Immediately after anterior cruciate ligament, or ACL, reconstruction surgery, every patient has pain. With time and active rehabilitation, the pain should lessen and then disappear. There are several causes of pain that starts days to years after surgery. Hospital for Special Surgery researchers found that 6.5 percent of all patients required another knee surgery in the year following an ACL reconstruction.
ACL Surgery
Arthroscopic surgery is done to replace a torn ACL. Using a small camera and shaving instruments, the torn ACL is removed. Holes are drilled into the femur and tibia. The patient's patella tendon with pieces of the patella and tibia bone attached, hamstring tendons, or a cadaver graft is used to replace the ACL. The graft is held in place with screws. In some procedures the screws are inside the bone, while other techniques use metal hardware outside the bone.
Infection
Infection is a serious potential complication of ACL surgery. It presents as increasing pain, swelling and redness. There may be drainage from the surgical incisions. The treatment of an ACL surgery infection includes repeat arthroscopic surgeries to clean out infected areas, and up to six weeks of intravenous antibiotics. Removal of the graft may be required to treat the infection. The American Academy of Orthopaedic Surgeons reports that this occurs after less than 1 percent of ACL surgeries. Infection is most common in the first 90 days after surgery.
Early Pain
In the first month after surgery, blood clots can develop in the leg. If this occurs, patients will develop painful swelling in their leg. This is more common in patients with a family history of blood clotting disorders. Prompt medical evaluation is necessary since a blood clot that travels to the lungs can be fatal. Blood thinning drugs are used to treat the clotting.
Knee pain and motion will be monitored after surgery by the physician and by a physical therapist. Once rehabilitation has begun, a painful loss of motion is seen in 5 to 25 percent of patients according to the AAOS. A second surgery may be required to regain motion of the leg.
Patents may experience pain at the surgical scar sites. The AAOS recommends knee pads it patients kneel frequently since up to 42 percent of patients report some discomfort with kneeling after ACL reconstruction is done with a patella tendon graft. If a screw was placed on the outside of the bone, patients may experience kneeling pain that necessitates removal of the screw.
New Injury
As patients become more active after surgery new injuries can occur. The AAOS cites studies showing that the risk of new injury returns to normal after a successful ACL surgery and rehabilitation. The rate of meniscus tears and rerupture of the ACL graft equals the injury rate of the patient's healthy opposite leg.
When a graft is taken with a piece of patella bone attached there is an increased risk of patella fracture until the patella replaces the bone. This can take several months.
Late Pain
Tearing an ACL requires significant force. Magnetic resonance imaging shows characteristic injury to the bones. The AAOS cites a study showing that 13 years after ACL surgery 79 percent of patients had arthritic changes on X-ray, but almost all of these patients--97 percent--reported near-normal or normal knee functions. The arthritis may become symptomatic later. In the first years after ACL surgery it is not uncommon for patients to complain of pain behind their kneecap. This pain originates from damaged cartilage on the patella surface or abnormal patella tracking. Bracing and therapy often relieve patella pain.
The AAOS reports that after ACL surgery up to a third of patients experience instability in their knee. When testing is done, almost all patients have some laxity compared to the non-injured legs. Patients compensate for knee instability by using their leg muscles.
Avoiding Complications
After undergoing ACL surgery, patients want to return to doing their normal activities without pain. To regain function, therapy directed at regaining normal strength, flexibility and balance sensation in the leg is prescribed for all ACL surgery patients. Bracing the knee for a year after surgery does not improve outcomes.
The American Academy of Orthopaedic Surgeons reports that patients who smoke or gain more than 15 lbs. have poorer outcomes.
Any severe knee pain that develops after ACL surgery should be evaluated by a physician.
References
- American Academy of Orthopaedic Surgeons: Your Orthopaedic Connection: ACL Injury: Does It Require Surgery
- "American Academy of Orthopaedic Surgeons, Orthopaedic Knowledge Update 9"; J. Fischgrund, ed; 2009
- "American Academy of Orthopaedic Surgeons, Comprehensive Orthopaedic Review"; J. Lieberman, ed.; 2009
- "The Journal of Bone and Joint Surgery"; Epidemiology of Anterior Cruciate Ligament Reconstruction. Trends, Readmissions, and Subsequent Knee Surgery; Stephen Lyman, Panagiotis Koulouvaris, Seth Sherman, Huong Do, Lisa A. Mandl, and Robert G. Marx; 2009
