- diagnosis of septic loosening is initially based on history, x-ray findings, and elevated sed rate;
- clincially patients may note increasing pain at both rest and with activity;
- despite the variety of tests available, it may be difficult to distinguish aseptic loosening (acetabular and femoral) from
an infected THR;
- risk factors:
- Methods to Prevent Infection
- references: Perioperative factors associated with septic arthritis after arthroplasty. Prospective multicenter study of 362 knee
and 2,651 hip operations.
- type I: early postoperative
- type II: late chronic (two-stage revision arthroplasty)
- type III: acute hematogenous (such as from dental procedures)
- type IV: positive intraoperative cultures with clinically unapparent infection
- Prosthetic joint infection diagnosed postoperatively by intraoperative culture.
- classic findings include, irregular or scalloped border on the endosteal surface of the cortex, marked periosteal reaction,
or late dislocation;
- dx of THR infection that is difficult to appreciate grossly is often delayed, especially in a patient w/o fever or severe pain;
- x-ray signs of loosening of prosthesis are seen in 2/3 of late infections, but in less than 50 % of early infections;
- arthrography: (see: hip aspiration)
- may be helpful for determining loosening of cemented acetabular components by showing penetration of dye between
cement and bone;
- note that a fibrous membrane between cement and bone will impede penetration of cement (false negative);
- bone scans in THR:
- Evaluation of musculoskeletal sepsis with indium-111 white blood cell imaging.
- Asymptomatic total hip prosthesis: Natural history determined using Tc-99MDP bone scans.
- Laboratory Evaluation and Aspiration:
- currently staph epidermidis has emerged as the most common infectious organism followed closely by staph aureus;
- above two bacterial species along with pseudomonas are slime producers (glycocalyx) which makes them particularly
resistant to treatment w/ antibiotics;
- gram negative organisms which do not produce a glycocalyx may not be as virulent as previously thought;
- consider need for Ziehl Nielsen stains, mycobacterial cultures, and fungal cultures;
- Methicillin-resistant Staphylococcus epidermidis in infection of hip arthroplasties.
- Deep infection of cemented total hip arthroplasties caused by coagulase negative staphylococci.
- Total Hip Arthroplasty Infection With Chlamydia Pneumoniae and Mycobacterium Chelonae
- Management: (see revision THR);
- debridement and retension of components: (Tsukayama (1996))
- Infection after total hip arthroplasty. A study of the treatment of one hundred and six infections.
- one stage replantation:
- two stage replantation:
- antibiotic suppression:
- success rate of 20-30%;
- antibiotic treatment will not eliminate chronic deep infection about prosthesis;
- antibiotic management can be used as suppressive treatment for established infection.
- antibiotic suppression can be used if the following are met:
- prosthesis removal is not feasible (pt not candidate for anesthesia)
- microorganism is of low virulence & susceptible to antibiotics;
- patient can tolerate antibiotic w/o serious toxicity;
- prosthesis is not loose;
- ref: Conservative treatment of staphylococcal prosthetic joint infections in elderly patients
- girdlestone arthroplasty
Total Arthroplasty and the Veterans Administration--Symposium: Total Hip Arthroplasty: Infections at the Site of a Hip Implant Successful and Unsuccessful Management.