, this tool does not consider the condition of the patient, the condition of the soft tissues, the presence of neuropathy, or the functional status of the patient, all of which are also determinants in selecting amputation level. An accepted approach to amputation level determination in the patient with peripheral vascular disease is the presence of a femoral pulse; this indicates patency of the deep femoral artery, which has general acceptance as appropriate for a transtibial (below-knee) amputation. On the other hand, efforts for revascularization must undergo an assessment before performing an above-knee amputation in the absence of a femoral pulse. Despite many available modalities for assessing healing potential, none has proven more useful than a good physical exam. Pulse, temperature, and hair growth patterns are all useful and guide clinical intuition.

It is imperative to discuss the probability of independence after a major lower extremity amputation with the patient. AMPREDICT is a user-friendly prediction tool for mobility outcomes in individuals undergoing major lower extremity amputation because of complications of diabetes or peripheral vascular disease. Informing the patient of their probability to achieve independence in the 12 months following amputation allows for shared-decision making and, more importantly, allows the patient to understand their mobility prognosis during the strenuous recovery period. Ambulation rates outside the home decrease drastically as the length of amputation decreases. Energy expenditure for ambulation increases significantly as the amputation site moves higher.

More often than not, the level of amputation is determined by the degree of soft tissue compromise/infection despite optimal antibiotic therapy. In patients presenting with gangrene or necrotizing soft tissue infection, there is very little room for discussion, and the primary objective is to preserve life. A secondary objective in this setting is to preserve as much functional limb length as possible, as this has a significant impact on the patient's postoperative functionality.

Technique or Treatment

The use of general anesthesia (GA) versus regional anesthesia (RA) for performing major lower extremity amputation is an area of ongoing debate. There is literature to support the use of RA for major lower extremity amputation with decreased blood loss, need for transfusion, postoperative pain medication, and faster time to oral intake when compared with the general anesthesia group. Another study showed there was no difference in postoperative myocardial infarction or mortality between GA and RA. More recently, the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) was utilized to determine the effect of anesthesia type on major lower extremity amputation outcomes in functionally impaired elderly patients. They reviewed over 3000 patients over 8 years. Fifty-nine percent underwent above-the-knee amputations, and the remainder were below-the-knee. Patients undergoing GA were more apt to have impaired sensorium, be on anticoagulation, or have a bleeding disorder and had a prior operation within 30 days. GA correlated with shorter anesthesia time to surgery but equivalent operative times to RA. There was no difference with regard to postoperative myocardial infarction/cardiac arrest, pulmonary complications, stroke, urinary tract infections, and wound complications. Therefore, deciding which anesthesia type to use should be performed on a case-by-case basis and collectively between the patient, surgeon, and anesthesiologist.

There are several components in the preparation of the patient in the operating room which apply to all amputation levels. The patient should be in the supine position with the appropriate use of a tourniquet, as this has been shown to reduce blood loss during lower extremity amputation in the setting of peripheral artery disease. Skin preparation should be performed circumferentially and proximal to the groin. Skin preparation products contain iodophors or chlorhexidine gluconate, both acceptable options. In diabetic foot wounds or gangrene, we recommend maintaining the wound with a dry dressing and covering the affected foot with a sterile impermeable stockinette. An occlusive adhesive dressing can create a seal and further isolate this from the incision site.

Principles of amputation surgery at any level include removal of diseased tissue, providing a residual limb that allows for prosthetic fit, tapering the ends of the bone to avoid sharp edges, providing a conical-shaped limb to allow better prosthetic fit, controlling postsurgical edema, avoiding hematoma formation, allowing for nerve retraction, preservation of length and optimized postoperative pain control. The critical steps in surgical technique for several amputation levels in order of proximal to distal include:

