Template-directed instrumentation in total knee arthroplasty: cost savings analysis

The environmental impact of hip and knee arthroplasty: An analysis of carbon emissions and disposal costs

BACKGROUND AND PURPOSE

The rise in hip and knee arthroplasty for osteoarthritis requires addressing healthcare system pollution to support Ireland's climate change goals. This research aimed to quantify waste generated and determine environmental and economic impacts to promote sustainable strategies in joint arthroplasty and shed light on the suboptimal waste management practices.

METHODS

The study was conducted at National Orthopaedic Hospital Cappagh (NOHC), measuring waste generated during hip and knee arthroplasty. Clinical, domestic, and recycled waste weights were recorded, including the segregation of Central Sterile Supply Department (CSSD) Blue Wrap waste in ten operations. Kilograms of carbon dioxide emissions (kgCO2e) and disposal costs were calculated.

RESULTS

In a sample of 100 joint arthroplasty operations, the study found that revision knees produced 23.58 ​kgCO2e per case, revision hips 23.50 ​kgCO2e, primary knees 15.82 ​kgCO2e, and primary hips 14.64 ​kgCO2e. CSSD Blue Wrap contributed on average 13.5% of OT waste. Extrapolating these findings to the estimated number of joint arthroplasties performed in 2022 ​at NOHC (1556 hip and knee joint arthroplasties), the emissions were estimated to be 24,576 kgCO2e, with the cost of disposal up to €29,228. Strategies to mitigate this waste have been identified and proposed.

CONCLUSION

The research aimed to address the environmental impact of orthopaedic joint arthroplasties, offering strategies to reduce waste generation, carbon emissions, and cost. Utilising our methodology to calculate greenhouse gas emissions will empower sustainability offices to conduct their own waste audits and implementing our strategies for waste management practices can help minimise environmental waste.

The accuracy of digital templating in the preoperative planning of total knee arthroplasties: A systematic review and meta-analysis

AIMS

Accurately predicting the implant size in total knee arthroplasties could increase the efficiency of the operation, decrease the costs associated with the procedure and result in improved patient outcomes. To substantiate its continued use, digital templating must demonstrate itself to be an accurate tool in predicting component size in order for surgeons to confidently use it to optimize the procedure.

METHODS

A systematic literature review was performed and identified 16 studies within the Pubmed, Ebsco and Ovid-Embase databases, with 1189 TKR prostheses included for analysis. A quality of evidence assessment was performed on each study depending on the study design. A random effects meta-analysis model was used to pool overall implant accuracy and the reported inter-rater agreement when performing digital templating and displayed in a forest plot. Meta-regression was used analyze potential factors that may affect the accuracy of digital templating.

RESULTS

The pooled proportion of accurate templates with 0 margin of error was found to be 56% (52-61, 95CI), which increases to 96% (0.94-0.98, 95CI) when allowing for a 1 size margin of error. Subgroup analysis between femoral and tibial components concluded no statistically significant difference.

CONCLUSIONS

This study supports the continued use of digital templating for planning total knee arthroplasties and recommends further subgroup analysis of patient age, body mass index and sex against accuracy. This review was registered in the International Prospective Register of Systematic Reviews Database under ID: CRD420222367461. No funding was provided for the completion of this systematic review.

BACKGROUND

Templating in the preoperative planning of total knee arthroplasties is a vital step in ensuring maximum operative efficiency. A method that can accurately predict the required implant size within 1 size could improve theatre turnover, decrease costs and benefit patient outcomes. The current literature on the accuracy of digital templating in total knee arthroplasties lacks a systematic review calculating the overall accuracy of the process, this study aims to address this gap.

Validating a Novel 2D to 3D Knee Reconstruction Method on Preoperative Total Knee Arthroplasty Patient Anatomies

BACKGROUND

As advanced technology continues to evolve, incorporating robotics into surgical procedures has become imperative for precision and accuracy in preoperative planning. Nevertheless, the integration of three-dimensional (3D) imaging into these processes presents both financial considerations and potential patient safety concerns. This study aims to assess the accuracy of a novel 2D-to-3D knee reconstruction solution, RSIP XPlan.ai™ (RSIP Vision, Jerusalem, Israel), on preoperative total knee arthroplasty (TKA) patient anatomies.

METHODS

Accuracy was calculated by measuring the Root Mean Square Error (RMSE) between X-ray-based 3D bone models generated by the algorithm and corresponding CT bone segmentations (distances of each mesh vertex to the closest vertex in the second mesh). The RMSE was computed globally for each bone, locally for eight clinically relevant bony landmark regions, and along simulated bone cut contours. In addition, the accuracies of three anatomical axes were assessed by comparing angular deviations to inter- and intra-observer baseline values.

