Digital Templating Research Articles

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.

AB221. 154. Accuracy of positioning of scaling ball in pre-operative imaging for total hip arthroplasty

Background: Accurate preoperative planning improves surgical outcomes. Positioning of an external calibrator marker (ECM) used in digital templating can be complicated by many factors. Previous papers have evaluated the accuracy of different types of markers and X-ray quality, this audit aims to evaluate how the variability of the SB position effects templating.

The accuracy of digital templating in uncemented total hip arthroplasty

IntroductionPreoperative planning is an essential part of total hip arthroplasty (THA). It facilitates the surgical procedure, helps to provide the correct implant size and aims at restoring biomechanical conditions. In recent times, surgeons rely more and more on digital templating techniques. Although the conversion to picture archiving and communication system had many positive effects, there are still problems that have to be taken into consideration.ObjectivesThe core objective was to evaluate the impact of the planners’ experience on the accuracy of predicting component size in digital preoperative templating of THA. In addition, the influence of overweight and obesity (according to WHO-criteria), patient’s sex and component design on the accuracy of preoperative planning have been analysed.Materials and methodsThe retrospective study included 632 consecutive patients who had primary uncemented THA. Digital templating was done using “syngo—EndoMap” software by Siemens Medical Solutions AG. Mann–Whitney U test and Kruskal–Wallis test have been used for statistical analysis.The accuracy of predicting component size has been evaluated by comparing preoperative planned sizes with implanted sizes as documented by the surgeons. The planner’s experience was tested by comparing the reliability of preoperative planning done by senior surgeons or residents. The influence of BMI on predicting component size has been tested by comparing the accuracy of digital templating between different groups of BMI according to WHO-criteria. The same procedure has been done for evaluating the impact of patient´s sex and component design.ResultsThe implant size was predicted exactly in 42% for the femoral and in 37% for the acetabular component. 87% of the femoral components and 78% of the acetabular cups were accurate within one size. Digital templating of femoral implant size was significantly more reliable when done by a senior surgeon. No difference was found for the acetabular component sizes. The BMI also had an impact on estimating the correct femoral implant size. In overweight patients, planning was significantly more inaccurate than normal weight people. Differences were seen in obese patients. However, these were not significant. Accuracy of acetabular components was not affected. The design of the prostheses and the patient’s sex had no influence on predicting component size.ConclusionsInexperience and overweight are factors that correlate with inaccuracy of preoperative digital templating in femoral components, whereas acetabular components seem to be independent of these factors.

Digital templating of rotating hinge revision and primary total knee arthroplasty.

Preoperative digital templating in total knee arthroplastiy (TKA) is useful in predicting implant size, the level of bone resections and the need for special implants. This study should evaluate the templating of a rotating hinge prosthesis and the realization of the preoperative plan. Two observers with different experience levels templated 40 cases which received TKA and R-TKA using digital planning on standard preoperative x-rays. The examiners templated all cases independently and were blinded to the component sizes used intraoperatively. The kappa coefficient and Pearson coefficient were determined. The accuracy in predicting the correct implant size in revision TKA varied from 67,9% to 82,1% depending on the training level of the observer. The two observers show moderate and substantial correlation. The coefficient indicates a substantial agreement in between the two observers in templating revision TKA. The accuracy depends on the experience of the observer. In the cases were the templating was incorrect, the prosthesis was implanted smaller than the preoperative plan. With this knowledge very good results can be made with this prosthesis.

Ignoring Digital Templating Leads to Prosthetic Overhang in Total Knee Replacement

Abstract Published studies on the accuracy of digital templating in total knee replacement (TKR) have employed standard knee, but not hip-to-ankle radiographs. A retrospective study was conducted in our hospital on patients undergoing TKR due to osteoarthritis in a period of six consecutive months. Templating was performed using a calibrating 25 mm metallic ball and Agfa Orthopaedic Tools software by a surgeon not involved with the operation. The surgeon performing the templating was blinded to the size of the implants inserted. Postoperative knee anteroposterior and lateral radiographs were then checked for the presence of prosthetic overhang of ≥ 3 mm. In total, 132 Caucasian adults were included in the study. Femoral overhang occurred in 33%, whereas tibial overhang in only 6% of cases. The exclusion of prosthetic overhang cases significantly improved the accuracy of size detection; exact match for femur increased from 55% to 69%, and for tibia from 70% to 73%. All implants were predicted to within one size in all cases. Digital templating using a calibrating 25 mm metallic ball, Agfa Orthopaedic Tools software and hip-to-ankle and knee lateral radiographs is an accurate method of predicting the knee implant to within one size. Ignoring this procedure leads to prosthetic overhang.

