Two-stage approach to primary TKA in infected arthritic knees using intraoperatively molded articulating cement spacers

Abstract

Background: The treatment of knee arthritis with coexistent bone or joint sepsis is challenging. Despite the condition causing considerable morbidity, there is no generally agreed-upon approach to its treatment.

Description of technique: We used aggressive débridement of the knee and implantation of intraoperatively molded articulating antibiotic cement spacers with 4 g vancomycin and 2 g streptomycin per bag of cement for patients with unknown organisms as a first stage. When the infecting organism was known, organism-specific antibiotics were used. For fungal infections, 400 mg amphotericin B was added per bag of cement. This was followed by TKA as a second stage once soft tissues had healed 2 to 29 months later, (mean, 6 months) and return of laboratory parameters to within a normal range. One patient underwent two débridement and spacer procedures for suspected persistent infection.

Methods: To determine whether this approach resulted in adequate control of infection and satisfactory scores for pain and function, we retrospectively reviewed 15 patients who presented with infected arthritic knees between 2001 and 2009; all patients with infected arthritic knees were treated with this same technique during this period. We assessed knee ROM, Knee Society scores, WOMAC scores, and VAS scores preoperatively and during followup. Followup was at a mean of 4 years (range, 2-7 years); No patient was lost to followup before 2 years.

Results: Two of the 15 patients were comfortable with the spacers and declined a more definitive reconstruction, and no patient had a recurrent infection after TKA. Before spacer placement, the mean ROM was 103.° (range, 60°-150°), with the spacers in place it decreased to a mean 87° (range, 60°-135°), and after TKA it improved to a mean of 115° (range, 75°-150°). The mean Knee Society Knee and Function scores progressed from 41 and 43 preoperatively to 85 and 83 at latest followup, respectively. The WOMAC scores improved from 51 initially to 18 after TKA. The mean VAS scores improved from 66 preoperatively to 18 after the TKA.

Conclusions: In this small proof-of-concept series, we found that joint débridement and use of intraoperatively molded articulating antibiotic cement spacers as part of a staged approach to treat the infected arthritic knee before TKA resulted in infection control in all patients at a minimum of 2 years' followup, reduction of knee pain, and restoration of knee function. We suggest that larger, comparative series be performed to further validate these results.

Figures

Fig. 1

An intraoperative view of a knee before débridement shows grossly infected synovium and necrotic bone.

Fig. 2

An intraoperative view shows the knee after débridement and femoral and tibial resection.

Fig. 3

An intraoperative view shows the antibiotic-impregnated articulating cement spacers in situ with the knee in flexion. The flexion gap has been kept loose to facilitate postoperative flexion.

Fig. 4A–B

(A) A postoperative AP view shows the complete coverage of the femoral and tibial condyles by the articulating spacers. (B) A postoperative lateral view shows the stability and congruence of the spacers.

Fig. 5A–C

(A) A preoperative AP radiograph shows advanced arthritis, subchondral bone destruction, and soft tissue swelling. The preoperative (B) lateral radiograph shows irregular destruction of bone, and the (C) MR image shows irregular destruction of subchondral bone with increased signal intensity of the surrounding tissues.