Above-Knee Amputation

1. The anterior and posterior flaps should be marked before incision to resemble an ellipse or fishmouth. It is useful to measure the circumference and mark the apices equally. If length is not an issue, the tip of the anterior flap should reach the edge of the patella with a mirror image posterior flap.
2. Tourniquet and Esmark bandage is used. An incision is carried through the fascia, and the anterior musculatures are divided with cautery.
3. The muscle gets divided to the femur level, and the periosteum is elevated from the femur circumferentially to the level of the incision apex.
4. An oscillating saw or Gigli saw is used to divide the femur. The adductor tendon is separated separately from the medial epicondyle and distal femur; this may be preserved for use in a myodesis. The edges are then rasped smooth.
5. The femoral artery and femoral vein are clamped and suture ligated with heavy suture.
6. The saphenous nerve should be dissected proximally and divided on tension. It is this author's opinion that avoiding ligation helps avoid foreign body reactions and future neuroma formation. The nerve should retract 5 cm to 10 cm.
7. If performing a myodesis (preferred by this author), a 2 mm drill bit is used to make a medial and lateral osteotomy on the distal femur.
8. The preserved adductor tendon is then secured to the osteotomies medially and laterally with heavy non-absorbable fiber-wire or braided nylon suture.
9. If the medullary canal remains open, the elevated periosteum can be reapproximated with a heavy absorbable suture.
10. The posterior tissue then gets divided with an amputation knife or cautery.
11. The sciatic/tibial nerve is now divided and allowed to retract as above
12. The tourniquet is released, and all bleeding is ligated.
13. A subfascial drain is left in place if needed but is generally unnecessary.
14. The anterior and posterior flap is reapproximated with a heavy absorbable suture at the fascia.
15. Skin and subcutaneous tissues are closed in layers.

Through-Knee Amputation

1. An elliptical incision similar to the above knee is made with the apices at the medial and lateral epicondyles near the top of the patella if a line were extended around the femur. The anterior flap distal margin extends to the tibial tuberosity. The posterior flap should attempt to mirror the anterior flap.
2. A tourniquet is used as above. The surgeon employs a similar technique through the fascia as above.
3. The patellar tendon detaches from the tibia, and the surgeon enters the knee joint.
4. The joint capsule is incised circumferentially, and the cruciate ligaments are divided from within the knee joint.
5. Before dividing the posterior joint capsule and posterior tissues, it is useful to identify the semitendinosus medially and the biceps femoris laterally as they insert into the tibia posteriorly. They should be held with a Kocher clamp to prevent retraction.
6. Popliteal artery and vein individually suture ligated.
7. The common peroneal and tibial nerves are divided under tension and transected sharply to allow retraction.
8. The posterior tissues get divided with an amputation knife or cautery. It is not necessary to preserve any gastrocnemius muscle.
9. The specimen is removed at this point.
10. An oscillating saw is used to make 6 osteotomies removing all of the articular surfaces while preserving most of the adductor insertion medially; this is cancellous bone with no medullary canal.
11. The patella is then everted and removed from the inner surface of the patellar tendon, taking care not to injure the thin skin from the bare area in the mid-tendon.
12. The tourniquet is released, and further hemostasis is achieved with ligatures.
13. Myodesis then follows by suturing the semitendinosus and biceps to the cruciate remnant posteriorly and the patellar tendon to the cruciate anteriorly. This process is performed with heavy fiber wire or braided nylon.
14. Fascia, subcutaneous tissue, and the skin closed as above.

Open Below-Knee Amputation

1. This procedure is performed as distal as the soft tissues allow and can take place expeditiously with a Gigli saw through all structures followed by suture ligation of vascular structures. The residual limb is covered with wet-to-dry dressings once hemostasis is obtained.
2. The alternative is to use a scalpel and electrocautery for the skin, subcutaneous tissue, and muscle, followed by isolation and control of vascular bundles. A power saw, or the same Gigli saw, can be used for bone. The residual limb is covered with wet-to-dry dressings upon achieving hemostasis.

