What To Do After ACL Surgery
How to optimize early-stage rehab after ACL reconstruction (ACLR) surgery. Expert physical therapists discuss.
What to do after ACL surgery can seem confusing. Here, we discuss the strategies that we utilize with our patients to make sure they optimize their early stage ACL rehab.
To optimize early recovery after ACL reconstruction (ACLR) surgery (0-6 weeks), your main focus should be on the following:
Pain and swelling
Joint range of motion (ROM)
Knee extension
Knee flexion
Quadricep muscle activation and strength
Normalizing gait
How do I manage pain and swelling after ACL surgery?
Pain and swelling are signs of inflammation and are very common in the early stages of ACLR rehab. Inflammation often impairs joint proprioception, leading to poor muscle activation around the knee. Swelling can also mechanically limit your knee ROM. Therefore, it is very important to address pain and swelling in this early stage after surgery.
How to decrease pain and swelling:
Ice often (15-20 minutes at a time)
Compression
Elevation (prop up, knee above heart level)
Avoid unnecessary weight bearing throughout day
Active ROM exercises (heel slides, stationary cycling)
Active isotonic exercises (assisted straight leg raise, full straight leg raise, banded terminal knee extension)
Pain and swelling should also be monitored and used as guides for rehab progression.
Pain is typically measured with the Numeric Pain Rating Scale (NPRS) which is a scale from 0-10 with 0 being no pain and 10 being the worst pain imaginable. Your pain levels during activity, after activity, and the next morning should not exceed a 4/10. If pain levels exceed a 4/10, regress the activity for now until it is better tolerated.
You can measure swelling with knee circumference measurements around the knee cap. Ideally, activities should not increase swelling beyond 1 cm of knee circumference. If so, manage your load by decreasing intensity or frequency of activity.
The importance of joint range of motion after ACL surgery.
ROM exercises for knee flexion and extension should generally begin immediately after ACLR. Early joint motion is beneficial to prevent joint complications, and decrease swelling and pain.
Not adequately addressing ROM deficits in early-stage ACLR rehab can lead to poorer outcomes in later stages of rehab, with knee extension ROM being the most important.
Knee Extension After ACL Surgery
We want our patients to have full knee extension ROM by week 1! In order to walk with optimal biomechanics, we need to have sufficient knee ROM. Full knee extension is required in order to safely progress a patient off crutches.
Knee extension loss is linked to quadriceps muscle inhibition, more anterior (front) knee pain, and many joint complications if full knee extension is not met by week 3 post ACLR. If full knee extension is not attained early on after ACLR, it will be much harder to regain it later on.
Exercises for Knee Extension
Heel Prop - Low
Heel Prop - High
Quad Set
Knee Flexion After ACL Surgery
By 4–6 weeks, the goal is to have 110–120° of knee flexion ROM, which is required to begin stationary cycling and treadmill running.
Regaining knee flexion ROM should be gradual and not aggressive. Pain free range of motion is a good guide for knee ROM exercises. If there are other injuries or surgical procedures in addition to the ACL (e.g. meniscal repair), there may be more caution with progressing knee flexion ROM.
Exercises for Knee Flexion
Heel Slide
Sitting Flexion (Assisted by unaffected leg)
Bike | Seat High
Bike | Seat Low
Bike | Seat High
Bike | Seat Low
Start with half moon first
Start with seat high, then progressively lower the seat, to tolerance
Typically around week 4 - Be sure to refer to your surgeon’s protocol
Quadricep Muscle Activation and Strength after ACL Surgery
One of the most important parts of ACLR rehab is regaining knee extensor (quad) muscle strength. Deficits in quad muscle size and strength after ACLR is associated with reduced knee function, limitations in functional progression, and many complications such as altered biomechanics during gait, higher load functional tasks, decreased dynamic stability, persistent knee pain, increased risk of knee osteoarthritis (OA), and poorer return-to-sport (RTS) outcomes
Major deficits in quad strength at the end of this early stage (0-6 weeks), will make it difficult to recover strength in later stages, which influences RTS and long-term outcomes.
Quad Exercises
This exercise is initially performed with the brace on, then the brace is removed once the patient demonstrates enough quad strength, without extensor lag.
We can also utilize neuromuscular electrical stimulation (NMES) with or without blood flow restriction cuffs and/or with/without biofeedback
Quad Set with Straight Leg Raise (SLR)
Long Arc Quad
Start with a limited range of motion. The prerequisite is that you need to have at least 90 degrees of knee flexion for this to feel comfortable. Start from 90 degrees to 40 degrees of flexion, then progress towards straightening the knee all the way towards full extension.
After week 4, you can begin to straighten the knee all the way in this position.
Do not force end range extension if uncomfortable
Terminal Knee Extension (TKE)
What if I can’t get my quads to fire after ACL reconstruction surgery?
Some of our patients have difficulty firing their quads after ACL surgery. The evidence suggests we can use neuromuscular electrical stimulation (NMES) to help facilitate recruitment of the quadriceps muscles. The studies reviewed were not consistent with their treatment parameters, but it seems like using NMES for the first 4-6 weeks, 3-4x/week can help improve quad strength.
