Objectives. There remains a lack of data on the reliability of methods to estimate tibial coverage achieved during total knee replacement. In order to address this gap, the intra- and interobserver reliability of a three-dimensional (3D) digital templating method was assessed with one symmetric and one asymmetric prosthesis design. Methods. A total of 120 template procedures were performed according to specific rotational and over-hang criteria by three observers at time zero and again two weeks later. Total and sub-region coverage were calculated and the reliability of the templating and measurement method was evaluated. Results. Excellent intra- and interobserver reliability was observed for total coverage, when minimal component overhang (intraclass correlation coefficient (ICC) = 0.87) or no component overhang (ICC = 0.92) was permitted, regardless of rotational restrictions. Conclusions. Measurement of tibial coverage can be reliable using the templating method described even if the rotational axis selected still has a minor influence

We aimed to determine the reliability, accuracy and the clinical role of digital templating in the pre-operative work-up for total knee replacement. Initially a sample of ten pre-operative digital radiographs were templated by four independent observers to determine the inter- and intra-observer reliability of the process. Digital templating was then performed on the radiographs of 40 consecutive patients undergoing total knee replacement by a consultant surgeon not involved with the operation, who was blinded to the size of the implant inserted. The Press Fit Condylar Sigma Knee system was used in all the patients. The size of the implant as judged by templating was then compared to that of the size used. Good inter- and intra-observer agreement was demonstrated for both femoral and tibial templating. However, the correct size of the implant was predicted in only 48% of the femoral and 55% of the tibial components. Albeit reproducible, digital templating does not currently predict the correct size of component often enough to be of clinical benefit

Digital templating in hip replacement is commonly performed with radiological markers to determine the magnification. The latter can also be determined by measuring the distance from the x-ray focal spot to the object and the distance from the x-ray focal spot to the radiological cassette or image receptor. We used post-operative radiographs of total hip replacements and hemiarthroplasties from 22 patients to calculate the magnification using both methods. The accuracy of each method was ascertained by measuring the size of the head of the implant projected on to the radiographs and comparing the result with the known size recorded in the medical records. The accuracy was found to be similar with a mean absolute measurement error of 2.6% (. sd. 1.4; 0.0% to 5.2%) for the radiological marker and 2.8% (. sd. 2.2; 0.4% to 10.1%) for the distance method (p = 0.75). The mean radiation dose for templating radiographs (pelvis and lateral of the hip) was similar when taken using a radiological marker (328 mSv . sd. 142) (n = 51) or using the distance measurement method (324 mSv . sd. 39) (n = 39) (p = 0.90). We conclude that the distance measuring method is as accurate as the radiological marker method, but may avoid some of the disadvantages such as misplacement of the marker or placement outside the radiological field. It may also be more acceptable to the patient and radiographer

Digital radiography is becoming widespread. Accurate pre-operative templating of digital images of the hip traditionally involves positioning a calibration object at its centre. This can be difficult and cause embarrassment. We have devised a method whereby a planar disc placed on the radiographic cassette accounts for the expected magnification. Initial examination of 50 pelvic CT scans showed a mean hip centre distance of 117 mm (79 to 142) above the gluteal skin. Further calculations predicted that a disc of 37.17 mm diameter, placed on the cassette, would appear identical to a 30 mm sphere placed at the level of the centre of the hip as requested by our templating software. We assessed accuracy and reproducibility by ‘reverse calibration’ of 20 radiographs taken three months after hip replacement using simultaneous sphere and disc methods, and a further 20 with a precision disc of accurate size. Even when variations in patient size were ignored, the disc proved more accurate and reliable than the sphere. The technique is reliable, robust, cost effective and acceptable to patients and radiographers. It can easily be used in any radiography department after a few simple calculations and manufacture of appropriately-sized discs

