Anna N. Miller

Direct visualization for syndesmotic stabilization of ankle fractures.

Background: Ankle fractures with syndesmotic injury treated via standard trans-syndesmotic fixation have a high percentage of syndesmotic malreduction. 10 We established a protocol involving both direct syndesmosis visualization and meticulous tibial incisura reconstruction via the posterior malleolus fracture fragment, when present, via the attached, intact PITFL, then compared this with historic controls to assess improvement after this type of syndesmosis reconstruction. Materials and Methods: One hundred forty-nine consecutive direct visualization patients were treated prospectively with either open posterior malleolus reduction and fixation, regardless of fragment size (“PM”: 38 patients), or, with no posterior malleolar fracture, open fixation with locked syndesmotic screws (“S”: 97 patients); fracture-dislocations combined both fixation types (“C”: 16 patients). The syndesmosis was opened and debrided in all. All patients had preoperative MRI and postoperative CT. Distances between the fibula and anterior and posterior incisura facets were measured on axial CT. An incongruent joint was defined as an A-P difference greater than 2 mm. Our historic controls were 25 patients previously fixed via indirect, fluoroscopic reduction and syndesmotic screws. Results: In the direct visualization group, 24 ankles (16%) had incongruity, compared with 13 controls (52%). The average difference between anterior and posterior colliculi measurements between PM and C was significant (p = 0.017). Conclusion: Malreductions were significantly decreased in the direct visualization group. However, our reduction sometimes remains imprecise, even with direct visualization and attention to detail. Also, posterior malleolar reconstruction was more accurate than syndesmotic screw fixation in our study.

Variations in sacral morphology and implications for iliosacral screw fixation.

Abstract Posterior pelvic percutaneous fixation following either closed or open reduction is a popular procedure. Knowledge of the posterior pelvic anatomy, its variations, and related imaging is critical to performing reproducibly safe surgery. The dysmorphic sacrum has several key characteristics. The upper portion of the sacrum is relatively colinear with the iliac crests on the outlet radiographic view. Other characteristics include the presence of mammillary bodies (ie, underdeveloped transverse processes) at the sacral mid‐alar area, anterior upper sacral foramina that are not circular, residual upper sacral disks, an acute alar slope oriented from cranial‐posterior‐central to caudal‐anterior‐lateral on the outlet and lateral views of the sacrum, a tongue‐in‐groove sacroiliac joint surface visualized on CT, and cortical indentation of the anterior ala on the inlet radiographic view. The surgeon must be knowledgeable about individual patient anatomy to ensure safe iliosacral screw placement.

Iatrogenic Syndesmosis Malreduction via Clamp and Screw Placement

Objectives: The purpose of this study was to assess the impact of variations in angulation of clamp placement to hold syndesmotic reduction and how subsequent syndesmotic screw placement affects malreduction of the syndesmosis. We hypothesized that an anatomic syndesmosis reduction cannot be reliably achieved with a clamp alone; and, inaccurate placement of intraoperative clamps and trans-syndesmotic screws after reduction can malreduce the ankle syndesmosis. Methods: After computed tomography scanning of the intact limbs, 14 cadaver legs were dissected; the syndesmosis was completely disrupted in all. Using planned drill holes, clamps were first placed at 0°, 15°, and 30° angles from the fibula, then separate posterolateral, followed by lateral, screws were placed. After each intervention, the limb had a computed tomography scan so the fibular reduction could be evaluated precisely. Results: Clamps placed at 15° and 30° significantly displaced the fibula in external rotation and caused significant overcompression of the syndesmosis. Thirty-degree lateral screws caused significant anteromedial displacement, external rotation, and overcompression of the syndesmosis. The 15° posterolateral screws also caused significant external rotation and overcompression of the syndesmosis. Conclusions: Our study demonstrates that intraoperative clamping and fixation can cause statistically significant malreduction of the syndesmosis. This article should alert clinicians that clamp and screw placement can cause iatrogenic malreduction of the syndesmosis and make them aware that these dangers occur with specific clamp and screw angles in particular.

Management of humeral shaft fractures.

&NA; Humeral shaft fractures account for approximately 3% of all fractures. Nonsurgical management of humeral shaft fractures with functional bracing gained popularity in the 1970s, and this method is arguably the standard of care for these fractures. Still, surgical management is indicated in certain situations, including polytraumatic injuries, open fractures, vascular injury, ipsilateral articular fractures, floating elbow injuries, and fractures that fail nonsurgical management. Surgical options include external fixation, open reduction and internal fixation, minimally invasive percutaneous osteosynthesis, and antegrade or retrograde intramedullary nailing. Each of these techniques has advantages and disadvantages, and the rate of fracture union may vary based on the technique used. A relatively high incidence of radial nerve injury has been associated with surgical management of humeral shaft fractures. However, good surgical outcomes can be achieved with proper patient selection.

