Antibiotic-loaded articulating cement spacers in two-stage revision for infected total knee arthroplasty: individual antibiotic treatment and early results of 21 cases.

OBJECTIVE

To detail our early experience and technique of a modified two-stage reimplantation protocol using antibiotic-loaded articulating cement spacers (ALACSs) for treatment of late periprosthetic infection after total knee arthroplasty (TKA).

METHODS

From January 2006 to February 2009, a series of 21 patients (21 knees) with late infected TKAs were treated by radical debridement and removal of all components and cement, and then articulating spacers were implanted using antibiotic-impregnated bone cement. For this purpose, 4 g vancomycin powder was mixed with per 40 g cement. Graduated knee motion and partial weight bearing activity were encouraged in the interval period. Each patient received an individual systemic organism-sensitive antimicrobial therapy for 4.9 (range, 2-8) weeks followed by a second-stage TKA revision. All the patients were regularly followed up using the American Knee Society Scoring System.

RESULTS

Each case underwent a successful two-stage exchange and had infection eradicated, none had recurrent infection after an average of 32.2 (range, 17-54) months of follow-up. Preoperatively, the mean knee score was 53.5 points, function score was 27.3 points, pain score was 25.7 points, range of motion (ROM) was 82.0 degree extensor lag was 2 degree Between stages, the mean knee score was increased to 61.3 points, function score to 45 points, pain score to 35 points, ROM to 88.2 degree and extensor lag to 3.4 degree At final follow-up, the mean knee score was further increased to 82.1 points, function score to 74.5 points, pain score to 42.1 points, ROM to 94.3 degree and knee extension lag to 1.9 degree The interval period was 11.5 (range, 6-32) weeks. The amount of bone loss was unchanged between stages. No patient developed noticeable dysfunction of the liver or kidney or other complications such as impaired wound healing, deep venous thrombosis, pulmonary embolism, cerebrovascular accidents, etc.

CONCLUSIONS

Treating infected TKA with ALACS avoids spacer-related bone loss, preserves knee function between stages, and eradicates infection effectively without significant complications. The early clinical results are inspiring. The authors believe that radical and repeated (if needed) debridement, individual application of systemic antibiotics, and reasonable timing judgement upon the secondary revision are all key factors related to a successful outcome with two-stage reimplantation procedure for infected TKA.