A Rare Case of Staphylococcus Caprae Periprosthetic Hip Infection with Unusual Clinical Presentation

Total hip arthroplasty (THA) surgeries are rapidly increasing due to an aging population, leading to an increase in degenerative hip osteoarthritis. However, 1% of these patients go through prosthetic joint infection (PJI), which gives rise to implant failure with prolonged periods of patient incapacitation and higher mortality risk.

In this article, we report an unusual case of a 62-year-old male who developed a PJI 7 months after a THA. The patient complained of groin, buttock pain, and swelling. He underwent MRI examination, which revealed the presence of a voluminous three-lobed formation with liquid content located around the prosthesis. After several attempts where microbiological samples reported negative results, a microbiological sample came out positive for Staphylococcus Caprae at the time of femoral component sonication. S. caprae is a Gram-positive bacillus belonging to the Staphylococcus spp. It is most commonly found as a commensal in goats and sheep, but it is a rare pathogen in human infections. The patient underwent two-stage revision surgery, resulting in the total resolution of the infection.

Staphylococcus Caprae still remains an unusual cause of infection. We report the 11th hip PJI due to S. caprae successfully treated with a two-stage exchange protocol.