Cow parts aid knee repairs

By MARTIN JOHNSTON health reporter

Surgeons are using purified cows' tendons to repair a knee injury that mostly affects athletes and older people.

The controversial and experimental technique, described to an Auckland conference, encourages the small shock absorber pads in the knee to regrow after they have been damaged.

Each knee has two "meniscus" pads, made of fibrous tissue, that cushion the rounded tips of the thigh bone from the flat-topped tibia.

They can tear during sudden, twisting movements, causing pain, swelling and giving way or locking of the knee.

The outer edges can heal well, but the insides fail to because they have less blood supply.

In the United States, an estimated 61 people in every 100,000 suffer an acute meniscus tear; 60 per cent of over-65s are thought to have a degenerative tear. The condition can lead to wear-and-tear arthritis.

Former All Black captain Sean Fitzpatrick, who lost a long battle against a bad knee, had part of a meniscus removed.

In the new technique, developed by United States surgeons, collagen tissue from the achilles tendons of dead cattle is purified and a small piece stitched into the patient to replace the torn section.

It acts as a scaffold on to which a new meniscus can grow.

The body gradually absorbs the cow collagen.

Orthopaedic surgeon Dr Bill Rodkey, of Colorado, presented results of implant trials to the Auckland conference of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine, which has attracted more than 1100 surgeons.

In a trial of 288 people, half received the new treatment and the rest had the damaged part of the meniscus removed.

Two years later they were checked against a 1-10 activity scale on which a score of 1 means a person can do little and those at 10 would be professional athletes.

Those with the implants scored on average 6. The control group averaged just over 4.

An earlier group of eight implant patients scored on average 3.4 before surgery. Six years later they were at 6, the level of a high-performing recreational athlete in sports such as downhill ski-ing or soccer.

Dr Rodkey, now 55, received an implant in his left knee in 1996 after suffering injuries, the first of which was slipping on ice.

"I'm doing great. I ski for about 50 days a year and I hike in summertime for two to three hours at a time and I cycle almost every day."

He said yesterday the suppliers of the implants, which cost about US$1500 ($2679) each, had just gained approval for their use in Australia and he hoped they would soon be available in New Zealand.

But the society's president and All Blacks orthopaedic surgeon, Dr Barry Tietjens, said many surgeons had expressed reservations.

"They don't think they work [and are concerned] about the material they are made from. It involves implanting protein from animals.

He questioned whether the implants were strong enough while the meniscus regrew, and "whether the thing you get at the end of it all is worth having".

Meniscus transplants from dead humans, also discussed at the conference, were a better prospect, he said, although they were not yet used in New Zealand.

Another option in the future might be to use a patient's own cells as a scaffold instead.