Acetabular Placement Accuracy With the Direct Anterior Approach Freehand Technique

Background

Acetabular cup placement in total hip arthroplasty (THA) has been recognized as an important factor in operative success, and accurate cup placement has been the impetus for novel medical technologies.

Comparison of Cemented vs Uncemented Acetabular Component Positioning Using an Imageless Navigation System

Hip navigation was used as an assessment tool to compare ability to reproduce trial and definitive acetabular placement in total hip arthroplasty, using cemented and uncemented components. We demonstrated a significant difference in reproducibility between components. Of 20 uncemented cups, 4 (20%) deviated from the target inclination by 5° or more compared to none of 21 in the cemented group (P = .048). Of the 20 uncemented cups, 7 (35%) deviated from the target version by 5° or more compared to none of 21 in the cemented group (P = .003). This may explain higher rates of revision for dislocation with uncemented components. There was also a significant difference between the groups with regard to deviation from planned leg length (P < .001).     

Revision Total Hip Arthroplasty Using Imageless Navigation With the Concept of Combined Anteversion

Background

The purpose of the study was to evaluate the implant positions and clinical results of revision total hip arthroplasty (THA) using an imageless navigation with the concept of combined anteversion.

Unrecognized Acetabular Component Rotation With Formation of a Pseudoarticulation After Total Hip Arthroplasty

We report an unusual case of an 82-year–old woman who presented with bilateral knee pain and advanced tibial-femoral and patellofemoral arthrosis. A preoperative total lower extremity film revealed an unrecognized, asymptomatic, dislocated right total hip arthroplasty with a rotated acetabular component that likely occurred 12 years earlier. The dislocated prosthetic femoral head appeared to be articulating with a pseudoacetabulum that had formed superiorly and laterally to the acetabular cup. The patient was unaware of any incident where she noticed an acute change after her hip arthroplasty surgery. We believed the patient to have a chronically dislocated hip that was pain free and quite functional for many years, an unusual condition that has not been reported previously in the literature.     

The Use of Patient-Specific Instrumentation Improves the Accuracy of Acetabular Component Placement

Preoperative assessment of acetabular pathology, planning of bone preparation, and implant placement using current imaging, templating, and surgical techniques are imprecise, frequently resulting in component malposition. This study compared the accuracy of 2 surgical approaches: (1) standard preoperative imaging and instrumentation and (2) a novel 3-dimensional computed tomography scan–based preoperative planning software linked to patient- and implant-specific instrumentation (PSI) for placing acetabular components. The PSI group resulted in a significant improvement (P < .05) in the average deviation of implant position (actual vs planned) for version, inclination, and total offset. Fewer clinically relevant screw perforations were observed in the PSI group. This study shows proof of concept and justifies a clinical trial comparing PSI technology with standard surgical techniques.     

Augmented Reality- vs Accelerometer-Based Portable Navigation System to Improve the Accuracy of Acetabular Cup Placement During Total Hip Arthroplasty in the Lateral Decubitus Position

BackgroundThere have been no studies regarding the effectiveness of augmented reality (AR)-based portable navigation systems compared with accelerometer-based portable navigation systems in total hip arthroplasty (THA).MethodsWe retrospectively compared THAs performed using an AR-based portable navigation system (n = 45) and those performed using an accelerometer-based portable navigation system (n = 42). All THAs were performed with the patient in the lateral decubitus position. The primary outcome was the absolute difference between cup placement angles displayed on the navigation screen and those measured on postoperative X-ray.ResultsThe mean absolute differences were significantly smaller in the AR-based portable navigation system group than the accelerometer-based portable navigation system group in radiographic inclination (2.5° ± 1.7° vs 4.6° ± 3.1°; 95% confidence interval 1.1°-3.2°, P < .0001). Similarly, the mean absolute differences were significantly better in the AR-based portable navigation system group in radiographic anteversion (2.1° ± 1.8° vs 6.4° ± 4.2°; 95% confidence interval 3.0°-5.7°, P < .0001). Neither hip dislocation, surgical site infection, nor other complications associated with use of the navigation system occurred in either group.ConclusionThe AR-based portable navigation system may provide more precise acetabular cup placement compared with the accelerometer-based portable navigation system in THA.     

