An Automated Size Recognition Technique for Acetabular Implant in Total Hip Replacement

Preoperative templating in Total Hip Replacement (THR) is a method to estimate the optimal size and position of the implant. Today, observational (manual) size recognition techniques are still used to find a suitable implant for the patient. Therefore, a digital and automated technique should be developed so that the implant size recognition process can be effectively implemented. For this purpose, we have introduced the new technique for acetabular implant size recognition in THR preoperative planning based on the diameter of acetabulum size. This technique enables the surgeon to recognise a digital acetabular implant size automatically. Ten randomly selected X-rays of unidentified patients were used to test the accuracy and utility of an automated implant size recognition technique. Based on the testing result, the new technique yielded very close results to those obtained by the observational method in nine studies (90%)

Templating Hip Arthroplasty

BACKGROUND: Different methods have been developed and employed with variable degrees of success in pre-operative templating for total hip arthroplasty. Preoperative templating, especially digital templating, has been claimed to have increased the effectiveness of total hip arthroplasty by improving the precision of prediction of prosthetic implant size. AIMS: The overall aim of this systematic review is to identify whether the use of pre-operative templating in total hip arthroplasty procedures has resulted in increased accuracy, reliability and precision of the procedure. Various methods of templating, like traditional acetate overlay and digital method of templating that includes a single radiographic marker and double radiographic marker methods, have been compared to establish the most reliable method of templating. METHODS: We searched the PubMed, Google Scholar Cochrane Central Register of Controlled Trials (CENTRAL), and MEDLINE (1966 to present), EMBASE (1980 to present), CINAHL (1982 to present), Psych INFO (1967 to present) and Clinical Trials Gov. CONCLUSION: The results of this systemic review suggest that preoperative templating is resulting in an enormous increase in the accuracy of total hip arthroplasty and among various methods, King Mark is the most reliable method

Computer aided preoperative planning application for shoulder hemiarthroplasty

This paper describes a proposed CAD graphics application that analyze digital radiography image for preoperative surgery in shoulder hemiarthroplasty.The purpose of designing this application is to aid orthopedic surgeon in preoperative planning phase before surgery, in terms of selecting suitable implant and manipulating the digital radiograph by using various facilities or tools available in the application. Therefore, digital templating and image processing play important roles in this research. Basically this application will support a few types of image file including jpg, gif, bmp and etc to be loaded. It will allow image enhancement and also enable measurement tools to be used by surgeon during the preoperative phase. A user will only need to do 5 simple steps in order to get the appropriate template and finally generate reports that he requires

Comparison of the Accuracy of 2D and 3D Templating for Revision Total Hip Replacement

Introduction: Revision hip arthroplasty is a challenging surgical procedure, especially in cases of advanced acetabular bone loss. Accurate preoperative planning can prevent complications such as periprosthetic fractures or aseptic loosening. To date, the accuracy of three-dimensional (3D) versus two-dimensional (2D) templating has been evaluated only in primary hip and knee arthroplasty. Methods: We retrospectively investigated the accuracy of 3D personalized planning of reinforcement cages (Burch Schneider) in 27 patients who underwent revision hip arthroplasty. Personalized 3D modeling and positioning of the reinforcement cages were performed using computed tomography (CT) of the pelvis of each patient and 3D templates of the implant. To evaluate accuracy, the sizes of the reinforcement cages planned in 2D and 3D were compared with the sizes of the finally implanted cages. Factors that may potentially influence planning accuracy such as gender and body mass index (BMI) were analyzed. Results: There was a significant difference (p = 0.003) in the accuracy of correct size prediction between personalized 3D templating and 2D templating. Personalized 3D templating predicted the exact size of the reinforcement cage in 96.3% of the patients, while the exact size was predicted in only 55.6% by 2D templating. Regarding gender and BMI, no statistically significant differences in planning accuracy either for 2D or 3D templating were observed. Conclusion: Personalized 3D planning of revision hip arthroplasty using Burch Schneider reinforcement cages leads to greater accuracy in the prediction of the required size of implants than conventional 2D templating

