Predictors of Episode-of-Care Costs for Ankle Fractures.

Ankle fractures are one of the most resource-consuming traumatic orthopedic injuries. Few studies have successfully evaluated the episode-of-care costs (EOCC) of common traumatic orthopedic injuries. The objective of this study was to determine the EOCC associated with the surgical management of ankle fractures. A retrospective cohort study of 105 consecutive patients who underwent open reduction internal fixation of an isolated ankle fracture at a Canadian Level-1 trauma center was conducted. Episode-of-care costs were generated using an activity-based costing framework. The median global episode-of-care cost for ankle fracture surgeries performed at the studied institution was $3,487 CAD [IQR 880] ($2,685 USD [IQR 616]). Patients aged 60 to 90 years had a significantly higher median EOCC than younger patients (p = .01). Supination-adduction injuries had a significantly higher median EOCC than other injury patterns (p = .01). The median EOCC for patients who underwent surgery within 10 days of their injury ($3,347 CAD [582], $2,577 USD [448]) was significantly lower than the cost for patients who had their surgery delayed 10 days or more after the injury ($3,634 CAD [776], $2,798 USD [598]) (p = .03). Patient sex, anesthesia type, ASA score and surgeon's fellowship training did not affect the EOCC. This study provides valuable data on predictors of EOCC in the surgical management of ankle fractures. Delaying simple ankle fracture cases due to operating time constraints can increase the total cost and burden of these fractures on the healthcare system. In addition, this study provides a framework for future episode-of-care cost analysis studies in orthopedic surgery.

Local tissue concentrations of cefazolin during total joint arthroplasty: a systematic review.

BACKGROUND: Periprosthetic joint infections (PJI) following joint arthroplasty are now the leading cause of reoperation and are associated with serious morbidity to the patient, often requiring several staged operations and a prolonged course of parenteral antibiotics. Prophylactic administration of intravenous antibiotics before skin incision is arguably the most important measure to prevent PJI; however, the dose effectiveness of cefazolin in target tissue is not well known. We aimed to identify parameters affecting local tissue concentration (LTC) of cefazolin. METHODS: We performed a literature search using the following keywords: "orthopaedics," "orthopedic," "arthroplasty" and "cefazolin." We included studies that measured LTC of cefazolin from samples obtained during either a total knee or total hip arthroplasty. RESULTS: Of the 332 records screened, we included 10 studies that described LTC of cefazolin. The included studies evaluated dosing (n = 7), procedure type (n = 3), body mass index (n = 1) and tourniquet utilization (n = 1). CONCLUSION: Few studies have measured LTC levels of antibiotics (or levels of cefazolin) to validate current recommendations for antibiotic prophylaxis in orthopedic surgery. With infection as the leading reason for early reoperation or revision surgery, the parameters affecting LTC during orthopedic procedures need to be further assessed.

Episode-of-care costs of total hip arthroplasty: day surgery versus same-day admission.

BACKGROUND: Although day surgery (DS) total hip arthroplasty (THA) has good patient satisfaction and a good safety profile, accurate episode-of-care cost (EOCC) calculations for this procedure compared to standard same-day admission (SDA) THA are not well known. We determined the EOCCs for patients who underwent THA, comparing DS and SDA pathways. METHODS: We evaluated the EOCCs for consecutive patients who underwent DS or SDA THA for osteoarthritis or osteonecrosis performed by a single surgeon at 1 academic centre from July 2018 to January 2020. Patient demographic and clinical data were recorded, as were preoperative diagnosis, type of anesthesia, type of implant used, surgical time and estimated blood loss. We determined direct and indirect costs from time of arrival at the presurgical unit to hospital discharge. We determined the EOCCs using an ABC method. RESULTS: The study included 50 patients who underwent THA (25 DS, 25 SDA). The mean length of stay in the SDA group was 45.1 (standard deviation [SD] 21.4) hours. Differences were observed between the 2 groups in mean age, mean Charlson Comorbidity Index score, surgical technique and mean surgical time (p ≤ 0.001). The mean total EOCC for SDA THA was $10 911 (SD $706.12, range $9944.07-$12 871.95), compared to $9672 (SD $546.55, range $8838.30-$11 058.07) for DS THA, a difference of 11.4%, mostly attributable to hospital resources such as laboratory tests, radiologic studies and cost of the surgical admission. CONCLUSION: Day surgery THA is cost-effective in selected patient populations. With the savings identified in this study, every 10 additional DS THA procedures would save sufficient resources to perform an additional THA operation.

