Planning Of Total Hip Replacement Research Articles

Translated article] Correlation between femoral version and severity of hip dysplasia in patients with advanced osteoarthritis prior to total hip arthroplasty

IntroductionDevelopmental dysplasia of the hip (DDH) is a condition which comprises a number of joint abnormalities, including modifications in femoral version and neck-shaft angle (CCD), as well as a probable progression to osteoarthritis in certain cases. The main objective of this research was to find a correlation between femoral version and severity of DDH in patients with advanced osteoarthritis prior to joint replacement, which has not been previously reported. A secondary aim was to describe the modification of CCD as the severity of DDH increases. Materials and methodPatients over the age of 15 with dysplastic hips and severe osteoarthritis prior to total hip arthroplasty were assessed between March 2018 and February 2019. Cases with any previous hip surgery were excluded. Anteroposterior pelvis X-rays and femoral computed tomography (CT) were performed; femoral version was measured in CT and CCD was evaluated both in X-rays (2 observers: A and B) and CT (one observer: musculoskeletal radiologist). Severity of DDH was defined by observers A and B according to Crowe classification in X-rays. Statistical analysis was performed on SPSS v.21. Shapiro–Wilk test was used to confirm a normal data distribution. Intraclass correlation coefficient (ICC) determined the level of agreement between observers A and B. Pearson test assessed the correlation between femoral version and Crowe classification (positive if >0.5). Student's t test evaluated the statistical significance, which was defined as P<0.05. ResultsOne-year assessment; 42 patients (54 hips), 76% women. Mean age 52.7 years. 45 hips completed the imaging set, 9 hips were assessed only with X-rays. 48%, 16%, 7% and 28% were classified as Crowe I, II, III and IV (100% interobserver agreement). Crowe classes were grouped as I, II/III and IV due to a low number of cases classified as II and III. Mean femoral version was 21.73°, 26.8° and 43.58°, respectively. ICC between observers A and B for CCD measured in X-rays was 0.96. Mean CCD measured in X-rays for each group (I, II/III and IV) was 148.11°, 147.7° and 147°, and in CT was 131.21°, 127.9° and 122.14°, respectively. A significant difference was found in femoral version between groups I and IV (P=0.0002) and II/III and IV (P=0.042). Pearson correlation between femoral version and severity of DDH was positive (r=0.52; P=0.0002). A significant difference between CCD measured in CT was found between groups I and IV (P=0.003). ConclusionsA significant increase in femoral version related to severity of DDH and a positive correlation between these 2 features were found. Furthermore, a significant decrease in CCD between groups I and IV measured in CT was revealed. These findings would be helpful for preoperative planning of total hip replacement in osteoarthritis secondary to DDH, because once the surgeon has assessed the severity of DDH on X-rays or CT, an increased femoral version could be expected. Therefore, availability of specific implants such as conic, modular or cemented stems is critical, in order to modify the femoral anteversion to normal values in the most severe cases.

Correlación entre versión femoral y gravedad de displasia del desarrollo de cadera en pacientes con artrosis avanzada

