Intraoperative Fluoroscopic Images Research Articles

Fluoroscopic control allows for precise tunnel positioning in MPFL reconstruction.

In MPFL reconstruction, anatomical graft positioning is required to restore physiological joint biomechanics and patellofemoral stability. Considerable rates of non-anatomical femoral tunnel placement exist. The purpose of this study was to analyse whether intraoperative fluoroscopic control is applicable to reduce variability of femoral tunnel positioning. Femoral tunnel positions of 116 consecutive MPFL reconstructions applying intraoperative fluoroscopic images were analysed. Tunnel positions were determined by two independent observers according to Schöttle's radiographic measurement method. Mean positions, standard deviations and ranges were calculated to determine the variability of the tunnel positions. Interclass correlation coefficient (ICC) was calculated. The mean anterior/posterior distances from the anatomical insertion of the MPFL to the centre of the femoral tunnel were 2.34mm (range 0.0-5.9mm) and 1.7mm (range 0.1-7.3mm, SD 1.3) for proximal/distal deviations; 95.7% (111/116) of femoral tunnel positions were found to be within the anatomical insertion area defined by Schöttle. Interobserver tunnel position measurements were highly reliable (ICC: depth 0.979; height 0.979). The study demonstrates that intraoperative fluoroscopic control is a feasible and effective method that enables to create reproducible and precise anatomical femoral tunnel positions in MPFL reconstruction. Accordingly, the routine use of intraoperative fluoroscopy can be recommended. Furthermore, the results indicate Schöttle's method as a reliable method for intraoperative control and postoperative analysis of femoral tunnel positioning. IV.

Intraoperative assessment of closed reduction for developmental dislocation of the hip using 3-dimensional fluoroscopy.

Postoperative imaging for operatively treated developmental dislocation of the hip typically uses computed tomography or a magnetic resonance imaging (MRI). Neither imaging modality offers the ability to intervene intraoperatively. The 3-dimensional (3D) C-arm provides an attractive alternative providing immediate intraoperative feedback on the quality of a hip reduction. Our primary research question was to determine whether 3D fluoroscopy could assess hip position after closed reduction and spica casting. Secondary questions included whether reduction was maintained postoperatively when compared with postoperative MRI, and to determine the radiation dose received by the infant. We retrospectively identified 16 patients from 2010 to 2013 who underwent closed reduction and spica casting for a developmentally dislocated hip who underwent both intraoperative 3D fluoroscopy and postoperative MRI imaging. Scans were retrieved and assessed by a blinded pediatric orthopaedic fellow. Assessment of hip reduction was graded based on the modified Shenton line of the pelvis in axial plane images. Effective radiation doses between imaging modalities were compared using an anthropomorphic phantom. All hips were reduced on 3D fluoroscopic images. Comparing the intraoperative 3D scans with the postoperative MRI images all 16 hips were in the same position. At 12 weeks all hips were reduced and no signs of subluxation were identified on the plain anteroposterior radiograph. 3D fluoroscopy achieved the lowest effective dose of radiation per study measuring 0.3 mSv compared with 0.5 mSv for low-dose CT and 0.48 mSv for 60 seconds of live fluoroscopy. Accurate assessment of the quality of hip reduction is possible in the axial plane using 3D fluoroscopy with no significant loss of reduction in the early postoperative period. When comparing the effective radiation exposure to limited-cut computed tomography protocols, 3D fluoroscopy offers a low-dose alternative that may facilitate cost savings and early discharge. Diagnostic studies-investigating a diagnostic test; study of nonconsecutive patients with consistently applied gold standard; level III.

Post-operative Radiographs for Degenerative Lumbar Spinal Fusions?

A retrospective review of 70 consecutive lumbar degenerative surgical cases in which intraoperative fluoroscopic imaging was compared with immediate postoperative radiographs using a novel vertebral grid-coordinate system. Same-hospitalization postoperative standing lumbar AP and lateral radiographs do not appear to be cost-effective or to provide additional clinically relevant information when intraoperative fluoroscopy is utilized.