Predictors of Foot Acute Compartment Syndrome: Big Data analysis.

Acute compartment syndrome (ACS) in the foot is a challenging diagnosis and can lead to significant disabilities to patients. The present study aims to investigate the incidence, risk factors, demographics and association in the analysis of acute compartment syndrome (ACS) of the foot. We performed a retrospective review of the Trauma Quality Programs data from the American College of Surgeons including 70,525 patients who sustained a fracture of the foot from 2015 to 2018 (4 calendar years). Fasciotomies were performed in 0.7% of all foot fractures. Open fractures, crush injuries and multiple foot fractures were the strongest predictors of fasciotomies, with odds ratios of 2.38, 2.38 and 2.33 respectively. Being a male was associated with an increased likelihood of fasciotomies of 64% (p < .0001 O.R. = [1.42-1.90]), while a dislocation in the foot increased likelihood of fasciotomies by 48% (p = .0008 O.R. = [1.18-1.86]). Trauma centre level III had higher rate of fasciotomy than Tertiary Trauma centers. Multiple other factors were addressed while controlling for cofounders. This big data analysis provided information not previously reported on the risk factors, demographics, and clinical association of ACS in the foot.

Proton Pump Inhibitor Use and Associated Infectious Complications in the PICU: Propensity Score Matching Analysis.

OBJECTIVES: We aimed to evaluate the association between proton pump inhibitor (PPI) exposure and nosocomial infection (NI) during PICU stay. DESIGN: Propensity score matched analysis of a single-center retrospective cohort from January 1, 2017, to December 31, 2018. SETTING: Tertiary medical and surgical PICU in France. PATIENTS: Patients younger than 18 years old, admitted to the PICU with a stay greater than 48 hours. INTERVENTION: Patients were retrospectively allocated into two groups and compared depending on whether they received a PPI or not. MEASUREMENTS AND MAIN RESULTS: Seven-hundred fifty-four patients were included of which 231 received a PPI (31%). PPIs were mostly used for stress ulcer prophylaxis (174/231; 75%), but upper gastrointestinal bleed risk factors were rarely present (18%). In the unadjusted analyses, the rate of NI was 8% in the PPI exposed group versus 2% in the nonexposed group. After propensity score matching ( n = 184 per group), we failed to identify an association between PPI exposure and greater odds of NI (adjusted odds ratio 2.9 [95% CI, 0.9-9.3]; p = 0.082). However, these data have not excluded the possibility that there is up to nine-fold greater odds of NI. CONCLUSIONS: This study highlights the prevalent use of PPIs in the PICU, and the potential association between PPIs and nine-fold greater odds of NI is not excluded.

Cancellations and delays of emergent orthopedic operations at a Canadian level 1 trauma centre.

