Shoulder Cartilage Damage

Articular cartilage is a thin, whitish, glistening layer of protective tissue that covers the joint surfaces of bones. Articular cartilage is composed of hyaline cartilage cells, which have many unique properties that allow it to function effectively as a smooth and lubricious load-bearing surface. Small defects in the articular surface can cause pain and restrict range of motion. When traumatized or injured, new hyaline cartilage cells do not replace damaged hyaline cartilage cells. Several joint diseases (e.g. rheumatoid arthritis) are complex inflammatory disease processes that slowly deteriorate the overall joint surface and often affect multiple joints at the same time. Arthrosurface's technology is not intended to treat these systemic joint diseases.

A different type of joint disease is the result of injury to a relatively small, localized area of the articular surface. These injuries create defects in the articular surface. These injuries or defects can be caused by either acute or repetitive trauma, as when one bony surface strikes against the opposing bony surface. The trauma may have occurred from athletics, a fall, car crash or other high-energy event or impact. These defects may also be caused by chronic conditions that cause the joints to load disproportionately on one side or area. These joint surfaces appear largely normal but have one or more localized lesions or defects. These defects range from a softening of the articular cartilage to complete loss of articular cartilage thus exposing the underlying bone.

Orthopedic surgeons classify the severity of the defect by assigning a grade from one to four, four being the most serious. A severe lesion (grade IV) looks like a hole or deep pockmark in an otherwise smooth, shiny articular surface. The severity (depth, size and location) of the lesion will often determine whether and what type of surgical intervention may be employed. Grade IV lesions, in particular, are defined as full-thickness defects where the underlying bone is exposed. Many physicians also believe that smaller lesions deteriorate over time and, therefore, Grade III lesions are likely to become Grade IV lesions.