Interventional digital tomosynthesis from a standard fluoroscopy system using 2D-3D registration.

Interventional fluoroscopy provides guidance in a variety of minimally invasive procedures. However, three-dimensional (3D) clinically relevant information is projected onto a two-dimensional (2D) image which can make image interpretation difficult. Moreover, vasculature visualisation requires the use of iodinated contrast media which is nephrotoxic and is the primary cause of renal complications. In this article, we demonstrate how digital tomosynthesis slices can be produced on standard fluoroscopy equipment by registering the preoperative CT volume and the intraoperative fluoroscopy images using 2D-3D image registration. The proposed method automatically reconstructs patient-anatomy-specific slices and removes clutter resulting from bony anatomy. Such slices could provide additional intraoperative information which cannot be provided by the preoperative CT volume alone, such as the deformed aorta position offering improved guidance precision. Image acquisition would fit with interventional clinical work-flow and would not require a high X-ray dose. Experiments are carried out using one phantom and four clinical datasets. Phantom results showed a 3351% contrast-to-noise improvement compared to standard fluoroscopy. Patient results showed our method enabled visualization of clinically relevant features: outline of the aorta, the aortic bifurcation and some aortic calcifications.

Skeletal imaging following reconstruction of the posterior cruciate ligament: in vivo comparison of fluoroscopy, radiography, and computed tomography.

Intra- and postoperative validation of anatomic footprint replication in posterior cruciate ligament (PCL) reconstruction can be conducted using fluoroscopy, radiography, or computed tomography (CT) scans. However, effectiveness and exposure to radiation of these imaging modalities are unknown. The objective of this study was to evaluate the comparative effectiveness of fluoroscopy, radiography, and CT in detecting femoral and tibial tunnel positions following an all-inside reconstruction of the PCL ligament in vivo. The study design was a retrospective case series. Intraoperative fluoroscopic images, postoperative radiographs, and CT scans were obtained in 50 consecutive patients following single-bundle PCL reconstruction. The centers of the tibial and femoral tunnel apertures were identified and correlated to measurement grid systems. The results of fluoroscopic, radiographic, and CT measurements were compared to each other and accumulated radiation dosages were calculated. Comparing the imaging groups, no statistically significant difference could be detected for the reference of the femoral tunnel to the intercondylar depth and height, for the reference of the tibial tunnel to the mediolateral diameter of the tibial plateau and for the superoinferior distance of the tibial tunnel entry to the tibial plateau and to the former physis line. Effective doses resulting from fluoroscopic, radiographic, and CT exposure averaged 2.9mSv, standard deviation (±SD) 4.1mSv, to 1.3 ± 0.8mSv and to 3.6 ± 1.0mSv, respectively. Fluoroscopy, radiography, and CT yield approximately equal effectiveness in detecting parameters used for quality validation intra- and postoperatively. An accumulating exposure to radiation must be considered.

Intraoperative Fluoroscopic Imaging to Accurately Treat Cam Deformities: Correlation with 3D Computed Tomography

