The pioneering new treatment helping heal the most common knee injury

Each year, millions of people around the world tear or sprain their anterior cruciate ligament (ACL). The most common knee injury, it typically happens while people are skiing, playing football, basketball or netball.

The 24-year-old was playing Oz Tag at a football field in Sydney’s Sutherland Shire, when she stepped into a large divert in the grass. She felt a shock of pain and a “pop” as her knee slid in the wrong direction and her leg gave way.

Mead, who was playing elite AFL at the time, had seen many of her teammates tear their ACLs (the injury is up to eight times more common in women). She knew it didn’t have to be a career-ending injury – after surgery, about 65 per cent of people return to their former level – but it did mean surgery and sidelining sport for at least a year.

Mead had already booked her surgery when a friend suggested she speak to sport physician and former Sydney Swans doctor Tom Cross.

“My friend was like, ‘Look, I don’t know if this will help or not, but just go have a chat with this guy’.”

Eight years earlier, Cross had been treating a 19-year-old who had ruptured her ACL while playing netball. The standard treatment was surgery, but the woman pressed Cross for another option, as close friends of hers had ended up with another tear after their operations (between 8 and 30 per cent of people re-rupture following surgery).

Cross’ father, Merv, a retired orthopedic knee surgeon, happened to be in the clinic receiving treatment for his own knee injury. Merv overheard the conversation and pulled back the curtain with an idea.

By bending the knee to 90 degrees and immobilising it in a brace, Merv suggested you could bring the torn ends of the ACL closer together allowing them to heal similarly to a bone fracture.

Tom thought it was a bit crazy – no one took the knee past 30 degrees when trying to heal a knee ligament injury – but he trusted Merv, a pioneering knee surgeon with 40 years’ experience who was also director of orthopaedics for the Sydney 2000 Olympics.

The patient thought she had nothing to lose. If it didn’t work, she could still have surgery. So, for four weeks, they put her knee in the brace, locked at a right-angle. Over the next two months, they incrementally straightened the leg back out, gradually putting more weight on it. Three months after this crazy experiment, MRIs revealed “exuberant healing”.

More than 1450 patients later and a 90 per cent success rate, the cross-bracing protocol (CBP), as it came to be known, is becoming a “revolutionary” new approach to treating ACL tears.

Cross explains that