Lateral Fluoroscopic Images Research Articles

Optimal caudal needle angulation for lumbar medial branch denervation: A 3D cadaveric and clinical imaging comparison study

BackgroundLumbar medial branch (MB) radiofrequency ablation is a common intervention to treat facetogenic low back pain. The consensus among spine pain interventionalists is that capturing a greater length of the MB correlates with a longer duration of pain relief. Therefore, there has been interest in defining optimal needle angles to achieve parallel cannula placement. Presently, there is inconsistency regarding the optimal caudal needle angles. ObjectivesThe objectives of this study were to: 1) use a dissection-based 3D modelling methodology to quantify optimal caudal needle angles from cadaveric models; and 2) compare optimal cadaver-derived caudal needle angles with real-world patient-derived needle angles. MethodsEighteen formalin embalmed lumbosacral spine specimens were dissected, digitized, and modelled in 3D. Virtual needles were simulated and placed parallel with the L1-L5 MBs. Cadaver-derived caudal needle angles were measured from the high-fidelity 3D models with optimally placed virtual needles. Lateral fluoroscopic images of patients (n = 200) that received lumbar MB denervation were reviewed to measure patient-derived caudal needle angles (L3-L5 MB levels). Descriptive statistics were used to analyze the cadaver (L1-L5 MB levels) and patient-derived (L3-L5 MB levels) caudal needle angles. The cadaver and patient-derived mean caudal needle angles for L3-L5 MB levels were compared. ResultsThere was variability in the cadaver-derived mean caudal needle angles. The lowest mean caudal needle angle was the L1 MB level measured at 41.57 ± 8.56° (range: 27.14° - 53.96°). The highest was the L5 MB level with a mean caudal needle angle of 60.79 ± 8.55° (range: 46.97° - 79.74°). A total of 123 patients were included and 369 caudal needle angles (L3-L5 MB levels) were measured and analyzed. There was variability in the patient-derived mean caudal needle angles. The patient-derived mean caudal needle angles were 29.18 ± 8.77° (range: 11.80° - 61.31°), 33.34 ± 7.23° (range: 16.40° - 54.15°), and 49.08 ± 8.87° (range: 26.45° - 76.95°) for the L3, L4, and L5 MB levels, respectively. There was a significant difference in mean caudal needle angle between cadaver and patient-derived needle angles at the L3, L4, and L5 MB levels. ConclusionsAnalysis of cadaver-derived needle angles versus patient-derived data suggests optimization of lumbar MB denervation requires greater caudal angulation to achieve parallel needle placement. Further research is required to assess the clinical implications.

Lateral to medial fluoroscopic view improves the accuracy of identifying the MPFL femoral footprint using Schottle's technique.

This study investigated the effect of different fluoroscopy settings on the accuracy of locating Schottle's point during medial patellofemoral ligament (MPFL) reconstruction. The centre of the MPFL femoral footprint was identified and marked on 44 dry femurs. Two standard true lateral knee fluoroscopic images were obtained: (1) medial to lateral (ML) and (2) lateral to medial (LM). The deviation between the anatomically determined MPFL femoral footprint and the fluoroscopically identified point was measured on both fluoroscopic images. An 'acceptable tunnel location' was defined as within a 5- or 7-mm margin of error from the anatomic MPFL footprint. Distal femoral morphometric dimensions were also measured using digital calipers. Statistical analysis determined discrepancies between techniques and their relation to femoral morphometry. The LM view yielded a significantly smaller distance between the anatomical MPFL footprint and Schottle's point compared to the ML view (3.2 ± 1.5 vs. 4.5 ± 2.1 mm, p < 0.001). The LM view achieved acceptable tunnel locations, meeting the 5-mm error criterion in 90.9% of cases, while the ML view achieved 65.9% (p < 0.001). Both views yielded acceptable tunnel locations at similar rates using the 7-mm error criterion (n.s.). The anatomic MPFL footprint was displaced towards the anterior and proximal location in the ML view in reference to the Schottle point. No correlation was observed between any of the morphometric measurements and the deviations. This study demonstrated that using the LM fluoroscopic view improves the accuracy of femoral tunnel placement when identifying the MPFL footprint via the Schottle technique. Adopting the LM view in surgical practice will help surgeons locate the anatomical femoral footprint accurately, replicating the native MPFL and enhancing clinical outcomes. Level 4, cadaveric study.

