OSTEOCHONDRAL INJURIES OF THE KNEE zyxw 0278-5919/01 $15.00 + z .OO TREATMENT OF OSTEOCHONDRAL INJURIES Genetic Engineering Vladimir Martinek, MD, Freddie H. Fu, MD, Chang W. Lee, MD, and Johnny Huard, PhD Articular cartilage lesions in the knee joint are common sports- related injuries.20* zyxw 27 The incidence of articular surface injuries is reported as high as 42% in arthroscopically examined patients with post-traumatic knee disorders.27 In a review of 31,516 knee arthroscopies, 53,569 hyaline cartilage lesions were documented in 62.9% of patients with most of the severe Grade IV cartilage injuries located on the medial femoral c0ndy1e.l~ Injuries of the articular surface originate either from direct trauma or from indirect, twisting injuries of the knee joint. Frequently, injuries of the articular cartilage are associated with anterior cruciate ligament (ACL)ruptures. Magnetic resonance (MR) imaging studies demonstrated bone bruises in 68% of patients with acute ACL tears?" Although no relationship between bone bruises and osteochondral lesions or osteoar- thritis could be proved directly in the past, a significantly higher preva- lence of articular chondromalacia is seen in patients with untreated ACL injuries.2o In a prospective study, Daniel et a1 have demonstrated that degenerative changes of the articular cartilage will develop regardless of the treatment in all patients following an ACL rupture.1s Articular cartilage possesses a limited capability to regenerate, and in most injuries of the articular surface, premature osteoarthritis will From the Department zyxwvu of Orthopaedic Surgery, University of Pittsburgh (VM, FHF, CWL, JH); the Children's Hospital of Pittsburgh OH); and the Department of Molecular Genetics and Biochemistry, University of Pittsburgh OH), Pittsburgh, Pennsylvania CLINICS IN SPORTS MEDICINE zyxwv VOLUME 20 NUMBER 2 * APRIL 2001 403