Torn ACL - should I have an operation?

Not every cruciate injury requires reconstruction. Physiotherapist Lesley Hall explains...

First published in 2008, and reviewed August 2023 by Dr Sheila Strover (Clinical Editor)

 

What next? Should you have an operation to replace the ligament?

This is a big question for which there may not be a straight-forward answer. Many people research ACL injury themselves on the Internet and become confused by contradictory advice. We will try to lay out the options with the advantages and disadvantages of each - you will see that no single course of action can be right for everyone.

Firstly, let's consider the 'rule of thirds':

• Approximately one third of people can lead an absolutely normal life, including competitive sport, without an ACL. The only way to find out if you fit into this category is to follow a conservative rehabilitation programme and see what happens - if the knee is stable at each stage, move onto the next, being sure to regain full strength and mobility before attempting any sports specific training.
• Approximately one third of people can manage every day life without an ACL but cannot increase their activities to include a reasonable level of sport. This group may be able to manage controlled exercise such as using a gym and cycling but would not be able to play tennis or football, which involve twisting and unexpected movements. Typically people in this group follow a conservative protocol but have problems as soon as they return to sport. People in this group who want to continue with sport will need surgery, however if they are at a stage in their life where they are prepared to curtail certain activities, they may manage without surgery.
• The final third of people experience instability in an ACL deficient knee during everyday activities such as stair climbing, walking on uneven ground or even turning from the sink to the cooker in the kitchen! This group need surgery.

If we all knew in advance which group we fitted into, life would be so much simpler. The only way to find out is to follow a conservative rehabilitation programme and see what happens. It is important to progress in stages and gradually increase activity levels as strength, mobility and co-ordination allow. Return to sport (depending on the sport), is likely to be at least 3-6 months. Return to sport before adequate strength is acquired is just increasing the risk of further injury.

 

The ACL-deficient knee

Secondly, let's consider the possible effects of an ACL deficient knee. There may be a number of important considerations - will surgery prevent these?:

• Instability - the knee may give way unexpectedly or it may just feel 'wobbly'.
• Recurrent injury - episodes of giving way can lead to additional trauma in the joint, other structures such as the menisci (cartilages) may become damaged.
• Increased movement may be present in the joint even though you are unaware of it. Over time this can lead to stretching of 'secondary restraints' - other structures which have become limiting factors in the absence of the ACL. Increased movement in the joint may also lead to the early onset of degenerative changes (wear and tear) in the joint surface cartilage.

 

Management Options

Thirdly, let's discuss what management options might be available to you.

Some years ago it was generally felt that reconstruction was advisable, even if the knee wasn't giving way, to avoid the development of osteoarthritic changes. It has however, not been shown that reconstruction necessarily prevents this onset. Together with the surgeon, you may decide to take one of the following routes -

• Conservative management - Once the knee has settled down from the injury, this requires an intensive rehabilitation programme to regain full movement, strength, flexibility and co-ordination. Progression should be staged to avoid further injury and sport should only be resumed when strength is equivalent to the uninjured leg and there has been no evidence of instability. You may find that you progress to a certain level and cannot move on thereby having to limit some activities in the future.
• Wait and see approach - In this case you may consider surgery in the future if necessary. A conservative protocol will be initiated but if there is any episode of instability then reconstruction occurs. The advantage of this approach is that you will not undergo surgery unnecessarily however, there is always the risk that the episode of instability that promotes surgery, may cause further damage in the joint. The disadvantage of this approach is that you may spend months in rehab only to find that you need surgery anyway, thus increasing the time from injury to full recovery. The fact is, that the higher the level of activity you want to participate in, the higher the likelihood you will eventually require surgery.
• Immediate reconstructive surgery - It is now generally accepted that even if the preferred course of action is surgery, it is advisable to wait until the acute post-injury phase has settled - usually 4-6 weeks. Post-operative recovery will be easier if the swelling in the knee has gone, if there is full movement and reasonable muscle control. Professional sportsmen and women will usually take this option primarily because they need to be back playing in the shortest possible time. They cannot afford to spend 3-4 months in rehab only to find that the knee gives way as soon as they start serious training.

Which option is right for you? You may be given conflicting advice but ideally you should understand the alternatives and be able to make your own informed choice. Unfortunately, in the real world, options may be limited by availability and accessibility of surgery.

I would like to give you some examples to illustrate the points I have made.

Example 1

A middle-aged woman, who is not particularly sporty, injures her knee on the annual family ski trip. On her return she begins a rehab programme and, after one month, is managing everyday activities with little problem. She really doesn't want to have an operation and embark on the long recovery necessary. She decides to follow a conservative approach on the understanding that if she wants to go skiing again in the future, she must prepare fully beforehand.

Example 2

A similar aged man also has a skiing injury, however, he participates in leisure football and plays squash. Although he gets back to everyday activities fairly quickly, his knee feels wobbly occasionally. He definitely wants to get back to his sporting activities so decides to opt for reconstruction.

These examples are fairly clear-cut but what about this one? -

Example 3

A twenty year old student ruptures his ACL playing university rugby. He has the opportunity of going on an expedition abroad in a couple of months time - this will not involve sport as such but will be exhaustive trekking on uneven terrain. He definitely wants to get back to rugby. He has a perfect joint apart from the ACL. His choices?

1. Forget the expedition, have surgery and be ready for next season.
2. Follow the 'wait & see' approach in the hope that he will be able to go on the expedition. The risk is that the knee may give way just prior to the expedition and he won't make it, or that it may give way when he is away in a difficult situation abroad. He may however, be able to strengthen the knee, have no sign of instability and manage the trip with no problem.
3. He needs to take into account that he has a good knee at this stage - further injury could cause more damage and compromise future success of surgery. Also, if he does the trip first, then has surgery, he will miss most of next seasons' rugby.
4. One other option, which we have not considered, is open to this young man. He could follow an intensive conservative protocol to get the leg as strong as possible before the expedition, and also use a special ACL brace to protect the knee whilst away. This should lead to a successful trip with no further injury but will not help next season! On the down side - good braces which provide adequate support often cost in excess of £400 and he will not be able to use this to play rugby in the future. Rigid braces are not permitted in contact sports.

Well, that ends Part 5. In the first five parts of this tutorial, I went over the function of the ACL, how it may become injured, the management in the first 24 hours, and the first visit to the clinician. I highlighted the point that not all ACL tears lead to surgery. As you could see, there is not always a simple answer. Each person is an individual and the decision has to be based on a variety of factors. If you decide to go ahead with surgery more information can be found about the surgical options.

In Part 6 I will discuss the general principles of ACL rehabilitation.

 

---

PREVIOUS PART: Clinical assessment of ACL tears

NEXT PART: General principles of ACL rehabilitation