Digital templating without a calibration marker is accurate at predicting implant size for hip hemiarthroplasty.

This study aims to assess the accuracy of digital templating for hip hemiarthroplasty using radiographs without calibration. Two independent, blinded observers retrospectively utilised digital software to template 50 consecutive patients who had hip hemiarthroplasty. The templated parameters (head size, offset and stem size) derived from pre-operative radiographs were compared to the actual prosthetic sizes used intra-operatively. Inter and intra-observer variabilities were calculated. Both observers correctly templated the offset and head size (± 2mm) used in 90% (n = 45) of cases. The femoral stem size (± 1 size) was correctly predicted by templating in over 84% of the cases (n = 42). Inter-observer agreement was excellent for femoral head size with an intra-class correlation coefficients (ICC) of 0.94, substantial for offset (k = 0.7) but only fair for stem size (k = 0.27). ICC values comparing the actual prostheses inserted with the template values were excellent for head size (ICC = 0.96), substantial to near perfect for offset (k = 0.78, 0.85) and fair to moderate (k = 0.24, 0.45) for stem size. Digital templating of radiographs without calibration can be used to accurately and reliably predict femoral head size and offset at a set magnification of 120%. Femoral stem size, however, is more difficult to template adequately on pre-operative radiographs without calibration.

Influence of calibration on digital templating of hip arthroplasty.

Digital templating for total joint replacement is the current standard. For image calibration, external calibration markers (ECM) are used. However, there are concerns regarding the precision of the method. This study aimed to identify the direct influence of calibration errors on digital templating. A retrospective analysis of 100 post-operative radiographs with unilateral total hip arthroplasty was performed. The magnification factor of the ECM and of the internal prosthetic femoral head (ICM) as a reference value was calculated for each radiograph. Two blinded observers performed templating of the contralateral hip using a randomized list for all radiographs and both markers. The component size templated by the ECM magnification was compared to the reference by the ICM magnification. Mean magnification factors of ICM and ECM differed significantly (p = 0.006). The absolute difference was 5.2% (range 0.0-23.3%, SD 4.8%). Templating of the acetabular or the femoral component showed no significant differences (p = 0.120, p = 0.599). Differences of more than one size were found in 26% of the acetabular components and 14% of the femoral components and differences over two sizes in 10% respectively 3%. Correlation coefficients for magnification error and size differences of acetabular components were - 0.645 (p < 0.001) and for the femoral component - 0.607 (p < 0.001). The calibration error of external calibration markers in digital templating for hip replacement influences component sizes significantly. Thus, correct positioning of ECM is of utmost importance.

Reliability and efficiency of three methods of calculating migration percentage on radiographs for hip surveillance in children with cerebral palsy.

PurposeHip surveillance programmes for children with cerebral palsy (CP) utilize the migration percentage (MP) measurement to initiate referrals and recommend treatment. This study assesses the reliability and efficiency of three methods of MP measurement on anteroposterior (AP) pelvis radiographs.MethodsA total of 20 AP pelvis radiographs (40 hips) of children with CP were measured by three raters on two occasions using three methods: digital measurement (DM) on a Picture Archiving and Communication System monitor, computer-aided measurement (CA) using a digital templating tool and mobile device application measurement (MA) using a freely available MP measurement tool. For each method, the time required to complete the MP measurement of both hips on each AP pelvis radiograph was measured. Intra-class correlation coefficient (ICC) was used to determine reliability, and analysis of variance was used to compare groups.ResultsAll three methods of determining MP showed excellent inter-rater and intra-rater reliability (ICC 0.976 to 0.989). The mean absolute difference in MP measurement was not significant between trials for a single rater (DM 2.8%, CA 1.9%, MA 2.2%) or between raters (DM 3.6%, CA 2.9%, MA 3.6%). The mean time to complete MP measurement was significantly different between methods, with DM = 151 seconds, CA = 73 seconds and MA = 80 seconds.ConclusionAll three MP measurement methods were highly reliable with clinically acceptable measurement error. The time required to measure a hip surveillance radiograph can be reduced by approximately 50% by utilizing a computer-based or mobile application-based MP measurement tool.Level of Evidence III

