Ligaments are found throughout the entire body and function as anchors connecting bone to bone. They resist specific movements in order to stabilize joints, locally. In the instance of ligament ruptures, sprains, or tears, the healing process is made difficult due to lack of blood vessels and blood supply. The ligament fibers are, usually, so dense that getting blood to the area is very difficult. With decreased blood to the area, the inflammatory response and the healing chemicals that accompany inflammation are limited. This results in a much slower healing rate and, in instances of full tears, no regeneration of the tissue.1 The anterior cruciate ligament (ACL) is one of these ligaments and, due to impact on sport and function, is very clinically significant.
The ACL is located in the knee joint and attaches the back side of the femur to the front aspect of the tibia. Due to the orientation of this ligament, it prevents forward movement of the tibia on the femur as well as rotation of the tibia on the femur. Injury to the ACL usually occurs in sports that require fast deceleration and cutting movements. Women’s soccer and Men’s football have the highest rate of ACL injury due to the quick cutting movements as well as a higher risk for player to player contact at the lower extremities.2
Injury to the ACL can be very painful and may require surgery. But when, exactly, is surgery most appropriate? Can I get by without surgery at all?
The short answer is “it depends.” There are two general approaches to ACL sprains and tears: conservative (non-surgery) and operative (surgery). Which route you decide should be based on how long you want to recover and what you will be returning to.
Conservative Treatment
Conservative treatment includes any non-surgical method of returning the knee back to normal or near-normal function. The purpose is not to necessarily heal the ligament- while that would be great, it is unlikely that would occur due to the decreased blood supply. Instead, conservative approaches such as physical therapy aim to improve stability of the knee by strengthening the muscles that surround the knee. This “dynamic stabilization” of the knee can be performed using several tools including range of motion exercises, strengthening exercises, balance interventions, or electric stimulation. This process is gradual and requires participation of the patient to maintain a home exercise program at home. However, with time, stability of the knee joint can return to near-normal levels.
Patients who will benefit the most from this approach are individuals with partial ruptures or sprains. These levels of injury maintain some ACL integrity and respond well to a conservative approach. It is possible for a complete ACL tear to be treated, but the goals of the patient play a large role in their appropriateness for physical therapy. If they are an athlete who wants to return to a high level of play with full functionality and confidence in their knee, conservative measures may not be enough to provide them the desired results. However, if the goal is to return to weekend hiking and biking, conservative measures may be enough to get you there.3
Operative Treatments
If conservative measures fail or if you are an athlete who is returning to a high demand sport, an operative approach may be more appropriate to meet expectations. Additionally, surgery may be more appropriate if there are multiple structures (other ligaments, bone or meniscus) involved. The purpose of a surgical approach is to open the knee and manually reattach the ACL to the femur and tibia or by using some ACL alternative. If the original ACL is not a viable option, the surgeon may use a portion of the patient’s hamstring or quadriceps tendon (autograph) or an ACL from a cadaver (allograph).4 Before surgery is performed, physical therapy is recommended to pre-habilitate the knee which can optimize surgical outcomes. The emphasis on pre-hab is restoring range of motion and strengthening the muscles surrounding the joint. This can last several weeks before surgery.3 The operation itself is an outpatient surgery and will return you home after completed. The weeks and months following the surgery can be a challenge and require diligent management of the knee and include physical therapy. Post-operative protocol varies depending on clinic, insurance and surgeon, but listed below is a general outline of what one can expect after an ACL reconstruction:
- Phase 1: 0-2 weeks: Use of brace and crutches. Focus on healing and gentle range of motion.
- Phase 2: 3-5 weeks: Range of motion, strengthening, balance
- Phase 3: 6-8 weeks: Take brace off. Moderate cardio training in addition to range of motion and strengthening.
- Phase 4: 9-12 weeks: Plyometrics
- Phase 5: 3-5 months: Return to running program; Interval and submaximal
- Phase 6: 6+ months: Unrestricted return to sport4
This generic look at the expected recovery time after ACL reconstruction does not address any concomitant injuries that may have also occurred and cannot be used to represent a comprehensive post-op protocol. Very rarely do individuals recover from and return to sport within 6 months with some patients needing up to 2 years for a full recovery.6
Summary
It is important to understand what to expect before deciding on a conservative or surgical approach to ACL recovery. Understand that conservative measures will not restore ACL integrity but can be an excellent way of retuning a patient to less competitive levels of sports in a timely manner. Surgical treatment can return a patient to a much higher level of play but will require significantly more time. Ultimately, choosing between conservative management of an ACL sprain and surgical repair of the ACL is a decision to be made by the patient and should be made with considerations to their goals.
References
1)Yang G, Rothrauff BB, Tuan RS. Tendon and ligament regeneration and repair: clinical relevance and developmental paradigm. Birth Defects Res C Embryo Today. 2013;99(3):203-222. doi:10.1002/bdrc.21041
2)Theisen D, Rada I, Brau A, Gette P, Seil R. Muscle Activity Onset Prior to Landing in Patients after Anterior Cruciate Ligament Injury: A Systematic Review and Meta-Analysis. PLoS One. 2016;11(5):e0155277. Published 2016 May 11. doi:10.1371/journal.pone.0155277
3)Krause M, Freudenthaler F, Frosch KH, Achtnich A, Petersen W, Akoto R. Operative Versus Conservative Treatment of Anterior Cruciate Ligament Rupture. Dtsch Arztebl Int. 2018;115(51-52):855-862. doi:10.3238/arztebl.2018.0855
4)Rehabilitation protocol for anterior cruciate ligament (n.d.). Retrieved April 18, 2022, from https://www.massgeneral.org/assets/MGH/pdf/orthopaedics/sports-medicine/physical-therapy/rehabilitation-protocol-for-ACL.pdf
5)Filbay SR, Grindem H. Evidence-based recommendations for the management of anterior cruciate ligament (ACL) rupture. Best Pract Res Clin Rheumatol. 2019;33(1):33-47. doi:10.1016/j.berh.2019.01.018