In the diagnosis and surgical treatment of cam-type femoroacetabular impingement (FAI), three-dimensional (3D) imaging is the gold standard for detecting and defining femoral head-neck junction malformations. Although intraoperative fluoroscopy is used by many surgeons to evaluate and verify adequate correction of the deformity, a meaningful, systematic approach has not been well defined. The purposes of this study were (1) to correlate radial reformatted computed tomography (CT) scans with six defined intraoperative fluoroscopic views prior to surgical correction to determine if fluoroscopy could adequately depict cam deformity, and (2) to define the influence of femoral version on the clock-face location of the maximum cam deformity on these views. A consecutive series of 50 hips (48 patients) that underwent arthroscopic treatment for symptomatic FAI by a single surgeon were analyzed. Each patient underwent a CT scan and six consistent intraoperative fluoroscopy views: three views in hip extension (medial and lateral deformities) and three views in hip flexion of 50° (anterior and posterior deformities). The alpha angles of each of the fluoroscopic images were correlated with the radial reformatted CT using a 3D software program. Femoral version was also assessed on CT studies. Statistical analysis was performed with Student's t-test, with P < .05 defined as significant. Fifty-two percent of patients were male, average age of 28 years (range, 15-56 years). The maximum mean alpha angle was 65° (range, 37°–93°) and was located on the anteroposterior (AP) 30° external rotation (ER) fluoroscopy view. The mean clock-face positions of each of the fluoroscopy views (standardized to the right hip) were AP 30° internal rotation, 11:45; AP 0° (neutral) rotation, 12:30; AP 30° ER, 1:00; flexion/0° (neutral) rotation, 1:45; flexion/40° ER, 2:15; and flexion/60° ER, 2:45. Increased femoral anteversion (>20°) was associated with a significant change in the location of the maximum alpha angle (1:45 vs. 1:15; P = .002). The described six fluoroscopic views are helpful in localization and visualization of the typical cam deformity from 11:45 to 2:45 and can be utilized to reliably confirm a complete intraoperative resection of cam-type deformity in most patients. These views correlate with preoperative 3D imaging, and may be of even greater importance in the absence of preoperative 3D imaging.

Intraoperative Fluoroscopic Imaging to Treat Cam Deformities

Background: In the diagnosis and surgical treatment of cam-type femoroacetabular impingement (FAI), 3-dimensional (3D) imaging is the gold standard for detecting femoral head-neck junction malformations preoperatively. Intraoperative fluoroscopy is used by many surgeons to evaluate and verify adequate correction of the deformity. Purpose: (1) To compare radial reformatted computed tomography (CT) scans with 6 defined intraoperative fluoroscopic views before surgical correction to determine whether fluoroscopy could adequately depict cam deformity, and (2) to define the influence of femoral version on the clock-face location of the maximum cam deformity on these views. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A consecutive series of 50 hips (48 patients) that underwent arthroscopic treatment for symptomatic FAI by a single surgeon were analyzed. Each patient underwent a CT scan and 6 consistent intraoperative fluoroscopy views: 3 views in hip extension and 3 views in hip flexion of 50°. The alpha angles of each of the fluoroscopic images were compared with the radial reformatted CT using a 3D software program. Femoral version was also defined on CT studies. Statistical analysis was performed using the Student t test, with P < .05 defined as significant. Results: Fifty-two percent of patients were male, average age 28 years (range, 15-56 years). The maximum mean alpha angle on fluoroscopy was 65° (range, 37°-93°) and was located on the anteroposterior (AP) 30° external rotation (ER) fluoroscopy view. In comparison, the mean CT-derived maximum alpha angle was 67° and was located at 1:15 (P = .57). The mean clock-face positions of each of the fluoroscopy views (standardized to the right hip) were AP 30° internal rotation, 11:45; AP 0° (neutral) rotation, 12:30; AP 30° ER, 1:00; flexion/0° (neutral) rotation, 1:45; flexion/40° ER, 2:15; and flexion/60° ER, 2:45. Increased femoral anteversion (>20°) was associated with a significant change in the location of the maximum alpha angle (1:45 vs 1:15; P = .002). Conclusion: The described 6 fluoroscopic views are very helpful in localization and visualization of the typical cam deformity from 11:45 to 2:45 and can be used to reliably confirm a complete intraoperative resection of cam-type deformity in most patients. These views correlate with preoperative 3D imaging and may be of even greater importance in the absence of preoperative 3D imaging.

Intraoperative CT in the assessment of posterior wall acetabular fracture stability.

