Current treatment and rehabilitation for ACL injuries
This essay deals with the current treatments and rehabilitation for anterior cruciate ligament (ACL) injuries including information about the causes, symptoms, and characteristics of ACL injuries. The knee joint is the largest joint in the human body, formed by three articulations between three bones consisting of the femur, patella, and tibia. The knee joints is a synovial bicondylar joint which insures motion about to 2 planes. The sagittal plane which allows flexion and extension as well as the transverse plane accommodating medial and lateral rotation. However, the medial and rotation is only possible physiologically when the knee is flexed due to the popliteus muscle. The knee joint consists of 4 ligaments, 2 intra-capsular which are the ACL and PCL and 2 extra-capsular including the MCL and LCL. The ACL is situated within the intra-capsular ligaments of the knee and is an extremely strong stabiliser of the knee. This prevents anterior displacement of the knee. The ACL is a ligament and therefore connects one bone to another. It originates from the depression in front of the intercondyloid eminence of the tibia and the fibres pass upwards, backward and laterally to insert into the lateral condyle of the femur.
Causes and aetiology
ACL injuries are one of the worlds most common types of knee injuries and occur when the forces placed upon the ligament exceeds its ability to handle those forces leading to overextension of the lower leg at the knee joint. Approximately 70% of ACL injuries occur through non-contact mechanisms. This may arise from landing incorrectly from a jump, or from twisting the lower leg and knee whilst changing direction and stopping suddenly. The remainder of cases tends to result through direct contact such as receiving a hard hit on the side of your knee and are often associated with other injuries.(1)(2)
Theses injuries would include tears to the MCL and the shock-absorbing cartilage in the knee, the meniscus. Most ACL tears tend to come about in the middle of the ligament, or when the ligament is pulled off the femoral bone.(3) Nonetheless, ACL injuries occur throughout a number of incidences and not through a single plane of motion. This is as it is the combination of anterior translation, abduction and internal rotation that likely ruptures the ACL.(4) Throughout the years with the advancement in technology aiding treatment and rehabilitation procedures, ACL injuries aren’t seen as career ending injuries compared to 50 years ago. Yet, they are still severe and takes months for recovery, since the ACL has a relatively poor blood supply. This results in a longer healing process.
Symptoms and characteristics
At the time of the injury, the patient would have felt or heard a ”pop” in the knee this as the ligament would have torn or ruptured. Once the ACL is torn or ruptured there would be sudden instability in the knee varying from the knee buckling or giving out. With instability, the knee would also have limited movement because of swelling and pain. The pain would be located on the outside and back of the knee. In addition, knee swelling would arise within the first few hours of the injury. This may be a sign of bleeding inside the joint. If swelling occurs suddenly this is usually a sign of a serious knee injury.(5) These symptoms are sudden onset and can almost be traced back to a specific incident or injury.(6)
With the ACL acting as the primary restraint to anterior tibial translation and guides the screw home mechanism associated with the knee extension. It also acts secondarily to prevent varus and valgus movements, particularly in the extended knee. As a result of an ACL injury, there would then be knock-on effects due to alteration in the mechanics of the knee. This mechanical deficit can lead to an increased risk of meniscal injury which would consequently increase the risk of osteoarthritis.(1)
When a patient with an ACL injury is initially seen for evaluation in the clinic, the doctor may order X-rays to look for any possible fractures. The doctor may also order an MRI scan to evaluate the ACL and to check for evidence of injury to other knee ligaments, meniscus cartilage, or articular cartilage.(7) Once an accurate diagnosis has been made the doctor and patient can then move forward with treatment options. Although surgery is sometimes necessary, not everyone who has an ACL injury is a candidate for surgery. As a result treating ACL injuries can either be surgical or nonsurgical. The decision to have ACL surgery depends on many factors, including the severity of the injury, patient’s age, and the patient’s activity level.(8) If surgery is chosen to be the best option, the patient will undergo ACL reconstruction. In ACL reconstruction the ligament is not repaired but instead is reconstructed usually with minimally invasive surgery using an arthroscope.(9) The surgeon will remove the torn ACL and create a new one using a graft.(8) ACL grafts can be made from patella tendons, cadaver tendons and the hamstring tendons know as gracilis and semitendinosus. The old fragments of ruptured ACL are removed and the size of the intercondylar notch where the ACL runs is assessed. The graft material is then placed in and suture material is threaded through the tunnels with the tendon graft attached and is then pulled into position and the ends are firmly fixed using various forms of fixation such as re-sorbable screws.(10) Surgery usually does not occur immediately after the injury but may be delayed three to four weeks to allow the initial swelling and bleeding to decrease. This will also allow a plan to be drawn up.(9)
Moving from the surgical aspect, partial ACL tears are usually managed conservatively by enhancing the range of motions, strengthening, and addressing proper biomechanics by an experienced physical therapist.(8) Progressive physical therapy and rehabilitation can restore the knee to a condition close to its pre-injury state and educate the patient on how to prevent instability.(7)
However, whether the treatment is surgical or not, understanding and preventing associated meniscal pathology is the key to management of this condition. Both ACL reconstruction and the nonsurgical approach aim to protect the meniscus by modifying activity levels or reconstructing the ACL whilst aiming to restore normal stability in the knee and rejuvenate the level of function prior to the injury.(11)(12)
A rehabilitation program is an essential and integral part of treatment following an ACL injury. The objective of the rehabilitation programme will be to promote muscular strength and to re-establish the knee joint functional stability. Within the programme, the rehabilitative exercises need to be compatible with normal arthrokinematics to avoid abnormal stresses on the articulating surfaces of the tibiofemoral joint and to protect other joint structures from overloading.(13) Post-operative rehabilitation starts immediately by placing the injured leg in a continuous passive motion machine. This achieves two things. Firstly, elevation, which is important to minimise swelling, and secondly early mobility which prevents stiffness. This all happens within the first 24 hours post-surgery. 24 hours after surgery weight bearing is encouraged as well as the use of crutches, however, a knee brace is not usually required as the inserted graft is sufficiently strong. Commonly, the patients are allowed to return to light sporting activities such as running 2-3 months post surgery. By 9 months the patients are introduced to Intensive muscle strengthening, proprioceptive training and start sport-specific training. From 9 months on, a careful return to competitive sport is allowed once the surgeon provides permission. The importance of a slow return is vital as the graft tendon used is removed from its blood supply before being reinserted. New blood vessels need to grow into the tendon re-establishing a blood supply and as a result, it takes 9 months to get back to full strength.(14)(15)
With ACL injuries being one of the worlds most common knee injury, treatments are becoming more modernised as well as advanced and changing a career-ending injury into a 9-month recovery process. This is because of broadening our expansion of the anatomy of the human body which helps both prior injury and its prevention as well as post ACL treatments aiding recovery. Treating ACL injuries now can either be nonsurgical, which would be conservative, or surgical, being ACL reconstruction using grafts. This all depends on the severity of the tear of the ligament as well as the patient’s activity level. Symptoms following an ACL injury are sudden onset and can be traced back to a specific incident or injury. Post-surgery rehabilitation is vital as this allows strengthening of the muscles and re-establishing the knee stability, allowing the knee to get back to how it was prior to the injury or as close as to normal possible. In addition, it educates the patient in injury prevention reducing the likelihood of following injuries.