App-based analysis of the femoral tunnel position in ACL reconstruction using the quadrant method.

The purpose of this study was to examine the intra- and interobserver variability of an app-based analysis of the femoral tunnel position using the quadrant method in primary anterior cruciate ligament reconstruction. Between 12/2020 und 12/2021 50 patients who underwent primary anterior cruciate ligament reconstruction were included in this retrospective study. Intraoperative strictly lateral fluoroscopic images of the knee with marked femoral tunnel were analyzed by four observers using the quadrant method. For retest reliability analysis, measurements were repeated once by 2 observers after 4 weeks. The femoral tunnel position of all included patients averaged 27.86% in the depth relation and 15.61% in the height relation. Statistical analysis showed an almost perfect intra- and interobserver reliability in the depth and height relation. The ICC was 0.92 in the depth relation and 0.84 in the height relation. The Pearson's correlation coefficient in the depth and height relation of observer 1 (0.94/0.81) was only slightly different from the Pearson's correlation coefficient of observer 2 (0.92/0.85). The app-based tunnel analysis took on average 59 ± 16s per measurement. The femoral tunnel analysis with the app-based quadrant method has an almost perfect intra- and interobserver reliability. By smartphone camera, a fast and highly accurate, if necessary also intraoperative, control of the tunnel position can be performed. Level 3-diagnostic retrospective cohort study.

True lateral imaging during lumbar medial branch radiofrequency neurotomy: Interobserver reliability

BackgroundTrue lateral imaging (TLI), obtained by superimposing bilateral lumbar spine structures and aligning superior endplate cortical bone, requires deliberate rotational adjustments of the laterally positioned fluoroscope in both the axial and longitudinal planes. True lateral segmental imaging is necessary to depict true and accurate radiofrequency (RF) cannula positioning relative to bony anatomy during lumbar medial branch radiofrequency neurotomy (LMBRFN). ObjectiveTo determine the interobserver reliability of TLI during LMBRFN. MethodsThis was a retrospective review of a prospectively generated collection of lateral fluoroscopic images to determine the interobserver reliability of TLI during LMBRFN. Lateral fluoroscopic images were prospectively collected from 34 consecutive L4-5 and L5-S1 LMBRFN procedures during routine clinical practice. Employing International Pain and Spine Intervention Society (IPSIS) LMBRFN and TLI techniques, an RF cannula was positioned parallel to the L3 and L4 medial branches and the L5 dorsal rami. During the normal course of TLI, untrue and final true lateral segmental images were obtained and saved. An original data set of 100 pairs of true and untrue lateral images was reviewed to verify true laterality using established criteria; disagreement was resolved by consensus or discarding ambiguous cases. To measure interobserver reliability (Cohen's Kappa), two blinded expert reviewers independently reviewed the image set, identifying the true lateral image and the plane requiring correction. ResultsThe observers agreed upon 98/98 true lateral RF-segment images (Kappa score 1.0 [1.00,1.00]). The observers agreed upon 86/98 maneuvers to correct the untrue RF-segment image. The Kappa score for determining the most appropriate corrective maneuver was 0.76 (0.63,0.89), showing substantial interobserver agreement. ConclusionsThe true lateral image of the targeted RF segment during LMBRFN was reliably determined with perfect interobserver agreement. Interobserver agreement was substantial regarding the maneuver to achieve TLI.