Formal Below-Knee Amputation

1. The level selected depends largely on soft tissue viability, with the ideal length being approximately 12 to 18 cm from the tibial tubercle.
2. It is useful to have a standard technique to determine skin flaps. This author prefers to measure the diameter at the transection site and make the anterior flap one-half the circumference and the posterior long flap's full circumference; this prevents unnecessary tension at the time of closure. Additionally, longer residual limb lengths typically involve a smaller circumference and thereby have less chance for tension.
3. The incisions are carried through the skin, subcutaneous tissue, and anterior muscle with suture ligation of vasculature identified.
4. The tibial bone gets transected with a power saw or Gigli saw, and the tibial edges are blunted with a rasper. The power saw, or rasper can be used to bevel the anterior aspect of the tibia. This process reduces trauma to the posterior flap as it sits along a smooth surface.
5. The fibula gets transected in the same manner at approximately 1 cm proximal to the tibial transection, and sharp edges are removed with rasper, giving the residual limb a cornified aspect.
6. The posterior tissue is divided with an amputation knife, leaving only a thin portion of the soleus but preserving the gastrocnemius.
7. At this point, ligation of the anterior tibial, posterior tibial, and peroneal arteries is confirmed before the tourniquet is released. The tibial, deep and superficial peroneal, and soleus nerves divide on tension.
8. The myodesis is performed by bringing the Achilles tendon to the tibia. Three osteotomies are created with a 2 mm drill bit in the anterior portion of the tibia. Fiber-wire or heavy braided nylon is used to secure the Achilles to the tibia utilizing the 3 osteotomies in a mattress fashion.
9. Skin and subcutaneous tissues are closed in layers.

ERTL Amputation

1. All steps are similar to formal below-knee amputation, except a keyhole incision is used, extending just lateral to the tibial distally and then around the ankle. The tibialis anterior muscle is preserved in the anterior compartment.
2. An osteal periosteal graft is raised using a hammer and chisel and left attached to the tibia anteriorly.
3. The fibula is transected at the same length as the tibia.
4. The soleus muscle and anterolateral compartment muscle are transected. A GIA stapler is useful for this.
5. Vascular bundles and nerves receive similar treatment.
6. A portion of the fibula is trimmed to create a strut between the tibia and fibula, which gets secured with a tightrope device, plate, or headless screw.
7. The periosteal graft is secure around the fibula strut to aid in ossification
8. The tibialis anterior is secured over the strut, followed by the Achilles myodesis (pants over vest).
9. The closure begins anteriorly, and the skin and subcutaneous tissue are resected as the closure proceeds posteriorly

Syme Amputation

1. A weight-bearing amputation through the ankle that involves removal of all of the bones of the foot while preserving the heel pad for weight-bearing

Boyd Amputation

1. A weight-bearing amputation through the ankle preserves the calcaneus and heel pad for weight-bearing.
2. The calcaneus gets fused to the tibia and is non-mobile

Chopart Amputation

1. A weight-bearing amputation at the midtarsal level preserves the additional length of the foot

Complications

Lower extremity amputations involve significant perioperative morbidity and mortality. Thirty-day postoperative mortality rates can range from 4% to 22%. Long-term mortality rates at 1, 3, and 5 years can reach 15, 38, and 68%, respectively. Mortality rates in diabetic lower extremity amputation patients can be as high as 77% at 5 years. Risk factors for death in the perioperative setting include AKA, postoperative cardiac complications, age over 74 years, and acute renal failure. A review of 2879 amputees demonstrated the most common post-surgical complications included pneumonia (22%), acute kidney injury (15%), deep venous thrombosis (15%), acute lung injury/acute respiratory distress syndrome (13%), osteomyelitis (3%) and flap failure (6%).

Wound complications, which include dehiscence, seroma, and hematoma, can occur in 12% to 34% of BKA patients and 6% to 16% of AKA patients. Risk factors for wound complications include sepsis, compartment syndrome, end-stage renal disease, ongoing tobacco use, body mass index over 30 kg/m2, and BKA.] A retrospective study showed that the use of incisional negative pressure wound therapy (NPWT) in major limb amputation and revision amputation had demonstrable benefits in decreasing the risk of wound complications.

