What Happens to Adults Who Had Perthes Disease as a Child?

Most adults who had Perthes disease in childhood lead active lives, but the condition leaves a lasting mark on the hip joint that can surface decades later. The central issue is the shape the femoral head takes after healing: a hip that remodels into a round ball typically functions well for a lifetime, while one that heals flat or misshapen is far more likely to develop arthritis and eventually need a hip replacement. How well an adult fares depends largely on factors that were set in motion during childhood, particularly the age at onset and how much of the femoral head was involved.

Why the Shape of the Healed Femoral Head Matters So Much

Perthes disease temporarily cuts off blood supply to the growing femoral head, causing bone to soften, fragment, and gradually rebuild. The shape the femoral head takes once that rebuilding is complete is the single strongest predictor of how the hip will perform in adulthood. Surgeons classify healed hips by their degree of roundness, often using the Stulberg system, which groups outcomes from perfectly spherical to severely flattened. A study following patients for an average of 48 years found that hips that healed into a spherical shape had a 50-year survival rate of about 99%, meaning almost none of those patients ever needed a hip replacement. Ovoid (egg-shaped) hips survived at roughly 76%, and flat hips dropped to about 48%.¹ In a separate long-term study, the association between a worse Stulberg classification at five-year follow-up and an unsatisfactory outcome in adulthood was strong and statistically significant.²

The practical message is that an adult who had Perthes disease can get a good sense of their long-term outlook from imaging. If childhood X-rays showed a round femoral head at skeletal maturity, the odds strongly favor a hip that lasts. If the head healed flat, the risk of progressive arthritis and eventual surgery is much higher, though even in that group nearly half still had their own hip joint at the 50-year mark.

Age at Onset and Gender

Children who develop Perthes disease before the age of about six tend to do substantially better in the long run than those diagnosed later. Younger children have more growth remaining, which gives the femoral head more time and capacity to remodel into a rounder shape. In the 48-year follow-up study, children diagnosed before age six needed hip replacement at a rate of about 10%, compared with 28% for those diagnosed at six or older.¹

Gender plays a role as well, though it is often underappreciated because Perthes disease is far more common in boys. Research controlling for disease severity and treatment approach has found that girls are more likely to have worse radiological outcomes by skeletal maturity, and this effect becomes more pronounced when the disease starts after age eight.³ In an international survey of over 900 adults who had Perthes disease, women reported significantly worse hip function and general health scores compared to men across multiple measures.⁴ The reasons probably combine biology (less remodeling potential in girls who mature earlier) with biomechanics (girls tend to have a wider pelvis, which changes joint loading).

When Hip Replacement Enters the Picture

Hip replacement is the most significant surgical outcome for adults with a history of Perthes disease, and the rates vary widely depending on how the hip healed and how long you follow people. A meta-analysis pooling data from multiple studies found overall hip replacement rates of roughly 5% to 7% across mixed follow-up periods. But the numbers climb steeply with time: among conservatively treated patients followed for more than 40 years, the rate reached about 23%, and among surgically treated patients followed that long, it reached roughly 18%.⁵ A Canadian population study found even higher rates over long follow-up, with about a third of patients in both operative and nonoperative groups eventually needing the procedure, though the average age at surgery differed: around 34 for those who had childhood surgery versus 46 for those treated without an operation.⁶

These numbers can sound alarming, but context matters. The 48-year study found only 19% of its entire cohort had undergone hip replacement, and spherical hips were almost completely spared.¹ The variation across studies reflects differences in disease severity within each cohort, the era of treatment, and follow-up length. The bottom line is that many adults never need a hip replacement, but those with flat or substantially deformed femoral heads face a coin-flip probability over a lifetime.

