Want Dr. Calendine’s articles to stand out in your Google and AI search results? Add him as a preferred source (one tap).
Adolescent hip dysplasia is one of the most missed causes of hip pain in teenagers and young adults. I know that because I see the end result. After more than twenty years replacing hips, I can tell you that many “worn out” hips in patients in their forties were shaped wrong from the start, and nobody caught it in time.
What is adolescent hip dysplasia?
Adolescent hip dysplasia is a hip socket too shallow to properly hold the ball of the thigh bone, found or becoming painful during the teenage years. The ball is the femoral head (the top of the thigh bone) and the socket is the acetabulum, a cup built into the pelvis. In a healthy hip, the cup wraps well around the ball and spreads your weight across a wide surface of cartilage.
In a dysplastic hip, the cup is shallow or tilted, so the same body weight lands on a much smaller patch of cartilage. Think sneakers versus high heels on a carpet: same weight, very different pressure.
The labrum (the rubbery ring of cartilage around the rim of the socket) gets pinched and eventually torn. That’s often when a teenager first feels pain.
How is adolescent hip dysplasia different from hip dysplasia in babies?
It’s the same problem found at a different age, usually milder. Developmental dysplasia of the hip (DDH) is screened for in every newborn, and the severe forms get treated in infancy. The mild forms slip through, because a slightly shallow socket doesn’t hurt a five-year-old.
It starts to hurt when the child grows, gets heavier, and takes up sports, which is why symptoms so often begin between ages 12 and 20.
What causes hip dysplasia in teenagers?
Adolescent hip dysplasia is caused by a hip socket that didn’t finish developing normally in childhood, and the exact reason is often unknown. The four classic risk factors are being female, being a firstborn child, being born breech (feet or bottom first), and having a family history of hip dysplasia.
Girls are affected more often than boys, partly because of pelvic shape and partly because looser ligaments let a shallow socket drift. Both hips are involved in about 40 percent of patients.
Does hip dysplasia run in families?
Yes, and strongly. Roughly half of patients diagnosed with hip dysplasia have a relative with hip disease, and a parent or sibling of someone with dysplasia has about a 25 percent chance of having it too.
Here’s what I tell families across the desk: if a parent had a hip replacement before 55 and now a daughter has groin pain, say so at the appointment. It changes how fast a specialist reaches for the right X-ray.
What are the symptoms of adolescent hip dysplasia?
The most common symptom of adolescent hip dysplasia is a deep ache in the groin that gets worse with activity and toward the end of the day. Many teenagers describe it by cupping a hand around the front and side of the hip in a C shape, which specialists call the “C sign.”
Other common symptoms:
- Pain or fatigue on the outside of the hip after standing, walking, or sports
- Catching, clicking, popping, or locking in the groin
- Pain sitting in a low chair, in a car, or in deep squats
- One leg feeling shorter than the other
Symptoms start mild and occasional, then return more often. Pain that keeps circling back is the pattern to take seriously.
Is it normal for a teenager to have hip pain?
Occasional soreness after a hard practice is normal; groin pain that lingers for weeks is not. In one review of adolescents with dysplasia, most had seen several providers and lived with pain for a long time before anyone named the problem.
One warning sign: a teenager who suddenly limps and cannot bend the hip without turning the foot outward needs an X-ray that day. That can mean a slipped capital femoral epiphysis, a growth-plate injury that is urgent.
How is adolescent hip dysplasia diagnosed?
Adolescent hip dysplasia is diagnosed with a physical exam plus a standing X-ray of the pelvis, with MRI or CT added when more detail is needed. During the exam, a specialist moves the hip through its range of motion and uses a few tests that reproduce the pain. Teens with dysplasia often have more motion than normal.
The X-ray is the workhorse. It has to be taken standing, because that’s how the hip is loaded in real life, and read by someone who measures hip coverage rather than glancing for arthritis. I’ve reviewed X-rays called “normal” for years where the shallow socket was plain to see once you drew the lines.
What does the X-ray measure?
The key number is the lateral center-edge angle, which tells us how much of the ball is covered by the socket. An angle below about 20 degrees is considered dysplastic, 20 to 25 is borderline, and above 25 is normal.
An MRI shows the labrum and cartilage; a CT scan maps the socket in three dimensions when surgery is planned. In my clinic, that’s the order: X-ray first, then MRI or CT only if needed.
How is adolescent hip dysplasia treated?
Adolescent hip dysplasia is treated with physical therapy and activity changes in mild cases, and with a surgery called periacetabular osteotomy (PAO) when the socket needs to be repositioned. The goal at every stage is the same: relieve pain and keep the natural hip working for as many years as possible.
Nonsurgical treatment comes first for mild dysplasia without labral or cartilage damage:
- Physical therapy for the core, back, and hip muscles. Muscle can’t deepen a socket, but strong hips act as backup stabilizers.
