505 - A Case of External Femoral Vascular Compression by an Enlarging Iliopsoas Bursitis Following Total Hip Arthroplasty

Case Diagnosis: Iliopsoas bursitis resulting in compression of the femoral vasculature

Case Description: A 64-year-old female with a history of chronic hip pain in the setting of prior right total hip arthroplasty (THA) presented to an outpatient musculoskeletal clinic with two months of new-onset right lower extremity edema and pain. Physical examination showed venous stasis changes, 2+ pitting edema to the knee, and palpable pedal pulses. Hip provocative maneuvers elicited pain, but neuromuscular exam was intact. Computed tomography (CT) scan taken 2-years before the onset of lower extremity edema showed a large right iliopsoas bursal fluid collection (8.2 x 8.5 x 14.0 cm). Fluoroscopic attempt of bursal aspiration at that time was inconclusive. Repeat CT scan demonstrated an enlarged collection (9.5 x 9.1 x 16.4 cm) with external compression on the right common femoral artery and vein. Additional work-up including CBC, venous ultrasound, and D-dimer showed no evidence of infection or deep venous thrombosis.

Discussions: Iliopsoas bursitis is commonly caused by arthritis, trauma, gout, or infection; however, these are unlikely to cause mass effect and vascular compression as seen in this patient. Few case reports have previously cited iliopsoas bursitis as a known complication following THA with a possible mechanism that includes mechanical irritation of the iliopsoas bursa from the prosthetic components. Given the chronicity of our patient's slowly expanding fluid collection near the site of her prior THA, follow-up with orthopedic surgery was recommended for tissue biopsy. Lymphatic compression was also considered, and this patient was referred for lymphedema therapy.

Conclusions: Iliopsoas bursitis is a rare complication following THA that should be considered in patients presenting with unilateral lower extremity edema. Early recognition and treatment could prevent additional complications and reduce potential co-morbidities involving the femoral neurovascular bundle.