Posterior wall acetabular fractures that involve 10% to 40% of the posterior wall may or may not require an open reduction and internal fixation. Dynamic stress examination of the acetabular fracture under fluoroscopy has been used as an intraoperative method to assess joint stability. The aim of this study was to demonstrate the value of intraoperative ISO computed tomography (CT) examination using the Siemens ISO-C imaging system (Siemens Corp, Malvern, Pennsylvania) in the assessment of posterior wall acetabular fracture stability during stress examination under anesthesia. In 5 posterior wall acetabular fractures, standard fluoroscopic images (including anteroposterior pelvis and Judet radiographs) with dynamic stress examinations were compared with the ISO-C CT imaging system to assess posterior wall fracture stability during stress examination. After review of standard intraoperative fluoroscopic images under dynamic stress examination, all 5 cases appeared to demonstrate posterior wall stability; however, when the intraoperative images from the ISO-C CT imaging system demonstrated that 1 case showed fracture instability of the posterior wall segment during stress examination, open reduction and internal fixation was performed. The use of intraoperative ISO CT imaging has shown an initial improvement in the surgeon's ability to assess the intraoperative stability of posterior wall acetabular fractures during stress examination when compared with standard fluoroscopic images.

The Value of Interpretation of Intraoperative Fluoroscopy by Radiologists During Pediatric Fracture Treatment

Orthopaedic surgeons frequently use intraoperative fluoroscopy to aid in the real-time decision-making process during fracture treatment. Radiologists routinely interpret and report on these fluoroscopic images. The goal of this combined retrospective and prospective study was to assess the value of this practice of having radiologists interpret intraoperative fluoroscopy for pediatric fracture treatment. In 500 consecutive pediatric patients who underwent fracture treatment in the operating room during a 1-year period, the following 4 parameters were retrospectively reviewed: (1) time between completion of procedure and availability of radiologist's report, (2) discrepancies between the surgeon-dictated operative report and the radiologist's report on the fluoroscopic images, (3) recommendations or unexpected findings in the radiologist's report, and (4) charges and reimbursement for the radiologist to report on the fluoroscopic images. In an additional 76 consecutive pediatric trauma patients, the number of intraoperative fluoroscopy images taken during fracture treatment and the number saved and sent to the radiologist were collected in a prospective and blinded manner. In 500 consecutive cases, 89% of radiologist reports were not available until after the end of the procedure. There was no discrepancy between the surgeon-dictated operative report on use of fluoroscopy and the radiologist's interpretation of the fluoroscopic images. Three (0.6%) patients had an unexpected finding on the radiologist's report but that did not change the fracture treatment. The mean charge by the radiologist was $166.96±11.84 and the mean reimbursement was $5.83±7.01. For the prospective arm of the study, 41.9% of all intraoperative fluoroscopy images taken were saved and sent to the radiologist. For the majority of procedures, the radiologist report was not available until after the end of the procedure. The radiologist's interpretation of intraoperative fluoroscopy did not alter fracture treatment in any patient. Because of limited benefit and low reimbursement, this study suggests that the practice of having a radiologist interpret intraoperative fluoroscopy during fracture treatment adds little value to patient care. Decision Analysis Level II.

Comparative Study of W-Shaped Angular Plate and Reconstruction Plate in Treating Posterior Wall Fractures of the Acetabulum

ObjectiveThis study aims to assess the medium-term results of the reconstruction of posterior wall fractures using a W-shaped acetabular angular plate (WAAP) compared to those fixed using a reconstruction plate.MethodsBetween July 2006 and March 2009, we performed a retrospective study, which collected data for any patient treated for a posterior acetabular wall fracture. At the time of treatment, patients were either treated using a WAAP or a pelvic reconstruction plate. The intraoperative fluoroscopic images for both groups were compared. The quality of reduction and radiological grading were assessed according to the criteria developed by Matta. The clinical assessment was based on a modified Merle d’Aubigne and Postel scoring.Results53 patients met the inclusion criteria and were followed up for an average of 38 months. 25 patients were treated with a WAAP (study group), and 28 patients were treated with a pelvic reconstruction plate (control group). The intraoperative fluoroscopic images of the study group confirmed extra-articular screw placement in all cases. In the control group, intra-articular screw placement was observed intraoperatively in 5 patients (17.86%), and the definitive location of the periarticular hardware could not be determined in 4 patients (14.29%) during the operation. The differences between the two groups were statistically significant (p = 0.002). In contrast, the quality of fracture reduction, clinical outcomes, and radiological grading in the study group were not significantly different from those of the control group (p>0.05). The radiographic grade was strongly associated with the clinical outcomes in both the study and control groups (p<0.05).ConclusionReconstruction of posterior wall fractures of the acetabulum using a WAAP can help avoid screw penetration of the hip joint, provide a stable fixation of the posterior wall, and ensure good clinical outcomes.

