Have you ever had a serious knee injury and asked yourself what do I do now?
Have you been told you have damaged your ACL?
Ever wondered why it is so important to repair the ACL post injury?
Over the past couple of months we have had a number of new Anterior Cruciate Ligament (ACL) injuries present to the clinic and thus a number of patients currently undergoing either ACL prehabilitation or rehabilitation!
The evidence surrounding ACL injuries is rapidly changing and the questions regarding best practice have changed over the last 10 years. This blog will look at some of your most frequently asked questions and maybe change your opinion on ACL injury!
What is the ACL and what does it do?
The ACL is one of four major ligaments in the knee. It attaches between the femur (thighbone) and the tibia (leg bone). Its main role involves preventing anterior translation (forward movement) of the tibia on the femur. It is most commonly injured in non-contact sports when the foot is planted and the sportsperson is attempting to pivot or change direction.
There is a higher incidence of rupture in females which is thought to be due to differences in lower limb alignment (due to wider hip-knee angle), increased ligament laxity as well as differences in muscular strength and neuromuscular control.
What will I feel if my ACL has ruptured?
At the time of injury you may have extreme pain or you may have no idea that you have a knee injury at all. Often you may hear a ‘pop’ at the time of injury and will usually have immediate swelling. This swelling can stay present from days to weeks post injury. You may also have feelings of instability or ‘giving way’ and will have difficulty changing direction during running. Due to the increased swelling and inflammation it may be difficult to bend and straighten the knee which will also result in increased pain in the area.
The symptoms that present can differ greatly depending on whether the ligament is completely ruptured or just strained, concurrent injuries of other knee structures such as the collateral ligaments or meniscus and the individual body’s responses to injury.
Can I walk without an ACL? And can I play sport without an ACL?
Most patients will find they can walk relatively well days to weeks post injury and sometimes even on the day of rupture. You may even feel like the knee is almost back to normal but are unable to perform higher function activities such as pivoting or landing from a jump. Some patients will have great difficulty walking post injury due to the increased swelling, pain and lack of stability in the knee. You may require crutches for a few weeks post injury to ensure proper gait is achieved and to prevent secondary complications from walking with a limp.
The idea of returning to sport without an ACL is becoming more popular with available evidence showing it can be done. The question of whether to undergo surgery or not will be looked at later in this blog but yes it is possible to return to sport without having an ACL reconstruction.
The risk of avoiding reconstruction is an increased likelihood of damaging the meniscus. We also know that injury to the meniscus increases the chance of knee arthritis later in life. Therefore the decision of whether or not to undergo surgery should be discussed with your physio and specialist.
How do I know if it is ruptured?
If you suspect your knee injury is serious and you may have damaged a ligament you should see your physiotherapist who will assess your knee and perform some specific tests to determine whether there is any damage to the ACL. If they are concerned they will send you for an MRI to confirm the injury and extent of the injury. This scan will also show if there is any involvement of the other structures in the knee. This could include bony fractures, torn meniscus, collateral ligament damage and articular cartilage damage.
In young patients the ACL may not rupture but can pull a fragment of bone off the tibia. It is very important to diagnose these injuries as this type of injury can be treated surgically without reconstruction.
MRI of a ruptured ACL shows an obvious rupture in the ligament. The ligament should be taught with no disruption of the black line as seen on MRI.
I’ve seen a surgeon and have decided to have a reconstruction … now what?
Studies show that good prehabilitation gives better post-op results and more effective rehabilitation. Therefore it is very important to start your physio soon after injury!
Goals of prehab include:
- Full knee range of motion
- Optimal strength – ideally right = left
- Pain free knee joint
- Reduction of swelling around the knee joint
- Ensure prior healing of other damaged structures within the knee joint eg. MCL
- Learning post-op exercises which has shown to benefit the patient after surgery
- Normal gait (walking)
Your physiotherapist will give you a range of exercises aimed at achieving these goals which will get you ready for surgery.
I’ve decided not to undergo surgery… what next?
Not everyone who has ruptured their ACL requires a reconstruction. This decision depends on your age, the level of sport you are playing and the physical demands of your job or sport, the future demands of your knee, functional instability and the extent of the injury among other personal factors. A patient with an ACL deficient knee along with functional instability is it at high risk of further knee damage.