Acetabular Wall Augmentation in Selected Patients With Recurrent Dislocation After THA

We reviewed 42 patients operated with PMMA augmentation of the acetabular wall for recurrent posterior dislocation of cemented total hip arthroplasties with a cemented all-poly acetabular component. 38 patients never experienced subsequent dislocations after the procedure. 4 patients had recurrent dislocations, and two additional patients underwent a revision procedure due to aseptic loosening of the acetabular component. 1, 5 and 10 years survival of the prosthesis free of dislocation were 95%, 95% and 64% respectively. 90% of the patients were satisfied, four patients experienced pain and 3 patients sustained an infection. The procedure is simple, effective, takes less time and results in less blood loss compared to full revision surgery. It should be considered in cases of recurrent posterior dislocation in elderly patients.     

Use of Dual Mobility Acetabular Component and Anterior Approach in Patients With Displaced Femoral Neck Fracture

BackgroundAlthough the antidislocation effect of total hip arthroplasty (THA) via the direct anterior approach (DAA) with dual mobility cup (DMC) for displaced femoral neck fracture (FNF) has already been reported, the clinical result of DMC-DAA-THA for displaced FNF in terms of mortality, complications, and walking ability are still unclear.Methods106 cases with DMC-DAA-THA for displaced FNF were investigated of dislocation; perioperative complications; 3-, 6-, and12-month mortality rate; and pre/early postoperative walking ability. The walking ability was stratified into the following four categories: (1) use of a wheelchair (no walking), (2) walking alongside a support (including walkers designed for the elderly), (3) walking using one stick, and (4) unaided walking.ResultsThere was no dislocation withing one-year postoperative. The 3-, 6-, and 12-month mortality rate was 2.8%, 4.7%, and 5.7%. Total complications occurred in 14 cases (14.7%). Although there was no revision surgery, two cases (1.9%) of intraoperative fracture treated without additional fixation, and one case of postoperative fracture was occurred. Among patients with preinjury walking category 2, 3, and 4 (total 94 cases), the number of patients who recovered same walking category at two-week postoperation was 56 cases (59.6%).ConclusionsOur study demonstrated that DMC-DAA-THA for displaced FNF offered quick recovery of walking ability with no dislocation and low one-year mortality rate. We believe that the combination of early postoperative recovery due to the minimal invasiveness of the DAA and decreased dislocation rate due to increased range of motion by DMC and adequate soft tissue tension by DAA contributed to null dislocation.     

Accuracy of Computer Navigation for Acetabular Component Placement in THA

The accuracy and precision of any computer-aided surgical device is critical to its utility. We asked the following question: how accurate and precise are the values measured by an imageless computer navigation system as compared with those measured using postoperative CT scans? Twenty-five patients (26 hips) underwent primary THA using an imageless computer navigation system for placement of the acetabular component. Inclination and anteversion were measured in the operative coordinate system as defined by Murray. Accuracy, precision, and bias were computed, and Bland-Altman analysis was used to assess levels of agreement. The accuracy (mean ± standard deviation of the absolute difference between computer-assisted navigation and CT) was 1.8° ± 1.2° for inclination and 2.0° ± 2.0° for anteversion. Precision was 3.4° for inclination and 5.5° for anteversion. Bias was 0.52° for inclination and 0.35° for anteversion. Limits of agreement were 4.26° for inclination and 5.58° for anteversion. An imageless computer navigation system can precisely determine acetabular cup position.     

A Pilot Study of Augmented Reality Technology Applied to the Acetabular Cup Placement During Total Hip Arthroplasty

Background

We developed an acetabular cup placement device, the AR-HIP system, using augmented reality (AR). The AR-HIP system allows the surgeon to view an acetabular cup image superimposed in the surgical field through a smartphone. The smartphone also shows the placement angle of the acetabular cup. This preliminary study was performed to assess the accuracy of the AR-HIP system for acetabular cup placement during total hip arthroplasty (THA).

