Background. Accurate
INTRODUCTION. Additive manufacturing (3D printing) is used to create porous surfaces that promote bone ingrowth in an effort to improve initial stability and optimize long-term biological fixation. The
The angle of acetabular inclination is an important measurement in total hip replacement (THR) procedures. Determining the acetabular component orientation intra-operatively remains a challenge. An increasing number of innovators have described techniques and devices to achieve it. This paper describes a mechanical inclinometer design to measure intra-operative
INTRODUCTION. Unlike current
Lewinnek's safe zone recommendation to minimise dislocations was a target of 5–25° for anteversion angle and 30–50° for inclination angle. Subsequently, it was demonstrated that mal-positioning of the
Introduction. Proper
Introduction: In vitro studies have shown that low clearance bearings have the potential to generate low wear. However, cementless
Dislocation after total hip arthroplasty (THA) remains a significant clinical problem. The
Introduction. Ultra-high molecular weight polyethylene (UHMWPE) is the sole polymeric material currently used for weight- bearing surfaces in total joint replacement. However, the wear of UHMWPE in knee and hip prostheses after total joint replacement is one of the major restriction factors on the longevity of these implants. In order to minimize the wear of UHMWPE and to improve the longevity of artificial joints, it is necessary to clarify the factors influencing the wear of UHMWPE. A number of studies have investigated the factors influencing the wear of UHMWPE
Purpose. Cementless cup with structural allograft is one of option for acetabular revision in the cases which has severe bone loss. This study was performed to verify that the structural allograft with cementless cup could be one of good options for revision of
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
Introduction. Recent gains in knowledge reveal that the ideal
Introduction. Modern
INTRODUCTION. Poor
Introduction. Component positioning is of great importance in total hip arthroplasty (THA) and navigation systems can help guide surgeons in the optimal placement of the implants. We report on a newly developed navigation system which employs an inertial measurement unit (IMU) to measure
Abstract. Objectives. The importance of cup position on the performance of total hip replacements (THR) has been demonstrated in in vitro hip simulator tests and clinically. However, how cup position changes during gait has not been considered and may affect failure scenarios. The aim of this study was to assess dynamic cup version using gait data. Methods. Pelvic movement data for walking for 39 unilateral THR patients was acquired (Leeds Biomedical Research Centre). Patient's elected walking speed was used to group patients into high- and low-functioning (mean speed, 1.36(SD 0.09)ms. −1. and 0.85(SD 0.08)ms. −1. respectively). A computational algorithm (Python3.7) was developed to calculate cup version during gait cycle. Inputs were pelvic angles and initial cup orientation (assumed to be 45° inclination and 7° version, anterior pelvic plane was parallel to radiological frontal plane). Outputs were cup version angles during a gait cycle (101 measurements/cycle). Minimum, maximum and average cup version during gait cycle were measured for each patient. Two-sample t-test (p=0.05) was used to compare groups. Results. Over a gait cycle the mean minimum, maximum and average version angles for the high-functioning group were −4.5(SD 4.4)°, 5.0(SD 4.3)°, 9.5(SD 4.0)° and for low-functioning group 2.0(SD 3.7)°, 6.2(SD 2.9)°, 8.1(SD 3.2)°. There were no significant differences for the minimum, maximum and average version angles between the two groups. Conclusions. The study shows that dynamic
Introduction. Aseptic loosening of the
Positioning of the hip resurfacing is crucial for its long term survival and is critical in young patients for some reasons; manly increase the wear in the components and change the load distribution. THR have increased in the last years, mainly in young patients between 45 to 59 years old. The resurfacing solution is indicated for young patients with good bone quality. A long term solution is required for these patients to prevent hip revision. The resurfacing prosthesis Birmingham Hip Resurfacing (BHR) was analyzed in the present study by in vitro experimental studies. This gives indications for surgeons when placing the
Objective. The purpose of this study was to investigate how rim poly locking scallop cutting depth could affect the rigidity of
Introduction. Robotic-assisted hip arthroplasty helps acetabular preparation and implantation with the assistance of a robotic arm. A computed tomography (CT)-based navigation system is also helpful for acetabular preparation and implantation, however, there is no report to compare these methods. The purpose of this study is to compare the
Purposes. To compare the acetabular component size relative to the patient's native femoral head size between conventional THA (CTHA) approach and robotic-guided THA (RGTHA) to infer which of these techniques preserves more acetabular bone. Methods. Patients were included if they had primary osteoarthritis (OA) and underwent total hip replacement between June 2008 and March 2014. Patients were excluded if they had missing or rotated postoperative anteroposterior radiographs. RGTHA patients were matched to a control group of CTHA patients, in terms of pre-operative native femoral head size, age, gender, body mass index (BMI) and approach.
