Tissue-engineered scaffold shows promise as cartilage lesion treatment

Hyalograft C posts positive long-term outcomes in four-year, multicenter study.

Results from a multicenter, four-year follow-up study in Italy have shown that a tissue-engineered, autologous chondrocyte-impregnated scaffold may be an effective treatment option for articular cartilage lesions.

In a presentation at the 6th Symposium of the International Cartilage Repair Society (ICRS), Elisaveta Kon, MD, of the Rizzoli Orthopaedic Institute in Bologna, Italy, said that the use of Hyalograft C (Fidia Advanced Biopolymers) is a safe and effective therapeutic option for cartilage lesions of the knee, including large defects and osteochondritis dissecans.

Hyalograft is composed of autologous chondrocytes on a 3-D biodegradable scaffold made of Hyaff 11, the benzyl ester of hyaluronic acid. Surgeons have used Hyaff 11 in Europe since 1999 in more than 4000 patients.

Advantages of the system include the fact that it does not need a periosteal flap to hold the graft material in place, and it is an arthroscopic-friendly procedure. According to Kon, the majority of Hyalograft procedures in her institution have shifted from open to arthroscopic.

Observational study

Investigators studied a pool of 179 patients with a more than two-year follow-up who were treated at 11 centers throughout Italy.

“This was not a randomized study, but an observational study,” Kon said. The patient population was 63.7% men at a mean age of 38.4 years. The majority of the patients (75.1%) had a single lesion and 24.9% had multiple lesions. The researchers included 246 lesions in the study.

“The average size of lesions was 3.5 cm, and that included bigger lesions up to 19 cm2,” Kon said.

The investigators used knee subjective-evaluative outcomes measures recommended by the ICRS. They included the International Knee Documentation Committee (IKDC) test to measure symptoms, function and activity, and the EuroQol (EQ-5D) instrument to make general health-related quality-of-life assessments.

Overall, they found that at a mean follow-up of 46 months, 93.1% of the patients demonstrated subjective improvements in their knee conditions. “In the quality-of-life assessment, the most important things to us were pain and mobility,” Kon said. “Seventy-three percent were pain-free after the follow-up.” Also, 85.4% said they experienced no mobility problems.

Optimal physical support

According to earlier published data, the tissue-engineered scaffold consists of a network of fibers with various-sized interstices that form an optimal physical support to allow cell-to-cell contact, cluster formation and extracellular matrix deposition. The chondrogenic cells are harvested from the patient, expanded in the laboratory for three weeks and then seeded onto the scaffold, where they stay for one week to adhere, proliferate and deposit an extracellular matrix within the biomaterial. The scaffold is then placed inside the chondral defect without periosteal coverage.

“Most of these do not need any type of fixation, because the graft sticks to the subchondral bone,” Kon said. In cases with compound lesions, they can be held in place with glue.

Kon and Maurilio Marcacci, MD, published additional data in June on the three-year clinical results in a cohort of 141 patients. That study included arthroscopic grading of the knee assessed during second-look arthroscopies in 55 patients. The researchers arthroscopically graded cartilage repair as normal or nearly normal in 96.4% of the scored knees, and most second-look biopsies of the grafted site were histologically assessed as hyaline-like.

IKDC scores indicated 91.5% of the patients showed improvement, 76% had no pain and 88% experienced no mobility problems, according to EQ-5D scores.

For more information:
Kon E. Marcacci M. Articular cartilage engineering with Hyalograft C: four-year clinical results. #3c-4. Presented at the 6th Symposium of the International Cartilage Repair Society. Jan. 8-11, 2006. San Diego.