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.     

Revision Total Hip Arthroplasty: The Acetabular Component

Intermediate and long-term results of revision total hip arthroplasty performed with the use of a cemented acetabular component have been disappointing, with high rates of radiographic and clinical failure. Other methods of acetabular revision involving the use of threaded cups and bipolar implants have also met with high failure rates. Although the long-term results of revision arthroplasty with uncemented acetabular components, especially in terms of polyethylene wear and pelvic osteolysis, are not yet available, the intermediate results have been excellent.     

The Functional Mechanics of the Acetabular Component in Total Hip Arthroplasty

BackgroundTotal hip arthroplasty functional safe zones match postural hip changes to dynamic positioning of the acetabular component. We studied integrating the Anteinclination (AI) cup angle into the spinopelvic environment, defining normative values for all parameters and calculating adjustments to AI for each degree of altered standing pelvic position and postural mobility from these values. A sagittal geometric model was employed to determine these values using established spinopelvic parameter angles.MethodsTheoretical normative Pelvic Incidence (PI) specific values were calculated using a triangular construct employing a linear equation describing the functional relationship between the pelvic parameters at a mobility producing an isosceles solution for normative acetabular angles. Individual optimal AI cup values for altered Sacral Slope (SS)/pelvic tilt (sPT) and mobility (dSS) were calculated using specific ratios of angular change between parameters correcting from these normative values.ResultsA PI:SS:sPT ratio of angular change of 3:2:1 at dSS = 25° mobility creates an isosceles condition solving for PI specific theoretical normative values for all construct parameters. Individualized tilt correction applies to each posture a +0.25° AI alteration for each +1° sPT increase from this architectural value. Mobility correction applies a +0.5° standing AI and ?0.5° sitting AI alteration for each ?1° dSS < 25°, the opposite for each +1° dSS > 25°. The Sacroacetabular angle/Pelvic acetabular angle (SAA/PAA) index describes the underlying spinopelvic environment the cup functions within.ConclusionThis model quantitatively integrates an implanted acetabular component into the host spinopelvic environment. Theoretical normative and individual optimal cup orientations are passively determined by these conditions of standing pelvic position and mobility.     

人工全髋关节置换术治疗髋臼发育不良近期疗效观察

目的：探讨在髋臼发育不良的病例行人工全髋关节置换术时人工髋臼安放的方法。方法：对15例22个因髋臼发育不良导致骨关节炎的病例，在行人工全髋关节置换术时，根据髋臼发育不良的程度，采用了髋臼外上缘植骨，加深髋臼及髋臼轻度内陷等三种方法。术后3、6、9、12个月及以后每半年以同等条件投照双侧髋关节正位X线片，观察人工髋臼安放的角度及人工髋臼与髋臼骨床愈合的情况。平均随访24个月。结果：随访时发现加深髋臼及髋臼轻度内陷的病例，人工髋臼与髋臼骨床接触良好，角度满意，关节功能恢复优良。而髋臼外上缘植骨的病例，术后2年时植骨块与人工髋臼之间出现了透亮带。结论：髋臼发育不良导致髋关节骨关节炎的病例在施行人工关节置换术时应根据髋臼骨床的情况采用不同的手术方式安放人工髋臼。特别是在髋臼较浅，而髋臼骨床底部骨质较多的情况下，应采用向内切磨髋臼：加深髋臼后安放人工髋臼。本组病例大部分采取此方法，收到了十分满意的临床效果。但手术中应注意不宜切磨髋臼过深，影响到髋臼内壁的稳定。     

Primary Total Hip Arthroplasty With a Spongy Metal Surface Acetabular Component for Hip Dysplasia

We evaluated the clinical and radiographic results of primary total hip arthroplasty for 81 dysplastic hips (71 patients) using cementless Spongiosa Metal II cups (ESKA Implants, Lübeck, Germany). The mean follow-up period was 6.4 years (minimum 5 years), and the preoperative mean Japanese Orthopaedic Association hip score had improved from 45.2 to 87.4 points at the latest follow-up. The radiographic outcome was no aseptic loosening in all 81 hips. The hip center was located significantly more superior than in the contralateral normal hip in 45 patients, but the difference was less than 10 mm; however, there was no significant difference in the lateral position of the hip center. The use of a Spongiosa Metal II cup for dysplastic hips provided satisfactory 5- to 10-year clinical and radiographic results.     

Accurate Acetabular Component Orientation After Total Hip Arthroplasty Using an Acetabular Alignment Guide

Between February 2005 and August 2006, we recorded acetabular component orientation in 90 patients (100 hips) who underwent primary total hip arthroplasty (THA), to determine whether using an alignment guide ensures accurate acetabular positioning. In the alignment-guide group (46 patients; 48 hips), a guide was placed on the pelvis, a Kirschner wire (K-wire) was attached to the guide, and orientation of the acetabular component was confirmed by both the surgeon and an assistant. In the control group (44 patients; 52 hips), a K-wire was not used and the angle was confirmed by the surgeon alone. Radiographic acetabular component inclination and anteversion and computed tomography anteversion were determined. There was no significant difference in mean component orientation between the 2 groups. However, the SD was significantly smaller in the alignment-guide group, showing that consistent acetabular component orientation in primary THA is highly reproducible when an acetabular alignment guide with an attached K-wire is used.     

Effect of Acetabular Component Positioning on Functional Outcomes in Primary Total Hip Arthroplasty

Background

Acetabular component positioning is crucial to a successful total hip arthroplasty (THA). This study evaluated the effect of absolute acetabular component position as well as acetabular position relative to bony anatomy on patient-reported functional outcomes after primary THA.

髋臼缺损时的全髋置换

目的研究髋臼骨缺损时全髋置换术髋臼重建的手术方法.方法因先天性髋关节发育不良、全髋关节置换术失败等原因致髋臼缺损的178例(215髋)行全髋置换术或翻修术,应用非骨水泥假体臼,采用加深髋臼、上移髋臼、大型髋臼填充或结构植骨等方法重建骨性髋臼,其中男62例、女116例,178例中162例随访12个月～10年,平均62个月.结果根据MerleD'Aubigne评分方法,优40例,良69例,中50例,差3例.结论各种髋臼骨缺损应根据X线拍片及CT加以明确,观察其运动中心、上移程度,对髋臼重建方法的选择特别有意义.非骨水泥假体重建成功与否有赖于假体稳定并尽量多与宿主骨接触并避免或减少结构性植骨.     

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.     

Midterm Survivorship After Revision Total Hip Arthroplasty With a Custom Triflange Acetabular Component

Background

Custom triflange acetabular components are being increasingly used for the reconstruction of Paprosky type IIIB acetabular defects. However, midterm survivorship data are lacking.

Effect of Cementless Acetabular Component Orientation,Position, and Containment in Total Hip Arthroplasty for Congenital Hip Disease

We evaluated the effect of the inclination angle, position, and containment of 53 cementless cups inserted in patients with congenital hip disease (CHD), after a minimum of 10 years of follow-up. The polyethylene wear rate was significantly greater when the cup was placed in more than 45° inclination (P = .045) or if the cup was placed lateral to the teardrop position by more than 25 mm (P = .001). Aseptic loosening of the femoral component was significantly greater when the cup was placed more than 25 mm superiorly to the teardrop (P = .049). Cup placement of more than 25 mm lateral to the teardrop affected significantly periacetabular osteolysis (P = .032). In CHD cases, it is preferable to avoid excessive vertical inclination, lateral, and superior placement of cementless cups in an attempt to obtain better containment.     

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.