WHAT IS AN ACL RUPTURE AND HOW DOES IT HAPPEN?
There are a pair of cruciate ligaments that form a cross in the middle of the knee as seen in the picture below. They are called the anterior and posterior cruciate ligaments.
The ACL is involved in restraining the tibia or shin bone from moving too far forward on the thigh bone as well as controlling rotational movements. It is very important for rotational stability and it contains numerous receptors (or messengers) that are very important in enabling us to detect changes in direction of movement of the knee including acceleration, speed and tension.
A tear of the ACL commonly occurs during sports that involve sudden changes of direction, jumping and landing. The most common sports I have seen ACL ruptures from include netball, skiing, football and rugby. It is usually a non-contact injury and patients will often report that they jumped and landed and felt their knee drop inwards (across the midline) as they went to change direction and they feel their knee ‘pop’ or give way under them and they fall to the floor. It can be quite painful and on attempt to stand back up the knee will often collapse under you, however, I often see plenty of rugby players and footballers who are able to continue walking and this is usually because they have very strong hamstrings that will compensate for the ACL and help support the knee.
The knee will commonly swell within a few hours, becomes quite stiff and difficult to walk on. Those that attend A+E will often receive X rays , get told they have suffered a ‘knee sprain’, that they will be better in 3-4 weeks and get sent home.
WHAT SHOULD I DO NEXT?
A rupture of the ACL renders the knee structurally unstable and thus increases the amount of movement that occurs between the tibial and femoral surfaces. The injury commonly occurs in association with damage to another ligament on the inside of the knee and/ or damage to the menisci which are moon shaped cartilage structures that act as shock absorbers within the knee joint.
You will hear this from me constantly but I do not apologise for repeating it: DIAGNOSIS IS KEY. If your X ray is clear but you have a swollen knee that you are struggling to walk on then book in to see a healthcare professional that specialises in the sporting knee injury. If you have private healthcare your insurance company may advise you to see a Physiotherapist or send you directly to an orthopaedic knee surgeon. Another option is seeing a Consultant Sports Physician ( a doctor that specialises in sports injuries and health related issues in athletes). There is no ‘right’ pathway but if an ACL rupture is suspected then anyone of these pathways should ideally result in further investigation to explore the condition of the knee. In turn this ensures that a treatment plan can be made and you will have a clearer idea of what to expect during your recovery.
Though we often hope these injuries will settle by themselves they almost never do. Invest in your health. Get the diagnosis and plan your recovery. This ensures you the fastest possible recovery.
WHAT TREATMENT SHOULD I EXPECT AND HOW LONG WILL IT TAKE?
If you have an isolated ACL tear then the doctor or healthcare professional should discuss 2 possible courses of treatment: conservative (physiotherapy) or surgical treatment. I will outline what each of these pathways involve in a different blog.
Which one to choose is always a huge debate in the medical world as despite a large amount of research on the topic there is not a superior option. It therefore comes down to the individual: what are their functional goals, do they wish to return to sport and what will the demands on the knee be, is he or she suffering from frequent knee instability/ giving way are their other health factors to consider?
You do not have to rush into this decision and any good healthcare professional will give you all the information necessary to make the best possible choice.
SHOULD I HAVE SURGERY?
- You MUST do your rehab
Irrelevant of the choice you make a good, complete rehabilitation programme is essential. A good surgeon will ensure the structure of your knee is restored but they can’t return the strength and control of your knee. As mentioned above the ACL is complied of a vast amount of receptors that give you the short sharp reactions you desire as you tackle the ski slopes or your opponent in football. This is lost when you rupture this ligament so you have to ensure that the surrounding structures are able to compensate for this loss if you are to avoid further injury. THERE IS NOT SHORT CUT. TIME PUT INTO YOUR REHABILITATION IS ESSENTIAL. It is those that avoid this that sadly fail to return to sport or go onto suffer with knee issues for years to come.
- Do you want to play sport?
If you wish to return to a sport that involves pivoting, acceleration/deceleration, jumping and landing then surgery is usually opted for. This is because we aim to give you as much support (active and passive) for the unpredictable nature of sport. One would argue that if you expose your knee to repetitive rotation as is seen during a game of football or netball then the absent ACL will increase the risk for secondary injuries such as a meniscal tear or damage to the articular surfaces of the tibia or femur.
- Is your knee unstable?
If you lead a sedentary lifestyle, have no desire to play sport but simply wish to keep active through walking, cycling and gym sessions then you would be a strong candidate for conservative management. Do bear in mind that you must also take into account the level of stability of your knee. If you are suffering frequent episodes of the knee giving way then surgery is more likely to recommended to avoid the secondary injuries that are mentioned above. A period of physiotherapy should be prescribed for 6-8 weeks to recover range of movement, strength and control and if no problems are reported and acute signs and symptoms settle then active rehabilitation can continue.
- What else did you damage?
If you ruptured your ACL in addition to suffering damage to other structures of the knee i.e. the menisci, other ligaments, bone or articular cartilage then surgical intervention will again be required to restore joint stability and ensure the optimal recovery in the short and long term. If the knee is locked due to a bucket handle tear of the meniscus then surgery will be required much earlier to regain full mobility.