Objectives. Porous metal surfaces have been a popular option for acetabular component fixation in total hip arthroplasty (THA). New THA component designs are introduced periodically with the expectation of better wear properties and survivorship. Since its approval for use in 2002 there have been few clinical outcome studies published on the Pinnacle
Metal on metal press-fit
Total hip replacement (THR) is one of the most successful orthopedic operations, yet it continues to be plagued with problems despite the many advances in the procedure. Inconsistent placement of the
Following hip arthroplasty carried out using the Slooff-Ling impaction grafting technique micro-motion of the
Introduction. Proper cup positioning is a critical component in the success of total hip arthroplasty surgery. A multicenter study has been initiated to study a new type of highly cross-linked polyethylene. This study provides a unique opportunity to a review the
Initial stability of cementless components in bone is essential for longevity of Total Hip Replacements. Fixation is provided by press-fit: seating an implant in an under-reamed bone cavity with mallet strikes (impaction). Excessive impaction energy has been shown to increase the risk of periprosthetic fracture of bone. However, if implants are not adequately seated they may lack the stability required for bone ingrowth. Ideal fixation would maximise implant stability but would minimise peak strain in bone, reducing the risk of fracture. This in-vitro study examines the influence of impaction energy and number of seating strikes upon implant push-out force (indicating stability) and peak dynamic strain in bone substitute (indicating likelihood of fracture). The ratio of these factors is given as an indicator of successful impaction strategy. A custom drop tower with simulated hip compliance was used to seat
Introduction: Correct placement of the
Introduction:. The lateral radiographs are useful in evaluation of the
Originally introduced in 1997, porous tantalum is an attractive alternative metal for orthopaedic implants because of its unique mechanical properties. Porous tantalum has been used in numerous types of orthopaedic implants, including
Introduction. Durable bone fixation of uncemented porous-coated
We measured the proximal migration of 265
In laboratory tests, the ultra-high molecular weight polyethylene used for the
Aims: Given that all previous reports on the increased-crystalinity, increased modulus of elasticity, yield strength and density Hylamer polyethylene have been based on observations on uncemented metal-backed
We examined radiographic polyethylene wear in 233 cemented total hip arthroplasties (201 patients) with either a metal-backed or a non-metal-backed
Background. Trust in the validity of a measurement tool is critical to its function in both clinical and educational settings.
