Overview
The anterior cruciate ligament (ACL) is one of four major ligaments in your knee. It connects the femur (thigh bone) to the tibia (shin bone) and controls / limits the motion between these bones. Basically the ACL prevents your tibia from going too far forward or rotating too much. In addition to being a mechanical stabilizer, it also provides input to your nervous system about joint position, also known as proprioception. Without a fully intact ACL, stability is compromised and can lead to feeling "loose", unstable and weak. In the event of a tear, surgery might be indicated depending on the severity and what level of sport / activities the person plans to return to. Conservative treatment (no surgery) can be just as effective (Frobell et al., 2010) depending on the above variables. A consultation with an orthopedic surgeon and physical therapist is recommended to decipher this. Regardless of the treatment pathway, a few goals are going to be the same.
Pre-Operative & Prehab Goals
1. First step is to REDUCE swelling and pain – This can be achieved with R.I.C.E.
–Rest: This doesn't mean just sit on the couch though!
–Ice: Approximately 15-20 minutes every couple of hours to help reduce pain. Cryocuffs are a great option, ask your physio or surgeon about these.
–Compression: Use a tensor wrap to limit how much swelling builds up but careful to not restrict too much blood flow.
–Elevation: Get gravity on your side! Gentle range of motion (ROM) exercises should be initiated to keep your knee moving and help push swelling away. Heel slides on the wall work great for this.
“Get gravity on your side!”
2. The second goal is to improve knee RANGE OF MOTION – This doubles on the previous point about gentle ROM exercises. Initially you want to prevent it from becoming too stiff. These exercises should be progressed under the supervision of a physical therapist to ensure it is safe for the knee. The goal is to have near full range of motion before surgery but this doesn't mean making it more unstable.
3. The third goal is to improve STRENGTH – The quadriceps (front of thigh) muscle is particularly important. Pre-operative quadriceps strength is the single most important predictor for knee function two years following surgery. Some researchers have even suggested postponing surgery until the quadriceps on the injured side has returned to 80% strength of the uninjured side (Eitzen et al., 2010). Depending on the surgery performed, if a hamstring graft is used, hamstring strength will be quite important too. Furthermore a physiotherapist can use a neuromuscular stimulation device to help improve your quadriceps contraction and help with the strengthening process
"Pre-operative quadriceps strength is the single most important predictor for knee function two years following surgery."
4. The final goal is to improve BALANCE – This includes joint proprioception, which is your bodies sense of where your joint is in space. This is critical for balance and single leg stance. There might be a chance this goal may not be achieved prior to surgery depending on the surgical date. However, there is some current research to suggest it can also improve post surgical outcomes (Failla et al., 2016). This is an important goal to reach to ensure the knee feels more stable and you feel confident with quick movements. Enhancing your unconscious motor response and your nervous system's ability to generate optimal muscle firing is key for stability. This is a critical step that should not be missed!
Bottom Line
Prehab exercises before surgery has been shown to improve outcomes after surgery and ability to return to sport successfully (Failla et al., 2016). Your physio can help construct an appropriate prehab program with modalities to reduce swelling / improve muscle recruitment and exercise selection for each goal targeting improved ROM, strength, and balance.
References
Eitzen, I., Moksness, H., Synder-Mackler, L., & Risberg, M. (2010) A progressive 5-week exercise therapy program leads to significant improvement in knee function early after anterior cruciate ligament injury. Journal of Orthopaedic & Sports Physical Therapy, 40(11): 705-721.
Failla, M., Logerstedt, D., Grindem, H., Axe, M., Risberg., M, Engebretsen, L., Huston, L., Spindler, K., & Synder-Mackler, L. (2016). Does extended preoperative rehabilitation influence outcomes 2 years after ACL reconstruction? A comparative effectiveness study between the MOON and Delaware-Oslo ACL cohorts. The American Journal of Sports Medicine, 44(10): 2608-2614.
Frobell, R., Ross, E., Ross, H., Ranstam, J., Lohmander, L. (2010). A randomized trial of treatment for acute anterior cruciate ligament tears. The New England Journal of Medicine, 363: 331-342.