The 3-dot circle: A reliable method for safe and efficient digital templating of the acetabular component

BackgroundTemplating for preoperative planning of joint arthroplasty has followed the evolution of digital templating software. ObjectiveThis study aims to provide a safe, reliable and reproducible method for prediction of acetabular component size based on measurement of the radiographic femoral head diameter, with the aid of templating software. MethodsA defined methodology for femoral head measurement was applied to 97 consecutive, calibrated digital pelvic radiographs. Based on radiographic femoral head diameter, the minimum acetabular shell diameter was calculated and then compared to the size of the implanted acetabular shells. ResultsThis method predicted safe minimum acetabular component size with an accuracy of 95.9% with a high inter-observer reliability of 97.6%. ConclusionsThis study presents a simple, reproducible and accurate method for templating of the minimum safest acetabular component diameter.

Templating in uncemented THA. On accuracy and postoperative leg length discrepancy

PurposeThis study examines the accuracy of digital templating in uncemented total hip arthroplasty (THA), i.e., whether the templated components where actually inserted during surgery. The surgical outcome was evaluated on the basis of limb length equality. MethodsWe retrospectively examined digital x-rays of 41 patients scheduled for uncemented THA. These were templated using templating software. The template was compared to the surgical choice of implant registered in the patients’ journal. Postoperative x-rays were evaluated for limb length equality. The data underwent statistical analysis to assess accuracy. ResultsThe acetabular component was templated accurately in 7.3%, while 41% was within +/− 1 component size difference, and 73% was within +/−2 size differences. The femoral stem was templated accurately in 34%, while 76% was within +/− 1 component size difference, and 90% was within +/−2 size differences. The neck length was templated accurately in 29%, while 88% was within +/−1 component size difference, and 100% was within +/−2 size differences.Fifty four percent of patients experienced radiologic equalization within +/− 5 mm, and 85% within 10 mm. Fifteen percent had leg length discrepancy of more than 10 mm postoperatively. There was no systematic tendency to overestimate or underestimate leg length peroperatively. ConclusionsWe find that the accuracy of digital templating in uncemented THA is acceptable for the femoral stem, but somewhat inferior for the acetabular shell and poor for neck length. Templating is a useful tool in preoperative planning, but cannot be regarded as a blueprint for the operative choice.

Radiologic Analysis of C2 to Predict Safe Placement of Pedicle Screws.

Preoperative assessment of C2 pedicle morphology is critical to safe pedicle screw placement. To avoid iatrogenic injury, complex digital templating software has been introduced; however, this technology may not be available in many centers. We report a technique for preoperative assessment of C2 pedicle screw placement safety based upon 2-dimensional sagittal computed tomography (CT) scan images and verify its utility in clinical practice. A total of 46 consecutive patients underwent cervical spine CT scans between 2005 and 2011. The C2 pedicle morphology was assessed on sagittal CT imaging by 5 independent reviewers to determine the feasibility and risk associated with pedicle screw placement. Thirty consecutive patients underwent C2 pedicle screw placement and were followed clinically for a minimum of 2 years. The ability to place a screw was noted, and accuracy of screw placement was assessed postoperatively by CT scan. The CT scan analysis demonstrated that 11% (5/46) of patients had sufficient pedicle size bilaterally to allow safe placement of long pedicle screws with a low risk of vertebral artery injury, whereas 15% (7/46) were considered a high risk bilaterally. Screw placement was deemed low risk in 28%, moderate risk in 38%, and high risk in 34%. Excellent intraobserver reliability and good interobserver reliability was observed. Clinically, 18 of 20 (90%) low-risk and 21 of 24 (88%) moderate-risk pedicle screws were placed safely versus 5 of 16 (31%) high-risk pedicle screws (P < .001). Using the described technique for evaluating the C2 pedicle via sagittal CT scan images allows for safe and reliable pedicle screw placement without relying upon complex digital templating software, which may have limited availability. II. This study aids in the surgical decision-making behind the placement of C2 pedicle screws using CT scans without reliance upon complex digital templating software.

