Treatment of Full-thickness Articular Cartilage Lesions of the Knee in High-demand Athletes with Autologous Chondrocyte Transplantation

INTRODUCTION Soccer is the most popular sport worldwide with about 200 million currently registered active players.1 The frequency of soccer injuries is estimated at 10-35 per 1000 hours of competition, with the majority occurring in the lower extremities. Knee injuries account for 15-40% of soccer-related injuries.2,3 While numerous studies have described injuries of the cruciate ligaments and menisci in soccer players, little information is available on articular cartilage injuries in these highdemand athletes.4 This lack of data is surprising since the prevalence of acute and chronic articular cartilage lesions in the cruciate-deficient knee is well documented.5,6 The lack of available data on cartilage lesions in soccer players is not completely understood, but may be related to the limited treatment options available for these injuries in the past. Levy and coworkers have recently confirmed the increasing frequency of isolated chondral injuries in collegiate, professional and worldclass soccer players. They concluded that the observed increase resulted from both the growing popularity of the sport and the increased awareness of chondral injuries due to emerging new techniques for cartilage repair.4 In full-thickness injuries to the articular cartilage, disruption of the articular surface occurs without concomitant violation the subchondral bone, which precludes access to the subchondral vasculature. Since no bleeding occurs, the avascular cartilage can only promote repair via a transient increase in mitotic and metabolic activity in the surviving chondrocytes bordering the defect. Due to this limited response, the newly synthesized matrix is nearly always insufficient to fill the defect and restore the articular surface. Laboratory studies have shown that because of the qualitative and quantitative deficiencies in the spontaneous repair tissue, the newly formed matrix deteriorates quickly with loading of the joint surface.7 Clinically, this leads to progression of the lesions, with pain, swelling, catching of the joint, and a dramatic reduction of the patient’s quality of life and ability to participate in athletic activities.8 Repair of articular cartilage has been difficult due to the pathophysiology and molecular biology of cartilage tissue, and traditional treatment methods have not produced reliable and lasting results.9,10 The treatment of articular cartilage lesions in the knee has recently gained considerable interest due to the development of new techniques. The successful repair of articular cartilage lesions of the human knee by autologous chondrocyte transplantation was first reported by Brittberg in 1994.11 Recent follow-up data demonstrates excellent results with the use of this technique up to eleven years.12,13 However, an evaluation of autologous chondrocyte transplantation in high-demand athletes, such as soccer players, has not yet been performed. METHODS Soccer players with acute or chronic articular cartilage lesions were treated with autologous chondrocyte transplantation at Brigham and Women’s Hospital, Boston, MA, Santa TREATMENT OF FULL-THICKNESS ARTICULAR CARTILAGE LESIONS OF THE KNEE IN HIGH-DEMAND ATHLETES WITH AUTOLOGOUS CHONDROCYTE TRANSPLANTATION