Dorsal calcaneal wedge removal in zadek osteotomy: A cadaveric study

BackgroundInsertional Achilles tendinopathy (IAT) is a common pathology with multiple surgical interventions available for treatment. The Zadek, dorsal closing wedge calcaneal osteotomy (ZO) has been demonstrated to be effective treatment of IAT. There have been various recommendations in the literature as to what measurement of wedge removal should be considered ideal to produce greatest postoperative range of motion (ROM), thus postoperative biomechanical potential. Accordingly, the purpose of this cadaveric study was to assess the range of motion achieved after various measurements of wedge removal by ZO. MethodsThe ZO was performed on six cadaveric specimens. A 7.5 mm and 15 mm wedge osteotomy was marked and sequentially completed on each specimen. Lateral fluoroscopic imaging was utilized to take preoperative and postoperative ROM measurements for each osteotomy. Dorsiflexion (DF) and plantarflexion (PF) ROM arcs were measured for each wedge size and compared by t-test. Effect sizes were calculated by Cohen’s d analysis. ResultsMaximal DF was 110.87 ± 12.97 deg in the pre-osteotomy state. Removal of a 7.5 mm wedge improved DF by 8 deg to a mean 102.93 ± 13.81 deg (p = 0.08). Removal of a 15 mm wedge improved DF by 16 deg to a mean 95.96 ± 11.41 deg (p = 0.003). Cohen’s d and effect size calculation demonstrated a 7.5 mm wedge to have a small effect on DF, while a 15 mm wedge had a medium effect (0.29, 0.52 respectively). Maximal PF did not change significantly amongst the pre-osteotomy, 7.5 mm wedge, or 15 mm wedge positions. ICC was 0.96. ConclusionBased on the results presented in this study, removal of a 15 mm wedge with ZO yields significant and greater improvement in ROM than a 7.5 mm wedge. We hope the current study will better inform preoperative planning for ZO. Study typeProspective Cadaver Study. Level of evidenceV.

Disc Degeneration and Cervical Spine Intervertebral Motion: A Cross-Sectional Study in Patients with Neck Pain and Matched Healthy Controls.

While neck pain can be defined in clinical terms, in most cases the underlying pathophysiology is largely unknown. Regional cervical spine range of motion is often found to be reduced in patients with neck pain compared to persons without pain although it is not clear if the decreased range is cause or effect. Less is known about the role of intervertebral kinematics and how that might be related to the presence of disc degeneration. In this study, the prevalence of intervertebral disc degeneration and continuous cervical intervertebral motion were both measured utilizing quantitative fluoroscopy (QF) in patients with subacute or chronic neck pain (n = 29) and gender-matched healthy controls (n = 30). A composite disc degeneration (CDD) score was calculated for each participant from the first, neutral, lateral fluoroscopic image. Intervertebral motion sharing parameters of motion-sharing inequality (MSI) and motion-sharing variability (MSV) were derived from the active cervical motion sequences obtained while patients were seated. The objective was to determine if average age, CDD, MSI, and MSV values were correlated and if there were differences in these variables between the neck pain group and the healthy control group. Correlation analysis was conducted for age, CDD, MSI, and MSV in each group. Age was moderately correlated with MSV in cervical spine extension in patients only (r = 0.63, p < 0.001). There were no significant differences in the prevalence of disc degeneration (CDD) between patients, who had on average mild pain and related disability, and healthy controls (median CDD 2 both groups, p = 0.94). There were also no significant differences in either flexion or extension intervertebral motion-sharing inequality or variability (MSI or MSV) between groups as measured during active cervical motion.

Radiographic Landmark Measurements for the Femoral Footprint of the Medial Patellofemoral Complex May Be Affected by Visible Femoral Shaft Length on Lateral Knee Radiographs

To assess the effect of visible femoral shaft length on the accuracy of radiographic landmarks of the medial patellofemoral complex (MPFC). In 9 cadaveric knees, the MPFC footprint was exposed on the medial femur, and its proximal and distal boundaries were marked. Lateral fluoroscopic images of the knee were assessed in 1-cm length increments, beginning 1 cm proximal to the medial condyle and continuing proximally to 8 cm. The MPFC midpoint was described on each image relative to the posterior cortical line of the femur and a line perpendicular to this line through the proximal margin of the medial condyle. In addition, the MPFC midpoint was assessed relative to a line from the proximal posterior cortex to the midpoint of Blumensaat line. Using the posterior cortical line as a reference, the MPFC radiographic landmark moved anteriorly with decreasing visible femoral shaft on radiographs, particularly at 4 cm and less. However, no proximal-distal change was noted. Linear regression analysis demonstrated a relationship between visible femoral shaft and MPFC position on radiographs (R= 0.461, R2= 0.212, B= -0.636, P < .001). For every centimeter decrease in the visible femoral shaft, the radiographic MPFC footprint moved anteriorly by 0.636 mm. Receiver operating characteristic curve analysis revealed that a minimum of 4 cm of femoral shaft on lateral radiographs is required for accurate MPFC footprint localization (area under the curve= 0.80; sensitivity= 76.7%; specificity= 69.0%; P < .001). In contrast, no anterior-posterior change was seen when referencing a line from the proximal posterior cortex to the midpoint of Blumensaat line. When using the posterior cortical line to identify the midpoint of the MPFC, at least 4 cm of femoral shaft should be visible for accurate assessment. If less than 4 cm of shaft is visible, a line through the midpoint of Blumensaat line and the proximal posterior cortex can be used as an alternative method to estimate the position of the femoral footprint. As fluoroscopy is frequently used intraoperatively for MPFC reconstruction, our findings may serve as a guide when assessing femoral tunnel placement on fluoroscopy.

