Back Pain and the ACL

An all too common occurrence we see in the clinic are clients coming in with back pain after they have had ACL surgery. This is a major surgery and having back pain afterwards can really compound the discomfort you are feeling. Having back pain after surgery can also be a barrier for progress. You may not want to perform your exercises when your back hurts. The good thing is there a few potential causes for this low back discomfort and some easy steps to fix it.

Why Does my Back Hurt?

In the early stages after surgery, there are two main things we see that could contribute to low back pain. After ACL surgery, one of the most common issues we see is the inability to walk normally due to the brace. Being in an immobilizer brace alters the way you normally walk, in addition to adding more weight to that leg due to the brace. Add in the fact that you are on crutches and you’ve got some potential issues that could create back discomfort. Many people after an ACL surgery will also heavily rely on their upper body and trunk to help keep pressure off the leg which could contribute to why the back might be more sensitive.

Another potential reason we might see low back be problematic is with exercises in the early stages of the rehab process. The straight leg raise is often an exercise and also an assessment to see how well the thigh muscles work. A client is asked to squeeze the thigh and then lift the leg without the leg bending. You can either do this in the brace if you struggle with the knee bending, or you can do it outside the brace as well if you are further along. However, many times we see clients try and raise the leg and in doing so overarch their back to create momentum. This can create more sensitivity in the low back when we really don’t want it involved at all during that type of exercise.

How Do I Fix It?

Good news! There are some simple solutions you can troubleshoot with to see if it will help your low back discomfort. The first solution is to ensure that you are not taking too long of a stride when using the crutches. Doing so could create excess strain on the back and also on the unaffected leg. You also want to be compliant with your home exercise routine to get you feeling stronger in that surgical leg to get things back to normal as quickly as possible.

With regards to performing the straight leg raise exercise, an easy solution is to try doing it against a wall with your back supported instead of laying flat on your back. Also, talk with your surgeon and PT to see if you can start performing straight leg raises without the heavy immobilizer brace. This could help reduce the need to arch your back when doing them. Another tip is to get really good at quad sets, you want to feel these in your thigh and not higher up in your leg. A variation on traditional quad sets is to try doing them on your stomach like in this video.


ACL surgery is a challenge enough when dealing with just the knee. It can be even more challenging if you have low back pain after surgery. Discuss with your PT or your surgeon if you are experiencing back discomfort and address what the source of the issue might be. Do not think just because you’re dealing with back pain because of your knee surgery that it is ok to just put it off. Get it addressed as soon as you can to ensure it doesn’t hinder your ACL recovery! If you have any questions, please let us know and reach out below.