Fixation strength of anteriorly inserted headless screws for talar neck fractures.

BACKGROUND: For noncomminuted talar neck fractures, traditional fixation is with small fragment screws or cannulated screws. Newer screw systems on the market allow placement of cannulated headless screws, which provide compression by virtue of a variable-pitch thread. The headless construct has an inherent advantage, particularly for the talus, when the screws must be countersunk to prevent wear of the joint articular surfaces. This study tested the biomechanical fixation strength of cannulated headless variable-pitch screws compared with conventional cannulated screws, both placed in an anterior to posterior direction. METHODS: A reproducible talar neck fracture was created in nine paired, preserved, cadaver talar necks using a materials testing machine. Talar head fixation was then performed with two cannulated headless variable-pitch 4/5 screws or two 4.0-mm conventional cannulated screws. The specimens were tested to failure and the fixations were normalized to their intact pairs and compared. RESULTS: The headless variable-pitch screw fixation had significantly lower failure displacement than the conventional screw fixation. No significant differences were found between the two fixations for failure stiffness, load at failure or energy absorbed. CONCLUSIONS: Cannulated headless variable-pitch screws significantly improved failure displacement when compared to conventional cannulated screws in a cadaveric model, and may be a viable option for talus fracture fixation. CLINICAL RELEVANCE: Headless, fully threaded, variable-pitch screws have inherent advantages over conventional screws in that they may be less damaging to the articular surface and can compress the fracture for improved reduction. This study demonstrates these screws are also biomechanically similar to conventional screws.

Is application of an internal anterior pelvic fixator anatomically feasible?

BACKGROUND: Spinal hardware has been adapted for fixation in the setting of anterior pelvic injury. This anterior subcutaneous pelvic fixator consists of pedicle screws placed in the supraacetabular region connected by a contoured connecting rod placed subcutaneously and above the abdominal muscle fascia. QUESTIONS/PURPOSES: We examined the placement of the components for anterior subcutaneous pelvic fixator relative to key vascular, urologic, bony, and surface structures. METHODS: We measured the CT scans of 13 patients after placement of the pelvic fixator to determine the shortest distances between the fixator components and important anatomic structures: the femoral vascular bundle, the urinary bladder, the cranial margin of the hip, the screw insertion point on the bony pelvis, the relationship between the pedicle screw and the corridor of bone in which it resided, and the position relative to the skin. RESULTS: The average distance from the vascular bundle to the pedicle screw was 4.1 cm and 2.2 cm to the connecting rod. The average distance from the connecting rod to the anterior edge of the bladder was 2.6 cm. The average distance from the screw insertion point to the hip was 2.4 cm; none penetrated the hip. The average screw was in bone for 5.9 cm. The pedicle screws were on average 2.1 cm under the skin. The average distance from the anterior skin to the connecting rod was 2.7 cm. CONCLUSIONS: Components of this anterior pelvic fixator are close to important anatomic structures. Careful adherence to the surgical technique should minimize potential risk. LEVEL OF EVIDENCE: Level IV, retrospective study. See Guidelines for Authors for a complete description of levels of evidence.

Open Reduction and Internal Fixation of a Pediatric Talar Body Fracture using a Medial Malleolar Osteotomy - A Case Report.

Introduction: Talus fracture injuries are rare and most literature pertains to fractures in skeletally mature adults. It is unusual for pediatric talus fractures to be treated operatively and is normally treated with immobilization. The location of the talus fracture required a medial malleolar osteotomy to facilitate exposure and reduction, which was fixed with temporary smooth K-wires. The authors were unable to identify a previous description of this technique in the literature. Case Report: An 11-year-old female was referred to our hospital due to polytraumatic injuries sustained in a roll-over MVC. A displaced fracture of the talus body was present. Due to the fracture location, a medial malleolar osteotomy was required for exposure. An open reduction and internal fixation was performed using subchondral minifragment screws under general anesthesia. The patient healed uneventfully, regained a normal gait and full, pain-free range of motion. Conclusions: Medial malleolar osteotomy with smooth K-wire fixation appears to be a safe method for gaining access to the talus when required for reduction and/or fixation of pediatric talus fractures.

Standardized posterior pelvic imaging: use of CT inlet and CT outlet for evaluation and management of pelvic ring injuries.