Phantom limb pain (PLP) is the pain that persists after complete tissue healing and is characterized by dysesthesia at the level of the absent limb. Patients describe this pain as burning, throbbing, stabbing, and sharp, as well as the sensation that the amputated limb is in an abnormal position. This pain can be present in 67% of patients at 6 months and 50% of patients at 5 to 7 years. There are several risk factors for developing PLP, which include: the presence of pre-amputation pain, female gender, upper extremity amputations, and bilateral amputations of the upper and/or lower extremities. A multidisciplinary approach, which includes surgical technique, regional analgesia, pharmacological agents, physical therapy, and psychotherapy, are all key components in the peri-operative care of an amputee that can have a strong impact on decreasing the risk of PLP.

Revision amputation procedures can occur in as many as 42% of patients who underwent a below-knee amputation secondary to trauma. Additionally, up to 13% of patients undergo revision to a higher level of amputation. Age, presence of a crush injury, compartment syndrome, and experiencing a major post-surgical complication were significant risk factors of revision amputation.

It is also important to include psychological trauma as a complication of limb loss. A recent review performed by Mckechnie et al. reveals that depression can occur in 20.6 to 63% of patients (3 times higher than the general population) and anxiety in 25% to 57% (approximately the same as the general population) with 83% of patients attending a psychiatric clinic at 1 point after their surgery.. Darnall et al. demonstrated an increased risk of depressive symptoms in patients undergoing an amputation secondary to trauma versus vascular disease or cancer. Current research, such as "Amputees Unanimous: A 12-step Program", focuses on a multimodal approach toward the care of an amputee, which aims to provide encouragement, support, and optimism for the future. Further research is needed to determine their impact on this patient population.

Clinical Significance

An amputation not only reduces mobility but can cause significant impairment in quality of life. There is increased energy expenditure with higher levels of amputation. The mean oxygen consumption in unilateral below-knee amputees compared to unimpaired subjects has been shown to increase by 9%. This increase is even more notable in above-knee amputees at approximately 49% and 280% in those with bilateral above-knee amputees. The rate of metabolic expenditure is higher in dysvascular amputees compared to traumatic amputees. The extent of the disease dictates the level of the amputation. Through-knee amputation is a reasonable alternative to above-knee amputation should perfusion and soft tissue conditions allow. TKA has demonstrated similar morbidity and mortality compared to AKA and can provide a better end-weight-bearing residual limb, improved stability with adductor preservation, and improved prosthetic comfort. An above-knee prosthetic can sit on the ischium and can require removal for activities of daily life, such as sitting on the toilet. The through-knee amputation is generally preferable in younger patients or any patients with ambulatory potential, with the above-knee amputations preserved for those non-ambulatory bed-bound patients or those with advanced vascular disease.

Technological advancements in materials and ways to optimize the coupling between the residual limb and socket drive prosthetic development. Gel liners protect the skin while allowing for the suction suspension of the prosthetic. An active suction device can also be implemented as a mechanical pump that activates during ambulation. Improper fit leading to discomfort is the most common reason for rejection of prosthetic devices. However, patients may also be very self-conscious of the appearance of their residual limb, which may disincentivize its use. Therefore, a silicone cover or sleeve that mirrors the contralateral limb (including tattoos and hair) can be applied. A prosthetist must be involved early in the post-operative care to assist with stump sock fitting and evaluation for an eventual prosthetic limb that adjusts to the patient's needs.

Enhancing Healthcare Team Outcomes

An interprofessional approach is necessary for the care of an amputee. Performing an amputation is a stressful period for most patients. If the procedure is elective, a mental health clinician should consult with the patient. Also, a prosthetic professional should consult with the patient to explain the different prosthetics and when the patient gets fitted with the appliance. After surgery, a wound care clinician must follow the patient to ensure complete healing before fitting any prosthetic device. Pharmacists support glycemic control in patients with diabetes, pain control, and overall medication reconciliation, reporting any issues to the rest of the interprofessional team.

Providers caring for this patient population should include an interprofessional team working closely to provide the best outcome. Every clinician is responsible for ensuring that the patient still can function in society. The social worker must ensure that the home is suitable and that the patient has adequate resources and support services.