IntroductionDevelopmental dysplasia of the hip (DDH) is a condition which comprises a number of joint abnormalities, including modifications in femoral version and neck-shaft angle (CCD), as well as a probable progression to osteoarthritis in certain cases. The main objective of this research was to find a correlation between femoral version and severity of DDH in patients with advanced osteoarthritis prior to joint replacement, which has not been previously reported. A secondary aim was to describe the modification of CCD as the severity of DDH increases. Materials and methodPatients over the age of 15 with dysplastic hips and severe osteoarthritis prior to total hip arthroplasty were assessed between March 2018 and February 2019. Cases with any previous hip surgery were excluded. Anteroposterior pelvis X rays and femoral computed tomography (CT) were performed; femoral version was measured in CT and CCD was evaluated both in X rays (2 observers: A and B) and CT (one observer: musculoskeletal radiologist). Severity of DDH was defined by observers A and B according to Crowe classification in X rays. Statistical analysis was performed on SPSS v.21. Shapiro-Wilk test was used to confirm a normal data distribution. Intraclass correlation coefficient (ICC) determined the level of agreement between observers A and B. Pearson test assessed the correlation between femoral version and Crowe classification (positive if >0.5). Student's t test evaluated the statistical significance, which was defined as P<0.05. ResultsOne-year assessment; 42 patients (54 hips), 76% women. Mean age 52.7 years. 45 hips completed the imaging set, 9 hips were assessed only with X rays. 48%, 16%, 7% and 28% were classified as Crowe I, II, III and IV (100% interobserver agreement). Crowe classes were grouped as I, II/III and IV due to a low number of cases classified as II and III. Mean femoral version was 21.73°, 26.8° and 43.58°, respectively. ICC between observers A and B for CCD measured in X rays was 0.96. Mean CCD measured in X rays for each group (I, II/III and IV) was 148.11°, 147.7° and 147°, and in CT was 131.21°, 127.9° and 122.14°, respectively. A significant difference was found in femoral version between groups I and IV (P=0.0002) and II/III and IV (P=0.042). Pearson correlation between femoral version and severity of DDH was positive (r=0.52; P=0.0002). A significant difference between CCD measured in CT was found between groups I and IV (P=0.003). ConclusionsA significant increase in femoral version related to severity of DDH and a positive correlation between these 2features were found. Furthermore, a significant decrease in CCD between groups I and IV measured in CT was revealed. These findings would be helpful for preoperative planning of total hip replacement in osteoarthritis secondary to DDH, because once the surgeon has assessed the severity of DDH on X rays or CT, an increased femoral version could be expected. Therefore, availability of specific implants such as conic, modular or cemented stems is critical, in order to modify the femoral anteversion to normal values in the most severe cases.

A 3D-printing Bone Model for Surgical Planning of Total Hip Replacement after Failed Triple Pelvic Osteotomy

A 3D-printing Bone Model for Surgical Planning of Total Hip Replacement after Failed Triple Pelvic Osteotomy

Comparison of Two Scaling Methods in Preoperative Digital Templating of Total Hip Replacement: 全髖關節置換術前數位模板測量法中兩種縮放校準方法的比較研究

Background/PurposePreoperative templating is essential for the planning of total hip replacement. Digital templating has gained popularity due to the availability of digital images. Scaling is the critical step that calibrates magnified digital images to the actual dimension, for subsequent digital templating. We compared the accuracy of two scaling methods: (1) radiological marker; and (2) fixed magnification factor. MethodsForty-five postoperative radiographs in 21 patients who had undergone either total hip replacement or hip hemiarthroplasty were evaluated. The sizes of femoral head components in the digital radiographs were estimated using the two scaling methods. The estimated values were then compared to the true values stated in operation records. The absolute error (AE) and relative error (RE) of both scaling methods were calculated and compared. ResultsBoth the mean AE and RE were smaller in Method 2 (fixed magnification factor), and were statistically significant (p < 0.05). ConclusionWe recommend fixed magnification factor as the scaling method for digital templating.

Improving pre-operative planning for complex total hip replacement with a Rapid Prototype model enabling surgical simulation

Pre-operative planning for total hip replacement (THR) is challenging in hips with severe acetabular deformities, including those with a hypoplastic acetabulum or severe defects and in the presence of arthrodesis or ankylosis. We evaluated whether a Rapid Prototype (RP) model, which is a life-sized reproduction based on three-dimensional CT scans, can determine the feasibility of THR and provide information about the size and position of the acetabular component in severe acetabular deformities. THR was planned using an RP model in 21 complex hips in five men (five hips) and 16 women (16 hips) with a mean age of 47.7 years (24 to 70) at operation. An acetabular component was implanted successfully and THR completed in all hips. The acetabular component used was within 2 mm of the predicted size in 17 hips (80.9%). All of the acetabular components and femoral stems had radiological evidence of bone ingrowth and stability at the final follow-up, without any detectable wear or peri-prosthetic osteolysis. The RP model allowed a simulated procedure pre-operatively and was helpful in determining the feasibility of THR pre-operatively, and to decide on implant type, size and position in complex THRs.

