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.

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.

Summary Single use instrumentation had a significant reduction on OR Turnover time and instrument setup/clean up time compared to traditional instrumentation. Introduction Recently, focus has shifted to improving OR efficiency by surgeons and hospital admin. The purpose of this study was to determine the effect of traditional instrumentation vs. single use instrumentation (SUI) on OR efficiency in navigated primary TKA. Methods This prospective randomized study was conducted at a single center, community hospital by a single surgeon. Patients were split into two groups: Group 1 (Navigated Traditional (n=23)) and Group 2 (Navigated SUI (n=26)). Efficiency was examined by measuring specific time intervals based on milestones in the OR preparation, surgical procedure, and OR cleanup. Results Instrument set up time was reduced by an average of 8.5 minutes (min) in Group2 vs. Group1 (p=0.00). Patient set up took slightly longer in Group2 (1.47 min) but not statistically significant (p=0.50). Both groups had similar procedure time (p= 0.21) and patient OR Time (120 min for both groups p=0.93). Instrument clean up time was significantly shorter in Group 2 (difference 3.44 min (p=0.01). Overall surgical episode was significantly faster in the Group 2 by 9.57 min (p=0.02). Tourniquet time significantly reduced in the Group 2 by 4.92 min (p=0.02). Overall Instrument set up and clean up was faster by 11.94 min in Group 2 vs. Group 1. Notably, the OR turnover time was reduced by 23.52 min in the Group 2 vs. Group 1. Conclusion Single-use instruments had a significant reduction on OR Turnover time and instrument setup/cleanup time compared to traditional instrumentation. A larger prospective trial is warranted.

In 72 knees, revision total knee arthroplasties were comparable in results with primary operations. There was a higher incidence of extensor mechanism problems and less complete relief of pain. Although the incidence of postoperative radiolucencies was high, these were nonprogressive and, in most cases, not harbingers of progressive loosening. Revision surgery requires surgical skill and judgment, as well as facilities to provide a wide range of prosthetic sizes and, if necessary, custom designs.

Computer-navigated and minimally invasive TKAs are emerging technologies that have distinct strengths and weaknesses. We compared duration of surgery, length of hospitalization, Knee Society scores, radiographic alignments, and complications in two unselected groups of 81 consecutive knees that underwent TKA using either a minimally invasive approach or computer navigation. The two groups were operated on by two different surgeons over differing timeframes. The mean surgical time was longer in the navigated group by 63 minutes. The Knee Society scores and lengths of hospitalization of the two groups were similar. The postoperative component alignments of the two groups were similar; the mean femoral valgus and tibial varus angles of the navigation group changed from 96° and 88° preoperatively to 95° and 89° postoperatively, respectively, and in the minimally invasive group, the mean femoral valgus angles and tibial varus angles changed from 97° and 88° preoperatively to 95° and 89° postoperatively, respectively. There were 11 major and three minor complications in the navigation group, including one revision, two femoral shaft fractures, four reoperations for knee stiffness, and four instances of bleeding from tracker sites. We believe the higher incidence of complications in addition to the longer operative time in the navigated group may outweigh any potential radiographic benefits. Level of Evidence: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Computer-assisted navigation is a surgical tool that may decrease malalignment outliers in TKA. With any new surgical technique, there is the possibility of unexpected complications that raise caution. We report two patients with displaced femoral fractures at optical tracker pin placement sites created for routine performance of navigated TKA. Our experience suggests single bicortical 5-mm pins placed in the femoral shaft have the added risk of creating a stress riser leading to the potential for fracture. Females may have a higher risk for this complication. We believe bicortical pin fixation in the femur or tibia no longer is indicated.

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.

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° 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.

INSALL, JOHN N. M.D.*; DETHMERS, DANIEL A. M.D.Editor(s): CRACCHIOLO, ANDREA III M.D. Author Information