A New Preoperative Planning Technique Can Reduce Radiation Exposure During the Performance of Medial Opening-Wedge High Tibial Osteotomy.

Medial opening-wedge high tibial osteotomy (HTO) is one of the most common and effective HTO techniques, in which the proximal tibia is cut medially, leaving an intact lateral hinge of bone that can be opened to a variable amount for the desired correction, but the technical complications of lateral cortex fracture and intra-articular fracture are well described. The lateral bone hinge for medial opening-wedge HTO is crucial. If the hinge is too small, the tibia can fracture and become unstable, requiring further fixation. If the hinge is too large, the osteotomy can propagate into the joint as an intra-articular fracture when opening the osteotomy. We propose a new technique that utilizes digital preoperative templating to improve the accuracy of the cut. Preoperative digital templating may allow the surgeon to reproducibly obtain a lateral bone hinge of 10mm, while also reducing radiation exposure relative to the traditional fluoroscopically assisted technique. Ten cadaver extremities from five cadavers were matched into pairs and randomized into two groups: those with and without preoperative templating. The templating protocol measures the distance between two points on the medial and lateral cortices, and 20mm is subtracted to determine the depth of the saw cut (10mm for the hinge and another 10mm because the proximal tibia is oval in shape). The control method was done by making the cut using fluoroscopy with tactile feedback. Postoperative computed tomography scans were obtained of all legs to measure the width of the lateral bone hinge. Intraoperative fluoroscopy used during both techniques and the numbers of fluoroscopy shots were recorded. We found neither the treatment group with preoperative planning nor the control group with the conventional technique had bone hinge widths that were different from the ideal 10mm. The average hinge widths for the treatment and control groups were 11.2 and 11.5mm, respectively. However, the treatment group was exposed to significantly less intraoperative fluoroscopy during the osteotomy cut. The average total number of fluoroscopy shots was 2.2 in the treatment group versus 6.3 for the control group. This new preoperative planning technique achieves similar accuracy of the lateral bone hinge when compared to current methods but exposes the patient, surgeon, and staff to significantly less intraoperative radiation.

Scaling Marker Position Determines the Accuracy of Digital Templating for Total Hip Arthroplasty.

Digital templating systems foster patient-specific measurements for preoperative planning. We aim (1) to verify the accuracy of a templating system, (2) to describe the effects of scaling marker position on the accuracy of digital templating of the hip, and (3) to provide a practical guide for scaling marker position using patient body mass index (BMI). A scaling sphere was placed in five positions along the anterior-posterior axis of an acetabular implant and pelvis phantom, and x-rays were obtained. Each radiograph was templated for the acetabular component and recorded. A retrospective review identified CT scans of preoperative hip arthroplasty cases. The center of the greater trochanter was calculated from these CT scans as the percent distance from the anterior thigh and recorded with the patient's BMI. By centering the scaling sphere on the acetabular component, an accurate cup size was achieved. A difference of 3.5cm in sphere placement resulted in a full cup size magnification error. Positioning the scaling sphere at the level of the pubic symphysis resulted in a difference of four cup sizes. This patient population had an average BMI of 28.72kg/m2 (standard deviation 6.26kg/m2) and an average position of the center of the greater trochanter of 51% (standard deviation of 6%) from the anterior surface of thigh. Digital templating relies on scaling marker position to accurately estimate implant size. Based on the findings in this study, scaling markers for hip imaging should be placed laterally, mid-thigh in the anterior-posterior direction for patients with a BMI between 25 and 40kg/m2. If abnormal hip anatomy or extremes of BMI are discovered, then scaling sphere positioning should be optimized on a case-by-case basis. Digital templating systems for total hip arthroplasty must use precisely placed scaling markers at the level of the hip joint to allow for accurate implant size estimation.

