Periprosthetic joint infection of shoulder arthroplasties

Periprosthetic joint infection of shoulder arthroplasties is one of the most common reasons for post-operative revision surgery. Propionibacterium acnes is the most commonly associated organism.

Epidemiology

The mean incidence has been reported to be ~1%; although after reverse total shoulder arthroplasty, the incidence is ~4% and can reach up to 10% in the subgroup of young male patients operated on with a reverse prosthesis ¹.

Risk factors

Males are ~2.5x increased risk for infection compared to females, and reverse total shoulder arthroplasty is associated with a ~6x increased risk of infection over anatomic total shoulder arthroplasty. Trauma-associated prostheses are associated with a 3x increased risk of infection ¹.

Risk factors associated with periprosthetic shoulder infections are ¹:

• post-traumatic osteoarthritis

• previous surgery

• repeated cortisone injections

• systemic corticosteroid treatment and other immunosuppressive medicaments

• rheumatoid arthritis

• diabetes mellitus

Clinical presentation

Any pain, stiffness, and/or shoulder prosthesis loosening should be considered as potential infection ¹.

Early periprosthetic infections (up to 3 months post-operative) and acute hematogenous infections are usually associated with local and systemic signs of inflammation ¹:

• local signs (e.g. redness, heat) are not always obvious due to the amount of overlying soft tissue

• systemic signs: increased serum CRP and synovial fluid leukocyte counts (usually >10,000/μL)

In late periprosthetic infections, the local and systemic signs of inflammation are absent so the clinical diagnosis is more difficult to make ¹.

Pathology

Staphylococcus spp. and P. acnes are most commonly associated with periprosthetic shoulder infections, with the latter most commonly being associated with ~50% (range 31-70%), perhaps due to proximity to the axilla ¹.

Radiographic features

Plain radiograph

Early implant loosening or osteolyses ¹.

CT and MRI

For visualizing abscess formations ¹.

Nuclear medicine

Scintigraphy

White cell labeled-scintigraphy does not have higher sensitivity and specificity ¹.

PET

For visualizing abscess formations ¹.

Treatment and prognosis

• early infections: radical surgical debridement of the periprosthetic tissue and radical synovectomy with a one-stage prosthesis inlay exchange ¹

• late Infections: antibiotics, soft tissue debridement with sine-sine resection arthroplasty, a permanent spacer, and/or one-stage or two-stage septic revision ¹

• antibiotic joint spacer: implantation of antibiotic joint spacer after removal of the infected prosthesis results in much better joint function; the spacer preserves arm length to help preserve soft tissues resulting in better function ¹

See also

• reverse total shoulder arthroplasty (RTSA)

• total shoulder arthroplasty (TSA)