I. Overview of ACL injury
The anterior cruciate ligament of the knee is located within the joint, starting from the posterior part of the lateral surface of the intercondylar fossa of the femur and attaching forward, distally, and inward to the anterior part of the intercondylar spine of the tibial plateau. the ACL is responsible for the anterior stability and part of the rotation and lateral stability of the knee joint, and is not palpable on the body surface, so it is difficult for the general patient to directly perceive an injury to this ligament. In China, the incidence of ACL injuries in the general population does not have exact statistics, and the incidence of ACL injuries in professional female athletes is 0.71%, compared to 0.29% in men, and 2.37 times higher in women than in men.
ACL injuries are generally seen in sports, with rugby, basketball, soccer, and skiing being particularly common. In addition to injuries caused by collisions between the knee and others, 78% of ACL injuries are non-contact, often occurring in landings, sharp stops and violent twisting movements. In soccer, shifting defense and kicking the ball while running are relatively dangerous; in basketball, side-jumping turns and single-leg landings are relatively dangerous; in skiing, the knee rotates outward when the front end of the ski is blocked, which is a typical non-contact injury mechanism of ACL. Acute injuries tend to have knee swelling, mainly due to blood accumulation in the joint, and can generally occur within minutes to 3 hours after the injury. In acute knee injuries (excluding fractures), 70% of those who present with blood in the knee have a combined ACL injury.
The incidence of ACL injuries combined with meniscal tears is around 60%, and the rate and severity of meniscal damage increases as the duration of the ACL injury increases. Sometimes a “barrel stem tear” (also called a “basket injury”) occurs in the meniscus and the torn flap is displaced below the intercondylar fossa, causing interlocking symptoms in the knee joint, with the patient complaining of a “stuck” joint The patient complains of a “stuck” joint, with joint flexibility fixed at a certain angle or with limited extension or hyperflexion. Cradle injuries are more common to the medial meniscus and less common to the lateral meniscus. With time, extension or flexion may improve, but by this time the torn meniscus flap has been compressed severely resulting in deformation and degeneration that cannot be repaired. If there is a combined lateral collateral ligament injury to the knee, swelling and pain may occur at the injured lateral collateral ligament. After ACL reconstruction, a significant number of patients have experienced effective improvement in knee function, and some athletes have returned to play and achieved world championships.
II. Basics of ACL injury: etiology and prevention, symptoms and related tests
1.Etiology and prevention
General traumatic disorders rarely talk about the cause of the disease, the reason is simple: the cause is trauma! However, the concept of sports medicine should not only focus on the treatment of ACL injury, but also on the prevention of the injury. Until biological techniques, material techniques and clinical surgery are perfectly integrated, reconstructed ligaments will not be as natural as they could be! Therefore, one of our most important tasks is to try to start with the mechanism of injury. Because it makes far more sense to give an athlete a normal ACL than to reconstruct one for him!
First, let’s look at the mechanism of non-contact injury of the ACL: A, normal motion of the knee. b, bending the knee about 23 ° (generally less than 30 °) single-leg weight bearing, the knee joint valgus, increased pressure on the lateral compartment, medial collateral ligament tension. c, quadriceps muscle force, tibia forward, femoral epicondyle relative to the lateral tibial plateau posterior shift (generally also think that body weight combined with torsional violence makes the femur relative to the The ACL is fractured by this force (usually within 40 ms of the injury). (The posterior edge of the femoral condyle and tibial plateau is seen on the NMR in some patients with ACL injuries.)
2, clinical symptoms
Clinical symptoms are divided into three categories.
(1) The exclusive injury symptoms of ACL, which are described in detail below.
(2) Combined meniscal, cartilage, or other ligament injuries can be characterized by knee pain, popping, interlocking, or specific manifestations of the corresponding ligaments.
(3) abnormal state of the knee joint, most patients may have atrophy of the muscles around the knee joint, especially the quadriceps muscle atrophy.
The acute phase of ACL injury is characterized by knee pain, knee swelling, limited knee extension, knee instability, and limited knee mobility.
Clinical examination.
(1) Physical examination, also called physical examination. There are generally three techniques: 90° anterior drawer test with knee flexion; Lachman test; and axial shift test.
(2) X-ray examination
(3) Magnetic resonance imaging.
The purpose of MRI examination is to.