The care of an amputee should be individualized based on the patient's overall health status. Clear communication with the patient and their families regarding their treatment course and expectations must be established in the pre-operative setting to facilitate post-operative care and improve the patient-physician relationship. Only through a thorough interprofessional team effort, extending across many months, can patients receiving a lower extremity amputation achieve optimal results and maintain an adequate quality of life.

Nursing, Allied Health, and Interprofessional Team Interventions

The care of an amputee begins and ends with the healthcare team's actions and interventions. Diabetic or peripheral vascular disease patients with foot or leg wounds can often undergo wound care with the assistance of a home healthcare team. Should there be a lack of progression in wound healing or early signs of infection, they are the first to refer the patient to a medical provider and, in some instances, the emergency department. After that, an ER or hospital clinician is generally the first to greet a patient and obtain vital signs, which can indicate the severity of the disease and, therefore, dictate the hospital setting where this patient receives their care. With the assistance of a clinician, the wound is exposed, and the patient is assessed from head-to-toe looking for pressure ulcers, ecchymosis, or hematomas in patients who are wheelchair or bed-bound. Other actions include obtaining adequate intravenous access, medication dispensing and administration, serial symptom assessment including pain, monitoring vital signs, providing wound care and patient hygiene, and liaising between patients, their families, and medical providers.

Nursing, Allied Health, and Interprofessional Team Monitoring

The care of an amputee involves an interprofessional approach. Monitoring in the post-operative setting includes obtaining and recording vital signs, pain scores, and laboratory values. Serial wound assessments allow for early detection of postoperative bleeding and allow the clinician to perform temporizing maneuvers (digital pressure, dressing reinforcement). Pain scores are diligently obtained to titrate the patients' pain medication accordingly and provide the best condition for early mobilization. Close communication between the interprofessional team is necessary to provide patients individualized care based on their needs.

Amputations can be done as emergency or elective (planned) surgery. Finding out that you are facing an amputation can be difficult and scary.

Before planned amputations, you will meet with your surgeon. They will discuss the operation with you and any preparation needed. It can help to take a relative or friend with you to these appointments.

It can also help to make a list of questions before your appointment. This is so that you can discuss these with your doctor or other healthcare providers.

Preparation for an amputation may include:

• a thorough medical examination
• a psychological assessment
• making adaptations to your home or work environment

Your surgeon will remove your limb, or part of the limb under anaesthetic. An anaesthetist (specialist doctor) will discuss with you beforehand what type of anaesthetic will be best for you.

The wound will be closed with stitches or staples. A drain may be inserted under your skin to drain away excess fluid. Your wound will be covered with a wound dressing and bandage.

Pain control

Your wound will be sore after surgery, but this should start to ease in 2 to 5 days. Pain relievers can be used to keep you comfortable after your surgery.

You may feel what is known as 'phantom limb' pain. This means you feel pain in the amputated limb, even though it is no longer there.

Some people also have ‘phantom sensations’, meaning they can still feel the limb that has been removed. You may have sensations such as:

• pins and needles
• itching
• tingling sensations

Phantom limb pain and sensations are common and may last for a few weeks after your amputation. If phantom limb pain persists or is very uncomfortable, speak with your doctor.

Rehabilitation will help you recover and regain your independence.

Usually, several healthcare members will be involved in your care, including a:

• rehabilitation doctor
• nursing team
• occupational therapist
• physiotherapist
• prosthetist (healthcare worker who looks after the design and fit of a prosthesis)
• social worker

Your physiotherapist and occupational therapist will work out a rehabilitation program to help you return to work and other activities.

The program will start a few days after surgery. It will help you manage independently, for example by teaching you how to get in and out of a wheelchair.

You may then progress to an exercise program and learn how to use your prosthetic limb if you have one.

Your physiotherapist will also work with you to keep your joints as mobile as possible. This is to help prevent contractures, where your muscles, skin, tendons or ligaments become shortened and stiff. Contractures can limit how you move. The more you move and exercise, the less likely you will be to develop a contracture.

Prosthesis

You may be able to have a prosthetic (false) limb fitted after your surgery. Your prosthetist and healthcare team will help you prepare for this.