- Activity changes, such as swapping deep squats and distance running for cycling or swimming during a flare.
- Anti-inflammatory medication in short courses.
- Watchful waiting with follow-up X-rays every 6 to 12 months.
What is a periacetabular osteotomy (PAO)?
A periacetabular osteotomy is a surgery that cuts the pelvic bone around the socket, rotates the socket into a better position over the ball, and holds it there with screws while the bone heals. The operation takes 2 to 3 hours. It’s done in patients at or near skeletal maturity, from roughly age 11 into the early forties, as long as the cartilage is still healthy.
I want to be clear about something: I don’t perform PAO. It belongs with hip preservation surgeons who do it week in and week out. What I do is recognize dysplasia, explain it, and make sure a young patient reaches the right specialist without losing another year.
In my experience, the patients hurt most by this condition aren’t the ones who had the wrong surgery. They’re the ones who had no diagnosis at all.
How long is recovery after PAO surgery?
Recovery from PAO takes about a year, and the first three months are the hardest. Most patients stay in the hospital 2 to 4 days and use crutches for 6 to 12 weeks while the bone heals. Most return to selected activities by 4 to 6 months and sports by 12 months.
Results hold up well when surgery comes before arthritis. More than 90 percent of patients still have pain relief 10 years after PAO, and about 75 percent at 20 years. Roughly one-third of hips are still doing well at 30 years without a hip replacement.
What happens if adolescent hip dysplasia goes untreated?
Untreated adolescent hip dysplasia leads to early hip osteoarthritis, often decades ahead of schedule. The Norwegian Arthroplasty Register traced as many as 26 percent of hip replacements back to untreated dysplasia, and in the 1939 study that first described the condition, every patient followed for 30 years developed arthritis.
When a dysplastic hip does wear out, hip replacement is still a very good operation. I’ve done it for many patients in their forties who never heard the word dysplasia until they sat in my office. Because the socket is shallow and tilted, I sometimes choose a posterior approach for these hips instead of my usual anterior approach.
When should you see a specialist in Middle Tennessee?
See an orthopaedic specialist when a teenager or young adult has hip or groin pain that has lasted more than a few weeks, keeps returning, or limits sports, sitting, or sleep. Don’t wait for a limp. Bring the family history and ask whether the standing pelvis X-ray shows normal hip coverage.
At the Bone and Joint Institute of Tennessee, 3000 Edward Curd Lane, Franklin, TN 37067, I evaluate adult hip pain for patients from Franklin, Brentwood, Nashville, Spring Hill, Columbia, Murfreesboro, and across Middle Tennessee. If your hip pain started young and you’ve been told it’s “just arthritis,” I’d like to look at your X-ray with you. You can schedule a consultation online or call (615) 791-2630.
If the patient is a teenager, call (615) 791-2630 and tell the team you’re calling about a young hip. Our practice will help direct your family to the right fellowship-trained specialist, whether that’s here or with a hip preservation surgeon. I’d rather never meet a 45-year-old whose hip could have been preserved at 15.
This article is for educational purposes only and is not a substitute for evaluation by a qualified orthopaedic specialist. Individual results vary. Talk with your physician before making decisions about your care.
References
- Ellsworth BK, Sink EL, Doyle SM. Adolescent hip dysplasia: what are the symptoms and how to diagnose it. Curr Opin Pediatr. 2021;33(1):65-73. PubMed
- Lerch TD, Steppacher SD, Liechti EF, Tannast M, Siebenrock KA. One-third of hips after periacetabular osteotomy survive 30 years with good clinical results, no progression of arthritis, or conversion to THA. Clin Orthop Relat Res. 2017;475(4):1154-1168. PubMed
- Wyles CC, Vargas JS, Heidenreich MJ, et al. Hitting the target: natural history of the hip based on achieving an acetabular safe zone following periacetabular osteotomy. J Bone Joint Surg Am. 2020;102(19):1734-1740. JBJS
- Lee CB, Mata-Fink A, Millis MB, Kim YJ. Demographic differences in adolescent-diagnosed and adult-diagnosed acetabular dysplasia compared with infantile developmental dysplasia of the hip. J Pediatr Orthop. 2013;33(2):107-111. PubMed
- Nunley RM, Prather H, Hunt D, Schoenecker PL, Clohisy JC. Clinical presentation of symptomatic acetabular dysplasia in skeletally mature patients. J Bone Joint Surg Am. 2011;93 Suppl 2:17-21. JBJS
- Engesaeter IO, Laborie LB, Lehmann TG, et al. Prevalence of radiographic findings associated with hip dysplasia in a population-based cohort of 2081 19-year-old Norwegians. Bone Joint J. 2013;95-B(2):279-285. PubMed