Confirm the diagnosis of ACL injury and provide diagnostic evidence for surgical treatment. Some old ACL injuries, because their upper stops are adherent to the lateral wall of the intercondylar fossa and other parts, sometimes give the doctor a false impression on examination and are easily misdiagnosed as unbroken or partially broken, MRI examination helps to clarify this situation. Clarifying the presence of damage to other knee structures such as articular cartilage and meniscus allows for adequate preparation prior to surgery. It is important to note that different levels of MRI have different imaging results, different levels of imaging by different shooters, and different levels of radiologists read the films with different results, so it is recommended that patients provide an MRI directly instead of a report when visiting an outpatient clinic or during an online consultation.
The main treatment methods for ACL injury
ACL rupture usually requires surgical treatment, i.e. arthroscopic ACL reconstruction. The current mainstream technique is still to perform arthroscopic ACL reconstruction using autologous N cord tendon as a graft. Reconstruction of the ACL involves drilling channels in the tibia and femur and then grafting the tendon into the joint cavity and into the channels at both ends to replace the ACL, with the tendon being fixed at both ends of the channels with internal fixation devices. This fixation device is used according to the needs of the procedure and is usually a combination of absorbable and metal nails. Whether the internal fixation should be removed or not depends on the foreign body reaction at the site of internal fixation, and there is no pain at the site of internal fixation after surgery, etc. It can be removed without surgery again. Patients usually rest for 3-4 weeks after surgery and can return to office work according to the doctor’s recommendation. Patients who have a smooth rehabilitation procedure can walk on crutches within 1 month after surgery, and after 3 months they can walk normally with the splint removed, and learn to jog in 4-5 months, and can do general sports and fast running in 6 months after surgery according to the muscle strength recovery, and confrontational sports in 10-12 months after surgery.
Some patients will be concerned about the difference between the clinical effect of single and double bundle, which is still controversial in clinical practice. Those who originally insisted on single bundle are still insisting on it, and those who originally advocated double bundle are now divided into two categories: one category is still diligently pursuing it, and one category returns to single bundle technique. However, the real anatomical reconstruction should be developed in the direction of biology, and the bottleneck of graft and graft-bone healing still needs to be broken.
IV. Indications and timing of ACL reconstruction surgery
1. Young patients diagnosed with ACL injury should undergo ACL reconstruction surgery if any of the following conditions are present.
(1) Repeated sprains of the knee joint.
(2) Knee instability.
(3) Combined injury to the meniscus or other important stable structures of the knee.
(4) Those who have clear cartilage damage in the knee joint that needs to be repaired.
2. Patients who do not require ligament reconstruction surgery.
(1) No indication for surgery as described above and no joint instability.
(2) Patients who wear a brace or cast for conservative treatment of ligament healing in the acute phase (usually within 2 weeks after the injury) under the advice of a physician.
(3) Ligament rupture for many years, cartilage damage is very serious, according to the specific situation to take other treatment measures.
3.Timing of reconstruction surgery.
(1) Patients with simple ACL rupture can undergo surgery after the acute period, when the swelling of the joint has basically subsided and the mobility of the joint is basically normal. If surgery is temporarily not possible, the braking brace should be removed after the acute period, and normal walking should be resumed, and muscle strength should be practiced diligently to prevent muscle atrophy.
(2) In case of combined sutureable meniscus injury or cartilage injury requiring repair (as judged by the doctor), surgery should be performed as soon as possible after the acute period in order to get a chance to repair the meniscus or cartilage, preferably not longer than 3 months.
(3) In the second point, if there are symptoms of syndesmosis, aim to operate within 3 weeks to prevent difficulties in functional exercise of the joint after surgery.
(4) Combined with medial and lateral collateral ligament injuries that require sutures, it is best to operate within 2 weeks. After the acute period, the above ligaments are basically impossible to be sutured, and additional reconstruction is less effective than suturing, and more traumatic and costly.
V. Special cases of ACL injury
1.Cases that may be treated conservatively
It is worth noting that a fairly small number of patients have no clinical symptoms of instability after ACL rupture due to various factors such as muscle compensation. When clinicians face such patients, they must choose ACL reconstruction surgery carefully. The affected knee is also protected by splinting during conservative treatment and no secondary injury occurs.
2. Juvenile ACL reconstruction
In some adolescents, the epiphysis is not closed, and drilling a bone channel through the epiphyseal plate during surgery may theoretically affect bone growth. However, if an adolescent ACL rupture is not operated on and then operated on when the growth period is complete, degeneration of the knee will inevitably occur and will also lead to complications such as meniscal tears, and the longer the wait, the more serious such complications will be.