BACKGROUND: Day-of surgery cancellation (DOSC) is considered to be a very inefficient use of hospital resources and results in emotional stress for the patient. To examine opportunities to minimize the incidence of preventable cancellations - an indicator of quality of care - we assessed the incidence of and reasons for DOSCs over 3 months among inpatients and outpatients at a trauma orthopedic service. METHODS: This was a prospective study of 2 cohorts of patients, inpatients and outpatients, scheduled for emergent orthopedic surgery at a Canadian tertiary level 1 trauma centre from Jan. 1 to Mar. 31, 2020. Patient demographic characteristics, injury characteristics, delays until surgery and reasons for DOSCs were recorded. RESULTS: A total of 185 patients (100 males and 85 females with a mean age of 54 yr) were included in the study. There were 98 outpatients and 87 inpatients. Seventy-five (40%) of the scheduled procedures in the outpatient group and 34 (30%) of those in the inpatient group were cancelled. In both groups, more than 85% of the cancellations were because of prioritization of a more urgent orthopedic or nonorthopedic surgical case. The average operative delay for the outpatient group was 11.4 days, compared to 3.8 days for the inpatient group (p < 0.001). CONCLUSION: High DOSC rates were observed among both outpatients and inpatients. The main reason for delaying surgery was prioritization of a more urgent surgical case. Providing the orthopedic trauma service with a dedicated OR opened 6 days per week, along with extended hours of OR services to 1700 daily, might be effective at minimizing DOSCs.

Episode-of-care costs of total knee arthroplasty: Outpatient versus inpatient postoperative care protocol.

BACKGROUND: Total knee arthroplasty (TKA) is the most commonly performed joint replacement procedure in North America. Few studies have successfully evaluated the episode-of-care cost (EOCC) of common elective orthopedic procedures using an activity-based costing (ABC) framework. The objective of this study is to compare the EOCC of same-day discharge versus inpatient TKA using an activity-based costing methodology. METHODS: An observational case-control study was conducted comparing the EOCC of 25 consecutive patients who underwent same-day discharge (SDD) TKA and 25 consecutive patients who underwent same-day admission (SDA) TKA at an academic center. The EOCC was generated using an ABC framework. RESULTS: The median total EOCC for outpatient TKA was $7,243.26 CAD (IQR=614.12), while the median EOCC in the inpatient group was $8,303.94 CAD (IQR=1,157.77). The costs incurred secondary to the hospital admission were the main driver of the increased cost for inpatients. The mean length of stay for admitted patients was 2.45 days (SD=1,52). Patients in the outpatient group were younger (p < 0.01) and had a lower mean Charlson Comorbidity Index group (p = 0.01). There was no significant difference in gender, BMI, ASA scores, and complication rates between the two groups. CONCLUSION: Through the application of an ABC framework, this value-based healthcare study demonstrates that outpatient procedures are a cost-effective approach to knee arthroplasty. Our findings demonstrate that the total cost of outpatient TKA was on average 15% ($1,060 CAD) lower than the cost of TKA with the standard inpatient postoperative care protocol.

Tourniquet Use and Local Tissue Concentrations of Cefazolin During Total Knee Arthroplasty: A Randomized Clinical Trial.

