DDx Hip Pain

Modern Study Review (AI-Generated)

High-Yield Summary

Unilateral hip pain in pediatric and adult populations requires a broad differential diagnosis encompassing congenital, traumatic, developmental, vascular, inflammatory, neoplastic, infectious, and metabolic etiologies. Accurate diagnosis is critical to guide timely management and optimize pain relief and function. Modern imaging and clinical algorithms help differentiate these causes, with particular attention to conditions that threaten joint integrity or systemic health.

Key Diagnostic Findings

Anatomy

• Hip joint: ball-and-socket articulation between femoral head and acetabulum.
• Surrounding structures: proximal femur, pelvis (ilium, ischium, pubis), growth plates in pediatric patients, and soft tissues including bursae and muscles.

Clinical Presentation

• Pain location: groin, lateral hip, buttock, or thigh.
• Onset: acute (trauma/infection) vs. insidious (developmental/neoplastic).
• Associated symptoms: limp, fever, systemic signs, limited range of motion.

Imaging

• X-rays: First-line for fractures, developmental dysplasia, slipped capital femoral epiphysis (SCFE), Perthes disease, and neoplasms.
• MRI: Superior for early osteonecrosis, chondrolysis, infection, and soft tissue evaluation.
• Bone scan/CT: Adjuncts for occult fractures or tumor staging.

Classification Systems

• SCFE: Stable vs. unstable classification guides treatment urgency.
• Perthes Disease: Herring lateral pillar classification predicts prognosis.
• Developmental Dysplasia of the Hip (DDH): Graf ultrasound classification in infants.
• Neoplastic lesions: Enneking staging for musculoskeletal tumors.

Current Gold Standard Treatment

Non-operative

• Observation and activity modification for mild developmental conditions (e.g., idiopathic chondrolysis, early Perthes).
• NSAIDs and physical therapy for inflammatory and overuse syndromes.
• Antibiotics for infectious causes after culture confirmation.
• Orthotic bracing for DDH in infants.

Operative Indications and Treatment

• SCFE: Urgent in situ pinning to prevent progression and avascular necrosis.
• Fractures: Surgical fixation for displaced femoral neck or intertrochanteric fractures.
• Perthes disease: Femoral or pelvic osteotomies in advanced cases to improve containment.
• Neoplasms: Biopsy followed by oncologic resection and adjuvant therapy.
• Septic arthritis: Surgical drainage and intravenous antibiotics.
• Developmental dysplasia: Closed or open reduction and pelvic/femoral osteotomies if bracing fails.

Modern Complications & Outcomes

Complications

Outcomes

• Early diagnosis and treatment correlate with improved pain control and function.
• SCFE stable forms have excellent outcomes with timely pinning.
• Perthes prognosis depends on age and lateral pillar classification.
• Infectious causes require prompt intervention to prevent joint damage.
• Developmental dysplasia outcomes improved with early screening and treatment.

Classic Clinical Notes

Differential Diagnosis of Unilateral Hip Pain

Congenital

• Congenital coxa vara (probably not painful until later)
• Proximal femoral focal deficiency

Traumatic

• Slip capital femoral epiphysis
• Femoral neck, intertrochanteric fracture or stress fracture
• Lesser trochanter (LT) or greater trochanter (GT) avulsions, anterior superior iliac spine (ASIS) avulsion
• Ischial, pubic, ilium fractures

Developmental

• Dislocation/dysplasia (probably not painful quite as yet, but may be)
• Developmental coxa vara
• Idiopathic chondrolysis

Vascular

• Perthes disease
• Post-traumatic
• Sickle cell, Gaucher’s, or idiopathic osteonecrosis

Inflammatory

• Toxic synovitis, bursitis, osteitis
• Juvenile rheumatoid arthritis
• Other seronegative spondyloarthropathies – Reiter’s, psoriatic, ankylosing spondylitis

Neoplastic

• Benign – Unicameral bone cyst (UBC), aneurysmal bone cyst (ABC), eosinophilic granuloma (EG), chondroblastoma, osteoid osteoma, osteoblastoma, fibrous dysplasia, giant cell tumor (GCT) (a bit young for this)
• Malignant – osteosarcoma, Ewing’s sarcoma, leukemia/lymphoma

Infectious

• Septic arthritis
• Proximal femoral osteomyelitis
• Psoas abscess

Metabolic

• Rickets?

Last Updated on January 25, 2026 by orthonet