Keys to Early ACL Rehab


There are over 200,000 cases of ACL tears annually, with most of them repaired surgically. ACL reconstructions are a commonly performed procedure at the Foundry division of Ortho RI, with the majority of the patient population being young, active people. While the rehab process is long and intense, there are some early keys that can jump start the rehab process and improve the likelihood of returning to 100%.

1. Pain management
You do not get any bonus points for not taking pain medication. A decrease in pain will allow you to initiate strengthening and ROM exercises as early as possible. With less pain, the patient will be able to tolerate sitting in extension (more on this later) with less discomfort. Additionally, decreased pain will make sleep easier. Sleep is vital to healing, as certain hormones are released as we sleep that facilitates the healing process.

2. Decrease swelling
Swelling is going to have two main detrimental effects in early rehab; slow the progression of ROM and inhibit activation of the quadriceps muscle. With swelling in and around the joint, a sensation of “tightness” around the joint may be felt, making it increasingly uncomfortable to attempt to restore normal range of motion. Additionally, when swelling approaches the quadriceps muscle, the muscle shuts down and will not be able to contract. The job of the quadriceps muscle is to straighten the knee, and without the quadriceps muscle firing appropriately, the knee will not be stable when standing/walking. Decreasing swelling is a multi-faceted approach which includes Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), ice, compression, and elevation. Following, surgery, the leg should be propped above the level of the heart as much as possible and ice should be wrapped around the knee for 20 minutes every hour to combat both swelling and pain. If NSAIDs are prescribed for the patient, they should be taken to decrease swelling as well as pain. 

3. Extension and flexion ROM
Restoring ROM (range of motion) on an appropriate schedule will be vital in progressing through the rehabilitative process without delays. An early focus should be placed on maximizing extension of the knee. One of the biggest mistakes that a patient can make post-operatively is resting with a pillow propped under the knee so that it is bent. This positioning will make achieving normal extension, which is required for a normal gait pattern, increasingly difficult. The lack of full knee extension will compromise the ability of the quadriceps muscle to stabilize the knee, resulting in less stability in weight bearing positions such as standing, walking, and running. Full knee extension ROM can be achieved with proper positioning of the knee in extension when resting, as well as quad activation to actively straighten the knee and push further in to extension.
An early focus on knee flexion ROM is also important to begin to restore normal function of the knee and avoid a condition known as arthrofibrosis. Arthrofibrosis occurs at the knee when a lack of motion results in fibrotic adhesions. These fibrotic adhesions further restrict the motion, and may require further surgery to allow for motion to be restored. Performing assisted knee flexion exercises, such as heel slides help to restore the appropriate ROM and avoid further complications.

4. Quad activation
As mentioned previously, swelling at the knee can cause an inhibition of the quadriceps muscle. Increasing the quadriceps muscle activity will help to restore knee flexion and extension ROM at a quicker pace. Perhaps more importantly, early quadriceps exercises have shown to assist in decreasing joint laxity up to one year post-surgery. As anyone who has had an ACL reconstruction can attest, it is a laborious rehab, and the last thing that any patient would want would be increased joint laxity that can either cause further breakdown of the cartilage in the knee or a possible re-tear of the reconstructed ligament. Additionally, the earlier that the quadriceps muscle is able to contract normally and provide stability to the joint, the earlier that the patient will be eligible to discontinue use of the brace and restore normal gait mechanics. While isometric quadriceps exercises such as quad sets and straight leg raises will not add any substantial strength to the quadriceps, the neuromuscular retraining of the muscle will allow for a quicker transition to a strengthening program and a decreased risk for quadriceps atrophy. 


Shaw T, Williams M, Chipchase L. Do early quadriceps exercises affect the outcome of ACL reconstruction? A randomised controlled trial. Australian Journal of Physiotherapy. 2005;51(1). 9-17. 

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  • knee rehab