Arthroscopic ACI useful for large cartilage defects

Biopsies confirm development of immature chondrocytes and immature cartilage.

VANCOUVER, British Columbia — A new arthroscopic technique for transplanting autologous chondrocytes appears effective for patients with large articular cartilage defects.

Stephen P. Abelow, MD, presented the results of a study evaluating Membranous/Matrix Autologous Chondrocyte Implantation (MACI) at the Arthroscopy Association of North America 24th Annual Meeting. The procedure is a variation of Autologous Chondrocyte Implantation (ACI). In MACI, however, surgeons attach the chondrocytes to an absorbable membrane and implant it arthroscopically, Abelow said.

“The problem with the [ACI] procedure was that it involved a periosteal harvest, arthrotomy and suturing of the periosteum,” he said. “It really could not be done arthroscopically. There were sites that were inaccessible to sutures, and creating a water tight seal was particularly hard,” he added.

“MACI allows for an all arthroscopic ACI procedure,” Abelow told the OrthoSuperSite. “It’s just the next step in the progression of cartilage regeneration.”

Surgical procedure

In performing MACI, the surgeon harvests autologous chondrocytes from a nonweight-bearing area of the ipsilateral knee and expands the cells in a culture. The surgeon then impregnates the cells onto an absorbable bilayer of purified porcine collagen I/III membrane (Chondro-Gide, Geistlich Pharma AG), seeding the cells in the membrane’s porous side in a 3-D type of matrix, according to the study.

The surgeon attaches the membrane to the cartilage defect using fibrin glue, either arthroscopically or by mini-arthrotomy, and can also use standard sutures or pins, Abelow said.

The procedure requires normal anatomical alignment, and surgeons may need to perform an osteotomy before transplanting the membrane, he noted.

The postoperative protocol includes early motion, nonweight-bearing for about eight weeks and wrapping the joint in an ace bandage. Patients can also use a continuous passive motion machine, he said.

Decreased pain

Abelow and colleagues in Madrid, Spain, evaluated MACI in 50 patients aged 20 to 45 years — 42 knees and eight ankles. All underwent surgery at the Clinica CEMTRO, Madrid, with follow-up ranging from two months to over two years, according to the study.

All patients had full thickness deep chondral lesions confirmed by MRI. Knee lesions ranged from 2.5 square cm to 20 square cm. Medial femoral condyle lesions accounted for 52% of these cases. Ankle lesions ranged from 3 square cm to 6 square cm, with the medial aspect of the talus involved in 88% of cases. Thirty-eight patients had osteochondritis dissecans, 11 had prior meniscectomies and one had a chondropathy.

Preoperatively, 32 patients (64%) had pain levels greater than 6 on the Visual Analog Scale. Postoperatively, pain decreased to between 0 and 3 for 70% of patients. At final follow-up, only two knee patients (4%) reported pain levels greater than 6, according to the study.

Of 41 patients who had prior surgery, 70% achieved good results. Eight of nine patients (89%) who did not have prior surgery had good postop results, Abelow said.

Biopsies performed during follow-up confirmed the development of immature chondrocytes and immature cartilage, according to the study.

Editor's Note: MACI is not approved for use in the United States.

For more information:
Guillen P, Abelow SP, Jaen TF. Arthroscopic matrix/membranous autologous chondrocyte implantation for the treatment of large chondral defects of the knees. #67. Presented at the Arthroscopy Association of North America 24th Annual Meeting. May12-15, 2005. Vancouver, British Columbia, Canada.