Background

Staphylococcus epidermidis is one of the main organisms associated with prosthetic joint infections. One of the major pathogenic attributes of this organism is the ability to form biofilms, making it extremely resistant to currently available antimicrobial therapies. There is, therefore, an urgent requirement for novel agents that are effective against this organism. Antimicrobial peptides represent a novel group of agents that show good activity towards biofilm-forming S. epidermidis. Antimicrobial peptides are particularly interesting due to their multiple modes of action which are thought to reduce the rate of resistance development to the agents.

Fifty-seven revision total knee arthroplasties were performed in our hospital using the TC3 system between 1995 and 1997. Twelve patients died. Forty-five patients were followed up for an average of 5.6 years (range 4 – 7 years). No patients were lost to follow-up.

All patients were clinically and radiologically evaluated. A postal patient satisfaction questionnaire was completed. Two patients were revised; one for infection and one for instability. Survivorship using revision as the end point was 93.3% at 7 years.

Indications for revision were infection(4;9%), instability(38;84%), pain and stiffness(3;7%). 32(71%) patients were satisfied with their outcome, 7(16%) were non-committal and 6(13%) were disappointed at 5 years. We have analysed the 13 dissatisfied patients and highlight the lessons learnt.

Pain and stiffness are not good indications for revision.

We suggest the above lessons we have learnt from our initial revision arthroplasty learning curve may correlate to the clinical outcome of this small group of dis-satisfied patients.