Introduction. Appropriate
Introduction. Durable bone fixation of uncemented porous-coated
Introduction: Hip resurfacing is a successful pain-relieving procedure which restores function in young patients. However, some patients have persisting pain. We suggest that load characteristics in relation to position of the cup may influence these symptoms. We aimed to determine the effect of
Iliopsoas tendonitis after total hip arthroplasty (THA) can be a considerable cause of pain and patient dissatisfaction. The optimal cup position to avoid iliopsoas tendonitis has not been clearly established. Implant designs have also been developed with an anterior recess to avoid iliopsoas impingement. The purpose of this cadaveric study was to determine the effect of cup position and implant design on iliopsoas impingement. Bilateral THA was performed on three fresh frozen cadavers using oversized (jumbo) offset head center revision
INTRODUCTION. Total hip arthroplasty (THA) is regarded as one of the most successful surgeries in medicine. However, recent studies have revealed that ideal
Revision hip arthroplasty for severe acetabular deficiency is a technically challenging operation. Many different methods have been described for the management of acetabular deficiency. These include augmentation with bone cement, structural allografts, impaction grafting, support rings with graft and reconstruction with a high centre of rotation. The long term results of many of these methods were variable. We reviewed the outcome of a stemmed
Since the autumn of 2003, a computer-assisted system (VectorVision® Hip, version 2.1, Brain LAB, Germany) has been used to perform total hip arthroplasty (THA) operations in our hospital. In the present study, the postoperative
Introduction: Tantalum Monoblock
Introduction. The National Joint Registry of England, Wales, Northern Ireland, and the Isle of Man (NJR) monitors the performance of primary total hip arthroplasty (THA) implants and summarizes usage and outcomes for specific hip systems. The objectives of this study were to 1) determine if survivorship for the PROCOTYL® L
Introduction: Malpositioning of the
We wanted to solve the problem of acetabular dysplasia with a cementless total hip endoprothesis by using a smaller
Objectives. Total hip replacement is increasingly being conducted in younger and more active patients, so surgeons often use bearing surfaces with improved wear characteristics, such as ceramic on ceramic. The primary objective of this study was to determine if survivorship for a BIOLOX® delta ceramic on delta ceramic couple used with the PROCOTYL® L
One of important issues of concern in total hip arthroplasty (THA) is osteolysis due to wear debris of ultra-high molecular weight polyethylene (PE), and it often leads to aseptic loosening. Reduction of PE wear debris is essential to prevent osteolysis, and different bearing interfaces as well as improvement of the bearing material itself have been attempted. Alumina ceramics as the bearing material for THA was introduced in Europe and Japan in the 1970s in aim to reduce the PE wear debris. The clinical results have proved the superiority of ceramic on PE couples to metal on PE couples in wear resistance. PE materials cross-liked by irradiation have also demonstrated a significant low wear by in vitro studies. Several types of highly cross-linked polyethylene (CLPE), with the irradiation dose of 50 to 105 kGy, have been developed and extensively used since 1998. In this study, the in vivo wear and oxidation of CLPE
Optimal alignment of the
INTRODUCTION. Dislocation is one of the most important complications in THA. Dual mobility cup (DMC) inserts reduce the risk for dislocation after total hip arthroplasty by increasing the oscillation angle. A lower rate of dislocation with use of a DMC insert has been reported in different studies. But there is no available research that clearly delineates the stability advantages of DMC inserts in primary THA. The aim of our study was to evaluate the area of the safe zone for a DMC insert, compared to a fixed insert for different anteversion angles of the femoral component. Material and Methods. A model of the pelvis and femur were developed from computed tomography images. We defined the coordinate system of the pelvis relative to the anterior pelvic plane and the coordinate system of the femur relative to the posterior condylar plane. In our model, we simulated a positive anteversion position of the
Cup implantation is a critical stage during THR Surgery. It is mainly because of the rudimentary mallet-based impaction technique, whereby mal-positioning and unknown forces are present. There are some technological attempts to solve this problem partially: dealing with mal-positioning while patient remains subjected to non-standardized impaction forces. Our comprehensive approach to the problem allows the surgeon to monitor cup positioning and perform controlled insertion with a completely known force profile. Positioning is monitored by means of IMU (Inertial Measurement Unit) technology, while placement is controlled by force feedback and vibratory insertion device. Both technological building blocks (IMU and vibratory insertor) are embedded on a single device containing signal processing and automatic control strategies. This mechatronic device is called BMD3. This work covers the entire device development life cycle illustrated in figure 1: the roadmap starts at the conceptual inspiration through scientific investigation and concept proof/demonstration up to the BMD3 prototype. Smooth insertion was the main purpose initially; this led to concept demonstration by means of electrical and pneumatic actuated devices. They employ low-amplitude/high-frequency vibratory input forces into the
Purpose:. Correct placement of the
Introduction. Total hip arthroplasty is considered to be one of the most successful orthopaedic interventions. Acetabular component positioning has been shown to affect dislocation rates, component impingement, bearing surface wear rates, and need for revision surgery. The safe zones of acetabular component positioning have previously been described by Lewinnek et al. as 5 to 25 degrees of cup version and 30 to 50 degrees of inclination. Callanan et al. later modified the inclination to 30 to 45 degrees. Our aim was to assess whether THA via robotic assisted posterior approach (PA) improves acetabular component positioning compared to fluoroscopic guided anterior approach THA (AA). Methods. Subjects. This study is a matched-pair case-control study using prospectively collected data from THAs done between January 2012 and December 2013. Patients who underwent primary THA using the PA or AA by the senior surgeons (MH and JAR) were included in the study. Ninety-six patients (of 176; 55%) underwent AA and 80 (of 176; 45%) underwent PA THAs. The matching process was performed by an observer blinded to the radiographic outcomes (EK). Patients were matched for sex and BMI +− 8 units. Seventy-nine patients who had AAs were manually matched to 79 patients who had PAs. Surgical Techniques. For the AA THAs, the patient is supine and the approach is performed through a modified smith Peterson approach.
