Clinical Outcomes after Computed Tomography-Based Total Knee Arthroplasty: A Minimum 3-Year Analyses.

Computed tomography (CT) scan-based three-dimensional (3D) modeling operative technology has been shown to improve upon results of manual total knee arthroplasties (TKAs). Although there are many reports on superior precision of this CT-based technology, there has been continuing interest regarding extended clinical outcomes. The purpose of this study was to compare their clinical outcomes with manual TKAs at approximately 3-year follow-up. Specifically, we analyzed: (1) survivorship, (2) functional outcomes, (3) complications, and (4) radiographic outcomes (i.e., alignment, progressive radiolucencies). A total of 210 patients receiving CT-based TKAs performed by a single surgeon at a single center between July 1, 2016, and February 16, 2018, were compared with 210 manual TKAs completed by the same surgeon immediately preceding implementation of the CT-based technology. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) surveys were collected at ∼3 years postoperatively. Subgroup analyses of pain and physical function scores were performed. Follow-up radiographs were evaluated for alignment, loosening, and/or progressive radiolucencies. There was 100% survivorship at final follow-up. The postoperative mean pain scores for the CT-based cohort and manual cohort were 1 ± 2 (range, 0-14) and 2 ± 3 (range, 0-17), respectively (p < 0.05). The postoperative mean physical function scores for the CT-based cohort and manual cohort were 3 ± 4 (range, 0-18) and 5 ± 5 (range, 0-19), respectively (p < 0.05). The postoperative mean total WOMAC scores for the CT-based cohort and manual cohort were 5 ± 4 (range, 0-32) and 7 ± 8 (range, 0-35), respectively (p < 0.05). There were low numbers of postoperative complications at final follow-up in either cohort. None exhibited progressive radiolucencies by final follow-up. The 3-year postoperative clinical outcomes support excellent survivorship and radiographic outcomes, low complication rates, as well as improved pain, physical function, and total WOMAC scores for CT-based TKAs. Therefore, patients who undergo CT-based 3D modeling TKAs should expect to have superior long-term clinical outcomes.

Results of Robotic-Assisted Versus Manual Total Knee Arthroplasty at 2-Year Follow-up.

Robotic-assisted technology has been developed to optimize the consistency and accuracy of bony cuts, implant placements, and knee alignments for total knee arthroplasty (TKA). With recently developed designs, there is a need for the reporting longer than initial patient outcomes. Therefore, the purpose of this study was to compare manual and robotic-assisted TKA at 2-year minimum for: (1) aseptic survivorship; (2) reduced Western Ontario and McMaster Universities Osteoarthritis Index (r-WOMAC) pain, physical function, and total scores; (3) surgical and medical complications; and (4) radiographic assessments for progressive radiolucencies. We compared 80 consecutive cementless robotic-assisted to 80 consecutive cementless manual TKAs. Patient preoperative r-WOMAC and demographics (e.g., age, sex, and body mass index) were not found to be statistically different. Surgical data and medical records were reviewed for aseptic survivorship, medical, and surgical complications. Patients were administered an r-WOMAC survey preoperatively and at 2-year postoperatively. Mean r-WOMAC pain, physical function, and total scores were tabulated and compared using Student's t-tests. Radiographs were reviewed serially throughout patient's postoperative follow-up. A p < 0.05 was considered significant. The aseptic failure rates were 1.25 and 5.0% for the robotic-assisted and manual cohorts, respectively. Patients in the robotic-assisted cohort had significantly improved 2-year postoperative r-WOMAC mean pain (1 ± 2 vs. 2 ± 3 points, p = 0.02), mean physical function (2 ± 3 vs. 4 ± 5 points, p = 0.009), and mean total scores (4 ± 5 vs, 6 ± 7 points, p = 0.009) compared with the manual TKA. Surgical and medical complications were similar in the two cohorts. Only one patient in the manual cohort had progressive radiolucencies on radiographic assessment. Robotic-assisted TKA patients demonstrated improved 2-year postoperative outcomes when compared with manual patients. Further studies could include multiple surgeons and centers to increase the generalizability of these results. The results of this study indicate that patients who undergo robotic-assisted TKA may have improved 2-year postoperative outcomes.

The Association of Patient and Procedural Factors on Improved Outcomes: A Cluster Analysis on 853 Total Knee Arthroplasty Patients.

Many studies involving robotic-assisted total knee arthroplasty (RATKA) have demonstrated superiority regarding soft tissue balance and consistency with alignment target achievement. However, studies investigating whether RATKA is associated with improved patient outcomes regarding physical function and pain are also important. Therefore, we performed a cluster analysis and examined factors that contributed to differences in patient-reported outcome measures (PROMs). Specifically, we analyzed: (1) reduced WOMAC (rWOMAC) scores regarding pain and function; (2) usage of RATKA; (3) common patient comorbidities; as well as (4) patient demographic factors. The rWOMAC score is an abbreviated PROM that includes pain and physical function domains. This study analyzed 853 patients (95 conventional and 758 robotic-assisted) who had completed preoperative, 6-month, and 1-year postoperative rWOMAC surveys. Two clusters were constructed using rWOMAC pain and function scores at 1 year. Cluster 1 included 753 patients who had better outcomes at 1 year (mean rWOMAC pain = 0.9, mean rWOMAC function = 1.4), and cluster 2 included 100 patients who had worse outcomes at 1 year (mean rWOMAC pain = 7.7, mean rWOMAC function = 10.4). The clusters were compared to determine (1) how scores improved and (2) what patient characteristics were significantly different between clusters. Cluster 1 demonstrated greater improvement from preoperative to 6 months or 1 year (p = 0.0013 for pain preoperative to 6 months, p< 0.0001 for other measures) and 6 months to 1 year (p< 0.0001). Comparisons demonstrated that cluster 1 had older patients (67 vs. 65 years, p = 0.0479) who had lower body mass index or BMIs (31.8 vs. 33.9 kg/m2, p = 0.0042) and no significant differences in sex (p = 0.7849). Cluster 1 also had a significantly higher percentage of RATKA patients (90 vs. 79%, p< 0.001). Cluster analyses provided differentiating factors which were associated with improved postoperative rWOMAC pain and function scores at 1 year. Patients undergoing robotic-assisted TKA were associated with better rWOMAC pain and function scores from preoperative to 6 months and 1 year.

