What is the recommended treatment for a 49-year-old female with an avulsion fracture of the anterior inferior iliac spine presenting with upper thigh pain?

Treatment of Avulsion Fracture of the Anterior Inferior Iliac Spine in a 49-Year-Old Female

Conservative management with rest, analgesia, and early mobilization is the recommended treatment for this patient, as most anterior inferior iliac spine (AIIS) avulsion fractures in adults heal successfully without surgery unless there is significant displacement (>2 cm) or symptomatic nonunion. 1

Initial Pain Management

• Start acetaminophen as first-line analgesia to control acute pain, avoiding NSAIDs if cardiovascular or renal comorbidities exist 2
• Consider short-term narcotic medications only if necessary for severe pain that is not controlled with acetaminophen 2
• Avoid prolonged bed rest as it accelerates bone loss, muscle weakness, and increases risk of deep vein thrombosis and pressure ulcers 2, 3

Conservative Treatment Protocol

• Implement rest and avoid activities that stress the rectus femoris muscle (which attaches to the AIIS), as this is the primary conservative approach for most pelvic avulsion fractures 1
• Begin range-of-motion exercises within the first few days to prevent stiffness and maintain joint mobility 2, 3
• Initiate early mobilization as tolerated to prevent complications of immobility while respecting pain limits 2

Rehabilitation Strategy

• Implement early post-fracture physical training and muscle strengthening once acute pain subsides, typically within 2-4 weeks 2
• Progress to weight-bearing exercises and sport-specific training gradually over 8-12 weeks 1
• Establish long-term balance training and fall prevention programs to reduce future injury risk 2

Indications for Surgical Intervention

Surgery should be considered if:

• Fracture displacement exceeds 2 cm, as widely displaced fractures have poorer outcomes with conservative treatment 1, 4
• Symptomatic nonunion develops after 3-4 months of conservative management 1, 5
• The patient requires rapid return to high-level athletic activity, as operative treatment shortens rehabilitation time 6
• Exostosis formation or heterotopic ossification causes persistent symptoms 5, 4

Surgical Approach When Indicated

• Open reduction and internal fixation is the procedure of choice for significantly displaced fractures, allowing earlier return to activity 6, 4
• Excision of the avulsed fragment may be performed for chronic symptomatic cases or missed diagnoses with exostosis formation 5, 4
• Be aware that heterotopic ossification can occur following surgical treatment and may require subsequent excision 5

Critical Pitfalls to Avoid

• Do not miss the diagnosis on initial radiographs—AIIS avulsions are relatively rare and require high clinical suspicion, especially in patients presenting with anterior hip or upper thigh pain 4
• Do not allow prolonged immobilization beyond what is necessary for acute pain control, as this delays recovery 2
• Do not assume all pelvic avulsions require surgery—most heal well with conservative treatment unless significantly displaced 1
• Be alert for atypical presentations such as meralgia paresthetica (lateral femoral cutaneous nerve compression), which can occur with anterior superior iliac spine avulsions 7

Expected Outcomes

• With appropriate conservative treatment, most patients return to their previous activity level within 8-12 weeks 1
• Functional results are generally good with both conservative and operative treatment, though operative treatment may shorten rehabilitation time in selected cases 6
• Young athletes frequently return to the same level of sport with proper management 1