RESULTS

The global RMSE was 0.93 ± 0.25 mm for the femur and 0.88 ± 0.14 mm for the tibia. Local RMSE values for bony landmark regions were 0.51 ± 0.33 mm for the five femoral landmarks and 0.47 ± 0.17 mm for the three tibial landmarks. The RMSE along simulated cut contours was 0.75 ± 0.35 mm for the distal femur cut and 0.63 ± 0.27 mm for the proximal tibial cut. Anatomical axial average angular deviations were 1.89° for the trans epicondylar axis (with an inter- and intra-observer baseline of 1.43°), 1.78° for the posterior condylar axis (with a baseline of 1.71°), and 2.82° (with a baseline of 2.56°) for the medial-lateral transverse axis.

CONCLUSIONS

The study findings demonstrate promising results regarding the accuracy of XPlan.ai™ in reconstructing 3D bone models from plain-film X-rays. The observed accuracy on real-world TKA patient anatomies in anatomically relevant regions, including bony landmarks, cut contours, and axes, suggests the potential utility of this method in various clinical scenarios. Further validation studies on larger cohorts are warranted to fully assess the reliability and generalizability of our results. Nonetheless, our findings lay the groundwork for potential advancements in future robotic arthroplasty technologies, with XPlan.ai™ offering a promising alternative to conventional CT scans in certain clinical contexts.

Predictability of implant sizes during cruciate-retaining total knee arthroplasty using an image-free hand-held robotic system

The use of appropriately sized implants is critical for achieving optimal gap balance following total knee arthroplasty (TKA). Inappropriately sized implants could result in several complications. Robot-assisted TKA (RA-TKA) using CT-based pre-operative planning predicts implant sizes with high accuracy. There is scant literature describing the accuracy of image-free RA-TKA in predicting implant sizes. The purpose of this study was to assess the accuracy of an image-free robotic system in predicting implant sizes during RA-TKA. Patients who underwent cruciate-retaining RA-TKA for primary osteoarthritis, using an image-free hand-held robotic system were studied. The predicted and implanted sizes of the femoral component, tibial component and polyethylene insert, for 165 patients, were recorded. Agreement between robot-predicted and implanted component sizes was assessed in percentages, while reliability was assessed using Cohen's weighted kappa coefficient. The accuracy of the robotic system was 63% (weighted-kappa = 0.623, P < 0.001), 94% (weighted-kappa = 0.911, P < 0.001) and 99.4% (weighted-kappa = 0.995, P < 0.001), in predicting exact, ± 1 and ± 2 sizes of the femoral component, respectively. For the tibial component, an accuracy of 15.8% (weighted-kappa = 0.207, P < 0.001), 55.8% (weighted-kappa = 0.378, P < 0.001) and 76.4% (weighted-kappa = 0.568, P < 0.001) was noted, for predicting exact, ± 1 and ± 2 sizes respectively. An accuracy of 88.5%, 98.2% and 100%, was noted for predicting exact, ± 1 and ± 2 sizes of the polyethylene insert respectively. Errors in predicting accurate implant sizes could be multi-factorial. Though the accuracy of image-free RA-TKA with respect to alignment and component positioning is established, the surgeon's expertise should be relied upon while deciding appropriate implant sizes.

Optimizing spine surgery instrument trays to immediately increase efficiency and reduce costs in the operating room

Background

Over-crowded surgical trays result in perioperative inefficiency and unnecessary costs. While methodologies to reduce the size of surgical trays have been described in the literature, they each have their own drawbacks. In this study, we compared three methods: (1) clinician review (CR), (2) mathematical programming (MP), and (3) a novel hybrid model (HM) based on surveys and cost analysis. While CR and MP are well documented, CR can yield suboptimal reductions and MP can be laborious and technically challenging. We hypothesized our easy-to-implement HM would result in a reduction of surgical instruments in both the laminectomy tray (LT) and basic neurosurgery tray (BNT) that is comparable to CR and MP.

Methods

Three approaches were tested: CR, MP, and HM. We interviewed 5 neurosurgeons and 3 orthopedic surgeons, at our institution, who performed a total of 5437 spine cases, requiring the use of the LT and BNT over a 4-year (2017-2021) period. In CR, surgeons suggested which surgical instruments should be removed. MP was performed via the mathematical analysis of 25 observations of the use of a LT and BNT tray. The HM was performed via a structured survey of the surgeons' estimated instrument usage, followed by a cost-based inflection point analysis.

