Validation of a Novel Method of Measuring Cup Orientation Using BiPlanar Simultaneous Radiographic Images.

BACKGROUND: Accurate acetabular component positioning is paramount to the success of total hip arthroplasty (THA). Two-dimensional imaging alone remains a popular tool for implant position assessment despite known limitations. We investigated the accuracy of a novel method for assessing acetabular component position based upon orthogonal simultaneous biplanar X-ray images. METHODS: There were forty consecutive patients who had a preexisting THA on the contralateral side who underwent both computed tomography (CT) and simultaneous orthogonal biplanar radiographic scans for preoperative planning of THA. The operative inclination (OI) and operative anteversion (OA) of the acetabular cup were calculated by a new measurement method using the biplanar simultaneous scans. Those measurements were compared to measurement of the cup orientation on CT. The measurements were made by 2 independent observers. Interobserver correlation coefficients were calculated between the 2 observers to measure reliability. RESULTS: The mean error in OA measurement of the acetabular cup between simultaneous orthogonal biplanar radiographic and CT imaging was 0.5° (SD: 1.9°, minimum -4.0°, maximum 5.0°), the mean error in OI was 0.0° (SD: 1.7°, minimum -5.0°, maximum 4.0°). The average absolute error was 1.5° for OA and 1.2° for OI. Interobserver correlation coefficient was 0.83 for OA and 0.93 for OI. CONCLUSION: The novel method of measuring cup orientation using simultaneous biplanar radiographic scans utilized in this study was accurate and reproducible between observers compared to CT measurements.

Total Knee Arthroplasty Hospital Costs by Time-Driven Activity-Based Costing: Robotic vs Conventional.

BACKGROUND: Total knee arthroplasty (TKA) represents a major national health expenditure. The last decade has seen a surge in robotic-assisted TKA (roTKA); however, literature on the costs of roTKA as compared to conventional TKA (cTKA) is limited. The purpose of this study was to assess the costs associated with roTKA as compared to cTKA. METHODS: This was a retrospective cohort cost-analysis study of patients undergoing primary, elective roTKA or cTKA from July 2020 to March 2021. Time-driven activity-based costing (TDABC) was used to determine granular costs. Patient demographics, medical/surgical details, and costs were compared. RESULTS: A total of 2058 TKAs were analyzed (1795 cTKAs and 263 roTKAs). roTKA patients were more often male (50.2% vs 42.3%; P = .016), and discharged home (98.5% vs 93.7%; P = .017), and had longer operating room (OR) time (144.6 vs 130.9 minutes; P < .0001), and lower length of stay (LOS) (1.8 vs 2.1 days; P < .0001). roTKA costs were 2.17× greater for supplies excluding implant (P < .0001), 1.18× for total supplies (P < .0001), 1.12× for OR personnel (P < .0001), and 1.05× for total personnel (P = .0001). Implant costs were similar (P = .076), but 0.98× cheaper for post-anesthesia care unit personnel (P = .018) and 0.84× for inpatient personnel (P < .0001). Overall hospital costs for roTKA were 1.10× more than cTKA (P < .0001). CONCLUSION: roTKA had higher total hospital costs than cTKA. Despite a lower LOS, the longer OR time with higher supply and personnel costs resulted in a costlier procedure. Understanding the costs of roTKA is essential when considering the value (ie, outcomes per dollars spent) of this modern technology.

Analysis of Preoperative Screening Criteria for Total Joint Arthroplasty in a Veteran Population.

BACKGROUND: This study describes the experience of patients who initially failed total joint arthroplasty preoperative screening criteria but were subsequently optimized and underwent surgery. METHODS: Time to optimization from the patients' initial clinic visit was recorded. Following surgery, patients' body mass index and lab work were tracked to determine whether they "relapsed" to their preoptimized state. Descriptive statistics determined (1) the length of time to meet screening criteria and (2) which screening criteria took the longest to optimize. RESULTS: Only 11 of 84 patients (13%) required greater than 1 year to meet criteria. Most patients (76%) "relapsed" to their previous nonqualifying status after surgery; however, this reversion did not contribute significantly to an increased rate of complication in short-term follow-up (P = .4298). CONCLUSION: Patients in this study were able to achieve preoperative screening criteria for total joint arthroplasty in less than 1 year. Relapsing after surgery does not appear to adversely affect clinical outcomes.