CASE 104

By: Dr. Nizar Al-Nakshabandi MD, FRCPC

HISTORY: 71-year-old male with bilateral hip pain.

What are your findings?

What is the differential diagnosis?

What are the causes?

FINDINGS:

The AP radiograph of the pelvis with bilateral frog-leg views demonstrate intrapelvic displacement of the medial wall of the acetabulum.

DIAGNOSIS:

Protrusio acetabuli.

PEARLS AND DISCUSSION:

Mnemonic:

My PROTRUSIO

The complete list:

·         My: Marfan syndrome.

·         P: Paget disease and primary protrusio acetabuli.

·         R: Rheumatoid arthritis.

·         O: Osteogenesis imperfecta.

·         T: Trauma (rarely: tumour locally, or tumour causing osteomalacia).

·         R: Rickets.

·         U: Unknown (idiopathic).

·         S: (P)soriatic arthritis (rarely: sickle cell anaemia).

·         I: Inflammatory arthritis (ankylosing spondylitis) (rarely: infection).

·         O: Osteomalacia.

FURTHER READING:

1.      Kuhlman JE, Scott WW, Fishman EK et-al. Acetabular protrusion in the Marfan syndrome. Radiology. 1987;164 (2): 415-7. Radiology (abstract) - Pubmed citation

2.      Van De Velde S, Fillman R, Yandow S. The aetiology of protrusio acetabuli. Literature review from 1824 to 2006. Acta Orthop Belg. 2007;72 (5): 524-9. Pubmed citation

3.      McBride MT, Muldoon MP, Santore RF et-al. Protrusio acetabuli: diagnosis and treatment. J Am Acad Orthop Surg. 2001;9 (2): 79-88.