Assessment of vascularity of the femoral head using gadolinium (Gd-DTPA)-enhanced magnetic resonance imaging: A CADAVER STUDY

In spite of extensive accounts describing the blood supply to the femoral head, the prediction of avascular necrosis is elusive. Current opinion emphasises the contributions of the superior retinacular artery but may not explain the clinical outcome in many situations, including intramedullary nailing of the femur and resurfacing of the hip. We considered that significant additional contribution to the vascularity of the femoral head may exist. A total of 14 fresh-frozen hips were dissected and the medial circumflex femoral artery was cannulated in the femoral triangle. On the test side, this vessel was ligated, with the femoral head receiving its blood supply from the inferior vincular artery alone. Gadolinium contrast-enhanced MRI was then performed simultaneously on both control and test specimens. Polyurethane was injected, and gross dissection of the specimens was performed to confirm the extraosseous anatomy and the injection of contrast. The inferior vincular artery was found in every specimen and had a significant contribution to the vascularity of the femoral head. The head was divided into four quadrants: medial (0), superior (1), lateral (2) and inferior (3). In our study specimens the inferior vincular artery contributed a mean of 56% (25% to 90%) of blood flow in quadrant 0, 34% (14% to 80%) of quadrant 1, 37% (18% to 48%) of quadrant 2 and 68% (20% to 98%) in quadrant 3. Extensive intra-osseous anastomoses existed between the superior retinacular arteries, the inferior vincular artery and the subfoveal plexus.

Operative Treatment of Acetabular Fractures in an Older Population Through a Limited Ilioinguinal Approach

Objectives: To compare treatment of acetabular fractures in elderly patients through a limited approach versus a standard ilioinguinal approach and assess changes in outcome and morbidity. Design: Retrospective cohort comparison analysis. Setting: Tertiary referral center. Patients/Participants: Between January 1992 and January 2006, 143 patients 55 years of age or older were treated for acetabular fractures. Of these, 41 were treated through either a traditional or limited ilioinguinal approach. Patients with unilateral surgeries and a minimum follow-up of 2 years were included. Intervention: Open reduction and internal fixation of acetabular fractures through a limited (lateral two windows) approach versus traditional three window ilioinguinal approach. Outcome measures: Radiographic assessment of healing, reduction quality, progression to arthritis and total hip arthroplasty, operative time, length of stay, complications, SF-36, Musculoskeletal Functional Assessment, and the Short Musculoskeletal Functional Assessment. Results: The two groups were equivalent in terms of preinjury comorbidities, mechanism of injury, type and severity of fracture pattern, time to surgery, length of hospitalization, and incidence of postoperative complications. The overall rate of secondary total hip arthroplasty was 26.8% and was equivalent between the two groups. Functional outcome scores were comparable. The use of the lateral two windows was associated with a significant reduction in both blood loss and operative time. Conclusions: The limited ilioinguinal approach to certain fracture patterns commonly seen in the elderly was associated with a decreased blood loss and surgical time. Moreover, there was no negative impact on outcomes in our cohort. The benefits of decreased blood loss and shorter operative time have a potential positive impact on management of these injuries. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Arterial anatomy of the talus: a cadaver and gadolinium-enhanced MRI study.

Background: Avascular necrosis following a fracture of the talar neck may be secondary to the injury itself, or may result from the surgical approach and exposure during treatment. We sought to define the arterial anatomy of the talus using gadolinium-enhanced magnetic resonance imaging (MRI) and through gross dissection following latex injection of cadaver limbs. The use of gadolinium-enhanced MRI for the evaluation of the arterial supply of the talus has not been previously reported. Methods and Materials: We utilized 12 fresh frozen cadaver limbs to study the arterial anatomy of the talus. The anterior tibial, posterior tibial, and peroneal arteries were isolated and cannulated with polyethylene catheters. Gadolinium was injected into the cannulas, and conventional MRI sequences including suppressed and unsuppressed 3D gradient echo sequences obtained. Following MRI, latex was injected into the cannulas and gross dissection performed. In addition, the vascular constraints to anteromedial and anterolateral approaches to the talus were defined. Results: MRI proved useful in the present study to confirm the presence of specific arterial branches in situ, as well as to demonstrate the rich anastomotic network in and around the talus. A branch to the medial talar neck that has not been previously identified is described which was found in nine of the specimens. This newly described branch to the medial talar neck was consistently noted to be lacerated following a standard anteromedial approach to the talus. Conclusion: The use of gadolinium-enhanced MRI provided very detailed images demonstrating a rich and complex anastomotic arterial network that surrounds and perforates the talus. Clinical Relevance: A thorough understanding of the anatomy and meticulous dissection are essential to prevent unnecessary further injury to the vasculature when treating fractures of the talus.