A Novel Patellar Tendon Reconstruction Technique Using Semitendinosus Allograft

A Novel Patellar Tendon Reconstruction Technique Using Semitendinosus Allograft

Radiographic Anatomy of the Lateral Ankle Ligament Complex: A Cadaveric Study

Category: Ankle; Sports Introduction/Purpose: Lateral ankle sprains are common orthopedic injuries that may progress on as chronic lateral ankle instability (CLAI). Great care must be taken to restore precise anatomic relationships of the lateral ankle ligament complex (LALC) in the surgical management of CLAI. This study aimed to quantify the radiographic relationships between the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and prominent osseous landmarks visible under fluoroscopy to assist in perioperative practices for minimally invasive surgery (MIS) for CLAI. Methods: Ten fresh frozen ankle specimens were dissected to expose the LALC and prepared by threading a radiopaque filament through the ligamentous footprints of the ATFL and CFL. Lateral ankle fluoroscopic images were obtained and digitally analyzed to define dimensional characteristics of the ATFL and CFL. Directional measurements of the ligamentous footprints relative to the lateral process of the talus and the apex of the posterior facet of the calcaneus were also calculated. Results: Dimensional measurements of the ATFL included a mean length of 9.3 mm, fibular footprint of 9.4 mm, and talar footprint of 9.1 mm. Dimensional measurements of the CFL included a mean length of 19.4 mm, fibular footprint of 8.2 mm, and calcaneal footprint of 7.3 mm. From the lateral process of the talus, the fibular attachment of the ATFL was found 13.3 mm superior and 4.4 mm posterior, while the talar attachment was found 11.5 mm superior and 4.8 mm anterior. From the apex of the posterior facet of the calcaneus, the fibular attachment of the CFL was found 0.2 mm inferior and 6.8 mm anterior, while the calcaneal attachment was found 14.3 mm inferior and 5.9 mm posterior. Conclusion: The ATFL and CFL were radiographically analyzed in a unique manner and localized in reference to two prominent osseous landmarks. These findings may assist in perioperative practices for keyhole incision placement and arthroscopic guidance.

Clinician accuracy in identifying essential laryngeal landmarks on swallowing fluoroscopy.

Identification of anatomical landmarks is essential for interpretation of video fluoroscopic swallow studies (VFSS). This investigation sought to confirm the location of essential laryngeal landmarks and determine clinician accuracy in structure identification on VFSS. A single human cadaver was used to generate unmarked standard lateral and anterior-posterior (AP) fluoroscopic images. Essential laryngeal structures (e.g., true vocal fold, arytenoid) were directly identified using a guidewire placed through an endoscope while obtaining corresponding marked fluoroscopic images. Licensed clinicians (speech-language pathologists [SLP], laryngologists) and trainees (otolaryngology residents, SLP clinical fellows [CF]) identified 18 structures (9 lateral, 9 AP) on unmarked images. Answers were compared to corresponding marked images. The percentage of accurate identification was calculated for each clinician and then compared between groups using t-tests. Twenty-four individuals (10 SLPs, 1 CF, 9 residents, 4 laryngologists) from six institutions completed structure identification. Mean overall accuracy was 41.7 ± 13.0% (range 18.8-68.8%). There were no significant differences in mean overall accuracy between trainees (41.9 ± 12.9%) and clinicians (42.0 ± 13.1%), p = .97, or between SLPs (45.5 ± 12.8%) and physicians (38.9 ± 12.3%), p = .22. On average, participants were significantly more accurate identifying structures on lateral view (53.1 ± 16.1%) than AP (27.3 ± 22.8%), p < .001. Less than half of participants accurately identified the laryngeal ventricle, cricoid, epiglottic petiole, and the anterior commissure on lateral view. The ability of certified clinicians and trainees to correctly identify essential anatomic landmarks on swallowing fluoroscopy may be poor. Future work is needed to identify how we can train clinicians on more accurate identification of essential anatomic structures on swallowing fluoroscopy.Level of Evidence: NA.

