Orthopedic surgeon Debra Templeton, M.D., used to prefer external bracing of the three alternatives for correcting early onset Blount’s disease but not anymore.
These days, when Dr. Templeton and the other surgeons at Shriners Hospitals for Children — Northern California have a child with early-onset Blount’s disease, they tend to perform a guided-growth procedure, with the tension plate screwed across the physeal disk of the tibia on the lateral side of the bowlegged knee or knees.
“In this day and age, we are able to do growth modulation, with a little surgery where we put a device on the growth plate that almost serves as an internal brace,” said Dr. Templeton, a fellowship-trained, pediatric orthopedist who has served as a consultant editor for the Journal of Bone and Joint Surgery.
The orthopedic staff at the Northern California Shriners Hospital is so convinced of the advantages of the guided-growth procedure that they are drafting a research paper to document the hospital’s experience. The hospital has been doing the procedure for over 10 years and it now has accumulated a large series of cases – more than any published case series so far, Dr. Templeton mentioned in an interview.
“I always present the families that have Blount’s with two options, external bracing and guided-growth and it is incredibly rare in this day-and-age that I have a family who actually chooses the brace,” Dr. Templeton added.
Bracing is effective if done early, about 80% effective, according to Dr. Templeton. But it is very impractical for bilateral disease as the leg braces are rigid, making walking almost impossible for a toddler. Of all Blount’s cases, 70% are bilateral.
The third alternative for correcting tibia vara, osteotomy, is invasive and it requires a level of convalescence most young children have a hard time enduring.
When Dr. Templeton came to Shriners Hospitals for Children — Northern California, she remembers that a couple of surgeons were already performing guided-growth procedures. She had a hard time getting her mind around the concept at first. She wondered how restricting growth on the lateral side of the proximal tibia lead to catch up on the medial side if the very nature of the disease is that the medial side isn’t growing and is getting damaged.
“It was a technique I had never seen in my training or my fellowship for that particular problem,” she explained. “You know, any time there is something new, you kind of want to see the results from other people before you start doing it.”
But the other surgeons were staunch believers and then she had a very obese patient, with bilateral disease, which ruled out the feasibility of bracing. She gave the titanium plate a try and she has been a convert ever since.
“The only other option at that point would have been an osteotomy, which is a very morbid procedure,” Dr. Templeton said, discussing the case. “So, I was like, I really don’t have anything to lose. Let’s give it a try, and it worked. So, after that, I kind of became a believer.”
As for how it works, Dr. Templeton notes only that when you watch the process, it seems that the catch-up gains momentum as it progresses as the pressure on the medial condyle apparently lessens as the two sides even up.
“Apparently it grows enough that you can get correction,” said Dr. Templeton. “And then as it starts to correct, you take pressure off that medial growth plate, which allows it to grow even more and become healthy.”
Not everyone is so totally convinced, however, and that is where the Northern California Shriners Hospital paper might come in to play.
A paper from the Shriners Hospitals for Children — Houston published in 2012 on 12 cases of infantile Blount’s disease reported an 89% success rate at producing full mechanical axis normalization. There was some recurrence after correction for a few patients but generally the success rate reported was considered excellent (3).
However, a review article published more recently, with bigger numbers, suggested that almost half of those treated with a guided-growth strategy needed a subsequent surgery (4). The review authors tried to look at whether they could determine whether the plate was better than the staples and whether a procedure done when a child was young had better results than one done when a child was older and even adolescent. Their investigation was unable to show a statistically significant difference among any of those factors.
Dr. Templeton said that recurrence does sometimes occur when the corrective plate is removed, but that is just the nature of the condition and she has only had one case of a patient who needed an osteotomy for persistent varus. Normally, when there is a recurrence, she does the procedure again and there is correction again.
“It is important for the families to understand that these kids often need a series of operations to maintain lower extremity alignment
“It is important for the families to understand that these kids often need a series of operations to maintain lower extremity alignment,” she said. “Often times, the varus will correct so we have to remove the plates. Then the varus can recur and we have to reinsert the plates. I counsel families that this management technique often involves several low risk outpatient procedures and is not a onetime surgery. The goal is to make sure the leg(s) are straight at skeletal maturity.”
1.) J Bone Joint Surg 1949;31:464-78.
2.) J Pediatr Orthop 2007;27:253-59.
3.) J Pediatr Orthop 2012;32:29-34.
4.) J Pediatr Orthop B 2020;29:65–72.