Introduction. Uncemented components necessitate accurate intraoperative assessment of size to avoid complications such as calcar fracture and subsidence whilst maintaining bone stock on the acetabular side. Potential problems can be anticipated pre-operatively with the use of a templating system. We proposed that pre-operative digital templating could accurately assess femoral and acetabular component size. Methods. Pre-operative templating data from 100 consecutive patients who received uncemented implants (Trident cup, Accolade stem) and who were operated on by the senior author were included in the study. Calibrated pelvis anterior-posterior X-rays were templated with Orthoview™ software. Demographic data, templating data (stem and cup size, femoral neck cut), operative records (actual stem and cup size, head size) and post-operative data (femoral stem alignment, radiographic leg length, acetabular cup abduction angle) were collected. Results. There were 51 males and 49 females with a mean age of 60 yrs (SD = 7.3 yrs). Seventy five percent of stems were templated to within 0.5 size and 98% to within 1 size. A total of 80% of cups were templated to within 2mm and 98% to within 4mm. 62% of head length was accurately template. Seven patients were converted from a templated 132° to a 127° femoral prosthesis neck angle. The acetabulum cup abduction angle was 45° (SD = 4.81) and stem alignment was 1.5° (SD = 1.13). The mean lower limb length discrepancy was +0.05mm (SD = 5.1 mm) post-operatively. Conclusion. Digital templating is a accurate method of assessing femoral and acetabular component sizes. This allows surgeons to foresee potential problems and also recognize an intra-operative error when a large discrepancy exists between a trial component and the templated size

Preoperative planning for Total Hip Arthroplasty has been acknowledged as a vital step to facilitate a successful outcome. Templating ascertains the dimensions and positioning of the implants, minimizing both intraoperative and postoperative complications. The purpose of this study is to compare the accuracy of digital templating to acetate templating in the preoperative planning of Total Hip Arthroplasty. Preoperative planning was performed on 40 consecutive patients (mean age = 70.5 years), undergoing Total Hip Arthroplasty. Digital templating was performed by the Hip fellow 1, using Orthoview software (Jacksonville, FL, USA) and recorded the sizes of the cup and stem for each of the 40 patients. Subsequently, the same 40 patients were templated by Hip fellow 2, with X-rays done with a lead marker of known size by the side of the femur, using, acetate templating method. Templating results were compared to the actual sizes of the implants used, as noted in operative notes. Templating scores for the acetabular cup were 40% (16/40) with digital templating and 50% (20/40) with acetate templating. The templating scores for stem were 28% (11/40) with digital templating and 90% (36/40) with acetate templating. The differences between templating and actual implant sizes were plotted in Bland–Altman plot. Acetate templating proved to be statistically, significantly more accurate than digital templating (p value= 0.0083). Our results indicate that the traditional acetate method is solid and valid to use for preoperative planning. This method is accurate and offers a more affordable option for preoperative templating. Although the templated size is one, there is a tendency to increase cup size to use bigger heads, which is the recent National Joint Registries trend. We recommend that acetate templating should be used as the default option

With the advent of digital radiology, our institution has introduced digital templating for preoperative planning of total hip arthroplasty (THA). Prior studies of the accuracy of digital templating had contradictory results. This study compares the accuracy of digital and analog templating for THA. Ninety patients were recruited. Sixty-eight patients had analog pre-operative templating while 22 patients had digital templating. A retrospective review of medical records obtained the sizes of hip implants inserted during THA and patient demographics. The templated hip sizes were compared with the actual hip implants inserted. Accuracies of both templating methods were compared in four outcomes: prediction of acetabular cup size, prediction of femoral stem size, prediction of femoral offset and prediction of femoral neck length. Digital templating was more accurate than analog templating in predicting acetabular cup size, femoral stem size and femoral offset. Analog templating was more accurate in predicting femoral neck length. However, only the comparison of femoral offset achieved statistical significance (p-value = 0.049). After stratifying the data by BMI, digital templating was more accurate than analog templating in predicting acetabular cup and femoral stem sizes for patients with high BMI. For patients with BMI = 25-30, accuracy of digital templating was 100.0% for cup and 80.0% for stem while accuracy of analog templating was 74.1% for cup and 74.1% for stem. For patients with BMI > 30, accuracy of digital templating was 84.6% for cup and 69.2% for stem while that of analog templating was 75.0% for cup and 66.7% for stem. Digital templating outperformed analog templating in all the outcomes except femoral neck length. In addition, digital templating was significantly more accurate in predicting femoral offset. This study showed that digital templating has the potential to reduce errors in pre-operative planning for THA

