Projects
Hydrostatic Casting in Prosthetics
2022 Extraordinary Opportunities Grant
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Project description
To assess whether introducing a hydrostatic pressure casting system for prosthetic legs reduces the need for multiple fitting appointments and the time required for socket manufacture, allowing patients at Royal Brisbane and Women’s Hospital to begin prosthetic training sooner.
Why this is needed
Socket fit is vital to the comfort, suspension, control, and acceptance of a lower extremity prosthesis. The biggest challenge for the practitioner is to consistently and accurately capture limb contours and tissue displacement as they would under load.
All prosthetic patients at the RBWH and its outreach clinics are cast for their prosthesis using traditional hand casting techniques. This has limitations in terms of capturing the likely pressures of a prosthetic socket under weightbearing load. More recently, hydrostatic pressure casting systems have been developed which allow for more even load and distribution through casting.
Hydrostatic pressure casting is an innovative technology that accurately captures a limb's anatomy under full weight bearing conditions. During the casting process, the patient rests their affected limb on a silicone membrane, inserted into a cylinder filled with water.
Optimal hydrostatic (water) pressure is then applied to the limb while in full weight bearing, allowing sensitive areas, bony structures, pressure and pain points, to be identified. The plaster impression and the subsequent socket consequently adapt and fit to the anatomy of the residual limb.
Increased accuracy eliminates the need for cast modifications and enables the practitioner to efficiently provide the patient with a comfortable, well-fitting socket.
An ill-fitting socket can create a myriad of problems for a prosthetic user such as wounds or blisters, pain or injury to the affected leg and decreased prosthetic use.Expected outcomes
The RBWH Prosthetics department manufactures transtibial prostheses for over 100 patients a year. These patients are required to remain within the service until they are safely mobilising on their prosthesis. For many patients, this requires between 10-12 prosthetic appointments over 9-12 months. This places considerable strain on these patients who are often reliant on family/friends for transport to RBWH.
A hydrostatic pressure casting system would potentially reduce the number of prosthetic appointments by half. Furthermore, the casting system would potentially lead to a reduction in patients presenting to wound clinics and vascular clinics with skin issues relating to poor prosthetic fit.
Meet the Project Leader
Andrew MacDonald
Orthotist/Prosthetist
RBWH Orthotics and Prosthetics
Andrew MacDonald
Andrew MacDonald is a qualified prosthetist/ orthotist and has worked at the RBWH for the past 5 years. During this time, he has worked in both an acute and rehabilitation setting with a particular focus on interim prosthetic management.
Andrew completed his training in 2018 before being awarded a Queensland Health scholarship to begin practicing at the RBWH. During his studies he was fortunate enough to complete training both domestically as well as abroad. Completing part of his training in Ireland provided him the opportunity to observe complex prosthetic and orthotic cases at a nation leading facility.
Whilst at the RBWH Andrew has led a quality improvement project implementing the use of pressure mapping in orthotic management. This project focused particularly on using pressure mapping to investigate the role of insoles in offloading pressure wounds in a diabetic population. Furthermore, he has contributed to a project presented at the International Society for Prosthetics and Orthotics investigating the incidence of adverse outcomes in Halo management.
Now in a primarily prosthetics role, Andrew enjoys working with amputees through the initial phases of their rehabilitation; ensuring they can return to the activities that they enjoyed doing prior to their amputation. He believes that developing and implementing innovative approaches to prosthetic care is at the forefront of ensuring that patients receive the best prosthetic treatment possible.
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