Every year around 3% of amaetuer athletes injure their ACL, for professional athletes this can be as high as 15%. Pivoting sports such as football have the highest incidence of ACL injuries followed by winter sports like skiing. This is due to the fact that a cut-and-plant movement is the typical mechanism that causes the ACL to tear, this being a sudden change in direction or speed with the foot firmly planted. Rapid deceleration moments, including those that also involve planting the affected leg to cut and change direction, have also been linked to ACL injuries, as well as landing from a jump, pivoting, twisting, and direct impact to the front of the tibia.
Injuries to the ACL can range from mild injury e.g. a sprain of the ligmant to a full tear of the ligmant. mAYBE MOST SURPRISINGLY Females are 5 times more likely to sustain an ACL injury than their male counterparts. Acl injuries are relatively common injuries that we see in clinic at Movement perfected. Our job is to either prevent and ACL injury trhough exercise or to rehabilitate post injury or surgery.
ANATOMY OF THE ACL
The anterior cruciate ligament connects the thigh bone (femur) to the shin bone (tibia) and crosses in front of the posterior cruciate ligament (PCL). The ACL provides approximately 85% of the total restraining force of anterior translation. It also prevents excessive tibial medial and lateral rotation, as well as varus and valgus stresses.
The ACL’s primary role is proprioceptive in function due to the presence of mechanoreceptors in the ligaments- due to this the ACL injury is therefore regarded as a neurophysiological dysfunction and not as a simple peripheral musculoskeletal injury. As a consequence of its complex role in the kinematics of the knee, when an ACL injury occurs there are both clinical signs and subjective instability and therefore a comprehensive rehabilitation program is needed.
Prevention of ACL tears
Prevention of an injury is always the ideal; however, so many of the risk factors identified with ACL injuries are non-modifiable such as age, gender and history of previous injury.
Generally, the best thing to do especially if you participate in sport with a high incidence of ACL injuries is to work on mechanics and strength in hopes of avoiding non contact injuries
You cannot plan for contact injuries, but if you work on hamstring strength, hip mobility, and landing mechanics that is a great place to start. A physiotherapist will be able to come up with a specialised programme for you in this instance. People often don’t realise that the hamstrings are the secondary stabiliser to the ACL so it’s fundamental that the hamstrings are strengthened in order to provide the best possible stability. Similarly the importance of quad strengthening post operatively as well as a preventative meausre cannot be underplayed in the management of ACL injuries.
The Movement Perfected Team are trained to assess and treat ACL INJURIES CONSERVATIVELY AND POST OPERATIVELY.
The major goals of general rehabilitation of the ACL are:
- Gain full ROM of the knee
- Repair muscle strength and proprioception
- Gain good functional stability
- Reach the best possible functional level (walking, running, jumping…)
- Decrease the risk for re-injury
- (Return to sport)
A study by Grindem at al ( 2016) showed that with every one percent point increase in strength symmetry between the injured and non inujred leg, there is a 3 % reduction in reinjury rate. Similarly the same principle applies when there is more time between surgery and returning to sport after an ACL repair- most of the evidence points to returning to sport after 12 months of a comprehnsive rehabiliatiion plan to avoid re injury or re rupture of the ACL.
Type of ACL injuries and when to opt for a conservative or surgical intervention.
Injuries to the ACL can range from mild (such as small tears/sprain) to severe (when the ligament is completely torn). When an ACL has a complete rupture and there are clinical and subjective signs of instability, a surgical reconstruction is often needed- but not in all cases. Careful management and consideration of each ACL case should be discussed with the physio and orthopaedic surgeon before deciding on an ACL repair or not. ACL rehabilitation is always required for both for conservative (non surgical) and surgical options for optimum outcome and the importance of a good prehabilitation/rehabillitation programme cannot be underestimated.
Conservative VS Surgery
Conservative treatment of an ACL injury could be the best choice for more sedentary patients or where for example the ACL is not fully torn and therefore still has some good functionality and could return to it’s previous level of function with good rehabilitation. Knee stability can be improved not only by surgery but also by neuromuscular rehabilitation. Very often conservative knee rehabilitation on it’s own can provide some people with enough neuro muscular strength and control which can mean that surgery is not indicated initially. It is often believed that surgery is the only option to return to sport for example but that is simply not the case. In the cases where conservative management is deemed the best approach, the physiotherapist will provide a plan to initially re-gain of full ROM, a plan to reinforce and restore proprioception and a normal gait pattern as well as as a lower limb strength an mobility programme. However, if symptomatic instability of the knee is not reduced after a intensive course of physiotherapy nor after adjustment of activity an anterior cruciate ligament reconstruction may be indicated.
