The Effect of Hyaluronic Acid on a Rabbit Model of Full Thickness Articular Cartilage Repair

Introduction Knee injuries are common in both the young and the athletic populations. While ligamentous and meniscal trauma constitute the majority of knee injuries, articular cartilage damage can and does occur frequently. Early detection of articular cartilage damage has dramatically improved with the advent of MRI, and focal defects as small as 1mm may now be detected(1). “Benign neglect” has been the treatment mainstay for small defects, although more aggressive treatments have included arthroscopic debridement alone or combined with drilling or microfracture of the involved area. Despite treatment, many articular lesions do progress, and ultimately the knee develops osteoarthritic changes. A variety of methods has been employed to enhance the repair of full-thickness cartilaginous defects, including transplantation of mesenchymal stem cells, perichondrial tissue, or isolated chondrocytes. These tissues have been transplanted alone and in combination with biodegradable implants(2,3,4,5,6,7,8). Recently, implantation of bone morphogenic protein (BMP) absorbed on collagen was shown to improve the quality of the tissue in a repaired full thickness defect. While these techniques appear attractive, they are all invasive. A simple and cost effective medical therapy capable of augmenting the natural healing process would represent a significant advancement in the management of acute full thickness cartilage injuries. Over the past decade intra-articular injection of hyaluronate has been utilized in the management of osteoarthritis of the knee, and more recently has been shown to improve meniscal healing in an acute injury model (9). To examine the potential benefit of hyaluronate on cartilage repair, the effect of serial intra-articular hyaluronate injections on the healing of full thickness cartilage defects was explored utilizing a rabbit model.