Introduction: Preoperative planning plays an important role in any surgical procedure and total hip replacement (THR) is no exception. Templating of radiographs allows preoperative assessment of the correct size of implant to be used, lowers the risk of periprosthetic fracture, helps restore femoral offset and leg length, facilitates the optimisation of alignment and ensures the correct implants sizes are available. With the wide scale use of Picture Archiving and Communication Systems (PACS) in the National Health Service (NHS), the potential exists for faster and more accurate templating of THRs. Aim: In performing this study, we assessed whether there is adequate provision of the current NHS PACS to allow optimal digital templating for THRs. We also made comparison between the availability and overall ease of conventional versus digital templating. Methods: Data was collected using a telephone questionnaire requesting information from the on-call orthopaedic Specialist Registrar (SpR) in 28 Greater London and surrounding area NHS Hospitals. Data on the availability of PACS and the ability to template using hard-copy or digital templating was collected and analysed. Results: PACS were used in all 28 (100%) hospitals that were contacted. None performed conventional templating regularly and only 8 (28.6%) admitted to occasional templating. The predominant reason for this was difficulty in obtaining hard copies of x-rays in 12 (42.9%) hospitals, as well as lack of availability acetate templates, with 13 (46.4%) claiming that this was the case. Digital templating software was available in 14 (50%) hospitals. Despite this, none of them performed digital templating regularly. In the 50% that did have digital templating, this was not routinely done for the following reasons:. only 3 (10.7%) allowed easy access to the software to the SpRs. only one SpR received formal training on how to use the system. only one hospital regularly used Methods: to accurately allow the software to assess magnification for accurate sizing (e.g. sizing balls). Discussion: Digital PACS systems have made great improvement in the access of radiographs in the NHS. With regards to orthopaedic practice, however, we have shown that the benefit of digital templating is being overlooked within the NHS

We aimed to determine the reliability, accuracy and consequently the clinical role of digital templating in the pre-operative work up for total knee arthroplasty patients. With the increasing use of digital radiology images, analogue templating may soon be defunct. Digital templating is a more recent development and its role is yet to be determined. Ten pre-operative digital radiographs were templated by four independent observers. Inter-observer and intra-observer reliability was assessed using the kappa measure of concordance. Subsequently, 40 consecutive total knee arthroplasty patients underwent pre-operative digital templating. This was a blinded process by a consultant surgeon not involved with the operation. Each patient underwent TKR using the PFC Sigma System sized intra-operatively, without the operating surgeon having knowledge of the pre-operative templating result. Comparison was made between the pre-operative digital templates and the blinded intra-operative sizing. For both the femoral and tibial templating there was good to very good inter- and intra-observer agreement. For the femoral component the templating was correct in 47.5% (± 1 size difference 97.5%). The tibial templating was correct in 55% (± 1 size difference 100%). The inter- and intra-observer reliability of digital templating process has been shown to be acceptable but the correlation between digital templating and the actual size implanted is poor. Our series shows a similar accuracy to the published data on analogue templating for the same implant. Like analogue templating, its clinical role remains uncertain and its poor correlation to the actual implant sizes limits its usefulness

The aim of our study was to determine the usefulness of preoperative digital templating of cementless total hip arthroplasty (THA). 60 consecutive cementless THA (synergy stem & reflection cup) were templated digitally by two senior hip arthroplasty fellows (GM, YG) independently. A metallic marker ball of known diameter was used in all images to help scale for magnification. A blinded observer then collated information on the actual implant sizes, size of head component, offset, and level of neck cut intraoperatively. This was used to statistically analyse the correlation (Interclass correlation coefficient) between the digitally templated implant sizes and actual implant sizes used and the reliability of digital templating. A high rate of coincidence between digitally templated estimates and actual implant sizes was noted for both groups of templates. A high intraclass correlation coefficient (ICC) for the acetabular cup, stem and head were noted (ICC of 0.825, 0.794, and 0.884 respectively). Moderate agreement was noted for neck cut (ICC of 0.567) and leg length (ICC of 0.612). In conclusion, digital templating can reliably estimate implant sizes in cementless total hip arthroplasty. Valuable information on neck cut and leg length can be obtained by preoperative templating

