Fluoroscopic Measurements Research Articles

Assessing the Accuracy and Reliability of the Fluoroscopic Ruler for Comminuted Femur Fractures: A Cadaveric Study.

Fixation of comminuted femur fractures may result in limb length discrepancy. Intraoperative fluoroscopic measurement of the contra-lateral femur with a ruler is commonly performed to establish a reference for femoral length. No evidence regarding the reliability and accuracy of this technique exists. This study aimed to assess the accuracy and interrater reliability of a fluoroscopic ruler in obtaining correct femoral length in a comminuted femoral shaft fracture model. Approximately 5 cm of bone was removed from the left femoral diaphyses of 8 cadavers. Seven orthopedic surgery residents and 2 attendings measured the length of the intact contralateral femur using a ruler under fluoroscopy. The ruler was then applied to the "fractured" femur with manual traction applied until femoral length matched the measured length of the contralateral femur. The resulting gap in the "fractured" femur was compared with the length of bone that had been resected. Data were analyzed using means, SDs, and intraclass correlation coefficients (ICCs). Fifty-seven measurements were collected. The mean difference between the measured fracture gap and the length of bone removed was 8.0±5.8 mm (range, 0-22 mm). Femoral length was accurate to 5 mm in 40% of cases, 10 mm in 70%, 15 mm in 81%, 20 mm in 98%, and 25 mm in 100%. The overall interrater reliability was poor (ICC, 0.11; 95% CI, 0.001-0.44). Despite poor interrater reliability, the fluoroscopic ruler resulted in a mean leg length discrepancy of 8.0±5.8 mm in this cadaveric study. [Orthopedics. 202x;4x(x):xx-xx.].

Fundus-to-Antrum Ratio Measured with Fluoroscopy within One Week after Endoscopic Sleeve Gastroplasty Predicts Total Body Weight Loss over Time.

Background and Aims: Endoscopic sleeve gastroplasty (ESG) is a minimally invasive bariatric procedure to induce weight loss through restrictive physiology. This study was designed to evaluate the fluoroscopic measurement of gastric dimensions after ESG as a predictor of Total Body Weight Loss (TBWL) over time. Methods: Post-ESG patients were enrolled prospectively between August 2013 and August 2019. An upper gastrointestinal (GI) fluoroscopy was obtained within 7 days after the procedure. Two blinded, independent radiologists reviewed fluoroscopic images and measured the gastric lumen transverse diameter in three separate areas of the fundus, body, and antrum. The primary outcome was achieving a TBWL of ten percent or more after ESG. Results: In total, 162 patients were included in the analysis (65% female) and had a mean body mass index (BMI) of 39 ± 6 at baseline. Patients had a mean maximum TBWL of 16.5 ± 8.3%. Respectively, 92%, 75%, and 50% of patients achieved a TBWL of 5%, 10%, or 15% or more. The mean post-procedural UGI gastric fundus/antrum transverse measurement ratio was 1.2 ± 0.6. A higher fundus-to-antrum ratio was significantly associated with a TBWL of 10% or more during follow-up in the multivariable model (OR 2.49, 95% CI 1.31-4.71; p-value 0.005). The prediction score based on the fundus-to-antrum ratio hd an area under the ROC curve of 0.79 (95% CI 0.75-0.83) for predicting a TBWL of 10% or more during follow-up. Conclusions: Measuring gastric the fundus/antrum ratio within one week of endoscopic sleeve gastroplasty (ESG) is a consistent and independent predictive measure of sustained TBWL during long-term follow-up.

Hip External Rotation Decreases Ischiofemoral Distance: A Positive Correlation Between Cadaveric and Fluoroscopic Studies

PurposeTo determine the effect of hip external rotation or extension/adduction on minimizing the ischiofemoral distance (IFD) and assess the correlation between cadaveric and fluoroscopic IFD measurements in difference hip positions. MethodsThis cadaveric study involved 33 hip joints from 17 embalmed cadavers. IFD, the distance between the lesser trochanter and lateral ischium, was measured in different hip positions: neutral, external rotation at 30° and external rotation at 60° with the hip in both neutral extension and adduction as well as 10° hip extension and 10° hip adduction. Difference in IFD related to positions and correlation between cadaveric and fluoroscopic measurement were analyzed. ResultsIFD measurements showed that the greatest reduction occurred at 60° of external hip rotation, with a significant difference observed only between neutral and 60° external rotation in cadaveric groups (7.60±4.68 vs 5.05±3.48, 95% CI, 0.14 to 4.96; p=0.036). No substantial difference was observed between extension and adduction positions . Positive correlations were observed between cadaveric and fluoroscopic measurements, especially in the neutral position (r=0.492, p=0.004), external rotation at 30° (r=0.52, p=0.002), external rotation at 60° (r=0.419, p=0.015), and the extension/adduction positions combined with neutral rotation (r=0.396, p=0.023). ConclusionThe IFD significantly decreased with increasing degrees of hip external rotation, particularly at 60°. No significant reduction was observed in the extension/adduction positions. Additionally, positive correlations were observed between cadaveric and fluoroscopic measurements for specific hip positions: neutral rotation, external rotation at 30° and 60°, and extension/adduction at 10° with neutral rotation. Clinical RelevanceSurgeons can use this knowledge to improve hip impingement assessment through radiography, focusing on positions where IFD reduction is most notable. Understanding the relationship between hip positions and IFD can enhance the diagnosis of ischiofemoral impingement syndrome and benefiting patient care and outcomes.

