Dr. Philippe Hernigou published a paper in 2014 entitled “Biological augmentation of rotator cuff repair with mesenchymal stem cells during arthroscopy improves healing and prevents further tears: a case-controlled study.” I selected this paper to start my review of Dr. Hernigou’s extensive clinical study series on BMC therapy for orthopedic pathologies in part because it has a 10-year follow up milestone, which is fairly rare in the orthopedic literature. It also illustrates a clinical format that I believe addresses at least one major concern for non-randomized clinical study formats—the placebo effect.
In the study on BMC augmentation after surgical repair of torn rotator cuff tendons, Dr. Hernigou reported on the MRI findings of tendon status at 10-years post-treatment. By focusing on an objective clinical outcome (i.e., MRI assessment of the treated tendon), a clinician can greatly diminish any impact of the dreaded placebo effect. The reason is that patients might say their repaired shoulder feels great in hopes of pleasing the physician, but MRI results, when read by a blinded reader (to reduce bias), can be used to make an objective assessment about whether or not the tendon is intact. In fact, this is the question that Dr. Hernigou assessed at 10-years—tendon status.
Another feature of a Level 1 clinical study is that the clinical investigators and study patients are blinded as to who received the placebo and who got the test treatment for the duration of the study. In this case, Dr. Hernigou chose a 10-year follow up period as the endpoint of the study. Who in their right mind would expect to keep a clinical study blinded for 10 years? At one point, an orthopedic surgeon challenged me over the results of the study by pointing out the study wasn’t blinded. I asked him if he had ever seen a Level 1 study that was blinded for 10 years. He indicated that it would be necessary only to blind it for a couple of years, but didn’t offer a good reason for why it was okay. Perhaps he thought the placebo effect disappears over time.
Having addressed some of the objections that are voiced by Level 1 study addicts, I will move on to cover the details of the study and results. Patients presented at the Henri Mondor Hospital (University of Paris, East, Creteil, France) for rotator cuff tears. They received a standard work up and if eligible, they were treated with the standard of care surgical procedure (a single row of sutures with anchor). The authors indicated that the non-BMC augmented standard of care was performed prior to 2000, but starting in 2000, patients received both the surgical repair and BMC augmentation. Consequently, a retrospective review of the patient records was conducted in which treated patients were enrolled in the study if they met the following major criteria:
- Had a tear of the supraspinatus tendon without involvement of other tendons.
- The tear was between 1.5 to 3.0 cm in length.
- The pathology was repairable by arthroscopic technique.
- There was no indication of degenerative arthritis of the glenohumeral joint.
- There was no biceps tenotomy or tenodesis.
As a consequence, a group of 45 patients was identified who met the criteria and had received a BMC-augmented surgical procedure. In addition to the criteria listed above, the demographics of the control group was matched to the patients in the BMC-treated group for the following:
- Tear size and location
- Dominant shoulder/pathologic shoulder
- Gender and age
For those of you interested in the details of the surgical repair, I refer you to the article. The article indicated that on average 150 mL of bone marrow was aspirated from the anterior iliac crest of the patient and concentrated. After the surgical procedure, which included abrading the cortical bone slightly (1-2 mm depth) to accommodate the reattached tendon (creating the “footprint” of the repair), 4 mL of BMC was injected into the tendon, while 8 mL was injected into the bone below the footprint.
I will finish my review of the Hernigou rotator cuff repair paper in the next post.