Aims. Cross-table lateral (CTL) radiographs are commonly used to measure
Introduction. Cross table lateral (CTL) radiographs are commonly used to measure
Introduction:. The lateral radiographs are useful in evaluation of the
Several radiological methods of measuring anteversion of the acetabular component after total hip arthroplasty (THA) have been described. These are limited by low reproducibility, are less accurate than CT 3D reconstruction, and are cumbersome to use. These methods also partly rely on the identification of obscured radiological borders of the component. We propose two novel methods, the Area and Orthogonal methods, which have been designed to maximize use of readily identifiable points while maintaining the same trigonometric principles. A retrospective study of plain radiographs was conducted on 160 hips of 141 patients who had undergone primary THA. We compared the reliability and accuracy of the Area and Orthogonal methods with two of the current leading methods: those of Widmer and Lewinnek, respectively.Aims
Patients and Methods
The interaction between the lumbosacral spine
and the pelvis is dynamically related to positional change, and
may be complicated by co-existing pathology. This review summarises
the current literature examining the effect of sagittal spinal deformity
on pelvic and acetabular orientation during total hip arthroplasty
(THA) and provides recommendations to aid in placement of the acetabular
component for patients with co-existing spinal pathology or long
spinal fusions. Pre-operatively, patients can be divided into four
categories based on the flexibility and sagittal balance of the
spine. Using this information as a guide, placement of the acetabular
component can be optimal based on the type and significance of co-existing
spinal deformity. Cite this article:
We assessed the orientation of the acetabular
component in 1070 primary total hip arthroplasties with hard-on-soft, small
diameter bearings, aiming to determine the size and site of the
target zone that optimises outcome. Outcome measures included complications,
dislocations, revisions and ΔOHS (the difference between the Oxford
Hip Scores pre-operatively and five years post-operatively). A wide
scatter of orientation was observed (2 This study demonstrated that with traditional technology surgeons
can only reliably achieve a target zone of ±15°. As the optimal
zone to diminish the risk of dislocation is also ±15°, surgeons
should be able to achieve this. This is the first study to demonstrate
that optimal orientation of the acetabular component improves the
functional outcome. However, the target zone is small (± 5°) and
cannot, with current technology, be consistently achieved. Cite this article:
Aims. Pelvic incidence (PI) is considered an important anatomical parameter for determining the sagittal balance of the spine. The contribution of an abnormal PI to hip osteoarthritis (OA) remains controversial. In this study, we aimed to investigate the relationship between PI and hip OA, and the difference in PI between hip OA without anatomical abnormalities (primary OA) and hip OA with developmental dysplasia of the hip (DDH-OA). Methods. In this study, 100 patients each of primary OA, DDH-OA, and control subjects with no history of hip disease were included. CT images were used to measure PI, sagittal femoral head coverage, α angle, and
Aims. The effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, different in patients with AR compared to a control group?; and is there a correlation between iliac rotation and acetabular version?. Methods. A retrospective, review board-approved, controlled study was performed including 120 hips in 86 consecutive patients with symptomatic FAI or hip dysplasia. Pelvic CT scans were reviewed to calculate parameters for sagittal balance (pelvic incidence (PI), PT, and sacral slope), anterior pelvic plane angle, pelvic inclination, and external rotation of the iliac wing and were compared to a control group (48 hips). The 120 hips were allocated to the following groups: AR (41 hips), hip dysplasia (47 hips) and cam FAI with normal acetabular morphology (32 hips). Subgroups of total AR (15 hips) and high
Reorientating pelvic osteotomies are performed to improve femoral head coverage and secondary degenerative arthritis. A rectangular triple pelvic innominate osteotomy (3PIO) is performed in symptomatic cases. However, deciding optimal screw fixation type to avoid complications is questionable. Therefore, this study aimed to investigate the biomechanical behavior of two different acetabular screw configurations used for rectangular 3PIO osteosynthesis. It was hypothesized that bi-directional screw fixation would be biomechanically superior to mono-axial screw fixation technique. A rectangular 3PIO was performed in twelve right-side artificial Hemi-pelvises. Group 1 (G1) had two axial and one transversal screw in a bi-directional orientation. Group 2 (G2) had three screws in the axial direction through the iliac crest. Acetabular fragment was reoriented to 10.5° inclination in coronal plane, and 10.0° increased anteversion along axial plane. Specimens were biomechanically tested until failure under progressively increasing cyclic loading at 2Hz, starting at 50N peak compression, increasing 0.05N/cycle. Stiffness was calculated from machine data.
