by John Gever

Surgery for torn knee ligaments and meniscal cartilage may have improved patients’ short-term outcomes, but it did not seem to prevent the eventual development of osteoarthritis, researchers said.

A study that followed 326 patients for a mean of 10 years found that radiographic findings shortly after the initial knee injury strongly predicted the long-term clinical course, with no significant difference seen between those who did and did not have knee surgery, reported Kasper Huetink, MD, of Leiden University in the Netherlands, and colleagues.

“Localized knee osteoarthritis developed, irrespective of treatment, from ACL [anterior cruciate ligament] and meniscal injuries identified at MR [magnetic resonance] imaging performed a decade ago in patients with subacute knee symptoms,” they wrote online in the journal Radiology.

Patients who had ACL ruptures and meniscal tears had a substantially increased risk for common features of osteoarthritis — such as joint space narrowing, cartilage or bone marrow lesions, and/or osteophytes — when compared with patients who had other types of knee injuries, the researchers found.

Huetink and colleagues suggested that changes in biomechanical loading resulting from the ligament or meniscal tears were responsible for the specific patterns of osteoarthritis findings seen in the sample.

In particular, they indicated, diffuse medial cartilage loss typically follows medial meniscus tears, whereas lateral meniscal tears result in focal lateral cartilage loss. ACL ruptures eventually produce both medial and lateral abnormalities.

The study examined long-term radiographic outcomes in an initial cohort of 855 patients (those not lost to follow-up) originally seen at three Dutch hospitals in 1996 and 1997.

The original cohort was recruited for an assessment of MRI scans for diagnosis of knee injuries. Huetink and colleagues found that the 326 available for MRI at follow-up did not differ from the other members of the cohort in most respects. The main differences were that those included in the present analysis had more ACL tears (15% versus 9% among those lost to follow-up, P=0.021) and somewhat fewer had no meniscal tears or ACL ruptures (47% versus 54%, P=0.048).

About 37% had medial meniscal tears and 21% had lateral meniscal tears among those in the follow-up group.

Huetink and colleagues found odds ratios ranging from 2.0 to upwards of 15 for particular osteoarthritis features among patients identified with these injuries at the initial MRI exam, compared with patients without ACL or meniscal tears.

For example, the odds ratio for joint space narrowing in the medial tibial compartment was 5.5 for ACL ruptures (95% CI 1.6 to 18.6) and 15.3 for medial meniscal tears (95% CI 3.3 to 71.8), whereas there was no significant increase in risk for this outcome in patients with lateral meniscal tears (OR 0.8, 95% CI 0.2 to 2.6).

However, the odds ratio for joint space narrowing in the lateral tibial compartment for patients with lateral meniscal injury was 10.7 (95% CI 3.8 to 29.8).

The researchers did not report specific numerical findings for patients undergoing surgical treatments versus others, but they indicated that surgery did not specifically affect the long-term outcome.

“The ORs for all structural abnormalities in the patients treated with ACL reconstruction or partial meniscectomy were not significantly different from those for the patients who were not treated,” they wrote, noting that the 95% confidence intervals all spanned 1.

Huetink and colleagues indicated that the study’s major limitation was the low rate of follow-up (38%) among the original cohort. They also noted the possibility that patients with persistent knee problems might have been more likely to participate in the study, potentially biasing the findings.

In addition, the researchers had no way to control for the possibility that patients receiving surgery might have had worse outcomes if they had been treated differently.

John Gever is a MedPage Today Senior Editor.

Originally published in MedPage Today. Visit MedPageToday.com for more orthopedics news.