New stem cell-rich collagen paste repairs defects with success

Researchers repair defects with a paste of bone marrow aspirate, particulate collagen.

KEYSTONE, Colo. — A new talar osteochondral defect repair technique using stem cell-rich collagen paste produced excellent results in maintaining ankle joint viability and mobility in patients, according to Stuart D. Miller, MD, who presented the study results at the 2011 Annual Meeting of the American Orthopaedic Foot and Ankle Society.

“This is an extension of the microfracture concept,” Miller said. “We are trying to increase the number of stem cells and give it a more three-dimensional scaffold so it can form hyaline cartilage instead of fibrocartilage.”

The stem cell-rich collagen paste was successful in returning many patients to normal activity. Miller and his co-investigator Lew C. Schon, MD, have performed the procedure on 25 patients thus far during a 3-year period.

“We have a number of home runs where a patient has had complete resumption of athletic activity including runners going back to running 12 to 15 miles per week,” Miller said.

Hyaline cartilage more durable

The stem cell-rich paste, according to Miller, works better than microfracture surgery alone because the hyaline cartilage created by the paste is more durable than the fibrocartilage formed by microfractures.

Miller conceived the idea from another orthopedist at Rizzoli Insitute in Italy, Francesca Vannini, MD. She used a matrix-induced autologous chondrocyte implant (MACI, Genzyme Europe BV, Naarden, The Netherlands) as a matrix for cartilage stem cells growth. These matrices are not available in the United States, Miller explained, so he and his team used collagen from Integra Life Sciences that is used for wound filling as the substrate.

How it is made

To create the paste, Miller and his team harvest the bone marrow from patients at the time of surgery with a small needle aspiration of bone marrow from the iliac crest. The marrow is spinned down and mixed with particulate collagen/glycosaminoglycan.

During the procedure, Miller and his team use an open arthrotomy, such as a plafondplasty, because it provides more exposure.

“More often, I have been going through a more open procedure because it is easier for me to obtain a nice contour to the collagen and there is not as much morbidity to the patient to do a small arthrotomy,” Miller said.

Next, the orthopedists add a drop of fibrin glue to the base of the osteochondral defect and pour stem cell-rich paste into the defect, over which they add two or three more drops of fibrin glue.

“Usually, that involves releasing the attraction on the joint and letting the corresponding tibial surface give you the appropriate contour to the fibrin glue topping,” Miller said.

The best candidates for stem cell-rich collagen paste are those with deeper defects, Miller added. Other inclusion criteria in the study were repeat microfractures or defects greater than 1 cm.

The researchers noted two patients who did not improve and needed DeNovo juvenile cartilage allografts.

Future plans

Miller and his colleagues continue to follow up on the patients who undergo the procedure. Their next step is to collect outcomes of their MRI findings to examine the “regeneration of appropriate cartilage signal,” Miller said.

They also plan to conduct a study comparing patients undergoing DeNovo vs. stem cell-rich collagen paste.

“We are still waiting to determine outcomes, but it is yet another option in treating osteochondral defects while preserving joint motion,” Miller said. “We think it is better than microfracture alone for larger defects.” – by Renee Blisard

Reference:

• Miller SD, Schon LC. A new technique: Arthroscopic filling of osteochondral defects with stem cell-rich collagen paste. Paper #7. Presented at the 2011 Annual Meeting of the American Orthopaedic Foot and Ankle Society. July 13-16. Keystone, Colo.

• Stuart D. Miller, MD, can be reached at Greater Chesapeake Orthopaedic Associates, LLC, 3333 North Calvert St., Suite 400, Baltimore, MD 21201; 410-554-6530; email: stubonedoc@aol.com.
• Disclosure: Miller is a consultant for Integra and Biomet.

As our society is increasingly more active, osteochondral injuries to the talus are becoming more commonly recognized causes of ankle pain and disability. Yet, the treatment of these lesions remains challenging because of the limited healing capacity of articular cartilage. The concern with traditional reparative techniques, including arthroscopic debridement, drilling and/or microfracture, is long-term fibrocartilage degradation. The use of stem cells has been proposed to help form organized hyaline cartilage in the repair of talar osteochondral lesions.

Drs. Miller and Schon present a novel technique of treating these lesions. The authors attempt to create a hyaline cartilage repair utilizing a paste of a concentrated stem cell-rich portion of autologous iliac crest bone marrow aspirate mixed with a flowable particulate collagen/glycosaminoglycan. Following debridement and microfracture through an arthroscopic or limited open approach, the paste is then applied with a fibrin glue covering and molded to the corresponding tibial surface.

As the authors note, patients with more defined and discrete articular surface lesions fare better. Further studies utilizing MRI and cartilage mapping should help to determine which lesions are most likely to benefit from this novel treatment. While early reports are encouraging, longer term follow-up is needed to confirm the durability and efficacy of this repair, and to evaluate the relative benefit of this technique compared to microfracture alone.

— Craig S. Radnay, MD
Insall Scott Kelly Institute for Orthopedics and Sports Medicine
New York City
Disclosure: Radnay is a consultant for Smith & Nephew and Wright Medical, and is on the speakers panel for Ortho McNeil Janssen.