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What are the limitations with Perthes and weight bearing?

If your child is diagnosed with Perthes Disease, it is both important and challenging to encourage limited weight bearing for a certain period of time. Although complete compliance with most of the children dealing with this issue is difficult, it is essential for parents to be aware of the benefits limited weight bearing has with the overall healing process. During certain phases of the disease and after surgery, some level of activity modification and protected weight bearing can be of the utmost importance and can determine the long-term health of the hip.

Restricted weight bearing is usually required during the early stages of Perthes because fragmentation and collapse render the femoral head soft and susceptible to deformation by excessive stress. Additionally, restricted weight bearing can be required following surgery to allow appropriate healing and recovery. Depending on the patient, the length of time needed for limited wear bearing can vary. Currently, the International Perthes Study Group (IPSG) is researching the difference between six weeks versus six months of non-weight bearing.

It takes a lot of patience, understanding, and creativity to get through these difficult periods of Perthes. Promotion of non-impact activities such as biking and swimming can be used as good alternatives to more strenuous sports. The members of IPSG understand the importance of increased support and guidance during the difficult part of the disease. Your physician and their team are here for you to do all we can to help our patients and their families.

Michele Rector: A Perthes Hero

Michele Rector is an inspiration. Her son was diagnosed with Perthes and she is dedicated to raising awareness and funds for research through running. Learn more about her journey and locations of where she will be running! #PerthesHero 

What is "Run 50 by 60 for Perthes"? Run 50 by 60 for Perthes is my mission to run 50 states by my 60th birthday - Sept. 11 2022 - in order to bring attention and funding to the International Perthes Study Group

What was your motivation to start this initiative? After completing three marathons in three different states in 2016, I decided I wanted to run all 50 states. But, it seemed selfish and a wasted effort to do it just for myself. So, I decided I should run for a reason…and right away I thought that reason should be Perthes! When my son was in the middle of the disease, I wished I had the time to do something BIG to draw attention to it and raise money for research, but it was just not the right season for our family. Now I finally had the time and the ability!

What is your ultimate goal for this program? Well, my ultimate goal is to raise money to fund research so that the cause of Perthes can finally be identified - and prevented! Of course, there are other goals. I would like to raise awareness so that people know what it is and families don’t feel so alone. I want more physicians to know about the disease in order to provide their patients with effective treatment and can direct them to helpful resources, like IPSG. I would like to encourage families who are in the middle of the disease a voice, a place to relate, and HOPE! It DOES get better and when you’re in the middle of it there’s a lot of bad news - x-ray after x-ray brings worse news. Sometimes it can seem very hopeless. I want kids with Perthes to see my son who is on the other side and is doing GREAT!

How are you connected to Perthes disease? My son, Graham, was diagnosed with Perthes just before his 8th birthday while we were living in Hong Kong. It was a tough three years for him and, by extension, us. He was on crutches for over two years with about three months in an A-brace AND crutches. He couldn’t do the activities that his brother and friends were doing. He finally had a femoral osteotomy and was in a wheelchair for six weeks, then crutches another three months

When he was going through it, I was frustrated with the huge lack of information on the CAUSE. It seemed like gains were being made with so many other diseases, but the cause and treatment of Perthes remained essentially the same since its discovery over 100 years ago. I thought that if I could help bring funding to the research, it could finally be prevented, cured, anything better than just waiting for it to be over. But, like most families with young children, especially those with Perthes, I just didn’t have the time or resources to do anything besides take care of my family.

Michele's race schedule for the rest of the year into 2018:

June 17 - Grandma’s Marathon Duluth MN

July 9 - Missoula Marathon Missoula MT

August 27 - Nebraska State Fair Marathon Grand Island NE

Sept 10 - Sioux Falls Marathon Sioux Falls SD

Oct - TBD

Nov 5 - NYC Marathon - I am running with Team TCS (the NYC Sponsor) as a sponsored runner!

Dec 10 - Mississippi Gulf Coast Marathon Pass Christian to Biloxi MS

Jan. 7 2018 - Disney World Marathon Orlando FL



Why is Participating in Research Important?

Perthes disease is a childhood hip disorderthat requires extensive research to find the cause and a cure. Your child’s participation is important to provide answers to the many questions people have about this mysterious condition.Since this disease varies with age at onset and the stage at which a child goes to a specialist, various research studies that focus on the variety of the condition is crucial to fully understanding every aspect.

Research is the engine that drives the discovery of medical knowledge. Gaining knowledgeof the disease in turnenhances an expert’s ability to better treat patients. The International Perthes Study Group (IPSG) brings pediatric orthopedic specialists from around the world to combine their efforts and collaborateon research questions about treating patients diagnosed with this disease.IPSG is an important component to the Perthes community and the participation from patients is pivotal to the group’s success.

Parents of patients diagnosed with Perthes want to know how they can help. The answer is research. Research allows doctors to gather medical information about different patients and their response to treatment over time in order to find trends. The ultimate goal of research is to provide a recommendation on how to treat each child based on medical evidence supported by research findings. Since IPSG’s inception in 2012, the research group is working on several important questions.  These questions include the following:

  1. Can advanced MRI, called a perfusion MRI, predict the outcome of Perthes in the early stage of the disease?
  2. For children with onset of Perthes at ages between 6 to 8, do they have better results with operative treatment compared to non-operative treatment?
  3. For children with onset of Perthes at agesbetween 8 and 11, how long should they stay off the affected leg after surgery? 


Below is what we are learning:

  • Pain is a significant factor present among patients in the early stages of Perthes, sometimes severe enough to interfere with school attendance.
  • Obesity and high BMI is a prevalent concern among the LCPD cohort
  • Based on a recent assessment, history of ADHD or smoke exposure are two factors not observed as often in the Perthes research population as
  • expected.
  • A health questionnaire called PROMIS, has been found to be a useful and valid tool for measuring quality of life in patients with Perthes disease.
  • The Waldenstrom classification system, an X-ray measurement to determine the stage of Perthes disease, has unified how doctors read hip X-rays in
  • the population.


Want to learn more about how you can get involved? Please email with your questions and to find IPSG members near you.  


IPSG Members Present at the 2017 EPOSNA Combined Meeting

Last week, medical professionals and researchers from around the world attended the 2017 EPOSNA meeting in Barcelona, Spain. The combined meeting brought together two established pediatric orthopedics societies, POSNA (Pediatric Orthopaedic Society of North America) and EPOS (European Pediatric Orthopaedi Society) to discuss research and education. 

