Anterior cruciate ligament (ACL) injury
Anatomy
Mechanism of injury
An anterior cruciate ligament (ACL) rupture typically occurs during sports activities or trauma. The prognosis differs depending on whether the trauma is high- or low-velocity. In a sports context, it most often involves a sudden movement with the knee dislocating, combining flexion, valgus (knee buckling), and internal rotation. This phenomenon is often described as a "medial collapse" of the knee.
This mechanism results in a dislocation of the tibia anterior to the femur, which tears the ACL and can also damage the menisci or cause concomitant bone lesions. Predisposing factors, such as a particular anatomy or specific biomechanics like Functional Hallux Limitus, can sometimes promote this type of sudden twisting by inducing abnormal translation at the end of the stance phase.
Diagnosis
Precise identification of the injury relies on a set of concordant indicators. Symptoms manifest as a high degree of suspicion in the case of significant effusion (rapid swelling of the knee due to intra-articular bleeding), the perception of an audible cracking sound at the time of the accident, and an immediate sensation of instability with dislocation of the joint.
The clinical diagnosis is then confirmed by the specialist during the physical examination. He performs reliable specific tests, such as the Lachman test or the "pivot shift," which demonstrate subluxation of the joint and abnormal laxity in the absence of a functional ACL.
Important note: The presence of blood in the joint (hemarthrosis) after a knee sprain is synonymous with anterior cruciate ligament tear in more than 70% of cases.
Finally, radiological diagnosis with MRI (Magnetic Resonance Imaging) is a useful and almost systematic examination to confirm the clinical diagnosis. Imaging is particularly useful for establishing a complete assessment by showing associated lesions, especially in the menisci, cartilage, or other ligaments, which is crucial for surgical planning.
Medical and sports context
Managing an ACL injury involves more than just analyzing the MRI image; it must be integrated into the patient's life. An assessment of individual functional abilities is conducted using a standardized questionnaire, a mobility and stability evaluation, and consideration of any pre-existing conditions or sequelae from previous injuries. The type of sports practiced, the level of intensity, and the patient's expectations also guide the treatment strategy.
Active knee control
The success of the surgical procedure is prepared well before entering the operating room. Before knee surgery, it is essential to have regained a normal, controlled gait, even if a slight extension deficit persists. Operating on a stiff or inflamed knee increases the risk of postoperative complications, particularly stiffness (arthrofibrosis).
The procedure involves reconstructing the ligament, not repairing it; therefore, it is an elective procedure that should not be rushed, unless serious meniscal or bone damage absolutely requires it. A preoperative physiotherapy phase is often prescribed to strengthen the muscles and promote drainage of the knee.
Inflammation and pain
Managing the acute phase is crucial. In cases of significant effusion, aspiration may be necessary to relieve pain and alleviate muscle stiffness. Draining the hematoma reduces intra-articular pressure and facilitates the recovery of mobility.
Furthermore, in cases of associated medial collateral ligament injury, it is necessary to wait until the pain subsides sufficiently before surgery to avoid disrupting rehabilitation. The knee should be as "calm" as possible before surgery to optimize results.
Why is surgery necessary?
The decision to operate is based on the need to restore knee mechanics. The ACL is a key element in the rotational stability of the knee. In the event of an injury, a feeling of insecurity may be experienced, such as a sensation of instability during certain movements, particularly during pivots or changes of direction.
The anterior cruciate ligament (ACL) must then be reconstructed to alleviate this apprehension and restore confidence in the knee. Beyond immediate comfort, the procedure has a preventative purpose: in cases of associated meniscal tears, ACL reconstruction is necessary to ensure the healing of these structures after repair and to prevent early osteoarthritis.
Rebuild the ligament
ACL surgery has benefited from numerous technical advancements. The principle of surgical ACL reconstruction involves rebuilding the anterior cruciate ligament with a tendon graft (autograft or allograft) that faithfully reproduces the tension and natural position of the anterior cruciate ligament. The torn ligament is not simply stitched, as it would not heal properly; it is replaced.
The procedure is performed under arthroscopic guidance to ensure precise placement of the new ligament. The surgeon typically harvests a tendon from the thigh (often the semitendinosus), prepares it to create a strong graft, and then fixes it within bone tunnels created in the femur and tibia. Fixation is achieved using specific devices (screws, buttons, or absorbable nails) that maintain tension during the bone integration phase.
Treating meniscal tears
Complete the stabilization
Every knee is unique, and surgery sometimes needs to be adapted to specific constraints. Certain additional procedures may be performed, such as supplementary extra-articular plasty (reinforcement on the outer side of the knee to control rotation), a realignment osteotomy in cases of significant malalignment, or remote correction of a dysfunction such as functional hallux limitus. Each situation must be assessed individually to provide the most lasting stability possible.
Safety and anesthesia: The procedure is performed under strict aseptic conditions (laminar flow). Anesthesia, whether general or regional, is discussed beforehand to ensure optimal comfort and effective pain management upon waking.
Phase 1: From the operation to the end of the 2nd week
The initial goal is to control inflammation and restore muscle function. The priority is walking without a limp using two crutches for partial weight-bearing (approximately 30 kg) to protect the initial healing while stimulating the bone. Mobility is gradually improved with active flexion according to pain tolerance and, above all, the goal of achieving full active extension of the knee, which is fundamental for future walking.