Results

The CR, MP, and HM approaches resulted in a total instrument reduction of 41%, 35%, and 38%, respectively, corresponding to total cost savings per annum of $50,211.20, $46,348.80, and $44,417.60, respectively.

Conclusions

While hospitals continue to examine perioperative services for potential inefficiencies, surgical inventory will be increasingly scrutinized. Despite MP being the most accurate methodology to do so, our results suggest that savings were similar across all three methods. CR and HM are significantly less laborious and thus are practical alternatives.

The Economic Impact of Standardization and Digitalization in the Operating Room: A Systematic Literature Review

Hospital face increased resource constraints and competition. This escalates the need for efficiency optimization especially in resource-intense areas, such as the Operating Room (OR). Efficiency cannot happen at expenses of patient outcomes. Innovative digital support systems (DSS) have been introduced into the market to support established standardization methods of intraoperative workflows further. This review aimed to analyze whether applied standardization methods and implemented DSS of intraoperative surgical workflows lead to increasing efficiency and demonstrate economic improvements. A systematic review of intraoperative surgical workflows standardization and digitalization was performed. Journal articles and reviews from 2000 to 2023 were retrieved from EBSCO, PubMed, and Scopus databases, as well as the internal database of Johnson & Johnson. 17 articles showed a significant increase in efficiency through standardization, which led to cost reductions between $70.20 to $3,516 per case without negatively impacting quality. Five additional articles on DSS demonstrated a significant positive impact on efficiency and quality. Reduction in OR-time between 6 to 22% per case was one main contributor. No literature on DSS revealed any correlated economic impact. Selected standardization methods and introduced DSS for intraoperative surgical workflows effectively increase efficiency while maintaining or even improving quality. Demonstrated cost-effectiveness of non-digital standardization methods across surgical areas requires more research on complex and resource-intensive procedures and the economic value of DSS to support hospital management's strategic decisions to overcome the increasing economic burden.

Preoperative radiographic parameters in the case of using a narrow-version femoral implant in total knee arthroplasty

BACKGROUND

Recently, total knee arthroplasty (TKA) designs that allow the use of narrow-version femoral implants have been introduced to avoid femoral overhang. The purpose of this study was to investigate the frequency of the use of narrow-version femoral implants and identify the difference in radiographic parameters between using a narrow-version femoral implant and a standard-version femoral implant in TKA.

METHODS

A retrospective study was conducted on 504 primary TKAs using a TKA system (Anthem or Persona) that allowed narrow-version femoral implants. Anteroposterior (AP) dimension, mediolateral (ML) dimension, and modified aspect percentage ratio (ML/AP dimension) of the distal femur in preoperative radiographs were compared between a standard-version group (n = 275) and a narrow-version group (n = 229). A cut-off value of a modified aspect percentage ratio indicating the need for a narrow-version femoral implant was determined using the receiver operating characteristic (ROC) curve.

RESULTS

Mean ML dimension was 80.9 ± 6.1 mm in the standard-version group and 77.3 ± 4.4 mm in the narrow-version group (p < 0.001). Mean modified aspect percentage ratio was 138.8 ± 8.1% in the standard-version group and 131.7 ± 6.3% in the narrow-version group (p < 0.001). The optimum cut-off point of the modified aspect percentage ratio for narrow-version femoral implants was 135.4% (sensitivity: 72.0%; specificity: 66.7%) for Anthem and 133.3% (sensitivity: 75.9%, specificity: 76.4%) for Persona.

CONCLUSION

In the narrow-version femoral implant group, the ML dimension and the mean modified aspect percentage ratio were smaller than in the standard-version femoral implant group. A smaller modified aspect percentage ratio of the distal femur in preoperative radiographs could predict the need for narrow-version femoral implants in TKA. It was suggested that the cut-off point could be suggested as 135.4% for Anthem TKA design and 133.3% for Persona TKA design. These radiographic parameters are cost-effective and easily applicable for planning a TKA.A smaller modified aspect percentage ratio of the distal femur in preoperative radiographs could predict the need for narrow-version femoral implants in TKA. The cut-off point was 135.4% for Anthem TKA design and 133.3% for Persona TKA design.