EPOSNA 2017 was the largest pediatric orthopedic scientific meeting with over 1,300 abstracts submitted, and only 200 podium and 200 posters accepted for presentation. The four-day meeting included research projects on topics such as hip, spine, trauma, lower and upper extremity, sports medicine, and various basic science areas. Members from IPSG had a strong showing at the international meeting, including presentations and posters on various aspects of perthes. A few of the perthes podium and poster presentations at the 2017 EPOSNA, included:

  • Dynamic Deformation of the Femoral Head Occurs on Weight Bearing in Early Fragmentation of Perthes Disease;Alexander Aarvold, FRCS (Ortho); Angela Eugenio; Harpreet Chhina, MSc; Chris Reilly, MD; David Wilson; Kishore Mulpuri, MD; Anthony Cooper, FRCS (Ortho) British Columbia Children’s Hospital, Vancouver, British Columbia, Canada


  • Modified Waldenstrom Classification Less Than II-B Associated with Better Surgical Results in Severe Legg-Calve-Perthes Disease; Charles T. Mehlman, DO, MPH; Ayesha Yahya; Junichi Tamai, MD; Emily Eismann, MS; Alvin Crawford, MD Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States


  • Secondary Spherical Remodeling from the Healed Stage to Skeletal Maturity in Legg-Calvé_Perthes Disease Treated with Salter Innominate Osteotomy; Hiroshi Kaneko, MD, PhD; Hiroshi Kitoh, MD; Masaki Matsushita, MD; Hiroki Furuhashi, MD; Tadashi Hattori Nagoya University School of Medicine, Nagoya, Aichi, Japan


  • Operative Treatment for Perthes Disease Yields Better Outcomes than Non-operative Treatment at 20 Year Follow-up;Daniel J. Sucato, MD, MS; Adriana De La Rocha, PhD; Lauren Paraison, BA; Harry Kim, MD; John Anthony Herring, MD; Texas Scottish Rite Hospital for Children, Dallas, Texas, United States


  • Hip Containment Surgery after Arthrodiastasis in Severe Perthes‘ Disease; Sandra Breyer, MD; Michael Novak, MD; Martin Rupprecht; Kornelia Babin; Ralf Stuecker Altonaer Children’s Hospital, Hamburg, Germany


  • Externally Validating Quantitative Measures of Femoral Head Shape in Perthes’ Disease; Manish Kiran; Weisang Luo, MBChB; POTS Collaborators; Daniel Perry, Alder Hey Children’s Hospital, Liverpool, United Kingdom


  • Radiographic Outcomes in Legg-Calve-Perthes Disease after Petrie Casting; Henry Iwinski, MD; Charles Bishop, MD; Jaylynn Hill; Donna Jean Oeffinger, PhD; Ryan D. Muchow, MD; Vishwas Talwalkar, MD; Janet Walker, MD; Lexington Shriners Hospital for Children, Lexington, Kentucky, United States


  • Triple Pelvic Osteotomy in Patients with Severely Affected Legg-Calvé-Perthes Disease (LCPD); Thomas Wirth; Oliver Eberhardt; Francisco Fernandez Olgahospital, Klinikum Stuttgart, Germany


Members, who traveled to Spain, also attended an IPSG meeting. IPSG Chair, Harry Kim, M.D., organized the meeting to allow members to discuss progress on various studies and touch base on the upcoming annual IPSG meeting in October.

Interested in learning more about the IPSG studies? Email to learn more or like our Facebook page.


IPSG Member, Dr. Mehlman: Learning More About Why There are Varied Treatment Options for Perthes


Variation in the treatment of Perthes disease can certainly be confusing if not maddening to parents seeking answers.Unfortunately it seems like we still have more questions than answers regarding this disease. Be that as it may, the question: “Why are there such varied treatments of Perthes disease among doctors?” is an immensely valid one.

Treatment variation can come from several sources. One is the disease itself. Perthes does not affect every child in exactly the same way, so treatment must be tailored to the needs of the individual child. Another source of variation is individual training and experience of the pediatric orthopaedic surgeon. Not all doctors receive exactly the same teaching and training. 

At some point in the future biological treatments and specialized medications may allow us to treat Perthes at its earliest stages.Until then we are simply reacting to relatively established Perthes. The treatment principles are well known and nearly universally accepted: containment and range-of-motion. Containment means doing the best job we can keeping the femoral head in the socket and range-of-motion means optimizing the movement of the hip (both achieved either surgically or non-surgically).

Learn more from publications on Perthes:


Balasa VV, Gruppo RA, Glueck CJ, Wang P, Roy DR, Wall EJ, Mehlman CT, Crawford AH. Legg-Calve-Perthes disease and thrombophilia. J Bone Joint Surg-Am 2004;86:2642-2647.


Bowen JR, Guille JT, Jeong C, Worananarat P, Oh CW, Rodriguez A, Holmes L, Rogers KJ. Labral support shelf arthroplasty for containment in early stages of Legg-Calve-Perthes disease. J Pediatr Orthop 2011 (2 Suppl);31:S206-S211.




Nguyen NT, Klein G, Doghey G, McCourt JB, Mehlman CT. Operative versus nonoperative treatment for Legg-Calve-Perthes disease: a meta-analysis. J Pediatr Orthop 2012;32:697-705.



A Glossary for Perthes Disease

Acetabulum: The socket part of the hip joint.

Arthrogram: Anarthrogram is a radiology procedure in which special X-ray medicine is placed into the hip joint. This X-ray exam shows and evaluates the shape of the ball part of hip joint (femoral head). It also assesses whether the femoral head is covered (contained) by the socket part of the hip joint (acetabulum). Most patients tolerate this procedure very well. A nurse will monitor your child for pain management needs. Sedation is available if needed.

Femoral head: The ball part of the hip joint.

Leg length discrepancy: A difference in length between the two legs.In some patients with Perthes disease, the affected leg can be shorter.

Necrosis: Refers to cell death in general; osteonecrosis refers to bone cell death.

Ossification:This is a process of new bone formation.

Range of motion: Movement of a joint in all its directions. For example, hip abduction is to move the leg out, away from the body.

Referred pain: This is pain starting from somewhere else but is perceived to begin at that site. In Perthes disease, some patients complain of knee or thigh pain instead of hip pain.

Resorption: Removal of dead bone by the body.

Tenotomy: Surgically lengthening or releasing a tendon that is tight to improve hip joint motion. In some patients with Perthes disease, hip adductors or muscles that bring the leg in (adduction), can get tight and prebent the leg from being abducted (bring the leg out). If the abduction movement is lost, the hip adductors may need a tenotomy. 