Total hip arthroplasty (THA) is one of the most successful surgical procedures of modern times, however debate continues as to the optimal orientation of the acetabular component and how to reliably achieve this. We hypothesised that functional CT-based planning with patient specific instruments using the Corin Optimised Positioning System (OPS) would provide more accurate component alignment than the conventional freehand technique using 2D templating. A pragmatic single-centre, patient-assessor blinded, randomised control trial of patients undergoing THA was performed. 54 patients (age 18–70) were recruited to either OPS THA or conventional THA. All patients received a cementless acetabular component. Patients in both arms underwent pre- and post-operative CT scans, and four functional x-rays (standing and seated). Patients in the OPS group had a 3D surgical plan and bespoke guides made. Patients in the conventional group had a surgical plan based on 2D templating x-rays, and the pre-operative target acetabular orientation was recorded by the surgeon. The primary outcome measure was the difference between planned and achieved
INTRODUCTION. Component impingement in total hip arthroplasty (THA) can cause implant damage or dislocation. Dual mobility (DM) implants are thought to reduce dislocation risk, but impingement on metal acetabular bearings may cause femoral component notching. We studied the prevalence of (and risk factors for) femoral notching with DM across two institutions. METHODS. We identified 37 patients with minimum 1-year radiographic follow-up after primary (19), revision (16), or conversion (2) THA with 3 distinct DM devices between 2012 and 2017. Indications for DM included osteonecrosis, femoral neck fracture, concomitant spinal or neurologic pathology, revision or conversion surgery, and history of prosthetic hip dislocation. Most recent radiographs were reviewed and assessed for notching.
Purpose. Spinopelvic parameters are associated with the development of symptomatic femoroacetabular impingement and subsequent osteoarthritis. Pelvic incidence (PI) characterizes the sagittal profile of the pelvis and is important in the regulation of both lumbar lordosis and pelvic orientation (i.e. tilt). The purpose of this imaging-based study was to test the association between PI and acetabular morphology. Methods. Measurements of the pelvis and acetabulum were performed for 96 control patients and 29 hip dysplasia patients using 3D-computed topography (3D-CT) scans. Using previously validated measurements the articular cartilage and cotyloid fossa area of the acetabulum, functional acetabular version/inclination, acetabular depth, pelvic tilt, sacral slope, and PI were calculated. Non-parametric statistical tests were used; significance was set at p<0.05. Results. Of the 125 scans analyzed in this study, 65% were females and the average age was 24.8±6.0 years old. Thirty-six (14.4%) hips had acetabular retroversion; 178 (71.2%) had normal acetabular version; and 36 (14.4%) had high
We studied 33 third generation, alumina ceramic-on-ceramic bearings retrieved from cementless total hip replacements after more than six months in situ. Wear volume was measured with a Roundtest machine, and acetabular orientation from the anteroposterior pelvic radiograph. The overall median early wear rate was 0.1 mm. 3. /yr for the femoral heads, and 0.04 mm. 3. /yr for the acetabular liners. We then excluded hips where the components had migrated. In this stable subgroup of 22 bearings, those with an
Introduction. Pelvic flexion and extension in different body positions can affect acetabular orientation after total hip arthroplasty, and this may predispose patients to dislocation. The purpose of this study was to evaluate functional acetabular component position in total hip replacement patients during standing and sitting. We hypothesize that patients with degenerative lumbar disease will have less pelvic extension from standing to sitting, compared to patients with a normal lumbar spine or single level spine disease. Methods. A prospective cohort of 20 patients with primary unilateral THR underwent spine-to-ankle standing and sitting lateral radiographs that included the lumbar spine and pelvis using EOS imaging. Patients were an average age of 58 ± 12 years and 6 patients were female. Patients had (1) normal lumbar spines or single level degeneration, (2) multilevel degenerative disc disease or (3) scoliosis. We measured