Effect of sequential burr passes on minimally invasive akin and first metatarsal dorsiflexion osteotomies

BackgroundMinimally invasive surgical (MIS) osteotomies are increasing as a surgical option for treating midfoot and forefoot conditions. This study aimed to evaluate the impact of each burr pass on the degree of correction, gap size, and alignment in MIS Akin and first metatarsal dorsiflexion osteotomies (DFO). MethodsMIS Akin and first metatarsal DFO were performed on ten cadaveric specimens. Fluoroscopic measurements included the metatarsal dorsiflexion angle (MDA), dorsal cortical length (MDCL), first phalangeal medial cortical length (PCML) and proximal to distal phalangeal articular angle (PDPAA). ResultsThe average decrease in PCML with each burr pass was as follows: 1.53, 1.33, 1.27, 1.23 and 1.13 mm at the 1st to 5th pass, respectively. The MDCL sequentially decreased by 1.80, 1.59, 1.35, 0.75, and 0.60 mm. The MDA consistently decreased, and the PDPAA incrementally became more valgus oriented. ConclusionOn average, a first metatarsal dorsal wedge resection of 4.7 mm and first phalangeal medial wedge resection of 2.9 mm was achieved after 3 and 2 burr passes, respectively. This data may aid surgeons determine the optimal number of burr passes required to achieve the desired patient-specific surgical correction.

Revision Patellar Tendon Reconstruction Using Hamstring Tendon Autograft

Background: Patellar tendon ruptures presenting in a chronic setting are rare events that impose technical surgical challenges due to proximal retraction of the patella, quadriceps muscle atrophy and contracture, and peripatellar adhesions. Various reconstruction techniques have been described using different grafts and fixation methods; however, there is a paucity of reported outcomes and there is no consensus on standard of care. Indications: The patient is a 36-year-old man who presented with a failed patellar tendon reconstruction 14 months after his initial surgery (performed 1 year after the initial injury) with functional weakness and loss of extension. The patient was indicated for a revision patellar tendon reconstruction due to persistent functional limitations. Technique Description: The revision patellar tendon reconstruction was performed with gracilis and semitendinosus tendon autografts harvested from the ipsilateral limb. Hardware was removed from the initial graft tunnels in the tibial tubercle and patella. Patellar height was estimated using fluoroscopic measurement of the contralateral patellar tendon length. The graft is first passed through the patellar tunnel, and the individual limbs of the graft are then both placed through the tibial tubercle tunnel. A sternal wire in a figure-of-eight configuration was used to progressively distalize the patella to match the native patellar height, and the graft was then tensioned and secured together. Results: The patient regained full range of motion at 2-year follow-up and was able to return to work and activities without functional limitations. Recent case series also using ipsilateral hamstring tendon autograft for chronic patellar tendon reconstruction report improved patient outcome scores, normal Insall-Salvati index, improved quadriceps strength, and high levels of patient satisfaction. Discussion/Conclusion: Chronic patellar tendon ruptures are technically challenging to treat, especially in the context of revision of a failed reconstruction. The technique presented in this video may aid orthopaedic surgeons in treating this rare but debilitating injury. Given the lack of high-quality evidence, future studies are needed to explore graft choices, graft fixation techniques, and postoperative protocols. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

John Charnley Award: A Quantitative Fluoroscopic Tool Improves Acetabular Fragment Positioning in Periacetabular Osteotomy

BackgroundRadiographic assessment of acetabular fragment positioning during periacetabular osteotomy (PAO) has been linked to hip survivorship. Intraoperative plain radiographs are time and resource intensive, while fluoroscopy can introduce image distortion affecting measurement accuracy. Our purpose was to determine whether intraoperative fluoroscopy-based measurements with a distortion correcting fluoroscopic tool improved PAO measurement targets. MethodsWe retrospectively reviewed 570 PAOs; 136 PAOs utilized a distortion correcting fluoroscopic tool, and 434 PAOs performed with routine fluoroscopy, prior to this technology. Lateral center-edge angle (LCEA), acetabular index (AI), posterior wall sign (PWS), and anterior center-edge angle (ACEA) were measured on preoperative standing radiographs, intraoperative fluoroscopic images, and postoperative standing radiographs. Defined target zones of correction were AI: 0-10°, ACEA: 25-40°, LCEA: 25-40°, PWS: negative. Postoperative correction in zones and patient-reported outcomes were compared using chi-square tests and paired t-tests, respectively. ResultsThe average difference between postcorrection fluoroscopic measurements and 6-week postoperative radiographs was 0.21° for LCEA, 0.01° for ACEA, and −0.07° for AI (all P < .01). The PWS agreement was 92%. The percentages of hips meeting target goals overall improved with the new fluoroscopic tool: 74%-92% for LCEA (P < .01), 72%-85% for ACEA (P < .01), and 69 versus 74% for AI (P = .25), though there was no improvement in PWS (85 versus 85%, P = .92). All patient-reported outcomes except PROMIS Mental Health were significantly improved at most recent follow-up. ConclusionsOur study demonstrated improved PAO measurements and target goals with the use of a distortion correcting quantitative fluoroscopic real-time measuring device. This value-additive tool gives reliable quantitative measurements of correction without interfering with surgical workflow.

