Adding Stem Cells to Cartilage Repair: Not Helpful, But… // Athletes: Posterior Instability & RC Tears Do Better Than SLAP Tears and RC Issues // and More!

Adding Stem Cells to Cartilage Repair: Not Helpful, But…

She has commanded an Army image intelligence unit, become an orthopedic surgeon, and is Professor and Vice Chair of Research in the department of Orthopaedic Surgery at Stanford University. Now, Constance Chu, M.D., has led interesting new work published in The Journal of Bone and Joint Surgery investigating the role of mesenchymal stem cells in cartilage repair. This NIH-funded (National Institutes of Health) equine study looked at whether stem cells, specifically, bone-marrow-derived mesenchymal stem cells (BMDSMSCs), made a difference in cartilage repair. Dr. Chu told OTW, “Our aim was to determine if adding mesenchymal stem cells to an autologous platelet-enriched fibrin (APEF) scaffold enhances chondral repair more than APEF alone.”

“In this study, we culture expanded the appropriate bone marrow cell fraction and performed a randomized double blind study. One side of the horse got the scaffold alone while the other side got the same scaffold that contained the culture-expanded mesenchymal stem cells. Each surgeon—myself and veterinary surgeons Laurie Goodrich and Wayne McIlwraith from Colorado State University—were blinded to what we were putting in. One year later our team reassessed the horses via arthroscopy, histology, and quantitative MRI, as well as biomechanical analysis led by Robert Sah at the University of California San Diego. The result was that adding the stem cells didn’t improve the repairs by any of these parameters. Interestingly, the defects that received the stem cells didn’t do as well because we found ectopic bone formation in the cartilage repair from 4 out of 12 of these defects. This suggests that the implanted stem cells participated, but did not get the right signals, and formed bone instead of cartilage over time.”

“The exciting part about this in vivo data is that the stem cells likely survived and helped form part of the cartilage repair but were either less responsive to signals favoring cartilage or that the signals from the individual horse favored bone formation. Thus, the next steps are to figure out how to get the right signals at the right time into the repair site. This data also highlights that individual biology is variable and we can’t necessarily expect the same results in all patients.”

“When using biologics, I think it is critically important that physicians have a better understanding of blood products and stem cells in general, and that we are clear about what we are putting into patients. We’ve gone from platelet rich plasmas and concentrated bone marrow aspirates being the rage with athletes to high demand from middle aged to older individuals, most paying cash for these treatments. Do we really know that everyone’s blood is the same, or that we can isolate stem cells by processing tissues in the office or on the back table?”

“Minimally manipulated procedures such as bone marrow aspirate concentration do not yield appreciable quantities of stem cells. Mesenchymal stem cells are extremely rare and adherence to a culture dish is part of the basic procedure to isolate these cells. Culture-expansion of cells from a specific fraction of bone marrow is the bare minimum needed to yield anything close to the traditional definition of bone marrow derived mesenchymal stem cells. When using autologous blood or tissues, if the patient is older, unhealthy, or obese there may be higher levels of potentially negative factors such as inflammation and fewer anabolic agents such as growth factors and stem cells. To help advance the use of biologics in orthopedics, my group is currently working to determine the biologic repair potential of people as individuals.”

Athletes: Posterior Instability & RC Tears Do Better Than SLAP Tears and RC Issues

James P. Bradley, M.D., M.S. is a sports medicine specialist with Burke & Bradley Orthopedics at the University of Pittsburgh Medical Center. Dr. Bradley also is head orthopedic surgeon for the Pittsburgh Steelers and a past president of the National Football League Physicians Society. Commenting on his recent work, Dr. Bradley told OTW, “There is evidence that elite throwing athletes with SLAP (superior labrum anterior to posterior) tears and concomitant partial thickness rotator cuff [RC] tears have poor return to play results. We therefore conducted our own investigation, which included 25 of my elite throwing athletes with unidirectional posterior instability, some of whom had rotator cuff tears. Only those with significant partial thickness rotator cuff tears were included. Each of these throwing athletes had undergone arthroscopic capsulolabral repair, as well as pre-and postop patient evaluations, including return to play.”

