So many people in this country are having anterior cruciate ligament (ACL) surgery, it’s beginning to seem like a common place problem/solution. ACL ruptures haven’t reached epidemic proportions but with 200,000 cases reported each year, it is a significant problem.
Surgery to reconstruct the torn ligament is quite successful. But studies do show up to a 10 per cent failure rate after the primary (first) surgery. In this report, surgeons from the Mayo Clinic in Rochester, Minnesota tell us about the results for patients who have two or more ACL surgeries.
Repeat or revision surgery for ACL reconstruction is often needed because the tunnels drilled through the femur (thigh bone) for the graft tissue to go through are placed too far forward the first time. In other cases, damage to the cartilage on the surface of the knee joint and misalignment of the lower extremity contribute to failure of the primary (first graft) procedure.
Looking back over the records of patients who had at least two ACL reconstructions at the Mayo Clinic, they found a total of 15 charts. The patients ranged in ages from 18 up to 57. Two-thirds of those cases required new femoral tunnels. Two-thirds had severe chondral (cartilage) lesions. And three-fourths had a meniscal tear.
As it turned out, the first two factors (placement of the femoral tunnels and chondral lesions) were risk factors for graft reconstruction failure. The third factor (damaged meniscal cartilage) was not directly linked with graft failures. A graft failure was defined as a rupture of the graft tissue or knee joint instability. Another risk factor for a failed ACL reconstruction is obesity. Patients with a body mass index (BMI) measure of 29 or higher had fair to poor results after the first surgery.
The authors readily admit that ACL revision of primary reconstructions can be a difficult and challenging surgery. There are many factors to consider including a limited choice of graft tissue, fixing the graft in place to create a stable response, unusual/unnatural anatomy, and difficulty finding the right spot and then creating correct tunnels for the final step of the initial surgery.
Patients also have high expectations, especially when they are athletes hoping to return to their sport equal to (if not better than) before surgery. Many of these ACL injuries (and re-ruptures after surgery) occur in high-demand sports athletes. As the results of this study showed, trauma and overuse lead to recurrent instability most often in this patient population.
But good-to-excellent results are possible even after repeated ACL surgical revisions. These outcomes were measured using clinical tests (e.g., pivot-shoft test, Lachman score, International Knee Documentation Committee scores), X-rays, and level of function in activities of daily living (ADLs) and recreational/sports activities. Details of revision surgical techniques used are included in the article for surgeon who may be interested.
In conclusion, although this was a small study (only 15 patients), the results did provide some valuable insight into the risk factors for re-rupture and need for surgical revision after a primary ACL reconstruction surgery. Despite good clinical results, patients reported a reduction in their activity level after repeated surgeries. Most of the time, this was because they chose to restrict sports participation.