Treatment for an ACL tear will vary depending upon the patient's individual needs. For example, the young athlete involved in agility sports will most likely require surgery to safely return to sports. The less active, usually older, individual may be able to return to a quieter lifestyle without surgery using physical therapy rehab.
A torn ACL will not heal without surgery. But nonsurgical treatment may be effective for patients who are elderly or have a very low activity level. If the overall stability of the knee is intact, then simple, nonsurgical options may allow a return to activity sooner.
After acute injury, initial steps should be taken to reduce swelling by applying the established RICE principles (Rest, Ice, Compression, and Elevation). Early efforts should be made to regain full ROM, especially extension, and walking with full weight bearing is encouraged 7-10 days after injury. Usually within 1-3 weeks acute swelling has reduced and full ROM is established.
Once full ROM is established, an aggressive rehabilitation program focusing on strengthening and endurance should be followed. The goal of these exercises is to change the quadriceps/hamstring strength ratio from a normal 3:2 ratio to a 1:1 ratio because the hamstring muscles help the ACL prevent forward translation of the tibia on the femur.
When strength is approximately 70% of normal, the rehabilitation program will incorporate a proprioceptive / balancing component using balance boards and other dynamic tools. The goal of this training is to increase stability in the knee joint replicating sport activities.
The last step of the rehabilitation program should assess which activities create pain, discomfort, or instability in the knee joint and actively modify the intensity, duration, or technique of these activities to avoid pain.
Patients should regain full ROM, reduce swelling, and have quadriceps control prior to surgery. Occasionally patients are involved in a preoperative therapy program and attainment of full ROM can take 2 weeks or longer. It has been speculated that full ROM prior to surgery can decrease postoperative rehabilitation time, and improve postoperative range of motion.
Surgery for ACL injury is an ACL reconstruction using a tendon graft and is typically performed using arthroscopic methods. The surgeon makes small incisions so that a pencil shaped instrument with a camera and lighting system attached can penetrate inside the knee joint and see the inside structures. The inside of the knee can be seen on a TV screen and the surgeon will perform surgery through several small incision points around the knee.
There are three common types of graft harvest sites:
- patellar tendon: this commonly includes the central third of the patellar tendon with bone blocks from the patella and tibia; perceived advantages of this graft include high strength, composition similar to the native ACL, and healing of bone to bone, which may be more reliable and robust.
- hamstring tendon: traditionally this includes harvest of the semitendinosis and gracilis tendons, although more recently techniques have been developed using only the semitendinosis in quadrupled form. Hamstring tendons offer ease of harvest and may offer less postoperative pain for the patient in the early recovery period
- quadriceps tendon: less commonly utilized than the other two grafts but gaining in popularity, quadriceps tendon comprises a thick, strong graft choice that may include a plug of patella bone or be comprised only tendon tissue.
It is important to discuss graft options with your surgeon to select the right graft for you. Some orthopedic research indicates lower re-tear rates with patellar tendon, but a majority of the highest quality research indicates no significant difference among the three graft options, with successful outcomes obtained with all graft choices.
Autograft versus Allograft
In addition to harvest site, another difference in grafts to consider is autograft versus allograft. Allografts are harvested from cadaver donors while autografts are harvested from the patient undergoing ACL reconstruction. Each graft has advantages and disadvantages. Most orthopedic research has demonstrated lower re-tear rates using autograft tissue, and this is generally recommended in young competitive athletes under age 25. However, autograft requires additional incisions and may result in more early postoperative pain. Patients may perceive slower progress decreasing pain and restoring range of motion in the early rehab phase, although autograft completes the ligamentization process more rapidly than allograft tissue. Patients choosing allograft may benefit from less pain immediately after surgery, and may feel better sooner, but the incorporation of the graft into a new ACL may take longer than autograft, and long-term re-tear rates are higher in allograft tissue. Additionally, although increasingly rare given modern testing and sterilization techniques, disease transmission of hepatitis and HIV remains possible, generally considered a 1: 1.6 million risk.
ACL Injury in Children
Incidence: ACL injuries in patients younger than 14 years vary from 3% to 10%. However, sports are becoming increasingly more competitive at younger ages, thus ACL injury incidence is expected to increase among the younger population.
Treatment: Initially, an ACL injury in children is treated non-operatively, using a similar treatment plan as described above, especially in children with widely open growth centers. With patients who fail conservative, non-operative treatment operative treatment must be considered because recurrent episodes of pivoting cause cartilage and mensical damage, which can lead to early degenerative changes.
Special considerations must be made when deciding whether or not to move forth ACL reconstructive surgery in children. There is possibility of interrupting and/or arresting normal bone growth that can result in significant leg length differences or angular deformity. Physeal-sparing (avoiding growth plate trauma) ACL reconstruction can be performed for younger patients, and improvements and technology and surgical technique have opened this option to many patients previously ineligible for surgery. Nonetheless there remain concerns these surgeries sacrifice accurate restoration of the ACL anatomy for the sake of protecting the growth plates.
New Developments in ACL Reconstruction
While ACL reconstructions have allowed patients to return to high level sports and prevent meniscus tears, the surgery still has room for improvement. Recent studies of patients that had ACL reconstructions 10 years prior still develop early osteoarthritis. There has been a lot of interest in ACL augmentation and double bundle ACL reconstruction. These are surgical techniques that are aimed to preserve or replace the normal ACL in a more anatomic fashion.
With ACL augmentation surgery, the goal is to preserve as much of the original ACL as possible while providing additional support via synthetic high-strength suture material. When the ACL is torn, the two bundles in the ACL may have varying degree of injuries. The attempt is to preserve the patient’s ACL so that it can heal together with the support of suture material, and by definition maintain the original anatomy of the ligament. Concerns with this technique include the poor healing potential of the ACL, although more recent studies suggest it may have better healing capacity than previously believed.
Nonetheless this is considered an experimental procedure at this time and may hold promise in the future.
Double Bundle ACL Reconstruction
There are two bundles to the ACL, namely the AM (anteromedial) and PL (posterolateral) bundles. Historically, only one graft is used and the anatomical position of one bundle of the ACL is reconstructed. Two or double bundle ACL reconstructions are performed to reconstruct both bundles of the ACL. This operation technically is more demanding and may be indicated for selected patients such as highly competitive professional athletes. Laboratory testing demonstrates biomechanical superiority of double bundle ACL reconstruction under some conditions, but the benefits have not been clearly observed in real patients undergoing double bundle reconstruction versus single-bundle reconstruction. At this time both surgeries are considered acceptable alternatives and single-bundle reconstruction remains the procedure of choice for the vast majority of surgeries performed in the United States.