The SLIM Study: Economic, Energy, and Waste Savings Through Lowering of Instrumentation Mass in Total Hip Arthroplasty

BACKGROUND

Nearly 700,000 total hip arthroplasties (THAs) are annually performed in North America, costing the healthcare system >$15 billion and creating over 5 million tons of waste. This study aims to (1) assess satisfaction of current THA setup; (2) determine economic cost, energy cost, and waste cost of current setup and apply lean methodology to improve efficiency; and (3) design and test "Savings through Lowering of Instrumentation Mass (SLIM) setup" based on lean principles and its ability to be safely implemented into practice.

METHODS

A Needs Assessment Survey was performed. After review and surgeon input, the "SLIM" set was designed, significantly reducing redundancy. Eighty patients were randomized to either Standard or SLIM setup. Operating room time, blood loss, perioperative adverse events and complications, cost/case, instrument weight (kg/case), total waste (kg/case), case setup time, and number of times and number of extra trays required were compared between groups.

RESULTS

The SLIM setup was associated with the following savings: Cost = -$408.19/case; Energy = -7.16 kWh/case; Waste = -1.61 kg/case; Trays = -6 (758 kg/case). No differences in operating room time, blood loss, and complication rate were detected (P > .05) between groups. Setup time was significantly shorter with SLIM (P < .05) and extra instrumentation was opened in <5% of cases.

CONCLUSION

A more "minimalist approach" to THA can be safely implemented. The SLIM setup is efficient and has been openly accepted by our allied staff. Such setup can lead to 1,610 kg reduction in waste, 7,160 kWh, and $408,190 in savings per 1,000 THAs performed.

Accuracy of one-dimensional templating on linear EOS radiography allows template-directed instrumentation in total knee arthroplasty

BACKGROUND

Templating for total knee arthroplasty (TKA) is routinely performed on two-dimensional standard X-ray images and allows template-directed instrumentation. To date, there is no report on one-dimensional (1D) anteroposterior (AP) templating not requiring specific templating software. We aim to describe a novel technique and explore its reliability, accuracy and potential cost-savings.

METHODS

We investigated a consecutive series of TKAs at one institution between January and July 2019. Patients with preoperative low-dose linear AP EOS radiography images were included. Implant component sizes were retrospectively templated on the AP view with the hospitals imaging viewing software by two observers who were blinded to the definitive implant size. Planning accuracy as well as inter- and intra-observer reliability was calculated. Cost-savings were estimated based on the reduction of trays indicated by the 1D templating size estimations.

RESULTS

A total of 141 consecutive TKAs in 113 patients were included. Accuracy of 1D templating was as follows: exact match in 53% femoral and 63% tibial components, within one size in 96% femoral and 98% tibial components. Overall 58% of TKA components were planned correctly and 97% within one size. Inter- and intra-rater reliability was good (κ = 0.66) and very good (κ = 0.82), respectively. This templating process can reduce instrumentation from six to three trays per case and therefore halve sterilisation costs.

CONCLUSIONS

The new 1D templating method using EOS AP imaging predicts component sizes in TKA within one size 97% of the time and can halve the number of instrumentation trays and sterilisation costs.

Machine Learning Predicts Femoral and Tibial Implant Size Mismatch for Total Knee Arthroplasty

Background

Despite reasonable accuracy with preoperative templating, the search for an optimal planning tool remains an unsolved dilemma. The purpose of the present study was to apply machine learning (ML) using preoperative demographic variables to predict mismatch between templating and final component size in primary total knee arthroplasty (TKA) cases.

Methods

This was a retrospective case-control study of primary TKA patients between September 2012 and April 2018. The primary outcome was mismatch between the templated and final implanted component sizes extracted from the operative database. The secondary outcome was mismatch categorized as undersized and oversized. Five supervised ML algorithms were trained using 6 demographic features. Prediction accuracies were obtained as a metric of performance for binary mismatch (yes/no) and multilevel (undersized/correct/oversized) classifications.

Results

A total of 1801 patients were included. For binary classification, the best-performing algorithm for predicting femoral and tibial mismatch was the stochastic gradient boosting model (area under the curve: 0.76/0.72, calibration intercepts: 0.05/0.05, calibration slopes: 0.55/0.7, and Brier scores: 0.20/0.21). For multiclass classification, the best-performing algorithms had accuracies of 83.9% and 82.9% for predicting the concordance/mismatch of the femoral and tibial implant, respectively. Model predictions of greater than 51.0% and 47.9% represented high-risk thresholds for femoral and tibial sizing mismatch, respectively.

Conclusions

ML algorithms predicted templating mismatch with good accuracy. External validation is necessary to confirm the performance and reliability of these algorithms. Predicting sizing mismatch is the first step in using ML to aid in the prediction of final TKA component sizes. Further studies to optimize parameters and predictions for the algorithms are ongoing.

