Leaving a severe knee cartilage lesion untreated for years may not increase OA risk

Issue: January 2011

Wojciech Widuchowski

OSLO — Untreated single Outerbridge grade 3 and 4 cartilage lesions on the femoral condyle, tibia or patella achieved good clinical outcomes at more than 15 years mean follow-up in a study by researchers at the District Hospital of Orthopaedics and Trauma Surgery in Piekary Slaskie, Poland.

Patients with patellar lesions had inferior results compared to those with femoral or tibial lesions, according to investigator Wojciech Widuchowski, MD, PhD.

“We documented good overall results in both groups. Worse results were in patients with their lesions located within the patella,” Widuchowski said during his presentation at the 2010 ESSKA Congress.

To better understand the natural history of these types of knee cartilage lesions when left untreated for several years, Widuchowski and colleagues identified 37 isolated, yet severe cartilage lesions in 24 men and 13 women from among 4,121 knee arthroscopies they performed between 1991 and 1994. They observed the lesions radiographically via the Kellgren-Lawrence scale and assessed the patients’ mean Lysholm, Tegner and WOMAC scores through an average of 15.3 years.

According to Widuchowski, 26 lesions were left untreated, but the others were treated with debridement, shaving or loose body removal.

At final follow-up, researchers examined 33 of 37 patients, comparing results in the two subgroups with tibio-femoral lesions or with patellar lesions.

In their abstract, Widuchowski and colleagues wrote that 39% of patients had osteoarthritic changes at follow-up.

“In the patients in the femorotibial group, there was a relationship between the incidence of tibiofemoral and patellofemoral osteoarthritis,” Widuchowski said.

“In the patellar group there was a significant negative correlation between the baseline and postoperative scores. Osteoarthritic changes were documented in 13 patients. There was no difference in the osteoarthritis frequency and severity between injured and uninjured knees.”

The study’s limitations — a small number of patients and a comparison of injured to uninjured knees rather than to matched controls — must be understood, as well as the goal of the research, which was to better understand the long-term natural history of untreated severe lesions and identify patients who may be more prone to developing osteoarthritis, Widuchowski noted. “More randomized long-term follow-up studies are needed to show that the treatment of severe cartilage lesions, especially sophisticated and expensive methods, provide improvement over the natural history and are effective at stopping development of osteoarthritis,” he said. – by Susan M. Rapp

References:

Widuchowski W, Lukasik P, Koczy B, et al. Long-term clinical and radiological assessment of untreated severe cartilage damage in the knee: a natural history study. Paper FP14-147. Presented at the 2010 ESSKA Congress. June 9-12, 2010. Oslo.

Widuchowski W, et al. Scand J Med Sci Sports. 2010 Jan 31. [Epub ahead of print]

Wojciech Widuchowski, MD, PhD, can be reached at the Department of the Knee Surgery, Arthroscopy and Sports Traumatology, District Hospital of Orthopaedics and Trauma Surgery, Piekary Slaskie, Poland; e-mail: sportmed@sportmed.com.pl.

This is one of the few studies observing the natural development of cartilage lesions in weight-bearing zones. This seems to confirm clinical observations that in some cases even a substantial cartilage lesion may not necessarily lead to osteoarthritis. Some of this study’s weaknesses are that it offers no clear explanation of why patellofemoral osteoarthritis gets worse, and it lacks comments on leg axis and patellofemoral alignment. Follow-up with MRI would have been important to demonstrate development of lesions. These are interesting results and more studies like this are needed.

– Peter Behrens, MD
Orthopaedic surgeon, Hamburg, Germany