Between March 1990 and May 1991 we performed 85 primary total hip replacements in 74 patients using the Landos Atoll hydroxyapatite (HA)-coated cup and the Corail HA-coated stem. The patients were followed up for a mean of ten years. Of the 85 cups, 26 (31%) have already been revised and a further six are radiologically unstable and awaiting revision. Two femoral stems have been revised for infection without loosening. The retrieved
Fracture of the polyethylene
Purpose. The aim of the study was to assess the efficacy of a cementless
Introduction: The Opera
Purpose:. Malpositioning of the
The existing image-free Total Hip Arthroplasty (THA) navigation systems conventionally utilise the patient-specific Anterior Pelvic Plane (APP) as the reference to calculate orientations of the implanted cup, e.g. anteversion and inclination angles. The definition of APP relies on the intra-operative digitisation of three anatomical landmarks, the bilateral Anterior Superior Iliac Spine (ASIS) and the pubicum. Due to the presence of the thick soft tissue around the patient's pubic region, however, the landmark on pubic area is hard to be digitised accurately. A novel reference plane called Intra-operative Reference Plane (IRP) was proposed by G. Zheng et al to address this issue. To determine the IRP, bilateral ASIS and the cup center of the operating side instead of the pubicum are digitised intra-operatively. It avoids the error-prone digitisation of pubicum, and the angle between the patient-specific APP and the suggested IRP can be computed pre-operatively by a single X-ray radiograph-based 2D/3D reconstruction approach developed by G. Zheng et al. Based on this angle, the orientation of the APP can be intra-operatively estimated from that of the IRP such that all measurements with respect to IRP can be transformed to measurements with respect to APP. In order to implement and validate this new reference plane for image-free navigation of
Background. Complications such as dislocations, impingement and early wear following total hip arthroplasty (THA) increase with
1. Prosthetic
Aims:Malpositioning of implant components plays a signiþcant role in instability of THR. Our aim was the determination of the inßuence of anteversion of the
Introduction. Plain radiograph underestimates the lysis extent while bone defect determines acetabu-lar revision. We determine the multislice computed tomography (CT) efficacy with metal-artifact minimization to calculate the volume, extent and location of lytic lesions around a loose
Introduction. Plain radiograph underestimates the lysis extent while bone defect determines acetabular revision. We determine the multislice computed tomography (CT) efficacy with metal-artifact minimization to calculate the volume, extent and location of lytic lesions around a loose
Laboratory wear testing of ultra high molecular weight polyethylene from 12 Charnley
Hydroxyapatite-coated
Introduction. Iliopsoas tendonitis after total hip arthroplasty (THA) can be a considerable cause of pain and patient dissatisfaction. The optimal cup position to avoid iliopsoas tendonitis has not been clearly established. Implant designs have also been developed with an anterior recess to avoid iliopsoas impingement. The purpose of this cadaveric study was to determine the effect of cup position and implant design on iliopsoas impingement. Materials. Bilateral THA was performed on three fresh frozen cadavers using oversized (jumbo) offset head center revision
Purpose:. Imageless navigation has improved the accuracy of
Malpositioning of the
Introduction: Trabecular metal associated with monob-lock elliptical design represents a valid surgical solution for orthopaedic acetabular reconstructive procedures and second surgery. Materials and methods: From 1999 to 2004, 61 patients between 45 and 81 years with osteoathritis underwent total hip primary arthroplasties with porous tantalum elliptical cup. We performed clinical evaluation through Harris Hip Score test. Bone-implant interface was studied through radiography with reference to the three Charnley’s areas. Follow-up were performed preoperatively at six months and yearly thereafter. Results: Clinical results showed high improvement of Harris Hip Score (average preoperatively score was 46, postoperatively 90). Radiographic evaluation revealed a bone apposition to the porous tantalum without radiolucent lines around the acetabular interface. No local (osteolysis) or general (DVT) complication was seen. Conclusions: Tantalum monoblock elliptical