Computer-assisted bone tumour ablation using sparse radiographs

Percutaneous radiofrequency ablation (RFA) is a minimally invasive technique increasingly employed in the treatment of unresectable bone tumours due to its safety, less invasiveness, reduced complications, effectiveness, and predictability. This paper investigates a new pipeline of computer-assisted interventional system with navigation and planning functions for percutaneous RFA as an useful tool to improve clinicians’ performance. Unlike traditional open procedures, percutaneous RFA requires image guidance because a direct visual field of surgical targets is unavailable. Radiographic imaging can be used intra-operatively for navigation, but it generates radiation exposure to patients and clinicians. To reduce the risk of radiation exposure and enhance the performance in computer-assisted bone tumor RFA, this paper addressed two key problems: (1) statistical atlas is employed to construct a global navigation map by deformable registration using a minimal number of intra-operative fluoroscopic images to localize the tumor and (2) a multiple-objective optimization for treatment planning of large tumor RFA is proposed to obtain optimal trajectories and ablation coverage by considering clinical constraints. The proposed system was validated by experiments, showing that the construction error of patient-specific model was 0.84 mm in terms of surface-to-surface distance measure and the optimal planning achieved 100% tumor coverage under multiple clinical constraints.

Improved screw placement for slipped capital femoral epiphysis (SCFE) using robotically-assisted drill guidance.

Slipped Capital Femoral Epiphysis (SCFE) is a common hip displacement condition in adolescents. In the standard treatment, the surgeon uses intra-operative fluoroscopic imaging to plan the screw placement and the drill trajectory. The accuracy, duration, and efficacy of this procedure are highly dependent on surgeon skill. Longer procedure times result in higher radiation dose, to both patient and surgeon. A robotic system to guide the drill trajectory might help to reduce screw placement errors and procedure time by reducing the number of passes and confirmatory fluoroscopic images needed to verify accurate positioning of the drill guide along a planned trajectory. Therefore, with the long-term goals of improving screw placement accuracy, reducing procedure time and intra-operative radiation dose, our group is developing an image-guided robotic surgical system to assist a surgeon with pre-operative path planning and intra-operative drill guide placement.

Radiographic Landmarks for Locating the Femoral Origin of the Superficial Medial Collateral Ligament

Background: Little has been written about the use of radiographic landmarks for locating the origin of the superficial medial collateral ligament (sMCL). A standardized radiographic landmark for the sMCL origin using intraoperative fluoroscopic imaging may be of value in aiding the surgeon in accurate femoral tunnel placement in the setting of extensive soft tissue disruption and bony attrition. Purpose: To determine a reproducible radiographic landmark that will assist in correct femoral tunnel placement in sMCL repair and reconstruction. Study Design: Descriptive laboratory study. Methods: Ten fresh-frozen unmatched human cadaveric knees were dissected, and the origin of the sMCL was exposed. A 2-mm metallic marker was then placed at the center of the femoral origin of the sMCL. True lateral fluoroscopically assisted digital radiographs were obtained of the knee with the posterior and distal femoral condyles overlapping in a standardized fashion. With the use of computer software, reference lines were drawn on the images, creating 4 quadrants. Two independent examiners performed quantitative measurements of the sMCL origin in relation to this axis and to the Blumensaat line. Results: Mean measurements showed the sMCL origin to be closely related to the intersection point of the Blumensaat line and a line drawn distally from the posterior femoral cortex on a true lateral radiograph. The sMCL origin was found at a mean point 1.6 ± 4.3 mm posterior and 4.9 ± 2.1 mm proximal to the intersection of a line paralleling the posterior femoral cortex and a line drawn perpendicular to the posterior femoral cortical line, where it intersects the Blumensaat line. In 5 of 10 specimens, the center of the sMCL origin fell precisely on the Blumensaat line. The remaining specimens had sMCL origins anterior to the Blumensaat line. The femoral origin of the sMCL was found in the proximal and posterior quadrants in 8 of 10 specimens. Conclusion: With a relatively small amount of deviation, the sMCL origin can be consistently identified on a true lateral radiograph of the knee using reproducible reference lines on fluoroscopic imaging. Clinical Relevance: Accurate identification of the femoral origin of the sMCL can be accomplished by intraoperative fluoroscopic imaging. This information may be of significant benefit in repairing acute injuries and in reconstructive procedures complicated by bony attrition and soft tissue loss.