Perthes Heroes: Earl Cole

At what age were you diagnosed with Perthes? Age 7 

What was your treatment plan? Non-weight bearing (no surgery), leg brace, leg casts, wheelchair, crutches, etc.

How long were you inactive? Until the age of 13, so around 6 years of being inactive.

Once you were healed, what was it like getting back into activities? Perthes doesn't work like that. I was never healed, but my body did get stronger as I grew older. I was eventually cleared for normal physical activities (run, jump, play), even high school sports (at age 17). However, there would be some pain afterwards with strenuous activity. I was able to have a very fun, athletic and active life as a young adult.

You won Survivor:Figi, what was it like accomplishing something like that after overcoming Perthes? It was great to win Survivor Fiji. I was glad to make my family proud. I was also happy to have an international platform to use in order to help raise awareness about Perthes disease. Being a role model for kids and families dealing with Perthes, is something that I will always cherish. I was also able to establish the Perthes Kids Foundation with my prize money.

What is your advice to kids diagnosed with Perthes? My advice is to always be you, no matter what. It's OK to be considered different or not like every other kid. That is what makes a Perthes kid special. Embrace it. Be different. Be unique. Just be you, no matter what that looks like to everybody else. The experience that you learn from dealing with Perthes will help build the strength, patience, character and empathy you will need to be an extraordinary adult.

What was more difficult: healing from Perthes or winning Survivor? Healing from Perthes has been much more difficult than winning Survivor. Survivor only lasted 39 days, Perthes has been pretty much my whole life. Once the opportunity came for me to be on Survivor... my previous Perthes experience made being a Survivor, seem easy! At this point in my life (my 40's), the toll of sports and Perthes had finally caught up with me in the form of arthritis of the hip, causing chronic pain. I had a full hip replacement this year, where I am officially Perthes pain-free! Best decision I ever made. I continue to be a Survivor of Perthes and on TV!


Tips on How to Deal with Pain During the Fragmentation Stage of Perthes Disease

Pain is one of the most common presenting complaints in early Legg-Calve-Perthes disease (along with limp). Pain typically is felt in the groin, side of the hip area, thigh, or even the knee. In the early stages of LCPD pain is typically caused by synovitis (inflammation of the joint lining), extra fluid in the joint, and/or muscle spasm. Pain severity can be quite significant but usually waxes and wanes and rarely is it so bad that it prevents walking altogether. 

After the initial necrosis stage, the hip enters the fragmentation stage. It is during this stage that the hip is most at risk for deforming mechanically. Pain tends to continue through this phase and may be the result of the actual fragmentation process or secondary to synovitis or muscle spasm. As the ball of the hip starts to reform, pain typically starts to resolve. In fact, when x-rays are somewhat inconclusive, resolution in symptoms can help identify the end of fragmentation. While symptoms usually improve during the healing phase, some patients may still experience discomfort from muscle fatigue on the side of their hip or from an abnormally shaped femoral head. Depending on the severity of the residual deformity, patients may or may not begin to develop symptoms later in adolescence or young adulthood after a period of being symptom-free.

While parents of children with Perthes are understandably concerned about their child’s pain, treatment focuses primarily on minimizing the amount of collapse and the degree of femoral head deformity, as this has the largest effect on the long-term outcome of the hip joint. During early stages, anti-inflammatory medications such as ibuprofen can be helpful to manage the symptoms. A period of crutch use and activity modifications (avoiding sports etc) can also help reduce the pain. As mentioned previously, symptoms usually get better after the fragmentation phase, which is why doctors are most concerned with preserving the shape of the hip. Surgical options for hip preservation exist for older adolescents and adults who may begin to have symptoms from their residual deformity.


Building and Sharing Knowledge: The Importance of Medical Professionals Attending Conferences

The American Academy of Orthopaedic Surgeons (AAOS) is a group comprised of orthopedic surgeons and allied health professionals. The Academy serves over 39,000 members worldwide and is the world’s largest medical association. Surgeons and other medical professionals gather annually for a five-day conference for members to collaborate, educate, and present on various topics in orthopedics.

AAOS is just one of the many conferences that medical professionals attend throughout the year. These meetings serve as an arena for those in the medical field to further their education by learning from fellow doctors, researchers, allied health professionals, etc. Attending these conferences is a key component to innovation and is necessary to enhance the treatment of patients.

International Perthes Study Group (IPSG) chair and Director of Research at Texas Scottish Rite Hospital for Children, Harry Kim, M.D., is presenting at the AAOS Specialty Day. This is a segment of the conference that allows members to have breakout sessions with a more distinct group of their interest/specialty. 

With the purpose of educating fellow pediatric medical professionals, Dr. Kim’s presentation will focus on the treatment of Perthes, “Bringing Science to Patients, Is it Time for a New Treatment Algorithm for Perthes?”  Dr. Kim, along with other members of IPSG, attend AAOS in order to share and learn more in groundbreaking research to bring better care to each of their patients.

Q & A for Perthes Disease

What causes Perthes disease?

The cause is unknown and the disease is not inherited in most patients. A very small number of patients have another family member with Perthes.

Should I expect a lot of complaints of pain?

Pain generally suggests that there is hip joint inflammation, which can be caused by too much activity. The amount of pain experienced by a child with Perthes disease varies from patient to patient. Some patients complain of activity-related pain or night pain only. Your child may complain of groin, thigh or knee pain. They may have restricted movement and a mild limp. You and your child’s doctor will discuss how to manage pain.

What is the time frame of Perthes?

Perthes disease has four stages. In general, it may take three to five years for a patient to go from the initial stage to the healed stage of the disease. The length of each stage can vary.

What activities can my child do?

Your child’s doctor will help you determine the activities that are safe. The answer will depend on the stage of the disease, symptoms and hip joint stiffness.

What are long-term effects of Perthes disease?

Most children have occasional periods of increased pain and stiffness for six months to two years. Most children will return to typical activities and sports once healed. However, some children may be at risk for developing arthritis as adults. Children’s hips that grow back irregularly will have more symptoms, such as pain and hip stiffness, and a greater risk of arthritis later in life.

Will my child be able to participate in physical activities?

Even with a deformed femoral head, most patients can perform daily activities and sports’ activities once the hip has healed.

Is hip replacement an option?

Hip replacement is not a surgery for children. Only when a patient develops painful degenerative arthritis later in adulthood is the surgery recommended.


Perthes Patient Story: Jasta


Meet Jasta! 