Total Knee Arthroplasty in the Valgus Knee: Can New Operative Technologies Affect Surgical Technique and Outcomes?

INTRODUCTION: Valgus knee deformities can sometimes be challenging to address during total knee arthroplasties (TKAs). While appropriate surgical technique is often debated, the role of new operative technologies in addressing these complex cases has not been clearly established. The purpose of this study was to analyze the usefulness of computed tomography scan (CT)-based three-dimensional (3D) modeling operative technology in assisting with TKA planning, execution of bone cuts, and alignment. Specifically, we evaluated valgus TKAs performed using this CT-based technology for: (1) intraoperative implant plan, number of releases, and surgeon prediction of component size; (2) survivorship and clinical outcomes at a minimum follow up of one year; and (3) radiographic outcomes. MATERIALS AND METHODS: A total of 152 patients who had valgus deformities receiving a CT-based TKA performed by a single surgeon were analyzed. Cases were performed using an enhanced preoperative planning and real-time intraoperative feedback and cutting tool. The surgeon predicted and recorded implant sizes preoperatively and all patients received implants with initial and final implant alignment, flexion/extension gaps, and full or partial soft tissue releases recorded. A modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR.) scores were collected preoperatively and at approximately six months and one year postoperatively. Preoperative coronal alignment ranged from 1 to 13° valgus. Follow-up radiographs were also evaluated for alignments, loosenings, and/or progressive radiolucencies. RESULTS: A total of 96% of cases were corrected to within 3° of mechanical neutral. For outlier cases, initial deformities ranged from valgus 5 to 13°, with final alignment ranging from 4 to 8° valgus (mean 4° correction). Patients had mean femoral internal rotation of 2° and mean femoral flexion of 4°. The surgeon was within one size on the femur and tibia 94 and 100% of the time, respectively. Only one patient required a lateral soft tissue release and one patient had osteophytes removed, which required a medial soft tissue release. Five patients required manipulations under anesthesia. Aside from these, there were no postoperative medical and/or surgical complications and there was 100% survivorship at final follow up. WOMAC and KOOS, JR. scores improved significantly from a mean of 21 ± 9 and 48 ± 10 points preoperatively to 4 ± 6 (p<0.05) and 82 ± 15 (p<0.05) at final follow up, respectively. None of the cases exhibited progressive radiolucencies by final follow up. DISCUSSION: A limitation of this study was not evaluating dynamic kinematics in these patients to determine if rotation had any effects on kinematics. Future studies will evaluate this concern. Nevertheless, the technology successfully assisted with planning, executing bone cuts, and achieving alignment in TKAs complicated by the deformity. This may allow surgeons to predictably avoid soft tissue releases and accurately know component sizes preoperatively, while consistently achieving desired postoperative alignment. CONCLUSIONS: This study demonstrated the utility of CT-based 3D modeling techniques for challenging valgus deformity cases. Use of 3D modeling allowed the TKA components to be positioned according to the patient's anatomy in the coronal, transverse, and sagittal planes. When making these intraoperative implant adjustments, the surgeon may choose to place components outside the preoperative planning guidelines based on the clinical needs of the patient.

Surgical Tray Optimization and Efficiency: The Impact of a Novel Sealed Sterile Container and Instrument Tray Technology.

INTRODUCTION: As bundle payments have begun focusing on orthopaedic procedures, particularly total knee arthroplasties (TKAs), surgeons and hospitals have evaluated methods for improving efficiency. Few studies have investigated the impact of novel, sealed-container and instrument-tray technology on turnover and costs. Therefore, the purpose of this study was to compare traditional and sealed container-sterilized TKA surgical trays by: 1) investigating the setup and clean-down time in the operating room (OR); 2) examining trays processing time in central sterile supply (CS); and 3) estimating OR and CS costs and waste produced. MATERIALS AND METHODS: An interdisciplinary team determined points throughout a TKA tray single-case life cycle that could cause variations in turnover time. The times were recorded for two different TKA tray configurations. Process A utilized instruments housed in vendor trays that were "blue" wrap sterilized, while Process B employed optimized trays that were sealed container-sterilized. Times were recorded during preoperative setup and postoperative clean down in the OR and CS. Reductions in mean OR or CS times were used to estimate cost savings. Wastes were analyzed for each method. Statistical analyses using Student t-tests were used to determine statistical differences and a p-value of less than 0.05 was considered significant. RESULTS: Overall, the use of optimized trays and sealed sterilization containers reduced the turnover time by 57 minutes and the number of trays by a mean of three. OR and CS processing yearly savings were estimated to be $249,245. Waste disposal was an estimated 10,590 ounces and 450 ounces for traditional and sealed containers, respectively. CONCLUSION: Novel sealed sterilization containers demonstrated increased efficiency in the total turnover time of TKA trays. This is important for surgeons participating in bundle payments who perform surgery in a hospital and ambulatory surgery center. Reduced turnover time could potentially increase case load and decrease the need for extra instrumentation or loaner trays. This simple means of increasing efficiency could be used as a model for surgeons wishing to streamline surgical trays and reduce costs.