Reconstruction of the anterior cruciate ligament (ACL) of the knee is a tricky business. Many factors affect the success of the surgery. One factor is how well the graft material attaches to the bone after surgery. However, there is limited information on when this happens or how surgeons can tell when it occurs.
These doctors from Japan followed the way hamstring tendon grafts attached to the bone after arthroscopic surgery to repair a torn ACL. They studied 64 patients, most of whom had injured their ACL during sports activities. All surgeries were done in the same way and by the same surgeon. The authors used MRI scans and physical exams to figure out how well the graft had attached. These tests were done frequently, from two weeks to two years after surgery.
Arthroscopy (in which a tiny camera is inserted into the joint) and X-rays using contrast dye were done at an average of two years after surgery to confirm how well the graft had attached. Almost all of the patients had good results from surgery. Two years later, 97 percent of patients were participating in their normal sports activities. About 90 percent had full range of motion of the knee.
Despite these good results, there were differences in knee stability and stiffness. The authors grouped patients into four different categories according to the way knee stability and strength had developed over the follow-up period. The authors used the test data to determine that one group of patients had early graft attachment, which allowed the best possible healing and rehabilitation. The authors think that one group may have had good attachment only on the tibia (the lower leg bone), but that still allowed a strong, stable knee to develop. The other two groups had poor or no graft attachment, resulting in stretched-out graft tendons–and less stable knees.
The authors note that certain findings from MRIs and physical exams can give doctors clues about how well the graft is attaching to bone. They recommend that patients who seem to show poor graft attachment should go more slowly through rehabilitation to give the graft more time to attach. The authors recommend further research on how to rehabilitate ACL grafts that are not attaching well to the bone.