Importance: Prophylactic administration of antibiotics before skin incision is an important component in the prevention of periprosthetic joint infection in arthroplasty surgery. For antibiotics to be effective, the local tissue concentration (LTC) must exceed the minimum inhibitory concentration of typical infecting organisms; however, the LTC of cefazolin during arthroplasty is poorly understood. Objective: To compare the systemic concentration of cefazolin in serum with the LTC in fat, synovium, and bone during primary total knee arthroplasty (TKA) while assessing the effect of tourniquet inflation. Design, Setting, and Participants: This prospective randomized clinical trial was conducted from March 1, 2022, to June 30, 2023, in patients undergoing TKA at a single academic center. Intervention: Total knee arthroplasty with or without a limb tourniquet. Main Outcomes and Measures: Systemic blood and local tissues from the surgical site (fat, synovium, and bone) were harvested at regular intervals during the surgery. The primary outcome was the LTC of cefazolin, quantified using the liquid chromatography-tandem mass spectrometry technique. Results: A total of 59 patients were included in the study, with 29 in the tourniquet group (mean [SD] age, 69.3 [9.6] years; 23 [79.3%] female) and 30 in the no tourniquet group (mean [SD] age, 69.9 [9.7] years; 21 [70.0%] female). In patients undergoing TKA without a tourniquet, the mean concentration of cefazolin in serum was 71.9 µg/mL (95% CI, 66.4-77.5 µg/mL), whereas the mean LTCs were 13.9 µg/g (95% CI, 12.1-15.7 µg/g) in fat, 27.7 µg/g (95% CI, 24.3-31.0 µg/g) in synovium, and 17.7 µg/g (95% CI, 14.8-20.5 µg/g) in bone. For patients undergoing TKA with a tourniquet, the mean concentration of cefazolin in serum was 72.0 µg/mL (95% CI, 66.3-77.7 µg/mL), and the mean LTCs were 9.9 µg/g (95% CI, 8.7-11.1 µg/g) in fat, 21.8 µg/g (95% CI, 18.7-25.0 µg/g) in synovium, and 13.0 µg/g (95% CI, 10.8-15.2 µg/g) in bone. The use of a tourniquet resulted in significantly lower mean LTCs by 60 minutes after cefazolin infusion (10.8 µg/g [95% CI, 9.1-12.4 µg/g] vs 16.9 µg/g [95% CI, 14.1-19.6 µg/g], P = .001 in fat; 18.9 µg/g [95% CI, 14.1-23.6 µg/g] vs 25.8 µg/g [95% CI, 21.4-30.3 µg/g], P = .03 in synovium; and 11.8 µg/g [95% CI, 9.3-14.2 µg/g] vs 19.4 µg/g [95% CI, 14.5-24.4 µg/g], P = .007 in bone). Conclusions and Relevance: In this randomized clinical trial, the concentration of cefazolin was lower in local tissues (fat, synovium, and bone) than in systemic blood, and the use of a limb tourniquet further significantly reduced these concentrations. Although the current prophylactic dosing regimen for cefazolin provides sufficient serum concentrations, the levels in the periarticular tissue during TKA may be insufficient to prevent periprosthetic joint infection. Trial Registration: ClinicalTrials.gov Identifier: NCT05604157.

Large Nodular Fasciitis of the Shoulder Presenting as Soft Tissue Sarcoma: A Case Report.

CASE: This case report describes a patient who presented with clinical and radiographic features of a soft tissue sarcoma of the shoulder. Despite having a painless and relatively large mass, a biopsy and resection revealed nodular fasciitis (NF). CONCLUSION: This is an unusual case of a painless 10 cm mass that histopathologically was diagnosed as NF in the upper extremity with proximity to the axillary nerve and posterior humeral circumflex vessels. The USP6 rearrangement was helpful in confirming the diagnosis. Careful clinical, radiographic, and pathologic correlation is necessary in diagnosing these relatively rare tumors. In cases where there are discordant findings, molecular markers can be very helpful.

Failure Modes in Orthopedic Oncologic Reconstructive Surgery: A Review of Imaging Findings and Failure Rates.

Limb salvage surgeries utilizing endoprostheses and allografts are performed for a variety of oncologic conditions. These reconstructions can fail and require revision for many reasons, which are outlined and classified into mechanical failures (soft tissue failures, aseptic loosening, structural failure), non-mechanical failures (infection, tumor progression), and pediatric failures (physeal arrest, growth dysplasia). Distinct radiologic and clinical findings define specific failure subtypes but are sparsely illustrated in the radiology literature. Specifically, an understanding of the organizational structure of the failure modes can direct radiologists' search for post-reconstruction complications, enhance an appreciation of their prognostic significance, and facilitate research by standardizing the language and conceptual framework around outcomes. The purpose of this review is to highlight the key radiologic findings and imaging studies of each failure mode in orthopedic oncologic reconstructive surgery in the context of risk factors, failure rates, prognosis and survival statistics, and clinical decision-making regarding chemotherapy, radiation, and revision surgery.

Telemedicine-guided forearm emergency decompressive fasciotomy for compartment syndrome.