Jasta is a Perthes patient of IPSG Chairman, Dr. Harry Kim. 

When Jasta was in Kindergarten, he was diagnosed with Perthes. Today, he is in the 2nd grade and is currently in the regrowth stage of the disease. Although his activies have to be limited, he understands and is hopeful that one day he will be able to run around again. 

Getting to know Jasta

Favorite activity: playing video games

In your own words, what is Perthes disease? Perthes disease is when the blood stops flowing to your hip.

Advice for other kids with Perthes: To play video games, for fun and to play other games with your family. When you get better, you will be able to run around again! 


Dr. Sankar - CHOP

Wudbhav N. Sankar, MD

Dr. Sankar is the director of the Young Adult Hip Preservation Program at Children’s Hospital of Philadelphia (CHOP). Learn more about Dr. Sankar here. 


Medical: MD – University of Pennsylvania School of Medicine, Philadelphia, PA

Internship: Surgery – Hospital of the University of Pennsylvania, Philadelphia, PA

Residency: Orthopedic Surgery – Hospital of the University of Pennsylvania, Philadelphia, PA


  • Adolescent Hip Surgery, Boston Children’s Hospital, Boston, MA
  • Pediatric Orthopedic Surgery, Shriners Hospitals for Children, Los Angeles, CA
  • Pediatric Orthopedic Surgery, Children’s Hospital Los Angeles, Los Angeles, CA


Undergraduate: BS in Materials Science and Engineering – Cornell University, Ithaca, NY


Perfusion MRIs: Recent research showing the purpose with Perthes Disease

A recent study conducted by Dr. Harry Kim, Chairman of IPSG and staff doctors and researchersat Texas Scottish Rite Hospital, looked at the use of an advancedMRI called perfusion MRI, a new diagnostic imaging testtodetermine revascularization of femoral heads of patients with Perthes disease. Revascularization is the return of blood flow to the femoral head (the ballof the hipjoint) that has suffered from stoppage of blood supply. One of the most important components in the healing of Perthes is the return of blood flow to necrotic bone. Since this is such an essential part of healing, researchers wanted to better understand the things that affect the rate and quality of revascularization.

The study included29 patients with an average age of 8 years who were in the first two stages of Perthes, so called Walsenstrom stage 1 or 2.

The 29 patients included in this study had two or more perfusion MRIs during the study period. One important finding from the study was that the amount of blood flow absent or present in the femoral head differed from one patient to another, along with the speed of the return of blood flow over time. By following these patients with MRIs, the researchers found the return of blood flow to the affected femoral head increased over time and the pattern of blood flow return was somewhat of a horseshoe pattern. The revascularization started from peripheral regions(posterior, lateral, and medial aspects) of the femoral head and merged toward the center over a period of 1 year or more.   

Currently, there is limited research about the revascularization process that takes place in the necrotic femoral heads of patients with Perthes. This study is important as it showed that the return of blood flow in Perthes increases over time, but the rate of return can vary a lot from one patient to another. This finding emphasizes the need to individualize the treatment plan of each patient.


Spica Casting 101

What is a spica cast?

A type of cast used to prevent movement and alleviate pressure on the hip joint. It allows the femoral head to heal without any disturbances. A spica cast is applied to a child after containment surgery, in which the patient could be in the cast for four to six weeks.

Where is a spice cast placed on the body?

A spica cast is placed around the waist and hips. It can extend up toward the ribs, as well as down either leg to the ankle.

What to wear when in a spica cast?

  • Button down or large t-shirts
  • Baggy pants or shorts – pants that button up the side
  • Dress or skirt


What to know about cast care?

  • Use a slightly damp cloth with soap to remove dirt – allow cast to air dry
  • Sponge bath only – use towels to protect cast
  • If the cast begins to smell bad, rub a small amount of dry baking soda into the dirty areas


Car seats and Spica Casts

It is usually possible for the child to fit into their regular car seat while in their spica cast. However, it is recommended that you bring the car seat up to the inpatient floor to make sure it will fit while the spica cast is on. If the child cannot fit into their regular car seat, you might need to purchase a larger (toddler size) car seat.



Perthes and Obesity: A New Topic of Discussion

The uncertainty of Perthes continues to be an ongoing story. As new research is published, another piece of the puzzle becomes available to figure out the many facets to the disease. Recently, a research study conducted by IPSG members at Texas Scottish Rite Hospital for Children, doctors Kim and Herring, along with other researchers, showed a high prevalence of obesity in patients with Perthes.  This perspective of Perthes is now a topic of discussion as Perthes disease was once thought to affect thin, active children, especially boys.  

This study is new and interesting as it is one of the first of its kind to look at the common presence of obesity in children with Perthes, its effect on treatment, and how socioeconomic status correlates. The study specifically examined 150 patients with Perthes disease between 2009 and 2014, which coincides with the current obesity epidemic in the United States. The patients were grouped based on age and body mass index (BMI) using the Center of Disease Control (CDC) pediatric BMI calculator. The date range was selected in order to be consistent with the most recent National Health and Nutrition Examination Survey from 2011 to 2012 regarding obesity.

A key finding was that obesity could delay the presentation of Perthes patients to clinic. The study found that children with high BMI were diagnosed at a later stage of the disease compared to those with normal BMI. This finding raises the question of whether obesity itself delays the diagnosis of Perthes or other factors such as delayed access to medical care come into play.

In terms of treatment, children with high BMI were at least 2 times less likely than children with normal BMI to undergo surgery, including a hip arthrogram, casting or a bony procedure (femoral/pelvic osteotomy, etc.). The authors of the study believed that the lower rate was due to these patients presenting at a later stage of disease when it would be too late to do surgery.

To summarize, the information collected from the study suggest that obesity is highly prevalent in children with Perthes disease, at least in the state of Texas. The authors note that more studies are needed to confirm whether similar trends are found in other regions of USA and other countries.  Meantime, it is important for families with young children to not only be aware of Perthes, but also for doctors to understand the high prevalence of obesity in children with Perthes.

To read the full article, please click this link:


Getting to Know the Four Stages of Perthes

Perthes disease has four stages. The first stage, also known as the onset or necrosis stage, begins when the child first begins to limp and complain of pain. From the initial stage, the disease progresses as the body attempts to remove the damaged bone in order to begin new bone growth.

The Perthes stages include: onset stage à fragmentation stage à reconstitution stage à residual stage. Each stage of Perthes disease has key indicators, which signifies the progression of the disease through the various stages.