A Comparison of Revision Rates for Dislocation and Aseptic Causes Between Dual Mobility and Large Femoral Head Bearings in Primary Total Hip Arthroplasty With Subanalysis by Acetabular Component Size: An Analysis of 106,163 Primary Total Hip Arthroplasties

BackgroundDual mobility (DM) and large femoral head bearings (≥36 mm) both decrease the risk of dislocation in total hip arthroplasty (THA). There is limited comparable data in primary THA. This study compared the revision rates for dislocation and aseptic causes between DM and large femoral heads and subanalyzed by acetabular component size.MethodsData from the Australian Orthopedic Association National Joint Replacement Registry were analyzed for patients undergoing primary THA for osteoarthritis from January 2008 (the year of first recorded DM use) to December 2019. All DM and large femoral head bearings were identified. The primary outcome measure was the cumulative percent revision (CPR) for dislocation and for all aseptic causes. The results were adjusted by age, sex, and femoral fixation. A subanalysis was performed stratifying acetabular component diameter <58 m and ≥58 mm.ResultsThere were 4942 DM and 101,221 large femoral head bearings recorded. There was no difference in the CPR for dislocation (HR = 0.69 (95% CI 0.42, 1.13), P = .138) or aseptic causes (HR = 0.91 (95% CI 0.70, 1.18), P = .457). When stratified by acetabular component size, DM reduced the CPR for dislocation in acetabular component diameter <58 mm (HR = 0.55 (95% CI 0.30, 1.00), P = .049). There was no difference for diameter ≥58 mm. There was no difference in aseptic revision when stratified by acetabular component diameter.ConclusionThere is no difference in revision rates for dislocation or aseptic causes between DM and large femoral heads in primary THA. When stratified by acetabular component size, DM reduces dislocation for acetabular component diameter <58 mm.Level of EvidenceLevel III.     

Accuracy and Precision of Version Angle Measurements of the Acetabular Component After Total Hip Arthroplasty

The orientation of the acetabular component after total hip arthroplasty is expressed with inclination angle and anteversion angle (VA). We studied the differences in accuracy and precision between VA measured on AP radiographs of the pelvis and those measured on cross-table lateral radiographs when compared to the gold standard measurements on CT using a supine functional pelvic plane as reference. VA was measured for 66 hips at one week after surgery on an AP radiograph of the pelvis (VAP), a cross-table lateral radiograph of the hip (VCL), and CT of the pelvis. Mean (± SD) of error was 2.8° ± 4.1° for VCL, and − 0.57° ± 3.1° for VAP. VAP showed a higher accuracy and precision than VCL. For measurements of VA, we recommend that they be made on an AP radiograph of the pelvis rather than a cross-table lateral radiograph of the hip.     

Augmented Reality for Acetabular Component Placement in Direct Anterior Total Hip Arthroplasty

BackgroundMalposition of the acetabular component of a hip prosthesis can lead to poor outcomes. Traditional placement with fluoroscopic guidance results in a 35% malpositioning rate. We compared the (1) accuracy and precision of component placement, (2) procedure time, (3) radiation dose, and (4) usability of a novel 3-dimensional augmented reality (AR) guidance system vs standard fluoroscopic guidance for acetabular component placement.MethodsWe simulated component placement using a radiopaque foam pelvis. Cone-beam computed tomographic data and optical data from a red-green-blue-depth camera were coregistered to create the AR environment. Eight orthopedic surgery trainees completed component placement using both methods. We measured component position (inclination, anteversion), procedure time, radiation dose, and usability (System Usability Scale score, Surgical Task Load Index value). Alpha = .05.ResultsCompared with fluoroscopic technique, AR technique was significantly more accurate for achieving target inclination (P = .01) and anteversion (P = .02) and more precise for achieving target anteversion (P < .01). AR technique was faster (mean ± standard deviation, 1.8 ± 0.25 vs 3.9 ± 1.6 minute; P < .01), and participants rated it as significantly easier to use according to both scales (P < .05). Radiation dose was not significantly different between techniques (P = .48).ConclusionA novel 3-dimensional AR guidance system produced more accurate inclination and anteversion and more precise anteversion in the placement of the acetabular component of a hip prosthesis. AR guidance was faster and easier to use than standard fluoroscopic guidance and did not involve greater radiation dose.     