Psychological support

For some people, losing a limb is like losing a loved one and they will need to grieve. Coming to terms with the psychological impact of an amputation is just as important as coping with the physical changes.

Peer support can be helpful — peer support volunteers are people who have experienced and lived with limb loss.

It can also help to join a support group, either in-person or online. Try talking to friends and family about how you are feeling and stay connected.

You may also benefit from professional support, such as seeing a psychologist or counsellor. Talk to you doctor if you have ongoing feelings of:

• anger
• irritability
• denial or grief
• anxiety or depression

Amputation can affect every area of your life, including your home and work. It’s a lot to adapt to, and you will need support.

You may need modifications to your home, or equipment such as:

• a stair-ramp
• handrails
• a wheelchair lift
• a modified car

You may need to change your routines and find new ways to do the things you are used to doing. The right help, training and equipment will make it easier for you to adapt.

Mobility Research

Disturbance Response in Amputee Gait

Eversion and inversion movement model.

Errors in foot placement while avoiding obstacles and maneuvering in the household and community environments may lead to falls and injuries. This research aims to develop an ankle that can invert and evert and thereby control the center of pressure under the prosthetic foot; enhancing balance and stability of lower limb amputees.

Foot-Ankle Stiffness

Models of foot stiffness

Many ambulatory lower limb amputees exhibit fatigue, asymmetrical gait, and the inability to walk at varying speeds. We are using a rapid prototyping approach to fabricate feet of varying stiffness for exploring the effects of foot stiffness on amputee gait.

Turning Gait

Maneuvering required in a typical house.

Turning corners and maneuvering around obstacles are essential abilities for successful community and household ambulation. The aim of this research is to test the efficacy of a compliant torque adapter in the pylons of transtibial amputees.

Energy Storage & Release

Many ambulatory lower limb amputees exhibit fatigue, asymmetrical gait, and the inability to walk at varying speeds. We are developing and testing several approaches aimed at providing the propulsive forces necessary to alleviate these problems.

Three different propulsion test devices.

Stochastic Resonance

Transtibial amputee wearing a stochastic resonance capable socket.

Stochastic resonance (sub-threshold vibration) may enhance peripheral sensation sufficiently to result in improved postural stability and locomotor function. This research explores application of this phenomenon to the residual limb and intact plantar surface of diabetic lower limb amputees.

Research in Robotics and Biomechanics

Biologically Informed Robotics

Dr. Aubin’s research spans robotics and biomechanics with applications in health and mobility. He motivates his research by engaging with patients and stakeholders to understand shortcomings in the areas of rehabilitation, prosthetics, orthotics, and physical therapy. Dr. Aubin strives to address these unmet patient and caregiver needs by establishing multidisciplinary research teams that leverage state of the art technologies in robotics, neuroscience, and computational intelligence. Dr. Aubin’s research goal is to develop and utilizes novel sensors, algorithms, assistive powered devices, and robotic tools that can augment human performance and/or improve mobility and function for those affected by disease, age or trauma.

Smart Cane System

Smart Cane System

People with pain or arthritis in their knee often walk with a cane to reduce knee pain and to improve or maintain their mobility. Increased pressure on the knee joint likely causes knee arthritis and reducing the pressure on the knee joint may slow the progression of arthritis. Walking with a cane reduces the pressure inside the knee joint, but only if the cane supports 10% to 20% of a person’s weight. Many people may not be using their cane in the best way they can because they don’t know how much force (percent of their body weight) they are putting on the cane when they walk. In this study we are looking at how using a computerized cane that beeps or vibrates (like a cell phone) when a certain amount of force is applied to it might help people learn to more effectively use a cane. We are also examining how walking with a cane changes the pressure in the knee joint. We hypothesize that giving the user biofeedback, a sound or vibration signal from the cane, will help them apply the optimal amount of force on the cane. Our secondary hypothesis is that increased cane loading will result in a decrease in knee joint pressure.

