Treating Articular Cartilage Defects in the Knee

Chondral injuries to the knee joint refer to damage that’s done to the articular cartilage on the ends of the bones that make up the knee, the femur and tibia, but can also occur on the back side of the patella (kneecap). Chondral injuries are common to the knee joint especially with ACL injuries or multi-ligament injuries. One study reported 23% of acute ACL injuries and 54% of chronic ACL knees had articular cartilage damage. In general, these lesions aren’t painful unless there’s an elevated chondral flap (OCD) or a loose chondral piece. There are several different surgical technique options for treating these types of defects, which are all dependent on the surgeon’s experience and philosophy. The goal of each of these procedures is to partially or completely repair the chondral defect and decrease the risk of developing osteoarthritic changes. When considering options for treatment, one goal of doing any orthopedic procedure is the confidence of the surgeon to say that the outcome with the procedure will provide a better functioning knee and improved quality of life for the patient compared to treatment that allows a natural course of healing with no surgery.

There have only been short-term studies looking at the natural history of articular cartilage defects found at the time of ACL reconstruction. Our clinic did a study with the purpose to determine the long-term objective and subjective outcomes of untreated articular cartilage defects observed at the time of ACL reconstruction. There were 179 patients between 1987 and 2017 who had isolated articular cartilage defects of Outerbridge Grade 3 or 4 in the medial or lateral compartment with only those with intact menisci included. There were 63 medial and 45 lateral lesions with 108 patients at a minimum of 5-year follow up for the study group (60%). This group was matched with a control group with intact menisci and no chondral defect. We looked at age, surgery within 3 years and injury type of semi-acute or chronic. Weight bearing posterior-anterior radiographs were evaluated for osteoarthritis, and recent IKDC (International Knee Documentation Committee*) knee survey analyzed.

What our long-term study showed

The IKDC subjective score at long-term follow up in the study group was 76.1 ± 21.5 compared to the control group of 80.1± 23.1 (p =.182) with a mean age of 30 years in both groups. The mean subjective follow up was 16.7 years and the mean objective follow up was 12.4 years. The patients with articular defects with a grade of 3-4, which is the worst, were more likely to have mild degenerative changes long term. Despite the increased incidence of osteoarthritis, approximately 80% had either normal or nearly normal radiographs at long-term follow up. In addition, there was no difference in groups with moderate to severe radiograph grades and no difference in subjective scores between the two groups. Studies performed by Widuchowski et al. (AJSM 2009) and Gudas et al. (Arthroscopy 2013) showed similar results. Therefore, we must consider what’s right for the patient, not over treat and try non-operative treatment first.

What does non-operative treatment look like? Most physicians will place patients on non-weight-bearing or limited weight bearing and immobilized for 6 weeks. Animal studies show that it takes 2 years for the new cartilage to adapt and mature, so what changes can occur with 6 weeks of restricted weight bearing treatment? We believe appropriate weight bearing can be beneficial for healing and maturation. We’ve discussed in previous blogs the importance of range of motion, particularly extension, in rehab of the knee. The same concept is true with this patient population. When a patient is limited on their weight bearing status, they tend to hold the knee in a flexed posture, which creates a flexion contracture over the 6 weeks, or more, of restriction. Not to mention the huge interruption in lifestyle for patients that being on crutches and limited weight bearing can create post operatively. Because of this, how compliant are patients with these restrictions with work and life expectations? We learned through our noncompliant ACL patients, 30-40 years ago, that those with articular cartilage lesions that were noncompliant with their weight bearing restrictions/crutches had the best results because the weight bearing provides good stimulation and healing. Our recommendations of treating chondral defects are: Restore full symmetrical range of motion and exhaust all efforts to restore full range of motion and strength before doing any surgical procedure.

Before consenting to a potentially unnecessary surgical procedure, always get a second opinion.

*The International Knee Documentation Committee (IKDC) Questionnaire is a knee-specific patient-reported outcome measure. It is considered to be one of the most reliable outcome reporting tools in its category and was one of the instruments used in the popular MOON study. IKDC has been subjected to rigorous statistical evaluation and has proven to be a valid and responsive patient-reported outcome measure (PROM).