Your knee will still require an intense rehabilitation post injury to limit the likelihood of further injury. This will include:
- Manage pain and swelling
- Regaining full range of motion
- Strengthen the surrounding muscles (quads, hamstrings, calves, glutes)
- Improve proprioception and balance
- Improve technique, biomechanics and lower limb function to prevent further injury
When should I have my ACL reconstruction?
It is well known that knees that are pain free and have a good range of motion are better off post surgery. Therefore it is important to undergo some prehabilitation to achieve these goals. As it is not necessary to have an ACL during everyday activities it is possible to wait until your circumstances best suit eg. work holidays. For patients that have damage to other structures and are grossly unstable or are experiencing ‘locking’ of the knee will often have to undergo surgery earlier to avoid further damage to the knee.
What can I expect post-op ACL reconstruction?
Post-operatively you will most likely see a physiotherapist in the hospital who will give you 1 or 2 simple exercises and teach you how to use crutches if required. From this point you will attend physiotherapy in the clinic and this could be up to a couple of sessions a week, depending on your objective measures, and progress to once a month.
The following is an example of what your rehabilitation may look like. This is only a guideline and depends on the individual reconstruction and surgeon’s guidelines for your knee. Each body is different and will progress through the rehabilitation differently. Your physiotherapist will guide you through your rehab depending on your progression and individual goals.
Goals for the first 2 weeks may include:
- Managing pain and swelling
- Restoring full knee extension range of motion
- Establishing muscle control – particularly of quadriceps and hamstrings
- Progress to normal weight bearing and wean crutches as able
Goals for weeks 2-6 may include:
- Improve muscular control in more weight bearing positions
- Improve proprioception/balance (the body’s perception of where it is in space)
- Restore normal walking technique
- Begin to increase muscular strength (quadriceps, hamstrings, glutes, calves)
Goals for weeks 6-12 may include:
- Begin strengthening in more complex movements/positions
- May begin strengthening work in the gym
- More dynamic proprioception work
- Increase muscle endurance capacity
- Improve cardiovascular fitness
- May begin straight line jogging during this phase
Goals for 12 weeks to 5 months may include:
- Further strengthening with higher demand (endurance, power, strength)
- Begin sports specific type activities (targeted at individual sporting demands)
- Begin agility and more complex proprioception work (hopping, jumping, lateral movements)
- Improve confidence in the reconstructed knee with progressive work of greater intensities and difficulty of movement
What does the surgery involve?
Generally the procedure is performed as day surgery and a general anaesthetic is used. The procedure will depend on the type of graft used (hamstring, patella, LARS), which is a decision usually made between you and your surgeon
The most common graft used is the hamstring tendon and it is removed from the back of the leg through an incision which is made at the front of the knee. An arthroscope is used to allow internal access of the knee and the extent of damage to other structures is examined and addressed. The ruptured ACL is then either removed or left in place to suture the new graft to depending on the technique used by your surgeon. Tunnels are drilled into the tibia and femur at the site of ACL attachment. The previously removed hamstring tendon is then pulled through these tunnels and fixated with screws, buttons or staples. The wounds are then closed and a bulky dressing applied. You will walk out of hospital on the same day with the use of crutches.
When can I return to sport post reconstruction?
This is probably the most frequently asked question for any patient who is undergoing an ACL reconstruction. There is a range of timeframes given by surgeons for when this goal can be achieved. Most therapists these days will base this decision not only on a time contingent but by the functional capacity of the patient. Thus progressions should be based on goals achieved in relation to function rather than say progress to this exercise by week 6.
Most rehab protocols will allow return to contact sports by around 9 months post-op thus allowing enough time for the ACL to biologically heal. Studies have shown that there is a 50% reduction in knee injury risk for every month return to sport is delayed after 6 months, up to 9 months.
To be eligible to return to play the athlete must complete a set number of functional goals such as the ability to singe leg hop, pivot, land from a jump etc. The operated knee should have a maximum difference in testing of about 10%. Thus the operated leg should be at least 90% capacity of the un-operated leg. This includes objective testing of quadriceps and hamstrings strength, agility, proprioception and neuromuscular control.
In summary, there a number of factors that should be considered when returning to sport. Simply waiting 12 months and then running back on the field is a surefire way to re-rupture the ACL or injure another part of the knee. You need to ensure the knee is objectively stable, you have passed functional testing, allowed sufficient time for graft maturity, have 90% strength, proprioception and neuromuscular control and be psychologically ready for return to play.