Comparison of 3D Bone Position Estimation Using QR Code and Metal Bead Markers

To improve the accuracy of a 3D bone position estimation system that displays 3D images in response to changes in the position of fluoroscopic images, modified markers using quick response (QR) codes were developed. The aims of this study were to assess the accuracy of the estimated bone position on 3D images with reference to QR code markers on fluoroscopic images and to compare its accuracy with metal bead markers. Bone positions were estimated from reference points on a fluoroscopic image compared with those on a 3D image. The positional relationships of QR code and metal bead markers on the fluoroscopic image were compared with those on the 3D image in order to establish whether a 3D image may be drawn by tracking positional changes in radius models. Differences were investigated by comparing the distance between markers on the fluoroscopic image and that on the 3D image, which was projected on the monitor. The error ratio, which was defined as the difference in the measurement between the fluoroscopic and 3D images divided by the fluoroscopic measurement, was compared between QR code and metal bead markers. Error ratios for the QR code markers were 5.0 ± 2.0%, 6.4 ± 7.6%, and 1.0 ± 0.8% in the anterior-posterior view, ulnar side lateral view, and posterior-anterior view, respectively. Error ratios for the metal bead markers were 1.3 ± 1.7%, 13.8 ± 14.5%, and 4.7 ± 5.7% in the anterior-posterior view, ulnar side lateral view, and posterior-anterior view, respectively. The error ratio for the metal bead markers was smaller in the initial position (p < 0.01). However, the error ratios for the QR code markers were smaller in the lateral position and the posterior-anterior position (p < 0.05). In QR code marker tracking, tracking was successful even with discontinuous images. The accuracy of a 3D bone position estimation was increased by using the QR code marker system. QR code marker tracking facilitates real-time comparisons of dynamic changes in preoperative 3D and intraoperative fluoroscopic images.

Tongue base augmentation to improve swallow function in a cadaveric model.

To evaluate the feasibility of using Calcium Hydroxylapatite (CaHA) to augment the tongue base for patients with swallowing impairment due to tongue base atrophy. A fresh human cadaver was obtained through the institution's body donation program and baseline lateral fluoroscopic images were obtained. A total of 2 mL of CaHA (Prolaryn Plus) were injected into three sites of the base of tongue under flexible endoscopic guidance with a 22G, 1.5-inch needle (Monoject, Cardinal Health). Post-lateral fluoroscopic images were obtained and pharyngeal area (cm2) and tongue base to pharyngeal wall distance (cm) was measured pre- and postinjection using SwallowTail fluoroscopic measurement software (Belldev Medical). The procedure was easily performed and the CaHA flowed easily into the cadaveric tongue without evidence of extrusion. The pre-procedural pharyngeal area decreased from 24.36 to 23.14 cm after augmentation. The base of tongue to pharyngeal wall distance decreased from 2.21 to 1.32 cm after augmentation. Tongue base augmentation with CaHA may be a feasible adjuvant therapy for the management of swallowing impairment secondary to tongue base atrophy. Further investigation is necessary to evaluate the clinical safety and efficacy. 4.

A Stepwise Intraoperative Protocol to Minimize Complications after Volar Plating.

Background Although outcome of volar plating is generally good, care should be taken to avoid specific iatrogenic and preventable complications, with an incidence reporting averaging 15%. Flexor tendon rupture due to a prominent plate, extensor tendon rupture due to a dorsal protruding screw tips, cartilage lesions due to intra-articular screw placement, loss of reduction due to insufficient stability, and persisting ulnar pain with distal radioulnar joint instability due to unstable triangular fibrocartilaginous complex lesions or unstable ulnar styloid base fractures all have been described. Purpose We believe that a majority of these complications can be prevented by meticulous assessment of several intraoperative parameters during volar plating. Therefore, we introduce the WRIST protocol, a stepwise easy-to-remember manual that combines multiple fluoroscopic measurements to guide intraoperative decision making. Conclusion Large prospective studies of the "WRIST" protocol are needed for validation. But we believe that it may help surgeons to optimize surgical technique, functional and radiographic outcome, and prevent complications when treating distal radial fractures.

Spatial Anatomy of the Radial Nerve in the Extended Deltopectoral Approach.