Estimation of change of bone structures after total hip replacement using bone remodeling simulation

BackgroundThe principal cause of femoral stem failure is the loosening of the total hip replacement due to bone resorption in the vicinity of the prosthesis (stress shielding). Bone rebuilds its structure continuously according to the daily mechanical stimuli. Therefore, surgical intervention alters the mechanical condition of bone severely. In this study, we propose a method to predict the change of bone structure after total hip replacement using bone remodeling simulation. MethodThe bone–stem complex structure model after total hip replacement was reconstructed based on CT-images used for preoperative planning by orthopedic experts. The bone remodeling simulation was conducted under the daily loading condition using our previous remodeling model, and the average equivalent stresses in the Gruen zone were evaluated. FindingsThe predicted bone loss relevant to stress shielding was consistent to follow-up clinical data. Moreover, the remodeling simulation when using the stems of different size for the same patient could detect the size-dependent change of stress in the Gruen zone. In particular, the zone under the neck of the stem showed significant changes of stress and large bone loss, accompanying the risk of loosening or fracture. InterpretationsPrediction of bone structure changes after total hip replacement gives us significant information for longevity of prosthesis. Simulation results showed that the present computational framework could be considered to have potential in preoperative planning of total hip replacement.

SIMULATION STUDY OF BONE LOSS AFTER TOTAL HIP REPLACEMENT

The preoperative planning for total hip replacement is an aspect crucial for the outcome of operation. In these days, the planning is carried out by referring to medical images in twoor three-dimensions, and the geometrical fitting at the operation is examined in detail a priori. It, however, is not straightforward to examine the mechanical fitting at the stage of preoperative planning. Computational stress and strain analyses are providing some insights for mechanical fitting at the time of operation and for the short term stability but little for the long term mechanical fitting in which the bone loss is a critical feature. This study is designed to explore a biomechanical index to examine the difference of bone loss after total hip replacement based on different feasible plans considered by surgeons, by means of computational biomechanics simulation. Method

Total hip replacement fifteen years after pelvic support osteotomy (PSO): a case report and review of the literature

Treatment of chronic hip instability in children and young adults is challenging. Proximal femoral osteotomy had been suggested to provide pelvic stability and improved abductor function. Total hip replacement after pelvic support osteotomy can be challenging due to altered anatomy due to angulation of the proximal femur in both frontal and sagittal planes. This is a 29-year-old woman who had total hip replacement after pelvic support osteotomy. The patient had pelvic support at the age of 14 years. Pelvic support osteotomy delayed the need for total hip replacement for 15 years. Preoperative planning for total hip replacement with model was used for proper understanding of the anatomy of the proximal femur. Revision of femoral component was necessary due to penetration of the proximal femur. In conclusion, total hip replacement after pelvic support osteotomy is a technically demanding procedure, and careful attention to surgical details is necessary for successful outcome.

A simple and convenient method guide to determine the magnification of digital X-rays for preoperative planning in total hip arthroplasty

Scaling of anteroposterior digital pelvic X-rays with variable magnification is the premise for accurate preoperative planning of total hip replacement with digital templating. Conn's method of placing a marker of known diameter beside the thigh at the level of the femur has been reproduced in many studies and confirmed as one of the most accurate methods. But in our experience, it is inconvenient for radiographers and is not well tolerated by some patients. We modified this method by placing a coin on the radiograph plate. One hundred patients who had undergone hip replacement were enrolled in the study and randomly divided into two groups. The actual diameter of the prosthesis head was taken as the gold standard for assessment of the magnification of the coin in Group A. The coin was within a mean of 117.95% (range 114.37–122.02%) of magnification for male, and 111.71% (range 114.37–120.93%) for female patients. The variation was small and limited, and had no correlation with body shape parameters (i.e. height, weight, BMI). Subsequently, the magnification of the coin was used to correct the measuring scale of the X-rays of the other 50 patients (Group B). Bias did not exceed 1.96 mm during measurement of the prosthesis with a diameter of less than 56 mm, and a range of absolute error of measurements of 56–66 mm (standard deviation, SD, 0.04–3.95 mm). Furthermore, in order to confirm the expressiveness of the modified method, CT scans of another 50 patients were randomly selected. The distance between the rotation center of the hip and the table, which is acknowledged to be a factor which influences magnification of the coin, changed little in response to body shape. Variation in magnification was caused by variation in distance between the rotation center of the hip and the table. The minimal change in distance for patients with different body shape led to easier and more convenient examination, and increased the feasibility of our modified coin method, except in cases where implantation of a very large-sized prosthesis is necessary.