“When we postoperatively compared patients with and without rotator cuff tears, those with rotator cuff pathology had poorer American Shoulder and Elbow Society (ASES) scores and more pain. Postoperative ASES scores in throwers without rotator cuff pathology were an average of 10 points higher than those without such pathology. Postoperative pain scores were higher in those with rotator cuff tears (1.1 versus 2.4). In addition, we noted that patients with concomitant rotator cuff tears had a feeling of instability preoperatively (8.3 versus 6.2) that disappeared after surgery. This allowed us to conclude that athletes with rotator cuff tears complained more about pain than about instability.”

“Return to play was the same for athletes in both groups (an average follow-up of three years), thus indicating that arthroscopic capsulolabral repair for posterior shoulder instability is successful in patients with significant rotator cuff fraying or tearing. So as opposed to those with SLAP tears and significant rotator cuff involvement, those with posterior instability and rotator cuff tears seem to fare better. It’s as if these patients are somehow insulated from that extra difficulty.”

“There are basically two types of posterior labral tears in throwing athletes. Type I is a pure posterior inferior labral tear at the glenoid labral junction. It typically propagates up to the equator of the glenoid. These can be with or without rotator cuff involvement. Our study involved these Type I tears. Type II tears start as a Type II B SLAP tear that propagates inferiorly, splitting the posterior labrum below the equator (with or without cuff issues). We feel that Type IIs are much more problematic in throwers.”

“My plan is to expand the scope of this work by doubling the number of study participants. Now that we know there is a difference between those with SLAP tears with concomitant rotator cuff problems and those with unidirectional posterior instability with labral rotator cuff tears, the goal is to find out why this difference exists.”

Neck Pain Not Always a Contraindication for Laminoplasty

It’s time to get the word out about laminoplasty, says Daniel Riew, M.D., director of Cervical Spine Surgery and co-director of the Orthopedic Spine Division at Columbia University Medical Center. Dr. Riew tells OTW, “Our study, recently published as the lead article in the Global Spine Journal, found that neck pain improved for many patients following laminoplasty. We examined the results from 34 patients who underwent this surgery, and who had a minimum one year follow-up. All completed pre-and postoperative NDI (Neck Disability Index) questionnaires.”

“It has always been conventional wisdom that neck pain gets worse after laminoplasty and therefore is a contraindication for the procedure. However, we found that the majority of people who had neck pain before surgery actually improved. Prior to surgery I told these patients, ’Your choice is between a multilevel fusion that leaves you with no motion…or we leave you with neck pain, but you undergo a motion sparing procedure.’ Their response was, ‘I can live with the neck pain. Let’s do the motion sparing procedure.’ We warned them that the pain was not going to get better, and could get worse…but in fact, it improved in the majority!”

So what were they doing right? “First of all, ” says Dr. Riew, “the neck ‘pain’ was probably nerve compression pain. All we had to do was take the pressure off the nerves. We are also very meticulous about preserving the integrity of the posterior cervical spine muscles. We open very carefully under microscope visualization, often using Metzenbaum scissors blunt dissection. We also close meticulously and in multiple layers. If you take great care with the dissection, the patient only loses a little blood and the muscles heal much better and continue to function normally.”

“Midline axial pain probably won’t improve. However, if the pain is in the upper trapezial area, then it will improve in a high percentage of cases.”

“Many surgeons in the U.S. don’t do laminoplasty either because it takes a long time, they don’t know how to do it or because it doesn’t reimburse well. The more we publicize the fact that it’s a great operation, the more doctors will take the trouble to learn it. I have written several instructional articles on it and the most recent one will be coming out in OKOJ (Orthopedic Knowledge Online Journal) soon. And any of my surgeon colleagues are welcome to come to The Spine Hospital to watch me perform this procedure. I do an average of one per week, at least. We will also be posting a video on the technique soon.”

Surgeons interested in watching Dr. Riew perform laminoplasty feel free to contact him at:

d.riew@columbia.edu