Poster 132: Femoral length on lateral knee radiographs influences accuracy of radiographic landmarks for MPFC reconstruction

Objectives: Accuracy of femoral tunnel positioning is critical during medial patellofemoral complex (MPFC) reconstruction, as even 5mm of malpositioning has been associated with altered patellofemoral contact pressures. To help identify the appropriate position for femoral tunnel placement, Schottle and others have described radiographic landmarks to identify the MPFC footprint on lateral knee radiographs. These measurements are based on an extension of the posterior cortical line, which can vary based on the length of the femur visible on the radiograph. Because the scope of view can vary between intraoperative imaging modalities, the aim of this study was to assess the effect of femoral length on the accuracy of radiographic landmarks of the MPFC. Methods: In 9 unpaired cadaveric knees, the MPFC footprint was exposed on the medial femur, and the proximal and distal boundaries of the footprint were marked. Lateral fluoroscopic images of the knee were obtained and assessed in 1 cm length increments, beginning 1cm proximal to the posterior condyle and continuing proximally to a femoral length of 8 cms. The MPFC midpoint was described on each image relative to the posterior cortical line of the femur and a line perpendicular to this line, relative to the proximal margin of the posterior condyle. Linear regression analysis was used to assess the effect of femoral length on the radiographic position of the MPFC. ROC curve analysis and Delong test were used, and the minimum amount of femoral length required on radiographs to accurately identify an anatomic femoral tunnel was determined using Youden’s J statistic. Results: Using the posterior cortical line as a reference, the radiographic description of the MPFC footprint moved anteriorly with decreasing femoral length on the radiographs, particularly at 4cm and less. However, no proximal-distal change was seen in relation to the line through the proximal margin of the posterior condyle with changing femoral lengths. Linear regression analysis showed a significant relationship between the femoral length and anterior radiographic position of the MPFC on radiographs (R = 0.461, R2 = 0.212, B= -0.636, p &lt; 0.001). The slope coefficient was -0.636 mm, indicating that for every cm decrease in femoral length, the actual anatomic footprint of the MPFC moves anteriorly by 0.636 mm in relation to the posterior cortical line. Furthermore, ROC curve analysis revealed that a minimum of 4 cm of femoral length on lateral radiographs is required to accurately localize the footprint of the MPFC (AUC 0.80; sensitivity 76.7 %; specificity 69 %; p &lt; 0.001). Conclusions: The radiographic landmarks for the MPFC femoral footprint can change depending on the length of the distal femur visible on radiographs. We found that at least 4cm of the femoral shaft should be visible for the radiographic landmarks to be accurate. As fluoroscopy is frequently used intraoperatively for MPFC reconstruction, our findings may serve as a guide for accurate femoral tunnel placement.

Cervical Spinal Immobilization: A Head-to-Head Comparison of a One-Step Spray-on Foam Splint Versus Structural Aluminum Malleable Splint Immobilization.