Digital radiographs have taken over from conventional radiographs in most of the hospitals in New Zealand. This has created a challenge with respect to templating and pre-operative planning of total hip replacement surgeries. Digital templating has not, until recently, been available in our hospitals. Recently, a digital templating system (Cedara) has become available and has been installed and used at Middlemore Hospital and at Manukau Surgical Centre. This system allows computerised templating of digital radiographs. The aim of this study was to assess the accuracy of digital templating and to compare this method to the “compromised” conventional templating that has been performed at Middlemore hospital for the last 10 years. In order to correct for magnification a fiducial stand has been created. This is a plastic stand and a pole with a movable 36mm metal ball. The ball is placed at the level of the greater trochanter and the stand is then placed between the patients legs. A standard templating “AP pelvis for hips” radiograph is then taken with the limbs internally rotated, such that the patellae are facing anteriorly. A traditional hard film was then created from this image for traditional acetate templating. Digital templating, with the Cedara system, was performed on the digital images after calibrating the image size using the fiducial image of known size. The results of the two methods were tabulated. The operation record was read and the component size and type was tabulated. The postoperative radiographs were assessed and the component positioning was evaluated and compared with the conventional and digital templates. A critical assessment of component size, with respect to under sizing and over sizing, was also performed on the postoperative radiographs and this was correlated with the digital and conventional templates. This templating, and the evaluation of the postoperative radiographs, was performed by the authors of this paper (a consultant surgeon and a registrar). The accuracy of the two templating methods was assessed by comparison with the post operative radiographs and also with the aid of the knowledge of the actual components which were used at the time of surgery. The templating images and radiographs of 100 patients were evaluated in the above stated manner and the results were analysed. The results from this analysis will be presented

Background. Digital templating is a critical part of preoperative planning for total hip arthroplasty (THA) that is increasingly used by orthopaedic surgeons as part of their preoperative planning process. Digital templating has been used as a method of reducing hospital costs by eliminating the need for acetate films and providing an accurate method of preoperative planning. Pre-operative templating can help anticipate and predict appropriate component sizes to help avoid postoperative leg length discrepancy, failure to restore offset, femoral fracture, and instability. A preoperative plan using digital radiographs for surgical templating for component size can improve intraoperative accuracy and precision. While templating on conventional and digital radiographs is reliable and accurate, the accuracy of templating on digital images acquired with a novel biplanar imaging system (EOS Imaging Inc, Cambridge, MA, USA) remains unknown. EOS imaging captures whole body images of a standing patient without stitching or vertical distortion, less magnification error and exposes patients to less radiation than a pelvis AP radiograph. Therefore, the purpose of this study was to compare EOS imaging and conventional anteroposterior (AP) xrays for preoperative digital templating for THA, and compare the results to the implant sizes used intraoperatively. Methods. Forty primary unilateral THA patients had preoperative supine AP xrays and standing EOS imaging. The mean age for patients was 61 ± 8 years, the mean body mass index 29 ± 6 kg/m. 2. and 21 patients were female. All patients underwent a THA with the same THA system (R3 Acetabular System and Synergy Cementless Stem, Smith & Nephew, TN, USA) by a single surgeon. Two blinded observers preoperatively templated using both AP xray and EOS imaging for each patient to predict acetabular size, femoral component size, and stem offset. All templating was performed by two observers with standard software (Ortho Toolbox, Sectra AB, Linköping, Sweden) [Figure 1] one week prior to surgery, and were compared using the Cronbach's alpha (∝) coefficient of reliability. The accuracy of templating was reported as the average percent agreement between the implanted size and the templated size for each component. Results. For templating acetabular component size, the exact size was predicted for 48% using AP xrays and 70% using EOS imaging, and within 1 size for 88% using xrays and 98% using EOS imaging. For templating femoral component size, the exact size was predicted exactly for 33% using AP xrays and 60% using EOS imaging, and within 1 size for 85% using xrays and 98% using EOS imaging (Figure 2). Interobserver agreement was excellent for acetabular components (Cronbach's α = 0.94) and femoral components (Cronbach's α = 0.96) using EOS imaging. Conclusions. This study demonstrates that preoperative digital templating for THA using EOS imaging is accurate, with excellent interobserver agreement. EOS imaging has less magnification error, which may partially explain the accuracy of our templating method

