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Background: A classification system with four types of infected TKAs has been commonly used to determine treatment, especially with regard to whether the prosthesis should be removed or retained. Questions/purposes: We asked whether (1) the classification-dictated treatment of the four types of infection after TKA would control infection and maintain functional TKA; (2) repeated débridement and two-stage TKA would further improve the infection control rate after initial treatment; and (3) fixation of TKA prosthesis to the host bone was achieved. Methods: We retrospectively reviewed 114 patients with 116 infected TKAs. We determined the infection control rate after initial treatment, repeated débridement and two-stage TKA. We evaluated the functional and radiographic results using the Knee Society and Hospital for Special Surgery knee scoring systems. The minimum followup was 2 years (mean, 5.6 years; range, 2-8 years). Results: The overall infection control rate was 100% in all patients. All patients with early superficial postoperative infection, 94% of patients with early deep postoperative infection, 96% of patients with late chronic infection, and 86% of patients with acute hematogenous infection maintained functioning knee prosthesis at the final followup. One hundred nine of the 114 patients could walk with no or only slight pain and maintained functioning knee prostheses. These 109 patients had stable fixation of the TKA prosthesis to host bone. Conclusions: The techniques proposed by the classification effectively controlled infection and maintained functional TKA with firm fixation of the TKA prosthesis in most patients. Repeated débridement and two-stage TKA further improved the control of infection and functional TKA after initial treatment. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Periprosthetic osteolysis is an increasingly prevalent complication of TKA. To reduce the polyethylene wear and periprosthetic osteolysis, particularly in young patients, the design of the contemporary fixed-bearing TKAs has been modified and mobile-bearing TKAs have been introduced. Questions/purposes: We asked whether the prevalence of osteolysis would be less in well-functioning mobile-bearing TKAs than in well-functioning contemporary fixed-bearing TKAs in young patients. Patients and Methods: We compared 488 patients (894 knees) who received fixed-bearing knee prostheses with 445 patients (816 knees) who received mobile-bearing knee prostheses. There were 187 men and 301 women (mean age, 58.6 years; range, 33-65 years) in the fixed-bearing group and 167 men and 278 women (mean age, 55.7 years; range, 33-65 years) in the mobile-bearing group. The mean followup was 12.6 years (range, 10-17 years) in the fixed-bearing group and 12.9 years (range, 10-17 years) in the mobile-bearing group. Results: The incidence of osteolysis was 1.6% (14 of 894 knees) in the fixed-bearing group and 2.2% (18 of 816 knees) in the mobile-bearing group at the final review. The mean postoperative Knee Society knee and function scores were 92.9 points and 83.5 points, respectively, in the fixed-bearing group and 90.7 points and 83.8 points, respectively, in the mobile-bearing group. The revision rates were 3.7% (33 of 894 knees) in the fixed-bearing group and 2.7% (22 of 816 knees) in the mobile-bearing group. Conclusions: We found the incidence of osteolysis, rate of revision, and implant survivorship were similar between fixed-bearing and mobile-bearing TKAs in younger patients. Level of Evidence: Level III, therapeutic study. See the guidelines for authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Recently, much debate has focused on the effect of gender-specific total knee arthroplasty. The purpose of the present study was to compare clinical and radiographic results as well as femoral component fit in patients receiving either a standard posterior cruciate-substituting LPS-Flex or gender-specific posterior cruciate-substituting LPS-Flex total knee prosthesis. Methods: Sequential simultaneous bilateral total knee arthroplasty was performed for eighty-five patients (170 knees). Eighty-five women (mean age, 69.7 years) received a standard LPS-Flex prosthesis in one knee and a gender-specific LPS-Flex prosthesis in the contralateral knee. The mean duration of follow-up was 2.13 years. At each follow-up, the Knee Society score, the Hospital for Special Surgery knee score, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score, and radiographs were evaluated. The aspect ratio of the distal part of the femur was compared with those of the standard LPS-Flex prosthesis and the gender-specific LPS-Flex prosthesis. Results: The mean postoperative Knee Society scores (95.5 points in the standard implant group, compared with 96.5 points in the gender-specific implant group) and Hospital for Special Surgery knee scores (90.7 points in the standard implant group, compared with 91.2 points in the gender-specific implant group) were similar in both groups. The mean postoperative WOMAC score was 36.6 points. Postoperatively, the mean ranges of knee motion in the supine position (125° in the standard implant group, compared with 126° in the gender-specific implant group), patient satisfaction (8.3 points in the standard implant group, compared with 8.1 points in the gender-specific implant group), and radiographic results were similar in both groups. The femoral component in the standard implant group fit significantly better than that in the gender-specific implant group (p < 0.0001). Conclusions: The present study did not show any clinical benefits of a gender-specific LPS-Flex total knee prosthesis at the time of short-term follow-up. Longer follow-up is needed to determine whether there will be an advantage in terms of longer-term function. [ABSTRACT FROM AUTHOR]