The Effect of the Shoe-Surface Interface in the Development of Anterior Cruciate Ligament Strain

The shoe-surface interface has been implicated as a possible risk factor for anterior cruciate ligament (ACL) injuries. The purpose of this study is to develop a biomechanical, cadaveric model to evaluate the effect of various shoe-surface interfaces on ACL strain. There will be a significant difference in ACL strain between different shoe-surface combinations when a standardized rotational moment (a simulated cutting movement) is applied to an axially loaded lower extremity. The study design was a controlled laboratory study. Eight fresh-frozen cadaveric lower extremities were thawed and the femurs were potted with the knee in 30 deg of flexion. Each specimen was placed in a custom-made testing apparatus, which allowed axial loading and tibial rotation but prevented femoral rotation. For each specimen, a 500 N axial load and a 1.5 Nm internal rotation moment were placed for four different shoe-surface combinations: group I (AstroTurf-turf shoes), group II (modern playing turf-turf shoes), group III (modern playing turf-cleats), and group IV (natural grass-cleats). Maximum strain, initial axial force and moment, and maximum axial force and moment were calculated by a strain gauge and a six component force plate. The preliminary trials confirmed a linear relationship between strain and both the moment and the axial force for our testing configuration. In the experimental trials, the average maximum strain was 3.90, 3.19, 3.14, and 2.16 for groups I-IV, respectively. Group IV had significantly less maximum strain (p<0.05) than each of the other groups. This model can reproducibly create a detectable strain in the anteromedial bundle of the ACL in response to a given axial load and internal rotation moment. Within the elastic range of the stress-strain curve, the natural grass and cleat combination produced less strain in the ACL than the other combinations. The favorable biomechanical properties of the cleat-grass interface may result in fewer noncontact ACL injuries.

Quantitative Assessment of the Vascularity of the Talus with Gadolinium-enhanced Magnetic Resonance Imaging

BACKGROUND The purpose of this study was to quantify the various arterial contributions to the talus with use of magnetic resonance imaging (MRI). METHODS The arterial anatomy of the talus was studied in ten pairs of fresh-frozen cadaver limbs with use of gadolinium-enhanced MRI in addition to gross dissection following latex injection. MRI proved useful to confirm the presence of specific arterial branches in situ as well as to demonstrate the rich anastomosis network in and around the talus. We further examined the MRI studies to delineate the quantitative contribution of each of the three main arteries to the talus and to each quadrant of the talus (anteromedial [0], anterolateral [1], posterolateral [2], and posteromedial [3]). RESULTS The peroneal artery contributed 16.9% of the blood supply to the talus; the anterior tibial artery, 36.2%; and the posterior tibial artery, 47.0%. The contribution of the anterior tibial artery was greatest in quadrant 0, whereas the contribution of the posterior tibial artery was greatest in quadrants 1, 2, and 3. The peroneal artery did not make the greatest contribution in any quadrant. CONCLUSIONS In contrast to the findings in previous studies, we found that a substantial portion of the talar blood supply can enter posteriorly, which helps to explain why all talar neck fractures do not result in osteonecrosis. This finding, along with a very rich and redundant intraosseous pattern of anastomosis with contributions from all three vessels in each quadrant of the talus, may explain the low occurrence of osteonecrosis in association with talar neck fractures.

Bone Transport for Postinfectious Segmental Tibial Bone Defects With a Combined Ilizarov/Taylor Spatial Frame Technique

Objective: To assess and compare the results of trifocal (two-level bone lengthening with compression at the nonunion site) and bifocal (one-level bone lengthening with compression at the nonunion site) bone transport using the Taylor Spatial Frame (TSF; Smith and Nephew, Inc, Memphis, TN) for postinfectious segmental tibial bone defects. Design: Retrospective study of 12 patients with atrophic tibial nonunions. These patients were treated with resection of the nonunion followed by bone transport using the TSF for the segmental tibial bone defects. All patients were treated by the same surgeon (F.S.). Setting: Level I trauma center. Patients/Participants: Twelve consecutive patients treated for postinfectious segmental tibial bone defects between November 2004 and September 2007. Intervention: All patients were treated using the TSF for a trifocal or bifocal technique of bone transport along with associated soft tissue reconstructive surgeries. All patients were additionally treated with 45 days of culture-specific antibiotics. Outcome Measurement: All patients were evaluated by the guidelines of the Association for the Study of the Method of Ilizarov. Results and Conclusion: All patients achieved complete union and eradication of infection. The results were evaluated according to Association for the Study of the Method of Ilizarov criteria: 83% were excellent and 17% were good in terms of bony outcomes; functional results were excellent in 50%, good in 42%, and fair in 8%. Combined Ilizarov/TSF trifocal and bifocal techniques for the treatment of segmental tibial bone defects achieve union without malalignment of the mechanical axis.