INTRODUCTION: We highlight the utility of telemedicine and telementoring for the management of orthopaedic emergencies using a case of forearm compartment syndrome following a penetrating trauma in a northern Inuit community in Nunavik, Quebec, Canada. METHODS & RESULTS: As in many cases of compartment syndrome in rural settings, the patient was at a high risk of developing irreversible complications. A prompt diagnosis followed by an emergency decompressive fasciotomy was warranted. Using telemedicine and telementoring guidance, the diagnosis of compartment syndrome was made, and the patient's volar compartment was successfully decompressed by a local emergency physician in a timely manner. Subsequently, the patient was able to be safely transferred to a level 1 trauma centre for further surgical management. This included a second-look operative exploration, irrigation and debridement, completion of volar fasciotomy and ulnar nerve decompression. No complications were seen. DISCUSSION: Our experience highlights two important clinical implications. First, telemedicine can be successfully implemented to facilitate clinical diagnosis of surgical emergencies in the rural setting. Second, telementoring can effectively allow surgeons to guide physicians remotely to perform emergency decompressive fasciotomy, which can help salvage the affected limb and significantly decrease the risk of debilitating complications.

Diagnosis Accuracy for Compartment Syndrome: A Systematic Review and Meta-Analysis.

OBJECTIVE: To evaluate whether published studies support basing the diagnosis of compartment syndrome of the lower leg on clinical findings, intracompartmental pressure (ICP) monitoring, or both. DATA SOURCES: A PubMed/MEDLINE, Web of Science, and Embase search of the English literature from 1966 to February 2022 was performed. This used "lower extremity" or "leg" or "tibia" and "compartment syndrome" and "pressure" as the subjects. A manual search of the bibliographies was performed and cross-referenced with those used to formulate the American Academy of Orthopaedic Surgeons clinical practice guidelines. STUDY SELECTION AND EXTRACTION: Inclusion criteria were traumatic tibia injuries, presence of data to calculate the sensitivity, specificity, positive and negative predictive values of clinical findings and/or pressure monitoring, and the presence or absence of compartment syndrome as the outcome. A total of 2906 full articles were found, of which 63 were deemed relevant for a detailed review. Seven studies met all eligibility criteria. DATA SYNTHESIS: The likelihood ratio form of Bayes theorem was used to assess the discriminatory ability of the clinical findings and ICP monitoring as tests for compartment syndrome. The predictive value for diagnosing acute compartment syndrome was 21% and 29% for the clinical signs and ICP, respectively. When combining both, the probability reached 68%. CONCLUSIONS: The use of ICP monitoring may be helpful when combined with a clinical assessment to increase the sensitivity and specificity of the overall diagnosis. Previously accepted individual inference values should be revisited with new prospective studies to further characterize the statistical value of each clinical finding. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Hospital episode-of-care costs for hip fractures: an activity-based costing analysis.

Background: Despite the large impact of hip fracture care on hospital budgets, accurate episode-of-care costs (EOCC) calculations for this injury remains a challenge. The objective of this article was to assess EOCC for geriatric patients with hip fractures using an activity-based costing methodology and identify intraoperative, perioperative, and patient-specific factors associated with higher EOCC. Material and Methods: This is a retrospective cohort study involving a total of 109 consecutive patients with hip fracture treated surgically at a Canadian level-1 trauma center from April 2018 to February 2019. Clinical and demographic data were extracted through the institution's centralized data warehouse. Data acquisition also included direct and indirect costs per episode of care, adverse events, and precise temporal data. Results: The median total EOCC was $13,113 (interquartile range 6658), excluding physician fees. Out of the total cost, 75% was attributed to direct costs, which represented a median expenditure of $9941. The median indirect cost of the EOCC was $3322. Based on the multivariate analysis, patients not operated within the 48 hours guidelines had an increased length of stay by 5.7 days (P = 0.003), representing an increase in EOCC of close to 5000$. Higher American Society of Anesthesiology (ASA) scores were associated with elevated EOCC. Conclusion: The cost of managing a patient with geriatric hip fracture from arrival in the emergency department to discharge from surgical ward represented $13,113. Main factors influencing the EOCC included adherence to the 48-hour benchmark surgical delay and ASA score. High-quality costing data are vital in assessing health care spending, conducting cost effectiveness analyses, and ultimately in guiding policy decisions. Level of Evidence: Level III (3), retrospective cohort study.