Introduction. Aim of this study is to assess any differences in digital templanting accuracy of a modular short femoral stems implanted with 2 different appoaches (direct anterior and posterolateral). Material and Methods. From December 2012 to Jenaury 2014 100 patient undergoing to a THA using the same implant with a short femoral modular stem were prospectively included in the study and divided in 2 groups according to the surgical approach. All the patients underwent to the same preoperative radiological protocol and the digital templating. The digital templating results were compared with the truly inserted implant size and a statistical analysis was carried on. Results. For the cup the mean percentage of agreement (±2 size) was 90.0 % in Anterior approach-group and 89.6 % in the the posterolateral approach group. For the mean percentage of agreement (± 2 size) was 88.0 % in and 89.1 % respectively. Likewise there was a statistical significant better accuracy in the modular femoral neck accuracy in the anterior approach (±2 size) and a statistical significant higher percentage of modular femoral neck with an increased antiversion in the posterolateral approach. Discussion. In our experience digital templating in short modular femoral stem seems to be less accurate for the posterior-lateral approach in term of both femoral neck length and antiversion. A possible explanation may be not a technical error but just a surgeon behavior to overcorrect the templating to prevent dislocation potentially more common using a postero-lateral approach

Introduction. When total knee arthroplasty (TKA) or unicompartmental knee arthroplasty (UKA) was indicated for the patient, it is important to perform the exact preoperative planning. Conventionally we created the plan based on the Xp films and transparent acetate sheets. Recntly, the digital radiographs and templating systems were introduced in hospitals and utilized for the preoperative planning. The purpose of this study is to investigate the accuracy of the digital templating by comparing the size of the implants between those chosen by the planning and those actually selected during the operation. Materials and methods. We investigated the plans of 715 knees with TKAs and 238 knees with UKAs between 2010 and 2014. There were 89 men and 438 women with average age of 72.1. There were 867 osteoarthritis, 46 rheumatoid arthritis, 39 osteonecrosis and 1 revision TKA. We created the preoperative planning using Electronic Picture and Communication system (PACS) and templating system (Advanced Case Plan 2.2 / Stryker). [Fig. 1] During the operation we have checked the actual femoral and tibial sizes of the implants, and compared them with preoperative plannings. Results. The exact matching of the sizes of the implants between the planning and the operation with TKAs were 59.4% for the femoral components, 52.7% for the tibial components and 32.4% for both components. [Fig. 2] While those figures with UKAs were 88.7%, 67.6% and 63.0% respectively. [Fig. 3] The matching within 1 size difference of the size of the implants between the planning and the operation were 92.4% with TKAs and 95.8% with UKAs. Discussion. Our study suggested that the digital templating of the TKAs and UKAs had satisfactory accuracy to use as preoperative planning for the operation. The accuracy was better in femur than that of tibia. The difference of the accuracy indicate the probable presence of the hyperplasia of the medial tibial condyle that we cut off to get good ligamtnt balancing. The accuracy of the UKAs was better than that of TKAs. During UKAs, we initially chose the predicted size of the devise and cut the bone, and then finally select the size of the implant. While during TKAs, we measure the size of the bone and then cut the bone. This difference of the operative procedure may result in the higher accuracy of UKAs. We conclude that digital templating for preoperative planning of TKAs and UKAs had satisfactory accuracy

Abstract. Introduction. Osteotomy is a recognised surgical option for the management of unicompartmental knee osteoarthritis. The effectiveness of the surgery is correlated with the accuracy of correction obtained. Overcorrection can potentially lead to excess load through the healthy cartilage resulting in accelerated wear and early failure of surgery. Despite this past studies report this accuracy to be as low as 20% in achieving planned corrections. Aim. Assess the effectiveness of adopting modern osteotomy techniques in improving surgical accuracy. Methodology. A prospective cohort study. Patients were identified who had undergone osteotomy surgery for unicompartmental knee OA using a standardised technique. The surgical techniques adopted to ensure accuracy included digital templating software (Orthoview), Precision saw(Stryker), bone wedge allograft and plate osteosynthesis (Tomofix). Pre and post operative analysis of standardised long leg X-rays was performed and the intended (I) and achieved(A) corrections were calculated. Results. A total of 94 (35F/59M) patients with a mean age of 52 years were identified who fulfilled the inclusion criteria for the study. 62 patients were treated with a tibial osteotomy, 21 with femoral and 11 with a double level osteotomy. Using a 10% acceptable range (AR) for error, in 89% of cases (84 of 94) the target Mikulicz point was achieved. Potential risk factors for overcorrection included female sex and osteotomy type, with a higher incidence of over correction observed with double level osteotomies (27%). Conclusion. This study demonstrates that meticulous digital software planning and surgical technique ensures accurate surgical correction in periarticular knee osteotomy surgery