The goal of this study was to define safe zones to prevent radial nerve injury in an extended deltopectoral approach. Relative distances of the upper margin (UMRN) and lower margin (LMRN) of the radial nerve to the proximal and distal borders of the pectoralis major and deltoid insertions were measured in 20 cadaveric arms. Four proximal humeral zones were identified (zone I, proximal border of the pectoralis major tendon to the proximal border of the deltoid tendon; zone II, proximal border of the deltoid tendon to the distal border of the pectoralis major tendon; zone III, distal border of the pectoralis major tendon to the distal border of the deltoid tendon; and zone IV, distal to the distal border of the deltoid tendon). On fluoroscopic measurement, mean distances between the UMRN and the proximal border of the pectoralis major tendon and the proximal border of the deltoid tendon were 71.6±2.1 mm and 26.2±2.5 mm, respectively. The incidence of the radial nerve in the spiral groove within each defined zone was as follows: zone I, 0%; zone II, 50%; zones III and IV, 100%. There was a significant association between anatomic zone and radial nerve entry into the spiral groove, χ2(3, N=88)=64.53, P<.001. The proximal border of the pectoralis major tendon to the proximal border of the deltoid tendon (zone I) is a safe location to avoid injury to the radial nerve. We recommend placing cerclage wires proximal to zone I from lateral to medial to avoid entrapment of the radial nerve. [Orthopedics. 2023;46(1):e31-e37.].

Reliability of Weight-Bearing Ultrasonography for Diagnosis of Lisfranc Joint Injuries: A Cadaveric Study

Category: Trauma Introduction/Purpose: Ultrasonography is increasingly used to evaluate the stability of various joint in the field of foot and ankle. This study aims to assess and compare the Lisfranc joint stability under stimulated weight bearing condition among progressive stages of Lisfranc ligamentous complex injuries. All the measurements were assessed using ultrasonography, fluoroscopy, and direct open measurement. We hypothesize that there is a correlation between ultrasonographic and fluoroscopic measurements, or between ultrasonographic and direct open measurements when performing stress evaluation of the Lisfranc instability. Methods: Twelve fresh below-knee amputated cadaveric specimens underwent ultrasound, fluoroscopic, and direct gross evaluation of the Lisfranc stability under simulated weight bearing condition. The assessment was first performed with all Lisfranc ligamentous complex intact and thereafter with sequential transection of the dorsal Lisfranc ligament, interosseous Lisfranc ligament, and plantar Lisfranc ligament. The simulated weight bearing condition was performed with 600N of force. The distances evaluated during the experimental set up were C1-M1, C2-M2, C1-M2, C1-C2 and M1-M2. All measurements were recorded in millimeter (mm). The ultrasound machine (GE, LOGIQ E-9 ultrasound machine, Chicago, Illinois, USA) was used to assess the Lisfranc stability by measuring the distances between the hyperechoic bone contours or the pre-defined landmark of the metatarsal and cuneiform bones. Correlations between 1) Ultrasound and fluoroscopic measurements, 2) Ultrasound and direct open measurements, and 3) Fluoroscopic and direct open measurements were evaluated using Pearson correlations coefficient. Results: Strong positive correlations between ultrasonographic and direct open measurements were found when assessed for C1-M1, C1-M2, C1-C2, M1-M2 (Pearson's correlation ranged from 0.73-0.97, p-values &lt;0.001). Strong positive correlations between ultrasonographic and fluoroscopic measurements were found when assessed for C1-M1 from dorsal, medial, and plantar aspect (Pearson's correlation ranged from 0.75-0.90, p-values &lt;0.001). Strong positive correlations between fluoroscopic and direct open measurements were found when assessed for C1-M1, C1-M2, C2-M2, M1-M2 (Pearson's correlation ranged from 0.77-0.93, p-values &lt;0.001). Inter-rater and intra-rater reliability for the ultrasonographic measurements between the MSK radiologist (TK) and the foot and ankle surgeon (JS) were substantial (ICC ranged from 0.81-0.98). Conclusion: Ultrasonography is a reliable and reproducible tool for diagnosing Lisfranc ligamentous complex injuries. Both ultrasonographic and fluoroscopic measurements appear to strongly correlate with values measured by direct open measurement. Based on these data, ultrasonography is likely to become a valuable point of care diagnostic tool due to its ability to readily and dynamically evaluate suspected Lisfranc ligamentous complex injuries, without radiation exposure.

Measurement of Stricture Dimensions Using a Visual Comparative Estimation Method With Biopsy Forceps During Endoscopy.

