Other than protecting the ACL graft, one of your primary goals after ACL reconstruction is to restore normal knee extension range of motion  (ROM).

Losing knee extension may lead to quadriceps weakness and a progression of knee arthritis. A 2021 study compared males and females ages 14-25 who underwent ACL reconstruction with a quadriceps tendon autograft. The study showed that females, higher BMI, and loss of knee extension were predictors of poorer quadriceps strength at 6 months.

Research shows that loss of knee extension can also increase the risk of re-tearing the ACL. So it's very important to improve knee extension and the strength of the quadriceps.

Why is knee extension difficult to restore after ACL surgery? Pain, muscle inhibition, fear, early immobilization, a concurrent meniscus tear, a cyclops lesion, inflammation, scar tissue, and lack of terminal knee extension stretching could all be reasons.

Frequent low, load prolonged stretching will be important to gently restore knee extension. The video above shows an example of a low-load prolonged extension stretch from the Prehab Guys - a group of Physical Therapists with a sports rehab background (exercise starts at 2:45).

Extension deficits will likely accompany weakness of the quadriceps after ACL reconstruction too. A study in 2021 examined the maximal voluntary contraction of the vastus lateralis (outer quad) and vastus medialis (inner quad) in a group of 9 people who had an ACL reconstruction. This group had a decrease in quadriceps strength compared to a group of 10 people who did not have ALC reconstruction.

The results showed that there are neurological reasons for quadriceps weakness after ACL reconstruction. A better understanding of these neurological deficits should help to improve knee extension strength.

Don't underestimate the importance of restoring knee extension range of motion after ACL reconstruction. Listen to the guidelines from your surgeon and physical therapist, but get started on low-load prolonged stretches early in your rehab to prevent contractions, quadriceps weakness, and poor outcomes.

If you have excessive swelling in your knee, then you'll want to elevate your knee above your heart to reduce swelling. If you have excessive inflammation, use diet and exercise to reduce inflammation. NSAIDs may help in the short term, but curcumin extract is shown to be as effective as NSAIDs for knee osteoarthritis.

Consider taking a high-dose curcumin extract like Active Atoms to promote a healthy inflammation response and support your ACL recovery.

For more information about the potential benefits/risk of NSAIDs and ACL reconstruction, watch this video:

References

1) Hunnicutt, J., Xerogeanes, J., Tsai, L., Sprague, P., Newsome, M., Slone, H. and Lyle, M., 2022. Terminal knee extension deficit and female sex predict poorer quadriceps strength following ACL reconstruction using all-soft tissue quadriceps tendon autografts.

2) Nuccio, S., Del Vecchio, A., Casolo, A., Labanca, L., Rocchi, J., Felici, F., Macaluso, A., Mariani, P., Falla, D., Farina, D. and Sbriccoli, P., 2022. Deficit in knee extension strength following anterior cruciate ligament reconstruction is explained by a reduced neural drive to the vasti muscles.

About Dr. Marc Robinson, PT, DPT, Cert. MDT