We report the long-term radiological results of 58 total hip arthroplasties (THA) using the Charnley offset-bore acetabular socket. Wear was measured at four sites and radiolucent lines and possible migration were recorded. Four cups were retrieved at revision and were examined using light microscopy, SEM and X-ray microanalysis. At a mean follow-up of seven years the mean wear in the DeLee and Charnley zone I was 0.4 mm and in zone II 0.26 mm. The wear rate was 0.06 and 0.04 mm/year, respectively. Progression of radiolucent lines was seen in five cases (8.6%). Three sockets (5.2%) were revised because of aseptic migration at a mean follow-up of 9.8 years and one socket for infection at two years. The offset-bore
We describe a new method for the accurate measurement of the angle of anteversion of an
Obtaining consistently an optimal cup orientation in THA is vital to obtain adequate head coverage and maximum impingement free range of motion and thus reduce the incidence of polyethylene wear, cup loosening, and dislocation rates associated with a limited range of motion. It is clear that THA instability, the most frequent cause of early failure, is a complex problem related to a wide range of causes. However cup orientation is one of the surgeon dependant potentially modifiable variables that continue to have an important influence due to the lack of reliable means of assuring an adequate orientation of the components, particularly the cup anteversion. Standard mechanical guides like Muller’s have been shown to be inaccurate and imprecise. Not surprisingly, dislocation is the most frequent short term complication after a THA.
Introduction.
Failure of an
Introduction. Computer-assisted methods for acetabulum cup navigation have shown to be able to improve the accuracy of the procedure, but are time-consuming and difficult to use. The goal of this project was to develop an easy-to-use navigation technique, requiring minimal equipment for
Purpose of the study: Dislocation of total hip arthroplasty remains a frequent complication, occurring for 0.5% to 10% of implants depending on the series. In about 30% of the cases, the orientation of the
Ten
Introduction. In total hip arthroplasty, the positioning of the
Reconstruction following internal hemipelvectomy for bone tumors remains a major surgical challenge. Most of the cases are considered not suitable for reconstruction because of high complication occurrence. Allografts coupled with standard prosthesis is a reliable method of reconstruction. 26 patients received a McMinn stemmed cup (Link, Germany) after periacetabular tumor resection from February 1999 to 2006. In 18 patients the reconstruction followed resection of the acetabular area while in other 8 an extrarticular resection of the proximal femur was performed. In 21 cases a stemmed
Malorientation of the
A novel CT-free image-guided navigation system for
Introduction: Many designs exist for the femoral component of cemented total hip arthoplasty, but cemented
In total hip arthroplasty (THA), cementless cup without screw holes has the putative benefits of maximizing host bone contact and reducing osteolysis by eliminating channels to backside wear particles. However, supplemental trans-acetabular screws cannot be used. 74 hips in 60 patients receiving same model of cementless cup without screw holes (Depuy Duraloc 100 HA cup) from 6/1999 to 3/2003 were prospectively followed up. All patients were allowed to have immediate full weight bearing. Age at THA was 53 ± 13 (range 24–74) years. Osteonecrosis was the leading hip disease (45% of hips). Survivorship was assessed using revision of the cup as the end point. Radiological parameters, including lateral opening angle, vertical and horizontal migration distances of the cups were measured. Paired t-test was used to compare between the measurements in early postoperative period and at final follow up. 51 hips were assessed at minimum 20 years follow-up. The mean follow-up was 22.6 (range 21 – 25) years. All the cups were well fixed. There were two cup revisions. Conventional polyethylene (PE) was used in both hips; osteolysis occurred 17 and 18 years later. Both cups were well fixed but were revised, one due to cup mal-positioning, one due to need in upsizing the articulation. 14 other hips were revised but these cups were well fixed and not revised; 9 loosened stems (most were cemented Elite plus stems), 5 PE wear and osteolysis (all were conventional PE). At 20 years, the survivorship of cups was 96.1%. Changes in lateral opening angle, vertical and horizontal migration distances were 0.44±1.59°, 0.01±1.52mm and -0.32±1.47mm respectively, without statistical significance. This study provided evidence of excellent long-term survivorship of cementless cup without screw holes. Immediate postoperative weight-bearing also did not lead to cup migration in the long-term.