Results of Isolated Femoral Component Revision With Well-Fixed Acetabular Implant Retention

The present study was undertaken to evaluate the clinical and radiological results of isolated femoral revisions conducted while retaining well-fixed cementless acetabular sockets. Thirty-nine patients that underwent isolated femoral stem revisions were reviewed. Mean age at time of surgery was 60.5 years, and mean follow-up duration was 4.2 years. Decisions to retain acetabular sockets were based on clinical and radiographic findings and intraoperative stabilities. During revisions, polyethylene liners were exchanged for metal-inlay polyethylene liners to have a metal-on-metal bearing surface in 23 cases. Mean Harris hip score improved from 58 points preoperatively to 85 points at final follow-up (P < .001). With the exception of one patient, no increases in acetabular radiolucent line numbers or thicknesses were observed during follow-up visits. Isolated femoral stem revisions with acetabular socket retention were found to provide excellent clinical and radiographic results.     

Limitations of Imageless Computer-Assisted Navigation for Total Hip Arthroplasty

We prospectively evaluated acetabular cup placement in total hip arthroplasty with an imageless computer navigation system or using conventional manual technique. The achieved cup orientation in the manual group had substantially larger variances and greater placement error than the navigation cases. The use of navigation was abandoned in 3 cases because of excessive pelvic tilt and unreliable registration of the pelvis. Computer navigation system helped improve the accuracy of the acetabular cup placement for total hip arthroplasty in this study. The variation between the intraoperative navigation readings and the computed tomographic values suggests that relying on palpation of bony landmarks through drapes and tissue is a limitation of this method. Further, the variation in pelvic tilt has an effect on cup placement that requires further studies.     

Evaluating Alternate Registration Planes for Imageless,Computer-Assisted Navigation During Total Hip Arthroplasty

BackgroundImageless computer navigation improves component placement accuracy in total hip arthroplasty (THA), but variations in the registration process are known to impact final accuracy measurements. We sought to evaluate the registration accuracy of an imageless navigation device during THA performed in the lateral decubitus position.MethodsA prospective, observational study of 94 patients undergoing a primary THA with imageless navigation assistance was conducted. Patient position was registered using 4 planes of reference: the patient’s coronal plane (standard method), the long axis of the surgical table (longitudinal plane), the lumbosacral spine (lumbosacral plane), and the plane intersecting the greater trochanter and glenoid fossa (hip-shoulder plane). Navigation measurements of cup position for each plane were compared to measurements from postoperative radiographs.ResultsMean inclination from radiographs (41.5° ± 5.6°) did not differ significantly from inclination using the coronal plane (40.9° ± 3.9°, P = .39), the hip-shoulder plane (42.4° ± 4.7°, P = .26), or the longitudinal plane (41.2° ± 4.3°, P = .66). Inclination measured using the lumbosacral plane (45.8° ± 4.3°) differed significantly from radiographic measurements (P < .0001). Anteversion measured from radiographs (mean: 26.1° ± 5.4°) did not differ significantly from the hip-shoulder plane (26.6° ± 5.2°, P = .50). All other planes differed significantly from radiographs: coronal (22.6° ± 6.8°, P = .001), lumbosacral (32.5° ± 6.4°, P < .0001), and longitudinal (23.7° ± 5.2°, P < .0001).ConclusionPatient registration using any plane approximating the long axis of the body provided a frame of reference that accurately measured intraoperative cup position. Registration using a plane approximating the hip-shoulder axis, however, provided the most accurate and consistent measurement of acetabular component position.     

Computed Tomographic Evaluation of Bone Stock in Patients With Crowe Type III Developmental Dysplasia of the Hip: Implications for Guiding Acetabular Component Placement Using the High Hip Center Technique

Background

We evaluated acetabular cup coverage (CC) and rim contact (RC) to evaluate the bone stock above the acetabulum for guiding acetabular component placement using the high hip center technique in patients with Crowe type III developmental dysplasia of the hip.