Onset (Synovitis, Necrosis, or Initial) Stage:

  • A limp and pain begins
  • Damage occurs when blood flow to the center of the hip stops working
  • Pain is usually mild and x-rays may appear normal
  • A crescent sign (crescent shaped crack) and a break can be seen under the joint surface
  • Duration: a few weeks to months


Fragmentation Stage

  • Stage where the body attempts to repair itself, but also the stage when most of the femoral head fragmentation and collapse occurs.
  • Brittle bone that lost its blood supply must be removed so that the body can grow new, healthy bone.
  • On x-rays, the ball of the hip appears broken up thus the term fragmentations. It sometimes looks like Swiss cheese with patchy holes, which are the areas where the dead bone is being removed by repairing cells.
  • The biggest concern at this stage is that the bone is at the greatest risk of collapsing – which can permanently deform the ball.
  • The outer part of the ball may also come outside of the joint.
  • Containment treatment is used in this stage if a part of the ball comes out of the joint. The ball is contained in the hip socket by casting, bracing, or surgery so that the socket can act as a mold to keep the ball round while the dead bone is adsorbed and new bone grows.
      • The main goal is to keep the ball in the socket during the fragmentation stage.
      • Containment is more effective if the treatment begins before the ball collapses (the ball does not collapse in every case of Perthes).
  • Duration: 6 months to a year


Reconstitution Stage (Reossification stage)

  • Occurs when all the dead bone, which appears white on x-ray has dissolved.
  • The shape of the ball at this stage may still improve as the patient grows. This is one of the reasons why a younger child affected with Perthes do better than an older child, since a younger child has more growth left. Containment treatment at this stage is no longer an effective treatment plan
  • Bone begins to fill in the holes of the ball. This is the stage when the ball starts to become bigger than the normal size in some children with severe Perthes. This is called coxa magna (big head). Growth of the femoral neck may also be affected and shows up as short and broad neck below the enlarged ball.
  • This stage usually becomes present by 18 months after the first onset of pain or limb occurs
  • It could take 2 to 3 years for the entire ball to be filled with new bone.
  • The child can return to full activity once the round, slightly enlarged shape of the ball is becoming visible on the x-ray


Residual Stage (Healed Stage)

  • Occurs when the ball has been replaced with bone
  • When the ball is round and the shape of the upper thighbone is normal, long-term outcome is very good and no arthritis is expected in most patients.
  • If the ball is oval shape, arthritis could develop by age 50 to 60 in about 50% of the patients.
  • The worst residual hips are flat or saddle shaped – the chance of getting early arthritis is higher. This is one of the reasons why we treat a child with Perthes early in order to prevent the ball from becoming very flat.  


Perthes Pairs: Looking further into genetics of Perthes disease

If you or your child has Perthes, you probably have wondered if the disease is genetic or inheritable. A recent article published in the Journal of Pediatrics, the official Journal of the American Academy of Pediatrics, looks into the chance of identical or fraternal twins having Perthes disease. If a high number of identical or fraternal twins both had Perthes, this finding would suggest a strong genetic cause for the disease. In the past, research has suggested that there is potential genetic cause to twins with Perthes, however the number of twins studied were small in number. This particular study analyzed 81 twin pairs with 10 pairs being identical twins and 51 fraternal twins. The study examined all twin pairs from the Danish Twin Registry (DTR), in which at least one of the siblings was diagnosed with Perthes disease. The DTR records all twins who are born in Denmark. From that group, the twins with Perthes were identified from various health records. From the 81 sets of twins, only 4 pairs of twins both had Perthes. Two sets were fraternal, and the other two were unknown to whether they were fraternal or identical. The study did show clustering of Perthes within a small number of families, however, the authors thought that this was due to each twin growing up or being exposed to similar environments. From previous studies, potential environmental factors that have been identified to be associated with Perthes include passive smoking and nutritional deprivation. In conclusion, the study found no evidence to support genetic cause for Perthes disease.

Although the study did not give a direct answer to the cause of Perthes, it provided more information into the many factors that can cause the disease. Since the study suggested family clustering, if one child is diagnosed with the disease, then the other children within the family have a slightly higher probability of having Perthes as well. Although the overall risk is still extremely low, it is important to pay close attention to signs of hip, knee, or thigh pain and limping in other children in the family.


My Child & Sports!

Will my child play sports again?               

Yes. Almost all children with Perthes will remain physically active. In fact, physical fitness is key to long term health of the hip.  However, many doctors may recommend a period of time when the child should avoid high impact sporting activities. Some families choose to limit certain activities, or even change sports altogether, if the patient experiences too much discomfort with the sport.

Petrie Cast?

What is a Petrie cast?

A Petrie cast is a cast on each leg from the thigh to the ankle with a bar in between holding the legs widely apart. This cast is typically placed in the operating room with the child under anesthesia. It is commonly done in conjunction with an injection into the hip joint called an arthrogram. This helps the surgeon better evaluate the hip. A release of a tight muscle in the thigh is also commonly done at the same time. The casts are usually maintained for 6 weeks. During this time the mobility of the child is limited to using a wheelchair and to a lesser extent a walker.

What about the other Hip?

What is the risk that it will happen to the other hip?

The best studies on Perthes list less than 15% as the risk of developing Perthes in the other hip.  It depends a bit on the age at which the first hip develops disease. Younger children may be at greater risk of the developing the disease in the other hip than older children. The other hip can develop the disease many years after the diagnosis of the initial hip.

Go team Go!

We are inspired by our patient family's story and how in the midst of the adversity of dealing with Perthes, this family has been able not only to raise local awareness on Perthes, but also to raise funds for the study of Perthes. Gabby was diagnosed with Perthes at age 7; as she and her family tried to decide what the best care for Gabby might be, they sought the opinion of  three different physicians at three different institutions, Gillette Children’s Specialty Healthcare, Mayo Clinic, and Boston Children’s
Hospital. The physicians with whom Gabby's family discussed the treatments options are all members of the International Perthes Study Group .

In an attempt to raise Perthes awareness, a fundraiser was held for Gabby, with the New Richmond
varsity girls basketball team hosting the event. Through Perthes Awareness T-shirt sales, the efforts that night raised funds for International Perthes Study Group research.

We are proud of the team of IPSG physicians and families working with us, to determine the best care possible for our Perthes Patients.



A second opinion?

Should I get a second opinion?

It is frequently not necessary. There are a lot of varying opinions about the treatment of Perthes Disease. A second opinion may add to your confusion though more information is typically better. Try to find a physician trained in Pediatric Orthopedic Surgery who has a special interest in Perthes disease. The IPSG patients benefit from the knowledge and expertise of surgeons around the world.


