Question 1

My 7-year-old son was diagnosed with Perthes disease and the surgeon says we should 'just watch it'—shouldn't we do something more aggressive to fix his hip?

Accepted Answer

The 'benign neglect' or observation approach feels counterintuitive when your child has a serious hip problem, but for many children it's the evidence-based best treatment. Here's why: NATURAL HISTORY: Perthes disease is self-limiting—the femoral head WILL heal over 2-4 years regardless of treatment. The question is: will it heal round (good outcome) or flat (poor outcome)? Treatment aims to maximize roundness, but can't speed healing. TREATMENT GOALS: All treatments (surgical and non-surgical) have one goal: 'containment'—keeping femoral head centered in socket while it's soft so it molds into round shape rather than mushrooming outward into flat shape. AGE IS CRITICAL FACTOR: Children under 6 years have excellent natural outcomes (85-90% heal well with observation alone) because: (1) More growth remaining to remodel any deformity; (2) Hip naturally well-contained due to age-appropriate anatomy; (3) Surgery doesn't improve outcomes and adds risks. Children 6-8 years—intermediate zone where decision depends on X-ray findings (lateral pillar classification). Pillar A or B—observation may be adequate. Pillar B/C or C—surgery may help. Children over 8 years with severe involvement—surgery may improve outcome but can't guarantee good result. YOUR SON (age 7): Decision depends on X-ray classification. If Lateral Pillar A or early B, observation with physiotherapy and activity modification is appropriate standard of care. If Lateral Pillar B/C or C, containment surgery (femoral or pelvic osteotomy) may be recommended. WHAT OBSERVATION ENTAILS: Not 'doing nothing'—requires: (1) Activity modification (no high-impact sports, encourage swimming/cycling); (2) Physiotherapy 2-3 times weekly to maintain hip motion (stiffness impairs containment); (3) X-rays every 3-6 months to monitor; (4) Willingness to proceed to surgery if hip 'at risk' of poor outcome. Many parents find observation difficult psychologically but it's based on decades of research showing surgery doesn't help young children with mild-moderate disease.

Question 2

Will my child develop arthritis when they're older, and if so, when might they need a hip replacement?

Accepted Answer

Honest answer: Risk of eventual hip arthritis depends on how round the femoral head heals. Perfect round head—low arthritis risk (similar to general population). Mildly irregular head (Stulberg I-II)—10-20% develop mild arthritis, usually not until 50s-60s. Moderately irregular head (Stulberg III)—40-50% develop arthritis in 40s-50s, some need hip replacement. Severely irregular/flat head (Stulberg IV-V)—70-80% develop arthritis in 30s-40s, most eventually need hip replacement. PREDICTING OUTCOME: Can't know final head shape until disease healed (2-4 years from diagnosis). Favorable factors: age under 6 years, less than 50% head involvement, good containment, maintained hip motion. Unfavorable factors: age over 8 years, more than 50% head involvement, lateral extrusion, stiff hip. ARTHRITIS TIMELINE IF DEVELOPS: Early 30s—if very poor outcome (Stulberg V) with flat head. 40s-50s—most common time for arthritis symptoms if moderate outcome (Stulberg III-IV). 50s-60s—similar to general population if good outcome (Stulberg I-II). HIP REPLACEMENT CONSIDERATIONS: Modern hip replacements last 15-20+ years, so if your child needs one at age 35, they'll likely need 2-3 revisions over lifetime (each more difficult than last). Surgeons try to delay first replacement as long as possible using activity modification, anti-inflammatories, steroid injections. However, quality of life matters—if severely limited by pain in 30s, replacement appropriate despite young age. REALISTIC COUNSELING: If your child 5 years old with mild disease (Pillar A)—excellent chance of good outcome, low arthritis risk. If your child 8 years old with severe disease (Pillar C)—prepare for likelihood of early arthritis and possible hip replacement in adulthood. Between these extremes—uncertain outcome, need to wait and see how head heals. Focus now on maximizing containment to give best chance of good outcome.

Medical Disclaimer

Hip Blood Supply Problem in Children (Perthes Disease)

📖What is Hip Blood Supply Problem in Children (Perthes Disease)?

🔬What Causes It?

⚠️Risk Factors

You may be at higher risk if:

🛡️Prevention