During this period, rehabilitation exercises focus on gait training and the transition between forward and backward steps to re-establish a correct movement pattern. Quadriceps activation and hamstring strengthening are initiated through simple exercises such as knee extensions (lifting the heel with a foam roller under the knee) or seated knee flexion. Mini-squats and toe raises on a stair step complete this initial stage.
Phase 1 (continued): Weeks 3 and 4
Progress towards independence continues. The goal is to achieve a full-weight-bearing, limp-free gait, still assisted by crutches if necessary to ensure proper movement. The patient must regain full active flexion and extension of the knee. Balance begins to be challenged, particularly the ability to balance on one leg.
The exercises gradually increase in intensity with controlled squats, lateral lunges, and forward lunges. Functional work includes chair stands and anterior and posterior planks to strengthen the core, essential for lower limb stability.
Phase 2 transition tests: To progress, several criteria are checked: the local condition of the knee (absence of significant edema, healthy scars), active control and mobility, as well as balance. Technological tools (video, sensors) can analyze gait and force to validate this stage.
Phase 2: Weeks 5 to 8
This is the consolidation and strengthening phase. The patient should be able to walk without a limp and without crutches. The work focuses on active control while standing on one foot and performing squats on one or two legs. It is crucial to perform exercises to rebalance the agonist and antagonist muscles, as well as strengthening and stretching the entire muscle chains (hamstrings, quadriceps, abductors, adductors). Joint mobility should be complete or nearly complete.
Typical exercises include squats and single-leg balances, forward lunges, and the single-leg "bridge" (glutes/hamstrings) using a gym ball. Functional exercises such as sitting down and standing up from a chair are now performed first on both legs and then on one leg.
Phase 3: Weeks 9 to 12
Phase 4: From the 13th to the 16th week and beyond
This phase marks the beginning of the rehabilitation process. The program includes trampoline training and a jumping school to work on impact absorption. Fast forward and backward sprints and lateral movements are reintroduced. Exercises become static-dynamic (for example, with a squat bar). The resumption of specific sporting activities is done under active supervision, with an emphasis on endurance and overall muscle rebalancing.
Return to sport (Phase 5)
Returning to sport is not a date on a calendar, but the validation of a functional state. Before resuming pivot-contact sports (starts, sudden stops, contact and changes of direction) such as badminton, squash, tennis, football, basketball, ice hockey or skiing, strict validation is necessary.
We recommend a gradual return to sport through mime exercises: this involves going back to the sidelines to repeat sequences of your sport, without contact, at progressively increasing speeds. This step helps reprogram the brain and knee-protective reflexes before facing the unpredictability of competition.
Practical information about daily life
What kind of scar will I have? Because the procedure is performed arthroscopically, the scars are minimal. Three small incisions are needed to insert the camera and instruments. An additional 3-4 cm incision, usually located on the upper part of the tibia, is required to harvest the graft. These scars fade over time.
When will I be able to take a shower? The dressings applied at the clinic are usually plasticized and waterproof, allowing you to shower as soon as you return home. However, you should avoid baths or swimming pools until the skin has completely healed (approximately 3 weeks).
How long will I need to use canes? The use of crutches is maintained until walking is fluid. Crutches must be used until full knee extension and a symmetrical, limp-free gait are achieved. The gait should be smooth and harmonious when the crutches are no longer needed. It is not recommended to begin with only one crutch; progress to walking with two crutches, then without any crutches at all.
When will I be able to drive? Resuming driving depends on the side operated on and the type of vehicle. If it is the left knee and you have an automatic car, driving is possible quickly. If it is the right knee (or left knee with a manual transmission), you should wait a certain amount of time (generally 4 to 6 weeks) until you are able to perform effective emergency braking without pain or hesitation.
How long does the sick leave last? The length of your leave depends on your profession. For sedentary office work, a return to work can be considered after 2 to 4 weeks, depending on your comfort and the amount of travel required. For physically demanding work requiring prolonged standing or lifting heavy loads, the leave may last 3 to 4 months. Your surgeon will adjust this duration based on your recovery and the specific requirements of your job.
Personalized tracking
The Medicol approach is based on a holistic view of the patient, where surgery is just one step in a complete recovery process. We place paramount importance on the objective measurement of your progress.
Personalized monitoring is implemented using clinical and functional scores. You will be asked to complete the ACL-RSI questionnaire, a scientifically validated tool that assesses your expectations, concerns, and psychological confidence in your knee. This assessment is carried out at each follow-up appointment. It allows the doctor and the healthcare team to identify your specific difficulties and adapt your rehabilitation plan in real time. The goal is to personalize your care so that you are the main participant in your recovery.
MedicolRehab Program
To support you on a daily basis between physiotherapy sessions, Medicol offers the "MedicolRehab" program.
This system gives you access to instructional videos illustrating the rehabilitation exercises described in this brochure. You will find a daily rehabilitation program designed to progress alongside your recovery phases. These visual aids help you perform the movements with the correct technique and intensity, thus ensuring the safety of your home workouts and optimizing the final outcome of the intervention.
Want to learn more about ligament injuries?
On our Medicol website you will find additional detailed information.
We work in close collaboration
We collaborate with referring physicians, external specialists recognized for their expertise in a specific area of orthopedics. These physicians work in close coordination with us to ensure the best possible care.
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