Why Hip Replacement Is More Complicated in Perthes Patients

When adults with a history of Perthes disease do need a hip replacement, the surgery is not as straightforward as it is for a typical arthritis patient. The altered anatomy of the proximal femur presents real challenges for the surgeon. The femoral head and neck may be irregularly shaped, the femoral canal can be narrow or bowed, and the acetabulum (hip socket) may have adapted to the misshapen head over decades. If the person had childhood surgery, there may be additional scarring, hardware tracks, or abnormal bone geometry to contend with.⁷

The rate of complications during and after the procedure, including fracture and nerve injury, has been reported as higher in Perthes patients than in the general population undergoing the same surgery. Reoperation rates tend to be elevated too. That said, experienced surgeons who specialize in complex hip reconstruction routinely manage these cases successfully. Techniques that address acetabular bone deficiency, for instance, have shown good results lasting over a decade with high functional scores.⁸ The key takeaway is that if you are an adult with Perthes history and hip replacement is on the horizon, seeking a surgeon with specific experience in post-Perthes anatomy is worth the effort.

Femoroacetabular Impingement and Hidden Joint Damage

Well before arthritis develops, many adults with a Perthes history experience hip pain from femoroacetabular impingement. The misshapen femoral head, often described as mushroom-shaped, loses the smooth offset between the head and neck that allows the hip to rotate freely. Instead, the enlarged or bumpy head jams against the rim of the socket during movement, particularly during deep flexion or rotation. This repeated collision damages the labrum (the ring of cartilage lining the socket rim) and grinds down the joint surface over time.⁹

A study of residual Perthes deformities using arthroscopy and open surgical inspection found labral abnormalities in 76% of hips, acetabular cartilage damage in 59%, and femoral head cartilage abnormalities in 81%.¹⁰ In a separate series of patients followed into adulthood, about a third of hips had a palpable femoral bump on imaging, and hip pain correlated strongly with both the presence of that bump and the degree of femoral head flattening.¹¹

This is an area where awareness has grown rapidly. Many young adults with lingering Perthes-related hip pain are now being evaluated for impingement, and hip-preservation surgery (reshaping the femoral head and repairing labral tears) can provide meaningful pain relief and potentially delay the trajectory toward arthritis. The evidence on how well these procedures hold up over decades is still accumulating, but for younger patients who are not yet candidates for hip replacement, impingement surgery fills an important gap.

Living with the Hip Between Childhood and Surgery

For the large group of adults whose Perthes-affected hips are imperfect but not yet arthritic enough for replacement, daily life involves a spectrum of function. Swedish research found that over 90% of adults with a Perthes history were physically active at moderate or high levels, yet about half reported ongoing pain.¹² Quality-of-life scores were significantly lower than the general population across all age groups, a finding echoed in the large international survey of over 900 adults, where hip-specific function scores and general health measures were consistently below population norms.⁴

People who were obese, who reported receiving no treatment in childhood, or whose disease started after age 11 fared worst on these measures. The pattern suggests that body weight management and appropriate childhood intervention both matter for long-term outcomes. Practically speaking, adults with a Perthes history who stay active and maintain a healthy weight tend to function better, though the disease still exacts a measurable toll on comfort and quality of life that most people learn to work around rather than fully resolve.

What Happens After Hip Replacement

Hip replacement generally improves life for adults with Perthes-related arthritis, but the picture is more nuanced than it is for typical osteoarthritis patients. An international survey comparing Perthes patients who had undergone hip replacement with those who had not found that women under 45 who received a hip replacement actually reported worse pain, symptom, and daily-activity scores compared to population norms, and their sports and recreation scores remained low across all age groups. However, when compared to Perthes patients of the same age and sex who had not had hip replacement, women aged 35 to 54 with a hip replacement reported significantly better outcomes on almost every scale.¹³

The interpretation is that hip replacement moves Perthes patients from a worse baseline to a better one, but does not fully normalize the hip. Younger women appear to benefit clearly in terms of pain and symptoms. Sports and high-demand activities remain a weak point even after surgery, which makes sense given the altered anatomy and the activity restrictions surgeons typically recommend for implant longevity. For younger patients, the question of implant lifespan also looms: a hip replacement done at 35 may need to be revised once or even twice over a lifetime, which loops back to the anatomical challenges discussed earlier.

Leg Length Discrepancy

A less-discussed but common consequence of Perthes disease is a difference in leg length. Because the disease disrupts growth of the proximal femur during childhood, the affected leg often ends up shorter. One study measuring leg length in Perthes patients found a mean discrepancy of about 1.8 cm, with the shortening driven primarily by changes in the distance from the hip center to the top of the thighbone rather than the shaft itself.¹⁴ Some patients had undergone a growth-plate procedure (epiphysiodesis) on the longer leg in childhood to even things out, which reduced the discrepancy to about 1.3 cm by skeletal maturity.

