Anterior Cruciate Ligament Injury.

The ACL is a ligament that provides stability to the knee. This is most required during high-speed movements that involve deceleration and changing direction. The ACL is at most risk when muscle fatigue occurs.

 

It is possible to return to sports without a functioning ACL but your knee has a higher likelihood of incurring recurrent meniscal/cartilage tears. Should the knee experience giving way - each episode of instability may further damage the knee leading to early arthritis and knee pain.

 

Should you not develop instability after an ACL injury and you manage to keep your muscles that support the knee strong, then you may be able to avoid surgery.

It is however common to require ACL reconstruction; if you want to return to sports that involve changing direction or twisting on the knee or if you are a jumping/landing athlete such as netball/basketball/skiing/footy/Oz tag your ACL is required to help stabilize the knee.

If you have meniscal injury at the same time as your ACL injury, Dr Fleming may suggest early ACL reconstruction when addressing the meniscal tear.

If the MCL has been damaged and there is no severe meniscal tear then a period of 6 weeks in a collateral support brace will allow the MCL to heal prior to undergoing ACL reconstruction.

Timing of ACL recon

If possible, there is evidence from studies highlighting a lower likelyhood of failure if ACL reconstruction is delayed until which time your knee has regained the range of movement and the knee is less inflamed from the original injury.

A large recently published study published by Dr Gregory Maletis from the USA shows the following:

If ACL reconstruction is performed within the first 3 weeks after injury risk of failure over 6 years is 12.9%, if performed between 3 weeks and 3 months this failure rate reduces to 7% and if performed after 3 months the failure rate falls to 5.1%. - Knee Surgery, Sports Traumatology, Arthroscopy Feb 2022

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What does an ACL injury mean to my short-term sporting ability?

An ACL injury is a serious condition that will change your knee function for the remainder off your sporting career.

Should you require reconstruction it is important to undergo a complete physiotherapy rehabilitation course - this is a specialised area that may best be performed by physiotherapists who perform this regularly.

The rehab is divided roughly into 4 stages.

Stage 1 - Prehab: After the initial injury you’ll need to settle the swelling in the knee and regain both your quad strength and range of motion as best possible before undergoing surgery. If you damaged your MCL/ Medial Collateral Ligament this will need to be braced with a range of motion brace for at least 6 weeks to allow this to heal before surgery.

Stage 2 - Post-op: for the first 2 weeks you need to work on swelling control with ice compression elevation. The important aspects to get on top of are regaining full extension (straightening) and quadricep activation. You need to work on being able to straight leg raise without any lag.

Stage 3 - Week 2 to week 12: controlled strengthening with any surgeon-imposed limits decided on at surgery. The stage usually has no impact or running.

Stage 4 - 3 months to one-year post-op: This will include the reintroduction of running when your knee swelling has subsided. Neuromuscular training is essential to manage with the demands of your sports when you return to the field. Your ACL graft takes a long time to get to achieve its full strength in fact it takes 2 years to achieve full maturity. During this period, you are at a higher risk of recurrent ACL injury so it is imperative to complete your physiotherapy to minimize your risk of the surgery failing.

Types of ACL graft

There are numerous graft choices one can use when planning surgical reconstruction.

Hamstrings tendons may be used from the same leg, the central portion of your patellar tendon with a block of bone from your patella/knee-cap, part of the quadriceps tendon, a single hamstring may be selected in favour of preserving the remaining hamstring. Allograft tendon from a donor may be used. All these choices have different benefits and downsides.

The choice of graft may be individualised to your knee and your requirements. For example, athletes who rely on their hamstrings (such as AFL footballers or soccer players) may benefit from using grafts other than their hamstrings to preserve their strength and function.

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Lateral extra-articular tenodesis (L.E.T.)

If you have a particularly unstable knee or if you have a high risk of recurrent injury, Dr Fleming may choose to perform an additional lateral procedure. This procedure has been shown to provide a protective effect for ACL grafts in the setting of high-grade pivot shift instability. There will be an additional scar on the outer aspect of the knee and a slightly slower recovery during the first 8 weeks, it is usual that the outer aspect of your knee will feel a bit tight and your knee may lose some hyper-extension after the procedure.

Is swelling normal after ACL reconstruction?

It is normal during the first year after reconstruction to have swelling and occasional tenderness. The swelling will mostly occur after exercise or working long hours whilst standing upright.