How Long?

How long will it last?

The initial symptoms of Perthes can last months to years, but the effects can be life long.  The symptoms of Perthes aren’t consistent. Some patients will have days or weeks at a time with little pain and minimal limp; however, for some time periods children will have more severe symptoms. The initial, active part of Perthes lasts  2 to 4 years.

FAQ: Run or Jump?

Why isn’t my child supposed to run or jump?

Some children will be recommended to avoid running and jumping activities depending of the severity and stage of their Perthes. The femoral head or ball of the hip joint becomes soft like play dough and can become misshapen. The thought is that the increased forces from running and jumping can cause the femoral head to change shape.

How to Help?

How can I help?

There is still a long way to go in understanding and treating Perthes disease, and support and help from all families is important.

The various ways to help involve:

  • Enrolling your child in a study and stay in the study. 
  • Actively share information about IPSG.
  • Donate to IPSG to support research.
  • Share your experience.
  • Visit and Like us on Facebook, and promote our page.


Hip Surgery?

What should I expect if my child has hip surgery involving the bone?

This of course depends on the child, the doctor, and the disease. Here are some generalized expectations that can vary widely.

The children with osteotomies tend to spend one to three nights in the hospital. They may or may not require a cast after surgery.  If they are casted, then it is usually for 6 weeks. Most children take oral pain medicine for about a week after surgery. They are typically out of school for one week.  Their doctor usually will want to see them post operatively around 1-2 weeks and again at 6 weeks. They will be intermittently followed with visits and x-rays until maturity. Your child will have limited weight bearing for at least 6 weeks and sometimes up to 6 months. They will typically need a lesser surgical procedure for the removal of the metal implant 6-12 months down the road.

FAQ of the Week!

What is perfusion MRI?

Perfusion MRI (magnetic resonance imaging) is an imaging study without radiation that evaluates the blood flow into the ball of the hip joint (femoral head). Depending on the age of the child, sedation or anesthesia may be required to get this test as the child must lie still for 30-45 minutes. Our study group believes that the perfusion MRI helps give an estimate of disease severity to help determine treatment.

FAQ of the week!

This week we answer some common questions about Perthes.

What causes it?

On the most basic level, Perthes is caused by a temporary loss of blood flow to the ball of the hip joint, but the reason for that loss of blood flow isn’t known.  Research associations have been made to
family history, injury, clotting diseases, ADHD, and second hand smoke exposure; but the exact cause of Perthes remains unknown. 


How long will it last?

The initial symptoms of Perthes can last months to years, but the effects can be
life long.  The symptoms of Perthes aren’t consistent. Some patients will have days or weeks at a time with little pain and minimal limp; however, for some time periods children will have more
severe symptoms. The initial, active part of Perthes lasts  2 to 4 years.

The Parents' Guide to Perthes

We are proud of the work and initiative taken by Betsy Miller and Dr. Charles Price.

In their recently published book “The Parents' Guide to Perthes:Understanding Legg-Calvé-Perthes Disease”, they have combined skilled writing and medical expertise to try and provide an avenue for parents/families dealing with perthes. This book is a great resource, as it delves into intricate parts of taking care and adjusting to all the treatment and recovery aspects for affected individuals.

Parents will be able to have personal testimonies from other parents that have gone through
similar situations.

You can purchase the book here:

"Crutch" (Transcending LCPD with crutches)

Our IPSG professionals prescribe the use of wheelchair or crutches for a number of patients every year, as a form of non-operative or post-operative treatment. The ordeal can be straining not only for families but also for the patients themsleves.

"Crutch" is a project that "chronicles the life of Bill Shannon, an internationally renowned artist and break dancer ..."  but Bill Shannon is no ordinary performer. Based on his experience wielding crutches, Bill addresses the stigma of crutch use in a very innovative format. He also exposes through "Crutch", the prejudice that those with certain types of disabilities can be subjected to.

Read more of the Story on here:

Support for this project can be made through here:

What’s new with Perthes research?

Dr. Harry Kim and his team at the Texas Scottish Rite Hospital for Children performed a MRI study which showed that children with Perthes have inflammation in the affected hip joint for a very long time.

Furthermore, the team discovered that a protein known to increase inflammation called interleukin-6 or IL-6 was significantly increased in the joint fluid. It is interesting that this protein is also elevated in children with juvenile rheumatoid arthritis. The team is actively engaged in research to understand how the elevation of the protein affects bone healing in Perthes and whether a treatment to stop this protein can improve bone healing. It is an exciting time for Perthes research.

 Stay tuned!


Quantitative assessment of synovitis in Legg-Calve-Perthes disease using gadolinium-enhanced MRI. Neal DC, O'Brien JC, Burgess J, Jo C, Kim HK, International Perthes Study G. Journal of pediatric orthopedics Part B. 2015 Mar;24(2):89-94. PubMed PMID:25305048.


Legg-Calvé-Perthes Disease Produces Chronic Hip Synovitis and Elevation of Interleukin-6 in the
Synovial Fluid. Kamiya N, Yamaguchi R, Adapala NS, Chen E, Neal D, O'Brien J, Thoveson A, Gudmundsson P, Brabham C, Aruwajoye O, Drissi H, Kim HK. J Bone Miner Res. 2015 Jan 1. doi: 10.1002/jbmr.2435. [Epub ahead of print]


Suicides related to Perthes?


Are Attention Deficit Disorder, Depression, and Suicide More Common in Patients with Perthes Disease?

By Chad Price, MD and Harry Kim, MD

The researchers in Sweden found that the prevalence of attention deficit hyperactivity disorder (ADHD), depression, and suicide was 2.5%, 3.7%, and 3.9% in people with Perthes, respectively, in their study published in the scientific journal Acta Orthopaedica  In comparison to the general population, people with Perthes were 50% more likely to have ADHD, 30% more likely to become depressed and almost three times more likely to commit suicide as adults. This is alarming but important information, so doctors and parents can watch for early warning signs of depression. Early treatment may help prevent depression from reaching the more serious stage of attempted suicide.

The authors of the study suggested that hyperactivity may contribute to repeated injury to the hip that may be a possible cause of Perthes. Also, psychological stress from chronic pain and limited physical activities due to Perthes later in life may increase the risk of depression. Another possibility is that the Attention Deficit Disorders evolve into depression later in life. However, there were no clear reasons why these conditions are linked to Perthes except to serve as a warning for parents and
patients that have been diagnosed with this condition. Simple measures in later life may help stem depression. For example, an article in the New York Times summarized the importance of exercise to decrease the risk of depression in adults. Perhaps patients who have had Perthes are not finding exercise activities that meet their needs.