Preoperative planning of total hip replacement using the TraumaCad™ system

Templating is now the standard approach for preoperative planning of total joint replacement and fracture fixation. The aim of this study was to assess the accuracy of new software, TraumaCad™, for preoperative planning for total hip replacement. This software enables the import and export of all picture archiving communication system (PACS) files from local working stations. It can integrate with all PACS systems. We retrospectively reviewed TraumaCad™-generated templates of digitalized preoperative radiographs of 73 consecutive patients. The acetabular component, measured within ± 1 size, was accurate in 65 patients (89%), and the femoral stem design component was accurate in 70 patients (97%). The accuracy of the femoral size was predicted in 57 patients within 1 size (87%) and in 65 patients within 2 sizes (96%) out of 68 patients in the Corail femoral component group. TraumaCad™ successfully predicts the sizes of femoral and acetabular component and easily integrates with all PACS files.

Efficacy of stereoscopic visualization and six degreesof freedom interaction in preoperative planningof total hip replacement

The aim of this study was to assess the accuracy of a six-degrees-of-freedom application for pre-operative planning of total hip replacement in a virtual reality (VR) environment. A test was performed estimating the system inherent accuracy. The users can move objects in the VR environment with an intrinsic accuracy almost four orders of magnitude greater than the object dimension. A second unambiguous and relevant task was defined to assess the accuracy achievable with the interface in a specific planning task. The results were compared with those obtained with 2D interfaces for both the stem and the cup component. The RMSE was assumed as an indicator of the achievable accuracy. The accuracy of the immersive interface was comparable with that achievable with a standard mouse - monitor interface. The users were consistent using the VR interface, confirming the high usability of the new interface and the steep learning curve of users unfamiliar with the new environment. This study has demonstrated that the application of VR environment for pre-operative planning of total hip replacement may help to shorten the duration of the positioning and to yield consistent results even with first-time users.

Hip joint anatomy virtual and stereolithographic reconstruction for preoperative planning of total hip replacement

The purpose of the present work was to develop a tool for preoperatively planning the Total Hip Replacement (THR). Starting from the MR images, the 3D surface model of both the pelvis and the femur was built and the surgical operation was virtually performed. Data coming from gait analysis were added to visualize the physiologic movement of the hip joint. The resulting triangular mesh was sufficiently accurate to allow the building of the stereolithographic model of the joint by means of rapid prototyping technique. The plastic bones allow the user to have an enhanced vision of the surgical procedure to be performed.

Specialised CT scan protocols for 3-D pre-operative planning of total hip replacement

X-ray computer tomography (CT) provides an accurate source of information in orthopaedics. Many computer aided orthopaedic surgery systems are based on CT images; thus, obtaining high resolution images is important. However, this may result in an excessive radiation dose for the patient. This study is aimed at developing a special CT scanning protocol for the hip region that can be adopted in clinical practise for 3-D pre-operative planning of total hip replacement surgery. Optimisation of CT acquisition parameters is investigated for both axial and spiral CT and the two resulting protocols are compared in terms of effective radiation dose to the patient. Results show that spiral CT with D=3 and P=1.5 in regions with higher morphological and density gradients and D=5 and P=1.5 in regions where the morphology is more regular degrades the image quality slightly but allows acquisition of a higher number of images at comparable costs, increasing the longitudinal resolution of the acquired data set. The effective dose is comparable to that of a standard pelvic CT exam. Adjusting the axial CT scan parameters the effective dose can be reduced, however lowering the accuracy of 3-D bone geometry reconstruction.