Approaches to the rationalization of surgical instrument trays: scoping review and research agenda

BACKGROUND

Surgical Tray Rationalization (STR) consists of a systematic reduction in the number of surgical instruments to perform specific procedures without compromising patient safety while reducing losses in the sterilization and assembly of trays. STR is one example of initiatives to improve process performance that have been widely reported in industrial settings but only recently have gained popularity in healthcare organizations.

METHODS

We conduct a scoping review of the literature to identify and map available evidence on surgical tray management. Five methodological stages are implemented and reported; they are: identifying research questions, identifying relevant studies, study selection, charting the data, and collating, summarizing and reporting the results.

RESULTS

We reviewed forty-eight articles on STR, which were grouped according to their main proposed approaches: expert analysis, lean practices, and mathematical programming. We identify the most frequently used techniques within each approach and point to their potential contributions to operational and economic dimensions of STR. We also consolidate our findings, proposing a roadmap to STR with four generic steps (prepare, rationalize, implement, and consolidate) and recommended associated techniques.

CONCLUSIONS

To the best of our knowledge, ours is the first study that reviews and systematizes the existing literature on the subject of STR. Our study closes with the proposition of future research directions, which are presented as nine research questions associated with the four generic steps proposed in the STR roadmap.

Algorithm based automatic templating is less accurate than manual digital templating in total knee arthroplasty

The purpose of the study was to evaluate the accuracy of a commercial automatic digital templating algorithm compared to manual digital templating in total knee arthroplasty (TKA). The study also evaluated if race and the presence of a standardized calibration marker on preoperative radiographs effect the accuracy of digital templating. One hundred twenty-five consecutive patients undergoing primary TKA were included in the study. Patient demographics, etiology of arthritis, and the presence of a standardized calibration marker on preoperative anteroposterior (AP) and lateral radiographs was recorded. Manual digital templating and the use of the "auto-knee" templating algorithm with "Traumacad" software was performed and recorded. Intraoperative sizes of the actual implants used were recorded. Pearson χ2 test was used to evaluate the accuracy of auto versus manual templating. Manual templating was within 1 size of the implant used intraoperatively for femoral and tibial implants 97.6% and 94.2% of the time, respectively. The "auto-knee" algorithm was within one size of the implant used for femoral and tibial implants 51.2% and 71.2% of the time, respectively. The presence of a standardized calibration marker on the AP view did not change accuracy of templating for both components. There was no difference in accuracy of templating between races. We caution surgeons from exclusively using an automatic algorithm as it is less accurate than manual templating for TKA.

Three-dimensional templating in hip arthroplasty: the basis for template-directed instrumentation?

INTRODUCTION

Computed tomography-based three-dimensional models may allow the accurate determination of the center of rotation, lateral and anterior femoral offsets, and the required implant size in total hip arthroplasty. In this cadaver study, the accuracy of anatomical reconstruction was evaluated using a three-dimensional planning tool.

MATERIALS AND METHODS

A total of eight hip arthroplasties were performed on four bilateral specimens. Based on a computed tomography scan, the position and size of the prosthesis were templated with respect to the anatomical conditions.

RESULTS

On average, all parameters were reconstructed to an accuracy of 4.5 mm and lie within the limits recommended in the literature. All prostheses were implanted with the templated size.

CONCLUSIONS

The exact anatomy of the patient and the required size and position of the prosthesis were precisely analyzed using a templating software. Based on the present findings, the development of template-directed instrumentation is conceivable using this method. However, further technical features (e.g., navigation or robot-assisted surgery) are required for improved precision for implant positioning.

Employee Acceptance of Use: A Precondition for Enhancing Therapy Effectiveness, Patient Safety, and Economic Efficiency

Introduction: From the workplace engineering sciences, it is evident that work efficiency, measured by the criteria efficiency and effectiveness of therapy, economy and patient safety, is determined mainly by staff acceptance of new technology and reengineered workflows. Accordingly, the aim of this study was to ascertain and assess differences in terms of the acceptance of alternative types of prosthesis instrument configurations, oriented around the research question: “Which product features and process effects determine a high level of employee acceptance of use?”