Background: The purpose of this prospective study was to asses the reliability of image-free navigated cup positioning and its correlation with biometrical parameters (age, sex, body mass index, soft tissue thickness overlying anterior superior iliac spine and symphysis pubis, and lumbar lordosis) and three different orientations of pelvis (tilt, obliquity, and rotation) in patients of Asian ethnicity. Methods: Intraoperative data was obtained from 50 consecutive total hip arthroplasties in which
Introduction. The goal of total hip arthroplasty (THA) should be to reconstruct the acetabulum by positioning the hip center as close as possible to the anatomical hip center. However, the true position of the anatomic hip center can be difficult to determine during surgery on an individual basis. In 2005, we designed, produced an acetabular reaming guide, and clinically used to enable cup placement in the ideal anatomical position. This study was examined the accuracy the reaming guide for THA in prospective study. Methods. This guide was applied consecutive 230 patients in primary THA. During planning, the distance from the acetabular edge to the reaming center and from the center to the perpendicular of the inter-teardrop line was measured on an anteroposterior (AP) X-ray. The reaming guide was adjusted depend on the reaming center by based planning. Acetabular reaming was performed with the process reamer. Results. At planning, the position of the hip center was 18.1 mm in the vertical offset (VO) and 29.6 mm in the horizontal offset (HO). After surgery, the position of the hip center had a VO of 18.1 mm and an HO of 29.9 mm. The absolute error between planning and post-operation was a VO of 2.7 mm and an HO of 2.9 mm. Overall, 199 cases (86.5%) had an HO error of less than 5 mm and 204 cases (89.6%) had a VO error of less than 5 mm. The vertical height from the teardrop line to the inferior edge of the
Achieving the correct inclination angle for the acetabular component in total hip arthroplasty (THR) can be technically challenging. The aim of this study is to validate the use of a simple, laser-guided system to address the
Aim: Evaluate a novel horseshoe shaped cup designed by the senior authors to minimise the resection of healthy bone in total hip arthroplasty. Method: Fifty female patients with a displaced, subcapital, femoral neck fractures were chosen for the study. In half of the group of patients, the composite support shell was coated with HA, with the other half remaining uncoated. Clinical and radiological assessments were undertaken regularly for 5 years. Results: To date 20 patients have died and 13 have withdrawn from the study due to poor medical health unrelated to the study. Charnley modified Merle d’Aubigne score at 5 years was as good as the preoperative score with 80% of patients having full range of movement, no pain and walking unaided. Radiographic results showed no evidence of loosening of HA coated cups, in contrast to non HA coated cups which migrated significantly in 80% of cases. Four patients with loose non HA coated cups underwent revision surgery. Conclusion: It replaces the cartilage and underlying sub-chondral bone of the acetabulum socket with a cup that is designed to flex in harmony with the surrounding bony structure. This trial has demonstrated success at 5 years with the HA coated Cambridge
The novel horseshoe shaped cup was designed by the senior authors to minimise the resection of healthy bone in total hip arthroplasty. It replaces the cartilage and underlying sub-chondral bone of the acetabulum socket with a cup that is designed to flex in harmony with the surrounding bony structure. Fifty female patients with a displaced, subcapital, femoral neck fractures were chosen for the study. In half of the group of patients, the composite support shell was coated with HA, with the other half remaining uncoated. Clinical and radiological assessments were undertaken regularly for five years. To date 20 patients have died and 13 have withdrawn from the study due to poor medical health unrelated to the study. Charnley modified Merle d’Aubigne score at five years was as good as the preoperative score with 80% of patients having full range of movement, no pain and walking unaided. Radiographic results showed no evidence of loosening of HA coated cups, in contrast to non HA coated cups which migrated significantly in 80% of cases. Four patients with loose non HA coated cups underwent revision surgery. This trial has demonstrated success at 5 years with the HA coated Cambridge
