Complications of ACL Reconstruction
Author: Dimitrios Giotikas MD, PhD
ACL reconstruction, as any surgical intervention, is not without risks:
Anterior Knee Pain
It is the most common complication of ACL surgery is pain. This complication is highest in patients who have surgery performed with a patellar tendon graft. These patients can even have complications including patellar fracture and patellar tendon tear, although these are very uncommon. However, all patients, even those having hamstring grafts or donor grafts, can also have symptoms of anterior knee pain. Typical anterior knee pain is thought to be a result of altered mechanics of the joint, and can often be overcome with extensive physical therapy. Adherence to post-operative rehab protocols is important for athletes to ensure their knee mechanics improve.
Infection is a rare but serious complication. When the infection is inside the knee joint, there is concern about the ACL graft becoming infected. Your body cannot effectively fight infection on the graft, and sometimes the graft needs to be removed in order to cure the infection. Taking steps to avoid infection include following your surgeon’s specific instructions both before and after surgery. Many surgeons recommend cleaning the knee with antibacterial soap prior to surgery, and then it is important to follow any specific bandage instructions after surgery. If you do have signs of infection including fever, chills, increasing knee swelling or pain, let your surgeon know as soon as possible.
Re-Rupture of the ACL Graft
Repeat rupture of the ACL graft is also uncommon, but does occur. ACL grafts are very strong. In fact, autograft tissue (tissue from the patellar tendon or hamstring tendon) is stronger than your own ACL. Whenever there is a re-rupture of the graft, your surgeon should carefully assess for possible technical failures of the first surgery. Possible problems that can lead to re-tear of the ACL include suboptimal positioning of the graft, improper tension on the graft, or failure of the fixation of the graft.
Blood clots (DVT)
the risk of a blood clot forming and causing problems is very low (about 1 in 1,000); if you're thought to be at risk, you may be given medication to prevent blood clots forming.
Stiffness after ACL surgery is frequently encountered. Fortunately, most patients with stiffness can address this complication with aggressive rehabilitation.
While most cases of stiffness can be addressed with rehab, one exception is called a cyclops lesion. A cyclops lesion occurs when a ball of scar tissue forms in the front of the knee, causing an inability to fully straighten the knee after ACL surgery. An arthroscopic surgery to clean out this scar tissue is often necessary for patients with a cyclops lesion.
The most critical step to avoid stiffness is to get the knee moving quickly after ACL surgery. In the past, doctors used specialized machines to bend the knee, called CPM machines, although these have not been shown to lead to long-term improvement. Many surgeons are becoming more aggressive with early rehab, and avoiding braces after surgery, in order to get the knee moving quickly.
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