Intraoperative molds to create an articulating spacer for the infected knee arthroplasty.
BACKGROUND
Chronic infections in TKA have been traditionally treated with a two-stage protocol incorporating a temporary antibiotic-loaded cement spacer. The use of a static as opposed to an articulating spacer is controversial. Some surgeons believe a static spacer results in a higher rate of infection eradication, whereas others believe an articulating spacer provides equivalent rates of infection control with improved function between stages and the potential for better eventual range of motion.


OBJECTIVE
We determined the rates of infection control and postoperative function for an articulating all-cement antibiotic spacer fashioned intraoperatively from prefabricated silicone molds.


METHODS
We retrospectively reviewed 60 patients with an infected TKA using the same cement-on-cement articulating spacer. A minimum of 4 g antibiotic per package of cement was used when making the spacer. Complications and pre- and postoperative knee flexion, extension, and Knee Society scores were recorded. Bone loss associated with the spacer was determined radiographically and by intraoperative inspection of the bony surfaces at the second stage. Minimum followup was 24 months (mean, 35 months; range, 24-51 months).


RESULTS
Seven patients (12%) became reinfected, four with an organism different from that identified at the index resection arthroplasty. One spacer femoral component broke between stages but did not require any specific treatment. We identified no bone loss between stages and no complications related to the cement-on-cement articulation. The mean pretreatment Knee Society scores of 53 improved to 79. The mean preoperative flexion of 90.6º improved to 101.3º at final followup.


CONCLUSIONS
An articulating antibiotic spacer was associated with control of a deep periprosthetic infection in 88% of patients while allowing range of motion between stages.


METHODS
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
Rush University Medical Center, 1611 West Harrison Street, Suite 300, Chicago, IL 60612, USA.
Geoffrey S
GS
Van Thiel
Keith R
KR
Berend
Gregg R
GR
Klein
Alexander C
AC
Gordon
Adolph V
AV
Lombardi
Craig J
CJ
Della Valle
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000295:instrumentation; D001843:Bone Cements / Q000627:therapeutic use*; D020099:Coated Materials, Biocompatible; D003646:Debridement; D020878:Device Removal; D005260:Female; D006801:Humans; D017053:Infection Control / Q000379:methods*; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000382:microbiology / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging / Q000382:microbiology / Q000628:therapy*; D011859:Radiography; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D012828:Silicones; D013997:Time Factors; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D001843:Bone Cements; D020099:Coated Materials, Biocompatible; D012828:Silicones