Stem Cells + HA New Injection for Knees?; Fracture Repair: Don’t Aim for Perfection!…and more…
Elizabeth Hofheinz, M.P.H., M.Ed. • Wed, March 6th, 2013
Mesenchymal Stem Cells + HA for Knee Repair
What do you get when you mix hyaluronic acid (HA) with a certain type of stem cell? A solution that might potentiate the benefits of microfracture, says Brian Cole M.D., a sports medicine and cartilage restoration orthopedic surgeon at Midwest Orthopaedics at Rush in Chicago. He tells OTW, “We have enrolled our first patient in a trial that utilizes lyophilized hyaluronic acid and adult mesenchymal stem cells from umbilical cord donors to augment microfracture in the treatment of a localized cartilage defect of the knee. Our team, which includes Andreas Gomoll, M.D. of Brigham and Women's Hospital, is assessing the safety and efficacy of stem cells from umbilical cord blood—mixed with hyaluronic acid—as an adjunct to microfracture surgery. This is a two-year, Phase I/IIa study that should pave the way for a pivotal study in approximately two years. Although our goal is to enroll a total of 12 participants (18 years and older), like in any cartilage trial, the number of patients with isolated defects is relatively small; they can’t have any significant comorbidities such as apposing surface arthritis, malalignment or meniscal deficiency. Specifically, this treatment is meant for individuals who have localized cartilage damage and will not include patients who have been told they should have knee replacement surgery or who have bone on bone arthritis.”
BMP: Not a Cancer Risk?
Now and five years from now we will most likely still be using BMP (bone morphogenic protein), says one spine surgeon. Why? Because we need it. Andrew Hecht, M.D. is Chief of Spine Surgery and an assistant professor of orthopedics and assistant professor of neurosurgery at Mount Sinai; he also sits on the NFL brain and spine committee. “Even in the setting of MI techniques BMP is an important tool for spine surgeons. There remains a lot of concern about the right dose and carrier for various surgeries, but I think we will get better at delivering BMP and thus will be able to use it in more parts of the spine. We use it sparingly in challenging cases, such as when someone is at risk for nonunion. I know that my colleagues around the country continue to weigh the pro and cons of BMP, but I have found it to be very effective. We have had minimal complications, likely because we have been judicious in its use and take steps to reduce risks of complications such as the use of steroids when using it in the cervical spine.”
“Last year our team at Mt. Sinai presented a paper at the North American Spine Society meeting about the risk of cancer from BMP. In our research—a meta analysis—we found no cases where BMP took normal cells and transformed them into cancer cells. Additionally, Dr. Paul Anderson did a review of a national inpatient sample and did not find any evidence of increased cancer in patients who had received BMP. The problem is that we don’t know its effect on existing cancers. BMP has suppressive effects on some types of cancer cells and others it may be more stimulating…and there are some concerns that when used in high doses BMP can stimulate the growth of cancer cells.”
Fracture Repair: Don’t Aim for Perfection?
Concerned that if you don’t fix that fracture flawlessly you may leave the patient open for arthritis? Think again. Donald D. Anderson, Ph.D. is an associate professor in the department of orthopaedics and rehabilitation at the University of Iowa (UI). He tells OTW about his work in the UI Orthopaedic Biomechanics Laboratory: “Most surgeons believe that when you fix an articular fracture that you must do it perfectly. This is because research over the years has shown that irregularity in the joint surface leads to elevated joint contact stress, which in turn leads to arthritis. So surgeons are taking this approach to restore function. While this elevated joint contact stress is a risk factor for arthritis, there has not been a sound way of assessing it. There is some indication in the literature and in clinical experience that you don’t have to get it perfect, but in the absence of any way to tell what to do surgeons are a bit lost.”
“This uncertainty leads to wider exposures, which leaves patients more vulnerable to infection and other operative complications. Our research has shown how a CT scan after an ankle fracture repair can be used to create a computer model to predict the contact stress. By following a cohort of patients, we have shown that it’s basically a threshold effect with respect to elevated contact stress. If the CT scan shows exposure to contact stress below a certain level then it doesn’t matter—the patient won’t develop arthritis. We began with a small number of patients at Iowa, but we are extending that to 150 patients from a number of institutions across the country. Let’s say this holds up…then we will have a good idea of the threshold above which people develop arthritis. This may mean that surgeons can decide intra-operatively if they have done a good enough job based on such computer modeling. Surgeons could use deduced fragment poses from fluoroscopic images, correlated with pre-operative CT models, to make contact stress assessments in the operating room.”
Too Many Spine Surgeons Rely on Outdated Data
It’s time for more clarity when it comes to spinal fusion. Doctor A in Pittsburgh does one thing, Dr. B in Tallahassee does another. Dan Riew, M.D. is The Mildred B. Simon Distinguished Professor of Orthopedics and Professor of Neurosurgery at the Washington University School of Medicine in St. Louis. He reveals details about his latest research: “We are working on how to diagnose fusion properly because there are no accepted standards for how to diagnose fusion with plain X-rays. Some doctors use flexion or extension, some look for less than 2 mm of motion, while others look for less than 1 mm. Some physicians aren’t even bothering to get any kind of flexion extension views. We know, however, that if you want to have results that are highly sensitive and accurate you should look for less than 1 mm of motion—and you must have greater than 4 mm at an unfused level. That way you are sure that the patient flexed and extended adequately.”
“When we compared CT Scans with intraoperative exploration plus plain X-rays we found that plain X-rays can be nearly as good as CT Scans. But to get that good you must have criteria of less than 1 mm of motion on a magnified plain X-ray. The clinical implications are such that when patients complain about pain after surgery they are sometimes told, ‘There is nothing wrong with you. The fusion looks solid.’ But the fact is that a lot of those patients can be helped by a repair of the nonunion. Also, a lot of studies purport to have a 100% fusion rate based on the use of outdated criteria. Unfortunately, I think that some of my colleagues still think these criteria are valid.”
Christopher Wahl, M.D. New Chief at UC San Diego
The new head of sports medicine at the University of California, San Diego Health System, Dr. Christopher Wahl, is known for treating complex, high-energy traumatic sports injuries. Dr. Wahl, who served as associate professor and team physician for the University of Washington in Seattle, was the orthopedic surgeon for the Huskies’ athletic teams, including football, men’s basketball, volleyball, softball, gymnastics and tennis.
Dr. Wahl, who attended medical school and completed his residency training at Yale University, plans to focus his practice on cartilage restoration and transplantation, repair of the knee and shoulder, rotator cuff pathology, shoulder stabilization and treatment of fractures. Dr. Wahl completed a sports medicine and shoulder surgery fellowship at the Hospital for Special Surgery in New York. He continued his professional education studying trauma surgery in Germany and Switzerland before starting his clinical practice. In 2011, Wahl was awarded the American Orthopedic Society Traveling Sports Medicine Fellowship and traveled throughout the countries of South America to visit sports medicine clinics, hospitals and institutes.
Dr. Wahl has lectured and published extensively on sports medicine and surgery, including: the anatomic factors predisposing to anterior cruciate ligament tears, the treatment of recurrent shoulder dislocations associated with bone loss and the diagnosis and management of knee dislocations and multiple-ligament knee injuries. In addition, he has developed several innovative surgical techniques for the treatment of cartilage repair, shoulder instability and revision surgery for failed procedures.