Open growth plates are characterized by increased numbers of undifferentiated chondrocytes (stem cells) which are precursors to both bone and cartilaginous tissue. As a result, open growth plates allow for more of the stem cells necessary for repair in the affected joint. Unstable, large, full-thickness lesions (stage III and IV) or lesions of any stage found in the skeletally mature are more likely to fail non-operative treatment. These lesions offer a worse prognosis and surgery is required in most cases. Epidemiology
OCD is a relatively rare disorder, with an estimated incidence of 15 to 30 cases per 100,000 persons per year. Widuchowski W et al. found OCD to be the cause of articular cartilage defects in 2% of cases in a study of 25,124 knee arthroscopies. Although rare, OCD is noted as an important cause of joint pain in active adolescents. The juvenile form of the disease occurs in children with open growth plates, usually between the ages 5 and 15 years and occurs more commonly in males than females, with a ratio between 2:1 and 3:1. However, OCD has become more common among adolescent females as they become more active in sports. The adult form, which occurs in those who have reached skeletal maturity, is most commonly found in people 16 to 50 years old.While OCD may affect any joint, the knee—specifically the medial femoral condyle in 75–85% of knee cases—tends to be the most commonly affected, and constitutes 75% of all cases.
However, some physicians have preferred to use undifferentiated pluripotential cells, such as periosteal cells and bone marrow stem cells, as opposed to chondrocytes. These too have demonstrated the ability to regenerate both the cartilage and the underlying subchondral bone.Similar to OATS, arthroscopic articular cartilage paste grafting is a surgical procedure offering cost-effective, long-lasting results for stage IV lesions. A bone and cartilage paste derived from crushed plugs of the non-weight-bearing intercondylar notch can achieve pain relief, repair damaged tissue, and restore function. Unstable lesions
Some methods of fixation for unstable lesions include countersunk compression screws and Herbert screws or pins made of stainless steel or materials that can be absorbed by the body. If loose bodies are found, they are removed. Although each case is unique and treatment is chosen on an individual basis, ACI is generally performed on large defects in skeletally mature people. Rehabilitation
Continuous passive motion (CPM) has been used to improve healing of the articular surface during the postoperative period for people with full-thickness lesions. It has been shown to promote articular cartilage healing for small (< 3 mm in diameter) lesions in rabbits. Similarly, Rodrigo and Steadman reported that CPM for six hours per day for eight weeks produced an improved clinical outcome in humans.A rehabilitation program often involves protection of the compromised articular surface and underlying subchondral bone combined with maintenance of strength and range of motion. Post-operative analgesics, namely a mix of opioids and NSAIDs, are usually required to control pain, inflammation and swelling.