Joint, or articular, cartilage covers the ends of bones and allows for joints to glide smoothly with minimal friction. Cartilage damage, or chondral defects, can be caused by acute trauma, such as a bad fall or sports-related injury, or by repetitive trauma, such as general wear over time. Unlike other tissues in the body, joint cartilage has no innate ability to repair itself, making any injury permanent. Left untreated, knee cartilage damage can deteriorate into debilitating osteoarthritis and chronic pain, ultimately necessitating a joint replacement procedure.
We estimate, based on internal research, that over 500,000 knee cartilage procedures are performed annually in the United States primarily in the form of debridement, microfracture, conventional autologous chondrocyte implantation (ACI) and osteochondral grafting. Debridement and microfracture procedures are the most frequently performed surgical procedures for the treatment of cartilage damage, accounting for an estimated 90% of all such procedures according to company research and materials from a 2009 meeting of the Cellular Tissue and Gene Therapies Advisory Committee of the FDA.
Debridement is an arthroscopic procedure that involves removal of injured or loose tissue debris, but does not attempt to repair cartilage damage. Debridement surgery typically reduces pain symptoms, but does not repair cartilage damage.
Microfracture is considered the current standard of care for chondral defects due to its ability to improve symptoms in specific types of patients, its simplicity, its safety profile and the lack of other viable alternatives. However, microfracture has been unsuccessful in reliably solving the underlying problem of cartilage damage because the repair tissue formed by the procedure is often fibrous cartilage, or scar tissue, that is incapable of withstanding the normal shock and shear forces that joint cartilage sustains.
In addition to its inability to solve the underlying problem – damage to the articular cartilage – microfracture is associated with numerous other drawbacks and limitations, including the following:
- Modest and Variable Efficacy
- Limited Long-Term Patient Benefits
- Extended Patient Recovery
ACI and osteochondral grafting are procedures generally reserved either for patients who have failed prior cartilage procedures or those with very large cartilage defects. While studies indicate beneficial outcomes for patients receiving these treatments, both have drawbacks and limitations similar to those affecting debridement and , and also are associated with the following:
- Technically Demanding Surgeries
- Negative Safety Profile
- Two-year clinical endpoints