Templating digital radiographs using acetate templates in Total Hip Arthroplasty

Introduction & objectivePreoperative templating in Total Hip Arthroplasty (THA) has traditionally been done with conventional radiographs. With conventional films being replaced by digital films, it has become difficult for surgeons to template the hip preoperatively, as digital templating involves special software, carries an additional cost and is not freely available. We describe a hybrid technique that involves the use of standard acetate templates, used over digital radiographs on a LCD monitor. Materials and methodsPreoperative digital radiographs of the pelvis were taken with a 30mm diameter spherical metal ball taped onto the greater trochanter. Viewing the digital radiographs on a flat screen LCD monitor, the metal ball on the image was magnified to 30mm as per the scale on the acetate template. The size of the acetabular cup and the femoral stem were then directly read using standard techniques with the acetate templates. To assess accuracy, digital films of 54 hips were retrospectively templated and the estimated size of the implant was compared with the actual size used at surgery. Reliability of the method was tested with Intraclass Correlation Coefficient (ICC). ResultsUsing this technique, it was possible to accurately predict the acetabular cup size in 38/54 (70%) of the hips and to within 1 size in 96% of the hips. The femoral component size was accurately predicted in 24/54 (44%) of the hips and to within 1 size in 82% of the hips. When assessed by two independent observers, there was good intraobserver reliability (ICC value=0.96) and interobserver reliability (ICC value=0.93) for the acetabular templating as well as for the femur (ICC value of 0.93 for intraobserver reliability and ICC value of 0.88 for interobserver reliability). ConclusionIt was possible to accurately and reliably predict the size of the acetabular cup and the femoral stem, using standard acetate onlay templates on digital radiographs, without the use of digital templating software.

Variance in predicted cup size by 2-dimensional vs 3-dimensional computerized tomography-based templating in primary total hiparthroplasty.

BackgroundPreoperative total hip arthroplasty templating can be performed with radiographs using acetate prints, digital viewing software, or with computed tomography (CT) images. Our hypothesis is that 3D templating is more precise and accurate with cup size prediction as compared to 2D templating with acetate prints and digital templating software.MethodsData collected from 45 patients undergoing robotic-assisted total hip arthroplasty compared cup sizes templated on acetate prints and OrthoView software to MAKOplasty software that uses CT scan. Kappa analysis determined strength of agreement between each templating modality and the final size used. t tests compared mean cup-size variance from the final size for each templating technique. Interclass correlation coefficient (ICC) determined reliability of digital and acetate planning by comparing predictions of the operating surgeon and a blinded adult reconstructive fellow.ResultsThe Kappa values for CT-guided, digital, and acetate templating with the final size was 0.974, 0.233, and 0.262, respectively. Both digital and acetate templating significantly overpredicted cup size, compared to CT-guided methods (P < .001). There was no significant difference between digital and acetate templating (P = .117). Interclass correlation coefficient value for digital and acetate templating was 0.928 and 0.931, respectively.ConclusionsCT-guided planning more accurately predicts hip implant cup size when compared to the significant overpredictions of digital and acetate templating. CT-guided templating may also lead to better outcomes due to bone stock preservation from a smaller and more accurate cup size predicted than that of digital and acetate predictions.

Effect of stem sizing and position on short-term complications with canine press fit cementless total hip arthroplasty.

