Complications post forefoot amputation: Amputee case study

Title

Complications post forefoot amputation: Amputee case study

Abstract

This case study outlines the journey of a 67-year-old female who initially presented to hospital with gangrene affecting her left toes. This was surgically treated with a forefoot amputation, however a number of complications post operation resulted in a prolonged hospital stay and delays in the rehabilitation process. The majority of these can be related to complications of diabetes. This study looks at the acute pre- and post-amputation period primarily from a physiotherapy perspective.

Key Words

Forefoot amputation, diabetes, complications

Client Characteristics

In May 2015, a 67-year-old Cook Island Maori female (Mrs. A) presented to a New Zealand hospital with gangrene affecting the toes of her left foot. Her co-morbidities included type II diabetes, end stage renal failure and peripheral vascular disease. She has historically had difficult intravenous access.
 Mrs. A lived in a house with her extended family and received publicly funded home help for showering. She required assistance of one from her family to mobilise with a superstroller, but had a limited exercise tolerance of five to ten meters. Mrs. A is retired and rarely leaves her house due to health and mobility issues. In recent months, she had noticed increasing difficulties with balance and mobility, and reported recurrent falls (almost weekly).

Examination Findings

Mrs. A's main concern prior to her operation was the pain in her left foot, particularly on weight bearing. Her primary goal was to reduce the pain in her foot so she could go back home and return to her normal family life. In the context of the ICF (International Classification of Function, Disability and Health) model, the gangrene and reduced vascular supply to her left forefoot (body and functions and structures) led limitations at the impairment level (pain and difficulty weight bearing through left foot). These impairments in turn limited activities such as mobilising to the bathroom and transferring to a chair - she required assistance of two and her superstroller to step transfer, and could not mobilise. Consequently her participation in family life was affected, and she was unable to return home to resume her normal roles due to the above issues. Contextual factors, such as having a family member present daily to advocate and support, also contributes to the above model.
No formal outcome measures were completed at this time due to left forefoot pain, and limited functional performance. Informal functional assessments were noted: Mrs. A required assistance of two with bed mobility and transfers. She was unable to mobilise further than a bed to chair transfer.

Clinical Hypothesis

A left forefoot amputation was carried out a few days later. Immediate post-operative physiotherapy assessment was delayed due to low level of consciousness (measured by Glasgow Coma Scale (GCS)), delirium, acute on chronic kidney failure and difficulties with dialysis access. The surgical team were also concerned with sepsis resulting in multiple scans and investigations during this time. Dialysis access was obtained via a femoral line after four days of attempts, and delirium and low GCS slowly started improving as dialysis was commenced.
In these initial ten days, physiotherapy assessment and input was limited to assessing her respiratory function, as Mrs. A was unable to follow commands and the focus was primarily on acute medical management. As her delirium resolved further physiotherapy assessments were carried out - this included range of movement, power, function, examination of the site of amputation (bed mobility, sitting balance, transfers).

For her first four weeks post-amputation, Mrs. A was non-weight bearing through her left foot as determined by the orthopaedic team. The rationale for this was slow healing of the amputation wound site and increased wound ooze.
After the initial functional physiotherapy assessment,

After Mrs. A's acute post-operative symptoms improved, her main issues were pain and sensitisation at the amputation wound site, delayed wound healing (likely due to poor vascular supply and diabetes) and general deconditioning following bed rest

Intervention

As soon as Mrs. A's level of consciousness and delirium improved to the extent she could follow instructions, deep breathing exercises and active range of movement exercises were commenced during physiotherapy sessions. Mrs. A was able to perform active range of movement of her upper limbs and right lower limb, but required assistance with active movements of her left lower limb.

Once Mrs. A was medically stable, she was taken to the physiotherapy gym and hoisted to a plinth. Interventions included sitting balance (progressed to reaching out of base of support), bed mobility (rolling, moving up and down bed, lie to sit), and transferring with a sliding board (part-task training, full task training). Other interventions included education and desensitisation of the residual left foot.

Outcome

On first physiotherapy assessment, Mrs. A required assistance of one with active leg exercises, sitting balance and rolling, and assistance of two to three to transfer via hoist. Over the three weeks of physiotherapy input on the acute surgical ward, Mrs. A progressed to being independent with her leg exercises, rolling and sitting balance. She could transfer with a sliding board and assistance of two people. 
Five weeks after her amputation, Mrs. A's weight bearing status changed to heel-weight bearing with a rocker bottom shoe. Although this meant Mrs. A could now transfer with a sliding board and only one person assisting, it became apparent that sensitivity and pain of the left residual foot was an issue after more than a month non-weight bearing. The wound was also still slow to heal, which meant desensitisation of the residual left foot and heel weight bearing had to be balanced with the avoidance of excessive pain and shear forces over the wound site. Because of the initial delirium, the pain team were also reluctant to increase Mrs. A's analgesia throughout this time. At this point, Mrs. A was transferred to inpatient rehabilitation with the aim of increasing independence prior to discharge home.

Discussion

The original reason for Mrs. A's amputation was gangrene, which is a defined as an area of necrosis caused by reduced blood supply to the affected tissues[1]. The World Health Organisation (2015) states that diabetes increases the risk of gangrene due to the long-term complication of damage to small blood vessels (often to the eyes, kidneys and nerves)[2]. In Mrs. A's case, the slow wound healing of the amputation site is likely related to her diabetes and resulting peripheral vascular disease. Unfortunately this puts her at higher risk of further amputation of her residual foot - if the wound does not heal due to poor blood supply, an amputation at a higher level may be necessary. This is an important factor to take into consideration during the rehabilitation process as Mrs. A will be unable to progress to prosthesis fitting until there is sufficient healing of the amputation wound. Furthermore, Mrs. A's contralateral leg is also at higher risk of amputation due to the known peripheral vascular disease also affecting it. Physiotherapy sessions included education on preventing damage by reducing abnormal stresses on the contralateral leg. This include transfer training, where Mrs. A was instructed to move slowly during the sliding board transfer and shift her body across in small increments to avoid pivoting or shearing forces to the foot tissue[3], and thereby avoid micro-damage.

References

  1. Porth and Carol (2007). Essentials of pathophysiology. Lippincott Williams & Wilkins. p. 41. ISBN 978-0-7817-7087-3. Retrieved 07 April 2015.
  2. "Diabetes Programme". World Health Organization. Retrieved 07 April 2015.
  3. Veves, Giurini, Logerfo, The Diabetic Foot: Second Edition. ISBN: 978-1-58829-610-8. Retrieved 07 April 2015