A leg length difference of a centimeter or two can seem trivial, but over decades it changes gait mechanics and can contribute to low back pain, knee strain on the longer side, and general fatigue during prolonged standing or walking. A shoe lift is a simple and effective solution that many adults use. The discrepancy also matters a great deal at the time of hip replacement: surgeons need to account for the shortened proximal femur when selecting implant sizes and positioning, and patients should understand that “equalizing” leg length during surgery is not always straightforward when the anatomy has been remodeled by the disease.

Does Childhood Treatment Change the Adult Outcome?

Parents of children with Perthes disease often want to know whether surgery or bracing will make a difference decades later. The honest answer is that the evidence is less decisive than you might hope. A study comparing surgical and conservative treatment in children with late-onset disease found no statistically significant difference in radiographic outcomes at skeletal maturity, though there were twice as many patients with poor results in the conservative group.¹⁵ A systematic review with meta-analysis similarly found limited evidence for a clear winner, with results varying by disease stage.¹⁶

The meta-analysis on hip replacement rates found that for children diagnosed before age seven, the difference in hip replacement rates between surgical and conservative treatment was negligible. For those diagnosed after age seven, surgery appeared to substantially lower the rate of eventual hip replacement compared to conservative management.⁵ The pattern makes intuitive sense: younger children have enough remodeling capacity that both approaches can work, while older children may benefit more from surgical containment of the femoral head to maintain its shape during healing.

Bilateral Perthes Disease

About 10% to 15% of children with Perthes disease develop it in both hips, either simultaneously or sequentially. Parents and patients understandably worry that bilateral involvement doubles the trouble. A comparative study found that the radiological outcomes in bilateral disease were comparable to those in unilateral disease when matched for age of onset, and that early surgery had a similar effect in both groups. The age at which the disease started remained the dominant factor in determining how well the hips fared, regardless of whether one or both sides were affected.¹⁷ This is reassuring: having both hips involved does not automatically mean worse outcomes per hip, though it does mean the person is dealing with the cumulative effect of two potentially imperfect joints and may face the prospect of bilateral hip replacement down the road.

Joint-Preserving Surgery for Younger Adults

A growing area of interest is joint-preserving surgery aimed at improving hip mechanics before arthritis sets in. Surgical hip dislocation with reshaping of the femoral head and neck is one approach that has shown promise. In a series of patients treated this way, hip function scores improved significantly, rising from an average of about 66 preoperatively to 87 at a mean follow-up of roughly four years. The procedure also improved the relationship between the greater trochanter and the center of the femoral head, which helps normalize the pull of the hip abductor muscles and reduces the characteristic limp that many Perthes patients develop.⁹

These procedures are technically demanding and not widely available, but they represent a meaningful option for younger adults (typically in their twenties or thirties) who have significant symptoms but are too young for hip replacement. By addressing the mechanical mismatch between the deformed femoral head and the socket, joint-preserving surgery can buy years of better function and potentially delay the need for an artificial joint. The tradeoff is a longer, more involved recovery compared to arthroscopic procedures, and the outcomes are best in hands with substantial experience.

The Psychological Side

Research on the emotional and psychological effects of Perthes disease in adulthood is thinner than the orthopedic literature, but the surveys that exist paint a consistent picture. Adults with Perthes history report lower quality-of-life scores not just on physical scales but on social and mental health measures as well.⁴ Chronic hip pain that starts in young adulthood, the uncertainty of when or whether surgery will be needed, activity limitations that set you apart from peers, and a visible limp all contribute to a psychological burden that is easy to overlook in a condition defined by X-ray findings. Many adults describe feeling caught between being “too young for a hip replacement” and too symptomatic to live the way they want, a frustrating limbo that standard orthopedic follow-up does not always address. Connecting with other adults who share the experience, through patient organizations and online communities, is something many people find genuinely helpful for navigating that gap.