Estimation of the dimensions of endoscopic findings such as stricture diameter is largely subjective. Accurate assessment of stricture dimensions has multiple benefits including facilitating the choice of appropriately sized endoscopic therapies for treating stricture, properly tracking response to endoscopic therapies between procedures, and potentially even predicting outcomes of endoscopic therapy. Endoscopies performed in children with repaired esophageal atresia between August 2019 and August 2021 for which both (1) an endoscopic estimate of esophageal stricture diameter obtained by visual comparison with the known dimensions of the biopsy forceps and (2) an intraoperative esophageal fluoroscopy study were performed were included for analysis. Fluoroscopic stricture diameter measurements were manually obtained using a software ruler tool calibrated to the known dimensions of the intraluminal endoscope. Statistical concordance was calculated between the visual diameter estimates and the standard fluoroscopic stricture measurements. One hundred ninety-one endoscopies were included for analysis. Lin's concordance correlation coefficient was 0.92 (95% confidence interval: 0.89-0.94) between the visual diameter estimates and the fluoroscopic stricture measurements. Correlation was strongest for smaller to mid-sized stricture diameters. Use of the biopsy forceps as a visual reference of known dimensions enables accurate visual estimation of esophageal stricture diameter during endoscopy using commonly available tools, with high concordance with standard fluoroscopic measurement techniques.

Lumbar segment-dependent soft tissue artifacts of skin markers during in vivo weight-bearing forward-Backward bending.

Traditional optical motion capture (OMC) with retroreflective markers is commonly used to measure joint kinematics but was also reported with unavoidable soft tissue artifacts (STAs) when quantifying the motion of the spine. Additionally, the patterns of the STA on the lumbar spine remain unclear. This study aimed to 1) quantify the in vivo STAs of the human lower back in three-dimensional directions during weight-bearing forward–backward bending and 2) determine the effects of the STAs on the calculated flexion angles between the upper and lower lumbar spines and adjacent vertebrae by comparing the skin marker (SM)- and virtual bone marker (VM)-based measurements. Six healthy volunteers were imaged using a biplanar radiographic system, and thirteen skin markers were mounted on every volunteer’s lower back while performing weight-bearing forward–backward bending. The STAs in the anterior/posterior (AP), medial/lateral (ML), and proximal/distal (PD) directions were investigated. The flexion angles between the upper and lower lumbar segments and adjacent intervertebral segments (L2–L5) throughout the cycle were calculated. For all the participants, STAs continuously increased in the AP direction and exhibited a reciprocal trend in the PD direction. During flexion, the STA at the lower lumbar region (L4–L5: 13.5 ± 6.5 mm) was significantly higher than that at the upper lumbar (L1–L3: 4.0 ± 1.5 mm) in the PD direction (p < 0.01). During extension, the lower lumbar (L4–L5: 2.7 ± 0.7 mm) exhibited significantly less STAs than that exhibited by the upper lumbar region (L1–L3: 6.1 ± 3.3 mm) (p < 0.05). The STA at the spinous process was significantly lower than that on both sides in the AP direction (p < 0.05). The present results on STAs, based on dual fluoroscopic measurements in healthy adult subjects, presented an anatomical direction, marker location, and anatomic segment dependency, which might help describe and quantify STAs for the lumbar spine kinematics and thus help develop location- and direction-specific weighting factors for use in global optimization algorithms aimed at minimizing the effects of STAs on the calculation of lumbar joint kinematics in the future.

Fluoroscopic measurements of the glenohumeral joint position and space in true anteroposterior and axillary views – a reliability study

Two-dimensional (2D) fluoroscopy has been used in shoulder pathologies to estimate the humeral head position (HHP) in the true anteroposterior (AP) view. However, there is a lack of evidence regarding the reliability estimating it in the axillary view and in measuring the shoulder joint space width (JSW). True AP view images (n=36) of subjects with adhesive capsulitis were taken in supine in multiple arm abduction positions. The axillary view images (n=48) were taken in supine and prone in 75° of abduction. The HHP was assessed in the glenoid reference frame. The position and radius of the humeral head along with the superior, inferior, anterior, posterior, and middle JSWs were measured in each image. All the images were coded and randomly presented twice to a physiotherapist at a gap of 48-72 h for intra-rater reliability and to 2 therapists and an orthopaedic surgeon for inter-rater reliability. Reliability was expressed using intraclass correlation coefficients (ICC) and standard error of measurement (SEM). In both the views, inter-rater, and intra-rater reliability was excellent for the radius of the humeral head (inter-rater – 0.95-0.97 and intra-rater -0.98)], moderate (ICC: 0.70 and 0.76), and excellent (ICC: 0.89 and 0.93) for HHP. The reliability for JSWs was moderate to good (ICC: 0.66-0.82) for inter-rater and good to excellent (ICC: 0.75-0.95) for intra-rater analysis. The SEM for HHP and JSWs were &lt;0.4 mm for intra-rater analysis, and &lt;0.7 mm for inter-rater reliability in both views. The study demonstrated that the glenohumeral arthrokinematic parameters can be measured with good to excellent levels of reliability when using 2 D fluoroscopy. The study is part of a clinical trial (Clinical Trial Registry India: CTRI/2018/12/016657).

Use of portable ultrasonography for the diagnosis of lateral ankle instability.

