There are many factors that contribute to how a person will recover after ACL surgery. The 4 major factors for recovery are listed below. The first 2 are things you can control or work on to improve your recovery. The last 2 are factors that you do not have control over.
1. Ability to bend the knee fully before surgery
A study that looked at factors affecting recovery after ACL surgery found that people who were able to bend their knee all the way before surgery had faster recoveries than those who could not bend their knee all the way.1 Fortunately, physiotherapy treatment can help improve your ability to bend your knee before and after surgery. Our app Curovate can also help your ability to bend your knee.
2. Strength of muscles around the knee
The strength of the muscles that move the knee can predict how long it will take to recover. The faster the injured knee regains strength equal to the unaffected knee after surgery, the better the outcome is 1 year later.2 It is especially important to regain strength in the hamstring muscles (at the back of the thigh that help bend the knee). Weak hamstring muscles increases the risk of re-injuring the ACL.3 The exercises in our app Curovate can help you regain your strength.
You may have heard before that young people heal much faster than older people. This happens to be the case when it comes to ACL surgery and getting back to all of your activities. Surgery is sometimes avoided in older people because of a higher complication rate compared to younger people.4 A study on 104 patients that underwent ACL surgery found that 12 months after ACL surgery, patients who were 20 years old or younger needed less rehabilitation time than patients over 20 years old. The younger patients had less pain, less swelling, better mobility, and strength and returned back to their normal level faster.5
4. Other injured structures in the knee
There are 4 major ligaments that stabilize the knee: ACL, PCL, MCL, and LCL. The ACL can be injured alone but in more severe injuries, other structures can be torn as well. One study showed the patients who had torn multiple ligaments had a longer recovery time compared to just tearing their ACL alone.5 This is because multiple ligament injuries might require more procedures, have more pain and symptoms, and also require more time before the patient can move after surgery.5
Other common factors that have been studied with regards to how a person will recover from ACL surgery include gender, body mass index (BMI - a ratio of height to weight), and type of ACL graft used. These factors do not have a strong influence on the rate of recovery.6
Scherer, J. E., Moen, M. H., Weir, A., Schmikli, S. L., Tamminga, R., van der Hoeven, H. (2016). Factors associated with a more rapid recovery after anterior cruciate ligament reconstruction using multivariate analysis. Knee 23, 121-126. ↩
Villa, F. D., Ricci, M., Perdisa, F., Filardo, G., Gamberini, J., Caminati, D., & Villa, S. D. (2015). Anterior cruciate ligament reconstruction and rehabilitation: predictors of functional outcome. Joints 3, 179-185. ↩
Legnani C, Terzaghi C, Borgo E, Ventura A. Management of anterior cruciate ligament rupture in patients aged 40 years and older. Journal of Orthopaedics and Traumatology : Official Journal of the Italian Society of Orthopaedics and Traumatology. 2011;12(4):177-184. ↩
Anderson MJ, Browning WM, Urband CE, Kluczynski MA, Bisson LJ. A Systematic Summary of Systematic Reviews on the Topic of the Anterior Cruciate Ligament. Orthopaedic Journal of Sports Medicine. 2016;4(3). ↩