SLR - January 2013 - Townson
Reference: Kessler B, Sendi P, Graber P, Knupp M, Zwicky L, Hintermann B, Zimmerli W. Risk Factors for Periprosthetic Ankle Joint Infection: A Case-Control Study. J Bone Joint Surg Am. 2012; 94: 1871-6.
Scientific Literature Review
Reviewed by: James Townson, DPM
Residency Program: DVA- New Mexico Healthcare System
Podiatric Relevance:
The use of total ankle arthroplasty is becoming more prevalent within the field of foot and ankle surgery. There are several complications associated with this procedure, with implant failure and infection being the most common. Newer designs and improved surgical technique have led to the decrease in mechanical failure. However, infection remains a devastating complication that can lead to implant failure, amputation or death.
Methods:
Using a computerized cohort database, 408 patients were identified who had undergone total ankle arthroplasty. A case was identified as a patient who was treated for a periprosthetic joint infection. Only first occurrences were counted as a case. The infections were categorized as exogenous or hematogenous. Two controls were formed; one was an age- and sex-matched control, while the other was a time-matched control. Patient-related variable risk factors were recorded. Potential risk factors for the development of periprosthetic joint infection were divided into four categories: (1) the indication for total ankle arthroplasty, (2) clinical characteristics prior to the index surgery, (3) characteristics of the index surgery itself, and (4) the postoperative course after the index surgery. Indication-associated variables included primary osteoarthritis, rheumatoid arthritis, posttraumatic arthritis, and a preexisting ankle arthrodesis. Visual analog score, ankle range of motion and AOFAS hindfoot score were recorded for preoperative clinical factors. The duration and index surgery were also considered risk factors.
Results:
Twenty-six infections were identified with 22 (85 percent) being exogenous and four (15 percent) being hematogenous. Staphlococcus aureus was identified as the most common pathogen. Patient-related variables were similar in rates of infection for the case and control groups with the exception of corticosteroid use. Corticosteroid use was similar in the case group compared to the age- and sex-matched control for cause of infection but came out to be statistically significant less in the time-matched control. Statistically higher infections occurred in the case group compared to both control groups for the following: (1) revision of a preexisting ankle arthrodesis, (2) prior surgery at site of infection, A (3) lower preoperative AOFAS hindfoot score, (4) greater duration of surgery, (5) revision total ankle arthroplasty, (6) persistent wound dehiscence (≥14 days), and (7) secondary wound drainage. Total ankle arthroplasty without subtalar joint arthrodesis was statistically less likely to lead to a periprosthetic infection.
Conclusion:
The authors found in this case-control study that patients undergoing total ankle arthroplasty are at higher risk for a periprosthetic infection if the procedure is a revision of a preexisting ankle arthrodesis, has had prior surgery at the site, has a lower preoperative AOFAS hindfoot score, has a prolonged surgery time, is a revision of total ankle arthroplasty, and has a persistent wound dehisance or secondary wound drainage.