Anterior Cruciate Ligament Reconstruction Overview
In people who have suffered a torn anterior cruciate ligament (ACL), anterior cruciate ligament reconstruction (ACLR) can be an option to treat ongoing knee instability. This is an arthroscopically assisted day surgery procedure in which tendons from the same leg are taken through a small incision at the front of the knee and converted into a graft. The graft is then passed through bone tunnels to replace the torn ACL. Sometimes additional cartilage damage must be corrected during the same procedure. Patients use crutches for the first 3 weeks, and will need subsequent physiotherapy. Return to heavy work and sports usually takes several months.
Anterior Cruciate Ligament Reconstruction Details
The anterior cruciate ligament (ACL) is one of the main stabilizing structures of the knee. It can be torn with forcible contact injuries, or in sudden twisting mechanisms. More than simply a “sports injury”, it can occur in many situations, and sometimes includes damage to cartilage or bone. It does not show up on a simple X-ray, and can therefore sometimes be missed initially. An MRI is often helpful to confirm the diagnosis.
A torn ACL usually does not heal on its own, leading to dysfunctional instability, swelling and locking of the knee. Repeated giving way episodes can sometimes cause additional cartilage tearing. It can interfere with both with sporting and vigorous activities but also sometimes with simple day to day activities. An ACL brace and physiotherapy can be helpful to cope with the condition. After an ACL tear there will be an increased likelihood of osteoarthritis in that knee in the future, whether or not an anterior cruciate ligament reconstruction is performed.
Sometimes these non-operative measures are ineffective or less desirable, especially in active or sports minded individuals. An anterior cruciate ligament reconstruction (ACLR) can then be considered for some individuals, usually from their teens to their 40’s. The benefits and challenges of this option will be discussed in the office. It is primarily intended to eliminate the instability episodes and allow more predictable and aggressive function. If an ACL brace has not yet been provided, it will be prescribed. If ACLR is booked, a cooling cuff will be arranged for post operative use, and should be brought to the hospital on the day of surgery.
An ACLR is an arthroscopically assisted procedure performed as a day surgery under a general or spinal anaesthetic. There are a number of graft options, but we usually use a hamstring technique. Two hamstring tendons are taken through a small incision at the front of the knee, and doubled over to fashion a graft which will become the new ACL. It is passed through drilled tunnels in the tibia and femur to recreate the position of the original ACL, and anchored with absorbable screws.
Sometimes there is additional meniscus or joint surface cartilage damage that must be addressed at the same time, either through repair or trimming of tissue. Long acting freezing is injected, and a small drain is placed in the knee, to be removed prior to discharge. Postoperatively a cooling cuff is applied to the knee. The patient goes home with crutches, and can be partial weight bearing on the operated leg. A prescription for pain killers and a blood thinner is provided. Prescribed exercises can begin immediately, and physiotherapy will be arranged at the first follow up visit.
A standardized rehabilitation program is prescribed, and optimal results depend heavily on compliance with this program. Fairly comfortable walking is expected by 4 to 6 weeks. Biking, running, and swimming are gradually introduced and competitive sports are usually allowed by about 6 months. A brace is recommended for the first 6 months back in sports, to allow the harvested hamstring tendons to regenerate completely. Full recovery of strength may take up to a full year.
All operations have potential risks, and for this procedure these include anaesthetic risks, infection (approximately 1 in 100 cases), blood clots in the leg or lungs (1 in 500), persistent stiffness (rare) or blood vessel or nerve injury (extremely rare). Smoking and obesity can adversely affect results. Occasionally there can be persistent knee symptoms despite successful surgery, as the graft provides at best only an approximation of the original ACL. An ACL graft can also tear with further injury, though this is not common.