Background: The main goals of total knee arthroplasty are pain relief and improvement in function and the range of motion. The purpose of this study was to compare the ranges of motion of the knees of patients treated with a standard posterior cruciate-retaining total knee prosthesis in one knee and a high-flexion posterior cruciate-retaining total knee prosthesis in the other. Methods: Fifty-four patients (mean age, 69.7 years) received a standard posterior cruciate-retaining total knee pros- thesis in one knee and a high-flexion posterior cruciate-retaining total knee prosthesis in the contralateral knee. Five patients were men, and forty-nine were women. At a mean of three years postoperatively, the patients were assessed clinically and radiographically with the knee-rating systems of the Knee Society and the Hospital for Special Surgery and with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Results: The mean postoperative Knee Society and Hospital for Special Surgery knee scores were 93.7 and 89 points, respectively, for the knees with a standard posterior cruciate-retaining prosthesis, and they were 93.9 and 90 points, respectively, for the knees with a high-flexion posterior cruciate-retaining prosthesis. The mean postoperative WOMAC score was 22 points. Postoperatively, the mean ranges of motion without and with weight-bearing were 131° (range, 900 to 150°) and 115° (range, 75° to 145°), respectively, in the knees with a standard prosthesis and 133° (range, 900 to 150°) and 118° (range, 750 to 145°), respectively, in those with a high-flexion prosthesis. Patient satisfaction and radiographic results were similar in the two groups. No knee had aseptic loosening, revision, or osteolysis. Conclusions: After a minimum duration of follow-up three years, we found no significant differences between the two groups with regard to the range of knee motion or the clinical or radiographic parameters. Level of Evidence: Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Although the design features of the high-flexion posterior cruciate-retaining and high-flexion posterior cruciate-substituting total knee prostheses reportedly improve the range of knee motion, a clinical comparison of both systems with regard to range of motion has not been reported, to our knowledge. The purpose of the present study was to compare the range of motion and functional outcome in knees receiving either a high-flexion posterior cruciate-retaining or a high-flexion posterior cruciate-substituting total knee prosthesis. Methods: Two hundred and fifty patients (mean age, 71.6 years) received a high-flexion posterior cruciate-retaining total knee prosthesis in one knee and a high-flexion posterior cruciate-substituting total knee prosthesis in the contralateral knee. Ten patients were men, and 240 were women. At the time of each follow-up (minimum duration of follow-up, two years; mean, 2.3 years), the patients were assessed clinically and radiographically with use of the knee-rating systems of the Knee Society and the Hospital for Special Surgery. In addition, each patient completed the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) questionnaire. Non-weight-bearing and weight-bearing ranges of knee motion were determined in both groups. Results: The mean postoperative Knee Society knee score was 94 points for the knees treated with a high-flexion cruciate-retaining prosthesis and 95 points for those treated with a high-flexion posterior cruciate-substituting prosthesis. The mean postoperative Hospital for Special Surgery knee score was 90 points for the knees that had been treated with a high-flexion posterior cruciate-retaining prosthesis and 91 points for those that had been treated with the high-flexion posterior cruciate-substituting prosthesis. At the time of the latest follow-up, the knees that had been treated with a high- flexion posterior cruciate-retaining prosthesis had a mean non-weight-bearing range of motion of 133° and a mean weight- bearing range of motion of 118°. The knees that had been treated with a high-flexion posterior cruciate-substituting prosthesis had a mean non-weight-bearing range of motion of 135° and a mean weight-bearing range of motion of 122°. No knee had aseptic loosening, revision, or osteolysis. Conclusions: After a minimum duration of follow-up of two years, there was no difference in range of motion or clinical and radiographic results between knees that had received a high-flexion posterior cruciate-retaining total knee prosthesis and those that had received a high-flexion posterior cruciate-substituting total knee prosthesis. Level of Evidence: Therapeutic Level I. See Instruction to Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Whether total knee arthroplasty with use of computer-assisted surgical navigation can improve the limb and component alignment is a matter of debate. We hypothesized that total knee arthroplasty with use of computer-assisted surgical navigation is superior to conventional total knee arthroplasty with regard to the precision of implant positioning. Methods: Sequential simultaneous bilateral total knee arthroplasties were carried out in 160 patients (320 knees). One knee was replaced with use of a computer-assisted surgical navigation system, and the other was replaced conventionally without use of computer-assisted surgical navigation. The two methods were compared for accuracy of orientation and alignment of the components as determined by radiographs and computed tomography scans. The mean duration of follow-up was 3.4 years. Results: The mean preoperative Knee Society score was 26 points, with an improvement to 92 points postoperatively, in the computer-assisted total knee arthroplasty group and 25 points, with an improvement to 93 points postoperatively, in the conventional total knee arthroplasty group. Preoperative and postoperative ranges of motion of the knees were similar in both groups. The operating and tourniquet times were significantly longer in the computer-assisted total knee arthroplasty group than in the conventional total knee arthroplasty group (p < 0.001). The groups were not significantly different with regard to the accuracy of component positioning and the number of outliers for the various radiographic parameters (p > 0.05). Conclusions: Our data demonstrate that total knee arthroplasty with use of computer-assisted surgical navigation did not result in more accurate implant positioning than that achieved in conventional total knee arthroplasty, as determined by both radiographs and computed tomography scans. Level of Evidence: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]