Quantifying wound pressure thresholds in lower limb amputees

Year Submitted: 2025
Published Date: 06 May 2025

Tags: Digitalisation, Technology

About this Content

Aims

1. To evaluate if peak pressure reduction assists in resolving wounds, redness and pain inside prosthetic sockets in people with transtibial amputation
2. To determine if peak pressures measured inside the prosthetic socket due to external forces could be used to quantify the level of improvement in socket discomfort.

Background

Amputation rates are rising globally in part due to the increase in diabetes. Singapore has one of the highest rates of diabetes in the world. Over 700 amputations are performed annually in Singapore as a result (Nather et al, 2010). New technologies and innovation have led to considerable improvements in prostheses however patients are still dissatisfied with the comfort of them. Comfort is subjective but is essentially measured between the socket and the patient’s stump. The socket fit, type of suspension and alignment of the prosthesis can dramatically affect the levels of comfort by altering pressures within the prosthesis. Biomechanical knowledge of the behaviours between the socket and the skin leads to improved functional outcomes and increased satisfaction scores. Almost all patients report discomfort in the socket due to oedema, skin irritations or pressure ulcers.
Understanding interface pressures will allow for a more comfortable socket to be produced for the patient. A subset of this will be improved outcomes, functionality and self-esteem. The introduction of sensors to measure peak pressures and determine whether a common threshold occurs for wound development is the first step in quantifying the levels of patient tolerance here in Singapore. This is new research and has not been done on any group in the world. Research currently exists in quantifying some pressures that occur within the socket as a patient walks or runs but there is a lack of information on prevention of wounds or abrasions.

Methods

Participants with wounds, redness and pain were recruited in an outpatient setting at TTSH. A load sensor was placed over the problem areas and peak pressures were measured. The socket comfort score was used to quantify their comfort levels. Following adjustments to the socket, subsequent readings from the load sensor were used to quantify the amount of pressure reduction and corelated to the socket comfort score which was asked a second time after the adjustments.

Results

The peak pressure value showed a statistically significant reduction across all participants following adjustments at a 50% delta change in pressure (p=0.001). This was achieved with a mean number of 2.6 adjustments per participant. Following the adjustments, the paired T-test results showed a mean increased between the first socket comfort score and final socket comfort score was 2.625 (p=0.001).

Conclusion

The wound, redness and pain resolved in over 90% of participants regardless of diabetic status following socket adjustments. The peak pressure reduction following adjustments should significant improvement to the socket comfort score. The user of a portable sensor is a fast and efficient means to quantify adjustments inside the prosthetic socket and could potentially be considered as part of future care delivery.

Lessons Learnt

This project needed the use of a suitable sensor that was thin and washable with overall good durability. It took time to determine the correct sensor and even more time to go through purchasing. It is good practice to plan ahead of time in anticipation of such delays.

Additional Information

This study was published in the Physical Medicine and Rehabilitation journal in 2023.

Keywords

Prosthetics and Orthotics, Sensors, Product Evaluation

Innovators' Details

Connect with this contributor!

Trevor Binedell - Trevor_binedell@ttsh.com.sg ↗ (opens in new tab)

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