Materials and Methods: This study is designed as a before-and-after comparison, based on the usability engineering approach. In the first study phase, 46 employees participating in the process of providing instruments for a total knee arthroplasty (TKA) procedure were asked to examine the current working situation, using a standard instrumentation set, in terms of instrument handling, work burden, proneness to errors, patient risks, process efficiency, and effectiveness. In the second study phase, 20 weeks after having implemented a size-specific instrumentation set, the same 46 individuals were surveyed on the identical questions. Additionally, in both study phases the time needed to perform the sub-processes related to instrumentation logistics inside the operating room (OR) was measured, in order to identify process efficiency and cost-saving effects.

Results: By using standard sets only 30% perceived a need for improvement. After 20 weeks, only 8% of the employees were satisfied with the previous equipment and 69% regarded the standard set as being relatively error-prone, endangering patient safety. In addition, 85% regarded the effectiveness of the standard process as limited. Finally, 75% considered the effectiveness of the reengineered process to be significantly higher, and 69% drew attention to the reduction of handling disadvantages. Furthermore, the time needed for instrumentation logistics inside the OR estimated at about 13 min less when using size-specific sets. This effect on process efficiency cost savings or the generation of additional revenue by performing additional procedures. Based on these findings, an ergonomic decision-making model has been developed.

Conclusion: Innovative medical products such as size-specific instrumentation sets contribute to lower procedure costs and improved process efficiency in the operating room (OR). However, employee motivation to use a new technology as part of an optimized workflow organization, is crucial to achieving an enhanced level of effectiveness, efficiency and patient safety. Hence, it is advisable to enhance change-management efforts in order to reduce resistance to change and ensure the new technology is successful.

Agreement in component size between preoperative measurement, navigation and final implant in total knee replacement

Background

One of the possible causes of dissatisfaction reported by many patients after total knee replacement (TKR) is the lack of agreement between component size and bone structure. To avoid this complication and facilitate the procedure, preoperative planning with digitized templates is recommended. Surgical navigation indicates the best position and the most adequate size of arthroplasty and may therefore replace preoperative radiographic measurement. The objective of the study was to check agreement between the sizes of TKR components measured before surgery with digitized templates, the size recommended by the navigation and sizes actually implanted.

Methods

In 103 patients scheduled for TKR, preoperative full-limb radiography was performed to measure the mechanical and anatomical axes of the limb, femur and tibia. The most adequate size of the femoral and tibial components was planned by superimposing digitized templates. The size recommended in navigation and the size of the finally implanted components were also recorded.

Results

A high level of agreement was found between the sizes of femoral and tibial components measured by X-rays and in navigation (0.750 and 0.772, respectively) (intraclass correlation and Cronbach's alpha). Agreement between the sizes recommended by X-rays and navigation and those finally implanted was 0.886 for the femur and 0.891 for the tibia. Agreement levels were not different in cases with prior deformities of limb axis.

Conclusions

The high level of agreement found in component sizes between radiographic measurement with digitized templates and navigation suggests that preoperative X-ray measurement is not needed when navigation is used for placement of implants during TKR.

The translational potential of this article

Computer-assisted surgery may avoid preoperative measurement with templates in TKR.

Implementing a perioperative efficiency initiative for orthopedic surgery instrumentation at an academic center: A comparative before-and-after study

Optimizing surgical instrumentation may contribute to value-based care, particularly in commonly performed procedures. We report our experience in implementing a perioperative efficiency program in 2 types of orthopedic surgery (primary total-knee arthroplasty, TKA, and total-hip arthroplasty, THA).A comparative before-and-after study with 2 participating surgeons, each performing both THA and TKA, was conducted. Our objective was to evaluate the effect of surgical tray optimization on operating and processing time, cost, and waste associated with preparation, delivery, and staging of sterile surgical instruments. The study was designed as a prospective quality improvement initiative with pre- and postimplementation operational measures and a provider satisfaction survey.A total of 96 procedures (38 preimplementation and 58 postimplementation) were assessed using time-stamped performance endpoints. The number and weight of trays and instruments processed were reduced substantially after the optimization intervention, particularly for TKA. Setup time was reduced by 23% (6 minutes, P = .01) for TKA procedures but did not differ for THA. The number of survey respondents was small, but satisfaction was high overall among personnel involved in implementation.Optimizing instrumentation trays for orthopedic procedures yielded reduction in processing time and cost. Future research should evaluate patient outcomes and incremental/additive impact on institutional quality measures.

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.

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

BACKGROUND

Digital templating systems foster patient-specific measurements for preoperative planning.

QUESTIONS/PURPOSES

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).

METHODS

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.

RESULTS

By centering the scaling sphere on the acetabular component, an accurate cup size was achieved. A difference of 3.5 cm 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 28.72 kg/m² (standard deviation 6.26 kg/m²) and an average position of the center of the greater trochanter of 51% (standard deviation of 6%) from the anterior surface of thigh.

