A Novel Device for Intraoperative Measurement of Stem Anteversion Angle in Total Hip Arthroplasty
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SUBMITTER: Iwakiri K
PROVIDER: S-EPMC11295631 | biostudies-literature | 2024 Jul
REPOSITORIES: biostudies-literature
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Project description:Combined cup and stem anteversion in THA based on femoral anteversion has been suggested as a method to compensate for abnormal femoral anteversion. We investigated the combined anteversion technique using computer navigation. In 47 THAs, the surgeon first estimated the femoral broach anteversion and validated the position by computer navigation. The broach was then measured with navigation. The navigation screen was blocked while the surgeon estimated the anteversion of the broach. This provided two estimates of stem anteversion. The navigated stem anteversion was validated by postoperative CT scans. All cups were implanted using navigation alone. We determined precision (the reproducibility) and bias (how close the average test number is to the true value) of the stem position. Comparing the surgeon estimate to navigation anteversion, the precision of the surgeon was 16.8 degrees and bias was 0.2 degrees ; comparing the navigation of the stem to postoperative CT anteversion, the precision was 4.8 degrees and bias was 0.2 degrees , meaning navigation is accurate. Combined anteversion by postoperative CT scan was 37.6 degrees +/- 7 degrees (standard deviation) (range, 19 degrees -50 degrees ). The combined anteversion with computer navigation was within the safe zone of 25 degrees to 50 degrees for 45 of 47 (96%) hips. Femoral stem anteversion had a wide variability.Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
| S-EPMC2600986 | biostudies-other
Project description:BackgroundPeriprosthetic hip dislocation after total hip arthroplasty is a devastating postoperative complication. It is often associated with suboptimal orientation of the acetabular component, characterized by the acetabular abduction and anteversion angles obtained from anteroposterior pelvic radiographs. We introduce a novel automated web tool to streamline the subjective and lengthy process of this manual measurement and compare it to manual human measurements.MethodsOne board-certified orthopaedic surgeon used the web tool to make automatic measurements of anteroposterior radiographs of 97 patients who underwent unilateral hip arthroplasty. Manual and web tool measurements included abduction angle and calculated anteversion angle by Liaw's method. Differences between manual and web tool measurements were compared with a paired t-test and Bland-Altman analysis.ResultsThere were no statistically significant differences between the average of manual measurements as compared to the web tool measurement in abduction angle (43.29 ± 7.05 vs 43.00 + 6.22, P = .85), anteversion angle (20.43 ± 7.62 vs 20.82 ± 7.37, P = .52), and ratio of the minor axis of the acetabular cup circumference in the AP radiograph to the total length of the acetabular head (0.42 ± 0.15 vs 0.44 ± 0.15, P = .18). The mean difference of average for abduction angle, anteversion angle, and ratio between the short axis of the transverse ellipse to the total length of the acetabular cup were -0.28, 0.39, and 0.02, respectively. Bland-Altman analysis for all 3 measurements displayed negligible systemic bias with random scattering.ConclusionsAutomated measurements obtained with a novel web tool are in strong agreement with the manually obtained ground truth measurements. The web tool helps to eliminate interobserver differences that arise with manual annotation. The web tool has the potential to streamline acetabular measurements with enhanced accuracy.
| S-EPMC11770501 | biostudies-literature
Project description:BackgroundThere are various traditional landmarks used to estimate the femoral component version, yet none are widely accepted by direct anterior surgeons. The purpose of this study was to compare bony landmarks easily accessible to direct anterior surgeons and to estimate which one provides the best estimate of femoral component anteversion.MethodsA computed tomography database was used to identify 736 left entire-femur computed tomography scans. Seven visible anatomic landmarks were identified using a computer model in which a 45° virtual neck resection was made at 10 mm above the lesser trochanter. Thirteen axes, to reference the femoral stem position, were created between the 7 landmarks. Means and standard deviations (SDs) of angles between each axis and the transepicondylar axis (TEA) were compared for their precision.ResultsThe traditional lesser trochanter predicted anteversion from the TEA was 34.1° (SD 9.7°). Predicted anteversion from the TEA was 3.3° (SD 8.1°) when aligned from the center of the canal to the middle of the medial calcar; 14.0° (SD 8.1°) from the center of the canal to the anterior 1/3 of the medial calcar; and 24.8° (SD 8.5°) from the center of the canal to the most anterior point on the medial calcar.ConclusionsCompared to the lesser trochanter, 7 axes were more precise (lower SD) when predicting the version. Estimating the femoral component position, via simulated data, using 3 points along the medial calcar is a relatively precise and easily accessible tool for surgeons.