3. “Patients without symptoms”
Some patients with atypical symptoms of knee instability, i.e. grade 2-3 in instability grading, may have no symptoms when walking, going up and down stairs or even jogging in general, plus no obvious pain in the knee, and think they have no need for treatment. In fact, this is not true.
VI. Issues related to reconstructive surgery
1.Pre-operative preparation
For acute ACL injury, if swelling is present, the injured knee and the proximal and distal areas of about 10 cm should be pressure bandaged with thick cotton pads; in some patients with significant swelling, the doctor should decide whether to puncture and draw out some of the accumulated blood before applying pressure bandages. After 3-4 days of rest, functional exercises should be actively performed. One should try to practice knee extension and knee flexion to normal before surgery; otherwise, it will be relatively difficult to practice knee mobility after surgery. While waiting for the surgical bed after the diagnosis of ACL rupture, in addition to functional exercises and muscle strength exercises, it is necessary to protect the knee joint (wearing a splint during the acute phase and a knee brace after the acute phase) and avoid prolonged walking and sports to avoid secondary injuries due to knee instability. In addition, it is important to avoid infectious diseases such as colds and diarrhea, and to protect the skin of the knee joint from insect bites and scratches.
2. Risks of ACL surgery
Risk of postoperative infection. The incidence is 0.14-1.70% as reported in foreign literature. It is recommended that patients must pay attention to preoperative and postoperative hygiene, quit smoking and drinking, avoid colds and gastrointestinal infections, and avoid mosquito bites. Patients who are usually in poor health or have chronic infections must communicate with their doctors before surgery to obtain effective advice and countermeasures in a timely manner, and should not wait until they are notified of their hospitalization because of the difficulty of getting a bed and hide their condition, putting themselves at risk of postoperative infection! Joint ankylosis and adhesions are usually caused by untimely and incorrect post-operative rehabilitation. You should start compression exercises on the first day after ACL reconstruction, and joint flexion and extension exercises on the fourth to seventh day after surgery, and seek medical advice if you have difficulty in extension and flexion. In addition, it is important to prevent serious complications: if you keep sitting and lying down after the injury, serious deep vein tethering may occur, leading to life-threatening conditions.
3.Cautions for post-operative rehabilitation of ACL
(1) Common postoperative symptoms: posterior pain; elevated body temperature; joint swelling; internal ankle bruising; skin numbness; unfavorable walking.
(2) Common problems and precautions during rehabilitation.
Brace Wearing
ACL postoperative brace is commonly known as “bending splint”. The splint should be worn 24 hours a day for the first month, removed at night for the second month, and worn when walking in the third month. Some patients with good knee muscle strength should have their splints ended early at the doctor’s discretion. The main purpose of the splint is to maintain the stability of the knee joint and to protect the reconstructed ligaments from accidental injury; however, the trade-off between excessive protection and atrophy of the knee muscles should be discussed with the physician.
A common problem with braces is “dropping”. The solution comes from the patient: wrap a folded towel around the top of the inner ankle for one week, then wrap the bottom Velcro around the towel and tighten the Velcro from the bottom up.
Knee flexion exercises
The pain associated with knee flexion varies from person to person. Some patients who are sensitive to changes in joint capsule tension may experience posterior lateral knee pain, followed by medial knee pain, due to mild external rotation of the tibia for a short period of time after ACL reconstruction and fixation. Patients who have also undergone surgery to repair other stable structures of the knee, such as meniscal sutures and medial collateral ligaments, will have some difficulty flexing the knee, with slightly more pain, and will need to have perseverance. It is important to note that the knee flexion exercises should not be performed too quickly from extension to the established knee flexion angle, and are generally performed for 10-20 minutes, and when you reach the established angle, stay for 3-5 minutes, and you can start icing while staying. After straightening, you can knead the upper, inner and outer knee muscles with your hands to sense their stiffness and compare it with the opposite side, and if there is stiffness, you can massage it yourself to relax it. Some patients do not fit into the one-day practice, so the doctor can take a knee flexion every two days or even every three days, depending on the situation. In general, if excessive knee flexion causes severe swelling or stiffness of the knee muscles and joint capsule, violent massage must be avoided and it is best to rest for 2-3 days and seek medical attention.
Learn to apply ice
Ice is closely related to the process of knee flexion. Ice should be applied during and after knee flexion.