Efficacy of fully 3D monomodal interface in pre-operative planning of total hip replacement

Virtual reality (VR) has been applied to many industrial application fields in recent years. Due to the great improvements of computer science and to the lowering of computational costs, some specialised VR approaches have been recently proposed in medicine. The most important VR medical applications are in training and education, but VR has been also used in Computer-Aided Surgery (CAS) systems, for preoperative planning and surgical simulation. The aim of this work is to assess the accuracy of a VR interface for preoperative planning of total hip replacement (THR) based on stereoscopic display and a 6DOF tracker and compare it with the accuracy achieved by traditional mouse–monitor interfaces. The positioning accuracy achievable with the 3D interface is comparable with that achievable with an interface based on the multiplanar reformation representation, in which the patient's anatomy is visualised by means of a three-pane window showing orthogonal 2D cross sections. Using a fully 3D interface, however, the users are much more consistent and repeatable.

Automated CT-based 3D surgical planning for total hip replacement: a pilot study

At the preoperative planning stage of CT-based computer-assisted total hip replacement, a surgeon determines the parameters such as size, position, and orientations of the implants based on interactive visualization of 3D models of the implants and hip joint bone. However, the parameters depend on surgeon's visual assessment of spatial relationship between the hip joint bone and implants. Our objective is to investigate objective criteria for determination of the optimal parameters and formulate an automated determination procedure based on the criteria. We objectified expertise in the preoperative planning of an experienced surgeon into quantitative evaluations and geometrical constraints, then formulated the automated procedure as an optimization problem. The automated planning system was applied to three cases of patient data sets and compared with an experienced surgeon. In the preliminary results, the planning parameters determined by the system were generally acceptable as a pilot experiment.

The value of preoperative planning for total hip arthroplasty

To analyse the value and accuracy of preoperative planning for total hip replacement (THR) we digitised electronically and compared the hand-sketched preoperative plans with the pre- and postoperative radiographs of 100 consecutive primary THRs. The correct type of prosthesis was planned in 98%; the agreement between planned and actually used components was 92% on the femoral side and 90% on the acetabular side. The mean (± SD) absolute difference between the planned and actual position of the centre of rotation of the hip was 2.5 ± 1.1 mm vertically and 4.4 ± 2.1 mm horizontally. On average, the inclination of the acetabular component differed by 7 ± 2° and anteversion by 9 ± 3° from the preoperative plans. The mean postoperative leg-length difference was 0.3 ± 0.1 cm clinically and 0.2 ± 0.1 cm radiologically. More than 80% of intraoperative difficulties were anticipated. Preoperative planning is of significant value for the successful performance of THR.

Preoperative planning for primarytotal hip arthroplasty

Preoperative planning for total hip replacement (THR) takes place at the institutional, physician practice, and individual case levels. Patient-implant demand matching and the development of critical pathways for postoperative care are essential to the continued practice of THR in today's health care environment. Preoperative patient education speeds recovery, provides realistic expectations, and enhances the durability of the arthroplasty. Prospective evaluation of patient outcomes enables rationale assessment of new technologies and confirms the cost-effectiveness of THR in enhancing quality of life. Successful THR for a given individual demands a comprehensive assessment and optimization of the patient's general medical status. The orthopaedic evaluation focuses on leg lengths, contractures, and coexisting musculoskeletal abnormalities. appropriate preoperative radiographs are essential. Implants must be selected to optimize component fit and fill (intraosseous considerations) as well as leg length, offset, and anteversion (extraosseous relationships).The surgeon should have not only a primary intraoperative plan, but alternative plans, implants, and instruments to deal with unexpected findings or complications.