When considering surgery, the patient’s age, sporting activities and foremost subjective instability symptoms in daily life activities should be taken into full consideration.
It is useful to remember that injuries to the ACL rarely occur in isolation. The presence and extent of other injuries may affect the way in which the ACL injury is managed. Indeed the mechanism of injury can also damage the Medial Collateral Ligament (MCL) or the meniscus ( known as the unhappy triad). Other associated injuries could be microfractures or bone contusions, both with or without chondral injuries that may also need consideration.
Return to sport testing
Before you return to your sport we at Movement Perfected would test the injured knee to ensure it has the required stability to return to sport as safely as possible.
These tests include:
1 REP MAX
The one-repetition maximum strength test (1RM), used to measure dynamic knee extension strength executed in an extensor chair,
single leg hop
In this test, the aim is to jump as far as possible on a single leg, without losing balance and landing firmly. The distance is measured from the start line to the heel of the landing leg. The goal is to have a less than 10% difference in hop distance between the injured limb and uninjured limb
6 meter timed hop
In the 6 meter timed hop test, the aim is to jump as fast as possible on a single leg over a distance of 6 meters, without losing balance and landing firmly. The goal is to have a less than 10% time difference in the time taken to hop through between the injured limb and uninjured limb.
How to rehabilitate an ACL safely and effectively and a timeline of recovery
Often people are advised that surgery is the only option when you have an ACL tear, but were they also advised that after ACL surgery your risk of re- tearing your ACL is twice as high as the rest of the population? Also unfortunately, if you return to sport too early ( within a year) this can also cause you to re- tear your ACL, Similarly Osteoarthritis can develop in an ACL injured knee whether you have surgery or not- all these facts are often not full communicated to individuals and not made clear.
So why does the ACL repair take so long to heal? In simple terms, during an ACL repair part of your tendon ( either from the hamstrings or quadriceps) is taken to replace a ligament. Now the give away here is that we are expecting a tendon ( which connects muscle to bone) to act as a ligament ( a structure which connects two bones together). Through this surgery, we are expecting the tissue to totally change it’s function- therefore the two main things this requires for a successful outcome is 1) TIME and 2) GRADUAL LOADING.
It is important to note that without the graft being placed under some stress the process of the tendon becoming ligamentous in properties, known as ligamentization, would not occur.
The entire ACL rehabilitation process is unique to each person but overwhelmingly this is what physiotherapy seeks to address during the process.
- Establishing symmetrical strength and range of motion
- Progression to increased weight-bearing activitie
- A gait/run progression
- Incorporation of plyometrics
- Gradual introduction of sport specific activities
- Inclusion of reactive activities
A study by Failla et al 2016 showed significantly improved outcomes 2 years after ACL reconstruction surgery in a group who underwent pre-operative rehabilitation as compared to a group receiving similar post-operative rehabilitation only. These improved outcomes included both returning to pre-injury level of sports as well as patient-reported outcomes measures of knee function
A recent study has highlighted that very often ACL injuries are under treated post an ACL repair. An emerging realisation is evident that individuals and athletes may be overtreated with ACL surgery, but undertreated when it comes to rehabilitation. ‘Undertreated’ is defined as either not enough rehabilitative input ( length of time) or where the rehabilitation process has not been challenging enough to allow for full recovery.
This is why at Movement Perfected we follow rehabilitation protocols that follow evidence-based guidelines. This involves reccommneding to our clients more than 6 months’ rehabilitation, including agility and landing exercises and a structured return to sport. We work closely with our consultants to ensure that physiotherapy intervention starts immediately post operatively.
There is a common mis conception that it is the surgery that will get an individual back to playing sport, but this isn’t the case- surgery will fix the anatomical structural damage but it is the rehabilitation afterwards that will get you back playing or participating in your sport.
So, the rehabilitation phase is crucial to success. The rehabilitation of ACL deficient and ACL reconstructed knees should be the same. The challenge is, it seems, that some individuals with ACL deficiency do not put the same level of effort or commitment into rehabilitation as they would following a reconstruction. If an individual with an ACL deficient knee is consistently showing signs of instability, then they may need to explore surgical management to achieve their goals.
Management of all ACL injuries should involve criteria-based, not time-based, rehabilitation where the individual has to achieve certain markers before progressing onto the next stage. Historically, time-based markers determined when the patient could move onto the next phase; however, owing to variables in everyone’s ability, their level of dedication to rehabilitation, their progress will vary and may not be time dependent. However, time does need to be considered with regards to physiological healing processes, tissues repair and strength, ossification post-surgery, etc.