| S-EPMC10907387 | biostudies-literature
Project description:IntroductionAccurate measurement of combined component anteversion (CA) is important in evaluating the radiographic outcomes following total hip arthroplasty (THA). The aim of the present study was to evaluate the accuracy and reliability of a novel radiographic method in estimating CA in THA.Materials and methodsThe radiographs and computer tomography of patients who underwent a primary THA were retrospectively reviewed, to measure the radiographic CA (CAr), defined as the angle between a line connecting the center of the femoral head to the most anterior rim of the acetabular cup and a line connecting the center of the femoral head to the base of the femoral head to allow a comparison with the CA measured on the CT (CACT). Subsequently, a computational simulation was performed to evaluate the effect of cup anteversion, inclination, stem anteversion, and leg rotation on the CAr and develop a formula that would correct the CAr according to the acetabular cup inclination based on the best-fit equation.ResultsIn the retrospective analysis of 154 THA, the average CAr_cor, and CACT were 53 ± 11° and 54 ± 11° (p > 0.05), respectively. A strong correlation was found between CAr and CACT (r = 0.96, p < 0.001), with an average bias of - 0.5° between CAr_cor and CACT. In the computational simulation, the CAr was strongly affected by the cup anteversion, inclination, stem anteversion, and leg rotation. The formula to convert the CAr to CA_cor was: CA-cor = 1.3*Car - (17* In (Cup Inclination) - 31.ConclusionThe combined anteversion measurement of THA components on the lateral hip radiograph is accurate and reliable, implying that it could be routinely used postoperatively but also in patients with persistent complaints following a THA.Level of evidenceCross-sectional study, Level III.
| S-EPMC10449991 | biostudies-literature
Project description:ObjectiveTotal hip arthroplasty (THA) involves postoperative risks, such as thigh pain, periprosthetic fractures, and stress yielding. Short, anatomical, metaphyseal-fitting, cementless femoral stems were developed to reduce these postoperative risks. This study aimed to examine the "MiniMAX" prosthesis, which is a new generation, short, anatomical femoral stem made by Medacta.MethodsPatients underwent a low-dose computed tomography scan. Femoral anteversion was measured. We assessed the position and anteversion of the femoral component and compared them with the unoperated side. We also assessed the patients' satisfaction and functional levels at 6 months postsurgery using the Harris Hip Score (HHS) and the Oxford Hip Score (OHS).ResultsNineteen individuals were recruited in this study. We found no significant difference in femoral anteversion between the operated hip and the native hip. Using the HHS and OHS questionnaires, we found clinical improvement in the 6-month postoperative scores compared with the preoperative scores.DiscussionThe new-generation, short, anatomical femoral stem made by Medacta is successful in reproducing natural femoral anteversion, while also improving patients' functioning and lifestyle. Future large-scale, prospective comparison trials are required to further investigate this topic.
| S-EPMC9047853 | biostudies-literature
Project description:BackgroundThe functional safe zone of combined anteversion (CA) shows a superior predictive value for dislocation after total hip arthroplasty (THA) compared to that of the Lewinnek safe zone. Thus, it is necessary to establish a feasible and accurate method for assessing CA for the evaluation of dislocation risk. We aimed to evaluate the reliability and validity of using standing lateral (SL) radiographs for determining CA.MethodsSixty-seven patients who underwent SL radiography and computed tomography (CT) scans after THA were included. Radiographic CA values were obtained via the calculation of the sum of the acetabular cup and femoral stem anteversion (FSA) measurements as obtained from the SL radiographs. Acetabular cup anteversion (AA) was measured based on the tangential line to the face of the cup, whereas FSA was calculated using the developed formula based on the neck-shaft angle. The intra-observer and inter-observer reliabilities for each measurement were examined. Radiological CA values were compared with the CT scan measurements to evaluate their validity.ResultsThe intra-observer and inter-observer agreements of the SL radiography were excellent [intraclass correlation coefficient (ICC) ≥0.90]. The radiographic measurements correlated well with the CT scan measurements (r=0.869, P<0.001). The mean difference between the radiographic and CT scan measurements was -0.55°±4.68° and ranged from 0.3° to 2.2° in terms of the 95% confidence interval (CI).ConclusionsSL radiography is a reliable and valid imaging tool for the assessment of functional CA.