OBJECTIVES: The null hypothesis of this study states that routine axial computed tomography (CT) images are obtained at a consistent and reproducible orientation relative to the sacrum. The secondary null hypothesis states that there is no difference in the measurement of the safe zone for placement of iliosacral screws when using routine axial CT images and standardized reconstructions in defined planes perpendicular and parallel to the sacrum. DESIGN: Retrospective review. SETTING: University Level 1 Trauma Center. PATIENTS: Sixty-eight consecutive trauma patients evaluated with routine pelvic CT, without pelvic ring injury. INTERVENTION: Retrospective radiographic review and measurement. METHODS: Sixty-eight consecutive adult patients with routine axial pelvic CT scans, without injury to the pelvic ring, and obtained as part of a trauma evaluation were retrospectively identified. The orientation of the axial slices relative to the sacrum was measured for each patient and compared. The maximal cross-sectional distance at the smallest section of the sacral ala (safe zone) was measured using the routine axial CT images, and these measurements were compared with similar measurements taken on standardized images perpendicular (CT inlet) and parallel (CT outlet) to the body of the sacrum. Additional data referencing the orientation of multiple sacral radiographic landmarks were also collected. RESULTS: The orientation of routine axial CT image planes relative to the sacrum spanned a wide range. The angle between the routine axial CT plane and the sacrum varied from 43.5 to 82.0 degrees (SD = 9 degrees). Significant differences were found in measured safe zones of routine axial CT images compared with standardized CT inlet and CT outlet images. Compared with CT inlet images, routine axial CT images underestimated safe zones for transverse sacral screws at both S1 (P < 0.01) and S2 (P < 0.01). When compared with CT outlet images, routine axial CT images overestimated safe zones for oblique sacroiliac screws (P < 0.01) and underestimated the safe zone for S2 transverse sacral style screws (P < 0.01). No significant differences in measured variables were found between genders and sacral morphology. CONCLUSIONS: Our null hypotheses were rejected: routine axial CT images were found to be at widely ranging orientations relative to the sacrum, and standardized CT images (CT inlet and CT outlet) demonstrated statistically significant differences in measurements of safe zones compared with routine axial CT images. Furthermore, the CT inlet and CT outlet views provide additional information regarding sacral landmarks that could be useful for preoperative planning.

Upright versus supine radiographs of clavicle fractures: does positioning matter?

OBJECTIVES: To determine whether clavicle fracture displacement and shortening are different between upright and supine radiographic examinations. DESIGN: Combined retrospective and prospective comparative study. SETTING: Level I Trauma Center. PATIENTS: Forty-six patients (mean age, 49 years; range, 24-89 years) with an acute clavicle fracture were evaluated. INTERVENTION: Standardized clavicle radiographs were obtained in both supine and upright positions for each patient. Displacement and shortening were measured and compared between the 2 positions. MAIN OUTCOMES MEASUREMENTS: One resident and 3 traumatologists classified the fractures and measured displacement and shortening. Data were aggregated and compared to ensure reliability with a 2-way mixed intraclass correlation. RESULTS: Fracture displacement was significantly greater when measured from upright radiographs (15.9 ± 8.9 mm) than from supine radiographs (8.4 ± 6.6 mm, P < 0.001), representing an 89% increase in displacement with upright positioning. Forty-one percent of patients had greater than 100% displacement on upright but not on supine radiographs. Compared with the uninjured side, 3.0 ± 10.7 mm of shortening was noted on upright radiographs and 1.3 ± 9.5 mm of lengthening on supine radiographs (P < 0.001). The intraclass correlation was 0.82 [95% confidence interval (CI), 0.73-0.89] for OTA fracture classification, 0.81 (95% CI, 0.75-0.87) for vertical displacement, and 0.92 (95% CI, 0.88-0.95) for injured clavicle length, demonstrating very high agreement among evaluators. CONCLUSIONS: Increased fracture displacement and shortening was observed on upright compared with supine radiographs. This suggests that upright radiographs may better demonstrate clavicle displacement and predict the position at healing if nonoperative treatment is selected.

Massive desmoplastic fibroblastoma with scapular invasion.

Desmoplastic fibroblastoma is a rare benign tumor usually associated with a favorable outcome. The tumor is characterized by fibroblastic cells that are sparsely distributed in a collagenous and fibromyxoid background. The growth of this tumor is generally indolent, and most tumors are small, subcutaneous lesions. They tend to behave in a nonaggressive manner, and several studies have reported no recurrences even after marginal excision. Invasion and destruction of bone are distinctly uncommon features.This article describes an unusual case of desmoplastic fibroblastoma that presented with a massive 23-cm tumor. The tumor was also unique for its infiltration and destruction of the scapula. The aggressive clinical features prompted the original physicians to administer chemotherapy, but the tumor exhibited no response to systemic treatment. The patient eventually underwent limb-sparing surgery at our hospital, which included en bloc resection, complete scapulectomy, and osteoarticular allograft replacement. The invasiveness of the tumor and its large size are distinctly unusual for desmoplastic fibroblastomas. Following surgical excision, the patient has remained continuously disease free for >5 years, which is in keeping with the intrinsically benign nature of the tumor. This case demonstrates that desmoplastic fibroblastoma can occasionally reach an enormous size and may exhibit invasive characteristics, but this does not necessarily portend subsequent recurrence of disease.