Aug. 26, 2023
Mayo Clinic is emerging as a leading force in a movement toward pediatric and adolescent hip preservation — a new field in the last 15 to 20 years — now with new expertise and technology available.
"Hip preservation is trying to modify the natural history and intervene to preserve a patient's native hip as long as possible," says Emmanouil Grigoriou, M.D., a pediatric orthopedic surgeon specializing in hip treatment for newborn to young adult patients at Mayo Clinic in Minnesota. "A hip replacement in a 10-year-old is different from that in a 70-year-old."
He explains that a hip replacement typically lasts 25 to 30 years, a span sufficient for an older adult. However, a young patient may require one or two revision surgeries in a lifetime after the primary hip replacement.
"It's problematic to have revision hip replacements," says Dr. Grigoriou. "Each revision is not as good as the previous one. Scar tissue is there, and the muscles are not the same as they were prior to the first replacement. So, the ability to give longevity to the native hip and for the patient to have one hip replacement in a lifetime means better quality of life. We are trying to not just preserve the hip of younger people but also make them feel better, especially alleviating pain and improving function."
Hip preservation for patients with DDH
One aspect of hip preservation involves treatment of developmental dysplasia of the hip (DDH), which usually is present at birth. DDH is the most common orthopedic disorder in newborns, says Dr. Grigoriou, and it affects 1% to 3% of infants, according to the Global Hip Dysplasia Registry. However, some patients with this condition do not consult a physician until years later. Patients who present with the condition may be 2 years old or 16- or 20-year-olds.
"Often, hip dysplasia is not recognized in early childhood," says Dr. Grigoriou. "It can be asymptomatic for years, with the patient remaining highly functional. The patient presents when joint damage and accompanying pain begin. Therefore, we don't have an age cutoff to be seen for DDH."
Risk factors for DDH include:
- Female sex.
- Firstborn child in a family.
- Family history of DDH.
- Breech presentation at birth.
The most crucial factors are the latter two. It is important for pediatricians to be aware of the risk factors so they can screen patients for DDH, says Dr. Grigoriou. He says current data indicate the condition has no relationship to any maternal behaviors and has no direct genetic correlation.
However, Dr. Grigoriou suspects a genetic connection is present but not yet identified.
Untreated, DDH can cause labral pathology, cartilage damage, and resulting pain and limited function. Over time, mechanical forces wear down surrounding cartilage, eventually leading to early-onset arthritis, which can result in the need for a hip replacement. Treatment prior to any cartilage damage in the region has better outcomes, says Dr. Grigoriou.
Dr. Grigoriou indicates that 95% of infants with DDH respond to treatment with a brace or harness alone. However, an orthopedic surgeon needs to operate if the hip does not respond.
Typically, the surgeon waits until the patient reaches 6 months of age, as anesthesia prior to this age has been associated with negative effects.
Use of perfusion ultrasound in DDH surgery
When Dr. Grigoriou started practice at Mayo Clinic in 2022, he introduced new technology for evaluation of blood flow to the hip: perfusion ultrasound. He explains that he performs this ultrasound before surgery to establish a baseline blood supply and then after hip surgery, checking for blood flow. This is especially important as DDH surgery can affect the blood supply of the hip.
When he views the ultrasound, he can see in real time the blood flow in the femoral head, which presents as microspheres. The patient's lungs eliminate these in minutes.
Dr. Grigoriou is a proponent of this technology because it is accurate, provides real-time information in the OR, is inexpensive to use and decreases return to surgery. Further, this technology gives the surgeon crucial information with minimal risk to the patient.
"I like to know there is blood supply to the femoral head, and I never leave the OR without knowing this," he says. "DDH surgery has a 20% risk of avascular necrosis, so this is critical."
Currently, only a few institutions in the U.S. offer perfusion ultrasound.
Hip preservation for pediatric patients with Perthes disease
Another new development in pediatric hip preservation at Mayo Clinic involves the inception of Perthes disease treatment with epiphyseal drilling and bone marrow aspirate concentrate (BMAC) injection. Previously, pediatric orthopedic surgeons attempted to treat Perthes disease — a rare, idiopathic femoral head necrosis — with surgery to change joint biomechanics. However, Dr. Grigoriou says over time, research in this arena identified Perthes as a biological condition requiring relevant treatment.
Therefore, to treat Perthes disease, Dr. Grigoriou begins with a perfusion MRI, observing any missing blood supply in the patient's femoral head. Then he drills the femoral head in points surrounding the dead area, prompting renewed blood supply. Next, he extracts the BMAC from the patient's pelvis. The concentrate is spun down into a concentrate at the time of surgery. The surgeon injects the concentrate, which contains cells promoting bone growth, into the drilled channels. The procedure is undertaken percutaneously.
Referral of patients with DDH or Perthes disease
Dr. Grigoriou recommends referring patients requiring surgical treatment for either DDH or Perthes disease to a facility such as Mayo Clinic in Minnesota. His reasons are as follows:
Training and expertise. He indicates that performing perfusion ultrasound, which he considers very important and the future of DDH surgery, requires special ultrasound technologist training. The pediatric orthopedic surgeon needs specialized training in perfusion ultrasound's timing and in interpretation of its results.
"These are extra skills one typically does not learn in a pediatric orthopedics fellowship," says Dr. Grigoriou. "Expertise is important to perform and, most importantly, interpret a perfusion ultrasound."
Dr. Grigoriou's training is rare: He completed a unique second fellowship in child and young adult hip preservation, available for one individual per year at each of three institutions offering this specialized fellowship.
Volume. While an orthopedic surgeon in the community may see a few patients with Perthes disease a year, many more patients with this condition present at Mayo Clinic. A higher volume of these patients leads to greater experience level, which Dr. Grigoriou says has been proved repeatedly to result in better outcomes in multiple types of surgery.
Resources and multidisciplinary approach. Mayo Clinic has invested in DDH and Perthes disease therapy resources. A multidisciplinary team manages the treatment, not just a solo orthopedic surgeon, adding expertise from many providers to address the patient's needs simultaneously from different medical backgrounds.
Dr. Grigoriou says he is confident in Mayo Clinic's prioritization of safety in these procedures and is excited about the institution's commitment to innovation.
For more information
Burden of disease. Global Hip Dysplasia Registry.
Refer a patient to Mayo Clinic.