Digital radiography has replaced traditional radiography in many hospitals yet little is known regarding the accuracy of this new technology in THA templating. Our study analyzed the reproducibility and reliability of computer templating in primary uncemented THA as compared to standard on-lay templating techniques with hardcopy radiographs from a digital source. In December 2004 our hospital converted from standard hardcopy radiography to digital radiography. Patients undergoing THA had preoperative digital radiographs taken which included an AP pelvis with a 50mm magnification marker place in the groin, AP hip, and a cross-table lateral. Forty patients were selected that met our inclusion criteria to begin the templating process, including adequate placement of the magnification marker and optimal hip implant positioning on the postoperative films. Cases that did not have a marker, had significant deformity or mal-positioned implants were excluded. Hardcopies of digitised radiographs were printed and a traditional templating technique using 120% magnified on-lay transparent templates was performed (Capello, 1984). Digital templating was performed using OrthoView Software (Bono, 2004). Templating was conducted by two staff surgeons and one resident. Intra-observer and inter-observer effects were calculated using an Intraclass Correlation Coefficient (ICC). Digital templating showed good inter-observer and intra-oberserver reliability with ICC values > 0.7. Using computer templating, the femoral stem was accurately predicted to within one size in 85% of the cases, and the acetabular cup was accurately predicted to within one size in 80% of the cases.Using on-lay templating, the femoral stem was accurately predicted to within one size in 85% of the cases, and the acetabular cup was accurately predicted to within one size in 60% of the cases. There was a significant difference between the accuracy of acetabular cup templating between techniques, likely as a result of the ability of computer templating to adjust for magnification error. Computer templating was able to accurately predict postoperative leg-length discrepancy, abduction angle and horizontal offset. Overall, computer templating was found to be a reproducible and reliable technique for uncemented THA. Problems and lessons learned in the implementation of a digital templating system will be discussed

[Introduction]. Short tapered wedge-shaped cementless (TW) stems have been widely used for several years. The concept of fixation of TW stem is wedge-fit fixation in the proximal metaphysis. Developmental dysplasia of the hip (DDH) has anatomical abnormality, such as excessive femoral anteversion, short femoral neck length, narrow femoral cavity, or proximal-distal mismatching of the femoral canal. Therefore, Mismatching between stem and bone might be occurred in DDH. We evaluated intramedullary matching of short TW stem for DDH by three dimensional (3D) digital template in order to clarify whether mismatching between stem and bone is seen in DDH implanted short TW stem. [Materials and Methods]. One hundred hips (92 patients) with DDH were performed preoperative simulation for total hip arthroplasty by 3D digital template system (ZedHip: Lexi, Tokyo, Japan). The average age was 63.5 years old. There were 12 males and 80 females. The average bone mass index was 21.5 kg/m. 2. Femoral canal shape was normal in 71, champagne-flute in 16 and stovepipe in 13 hips. Bone quality was classified into type A in 23, type B in 74 and type C in 3 hips. Preoperative computed tomography data were used for 3D digital template and reconstructed to 3D femoral model. Short TW stem (Taperloc Complete Microplasty: Biomet, Warsaw, IN) model constructed from computer-assisted design was matched to the reconstructed femoral model. Short TW stem model was in principle implanted according to the femoral neck anteversion with neutral alignment (varus and valgus < 2 degrees, flexion and extension < 2 degrees) at the coronal and sagittal plane of the femur. Stem size was determined in order to obtain the largest intramedullary matching at the coronal plane. Area of stem fitting with the cortical bone was investigated at 10 mm intervals above and below of mid minor trochanter. Intramedullary matching pattern was classified into proximal mediolateral metaphyseal fit, proximal flare fit and diaphyseal fit at multiple reconstructed planes of the 3D femoral model according to stem fitting area. [Results]. Ninety-three percent of stem could be implanted with neutral alignment at the coronal plane, and 86 percent at the sagittal plane. The average stem anteversion was 31.4 degrees. Over 70 percent of stem could be fit with the medial and lateral cortical bone at 10 mm above and below of mid minor trochanter. Intramedullary matching pattern was proximal mediolateral metaphyseal fit in 49%, proximal flare fit in 44% and diaphyseal fit in 7%. [Discussion and Conclusion]. Early migration or failure of osteointegration of TW stem was recently published. Diaphyseal fixation or mismatching between stem and bone is considered as risk factors of early failure of TW stem. In this study, proximal metaphyseal fit, such as mediolateral metaphyseal fit or flare fit, could be achieved in 93% of DDH patients. Mismatching between stem and bone, such as diaphyseal fit, was observed only in 7% of DDH. Short TW stem is good choice for DDH in order to avoid of diaphyseal fixation followed by early migration of stem and decreased osteointegration