Another finding was that heart attacks were 20% more common in patients with Perthes. The connection between Perthes and heart attack is not clear. One theory is that Perthes is caused by clotting of the blood vessels of the hips which may also increase the risk for clotting of the coronary arteries later in life. So, it may be important for patients with Perthes to do all they can to decrease their own risks for heart attacks including regular medical evaluations as adults.

This study raises important concerns for patients diagnosed with Perthes disease to act on, later in life. Identifying associated conditions may help develop better treatments and better understanding of problems faced in adulthood by some patients who had Perthes disease in
childhood. However, there is much more to be learned, and the International Perthes Study Group is dedicated to finding answers to, many questions about Perthes through collaborative work of many physicians who care about the patients with Perthes.

Perfusion MRI vs. Contrast MRI

What is the difference between Perfusion MRI and Contrast MRI?

Perfusion MRI is a type of contrast MRI but it is more sensitive for detecting blood flow. For both MRIs, a dye is injected into blood circulation before taking the MRI pictures. With the perfusion MRI, the MRI images are processed by computer to highlight where the blood flow is present or absent in the body. In a child with Perthes disease who has a whole femoral head necrosis, most of the femoral head will show an absence of blood flow (dye) in the femoral head in the early stage of the disease. Perfusion MRI can detect how much of the femoral head is involved earlier than regular, non-contrast MRI and x-ray.

Additional read on the subject is available at:,24590346,23872796,23478799


Fresh perspective!

2014 IPSG Annual Meeting: A Fresh perspective


Someone new at the meeting this year! 

Mallory Barth (mom of patient with Perthes) was our luncheon speaker.  She presented a parent’s perspective in dealing with Perthes and shared great ideas and suggestions on making our website more user friendly for parents.

Based on Mallory’s suggestions, we are currently developing a Parental Resource Tab to
incorporate FAQ’s and share information about supportive ideas and resources
for parents. 

We hope that these upgrades, along with our increasing Facebook traffic, will help more patients and parents, like Mallory, become actively involved with IPSG.

Using Perfusion MRI in Perthes

Perfusion MRI can detect the absence of blood flow in the affected femoral head of patients with Perthes disease.

Latest study published in the Journal of Bone and Joint Surgery by Dr Kim and colleagues show that perfusion MRI can predict the lateral pillar involvement before x-ray changes occur.

Reference: (J Bone Joint Surg Am. 2014 Jul 16;96(14):1152-1160. [Epub ahead of print] Perfusion MRI in Early Stage of Legg-Calvé-Perthes Disease to Predict Lateral Pillar Involvement: A Preliminary Study. Kim HK1, Wiesman KD1, Kulkarni V1, Burgess J1, Chen E1, Brabham C1, Ikram H1, Du J1, Lu A1, Kulkarni AV2, Dempsey M1, Herring JA1. PMID: 25031369 )

Safe Imaging Technique

Perfusion MRI is a safe and feasible imaging technique for perthes disease.

Five IPSG members recently reviewed the safety and feasibility of getting advanced MRI called perfusion MRI for Perthes disease in their respective hospitals. The results are published online in the Journal of Pediatric Orthopaedics. The doctors found that perfusion MRI is a safe and feasible imaging technique for the patient with Perthes disease but almost half of the patients required either sedation or general anesthesia to keep the patient still during the MRI. To read more please click on the following journal article.

Reference: Sankar WN, Thomas S, Castañeda P, Hong T, Shore BJ, Kim HK. Feasibility and Safety of Perfusion MRI for Legg-Calvé-Perthes Disease. J Pediatr Orthop. 2014 Feb 28. PMID 24590346

IPSG Annual Meeting

The International Perthes Study Group reviewed current progress and looked toward the future at their second annual meeting.

This was a big week for the Perthes Study Group (IPSG). October 3rd, 4th and 5th marked the 2nd annual meeting. In attendance was a select but diverse group of 31 physicians from four continents and eight different countries and included surgeons, a radiologist, statisticians, and research assistants. The unifying principle that all these researchers hold is a dedication to furthering understanding of Perthes disease and improving the care of Perthes patients by performing quality research. The pivotal tool in early treatment decision-making is perfusion MRI (a special MRI technique which holds promise to provide early detection for which patients may benefit from surgical treatment and which patients will simply be observed).

In this meeting we reviewed progress over the last year. Much has been achieved in the research group's brief history. Seventeen of the institutions have already gained IRB approval for patient enrollment, an MRI protocol has been established, data collection standardized, an internationally accessible database created, a website for patients and providers created, and funding of over a quarter-million dollars secured including two research grants. Several papers including a review of Perthes, two papers on the use of perfusion MRI, and several other presentations have already been written. In less than two years, this group is already changing patient care.

Even though it was discovered and named over one-hundred years ago, Perthes disease is such a rare and frustrating condition where little is known because even surgeons in large, research centers only see a handful of patients per year. Answers to treatment questions can only be answered when information is collected from large numbers of patients. One of the most useful achievements is the ability to pool the patients and experience from all the academic centers from around the world and learn from the combined experience and data collected.

The group agreed on stringent membership criteria which included institutional review board (IRB) approval, enrollment of patients in the group's prospective trials, and at least 75% patient follow-up. Future short-term goals for the group are to complete and publish the modified Waldenstrom classification staging study, complete the PROMIS outcomes survey, complete the perfusion MRI estimation study.

-John Tis, M

Is there an association between Perthes disease and female gymnasts over age 10?

Latest study on Perthes disease by IPSG members from Mayo Clinic and Texas Scottish Rite Hospital found 7 of 9 female patients (78%) aged 10 years and older were involved in high-level competitive gymnastics when they presented with Perthes disease. The investigators suggest that further studies are needed to explore the association between the physical demands of advanced gymnastic training and the development of Perthes disease in this subset of patients. Please contact us if you have questions or have seen this in your practice.

Reference: Larson AN, Kim HK, Herring JA. Female Patients With Late-Onset Legg-Calvé-Perthes Disease Are Frequently Gymnasts: Is There a Mechanical Etiology for This Subset of Patients? J Pediatr Orthop. 2013 Sep 21. PMID: 24065070

The International Perthes Study Group will be meeting in Dallas, Texas for their second annual meeting.