Achieving optimal
After experimental and preclinical evaluation (HAP Paul Award 2001) of a CT-free image guided surgical navigation system for
Aim: To determine the incidence of periacetabular osteolysis in an uncemented, press-fit, one-piece, titanium plasma spray backed
The purpose of this study was to examine the utility of the acetabular component introducer as a tool to intra-operatively predict implant inclination in total hip arthroplasty. This study investigated (1) the correlation between intra-operative photographic assessment of cup inclination using the acetabular introducer and that measured on post-operative radiograph; and (2) the accuracy of intra-operative prediction of abduction angle. For this study, we prospectively recruited 56 patients scheduled to receive primary hip arthroplasty from one of two senior surgeons. During the procedure, the lead surgeon provided a prediction of the abduction angle based on the alignment of the impactor attached to the cup in its final seated position. A standardized anteroposterior (AP) photograph was then taken of the acetabular impactor in situ. Abduction angles were measured by two observers on the photographs and post-operative AP pelvis radiographs. Linear regression was used to determine the correlation between the angle of the guide measured on the photographs and the actual position of the implant measured on the radiograph. Descriptive statistics were further used to analyze the accuracy of the intra-operative prediction as compared with the abduction angle measured on the photographs. Measurements of cup position made from post-operative radiographs were significantly correlated with the measurements as assessed by intra-operative photographs (r = 0.34, p = 0.00). Our findings demonstrate that radiological abduction angles tend to be greater than that assessed by intra-operative photographs by a mean of 5.6 degrees (SD = 6.6 degrees; 95% CI = 7.3 to 3.9 degrees). Conversely, surgeon prediction of cup inclination based on the acetabular introducer differed from the radiographic measurements by a mean of 6.8 degrees (SD = 8.7 degrees). There was good agreement between the two observers in both photographic and radiographic measurement (k = 0.95, k = 0.96, respectively). In conclusion, we found that the intra-operative photographic assessment of
Prosthetic reconstruction of high-riding hips is technically demanding. Insufficient bony coverage and osteopenic bone stock frequently necessitate transacetabular screw fixation to augment primary stability of the metal shell. We sought to determine the validity of the previously reported quadrant system, and if needed, to define a specialized safe zone for augmentation of screw fixation to avoid vascular injuries in
Different types of highly cross-linked polyethylene (HXLPE) have been introduced widely in
Background. The accuracy of cup placement in navigated THA depends on the bony landmark registration intraoperatively. The usual patient position for registration is supine, but supine position has some drawbacks such as it's more difficult for femoral canal visualisation. The alternate patient position is lateral decubitus, but registration in this position may be unreliable because of the contralateral ASIS can't be palpated accurately. The other technique is registration in supine position first and then placing the patient in lateral decubitus for operation. The drawbacks of this technique are time consumption and increased risk of contamination. We created a semilateral decubitus position which combined the advantage of supine position for registration and lateral decubitus position for better femoral canal visualisation. We modified the registration technique by compressing the soft tissue above Pubic Symphysis(PS) to the abdomen and registered at the Antero-Superior-Pubic-Symphysis(ASPS). Objective. Evaluate the accuracy of cup placement within the “safe zone” and the accuracy of imageless navigation measurement by comparing the intraoperative values of
In a prospective and randomised clinical study,