Made-to-order knee implants at Tan Tock Seng Hospital

Dr Sathappan with his patient, retiree Wong Took Lim, who underwent surgery last month for a custom implant for his left knee. Custom implants are moulded to give the perfect fit using 3-D printing technology.
Dr Sathappan with his patient, retiree Wong Took Lim, who underwent surgery last month for a custom implant for his left knee. Custom implants are moulded to give the perfect fit using 3-D printing technology.PHOTO: KUA CHEE SIONG

Custom implants give perfect fit but cost twice as much as generic ones

Bespoke knees are now available at a hospital near you.

For the past month, Tan Tock Seng Hospital (TTSH) has been performing knee replacements for patients using custom implants.

Unlike generic knee implants, these are moulded to give the perfect fit using 3-D printing technology. "It's like tailoring a shirt, rather than looking for the shirt that best fits you," said Adjunct Assistant Professor S.S. Sathappan of the orthopaedic surgery department. "They are custom-made for (the patient's) size, shape, and body mechanics."

The number of people needing knee replacements at the hospital has been increasing by 10 per cent every year.

Last year, around 600 underwent the procedure, which is typically for people who have osteoarthritis. This painful condition occurs when cartilage between bones - at joints such as the knees or hips - wears down.

During surgery, metal implants replace this cartilage, preventing the bone surfaces from rubbing against each other.

Generic implants come in different sizes but patients' knees sometimes come in "in between" sizes that are not a good fit for any available implant, according to Dr Sathappan. Implants also tend to cater for bigger-boned Western patients.

"For some patients, the implant is just a little bit big, and that's already the smallest size we have," he said.

However, generic knee implants will still be the first choice for many as custom implants cost about twice as much.

Dr Sathappan generally recommends the latter to patients who have medical issues - for example, a heart condition - that necessitate speedy surgery.

Patients who opt for custom implants must undergo a CT scan. There is then a six-week wait for surgery while the images are sent to the United States and the finished implants are delivered.

Mr Wong Took Lim, 72, underwent the procedure and was billed around $10,000 for the operation - excluding ward and rehabilitation fees. The retired senior clerk and active sportsman began to feel pain in both knees around 25 years ago, but kept it in check through injections.

He underwent a partial knee replacement with a generic implant for his right knee two years ago, then had a custom implant for his left knee last month.

"Now it feels like I'm carrying two bags of sugar on my leg," he said, flexing his left knee. "But I'll get used to it - just like the right knee. I have no regrets because the pain would only have got worse with the passage of time."

linettel@sph.com.sg