Portable ultrasonography is increasingly used to evaluate ankle stability at the point of care. This study aims to determine the correlation of portable-ultrasonographic and fluoroscopic measurements of ankle laxity in a cadaveric ligament transection model of ankle ligament injury. We hypothesize that there is an association between portable-ultrasonographic and fluoroscopic measurements when performing stress evaluation of lateral ankle instability. Eight fresh-frozen below-knee amputated cadaveric specimens with intact proximal fibula underwent ultrasound and fluoroscopic evaluation of the ankle during anterior drawer and talar tilt testing. The assessment was first performed with all lateral ankle ligaments intact and thereafter with sequential transection of the anterior talofibular ligament, calcaneofibular ligament, and posterior talofibular ligament. The anterior drawer test was performed with both 50N and 80N of force, and talar tilt test was performed with 1.7 Nm of torque. Correlations between (1) portable-ultrasonographic and fluoroscopic measurements and (2) sequential transection of lateral ankle ligaments were evaluated using Spearman's rank correlations. The same statistical test was used to investigate the correlation between the ultrasonographic and the fluoroscopic measurements. The inter- and intra-observer agreement was assessed using the intraclass correlation coefficient through a two-way mixed-effects model with absolute agreement. Portable-ultrasonographic and fluoroscopic measurements increased as additional ligaments of the lateral ankle were transected (Spearman's rank correlation ranged from 0.74 to 0.81, 0.74 to 0.81, p-values < 0.001). Strong positive correlations between ultrasonographic and fluoroscopic measurements were found during the lateral ankle stability evaluation using anterior drawer and talar tilt testing (Spearman's rank correlation ranged from 0.81 to 0.85, 0.81 to 0.85, p-values < 0.001). Inter-rater (0.99, 95% CI: 0.98-0.99) and intra-rater reliability (0.97, 95% CI: 0.95-0.99) for the ultrasonographic measurements were substantial. In conclusion, there was a strong correlation found between ultrasonographic and fluoroscopic values measured during simulated anterior drawer and talar tilt test in a cadaveric ligament transection model. In this model, the portable-ultrasonographic measurement was found to be reliable for repeated measurements of the talar translation and the lateral clear space distance. Based on these data, ultrasonography is likely to become a valuable point of care diagnostic tool due to its ability to readily and dynamically evaluate suspected lateral ankle instability. Clinical Significance: The use of dynamic stress ultrasound to assess the anterior translation of the talus and the lateral clear space distance appears to be a reliable and repeatable technique to evaluate lateral ankle stability with a radiation-free, noninvasive, and low-cost manner.

A Comparison of Portable Ultrasonography and the Fluoroscopy for Evaluating Medial Ankle Instability: A Cadaveric Study

Category:Ankle; TraumaIntroduction/Purpose:Diagnosis of destabilizing deltoid ligament injuries remains challenging and is best identified with dynamic imaging techniques. This study aims to assess and compare medial clear space (MCS) distances in various stages of sequentially created supination external rotation (SER) ankle injury model using portable ultrasound (P-US) and fluoroscopy. We hypothesize that there is a strong correlation between the P-US and fluoroscopic measurements for the assessment of medial ankle instability in SER type ankle injury during the gravity stress test (GST), weight-bearing, or external rotation stress test.Methods:Ten cadaveric specimens were used for assessing medial ankle instability. The assessment was performed with all structures intact, and later with sequential transection of the anterior inferior tibiofibular ligament (Stage I), fibular (Weber-B fracture) (Stage II), posterior inferior tibiofibular ligament (Stage III), superficial deltoid ligament (Stage IVa), and deep deltoid ligament (Stage IVb). In all scenarios, the GST, external rotation stress test(45N), and Simulated weight-bearing condition(750N) were performed. The P-US measurement of the MCS was assessed at the anteromedial and inferomedial aspect of the ankle joint. Three different MCS distances were measured, as demonstrated in Figure 1. The fluoroscopic MCS measurements were assessed on a true mortise ankle view achieved during each loading condition. Spearman rank correlation was used to investigate the relationship between the P-US and fluoroscopic measurements. The inter- and intra-observer agreement was assessed using the intraclass correlation coefficient (ICC) through a two-way mixed-effects model with absolute agreement.Results:The P-US and fluoroscopic assessed medial ankle instability values during the GST, weight-bearing, and the external rotation stress test increased as the SER ankle injury stage progressed. The P-US values measured during all stress tests demonstrated a moderate to strong positive correlation with those measured with the fluoroscopy (Spearman's rank correlation ranged from 0.61-0.93, p-values <0.001). Inter-rater (P-US: 0.97, 95%CI: 0.96-0.98) and intra-rater reliability (P-US, 0.95, 95%CI: 0.94-0.96) for the P-US measurements were all substantial.Conclusion:The use of dynamic P-US to measure the MCS appears to be a reliable and repeatable technique. The P-US MCS measurement values measured in the SER ankle injury model during the GST, weight-bearing and the external rotation stress test are well correlated with those values measured with fluoroscopy. Therefore, the dynamic P-US with stress examination of the ankle has the potential to quantify medial ankle instability in a radiation-free, non-invasive, low cost, and point of care setting.

