Laird Harrison

March 30, 2015

LAS VEGAS — The implantation of mesenchymal stem cells from iliac crest bone marrow improves the long-term durability of rotator cuff repairs, a new study shows.

"You increase the healing process, the quantity of fibrous tissue, and the rate of healing," Philippe Hernigou, MD, from the University of Paris, told Medscape Medical News.

The findings were presented here at the American Academy of Orthopaedic Surgeons (AAOS) 2015 Annual Meeting. First results were published in International Orthopaedics (2014;38:1811-1818).

More than 25% of rotator cuff repairs re-tear after surgery. This rate has not improved much, despite the advent of new surgical techniques. Mesenchymal stem cells have the potential to aid healing because they can differentiate into tenocytes, chondrocytes, and osteoblasts, and are the source of multiple growth factors.

Although researchers have been trying to find ways to harvest stem cells and implant them during joint surgery for more than 25 years, Dr Hernigou said he believes this is the first long-term controlled clinical trial of the procedure in rotator cuff repairs.

He and his colleagues harvested mesenchymal stem cells from the iliac crest of 45 patients. They then concentrated the stem cells and implanted them into the rotator cuffs of patients as an adjunct to single-row rotator cuff repair.

The number of cells available varied widely from patient to patient, but the average patient received 51,000 cells.

The rotator cuffs of the patients were monitored with iterative ultrasound every month for 24 months, and with MRI at 3 and 6 months and at 1, 2, and 10 years.

The 45 patients in a matched control group who underwent arthroscopic rotator cuff repair without stem cell implantation were similarly monitored.

After 6 months, repairs in all 45 patients in the stem cell group but in only 30 patients in the control group had healed (100% vs 67%).

Results at 10 Years

Ten years after the surgery, 39 repairs in the stem cell group and 20 in the control group were still intact (87% vs 40%; P < .05).

An analysis of the bone-marrow-derived grafts in the stem cell group revealed that the 39 patients with successful repairs had a mean of 4200 progenitor cells/cm³, whereas the six patients with failed repairs had a mean of 1500 progenitor cells/cm³.

"When you inject the cells into the tendon, you probably increase the fixation and shorten the healing time, but also you increase the strength in the tendon," Dr Hernigou explained. "You increase the number of cells, which means that you may protect the tendon for a longer period of time."

Orthopedists are very conservative in their training. We like to see stuff and feel it.

This study provides good evidence supporting mesenchymal stem cell implantation in rotator cuff surgery, said Raymond Rocco Monto, MD, from Nantucket Cottage Hospital in Massachusetts, who is a spokesperson for the AAOS.

"I think this is one of the better studies," he told Medscape Medical News. "And there are a lot of these studies in the pipeline, as people get over their reticence about using this. Orthopedists are very conservative in their training. We like to see stuff and feel it."

The procedure only takes about 15 minutes, and can be done with kits approved by the US Food and Drug Administration, which are available from a variety of manufacturers, Dr Rocco Monto reported.

Dr Hernigou has disclosed no relevant financial relationships. Dr Rocco Monto is a consultant for Exactech.

American Academy of Orthopaedic Surgeons (AAOS) 2015 Annual Meeting: Abstract 533. Presented March 26, 2015.


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