Novel digital continuous sensor for monitoring of compartment pressure: a case report.

Case: The American Academy of Orthopaedic Surgeons has recently identified continuous intracompartmental pressure monitoring as 1 of the few means to assist in ruling out acute compartment syndrome (ACS). There are very few methods that allow this measurement. This manuscript describes the use of a new digital monitoring system for ACS in 3 patients. This minimally invasive device, the MY01 (NXTSENS, Montreal, Canada) is capable of continuously and precisely measuring variations in intracompartmental pressure. Conclusion: MY01 detected the occurrence of ACS at early-stage and expedited the timing of surgery for 2 patients. This tool also objectively excluded a suspected diagnosis of ACS in a medically comorbid patient, obviating the need for unnecessary fasciotomies and potential complications.

Time-to-Incision for Hip Fractures in a Canadian Level-1 Trauma Centre: Are We Respecting the Guidelines?

Background: Surgical intervention within 48 hours is recommended for hip fractures in the elderly in order to reduce post-operative complications and lower mortality rates. The purpose of this retrospective study is to explore the causes of surgical delays for acute geriatric hip fractures. Methods: This is a retrospective cohort study involving a total of 109 consecutive geriatric patients who sustained proximal femur fractures ("hip fractures"), who subsequently underwent definitive fixation. Clinical, demographic, and direct costing data were extracted via a modern system and electronic medical records on a centralized data warehouse. Surgical delays and length of stay were analyzed according to clinical variables. Results: The established benchmark of a time-to-surgery of less than 48 hours was respected for 63 (57.8%) patients. Patients on oral anticoagulant (ACO) waited significantly longer, on average 58 hours compared to 44 for non-anticoagulated patients (p = .007). Patients with higher ASA scores waited significantly longer (p = .0018). More importantly, patients treated within 48 hours were discharged significantly earlier, on average after 10 days compared to 16 days for patients who waited more than 48 hours before receiving surgical treatment (p = .003), regardless of the pre-operative waiting time. Conclusion: Fewer than 60% of patients received surgery within the 48-hour benchmark after being admitted for an acute hip fracture in a Level-1 trauma centre. Patients with more comorbidities waited longer and stayed longer in the hospital after surgery. Implementing strategic, evidence-based changes should be done using this data to improve care of this vulnerable population.

Tibial Tunnel Placement in ACL Reconstruction Using a Novel Grid and Biplanar Stereoradiographic Imaging.