Cervical spine immobilization in a low-resource environment is difficult secondary to limited equipment, prolonged transportation, and secondary complications. A structural aluminum malleable (SAM) splint is commonly utilized because of its availability and multipurpose intention. A one-step spray-on foam immobilization technique (Fast Cast) has been shown to be effective in lower-extremity splinting. The aim of this study was to demonstrate the ability of the Fast Cast to effectively immobilize the cervical spine in a head-to-head comparison against the SAM splint. We hypothesized that there would be no difference in surgeon scoring between Fast Cast and SAM splints for the immobilization of the cervical spine. This was a cadaveric experimental comparative study that compared a SAM splint versus Fast Cast for the immobilization of an unstable cervical spine. Each of the three cadaveric specimens had a corpectomy without fixation performed. A board-certified emergency medicine physician specialized in disaster medicine performed all SAM immobilizations. An orthopedic surgeon performed Fast Cast immobilizations. Each method of immobilization was done on each cadaver. Lateral fluoroscopic imaging was taken before and after immobilization and after log roll/gravity stress. Five board-certified orthopedic surgeons served as graders to independently score each splint. A 5-point Likert scale based on 10 splinting criteria (50 total points possible) was utilized to evaluate cervical spine immobilization. The lead statistical analyst was blinded to the immobilization groups. The statistical significance was assessed via a Wilcoxon signed-rank test and chi-square Fisher's exact test with significance between groups set at α < .05. Inter-rater reliability of the Likert scale results was assessed with the interclass correlation coefficient. Inter-rater reliability for the current Likert scale in the evaluation of cervical spine stabilization was good (interclass correlation coefficient = 0.76). For the cumulative Likert scale score, Fast Cast (32 [28-34]) exhibited a higher total score than SAM (44 [42-47]; P < .01). Likewise, Fast Cast exhibited a greater likelihood of higher Likert scores within each individual question as compared to SAM (P ≤ 0.04). In 100% of cases, raters indicated that Fast Cast passed the gravity stress examination without intrinsic loss of reduction or splinting material, whereas 33% of SAM passed (P < .01). In 100% of cases, raters indicated that Fast Cast passed the initial radiographic alignment following immobilization, whereas 66% of SAM passed (P = .04). In 100% of cases, raters indicated that Fast Cast passed radiographic alignment after the gravity stress examination, whereas 47% of SAM passed (P < .01). The Fast Cast exceeded our expectations and was shown to be rated not equivalent but superior to SAM splint immobilization for the cervical spine. This has significant clinical implications as the single-step spray-on foam is easy to transport and has multifaceted applications. It also eliminates pressure points and circumferential wrapping and obstruction to airway/vascular access while immobilizing the cervical spine and allowing for radiographic examination. Further studies are needed for human use and application.

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.

Assessing in vivo flexion-extension quality of motion after cervical disc arthroplasty: a pilot study.

The quality of flexion-extension motion after cervical disc arthroplasty has been a subject of interest due to the number of available devices with different designs and kinematics. Previous studies of motion quality have been limited to measuring the range of motion using two radiographs taken at the extremes of flexion and extension. This is the first study evaluating the in vivo quality of index segment motion using fluoroscopic images collected over the arc of flexion-extension after M6-C cervical disc arthroplasty surgery. Eligible participants had previously undergone a single-level cervical disc arthroplasty surgery for degenerative cervical spine disease performed by the senior author. Study participants underwent dynamic lateral fluoroscopic imaging to capture the C2-C7 motion between maximal flexion and extension. The amount of motion contribution by individual segments to the C2-C7 motion (termed segmental motion fraction) and its variation throughout the arc of flexion-extension were compared between the index and adjacent segments. The shift of centre of rotation during the arc of motion was also assessed. Ten subjects with a mean age of 43.8 years old were recruited, with an average follow-up of 16.2 months at the time of fluoroscopy. The C2-C7 cervical spine had an average flexion-extension range of 66.7 degrees. The contribution of the index segment averaged over the flexion-extension arc of motion was 18.9% (peak contribution 24.4%) for the C5-C6 group; and 15.5% (peak contribution 25.5%) for the C6-C7 group. The mean cranial-caudal location of the centre of rotation progressively shifted in the cranial direction from C2-C3 to C6-C7 motion segment. Our results demonstrated physiologic quality of motion at the index segment and harmony among its neighbouring segments following cervical disc arthroplasty, without gearshift-like intermittent locking of the prosthesis during the arc of flexion-extension motion. This pilot study provides a basis for the design of future long-term studies with larger sample size to compare the quality of motion between different cervical disc prostheses using the concept of segmental motion fraction as a motion-quality metric.