Introduction. Implant position plays a major role in the mechanical stability of a total hip replacement. The standard modality for assessing hip component position postoperatively is a 2D anteroposterior radiograph, due to low radiation dose and low cost. Recently, the EOS® X-Ray Imaging Acquisition System has been developed as a new low-dose radiation system for measuring hip component position. EOS imaging can calculate 3D patient information from simultaneous frontal and lateral 2D radiographs of a standing patient without stitching or vertical distortion, and has been shown to be more reliable than conventional radiographs for measuring hip angles[1]. The purpose of this prospective study was to compare EOS imaging to computer tomography (CT) scans, which are the gold standard, to assess the reproducibility of hip angles. Materials and Methods. Twenty patients undergoing unilateral THA consented to this IRB-approved analysis of post-operative THA cup alignment. Standing EOS imaging and supine CT scans were taken of the same patients 6 weeks post-operatively. Postoperative cup alignment and femoral anteversion were measured from EOS radiographs using sterEOS® software. CT images of the pelvis and femur were segmented using MIMICS software (Materialise, Leuven, Belgium), and component position was measured using Geomagic Studio (Morrisville, NC, USA) and PTC Creo Parametric (Needham, MA). The Anterior Pelvic Plane (APP), which is defined by the two anterior superior iliac spines and the pubic symphysis, was used as an anatomic reference for acetabular inclination and anteversion. The most posterior part of the femoral condyles was used as an anatomic reference for femoral anteversion. Two blinded observers measured hip angles using sterEOS® software. Reproducibility was analysed by the Bland-Altman method, and interobserver reliability was calculated using the Cronbach's alpha (∝) coefficient of reliability. Results. The Bland-Altman analysis of test-retest reliability indicated that the 95% limits of agreement between the EOS and CT measurements ranged from −3° to 4° for acetabular inclination, from −5° to 5° for
Introduction. This study aims to determine how the acetabular version changes during the key developmental stage of adolescence, and what contributes to this change. In addition, we examined whether patient factors (BMI, activity levels) or the femoral-sided anatomy contribute to any observed changes. Patients/Materials & Methods. This prospective longitudinal cohort study included 19 volunteers (38 healthy hips). The participants underwent clinical examination (BMI, range of movement assessment), MRIs of both hips at recruitment and at follow-up (6 ± 2 years) and HSS Paediatric Functional Activity Brief Scale (Pedi-FABS) questionnaire. MRI scans were assessed at both time points to determine change of the tri-radiate cartilage complex (TCC), the
Purpose of the study: Two principle angles describe the orientation of the acetabular reconstruction of hip arthroplsty: lateral inclination and anteversion. Lateal inclination is easily determined on the plain x-ray but the measurement of anteversion generally requires axial computed tomography (CT). The values measured for
Background. Supine positioning during direct anterior approach total hip arthroplasty (DAA THA) facilitates use of fluoroscopy, which has been shown to improve acetabular component positioning on plane radiograph. This study aims to compare 2- dimensional intraoperative radiographic measurements of acetabular component position with RadLink to postoperative 3- dimensional SterEOS measurements. Methods. Intraoperative fluoroscopy and RadLink (El Segundo, CA) were used to measure acetabular cup position intraoperatively in 48 patients undergoing DAA THA. Cup position was measured on 6-week postoperative standing EOS images using 3D SterEOS software and compared to RadLink findings using Student's t-test. Safe-zone outliers were identified. We evaluated for measurement difference of > +/− 5 degrees. Results. RadLink acetabular cup abduction measurement (mean 43.0°) was not significantly different than 3D SterEOS in the anatomic plane (mean 42.6°, p = 0.50) or in the functional plane (mean 42.7°, p = 0.61) (Fig. 1–2). RadLink
The problem associated with ceramic on ceramic total hip replacement (THR) is audible noise. Squeaking is the most frequently documented sound. The incidence of squeaking has been reported to wide range from 0.7 to 20.9%. Nevertheless there is no study to investigate on incidence of noise in computer assisted THR with ceramic on ceramic bearing. The purpose of this study was to determine the incidence and risks factors associated with noise. We retrospectively reviewed 200 patients (202 hips) whom performed computer assisted THR (Orthopilot, B. Braun, Tuttlingen, Germany) with ceramic on ceramic bearing between March 2009 and August 2012. All procedures underwent uncemented THR with posterior approach by single surgeon. All hips implanted with PLASMACUP and EXIA femoral stem (B. Braun, Tuttlingen, Germany). All cases used BIOLOX DELTA (Ceramtec, AG, Plochingen, Germany) ceramic liner and head. The incidence and type of noise were interviewed by telephone using set of questionnaire. Patient's age, weight, height, body mass index, acetabular cup size, femoral offset size determined from medical record for comparing between silent hips and noisy hips. The acetabular inclination angle,
Prosthetic impingement after THA is to different for the angle and shape of the implant. Purpose of this study is examine the range of motion(ROM) on a computer when angle and shape of the implant are changed. The 3D implant models were created on a computer. The angle was measured in the flexion, extension, adduction direction byevery 0.1 degrees. There are three kinds of acetabular abduction angle, two kinds of