Physical Therapy for ACL Repair or Injury

By: Dustin Steffan, DPT

The anterior cruciate ligament (ACL) is one of many ligaments that provide structural support to the knee. The ACL specifically controls anterior movement of the tibia on the femur and is important for knee stability especially with activities requiring sprinting and quick changes in direction.

How does ACL injury occur?

ACL tears and strains occur most commonly in athletes and generally affect female athletes more than their male counterparts. It can be the result of a contact or non-contact injury. This means that injury can occur as result of trauma with another player or independently. This occurs most commonly when the foot is planted with a twisting or pivoting motion at the knee. The ACL is one of the most commonly injured ligaments in the knee, but injury rates are still relatively low.

For a deep dive into the mechanics and anatomy involved in an ACL injury we like to refer you to a blog from our partners at VASTA Performance Training and Physical Therapy in Burlington, Vermont.

What are the symptoms of an ACL injury?

Common mechanisms of injury include a twisting of the knee with the foot planted after which there will often be swelling, pain, and difficulty weight bearing. Once the initial swelling begins to reduce and more weight bearing is initiated, there can be instability of the joint with a sense of giving way. Meniscus injuries often occur at the same time as an ACL tear from which there can be pain with squatting, standing, and twisting motions.

What are the treatment options?

An ACL tear can be managed conservatively with physical therapy or operatively with an ACL repair.

An ACL repair utilizes a graft to replace the torn ligament that can be harvested from the individual or cadaver. The most common grafts used are:
• Patellar tendon graft
• Hamstring tendon graft
• Allograft (donor graft, often Achilles or tibialis anterior/posterior tendons)
Generally, these considerations are discussed with the orthopedic surgeon bearing in mind patient age, gender, and intention to return to a specific sport. The allograft is not often used in a younger population due to higher rates of re-injury.

How can Physical Therapy help?

In most cases, Physical therapy will occur prior to any planned surgical repairs to achieve full ROM, reduce joint swelling, and improve muscle strength.

Physical Therapy alone can be successful in returning to daily activities and sports not involving a great deal of sprinting or changes in direction. Some patients will opt to manage their recovery conservatively. This decision is influenced by patient age, activity level, and the degree of knee instability present. PT in this case is focused on restoring muscle strength and stability to the knee.

If an ACL repair is performed, the same initial goals stand post operatively. Depending on the orthopedic surgeon’s recommendation, patients will often wear a brace and use crutches until they are able to safely and fully activate the muscles around the knee for normal walking. This period can last from 1-6 weeks. Weight bearing strengthening is started with a focus on hip and quadriceps strength as well as balance. A return to light jogging is started, with physician clearance, around 8-12 weeks post-op with a progressive increase in jumping training to follow.

PT treatment for ACL rehabilitation may include:


• Neuro-muscular re-education: There is often an element of muscle inhibition post-operatively. Techniques to increase quadriceps and hip muscle recruitment are important to protect the knee and prevent future injury

• Stabilization: Balance and proprioceptive training exercises are prescribed with an emphasis on avoiding compromised knee positions that are often responsible for non-contact ACL injuries in the first place
• Sport Specific Training: Depending on the goals initially set, patients are provided with exercises specific to their activity level and type.

Manual Therapy

• Soft Tissue Mobilization: Scar tissue can restrict mobility and cause pain as higher level activities are resumed. Hands on treatments are utilized to restore normal mobility and facilitate the healing process.
• Joint Mobilization: Restoring joint mobility in the first 3 months post-operatively is important to avoid long-term restrictions. This is accomplished with gentle movement of the knee, ankle, and hip joints.

Return to Sport

Return to sport and higher level activity will occur after a period of 6-9 months. Research indicates that delaying return to sport towards the 9 month mark is the most beneficial. When an athlete returns to sport they should consider the level of sport to which they wish to return. Returning to sports such as soccer, basketball, and football are considered high risk with the amount of twisting, pivoting, and cutting involved. There is a documented increase in the rates of re-injury after ACL repair when patients return sports such as these. In order to minimize the risk of re-injury, it is essential to achieve symmetric muscle strength and performance with hopping and cutting drills.