Recovery Room Radiographs Not Found to Have Incremental Utility Above Intraoperative Images After Lumbar Fusion Procedures

Retrospective case series. To characterize the clinical utility of imaging in the recovery room after lumbar fusion procedures. Two sets of images are commonly obtained at the end of lumbar fusion procedures: intraoperative fluoroscopic images near the time of wound closure and plain film images after the procedure in the recovery room. The latter may have low clinical utility. We identified a consecutive series of lumbar fusion procedures. A panel of 3 reviewers assessed intraoperative and recovery room series both for radiographical adequacy and for issues with the surgical construct. One hundred ninety cases were reviewed, of which 92 were posterolateral lumbar fusions, 42 were anterior lumbar interbody fusions, 24 were transforaminal lumbar interbody fusions, and 32 were anterior-posterior fusions. All intraoperative series were adequate, whereas only 90% of recovery room series were adequate. Recovery room series had visible issues with construct placement in 4 cases. In each of these cases, however, the issue was also clearly visible on the intraoperative series, was found to be acceptable clinically, and did not alter management in any way. This study demonstrates that recovery room images are inferior to intraoperative images and offer little or no incremental clinical utility for detecting issues with surgical constructs after lumbar fusion procedures. In settings where it is still performed, recovery room imaging might be discontinued to realize savings in cost, radiation exposure, and time. 4.

Inadequate ‘three-point’ proximal fixation predicts failure of the Gamma nail

The Gamma nail is frequently used in unstable peri-trochanteric hip fractures. We hypothesised that mechanical failure of the Gamma nail was associated with inadequate proximal three-point fixation. We identified a consecutive series of 299 Gamma nails implanted in 299 patients over a five-year period, 223 of whom fulfilled our inclusion criteria for investigation. The series included 61 men and 162 women with a mean age of 81 years (20 to 101). Their fractures were classified according to the Modified Evans' classification and the quality of fracture reduction was graded. The technical adequacy of three points of proximal fixation was recorded from intra-operative fluoroscopic images, and technical inadequacy for each point was defined. All patients were followed to final follow-up and mechanical failures were identified. A multivariate statistical analysis was performed, adjusting for confounders. A total of 16 failures (7.2%) were identified. The position of the lag screw relative to the lateral cortex was the most important point of proximal fixation, and when inadequate the failure rate was 25.8% (eight of 31: odds ratio 7.5 (95% confidence interval 2.5 to 22.7), p < 0.001). Mechanical failure of the Gamma nail in peri-trochanteric femoral fractures is rare (< 1%) when three-point proximal fixation is achieved. However, when proximal fixation is inadequate, failure rates increase. The strongest predictor of failure is positioning the lateral end of the lag screw short of the lateral cortex. Adherence to simple technical points minimises the risk of fixation failure in this vulnerable patient group.

Intraoperative panoramic image using alignment grid, is it accurate?

