Background: Two-stage revision is known as the gold-standard method for knee prosthetic joint infection (PJI), but the most suitable treatment method remains controversial. Typically, weight-bearing is restricted during the interval between the stages. The aim of this study was to evaluate the clinical outcomes of unrestricted weight bearing with cement spacers fabricated using the Knee Articulating Spacer Mold (KASM®; Ortho Development Corporation, Draper, UT, USA) for knee PJI.
Methods: We retrospectively reviewed 16 patients who underwent two-stage revision surgery for knee PJI between April 2015 and March 2020. The procedure involved the removal of the infected prosthetic joints and the insertion of cement spacers made using KASM®. The evaluation focused on the possibility of full-weight bearing gait during the interval between the first and second stages, surgical time, blood loss, complications, and postoperative outcomes, including the Knee Society Score (KSS), Knee Society Function Score, and range of motion (ROM).
Results: All patients were able to walk with full weight-bearing. However, cement spacer dislocation occurred in one patient (6.3%). During the interval between stages, infection occurred in one patient (6.3%) and debridement was performed. Average interval between the stages was 92.7 days (range, 55-166 days). After the reimplantation, reinfection occurred in two patients (12.5%) out of the 16. Among the 14 patients with successful reimplantation, the average operative time was 116.1 min (range, 76-153 min) and the average perioperative blood loss was 476.1 mL (range, 89.5-859 mL). The KSS was 86.4 (range, 62-100), the Knee Society Function Score was 73.6 (range, 45-100), and flexion ROM was 111.8° (range, 95°-130°) at the latest follow-up. The mean follow-up period was 871 days (range, 117-1103 days).
Conclusions: Unrestricted weight-bearing gait using cement spacers during the waiting period for two-stage revision surgery for knee PJI led to favorable outcomes in this case series, which lacked a control group. Further studies are needed to assess whether the benefits of weight-bearing outweigh the risks and improve overall outcomes.
Keywords: articulating spacer; full weight-bearing; prosthetic joint infection; total knee arthroplasty; two-stage revision.
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