Misunderstood Realities of ACL Tears: What It Feels Like, What It Looks Like, and When You Can Walk, Run, or Drive Again

1. What does an ACL tear feel like when it happens?

• First you'll probably hear and feel a pop in your knee, something that will probably make you nervous.

• You're often going to feel a noticeable sensation of instability in the knee.

• You may or may not feel burning pain right after. It could range from being not painful at all to very painful. It depends on how the person tore their ACL and also often varies from person to person.

• For many swelling can develop as quickly as within minutes to hours, that will lead to knee stiffness.

• You will likely feel warmth or heat around the injured knee especially where the swelling is.

• You'll probably have difficulty straightening the knee all the way and could also feel stiff in the surrounding muscle areas.

• You could experience a sense of wrongness or even dread when trying to walk on it.

  
  

2. What does an ACL tear look like from the outside?

It could look like this (see leg on the left), there is often swelling and redness. Haemarthrosis means bleeding into a joint, most often the knee after an injury like an ACL tear. The blood increases pressure inside the joint, leading to swelling, warmth, pain, and reduced movement.

At this link as an example of a severe multi-ligament injury including an ACL tear: https://www.reddit.com/r/KneeInjuries/comments/1n2j2co/full_knee_dislocation_resulting_in_full_tears_of/

This is a post surgical example:

https://www.reddit.com/r/KneeInjuries/comments/1gz1btx/3rd_time_testing_my_acl/

3. When can I walk after ACL Surgery?

• Early weight bearing walking is done as tolerated with support from crutches during week 1 post surgery.

• Usually during week 2 or 3 most people can walk without crutches but they're often still wearing a brace depending on if there was a meniscal repair done also and the surgeon's recommendations.

• According to the University of Delaware's ACL clinical practice guidelines many people are able to walk normally during weeks 4 to 6 post surgery without any support. This is not always the case and some people take 2-3 weeks more or 1 week less, but this is the general timeline you're looking for.

  
  

4. When can I run after ACL Surgery?

• You will get a difference answer from many sources but for our team at Pain & Performance Coach we try to make highly informed answers based on a combination of experience and the best current research. So these are the milestones we recommend that our patients reach when they can run when you reach the following milestones (this is based primarily on the Aspetar ACL clinical practice guidelines which are the most detailed research based guidelines currently available):

• Full knee extension (straightening the knee) and at least 95% of knee flexion (bending the knee) range of motion

• No swelling at all

• Limb symmetry index (LSI) of at least 80% for knee extension strength (this is measured by a dynamometer, at least something like a Tindeq progressor, but at it's very best you're using a VALD Dynamo in-line dynamometer or even a Humac Norm/Biodex isokinetic dynamometer)

• We're aiming for a knee extension torque measure (the twisting or rotational force that causes an object to rotate around an axis which tells us how strong the joint is in the position and how quickly it can generate force from that position) of at least 2.0 Nm/kg to start straight line running. If someone produces over a 2.0 Nm/kg but has less than 80% LSI for knee extension strength, we might still clear them to start working on running in a straight line depending on the other testing***

• For sprinting we tend to have patients reach a LSI of >80% eccentric impulse/deceleration phase change during countermovement jump (you need to use something called force plates for this test).

• Pain-free pool jogging and/or Alter-G treadmill running (meaning you can do it with less stress on the knee than gravity before you do it with gravity)

• Pain-free repeated single-leg hopping (example used was single leg pogos)

  
  

5. When can I drive after ACL Surgery?

• Guidelines don't generally recommend a person drives any earlier than 4 weeks after a right-sided ACL reconstruction/repair (ACLR) and at least 2 weeks after left-sided ACLR. However it can take longer for people who are slower to heal.

• Part of the key to deciding is being able to use the break properly if there's an emergency.

For more questions related to ACL surgery, injuries, and rehab, please don't hesitate to email us at team@painperformancecoach.com so we can address it in future blog posts. If you want to schedule an evaluation, don't hesitate to call us at (971)-364-0909.