Paper 06: Femoral length on lateral knee radiographs influences accuracy of radiographic landmarks for MPFC reconstruction

Objectives: Accuracy of femoral tunnel positioning is critical during medial patellofemoral complex (MPFC) reconstruction, as even 5mm of malpositioning has been associated with altered patellofemoral contact pressures. To help identify the appropriate position for femoral tunnel placement, Schottle and others have described radiographic landmarks to identify the MPFC footprint on lateral knee radiographs. These measurements are based on an extension of the posterior cortical line, which can vary based on the length of the femur visible on the radiograph. Because the scope of view can vary between intraoperative imaging modalities, the aim of this study was to assess the effect of femoral length on the accuracy of radiographic landmarks of the MPFC. Methods: In 9 unpaired cadaveric knees, the MPFC footprint was exposed on the medial femur, and the proximal and distal boundaries of the footprint were marked. Lateral fluoroscopic images of the knee were obtained and assessed in 1 cm length increments, beginning 1cm proximal to the posterior condyle and continuing proximally to a femoral length of 8 cms. The MPFC midpoint was described on each image relative to the posterior cortical line of the femur and a line perpendicular to this line, relative to the proximal margin of the posterior condyle. Linear regression analysis was used to assess the effect of femoral length on the radiographic position of the MPFC. ROC curve analysis and Delong test were used to determine ROC curve analysis and Delong test were used, and the minimum amount of femoral length required on radiographs to accurately identify an anatomic femoral tunnel was determined using Youden’s J statistic. Results: Using the posterior cortical line as a reference, the radiographic description of the MPFC footprint moved anteriorly with decreasing femoral length on the radiographs, particularly at 4cm and less. However, no proximal-distal change was seen in relation to the line through the proximal margin of the posterior condyle with changing femoral lengths. Linear regression analysis showed a significant relationship between the femoral length and anterior position of the MPFC on radiographs (R = 0.461, R2 = 0.212, B= -0.636, p &lt; 0.001). The slope coefficient was -0.636 mm, indicating that for every cm decrease in femoral length, the actual anatomic footprint of the MPFC moves anteriorly by 0.636 mm in relation to the posterior cortical line. Furthermore, ROC curve analysis revealed that a minimum of 4 cm of femoral length on lateral radiographs is required to accurately localize the footprint of the MPFC (AUC 0.79; sensitivity 76.7 %; specificity 69 %; p &lt; 0.001). Conclusions: The radiographic landmarks for the MPFC femoral footprint can change depending on the length of the distal femur visible on radiographs. We found that at least 4cm of the femoral shaft should be visible for the radiographic landmarks to be accurate. As fluoroscopy is frequently used intraoperatively for MPFC reconstruction, our findings may serve as a guide for accurate femoral tunnel placement.

Comparison of the accuracy of intraoperative lateral fluoroscopy versus postoperative computed tomography in spinal fusions.

This study compared the accuracy of intraoperative lateral fluoroscopic images versus postoperative computed tomography (CT) 3D studies in the treatment of thoracolumbar spinal fusions. In a tertiary care hospital (study duration 6 months), we compared the use of lateral fluoroscopic images with the postoperative CT scans in 64 patients with thoracic or lumbar fractures undergoing spinal fusions. Out of the 64 patients, 61% were lumbar followed by 39% thoracic fractures. In the lumbar spine, the accuracy of screw placement utilizing lateral fluoroscopy versus postoperative CT 3D was 97.4%, while in thoracic spine, accuracy was reduced to 84.4%. Of the 64 patients, just 4 (6.2%) patients demonstrated lateral pedicle cortex penetration, 1 (1.5%) patient had a medial pedicle cortex breach, while none exhibited anterior vertebral body cortex penetration. This study documented the efficacy of lateral fluoroscopy in intraoperative thoracic and lumbar spinal fixation as confirmed by postoperative CT 3D studies. These findings support the continued use of fluoroscopy rather than CT intraoperatively to lower the risk of radiation exposure to both patients and surgeons.

Fluoroscopic Categorization of Cementless Acetabular Component Positioning.

