The anterior cruciate ligament (ACL) is a main stabiliser of the knee. It prevents anterior translation of the tibia and stabilises the knee during pivoting activities. It is typically torn during a severe knee sprain while playing soccer, basketball, handball, tennis, badminton, or while skiing, or may also tear during a road accident.
The trauma mechanism must be understood. The typical sprain leading to ACL tear is a suddent knee rotation and often a “pop” is felt, a strong pain and a knee swelling. Icing the knee helps to decrease pain and swelling. Knee stiffness occurs in the next days and gentle knee motion (flexion/extension) is recommended. A knee brace is not mandatory but may be confortable for the first days, as crutches which will help walking, until you can see a specialist.
After a severe knee sprain (with a pop, swelling, pain and/or knee instability), consulting an emergency unit is mandatoty to rule out a fracture and be evaluated by a doctor. In case of knee laxity, an MRI is prescribed to confirm the ligament tear and to look for associated lesions as collateral ligament tear, a meniscal tear or bone bruises. Consulting a knee specialist or an orthopaedic surgeon is necessary to check the knee and plan the best treatment: conservative or surgical. This choice will depend on the severity of the knee sprain, your usual sport activities, your professional activity, your age and your symptoms.
A conservative treatment is a specific rehabilitation protocol with a sport physiotherapist and the goal is to get back the knee range of motion and train the muscles who are the dynamic knee stabilisers. A conservative treatment is adequate for sedentary patients, for patients with a spontaneously stable knee (in case of partial ACL tear for example), for patients practicing only in-line activities (cycling, swimming), and patients having a sedentary professional activity.
A surgical treatment is recommended in case of associated lesions, for example a combined ACL and meniscal tear or collateral ligament tear. It is also indicated for sportive patients who want to go back to their pivoting activities and for heavy workers (carpenters, etc). The goal of the surgical treatment is to anatomically reconstruct the ACL and to repair associated lesions. A torn ACL can never heal completely by itself or be repaired, so it has to be reconstructed by an tendon graft, replacing the torn ACL. This is done by arthroscopy, with a camera in the joint and small scars: two scars of 5mm each for the arthroscopy, one 3cm scar to harvest the graft, and two 2cm scars to drill the bone tunnels in which the graft will be fixed. The graft may be harvested from the patellar tendon (bone-tendon-bone), or from the quadriceps tendon (tendon-bone), or from the hamstrings (gracilis and semi-tendinosous tendons, so a pure tendinous graft). Allografts (from tissues banks) are never the first choice because the risk of graft failure is 4 times higher at one year follow-up. Our prefered autograft is the central third of the quadriceps tendon because the size and thickness of the graft can be adapted to each patient and its biomechanical properties are ideals. After being placed in the joint, the draft is fixed in femoral and tibial bone tunnels using absorbable interference screws. The scars are sutured with absorbable sutures or staples, depending on your skin and aesthetic preferences.
You will come early morning in the clinic, be operated during the day, and will stay 2 or 3 days in the clinic (1 or 2 nigths after surgery). Rehabilitation begins the first day surgery to walk with cruches and bend/extend the knee. Criteria to go back home are: autonomous waking/moving, no scar bleeding, manageable pain using basic pain killers (as paracetamol, ibuprofen, tramadol). Prophylactic anticoagulation is mandatory, using subcutaneous injections or per-os pills, for a variable period depending on the surgery performed.
During hospitalisation, two physiotherapy sessions a day will help you to get your autonomy back and teach you basic exercises to get the range of motion back. After returning back home, 2 to 3 physiotherapy sessions per week and everyday home exercises have to be done.
Use of cruches to walk is necessary for 4 to 6 weeks after surgery, with partial weight-bearing, according to the surgical procedure.
The goals for the first 10 post-operative days are: reducing the knee swelling by icing it (20 min every 2 hours), scars healing, quadriceps isometric contractions, full knee extension.
Full knee extension should be recovered as soon as possible, 90° of flexion after 6 weeks, and the full knee range of motion should be recovered 3 months after surgery.
Muscles tend to rapidly get atrophic, so early isometric contractions and electrostimulation help preserving the muscles and getting rid of the cruches.
The post operative rehabilitation protocol is progressive and every new phase will begin when the previous one is accomplished. The usual delays to go back to activities are :
After 6 to 7 months of rehabilitation, a dynamic evaluation is performed: the muscle strenght is evaluated on an isokinetic machine, and balance and pliometry are quantified by video analysis. This isokinetic and functional test will help you to fine-tune your rehabilitation and allow to plan the return to play.
The return to play for pivoting activities will be allowed by the surgeon according to the knee healing and the results of these tests.
The routine follow-up appointments after surgery are :
The day before surgery, an appointment with the anesthesiologist will allow you to choose between a general anesthesia or an epidural anesthesia. A nerve block (femoral or adductor) is usually performed in addition in order to lower the post-operative pain.
In case of conservative treatment: knee instability with giving-ways and finally meniscal tear or cartilage dammage.
In case of surgical treatment (ACL reconstruction): haemarthrosis requiring knee punction or even arthroscopic knee lavage, skin dysesthesia (in the saphenous territory due to the tibial tunnel scar), residual anterior knee laxity if the graft doesn’t heal properly (smoking and unadapted rehabilitation protocols are risk factors), knee stiffness in case of lack of rehabilitation or in case of knee inflammation, the worst case being algodystrophy (complex regional pain syndrom).