CONCLUSIONS

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 40 kg/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.

Pre-operative templating for knee arthroplasty shows low accuracy with standard X-rays

OBJECTIVES

The purpose of this study was to evaluate the accuracy and reliability of pre-operative templating in predicting the size of femoral and tibial components and the effect of coronal deformity on templating accuracy.

METHODS

This was a retrospective study of 39 pre-operative templates prepared by three different surgeons with different levels of training. The accuracy and reliability measures were evaluated by alpha and kappa coefficients of agreement. The analysis of the effect of coronal deformity on the accuracy of the template was measured by the Spearman's correlation test.

RESULTS

Templating was accurate for the femoral component in 28.21% of anterposterior (AP) radiographs and 35.90% of lateral radiographs. Kappa coefficients were respectively 0.111 (95% confidence interval [95%CI]: -0.19 to 0.241) and 0.200 (95%CI: -0.010 to 0.401), indicating poor agreement. Templating accuracy for the tibial component were, respectively, 37.61% and 47.01% for AP and lateral views. Kappa coefficients were 0.186 (95%CI: -0.070 to 0.379) for the AP view and 0.315 (95%CI: -0.199 to 0.431) for the lateral view, showing poor and slight agreement respectively. Considering a margin of error of ±1 sizes, the agreement level improved for all components, particularly for tibia, where agreement levels become very good. The inter-observer agreement was fair for all components, except for the lateral view of the femoral component, whose agreement was good. The Spearman correlation test showed no correlation between accuracy of templating and coronal deformity.

CONCLUSION

Pre-operative templating is an unreliable and inaccurate tool. There is no relation between coronal deformity and accuracy of templating.

Computed Navigation Guidance for Ankle Replacement in the Setting of Ankle Deformity

Total ankle replacement (TAR) has evolved over the past decade as a treatment for end-stage ankle arthritis with improved survivorship. Despite the improving outcomes, ankle deformity represents a challenge to the foot and ankle surgeon with increased risk of implant failure. The use of preoperative computer-assisted guidance has led to better understanding the 3-dimensional ankle anatomy and associated deformities and allows for reproducible, anatomic placement of the TAR components.

Preoperative Planning in Primary Total Knee Arthroplasty

Preoperative planning is of paramount importance in primary total knee arthroplasty. A thorough preoperative analysis helps the surgeon envision the operation, anticipate any potential issues, and minimize the risk of premature implant failure. Obtaining a thorough history is critical for appropriate patient selection. The physical examination should evaluate the integrity of the soft tissues, the neurovascular status, range of motion, limb deformity, and the status of the collateral ligaments to help determine the soft-tissue balancing and constraint strategy required. Standard radiographs, with a known magnification, should be obtained for preoperative total knee arthroplasty templating. Routine standing AP, lateral, and skyline radiographs of the knee can help the surgeon plan the bone cuts and tibial slope as well as the implant size and position at the time of surgery. In certain circumstances, such as severe coronal deformities, bone deficiencies, and/or extra-articular deformities, additional measures are frequently necessary to successfully reconstruct the knee. Constrained implants, metal augments, and bone graft must be part of the surgeon's armamentarium.

2D versus 3D templating in total knee arthroplasty

BACKGROUND

Preoperative digital templating in total knee arthroplasty (TKA) helps to determine the need of non-standard implants, prophesies the bony resections and helps to anticipate the intraoperative plan. Templating within the process of patient specific instrumentation (PSI) is fairly new and 2D planning has not been compared to PSI templating.

METHODS

94 patients underwent unilateral primary TKA with magnetic resonance imaging (MRI) based preoperative templating and PSI cutting blocks. Parallel to this, three observers templated all cases using digital planning on standard preoperative x-rays. The examiners templated all cases independently and were blinded to the component sizes used intraoperatively.

RESULTS

Three-dimensional (3D) templating was accurate in predicting the correct implant size in 100% of the cases. The femoral and tibial two-dimensional (2D) digital templating varied from 43.6% to 59.5% and 52.1% to 68% of the cases. When allowing ±1 difference, femoral 2D digital templating varied from 93.6% to 97.8% of the cases and ranged from 94.6% to 98.9% on the tibial side. All observers show "very good" correlation. The coefficient indicates a very good agreement in between the three observers.

