Cape lecturer develops knee implants that fit like a glove

A LECTURER at Stellenbosch University has found a way to create knee implants that fit patients with arthritis like a glove.

His work could end up helping millions of patients in the next decade.

“People whose knees have been affected by osteoarthritis‚ also known as the ‘wear-and-tear’ arthritis‚ often have to get knee implants to repair the damage,” the university said in a statement yesterday.

“But if a knee implant does not fit the specific individual‚ it could lead to soft tissue damage‚ collapsing of the underlying bone‚ loosening of the implant and an increased likelihood of joint pain after an operation.”

Dr Johan van der Merwe‚ a lecturer in the department of mechanical and mechatronic engineering at Stellenbosch‚ said: “One possible solution is to design implants that are patient-specific‚ anatomically accurate‚ reproduce normal knee motion and are ultimately repeatable.”

Van der Merwe developed a semi-automated method of generating patient-specific implant components.

“Replacing or repairing only the damaged part may result in faster recovery‚ improved post-operative joint movement‚ retain as much of the joint’s natural anatomy as possible and be done at a lower cost‚” he said.

“But designing patient-specific Unicompartmental Knee Replacements ultimately relies on a technician’s interpretation and skill to consistently reproduce healthy knee shapes.”

Van der Merwe said standardised implants often did not match the shape of an individual patient’s knee‚ which might require surgeons to “make the patient fit the implant”.

His semi-automated design programme fits smooth surfaces onto the estimated healthy shape to create implants ready for computer-assisted manufacturing.

“We hope the design could facilitate the restoration of more normal joint function after an operation‚” he said.