Single-use instrumentation, cutting blocks, and trials decrease contamination during total knee arthroplasty: a prospective comparison of navigated and nonnavigated cases.

The purpose of this prospective controlled trial was to determine whether decrease in contamination could be achieved in nonnavigated and navigated total knee arthroplasties by replacing traditional saws, cutting blocks, and trials with specialized saws and single-use cutting blocks and trials. Various tray wrapping metrics during total knee arthroplasty were measured in 400 procedures performed by 8 different surgeons at 6 institutions. Instrumentation contamination was determined by counting the number of tray sterility indicators, pans, and instruments that were compromised. The results show that a decrease in contamination was evident in 57% (nonnavigated) and 32% (navigated) fewer compromises of tray sterility indicators, pans, and instruments. Single-use instruments show promising benefits, but further study is needed to confirm safety and efficacy before they can be widely adopted. The authors believe that the use of single-use instruments, cutting guides, and trial implants for total knee arthroplasty will play an increasing role in decreasing operating room contamination and potential deep infections.

Contemporary unicompartmental knee arthroplasty: fixed vs mobile bearing.

Contemporary unicompartmental knee arthroplasty has shown resurgence in use partly because of studies reporting excellent long-term survivorship. Both fixed-bearing as well as mobile-bearing designs have shown comparable results. Fixed-bearing designs, in particular, implants with metal-backed tibial components have shown more consistent long-term survival, whereas fixed bearings with an all-polyethylene tibial component have had mixed results. Similar to the all-polyethylene tibial component designs, mobile-bearing designs have demonstrated mixed results. One concern with mobile bearings is the high rate of complete tibial radiolucent lines. The keys to long-term survival of both fixed and mobile-bearing designs in unicompartmental knee arthroplasty are patient selection, surgical technique, and surgical experience.

Navigation did not improve the precision of minimally invasive knee arthroplasty.

UNLABELLED: Potential advantages of minimally invasive total knee arthroplasty (TKA) include decreased pain, faster recovery, and increased quadriceps muscle strength. Computer-assisted navigation has been associated with more accurate component alignment. We evaluated two groups of 50 patients who had minimally invasive TKAs performed with and without navigation by two surgeons. A comparison of 50 previous TKAs by each of the two surgeons showed similar results. The mean operative times for the navigation and nonnavigation groups were 112 minutes (range, 63-297 minutes) and 54 minutes (range, 35-86 minutes), respectively. The mean estimated blood losses, mean Knee Society pain as well as functional scores and mean component alignments were similar. The number of knees that deviated by more than 3 degrees from the normal anatomic axis was three and one in the navigated and nonnavigated groups, respectively. Complication rates were 6% and 4% in the navigated and nonnavigated groups, respectively. Our data demonstrate no distinct advantage of navigation when combined with a minimally invasive approach. LEVEL OF EVIDENCE: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.