CONCLUSION

3D templating has very high accuracy for the actual implant size prediction. Compared to this, 2D digital templating is an accurate method to approximately (±1 size) determine the size of TKA components. However, we judge this technique accurate enough, that 2D templating allows launching Template-directed instrumentation (TDI), while the examiner does not need a high level of clinical experience.

CLINICAL RELEVANCE

Within the process of digital planning, the surgeonmight focus evenmore on the upcoming operation.

Template-Directed Instrumentation Reduces Cost and Improves Efficiency for Total Knee Arthroplasty: An Economic Decision Analysis and Pilot Study

Template-directed instrumentation (TDI) for total knee arthroplasty (TKA) may streamline operating room (OR) workflow and reduce costs by preselecting implants and minimizing instrument tray burden. A decision model simulated the economics of TDI. Sensitivity analyses determined thresholds for model variables to ensure TDI success. A clinical pilot was reviewed. The accuracy of preoperative templates was validated, and 20 consecutive primary TKAs were performed using TDI. The model determined that preoperative component size estimation should be accurate to ±1 implant size for 50% of TKAs to implement TDI. The pilot showed that preoperative template accuracy exceeded 97%. There were statistically significant improvements in OR turnover time and in-room time for TDI compared to an historical cohort of TKAs. TDI reduces costs and improves OR efficiency.

Radiographic Outcomes of Preoperative CT Scan-Derived Patient-Specific Total Ankle Arthroplasty

BACKGROUND

Preoperative computer navigation and patient-specific instrumentation have had promising results in total knee arthroplasty and in a previous cadaveric total ankle arthroplasty (TAA) study. Potential benefits of patient-specific guides include improved implant alignment and decreased surgical time. The purpose of this retrospective case series was to evaluate the accuracy, reproducibility, and limitations of TAA tibia and talar implant placement and radiographic alignment using preoperative computed tomography (CT) scan-derived instrumentation in a clinical setting.

METHODS

Between 2012 and 2014, 42 consecutive TAA cases in 42 patients using preoperative CT scan-derived patient-specific plans and guides (PROPHECY, Wright Medical Technology, Memphis TN) were reviewed from a single center of foot and ankle fellowship-trained orthopaedic surgeons. TAA implants used included 29 intramedullary referencing implants (INBONE II, Wright Medical Technology) and 13 low-profile tibia and talar resurfacing implants (Infinity, Wright Medical Technology). All patients had standardized preoperative CT scans before surgery that were used to create custom surgical plans and 3-dimensional solid cutting guides and models. All patients had a minimum 3-month follow-up with weightbearing postoperative radiographs. Patient demographics were recorded, and coronal and sagittal alignments were compared among weightbearing preoperative radiographs, CT scan-derived surgical plans, and weightbearing postoperative radiographs using a digital picture archiving and communication system.

RESULTS

Average age for all patients was 63 ± 9 years, with a body mass index of 29.8 ± 5.9. Average total surgical time for all TAAs was 100 ± 11 minutes, with Infinity TAAs taking less time than INBONE II TAAs (92 vs 104 minutes; P < .05). Average preoperative coronal alignment was 1.9 degrees varus ± 6.4 (range, 14 degrees valgus to 10 degrees varus). Postoperative weightbearing alignments for all TAA cases were within ±3° of the predicted coronal and sagittal alignments from the CT scan-derived surgical plans. There were no significant differences in pre- or postoperative weightbearing alignments between INBONE II and Infinity TAA cases. Neutral coronal and sagittal alignments were obtained for all TAA cases regardless of preoperative deformity. Patient-specific surgical plans were accurate to within 1 size for tibia and talar implants used. Surgical plans predicted the actual tibia implant size used in 100% of INBONE II cases and 92% of Infinity cases. Plans were less accurate for talar implants and predicted the actual talar implant size used in 76% of INBONE II cases and 46% of Infinity cases. In all cases of predicted tibia or talar size mismatch, surgical plans predicted 1 implant size larger than actually used.

CONCLUSIONS

Results from this study provide early clinical evidence that preoperative CT scan-derived patient-specific surgical plans and guides can help provide accurate and reproducible TAA radiographic alignments. Talar implant sizing was not as accurate due to individual surgeon preference regarding the extent of gutter debridement. Similar to other modern computer navigation and patient-specific instrumentation systems, final coronal and sagittal alignments were within 3 degrees of the predicted surgical plans, and sizing was accurate within 1 implant size. Future studies are warranted to investigate the clinical and functional implications of patient-specific TAA and the overall cost-effectiveness of this technique.

LEVEL OF EVIDENCE

Level IV, retrospective case series.