Obturator Internus Abscess with Ipsilateral Septic Hip Arthritis

Area of Science:

• Orthopedic Surgery
• Pediatric Infectious Diseases
• Musculoskeletal Imaging

Background:

• Obturator internus muscle (OIM) abscess is a rare condition often misdiagnosed as septic arthritis of the hip.
• Deep pelvic location of OIM abscess complicates surgical drainage, leading to reliance on antibiotics or aspiration.
• Concurrent OIM abscess and septic hip present significant diagnostic and therapeutic challenges.

Observation:

• A 12-year-old boy presented with OIM abscess, ipsilateral pyogenic hip arthritis, and acute osteomyelitis of the acetabular triradiate cartilage.
• The causative organism was identified as Staphylococcus aureus, sensitive to oxacillin.
• The patient's complex condition was successfully managed through surgical drainage and irrigation.

Findings:

• Surgical drainage of the OIM abscess via the Stoppa approach combined with arthroscopic irrigation of the hip joint proved effective.
• This combined approach addressed both the deep-seated abscess and the associated joint infection and bone inflammation.
• Successful treatment avoided prolonged antibiotic therapy, which is often necessary with inadequate drainage.

Implications:

• The Stoppa approach offers a viable surgical option for deep pelvic OIM abscesses, even when complicated by hip joint sepsis and osteomyelitis.
• This case highlights the importance of considering OIM abscess in pediatric patients with hip pain and fever, especially when initial treatments fail.
• Effective surgical management can lead to better outcomes and potentially shorter treatment durations compared to non-operative methods.