To determine the influence of stem sizing and positioning with early subsidence and stem complications with cementless (BFX) total hip arthroplasty (THA). Retrospective case series. Fifty-five dogs; 58 THAs. Eighty cobalt-chromium BFX THAs were reviewed, 58 met inclusion criteria. Implant size, positioning, and major complications within 12 months of surgery were recorded. Femoral canal flare (FCF), canal fill, stem angle, and subsidence at 3 months were measured from postoperative radiographs. Appropriateness of final stem size was assessed with digital templates. Odds ratios for associations were calculated. Mean ± SD coronal canal fill (Fillcor ) was 75% ± 6, FCF was 2.0 ± 0.3, and subsidence was 1.7 mm ± 2.6. Stem angulation ranged from 7° varus to 6° valgus, and 7° cranial to 3° caudal. Appropriately sized stems (n = 45) had a mean Fillcor of 78%. Major stem complications occurred in 12% of THAs. Femora with subsidence > 3 mm were 45.3 times more likely to develop postoperative stem complications (P = .02). Stems with varus angulation ≥ 5° were 12.5 times more likely to sustain intraoperative fissures (P = .03). Stems considered undersized based on postoperative digital templating were 5.6 times more likely to develop stem complications (P = .04) and 5.7 times more likely to subside > 3 mm (P = .03). Varus stem angulation should be avoided to prevent fissures. Canal fill is a poor indicator of optimal stem size and the current recommendation of >85% is unnecessarily high. Postoperative templating may be useful for assessing appropriateness of stem size.

L’usage de calques sur des radiographies digitales calibrées en orthostatisme améliore la précision de la planification des arthroplasties totales de hanche

BackgroundThe accuracy of preoperative templating with respect to leg length, femoral offset, and the size of femoral and acetabular components is essential to the success of total hip arthroplasty (THA). Traditionally, templating has been performed using printed film with acetate templates. However, preoperative templating designed by different prosthetic manufacturers cannot be used directly on the film due to varying acetate template amplification ratios. Computer-based templating needs specialized digital templating software, which has cost implications. To address these shortcomings, we bring forward several questions: (1) the accuracy of traditional manual templating combined with the calibrated digital radiograph for preoperative templating, (2) the inter- and intra-observer reliability of this method. HypothesisUsing calibrated digital radiograph with traditional manual templating improves the accuracy and reproducibility of preoperative templating for THA. Patients and methodsWe designed a stepwise method that combines the traditional manual templating with standing digital radiograph calibrated by a scaling ball. Two separate observers (XJL, QYG) analyzed data of 82 patients (109 THAs) who had undergone THA with preoperative templating using the calibrated digital templating. The intra- and inter-observer reliability was assessed by intraclass correlation coefficient. ResultsThe size of the acetate template acetabular based on our method was identical to the actual implanted acetabular size in 55.0% (XJL 110/218 [50.5%]; QYG 130/218 [59.6%]) of the cases indicating moderate accuracy. The intraclass correlation coefficient (ICC) for acetabular templating indicated almost perfect inter-observer (ICC=0.918 [95% CI, 0.893–0.937]) and intra-observer agreement (ICC=0.932 [95% CI, 0.912–0.947]). While the exact implanted femoral size was predicted in 55.3% (XJL 122/218 [56.0%]; QYG 119/218 [54.6%]) of the cases. The ICC for femoral component templating indicated almost perfect inter-observer (ICC=0.944 [95% CI, 0.927–0.957]) and intra-observer agreement (ICC=0.909 [95% CI, 0.883–0.930]). DiscussionThis new stepwise method may prove to be a more reliable preoperative design choice to accurately calibrate magnification with radiograph, and could solve the incompatibility of the preoperative template designed by different prosthetic companies for direct use with the x-ray film. The method described is practical, convenient, cost-effective and does not require specialised equipment or software, thus making it particularly suitable for use in underdeveloped settings. Level of evidenceLevel IV, case series without controls.

Does the tibia component design affect the need for offset stems in revision total knee arthroplasty?