Minimally invasive orthopedic trauma surgery relies heavily on intraoperative fluoroscopic images to evaluate the quality of fracture reduction and fixation. However, fluoroscopic images have a narrow field of view and often cannot visualize the entire long bone axis. To compare the coronal femoral alignment between conventional X-rays to that achieved with a new method of acquiring a panoramic intraoperative image. Twenty-four cadaveric femurs with simple diaphyseal fractures were fixed with an angulated broad DCP to create coronal plane malalignment. An intraoperative alignment grid was used to help stitch different fluoroscopic images together to produce a panoramic image. A conventional X-ray of the entire femur was then performed. The coronal plane angulation in the panoramic images was then compared to the conventional X-rays using a Wilcoxon signed rank test. The mean angle measured from the panoramic view was 173.9° (range 169.3°-178.0°) with median of 173.2°. The mean angle measured from the conventional X-ray was 173.4° (range 167.7°-178.7°) with a median angle of 173.5°. There was no significant difference between both methods of measurement (P = 0.48). Panoramic images produced by stitching fluoroscopic images together with help of an alignment grid demonstrated the same accuracy at evaluating the coronal plane alignment of femur fractures as conventional X-rays.

Comment on Xu et al.: A retrospective study of posterior malleolus fractures

Dear Sir, This retrospective study regarding the factors affecting the surgical outcome of posterior malleolus fractures by Xu et al. [1] has really interested us. It provides a commendable and exhaustive analysis of the all the possible factors which might have a say in the outcome of these injuries. However, the article does not provide guidance on whether fractures of the posterior malleolus less than 25 % in size should be fixed or not since the results have been depicted to be equivocal in both the scenarios. However we would like to share a technical trick which in our opinion guides the fixation of a posterior malleolus fragment if smaller in size. After fixation of medial and lateral malleoli, we routinely perform tests to evaluate the stability of the ankle. Tests evaluating the inferior tibiofibular syndesmotic injury as well the antero-posterior instability of the tibia-talar articulation are performed and the joint viewed fluoroscopically. The latter is the guide to treatment of such injuries in our view, particularly if the fragment size is smaller than 25 % of the articular surface and does not ‘merit’ fixation on conventional grounds [2, 3]. If the intraoperative fluoroscopic images demonstrate instability while performing the anterior and posterior drawer tests, it is advisable to fix the posterior malleolus fragment even if the fragment is too small. This is because the residual translational instability has the potential to cause arthritis even in the absence of articular surface unevenness. Presented are the images of a 23-year-old male demonstrating a positive drawer test with a tiny posterior malleolus fragment (Fig. 1). The stability improved remarkably after fixation of the fragment (Fig. 2). Fig. 1 Intraoperative fluoroscopic lateral views of the ankle showing marked instability upon performing the ankle drawer test Fig. 2 After fixation of the small posterior malleolus fragment showing distinctly improved stability We suggest this step should be incorporated consistently for decision making in posterior malleolus fractures having a smaller size of <25 % for achieving a better outcome of such injuries.

Varus External Rotation Stress Test for Radiographic Detection of Deep Deltoid Ligament Disruption With and Without Syndesmotic Disruption

External rotation stress is used intraoperatively for diagnosing medial ankle and syndesmotic instability in rotational ankle fractures after reduction and fixation of the fibula. However, external rotation includes hindfoot, midfoot, and ankle motion. The purpose of this study was to determine the effect of hindfoot positioning when using the external rotation stress test. Isolated deep deltoid ligament (DDL) instability and combined DDL and syndesmotic instability were modeled. An intact fibula was used as a surrogate for an anatomically fixed fibula fracture. Six cadaver specimens with full-length tib-fib articulations were used. Specimens were fixed into a Taylor Spatial Frame (Smith&Nephew, Memphis, TN) with 4 to 5 points of fixation in the tibia and the foot. Specimens were mounted in ankle and foot neutral position. Metal markers were placed at the medial gutter and syndesmosis. Anteroposterior (AP) and mortise radiographs were obtained in 3 positions: neutral hindfoot, valgus external rotation stress, and varus external rotation stress. For both valgus and varus external rotation stress, the frame was loosened and stressed to a hard end point and then locked. Three modes were studied: intact ligaments, DDL transected, and DDL+ syndesmosis transected. Digital radiographs were used to measure the displacement of the markers. The varus external rotation stress test demonstrated significant widening of the medial gutter in specimens with isolated DDL instability, in both AP (P = .01) and mortise (P = .02) views. Both maneuvers demonstrated significant medial gutter widening with combined DDL and syndesmosis disruption (P ≤ .01), although the varus external rotation stress test produced nearly twice as much displacement (10.7 vs 5.4 mm). Syndesmotic widening was not significant with either maneuver. Varus external rotation stress was more effective than valgus external rotation stress in demonstrating displacement of markers at the medial gutter and on AP and mortise radiographs for both DDL and DDL with syndesmotic instability. These findings may lead to improved clinical detection of rotational ankle instability from combined DDL and syndesmotic disruption, which may affect decision making for using syndesmotic fixation when using intraoperative stress fluoroscopy images. Occult DDL instability may be underdiagnosed, and this may affect future directions of the treatment of rotational ankle fractures and severe sprains.