| S-EPMC10061452 | biostudies-literature
Project description:We present a unique case of bladder perforation occurring intraoperatively during primary total hip arthroplasty. It is suspected that the patient's aberrant bladder anatomy, with idiopathic erosion of the quadrilateral space, predisposed the patient to bladder injury. Several preoperative risk factors for bladder injury were identified in the literature. These factors include cemented acetabular components, previous history of hip arthroplasty, history of pelvic trauma or intrapelvic surgery, and poor bone quality. Management of bladder injury, should it occur, includes bladder decompression with a Foley catheter, antibiotic administration, hemodynamic monitoring, and urology consult with close follow-up. This case reinforces the importance of urologic preoperative evaluation for anatomic variations of the bladder. In such cases, intraoperative Foley catheters to prevent distension may reduce the risk of perforation.
| S-EPMC5859462 | biostudies-literature
Project description:Aiming for a combined cup and stem anteversion within a target range is one way to assess appropriate prosthetic component orientation and restoration of functional range of motion. We describe a surgical technique that allows the surgeon to assess the combined anteversion using a handheld accelerometer-based navigation system for total hip arthroplasty through a posterior approach. The femur is prepared first, at which time the femoral version is estimated by the surgeon. The acetabular component is then positioned using the navigation system to estimate anteversion, with the goal of providing a combined version of 37° ± 7°. The described technique allows surgeons to achieve the desired intraoperative combined anteversion.Level of evidenceIV (technical note).
| S-EPMC10514434 | biostudies-literature
Project description:BackgroundAcetabular and femoral component positioning are important considerations in reducing adverse outcomes after total hip arthroplasty (THA). Previous assessments of femoral anteversion examined anatomic femoral anteversion (AFA) referenced to anatomic landmarks. However, this does not provide a functional understanding of the femur's relationship to the hip. We investigate a new measurement, functional femoral anteversion (FFA), and sought to measure its variability across a large sample of patients undergoing THA.MethodsA total of 1008 consecutive patients underwent THA surgery between September 2019 and July 2021. All patients were measured for supine and standing functional femoral rotation (FFR), AFA, and FFA.ResultsThe mean standing FFA was 13.2° ± 12.2° (-27.8° to 52.3°). The mean change in FFR from supine to standing was -2.2° ± 11.8° (-43.0° to 41.9°). Of all, 161 (16%) patients had standing FFA version greater than 25°. Four hundred sixty (46%) patients had standing FFR (internal or external) greater than 10°. One hundred twenty-three (12%) patients exhibited an increase in external rotation from supine to standing of greater than 10°. A moderate, negative linear relationship was observed between AFA and standing external femoral rotation (P <<.001, R = -0.46), indicating people may externally rotate their femur as AFA decreases with age.ConclusionsFunctional alignment of the femur in patients requiring THA is understudied. It is now understood that the femur, like the pelvis, can rotate substantially between functional positions. Enhancing our understanding of FFA and FFR may improve both acetabular and femoral component positioning.
| S-EPMC9576488 | biostudies-literature
Project description:BackgroundIn total hip arthroplasty (THA), component position is critical to avoid instability and improve longevity. Appropriate combined femoral and acetabular component anteversion is important for improved THA stability and increased impingement-free range of motion. In direct anterior THA (DA-THA), concern has been expressed regarding the accuracy of femoral component positioning. This study seeks to quantify acetabular, femoral, and combined component orientation relative to the accepted "safe zones" in patients who have undergone DA-THA.MethodsTwenty-nine patients who had THA performed via direct anterior approach had postoperative computerized tomography scans done to assess femoral anteversion. Stem rotational alignment was measured relative to the transepicondylar axis (TEA) and the posterior condylar axis (PCA) of the femur at the knee. Acetabular abduction and version were recorded on anteroposterior pelvis radiographs.ResultsThe mean stem anteversion was 17.5° (standard deviation = 10.8°) from the TEA and 21.7° (standard deviation = 11.3°) from the PCA. Ten of 30 cups were appropriately anteverted; however, all the cups had appropriate abduction. Combined version when using the TEA resulted in 79% (23/29) of patients within the "safe zone" of 25°-50°. Pearson correlation coefficients were high for both stem anteversion from the TEA (R = 0.96) and PCA (R = 0.98); however, interobserver reliability for combined component anteversion was greater for the TEA (kappa, 0.83 vs 0.65).ConclusionsCombined anteversion within the "safe zone" was achieved 79% of the time with DA-THA. Interestingly, most of the "excessive" combined anteversion appears to be related to increased anteversion of the acetabular component with only 10 patients within the acetabular cup "safe zone" of 5°-25°.
| S-EPMC7451890 | biostudies-literature