Overweight and Obese Patients Require Total Hip and Total Knee Arthroplasty at a Younger Age

Osteoarthritis (OA) of the hip and knee is associated with obesity but the exact effect remains unknown. The aim of this study was to investigate the independent association between the age at which total hip (THA) and knee arthroplasty (TKA) are required for end-stage severe OA according to body mass index (BMI) category. A retrospective study of 3,699 patients undergoing primary THR and 4,740 patients undergoing a primary TKA for the treatment of end-stage OA. Patient demographics, BMI, comorbidity, social deprivation, Short form 12 and Western Ontario and McMaster Universities OA Index score pre-operatively were collected. Linear regression analysis identified that there was an earlier age at which THA and TKA were performed with increasing obesity BMI category compared with normal-weight patients when adjusting for confounding variables. Using the normal weight category as the reference group overweight (0.9 years [95% confidence interval, CI] 0.0–1.8) and obese patients in class 1 (3.1 years, 95% CI 2.1–4.2), 2 (5.2 years, 95% CI 3.7–6.7), and 3 (7.4 years, 95% CI 5.0–9.8) required their THA at a significantly (p ≤ 0.04) earlier age. Again, using normal weight category as the reference group overweight (2.1 years, 95% CI 1.3–2.9) and obese patients in class 1 (4.7 years, 95% CI 3.8–5.6), 2 (6.7 years, 95% CI 5.6– 7.7) and 3 (10.5 years, 95% CI 8.9–12.1) required their TKA at a significantly (p < 0.001) earlier age. Overweight and obese patients required their THA and TKA at a significantly younger age. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:348-355, 2020     

Imageless Computer-Assisted versus Conventional Total Hip Arthroplasty: One Surgeon’s Initial Experience

Computer-assisted surgery (CAS) systems are advocated to improve component positioning in THA, though potential operative risks and costs of CAS have fueled debate. The present study examines the radiographic outcomes, operative efficiency, cost, and midterm functional outcomes for patients who underwent THA, either with CAS or conventional instrumentation. Patient baseline characteristics were recorded for 126 lower-extremities in the CAS series, and 215 in the conventional series. There was no difference in Harris Hip Score or leg length discrepancy between series. Inclination angle, blood loss, and operating room times were increased for CAS. These results suggest that CAS confers no advantage over conventional methods regarding accuracy of THA component placement, drives unreimbursed increases in procedure costs, may expose patients to additional operative risk, and produces no functional benefit at midterm follow-up.     

Bariatric Surgery Prior to Total Hip Arthroplasty Is Cost-Effective in Morbidly Obese Patients

BackgroundThe cost-effectiveness of bariatric surgery to achieve weight loss prior to total hip arthroplasty (THA), and decrease the complications and costs associated with THA in the morbidly obese, is unknown. This study evaluated the cost-effectiveness of bariatric surgery prior to THA for morbidly obese patients with end-stage hip osteoarthritis (OA).MethodsA state-transition Markov model was constructed to compare the cost-utility of 2 treatment protocols for patients with morbid obesity and end-stage hip OA: (1) immediate THA and (2) bariatric surgery 2 years prior to THA (combined protocol). The analysis was performed from both a payer and a societal perspective using direct and indirect costs over a 40-year time horizon. Utilities, associated costs, and probabilities for health state transitions were derived from the literature. One-way, 2-way and probabilistic sensitivity analyses were performed to validate the robustness of the base case results, using the standard willingness-to-pay threshold of $100,000/quality-adjusted life years.ResultsFrom the societal perspective, the combined protocol was more effective (13.16 vs 12.26) with less cost ($91,717 vs $92,684) and thus was the dominant strategy over immediate THA. These results were stable across broad ranges for independent model variables. Monte Carlo simulation with 100,000 samples demonstrated that bariatric surgery prior to THA was the preferred cost-effective strategy over 95% of the time from both a societal and payer perspective.ConclusionIn the morbidly obese patient with end-stage hip OA, bariatric surgery prior to THA is a cost-effective strategy for improving quality of life and decreasing societal and payer costs.Level of EvidenceII