The second annual International Perthes Study Group meeting is less than a month away. Over 30 study investigators involved in the study group will be meeting in early October to discuss research progress, current treatment results, and plan for future studies. Additionally, the group will be meeting to expand patient outreach to better educate patients and their families about Perthes and current research being done on Perthes disease. We are looking forward to the great opportunity for our members with an interest in learning more about Perthes disease to come together and build upon each others' experiences in treating patients with Perthes disease.

A preliminary study on the role of perfusion MRI on predicting the short-term outcome of Perthes disease is now published online in the Journal of Pediatric Orthopaedics.

This study found that perfusion MRI findings correlated with radiographic deformity at the 2-year follow-up. This pilot study shows the promise of perfusion MR as a possible early prognosticator of outcome in Perthes disease that can be applied in the early stages of the disease prior to any deformity. Previous methods to evaluate outcomes once Perthes disease has healed could only be applied after the femoral head had deformed. Perfusion MRI also provides a 3-D evaluation tool for providers to evaluate how much of the femoral head is involved in the disease which could inform treatment options. To read the summary of this paper click here: PMID: 23872796.

Reference: MR perfusion index as a quantitative method of evaluating epiphyseal perfusion in Legg-Calve-Perthes disease and correlation with short-term radiographic outcome: A preliminary study. Du J, Lu A, Dempsey M, Herring JA, Kim HKW. J Pediatr Orthop. 2013 Jul 17.

IPSG Investigators awarded a POSNA Clinical Trials Planning Grant in 2013

An IPSG project entitled, “Assessment of Quality of Life in Patients with Legg-Calve-Perthes Disease” was awarded a 2013 POSNA Clinical Trials Planning Grant (PI: Joshua E. Hyman, CO-PI: Harry K.W. Kim, CO-I: Hiroko Matsumoto, Norman Otsuka, Junichi Tamai, Charles T. Mehlman, Wudbhav N. Sankar, Harish Hosalkar). The purpose of this study is to investigate the validity of PROMIS in patients with LCPD. PROMIS was developed by the NIH to assess patient quality of life. PROMIS Questionnaire, UCLA activity scores, Demographic and Modified Waldenstrom Classification data will be collected on patient age 0-18 at any stage of LCPD. For patients 8 and older, patients will complete the self report and for patients younger than 8 years old, a parent will complete the proxy questionnaire. Columbia University will generate and distribute a list of unique login/passwords for each site. The IRB has been obtained at Columbia University and will shortly be distributed to participating sites. A conference call is scheduled in July to train study coordinators at each participating sites in questionnaire administration.

IPSG Decides on Study Protocol for Patients who develop Perthes disease after age 11

IPSG held meeting during POSNA to finalize >11 age group protocol. Presented by Prof Ralf Stücker of Children’s Hospital Hamburg, patients in this age group will be separated into two groups: 3mm collapse at time of enrollment. There will be three treatment arms to the 3mm collapse, the study is open to all treatments.

This meeting also brought further discussion of the validity study for modified Waldenström Staging of Perthes disease. Dr. Josh Hyman of Morgan Stanley Children’s Hospital in New York presented study protocols for participating investigators with expectation to submit results for a POSNA 2014 abstract.

IPSG Gains Visibility at 2013 POSNA Annual Meeting in Toronto, ON

The IPSG presented an e-Poster at the annual POSNA meeting in Toronto on the accomplishments of the study group to date. The IPSG has graciously been supported by a POSNA Clinical Trial Planning Grant and was happy to present the POSNA membership with updates on their progress. Dr Harry Kim of Texas Scottish Rite Hospital received several inquiries about group participation during the meeting.

Does contrast-Enhanced MRI more clearly depict femoral head area of necrosis than non-contrast MRI?

Current treatments for Perthes disease are most effective when applied during the early stages of Perthes disease, prior to the femoral head collapsing and breaking apart. Radiographic prognosticators during these early stages of Perthes Disease are needed to guide treatment decisions. Commonly, patients receive x-rays to evaluate the extent of involvement of the femoral head. MRI provides 3D imaging of the femoral head and gadolinium-enhanced MRI with subtraction technique reveals information about the blood flow to the head. This technique can reveal early ischemia prior to significant flattening and fragmentation of the bone in the later stages of the disease.

Dr Harry Kim and the research team at Texas Scottish Rite Hospital for Children investigated pre and postcontrast MRI for reliability of measuring the amount of femoral head necrosis involvement during the initial stage of Perthes disease. Patients diagnosed with Perthes disease between the ages of 6 and 14 in Waldenström stage 1 of the disease were prospectively enrolled. Each child received an MRI with and without contrast as soon as possible after initial examination. The area of head involvement was measured on each MRI by 3 pediatric radiologists and 1 pediatric orthopedic surgeon.

Authors concluded that the postcontrast MRI showed greater reliability in measuring the area of head involvement. They qualitatively agreed that the contrast-enhanced MRI more clearly showed this area.

Reference: A comparison of non-contrast and contrast-enhanced MRI in the initial stage of Legg-Calvé-Perthes disease. HKW Kim, Kaste S, Dempsey M, and Wilkes D. Pediatric Radiology PMID: 23478799 [Epub ahead of print]

Can the radiographic outcomes of Legg-Calvé-Perthes be reliably assessed at skeletal maturity?

Traditionally, the outcome of treatment of Perthes disease has been assessed by characterizing the shape of the femoral head, the structure of the acetabulum, and the interface between those two hip joint structures. The most common classification system in use today is that developed by Stulberg et. al. that categorizes the affected hip into one of five different classifications. The benefit of this system is that it has been shown to predict the likelihood of degenerative arthritis. However, this classification system is currently limited in its lack of high reproducibility.

Hitesh Shaw, Benjamin Joseph, and other investigators from Kasturba Medical College in Manipal, India sought to develop a method to depict reliable and continuous outcome measures for the treatment of Legg-Calve-Perthes disease. To accomplish this feat, they used image analysis software on anteroposterior and lateral radiographs of hips of skeletally mature individuals with healed Perthes disease.

The research team reported high reliability of measures of sphericity and congruency of the femoral head and acetabulum (a measure of how well the curvature of the femoral head and acetabulum match). These two continuous measures have yet to be correlated with other outcomes such as early arthritis and impingement.

Reference: Quantitative Measures for Evaluating the Radiographic Outcome of Legg-Calve-Perthes Disease. Shah H, Siddesh ND, Pai H, Tercier S, and Joseph B. The Journal of Bone & Joint Surgery PMID: 23426770