Background
Each year, thousands of people worldwide need to have their lower leg surgically removed (lower limb amputation) due to problems such as blockages in blood vessels (vascular disease), diabetes, and injury. When an amputation is planned, a surgeon needs to decide how high up the leg to go, and therefore how much leg to leave behind. This decision is based on a balance between leaving as much of the leg as possible to improve a person’s ability to walk with an artificial leg (prosthesis) and removing anything that will not survive or go on to heal. If possible, a surgeon will prefer to preserve the knee, as having a working knee of one's own ensures a person’s best chance of walking. In some cases, this is not possible, and currently almost all people in this situation will have an amputation in the middle of the thigh (above the knee). However, another option is an amputation that can be performed through the knee joint itself. This carries potential advantages, as all of the muscles controlling movements of the thighbone are undamaged. A longer remaining leg would be expected to act as a lever to reduce the effort of swinging a prosthetic limb during walking and to aid sitting balance and transfer from bed to chair. By avoiding cutting the muscles, it is possible to minimise the physical trauma of surgery, allowing a procedure with reduced blood loss and less procedure time. In addition, the end of the thighbone and in some cases the knee cap remain. These bones can support the body’s weight at the end of the remaining limb through the same mechanism as kneeling down. On the other hand, some surgeons think that problems with healing may be more common with this approach. It is unclear whether amputation through the knee may therefore be a better operation, allowing improved recovery, greater likelihood of being able to walk with an artificial leg, and better quality of life, or whether it is associated with worse outcomes due to wound healing failure and the need for further surgery. The aim of this review was to look at the best available evidence to see how these operations compare.
This review searched for studies that looked at whether through-the-knee or above-the-knee amputation resulted in better wound healing after amputation, improved patient survival, and reduced pain (clinical outcomes), as well as better rates of prosthesis use, walking speed, and quality of life (rehabilitation outcomes).
Study characteristics and key results
A thorough search of the available literature was performed (up to 17 February 2021) to find studies comparing through-knee with above-knee amputation. We identified no studies comparing these two procedures.
Certainty of the evidence
We were unable to assess the certainty of evidence because of the absence of studies included in this review.
Conclusion
Due to a lack of randomised trials, we are unable to determine if through-knee amputations have different outcomes from above-knee amputations. High-quality randomised controlled trials are required to provide evidence on this topic.
No RCTs have been conducted to determine comparative clinical or rehabilitation outcomes of through-knee amputation and above-knee amputation, or complication rates. It is unknown whether either of these approaches offers improved outcomes for patients. RCTs are needed to guide practice and to ensure the best outcomes for this patient group.
Diabetes and vascular disease are the leading causes of lower limb amputation. Currently, 463 million adults are living with diabetes, and 202 million with peripheral vascular disease, worldwide. When a lower limb amputation is considered, preservation of the knee in a below-knee amputation allows for superior functional recovery when compared with amputation at a higher level. When a below-knee amputation is not feasible, the most common alternative performed is an above-knee amputation. Another possible option, which is less commonly performed, is a through-knee amputation which may offer some potential functional benefits over an above-knee amputation.
To assess the effects of through-knee amputation compared to above-knee amputation on clinical and rehabilitation outcomes and complication rates for all patients undergoing vascular and non-vascular major lower limb amputation.
The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases; the World Health Organization International Clinical Trials Registry Platform; and the ClinicalTrials.gov trials register to 17 February 2021.
We undertook reference checking, citation searching, and contact with study authors to identify additional studies.
Published and unpublished randomised controlled trials (RCTs) comparing through-knee amputation and above-knee amputation were eligible for inclusion in this study. Primary outcomes were uncomplicated primary wound healing and prosthetic limb fitting. Secondary outcomes included time taken to achieve independent mobility with a prosthesis, health-related quality of life, walking speed, pain, and 30-day survival.
Two review authors independently reviewed all records identified by the search. Data collection and extraction were planned in line with recommendations outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We planned to assess the certainty of evidence using the GRADE approach.
We did not identify RCTs that met the inclusion criteria for this review.