The stem/keel location varies between anatomic and symmetric revision tibial baseplates. The current study investigates the impact of an anatomic versus symmetric stem location on the need for offset couplers in revision total knee arthroplasty. Hip to ankle standing radiographs and lateral radiographs of 75 patients were analyzed using digital templating software. The offset in the anterior-posterior as well as medial-lateral plane between the center of the tibial diaphysis and the stem of the tibial baseplate were determined for an anatomic and symmetric tibial baseplate, respectively. Measurements were repeated for 4 resection levels: tip of fibular head (0), 10mm (1), 15mm (2) and 20mm (3) below the tip of the fibula head. Anatomic tibial baseplates require less offset for resection levels up to the tip of the fibula: total offset 2.28 versus 5.44mm (p < 0.001). However, for defects that result in resection levels below the tip of the fibula symmetric tibial baseplates require less offset: resection level 1: 3.18 versus 2.4mm (p = 0.008), 2: 4.81 versus 1.67mm (p < 0.001) and resection level 3: 5.66 versus 1.52mm (P < 0.001). The current study suggests that while asymmetric anatomic tibial baseplates have benefits for revisions with minimal bone loss, symmetric tibial baseplates require less offset when larger bone defects are encountered.

Acetate templating on calibrated standing digital radiograph improves accuracy of preoperative templating for total hip arthroplasty

BackgroundThe accuracy of preoperative templating with respect to leg length, femoral offset, and the size of femoral and acetabular components is essential to the success of total hip arthroplasty (THA). Traditionally, templating has been performed using printed film with acetate templates. However, preoperative templating designed by different prosthetic manufacturers cannot be used directly on the film due to varying acetate template amplification ratios. Computer-based templating needs specialized digital templating software, which has cost implications. To address these shortcomings, we bring forward several questions: (1) the accuracy of traditional manual templating combined with the calibrated digital radiograph for preoperative templating, (2) the inter- and intraobserver reliability of this method. HypothesisUsing calibrated digital radiograph with traditional manual templating improves the accuracy and reproducibility of preoperative templating for THA. Patients and methodsWe designed a stepwise method that combines the traditional manual templating with standing digital radiograph calibrated by a scaling ball. Two separate observers (XJL, QYG) analyzed data of 82 patients (109 THAs) who had undergone THA with preoperative templating using the calibrated digital templating. The intra- and interobserver reliability was assessed by intraclass correlation coefficient. ResultsThe size of the acetate template acetabular based on our method was identical to the actual implanted acetabular size in 55.0% (XJL 110/218 [50.5%]; QYG 130/218 [59.6%]) of the cases indicating moderate accuracy. The intraclass correlation coefficient (ICC) for acetabular templating indicated almost perfect interobserver (ICC=0.918 [95% CI, 0.893–0.937]) and intraobserver agreement (ICC=0.932 [95% CI, 0.912–0.947]). While the exact implanted femoral size was predicted in 55.3% (XJL 122/218 [56.0%]; QYG 119/218 [54.6%]) of the cases. The ICC for femoral component templating indicated almost perfect interobserver (ICC=0.944 [95% CI, 0.927–0.957]) and intraobserver agreement (ICC=0.909 [95% CI, 0.883–0.930]). DiscussionThis new stepwise method may prove to be a more reliable preoperative design choice to accurately calibrate magnification with radiograph, and could solve the incompatibility of the preoperative template designed by different prosthetic companies for direct use with the x-ray film. The method described is practical, convenient, cost-effective and does not require specialized equipment or software, thus making it particularly suitable for use in underdeveloped settings. Level of evidenceLevel IV, case series without controls.

Fracture treatment: failing to plan is planning to fail

Numerous options are available for fracture stabilisation and every fracture is unique. In order to achieve optimal results following fracture repair, detailed preoperative planning is essential, allowing a tailored treatment plan to be established for each individual. Failure to plan both the surgical procedure and postoperative care adequately can be anticipated to lead to higher complication rates. This article, as the first in the series, gives an overview of different possible approaches to fracture stabilisation, including the traditional open reduction and internal fixation as well as more biological approaches. Many factors influence the approach chosen for a given patient and these are discussed here. Once a decision is made regarding the approach to be used, a specific stabilisation method must be chosen, and guidance is given regarding the broad categories that may be suitable for specific situations. Following this, planning of the surgical repair must take place; several methods are outlined ranging from use of the direct overlay method to digital templating. Subsequent articles in the series will give more specific detail regarding specific types and locations of fractures.