Arthroscopic ACL reconstruction for ACL tears
Several ligaments stabilize the human knee: the ACL, the PCL, the MCL, the LCL and the posterolateral corner complex. Injury to the ACL can lead to instability of the knee.
Reviewed February 21, 2015, by Dr. Seneviratne
Symptoms
ACL tears can lead to knee instability, which in turn may cause microscopic damage to the articular cartilage and osteoarthritis later on. There are broadly two categories of patient: copers, roughly 10%, and non-copers. Copers are able to continue daily activities and sport without instability, generally because they have very strong hamstrings that compensate for the missing ACL. Non-copers have overt instability with sport, and sometimes with simple walking. Knee pain usually settles about three weeks after the injury, and patients can generally walk without much difficulty.
Why it happens
ACL injuries can occur in isolation or in combination with other injuries — usually ACL, LCL and posterolateral corner — and meniscal tears frequently occur alongside them. They typically happen in sports involving lateral movement, such as soccer, skiing and football.
Women have a five- to sevenfold increased risk of ACL rupture. This is thought to relate to anatomic variation, neuromuscular control and other factors. Hormonal explanations have largely been disputed through rigorous study, including research published by Dr. Seneviratne on the influence of estrogen on ACL tenocyte function.
How it is diagnosed
Diagnosis begins with a detailed history and a thorough physical examination. X-rays are the most important initial study; for the knee these are specialised, usually weight-bearing views, meaning you will be standing. An MRI may be added to look more closely at the ligaments and soft tissues.
Treatment
Treatment depends on age, activity level and degree of instability, among other factors. Older patients are usually treated non-operatively with physical therapy. Athletes in high-demand sports such as basketball, soccer, football and skiing generally require surgical reconstruction. Dr. Seneviratne evaluates each patient and recommends the best course.
The operation
Surgery is performed arthroscopically, with a small incision at the front of the knee to harvest the graft. The graft can be the central third of the patellar tendon or the hamstrings. It is passed through two precisely placed tunnels in the tibia and femur and fixed with titanium screws, reconstructing the ligament anatomically. Surgery takes about 60 to 90 minutes and is an outpatient procedure — patients go home the same day. Dr. Seneviratne performs a footprint ACL reconstruction using flexible reamers and the anteromedial portal technique.
Recovery
You will be placed in a brace and allowed to bear weight as tolerated, starting range of motion exercises immediately. Physical therapy usually begins on the first post-operative day, and certainly within a week, for swelling control, muscle activation and other measures to aid healing. Rehabilitation for this injury can last up to six months.
Common questions
Where can I get more detail on rehabilitation?
Dr. Seneviratne has a detailed booklet on this, available in the Recovery section of this site.
What are the risks of ACL reconstruction?
Infection, bleeding, damage to nerves and blood vessels, blood clots in the legs (DVT), and clots that break off and travel to the lungs (pulmonary embolus). Knee stiffness is an additional risk.
Is quadriceps weakness permanent?
Permanent quadriceps weakness may occur in about 20% of patients undergoing ACL reconstruction, regardless of graft choice. Several factors contribute, including use of a femoral nerve block at the time of surgery and inadequate rehabilitation afterwards.
What are the graft choices?
The ACL can be reconstructed with your own tissue — the central third of the patellar tendon with two bone plugs harvested from the patella and tibia, or hamstring tendon. Allograft (donor tissue) can also be used. Dr. Seneviratne prefers the patient's own tissue, as it heals faster and eliminates the already very remote risk of transmitting disease such as HIV or hepatitis B. There is a role for allograft, and he customizes the choice to each patient.
What is the re-rupture rate?
For bone-patellar tendon-bone autograft reconstructions, about 3%. For hamstring reconstructions, 4–13%. For allograft (donor tissue) reconstructions, about 20%.
How long is recovery?
Early healing is six weeks. Full, mature healing can take up to a year, and most professional athletes are out of sport for a full year. That said, most patients walk without a limp at about six to eight weeks and can jog on a treadmill at eight weeks.
Can I return to my pre-injury level of play?
Yes. Many professional athletes have returned to their previous level after ACL reconstruction.
Knee video
Back to work in six weeks after robotic assisted total knee replacement
Robotic knee replacement offers the advantage of minimising surgical trauma. The implant is positioned to a precision of less than 1mm on a computer screen before a single incision is made. Once Dr. Seneviratne is satisfied with the implant position, the robot makes precise cuts in the bone, allowing implantation with less surgical trauma, a faster recovery and an earlier return to daily activity and work. Note that this is anecdotal; research studies are ongoing to define the merits of robotic assisted knee surgery.
Left partial knee replacement for single compartment osteoarthritis
Robotic assisted partial knee replacement offers a rapid recovery with an early return to function.