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Anterior Cruciate Ligament (ACL)

What is an anterior cruciate ligament rupture? 

– The anterior cruciate ligament is one of the major knee stabilising ligaments. 
– ACL ruptures occur commonly during sporting activities due to a rapid change in direction, deceleration, or an awkward land from a jump. 
– The anterior cruciate ligament is one of the most injured ligaments of the knee.

What is the incidence of ACL ruptures in Australia? 

– Australia is a sporting nation and today has the highest reported rate of ACL injury and reconstruction in the world, according to recent research from the Medical Journal of Australia.
The study of 200,000 ACL surgeries found the incidence of ACL injuries increasing 74% in the past 15 years.ACL tears are up to 10 times more common in women, who fall differently to men, have wider hips (altered lower limb alignment) and increased ligament laxity.
The menstrual cycle also makes injury more likely on days 9-14 pre-ovulation. 

Who gets ACL ruptures? 

– ACL ruptures are the three most dreaded letters in the alphabet for many sports players, which no doubt Roosters forwards Victor Radley, and Sam Verrills will attest after devastating season ending ACL injuries.
– A 2021 scientific analysis of the Newcastle Knights found that ACL ruptures were by far the injury that resulted in the longest time away from sport for league players.

What are the symptoms of an ACL rupture? 

– An ACL rupture is a plant, pivot pop injury – and only occurs when the foot is in contact with the ground. A loud “pop” or a “popping” sensation in the knee is often heard during a pivot
Severe pain like this as experienced by tennis star Bethanie Mattek Sands when she tore her ACL 
– Difficulty walking 
– Swelling that begins within a few hours
– Loss of range of motion or movement 
– A feeling of instability or “giving way” with weight bearing.

How is an ACL rupture diagnosed? 

– Typically the two main tests used to diagnose an ACL rupture are the Lachman’s test shown here and the Pivot Shift test shown here.
– MRIs are the gold standard of imaging for an ACL injury however sometimes they can miss an ACL rupture if the ligament attaches to the nearby PCL, which is why the tests above help confirm a diagnosis but are not 100% accurate. 
– Suspected ACL injuries should go to a surgeon for assessment initially.
– Minor tears (sprains) may heal with non-surgical treatments (especially if the patient’s activities do not involve making pivoting movements on the knee).
– However complete ruptures with instability generally need surgery, which is why a surgeon should be consulted earlier rather than later.

What happens if ACL surgery is delayed? 

– A young athlete who returns to pivoting sports such as basketball, tennis, soccer, and football after only having undergone physical therapy rehab despite a confirmed significant ACL rupture with ongoing instability is at high risk for serious injury to the meniscus or cartilage – especially when ACL surgery is delayed.  
– For serious athletes, this is a big concern and new research in Science Daily in 2021, shows that of all ACL injuries, 35% of injured athletes will reinjure the knee when they return to sport. 
– This could result in a longer duration of time away from the game they love than if the ACL rupture was surgically treated in the first place.
– Early treatment makes a big difference and generally surgical reconstruction is very successful if done before any permanent chondral or meniscal damage occurs.

What happens in an ACL reconstructive surgery? 

– The ACL is replaced using either the patient’s own tendon (auto graft from the hamstring or patella tendon) or that of a cadaver’s (allograft).
– The procedure is usually a day surgical procedure called an arthroscopy.
– However, the reconstructed ligament matures over a one-year period so return to sport requires intensive rehab and patience. 

What is the accelerated rehabilitation program that Dr Herald advises post-surgery? 

– Dr Herald’s surgical protocol for ACL reconstruction can be found here. 
– Rugby player Adam Ashley Cooper can be seen here using the accelerated rehabilitation protocol that Dr Herald uses. 
– The reconstructed ligament takes up to a year to fully integrate so a commitment to a post-op rehab and ACL injury prevention.
– Dr Herald also recommends programs like the Santa Monica PEP program here for ongoing rehab and tear prevention. 
– These programs usually include exercises such as lunge walks, calf raises, scissor jumps and shuttle and pivot runs.
– Individual sports are also starting to offer special exercises to help train the musculature around the knee to compensate for the torn ACL and stabilise the joint. For example, Netball Australia’s Knee Program offers great knee exercises to prevent ACL damage.