Accuracy of the tibiofemoral contact forces estimated by a subject-specific musculoskeletal model with fluoroscopy-based contact point trajectories

Accurate estimation of the tibiofemoral contact forces relies on exact kinematics and joint geometry. Subject-specific kinematic constraints representing contact point trajectories derived from fluoroscopic measurements during lunge are introduced in a musculoskeletal model of the lower limb and compared to generic kinematic constraints. The medial, lateral, and total contact forces during gait and squat are validated using the data of four patients with an instrumented prosthesis. The accuracy of the estimated contact forces (both with subject-specific and generic kinematic constraints) remains close to the level reported in the literature. The mean root mean square errors range from 0.32 to 0.52 body weights for gait and from 0.27 to 0.72 body weights for squat. The impact of the subject-specific contact point trajectories is not found substantial or consistent between patients and tasks. Indeed, the kinematics of the total knee prostheses remains close to the kinematics of a hinge joint and the contact point locations remain generally centred at 20 mm from the tibia centreline (close to the constant value defined in the generic constraints). The contact point trajectories are also suspected to differ between tasks (lunge vs. gait and squat). While the contact point trajectories have been reported to be sensitive model parameters, no clear improvement of the contact force accuracy is demonstrated on patients with instrumented prosthesis. The introduction (as kinematic constraints) of fluoroscopy-based contact point trajectories may be considered in cases where these trajectories are significantly altered, as reported for osteoarthritis patients.

Surgical anatomy of the axillary artery: clinical implications for open shoulder surgery

Axillary artery injury is a devastating complication related to anterior shoulder surgery and can result in significant morbidity and/or mortality. The purpose of our study was to evaluate the course of the axillary artery in relation to bony landmarks of the shoulder and identify variations in artery position with humeral external rotation. Dissection of 18 shoulders (9 fresh whole-body cadavers) with simulated vessel perfusion using radiopaque dye was performed. The axillary artery position was measured from multiple points including 2 points on the coracoid base (C1 and C2), 3 points on the coracoid tip (C3-C5), 4 points on the glenoid: superior, middle, and inferior glenoid (D1-D4), and 2 points on the lesser tuberosity (L1 and L2). Fluoroscopic measurements were taken and compared at 0° and 90° of external rotation (F1 vs. F1' and F2 vs. F2'). Manual and fluoroscopic measurements were compared with one another using Kendall's τb correlation. There were 6 male and 3 female cadavers with an average age of 67.2 ± 9.3 years (range: 49-77 years). The mean distance from the axillary artery to the coracoid base (C1 and C2) measured 21.1 ± 7.3 and 22.3 ± 7.4 mm, respectively, whereas the mean distance to the coracoid tip (C3, C4, and C5) measured 30.7 ± 9.3, 52.1 ± 20.2, and 46.5 ± 14.3 mm, respectively. Measurements relative to the glenoid face (D1, D2, and D3) showed a progressive decrease in mean distance from superior to inferior, measuring 31.6 ± 10.3, 16.5 ± 7.5, and 10.3 ± 7.3 mm, respectively, whereas D4 (inferior glenoid to axillary artery) measured 17.8 ± 10.7 mm. The minimum distance from the axillary artery to any point on the glenoid was as close as 4.1 mm (D3). There was a statistically significant difference in F1 (0° external rotation) vs. F1' (90° external rotation) (18.5 vs. 13.4 mm, P = .03). Kendall's τb correlation showed a strong, positive correlation between manual and fluoroscopic measurements (D4: 16.0 ± 12.5 mm vs. F1: 18.5 ± 10.7 mm) (τb = 0.556, P = .037). The axillary artery travels an average of 1-1.8 cm from the inferior glenoid margin, which puts the artery at significant risk. In addition, the artery is significantly closer to the inferior glenoid with humeral external rotation. Surgeons performing anterior shoulder surgery should have a thorough understanding of the axillary artery course and understand changes in the position of the artery with external rotation of the humerus.

Using Dynamic Portable Ultrasonography for the Diagnosis of Lateral Ankle Instability