A New Digital Preoperative Planning Method for Total Hip Arthroplasties

Preoperative templating is an important part of a THA. The ability to accurately determine magnification of the hip on the radiograph and apply identical magnification to the radiograph and template will improve accuracy of preoperative templating of THA. We designed a templating method using a new way of determining the hip magnification with a linear relationship between magnification of the hip and the reference object on top of the pubis symphysis; the relationship was determined on 50 radiographs. We then compared our method with two other templating methods: an analog method assuming an average hip magnification of 15% and a digital method determining the hip magnification with a one-to-one relationship between the reference object and the hip. All methods were reproducible. Uniform undersizing occurred when templating with the digital method based on the one-to-one relationship; the analog method best predicted the implanted prosthesis size, closely followed by our new digital templating method; the new method will be particularly applicable for preoperative THA when analog methods are replaced by digital methods

A New Digital Preoperative Planning Method for Total Hip Arthroplasties

Preoperative templating is an important part of a THA. The ability to accurately determine magnification of the hip on the radiograph and apply identical magnification to the radiograph and template will improve accuracy of preoperative templating of THA. We designed a templating method using a new way of determining the hip magnification with a linear relationship between magnification of the hip and the reference object on top of the pubis symphysis; the relationship was determined on 50 radiographs. We then compared our method with two other templating methods: an analog method assuming an average hip magnification of 15% and a digital method determining the hip magnification with a one-to-one relationship between the reference object and the hip. All methods were reproducible. Uniform undersizing occurred when templating with the digital method based on the one-to-one relationship; the analog method best predicted the implanted prosthesis size, closely followed by our new digital templating method; the new method will be particularly applicable for preoperative THA when analog methods are replaced by digital method

The importance of biomechanical restoration for total hip arthroplasty

Total hip arthroplasty (THA) has become a safe and very successful surgical intervention. A vast majority of patients get their expectations met. Improvement of materials, implant designs, and surgical techniques, have extended prosthetic survival. However, inferior placement and sizing of a hip prosthesis are known to increase the risk of mechanical failure, wear, and early loosening as well as patient dissatisfaction. The main objective of this thesis was to evaluate the importance of improved biomechanical restoration for the function and survival of THA, as well as finding ways of achieving this improvement. We used radiostereometry (RSA), low dose computer tomography (CT) for 3D measurements, 3D templating, prosthetic modularity, and 3D gait analysis, together with patient-reported outcomes. We found a strong correlation between initial postoperative femoral neck anteversion (FNA) and subsequent posterior rotation and loosening of cemented stems. Our 3D measurement techniques showed near-perfect inter- and intraobserver agreements regarding our femoral offset (FO), acetabular offset (AO), and global offset (GO) measurements. We did not see any differences in RSA migration between uncemented modular and standard stem types, both stabilised well with good migration pattern. Postoperative FNA and FO/AO quota had no impact on uncemented stem migration, maybe due to the study being underpowered. The standard stem tended to result in insufficient GO, whereas the modular stem did not. 3D templating was superior in the correct prediction of the final stem size and neck, but 2D templating overestimated stem-size and underestimated neck-length. There was no statistically significant difference regarding cup size predictions. We found an unexpected progressive varus deformation, with concomitant corrosion-related cobalt ion release, from the modular stem-neck junction. However, the ion-concentrations did not correlate with adverse local tissue reaction (ALTR) as measured with MRI up to 8 years. Biomechanical restoration during THA does positively impact the quality of postoperative overall gait pattern, with faster walking speed and with less trunk lean over the affected side. Increased FNA was associated with increased internal hip rotation during walking. An increase in external hip adduction moments was, on the other hand, not associated with a change in FO/AO quota but with a more upright walking position and increased walking speed.Biomechanical restoration is important for THA and our studies confirm the need for precise measuring- and evaluation-tools for this kind of research

Digital Templating and Preoperative Deformity Analysis with Standard Imaging Software

Analysis of deformity and subsequent correction are the basis for many orthopaedic surgical procedures. In advanced cases of joint degeneration, arthroplasty may be the only available treatment option. Until recently, these analyses and preoperative surgical plans have been performed using standard radiographs, tracing paper, and/or plastic overlays. Numerous customized, commercially available, computer-based preoperative planning software programs have been introduced. The purposes of this study were to describe (1) the techniques used in deformity analysis and preoperative surgical planning using standard radiographs for joint arthroplasty and corrective osteotomies of the extremities, (2) the use of computed tomography (CT) scans to analyze rotational deformities in the presence and absence of joint prostheses and in planning corrective rotational osteotomies or revision joint replacement, and (3) the techniques for analyzing angular deformities of the spine. All these applications were performed with a widely available image analysis software

3D-printing techniques in a medical setting : a systematic literature review

Background: Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes. Methods: Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans. Results: 227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure. Conclusion: 3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D- printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost-effectiveness analysis