Sensory Feedback For Prosthetic Limbs

It has long been recognized that restoring movement function after amputation is a priority. We are now entering an era in which restoration of sensation may be possible as well through the use of smart sensorized prosthetic devices and haptic feedback. We are working on understanding how feedback of forces and events on the foot - for example the placement of the prosthetic foot as the user is walking down stairs - can lead to improved function.

Injury Prevention Research

Vacuum Suspension Systems

Many amputees live with an ill-fitting socket and can experience limb pistoning within the socket, which in turn may result in skin irritation, tissue breakdown, discomfort, and a reduction in activity. The aims of this research are to characterize the response of the lower residual limb to a vacuum suspension system and to measure changes in limb volume with a structured light scanning system.

Vacuum suspension system modelling

Socket Systems & Tissue O₂

Fiber-optic video-oximetry imaging system

Limb health and wound healing capacity is closely related to the amount of oxygen present in limb tissues. Using our fiber-optic video-oximetry imaging system, we aim to discover if prosthetic prescription can influence residual limb tissue oxygenation during both rest and gait.

Distributed Sensing

The goal of the proposed project is to develop enabling sensing technology based on a flexible array and to build a prototype of a prosthetic liner with distributed, unimodal field sensing capability. The specific aims include: (1) the design of the flexible sensing array for measurement of moisture, temperature, pressure, and shear stress; (2) integration of this array into a prosthetic liner/socket; and (3) testing of device performance.

Distributed sensing images

Torsional Prosthesis

This research seeks to develop a prosthetic limb whose torsional characteristics can adapted depending activity. Our goal is to reduce torsional stresses and the incidence of residual limb injuries.

This research seeks to develop a prosthetic limb whose torsional characteristics can adapted depending activity. Our goal is to reduce torsional stresses and the incidence of residual limb injuries.

Patient Comfort Research

Thermal Comfort

Lower limb amputations often experience discomfort related in part to higher skin temperatures within their prosthetic socket. Our research has found prosthetic liners and sockets are excellent insulators that can retain heat. Activity can cause a dramatic increase in skin temperature within the prosthesis requiring substantially long periods of inactivity to restore resting state temperatures. Our current work involves developing active cooling systems and embedded sensor networks to monitor skin temperature.

Lower limb amputations often experience discomfort related in part to higher skin temperatures within their prosthetic socket. Our research has found prosthetic liners and sockets are excellent insulators that can retain heat. Activity can cause a dramatic increase in skin temperature within the prosthesis requiring substantially long periods of inactivity to restore resting state temperatures. Our current work involves developing active cooling systems and embedded sensor networks to monitor skin temperature.

Evaporative Cooling and Perspiration Removal

Amputees often complain about uncomfortably warm residual limb skin temperatures and the accumulation of perspiration within their prosthesis. This research will discover if a novel evaporative cooling system can provide ameliorate these problems.

Sometimes, when a limb is removed during an amputation, an individual will continue to have an internal sense of the lost limb. This phenomenon is known as phantom limb and accounts describing it date back to the 1800s. Similarly, many amputees are frequently aware of severe pain in the absent limb. Their pain is real and is often accompanied by other health problems, such as depression, anxiety, sleep disorders and a general decrease in quality of life.

What causes this phenomenon? Scientists believe that following amputation, nerve cells "rewire" themselves and continue to receive messages, resulting in a remapping of the brain's circuitry. The brain's ability to restructure itself, to change and adapt following injury, is called plasticity (see section on Plasticity).

Our understanding of phantom pain has improved tremendously in recent years. Investigators previously believed that brain cells affected by amputation simply died off. They attributed sensations of pain at the site of the amputation to irritation of nerves located near the limb stump. Now, using imaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI), scientists can actually visualize increased activity in the brain's cortex when an individual feels phantom pain. When study participants move the stump of an amputated limb, neurons in the brain remain dynamic and excitable. Surprisingly, the brain's cells can be stimulated by other body parts, often those located closest to the missing limb.

Treatments for phantom pain may include analgesics, anticonvulsants, and other types of drugs; nerve blocks; electrical stimulation; psychological counseling, biofeedback, hypnosis, and acupuncture; and, in rare instances, surgery.