Knee Operations Could Lead to Other Injuries

Operating on an anterior cruciate ligament (ACL) injury can lead to other damage to the knee and to changes that remain a full year after the first injury, according to a new study.

A researcher from Lund University (Sweden) assessed 121 patients an additional group of 188 amateur soccer players with ACL injury using quantitative magnetic resonance imaging (MRI) technology. The researcher assessed the first year development of joint fluid (JF), bone marrow lesions (BML), and cartilage morphometry. The images revealed that after one year, the knees that were operated on showed joints that were still swollen, bone marrow damage, and cartilage changes compared to the knees that had not been operated on. The researcher found that as many as 50% of those with an acute ACL tear were misdiagnosed at the clinical examination in the acute phase. More than every second (57%) acutely ACL injured knee had an associated cortical bone depression fracture and almost all had BML visualized on MRI. JF and BML volumes gradually decreased over the first year, although BML was still persistent in 62% of the knees after one year.

One year after the ACL injury, a consistent reduction of cartilage volume, surface area, and thickness was found in the trochlea femur, while an increase of cartilage volume and surface area was found in the central medial femur. Surgical ACL reconstruction was directly and significantly related to increased JF volume at 3 and 6 months; BML volume at 6 months; cartilage volume and area in central medial femur, and decreased cartilage surface area in the trochlea of the femur at one year after injury.

"Some athletes return very early to sports despite the fact that they have these types of complaints. Returning to sports early is often considered as a sign of a successful operation. But the risk of these people developing osteoarthritis in the future may have increased,” said study author Richard Frobell.

The researcher suggests that the strong independent relationship between cortical bone depression fractures and bone marrow lesion volumes shows that a high proportion of ACL injured knees suffer from extensive compressive trauma to the joint cartilage which may, in part, explain the high frequency of osteoarthritis following this injury.


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