Arthrogram-assisted Fixation of Slipped Capital Femoral Epiphysis

Intraoperative fluoroscopy does not always provide the operating surgeon with optimal visualization of a slipped capital femoral epiphysis (SCFE). Arthrography can be used to enhance fluoroscopic images of these patients. This study retrospectively compared the screw placement between patients who received conventional versus arthrographic-assisted in situ screw fixation for SCFE. We reviewed the charts and radiographs of all patients diagnosed with a SCFE at our institution from 2005 to 2010. We isolated those who received postoperative computed tomography (CT) scans to confirm screw placement, and subdivided the patients into 2 groups: those who received arthrograms to facilitate screw placement and those who did not. The screw-tip-to-articular-surface distance was then measured on intraoperative fluoroscopic images and postoperative CT scans. Seventy-eight patients met inclusion criteria and 24 received an intraoperative arthrogram. Screw placement determined by intraoperative fluoroscopic images did not differ between the 2 groups. When measured on postoperative CT scans the screw-tip-to-articular-surface distance was significantly smaller in the arthrogram-assisted cohort (2.8 vs. 5.2 mm), and the difference between intraoperative and postoperative measurements was significantly greater in the arthrogram-assisted cohort (4.9 vs. 1.6 mm). No cases of intra-articular screw placement were found in either cohort, nor were there any cases demonstrating loss of fixation. Arthrogram-assisted fixation of SCFE is a safe and effective tool in patients whose body habitus makes diagnostic fluoroscopic images difficult to obtain. It is, however, not without technical challenges. After the dye is injected it becomes more difficult to visualize the subchondral bone on fluoroscopic images. Our screws were, on average, 4.9 mm closer to the joint space on CT scans than seen intraoperatively. The operating surgeon must be aware of this fact to avoid joint penetration. Level III.

Postoperative Radiographs After Pinning of Supracondylar Humerus Fractures

The purpose of this study was to evaluate the necessity of early postoperative radiographs after pinning of supracondylar humerus fractures by determining both the percentage of patients who displayed change in fracture fixation and whether these changes affected their outcome. A series of 643 consecutive patients who underwent operative management of Gartland type II and III fractures at our institution between January 2002 and December 2010 were reviewed. Demographic data were obtained through chart review, including age, sex, extremity, fracture type, and mechanism. Intraoperative fluoroscopic images were compared with postoperative radiographs to identify changes in fracture alignment and pin placement. A total of 643 patients (320 females, 323 males) with a mean age of 6.1 years (range, 1.1 to 16.0) were reviewed. Fifty-seven percent of fractures were classified as type II and 43% were type III. The overall complication rate was 8.8% (57/643). Pin backout or fracture translation was seen in 32 patients (4.9%) at the first postoperative visit. All of these patients sustained type III fractures. One of these patients required further operative management. Patients with changes in pin or fracture alignment did not demonstrate a statistically significant difference in time to first postoperative visit (P=0.23), days to pin removal (P=0.07), or average follow-up time (P=0.10). Fracture severity did not correlate with change in alignment (P=0.952). No postoperative neurological complications were observed in patients with alignment changes. Mild alignment changes and pin migration observed in postoperative radiographs after pinning of supracondylar humerus fractures have little effect on clinical management parameters or long-term sequelae. Radiographs can therefore be deferred until the time of pin removal provided adequate intraoperative stability was obtained. Level IV.