BACKGROUND: Nonanatomic graft placement is a frequent cause of anterior cruciate ligament reconstruction (ACLR) failure, and it can be attributed to either tibial or femoral tunnel malposition. To describe tibial tunnel placement in ACLR, we used EOS, a low-dose biplanar stereoradiographic imaging modality, to create a comprehensive grid that combines anteroposterior (AP) and mediolateral (ML) coordinates. PURPOSE: To (1) validate the automated grid generated from EOS imaging and (2) compare the results with optimal tibial tunnel placement. STUDY DESIGN: Descriptive laboratory study. METHODS: Using EOS, 3-dimensional models were created of the knees of 37 patients who had undergone ACLR. From the most medial, lateral, anterior, and posterior points on the tibial plateau of the EOS 3-dimensional model for each patient, an automated and personalized grid was generated from 2 independent observers' series of reconstructions. To validate this grid, each observer also manually measured the ML and AP distances, the medial proximal tibial angle (MPTA), and the tibial slope for each patient. The ideal tibial tunnel placement, as described in the literature, was compared with the actual tibial tunnel grid coordinates of each patient. RESULTS: The automated grid metrics for observer 1 gave a mean (95% CI) AP depth of 54.7 mm (53.4-55.9), ML width of 75.0 mm (73.3-76.6), MPTA of 84.9° (83.7-86.0), and slope of 7.2° (5.4-9.0). The differences with corresponding manual measurements were means (95% CIs) of 2.4 mm (1.4-3.4 mm), 0.5 mm (-1.3 to 2.2 mm), 1.2° (-0.4° to 2.9°), and -0.4° (-2.1° to 1.2°), respectively. The correlation between automated and manual measurements was r = 0.78 for the AP depth, r = 0.68 for the ML width, r = 0.18 for the MPTA, and r = 0.44 for the slope. The center of the actual tibial aperture on the plateau was a mean of 5.5 mm (95% CI, 4.8-6.1 mm) away from the referenced anatomic position, with a tendency toward more medial placement. CONCLUSION: The automated grid created using biplanar stereoradiographic imaging provided a novel, precise, and reproducible description of the tibial tunnel placement in ACLR. CLINICAL RELEVANCE: This technique can be used during preoperative planning, intraoperative guidance, and postoperative evaluation of tibial tunnel placement in ACLR.

Femoral Tunnel Placement Analysis in ACL Reconstruction Through Use of a Novel 3-Dimensional Reference With Biplanar Stereoradiographic Imaging.

BACKGROUND: The femoral-sided anatomic footprint of the anterior cruciate ligament (ACL) has been widely studied during the past decades. Nonanatomic placement is an important cause of ACL reconstruction (ACLR) failure. PURPOSE: To describe femoral tunnel placement in ACLR through use of a comprehensive 3-dimensional (3D) cylindrical coordinate system combining both the traditional clockface technique and the quadrant method. Our objective was to validate this technique and evaluate its reproducibility. STUDY DESIGN: Descriptive laboratory study. METHODS: The EOS Imaging System was used to make 3D models of the knee for 37 patients who had undergone ACLR. We designed an automated cylindrical reference software program individualized to the distal femoral morphology of each patient. Cylinder parameters were collected from 2 observers' series of 3D models. Each independent observer also manually measured the corresponding parameters using a lateral view of the 3D contours and a 2-dimensional stereoradiographic image for the corresponding patient. RESULTS: The average cylinder produced from the first observer's EOS 3D models had a 30.0° orientation (95% CI, 28.4°-31.5°), 40.4 mm length (95% CI, 39.3-41.4 mm), and 19.3 mm diameter (95% CI, 18.6-20.0 mm). For the second observer, these measurements were 29.7° (95% CI, 28.1°-31.3°), 40.7 mm (95% CI, 39.7-41.8 mm), and 19.7 mm (95% CI, 18.8-20.6 mm), respectively. Our method showed moderate intertest intraclass correlation among all 3 measuring techniques for both length (r = 0.68) and diameter (r = 0.63) but poor correlation for orientation (r = 0.44). In terms of interobserver reproducibility of the automated EOS 3D method, similar results were obtained: moderate to excellent correlations for length (r = 0.95; P < .001) and diameter (r = 0.66; P < .001) but poor correlation for orientation (r = 0.29; P < .08). With this reference system, we were able to describe the placement of each individual femoral tunnel aperture, averaging a difference of less than 10 mm from the historical anatomic description by Bernard et al. CONCLUSION: This novel 3D cylindrical coordinate system using biplanar, stereoradiographic, low-irradiation imaging showed a precision comparable with standard manual measurements for ACLR femoral tunnel placement. Our results also suggest that automated cylinders issued from EOS 3D models show adequate accuracy and reproducibility. CLINICAL RELEVANCE: This technique will open multiple possibilities in ACLR femoral tunnel placement in terms of preoperative planning, postoperative feedback, and even intraoperative guidance with augmented reality.