Category:Sports; AnkleIntroduction/Purpose:Destabilizing injuries to the lateral ligament have relied on physical examination and radiographic stress test for diagnosis, with a focus on anterior translation and tilting of the talus relative to the tibial bone. Portable ultrasonography (PUS) has increasingly been used in the clinical setting, allowing dynamic and non-invasive evaluation. The primary aim of this study was to assess the anterior translation and tilting of the talus with PUS in various stages of lateral ankle ligamentous injury.Secondary, we compared the instability values measured with PUS with those measured on fluoroscopy. Third, we aimed to determine the optimal cutoff values of the PUS that distinguish stable from unstable state.Methods:8 fresh-frozen cadaveric specimens underwent PUS and fluoroscopic evaluation for lateral ankle stability. The assessment was done with all ligaments intact and later with sequential transection of the anterior-talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the posterior-talofibular ligament (PTFL). In all scenarios, 2 loading conditions were considered; 1) Performing the anterior drawer test under 50N and 80N of force, anterior translation was measured with PUS and fluoroscopy; 2) Performing the talar tilt test under 1.7Nm of torque, the lateral clear space (the distance between the fibular tip and lateral process of the talus) was measured with PUS, and the talar tilt angle was measured with fluoroscopy (Figure1).Pearson’s and Spearman’s rank correlation was used to determine the correlation. Youden’s J statistic was used to determine the optimal cutoff values for the PUS to distinguish intact or ATFL injury versus ATFL-CFL or ATFL-CFL-PTFL injuries under various loading conditions.Results:Strong positive correlations were found between PUS and fluoroscopic measurements (Pearson correlation:r=0.78- 0.85). PUS and fluoroscopic measurements during anterior translation and talar tilt test increased as additional ligaments were transected (Spearman’s rank correlation: anterior translation; r=0.74, p < 0.001: talar tilt; r=0.81, p<0.001). Inter-rater and intra- rater reliability for PUS and fluoroscopic measurements were all excellent (ICCs >=0.8). The optimal PUS cutoff values for distinguishing intact or ATFL injury from ATFL-CFL or ATFL-CFL-PTFL injuries were >=3.40mm (sensitivity 87.5%, specificity 81.25%) and >=4.78mm (sensitivity 87.5%, specificity 81.25%) of anterior talar translation under 50N and 80N of force respectively, as well as >=3.09mm (sensitivity 75%, specificity 93.75%) of the lateral clear space under 1.7Nm of torque.Conclusion:Portable ultrasonography for the diagnosis of lateral ankle instability was strongly correlated with fluoroscopic findings, and thus, can be a valuable diagnostic tool at the point of care. We recommend future in vivo research to investigate the accuracy of this new ultrasound application in a clinical setting.

Investigation of Lateral Column Lengthening Osteotomy on the Movement of the Calcaneus: A Cadaveric Study

Category:HindfootIntroduction/Purpose:Lateral column lengthening calcaneus osteotomy has been used widely in treating Stage IIB flexible flatfoot deformity in order to shift the anterior segment of the calcaneus forwards, which improves the coverage of the talonavicular joint by forefoot adduction. The premise of this investigation is that in addition to shifting the forefoot anteriorly around the axis of the talar head, there is also a posterior translation of the tuberosity of the calcaneus which is detrimental in that the angle of Gissane then impinges upon the posterior facet of the subtalar joint causing pain. Our hypothesis is that in addition to anterior translation of the calcaneus, posterior shift of the calcaneal tuberosity occurs with lengthening osteotomy of the calcaneus.Methods:An acute cadaveric flatfoot model was created on 5 fresh frozen cadaver feet with no previous foot and ankle deformity. In order to simulate the surgical scenario, the study was performed with no external load on the limb. A vertical osteotomy was performed 1 cm posterior of the calcaneocuboid joint. Commercially available precut wedges of 6 mm, 8 mm, 10 mm, and 12 mm were used for lateral column lengthening. After the insertion of the bone grafts, positional changes in sagittal plane of both the anterior and posterior calcaneus segments were monitored on lateral views under both fluoroscopy and a 3D digital high-resolution motion capture system. Results were calculated in percentage change from the base line horizontal distance between the talar and both anterior and posterior calcaneus markers before insertion of the wedges.Results:According to fluoroscopic measurements, the anterior translation of the anterior calcaneus segment was 7.27%+/-0.06 for 6 mm wedge, 16.11%+/-0.06 for 8 mm wedge, 20.81%+/- 0.08 for 10 mm wedge and 18.16%+/-0.07 for 12 mm wedge. The posterior translation of the posterior calcaneus segment was 9.85%+/-0.09 for 6 mm wedge, 13.15%+/-0.09 for 8 mm wedge, 12.04+/-0.09 for 10 mm wedge, and 14.06%+/-0.10 for 12 mm wedge. Statistical analysis showed that: 6 mm wedges did not cause significant changes in the translation of both anterior and posterior calcaneus segments with respect to the talus. 8 mm, 10 mm and 12 mm wedges caused significant translations both anteriorly and posteriorly. There was no statistically significant difference in the amount of either anterior or posterior translation caused by 8 mm, 10 mm or 12 mm wedges. These results were corroborated by 3D measurements.Conclusion:Of interest is that a 6 mm graft did not cause any significant anterior or posterior shift of the calcaneus. Lateral column lengthening with the 8,10, and 12 mm grafts however caused forward shifting of the anterior calcaneus, but also statistically significant posterior translation of the tuberosity, causing impingement of the posterior facet which was visible in each cadaver tested. There was no statistical difference between the sizes of the wedge above 6 mm and the translations they caused either anteriorly or posteriorly. Surgeons should be aware of the potential for painful impingement with the lateral column lengthening osteotomy.