New range of prostheses continues success story

19 August 2002
"CAN you see which leg it is?" UCT senior lecturer Dr George Vicatos asks as the young man strides confidently across the doctor's room. We can't. The patient's stride looks normal, as do his legs. It's hard to believe the young man has a titanium implant replacing his femur and knee joint, having faced an above-knee amputation last year when a cancerous growth was detected in his femur.

Jonathan* (19), a former cricket player and ballroom dancer, is a student. Though he probably won't play cricket at a high level, or win ballroom dancing titles, he's walking on air, delighted with the way the prosthesis handles and by the opportunity to live a normal life.

At the time, the case sparked a dramatic tale of creative ingenuity. When it became apparent that the funding was not available to import a custom made endoprosthetic replacement for the young cancer patient to avoid an amputation, Vincent Pallotti Hospital surgeon (and part time at Groote Schuur Hospital) Dr Keith Hosking approached Vicatos from Mechanical Engineering to design a titanium "stem" to replace the cancerous part of the femur.

Working against the clock, Vicatos took his drawings to Len Watkins, Principal Technical officer in Mechanical Engineering, who machined the components. The tools used to implant the prosthesis, were completed the day before the operation. Vicatos and Hosking did a "trial run" the same night. In a lengthy and complicated procedure performed by Hosking, the tumour and two thirds of the femur and knee joint were resected and the implant successfully inserted. Within two weeks of the operation Jonathan was able to move his leg and hip and was "up and walking" within three months.

Building on this success story, Vicatos, Hosking and Watkins have collaborated to design a new range of various prostheses including a shoulder joint, a distal radius, a proximal tibia, a hip, as well as a complete modular system for the replacement of the femur. The new, modular design allows the surgeon (using simple tools) to assemble the correct length for the prosthesis inside the operating theatre, outside the patient.

"They are designed to be simple and to make the surgeon's job easier," Vicatos added. One of the latest designs is a complete humerus (upper arm) including the shoulder and elbow joints, which will be manufactured in association with the Cape Town-based foundry, CastCo Precision Castings (Pty) Ltd, the only local foundry that can cast the intricate shapes out of the material used for prostheses.

Because they are locally designed and manufactured, they are far more affordable than the imported overseas equivalent products, which, like Jonathan's femur, will give many other cancer patients a second chance.

In close co-operation with Hosking the designs are repeatedly revised. "Some parts are exceptionally difficult to manufacture at present and some others can be standardised and produced in various sizes and options in advance so patients need not wait. We're expecting in the future to manufacture the components much faster and with greater precision," Vicatos noted.

Many other patients have subsequently benefited from these specialised implants and research on new designs has been ongoing. This has only been possible by utilising the University's scientific knowledge and infrastructure, Vicatos noted. Several engineering students have become actively involved in this project under the guidance of the team. Vicatos praised UCT and Mechanical Engineering for the support the project had received. "The University has allocated space in the Old Maintenance Building to set-up the manufacturing unit".

Additional funding is urgently needed to facilitate research, development and purchase of the expensive equipment needed to continue providing this valuable service.

Isiqu, the Xhosa word for "complete body" is the name that the team has chosen for their research and manufacturing unit within the University's Upper Campus.

(* Not his real name)

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