Prepare an ice bag: a large plastic bag from the supermarket, filled with 600ml-800ml of water, with ice cubes, the ratio of ice to water is about 1:1. The amount of the above ice and water mixture can be adjusted according to the size of the knee joint. Tighten the bag and try to exclude the air inside the pocket, so that the ice bag is easy to fit. Ice areas: anterior inferior knee fat pad area, medial and lateral. Painful areas during knee flexion exercises must be incorporated into the ice pack. Note: Use a towel to separate the ice pack from the skin; for patients shortly after surgery, the wound is covered with a dressing, so the dressing must be partially removed when applying ice and 1-2 layers of gauze (instead of the aforementioned “towel”) can be kept, and a layer of plastic wrap can be placed between the gauze and the ice pack for waterproofing; each ice pack lasts about 20 minutes, and the first ice pack may The first icing may last 25-30 minutes, so that the whole joint feels “cool” inside; the icy skin pain lasts for 5 minutes to stop icing to prevent frostbite; 40-60 minutes between icing, 3-6 times after a knee bending exercise; adjust the number of icing according to the degree of knee swelling the next day, and gradually master to adapt to their own The number of ice packs should be adjusted according to the degree of swelling of the knee the next day, and gradually get used to your own number of ice packs.
Squatting exercises
Squatting not only can practice the muscle strength around the knee joint, the correct squatting posture for a long time on the lumbar spine, cervical spine, etc. are beneficial. The correct static squatting posture rehabilitation program has, here is to emphasize is: static squatting before the general to experience a period of straight leg exercises, pay attention to increase the time and load of straight leg lifts (weight on the calf), the authors recommend straight leg lifts will be affected knee muscle strength to 70-80% of normal before squatting exercises. In general, when squatting quietly, initially the back can lean on the wall, so that the wall shares part of the weight. The angle of knee flexion should not be too large, except for a few patients with strong muscle strength, the knee should not be flexed more than 30° at first. After more than 30°, the body should also leave the wall, the trunk leaning forward 30-40°, the front of the knee joint but the tip of the foot, so that the strength of the N cord muscle can give full play to the reconstruction of the anterior cruciate ligament is basically not under tension. When squatting, in addition to the knee muscles tension, the rest of the body must be relaxed. After the exercise, pain in the front and medial knee muscles is a valid evidence of correct posture. Please note that increased pain within the knee joint after a static squat is an abnormal manifestation that can cause damage to the knee joint and aggravate patellofemoral joint cartilage lesions. Where this occurs, attention should be paid to changing the way: first, the affected knee muscle strength is not improved enough, to strengthen the straight leg lift exercise. Second, the pursuit of large angles at the beginning of the static squat, muscle strength can not reach, patellofemoral joint pressure, so to start practicing from a small angle. The squatting time must be improved in sections, not stagnant, so that muscle strength will grow smoothly. When practicing, you can use various entertainment methods to transfer fatigue, such as watching TV, movies, listening to music, listening to audiobooks and so on.
Intra-articular ringing
Some patients may notice a rattling sound in the knee joint during rehabilitation exercises, some of which are small and can only be felt, while others have a large, definite popping sound. There are many causes of rattling. Meniscectomy, scarring of the fat pad area, and muscle atrophy are all common causes of popping after ACL reconstruction. These, can be corrected by muscle strength exercises and adaptation training of joint activities. Most patients find the popping sound about 1 month after surgery, and it can gradually disappear about 6 months after surgery. When a popping sound is detected, it is important to communicate with the surgeon to accurately describe the location and frequency of the popping sound and the presence or absence of pain; secondly, it is important to approach the popping angle slowly when moving the knee, avoiding rapid stimulation and avoiding it if possible, and never repeatedly trying to see if the popping sound still exists. In a small percentage of patients, the intra-articular scar is not easily softened. If the rattling still occurs 2 years after surgery and affects normal joint activity, it is recommended that a second arthroscopic excision of the scar be considered in consultation with the surgeon.
It is important to note that patellofemoral cartilage damage is a pathologic clinical condition that causes knee popping. This can be reviewed in the operative record and is usually associated with pain, soreness and swelling in the anterior knee area, especially when walking up and down stairs. Patients with these clinical manifestations must communicate frequently with their physicians to obtain timely advice on the treatment of chondromalacia patellae.
Muscle contracture
About 6 weeks after surgery, a few patients may hear a ringing sound at the back of the thigh during active knee flexion, followed by a “mass” or “depression” in the area. This is due to the lack of distal tendon counteracting the active contraction of the muscle after the tendon of the semitendinosus has been removed, the lack of strong adhesions between the semitendinosus itself and the surrounding muscles and other structures, or the relative strength of the muscle itself. It is recommended that patients begin strength exercises for the N-tendon muscle 8 weeks after surgery.