The purpose of this study was to evaluate a fluoroscopic method of angle of lateral opening (ALO) categorization based on identification of the visible portion of a pre-existing, circular recess within the metal shell of the BioMedtrix BFX acetabular component, which projects as an ellipse at clinically relevant ALO values. Our hypothesis was that there will be an association between the actual ALO and the categorization of ALO based on identification of the visible portion of the elliptical recess on a lateral fluoroscopic image at clinically relevant values. A custom plexiglass jig was fitted with a two-axis inclinometer and a 24 mm BFX acetabular component attached to its tabletop. Fluoroscopic reference images were obtained with the cup positioned at an ALO of 35, 45 and 55 degrees with a fixed 10 degrees of retroversion. Thirty study fluoroscopic images (10 images at each ALO) were obtained based on randomization at an ALO of 35, 45 and 55 degrees (±0.5 degrees) with 10 degrees of retroversion. The order of the study images was randomized, and a single, blinded observer categorized the 30 study images as representing an ALO of 35, 45 or 55 degrees by comparison to the reference images. Analysis showed perfect (30/30) agreement with a weighted kappa coefficient of 1 (95% confidence interval: -0.717 to 1). The results demonstrate that accurate categorization of ALO can be achieved using this fluoroscopic method. This method may prove to be a simple but effective method of estimating intraoperative ALO.

Radiographic Description of Soft Tissue Attachments around the Elbow.

Quantitatively define the radiographic locations of the major soft-tissue attachments about the elbow. In 10 cadaveric elbows, the attachments of the medial ulnar collateral ligament, lateral ulnar collateral ligament, annular ligament, triceps, and biceps were marked with radiopaque spheres. Measurements were made on calibrated AP and lateral fluoroscopic images from known osseous landmarks. On AP radiographs; the anterior bundle of the MUCL (aMUCL) measured 28.6mm (95% CI, 27. 5-29.8mm) from the humeral attachment to the midpoint of the MUCL ridge on the ulna and 14.3mm, (95% CI 13.0-15.5) to the olecranon. The LUCL was 39.9mm (95% CI, 38.6 - 41.1mm) from the humeral attachment to the supinator crest attachment and 8.9mm (95% CI, 8.1-9.8mm) to the lateral epicondyle. On the lateral radiographs, the humeral attachment of the aMUCL to the medial coronoid was 27.1mm (95% CI, 25.9-28.2mm) and 9.3mm (95%CI, 17.5 -21.2mm) to the tip. The LUCL humeral attachment to the supinator crest was 45.4mm (95%CI, 44.1-46.8mm). The LUCL humeral attachment was located 8.9mm (95%CI, 8.0-9.7mm) posterior from the anterior humeral line. The soft-tissue attachments about the elbow were reproducibly demonstrated on radiographs in relation to osseous landmarks and radiographic lines. The radiographic relationships will allow for improved identification of the ligament and tendon attachment sites of the elbow for intraoperative assessment and postoperative evaluation following reconstruction.

Stifle kinematics in 4 dogs with cranial cruciate ligament insufficiency treated by CORA-based leveling osteotomy.

The purpose of this study was to quantify three-dimensional (3D) stifle kinematics during walking in dogs with complete cranial cruciate ligament insufficiency (CCL-I) treated with a CORA-based leveling osteotomy (CBLO). Four client-owned dogs with unilateral complete CCL-I were prospectively enrolled. Custom digital 3D models of the femora and tibiae were created from pre-and postoperative computed tomographic scans for each dog. Lateral view fluoroscopic images were collected during treadmill walking preoperatively and 6 months after CBLO. Results were generated using a 3D-to-2D image registration process. Pre-and postoperative stifle kinematics (craniocaudal translation, extension angle) were compared to that of the unaffected contralateral (control) stifle. Force plate gait analysis was performed, and symmetry indices (SI) were calculated for peak vertical force (PVF) and vertical impulse (VI). After CBLO, craniocaudal femorotibial motion was reduced by a median (range) of 43.0 (17.0-52.6) % over the complete gait cycle. Median (range) PVF SI was 0.49 (0.26-0.56) preoperatively and 0.92 (0.86-1.00) postoperatively, and VI SI was 0.44 (0.20-0.48) preoperatively and 0.92 (0.82-0.99) postoperatively. CBLO mitigated but did not fully resolve abnormal craniocaudal translation; lameness was substantially improved at 6 months.

AAOS Management of Hip Fractures in Older Adults Evidence-based Clinical Practice Guideline.

AAOS Management of Hip Fractures in Older Adults Evidence-based Clinical Practice Guideline.