Hip disarticulation - the future

For insurers, a case involving hip disarticulation surgery brings the challenging prospect of an expensive claim which may well go on for many years. Hip disarticulation surgery involves amputation of the lower limb through the hip joint and is considered to be one of the most extreme and complex forms of lower limb amputation. Most often it is performed following a major traumatic incident or spread of infection of the lower limb, typically seen as a form of life saving surgery.

Claimants who undergo this form of amputation usually endure intensive physiotherapy and rehabilitation both post amputation and pre and post prosthesis. The prosthetics themselves can be problematic and impractical. The prosthetic is used as a replacement for the hip, knee and ankle joint, walking therefore is not only more troublesome but with it brings a greater risk of prosthetic rejection.   

For insurers, these claims can be extremely expensive. Fortunately, they are a rarity.  

In the past, the quality of life in these amputees was regarded as modest. However, the technological advancements for hip disarticulation prosthesis conveys a brighter future for these individuals.  

Conventional prosethesis

The traditional prosthesis was developed by Colin McLaurin in 1954 and is referred to the ‘Canadian’ type prosthesis which uses free hip, knee and ankle joint with a moulded socket enclosing the ischial bone for weight bearing with a broad integral belt gripping the pelvis.

Thereafter, the “lightweight bikini type hip socket”1 was developed by Martin Bionics Prosthetics and Research which was regarded as a more lightweight design allowing patients to bend forwards with little difficultly whilst wearing the prosthesis but also offer greater comfort. Helpfully it only weighed a third of the weight of conventional bucket type sockets.

In more recent years, we have seen the Helix 3D prosthetic hip2 which uses 3D pelvic rotation to imitate the normal movement of the human body, therefore providing a more natural walk and greater comfort. The hydraulics allow for greater flexion of the hip which provide ease with bending and participating in day to day activities as well as stride length which can be tailored to meet each individual. The 3D prosthetic hip is fitted alongside a microprocessor controlled prosthetic knee and a separate Triton foot which reduces the risk of falling.

The future and robotic prosthesis

The development of robotic prosthesis for hip disarticulation patients is still very much in the prototype stage. Developing these prostheses is more challenging than developing prostheses for other types of amputees as these individuals have less muscle, more reduced motor function, problems with gait and require the hip, knee and ankle joints to work together to allow the individual to walk. Yuki Ueyama from the Department of Mechanical Engineering in Japan has carried out a trial into the robotic hip disarticulation prostheses. In his study he states, “The robotic prosthesis is powered by two motors at the hip and knee joints”3 a battery pack and generates walking motion to follow the non-prosthetic limb. The ankle joint is a non-powered foot. The battery pack is attached to a waist bag worn by the individual. The prosthesis is then attached to the custom made socket for that individual which is tightened around the waist.

Although still in the experimental stages, the study found that the robotic prosthesis enhanced step length compared to a non-powered prosthesis and maintained symmetry of the legs, thus allowing the leg to swing forwards and backwards with ease. In fact, the suggestion is that it could generate gait similar to that of a healthy person, provide a lesser physical burden of walking and require minimal training, consequently improving quality of life. In addition, the robotic prosthesis could eliminate the risk of rejection as well as reduce forward leaning which was often the case with the traditional prosthesis.  

Whilst it could be revolutionary for these amputees, the robotic prosthesis was found to be much heavier than your standard prosthetic, weighing 11.3kg. That being said, with the ongoing advancements in technology the study found that there may be scope for a more lightweight prosthesis in the future.  
  
In the personal injury world we are now starting to see a greater variety of robotic prosthetics for amputees, including the robotic prosthetic leg and the development of the robotic prosthetic arm. The implementation of robotic prosthesis for hip disarticulation amputees is much more challenging given the nature of the amputation and whilst the initial indication is that it will benefit the individual, there are concerns. Its weight being one, as well as its complexity which may make it more cumbersome  to use. In some cases, we may find that older claimants prefer a simpler, more lightweight prosthetic. In addition, there are many unknowns i.e. will it have the longevity needed, will there be greater maintenance costs? At this stage, whether the costs for insurers will outweigh the benefits remains to be seen. 

1 https://martinbionics.com/hip-disarticulation-bikini-socket/

2 https://www.ottobock.co.uk/prosthetics/lower-limb-prosthetics/prosthetic-product-systems/helix_hip_system/

3 https://www.tandfonline.com/doi/full/10.1080/01691864.2019.1705908?scroll=top&needAccess=true

This content was written by BLM prior to its merger with Clyde & Co.