We have investigated the accuracy of the templating of digital radiographs in planning total hip replacement using two common object-based calibration methods with the ball placed laterally (method 1) or medially (method 2) and compared them with two non-object-based methods. The latter comprised the application of a fixed magnification of 121% (method 3) and calculation of magnification based on the object-film-distance (method 4). We studied the post-operative radiographs of 57 patients (19 men, 38 women, mean age 73 years (53 to 89)) using the measured diameter of the prosthetic femoral head and comparing it with the true value. Both object-based methods (1 and 2) produced large errors (mean/maximum: 2.55%/17.4% and 2.04%/6.46%, respectively). Method 3 applying a fixed magnification and method 4 (object-film-distance) produced smaller errors (mean/maximum 1.42%/5.22% and 1.57%/4.24%, respectively; p < 0.01). The latter results were clinically relevant and acceptable when planning was allowed to within one implant size. Object-based calibration (methods 1 and 2) has fundamental problems with the correct placement of the calibration ball. The accuracy of the fixed magnification (method 3) matched that of object-film-distance (method 4) and was the most reliable and efficient calibration method in digital templating

Surgeon’s ability to anticipate the implant size requirements for total knee replacements is important to the success of the procedure. Previously, this has been inconsistently accomplished using plain radiographs. The purpose of this study is to assess the accuracy of digital templating software in predicting the size requirements of the femoral and tibial implants in total knee replacements. Thirty consecutive PFC (DePuy) total knee replacements were templated preoperatively using digital templating software (TraumaCad, Orthocrat Ltd). The knees were templated by two surgeons working independently using standardised digital AP and lateral radiographs. All films were magnification-calibrated using markers of known size. Postoperatively, the predicted implant size was compared to the actual components selected at the time of surgery. The size of the femoral prosthesis was accurately selected on the AP view in 53.5% and on the lateral in 66% of cases. The size of the tibial implant was correctly selected on the AP view in 65.5% and on the lateral in 70.5% of cases. The tibial prosthesis was always templated within one size. The femoral prosthesis was predicted within two sizes (93% on AP + 98% on lateral +/− 1 size). There was no correlation with failure of the software to recognise the metal marker and inadequate lateral x-rays. The lateral x-ray was found to be more reliable than the AP on predicting both the femoral and tibial implants. The tibia was more accurately templated than the femur on average. There was good inter-observer and intra-observer reliability for both prostheses (0.75 – 0.85). Discrepancies in templating may have been due to inaccuracies in placement of the metal marker at the time of x-raying or due to fixed flexion deformities, which may have affected the magnification of the x-ray. Overall, templating using digital software was marginally superior to the standard acetate method

Introduction: The aim of the study was to investigate the reproducibility and accuracy of templating total hip arthroplasty with on-screen digital radiographs using three commercially available software packages, and compare the results to templating on-screen using acetates. Method: In twenty patients undergoing hybrid total hip arthroplasty, pre-operative templating for acetabular size, femoral offset and stem size were performed by three independent observers using on-screen digital radiographs by three different techniques. The magnification of the on-screen images were adjusted appropriately by using a metal coin marker of known size attached to the patient at time of acquiring the radiographs. These images were used to template for total hip arthroplasty using three commercially available digital templating software packages (Orthoview™ Workstation, Southampton, UK, Ferrania LifeWeb TraumaCad™, Berkshire, UK and mdesk™ software suite, RSA Biomedical, Sweden). The templated results were compared with the component sizes subsequently implanted and to templating on-screen using acetates. Intra- and inter-observer reproducibility were assessed using the Intraclass Correlation Coefficient (ICC). Results: Intra-observer reproducibility was good for the three software systems with almost all ICC values > 0.70. Inter-observer reproducibility was less consistent, which may reflect familiarity and may improve with a “learning curve”. All three software systems tended to slightly undersize the acetabular size. Discussion: For both reproducibility and accuracy, all the three commercial systems were comparable with templating using the acetate template method. Digital templating using software packages is an acceptable method of templating. Templating software packages are certainly an attractive proposition but until installation & maintenance costs are reduced, “traditional” templating with acetates remains the most effective option