The use of biofeedback can also facilitate a better quad contraction. This allows the patient to watch the screen light up when their muscles are firing. We like to use the mTrigger at our practice. A standard protocol that we like to use is about 10-15 minutes long. We perform quad sets for 5-10 minutes, with a 10 second contraction followed by a 10 second relax period. Of course, we take breaks if the patient is getting too fatigued during that time. We like to follow that up with a few minutes of quad sets with straight leg raises, as long as the patient can maintain full extension throughout the movement (aka no extensor lag). This protocol can be found on the mTrigger protocol page.
We also utilize blood flow restriction simultaneously with these patients- you can find out more on this subject in our blog on Blood Flow Restriction Training After ACL Surgery.
Normalizing Gait After ACL Surgery
Impaired movement quality during functional tasks such as walking, jogging/running, jump-landing and sport-specific movements after ACLR are associated with an increased risk of re-injury, and early knee OA.
Not resolving movement quality during basic functional tasks such as walking at this early stage can impact movement quality during later stages of rehab and when returning to sport.
We want our patients to normalize gait early on, working on heel toe gait pattern and being comfortable loading the affected knee as tolerated. We educate our patients regarding the optimal use of crutches, teaching controlled knee extension and flexion, and hip abduction during the stance.
Below are some of the movement retraining exercises we use to normalize gait.
Movement Retraining Exercises
Terminal Knee Extension (TKE)
Heel to Toe Push Off (to normalize gait mechanics)
Single Leg Stance (to facilitate stability)
Walking over Hurdles
Be sure to use your crutches and or knee brace when performing these, and wean off of them, as guided by your physical therapist.
When can I remove crutches after ACL surgery?
We clear out patients to walk without crutches when the following are met:
Straight Leg Raise (SLR) without lag
No increased pain or swelling with weight bearing
Visible quad activation while ambulating in clinic
Use crutches as needed to normalize gait pattern and to decrease swelling.
Should I use a brace after ACL surgery?
Whether or not we should be using a brace after ACL reconstruction surgery has been debated. One 4-year prospective study found no significant differences in ligamentous laxity or radiographic images (x-rays) in the brace versus no brace groups. In fact, this study found that the no brace group had less pain when performing heavy activity or sport, compared with the brace group. A systematic review examined 12 randomized controlled trials (RCT’s) to determine if appropriate evidence exists to support bracing post ACL reconstruction. The researchers found no evidence that bracing helped for pain, range of motion, graft stability, or protection from subsequent knee injuries. With that said, it’s important to note that these studies typically include patients who have had an isolated ACL rupture with no other tissue damage to the knee (i.e. meniscus injury).
So, why do some surgeons still recommend bracing post ACL surgery? A surgeon has many jobs, but their most important job is to protect their work. The last thing a surgeon wants is for a patient to be re-injured, so they may be approaching this out of an abundance of caution. And really… we can’t blame them. It’s traumatic to injure your ACL- it can cause even more trauma to reinjure it. Sometimes having a brace on can help provide a sense of comfort and support. And in the event that your knee does give way, there is a brace there to prevent it from buckling. People also know not to get too close to you in a crowded hallway, on a subway, or on a busy street, when you're wearing a brace. This makes it less likely that somebody will bump into you.
In the event that there are additional injuries beyond an ACL injury, bracing is more desirable and is standard practice across the board. For example, if you also had a meniscus injury, a brace will be necessary. This is because too much of a knee bend can stress the meniscus and cause a re-tear. Most surgeons will limit range of motion to 90 degrees of knee bend for the first 6 weeks to allow the meniscus enough time to heal without being strained. Therefore, the brace is usually locked to the amount of knee bend available at that given time (we reassess every session), but the brace is not unlocked beyond 90 degrees until at least 6 weeks post-op. After 6 weeks, we can progressively increase the bending beyond 90 degrees, to tolerance. We also typically wean a patient off of a brace at this point as well, as long as the patient has enough quad muscle control to avoid buckling. In the event of an isolated ACL injury, without meniscus involvement, that weaning period can happen sooner (anywhere between 2-6 weeks post op, depending on the surgeon’s recommendation and patient progression).
Closing Remark on What to do After ACL Surgery
Your exact timeline and progression for rehab will depend on type of injury, whether additional tissues were injured, the type of surgery, which graft was used, etc. Your surgeon and physical therapist can best guide you on an individual basis.
There is a lot to take into consideration after ACL surgery. It’s important to work closely with your surgeon and to ask questions. They know the tissue quality better than anybody else because they’ve seen it. It’s also vital to find a physical therapist who has real experience working with patients who have had ACL injuries. This is preferably somebody who specializes in orthopedics and/or sports. They should be able to provide you with a clear roadmap to what this process looks like. Understanding that ACL rehab is a journey that takes months to complete will help to set realistic expectations and goals between you and your physical therapist.
If you are an athlete dealing with an ACL injury, and would like to work with us, contact us below to speak with a physical therapist.
Disclaimer: This is not intended to be formal medical advice. Your individual needs should be met by the appropriate health care practitioners. Please consult with a trusted provider.
Dr. Vincent Liu PT, DPT
Dr. Paul Nasri PT, DPT, OCS, COMT
Doctor of Physical Therapy
The Game Plan Physical Therapy