Definitive internal fracture fixation followed by staged free flap coverage ("fix followed by flap" protocol) for open Gustilo type IIIB fractures.

BACKGROUND: Although the concept of the "fix and flap" approach, in which definitive fracture fixation and flap coverage are completed in a single procedure at the earliest opportunity may seem ideal for the treatment of Gustilo type IIIB open fractures, the individual circumstances of patients, such as polytrauma or multiple fracture cases may not allow for the immediate fracture fixation and flap coverage ("fix and flap" approach). In our hospital, patients with Gustilo type IIIB open fractures are treated with definitive internal fixation of the fracture followed by staged flap coverage ("fix followed by flap" protocol) when the "fix and flap" approach was not feasible due to the patient's condition or difficulty in coordinating surgery schedules. The "fix followed by flap" protocol provides benefits in terms of flexibility in adjusting the surgical timetable, simplifying the planning of flap coverage following fracture fixation, and minimizing individual surgical invasion. METHODS: We reviewed 10 cases of severe open fractures treated with the "fix followed by flap" protocol and evaluated their outcomes. All surgical procedures, including wound debridement, fracture fixation, and flap coverage, were performed by orthoplastic surgeons specializing in both fracture surgery and microsurgery including soft tissue reconstruction. RESULTS: All free flaps survived, and no partial necrosis was observed. None of the patients developed postoperative deep infection up to the last follow-up. Fracture union was achieved in all patients with or without autologous bone grafts. The median time for union was 9.4 months (range, 4-12 months). CONCLUSIONS: This study presents favorable outcomes of treatment for Gustilo type IIIB open fractures with fracture fixation followed by staged flap coverage ("fix followed by flap" protocol). Despite a delay in flap coverage, the consistency of treatment provided by orthoplastic surgeons may have contributed to the favorable outcomes in this study.

Characteristics and comparative study of thoracolumbar spine injury and dislocation fracture due to tertiary trauma.

PURPOSE: Thoracolumbar spine injury is frequently seen with high-energy trauma but dislocation fractures are relatively rare in spinal trauma, which is often neurologically severe and requires urgent treatment. Therefore, it is essential to understand other concomitant injuries when treating dislocation fractures. The purpose of this study is to determine the differences in clinical features between thoracolumbar spine injury without dislocation and thoracolumbar dislocation fracture. METHODS: We conducted an observational study using the Japan Trauma Data Bank (2004-2019). A total of 734 dislocation fractures (Type C) and 32,382 thoracolumbar spine injuries without dislocation (Non-type C) were included in the study. The patient background, injury mechanism, and major complications in both groups were compared. In addition, multivariate analysis of predictors of the diagnosis of dislocation fracture using logistic regression analysis were performed. RESULTS: Items significantly more frequent in Type C than in Non-type C were males, hypotension, bradycardia, percentage of complete paralysis, falling objects, pincer pressure, accidents during sports, and thoracic artery injury (P < 0.001); items significantly more frequent in Non-type C than in Type C were falls and traffic accidents, head injury, and pelvic trauma (P < 0.001). Logistic regression analysis showed that younger age, male, complete paralysis, bradycardia, and hypotension were associated with dislocation fracture. CONCLUSION: Five associated factors were identified in the development of thoracolumbar dislocation fractures. LEVEL OF EVIDENCE: III.

Biomechanics of callus in the bone healing process, determined by specimen-specific finite element analysis.

As fractures heal, immature callus formed in the hematoma is calcified by osteoblasts and altered to mature bone. Although the bone strength in the fracture-healing process cannot be objectively measured in clinical settings, bone strength can be predicted by specimen-specific finite element modeling (FEM) of quantitative computed tomography (qCT) scans. FEM predictions of callus strength would enable an objective treatment plan. The present study establishes an equation that converts material properties to bone density and proposes a specimen-specific FEM. In 10 male New Zealand white rabbits, a 10-mm long bone defect was created in the center of the femur and fixed by an external fixator. The callus formed in the defect was extracted after 3-6 weeks, and formed into a (5 × 5 × 5 mm3) cube. The bone density measured by qCT was related to the Young's modulus and the yield stress measured with a mechanical tester. For validation, a 10-mm long bone defect was created in the central femurs of another six New Zealand white rabbits, and fixed by an external fixator. At 3, 4, and 5 weeks, the femur was removed and subjected to Computed tomography (CT) scanning and mechanical testing. A specimen-specific finite element model was created from the CT data. Finally, the bone strength was measured and compared with the experimental value. The bone mineral density σ was significantly and nonlinearly correlated with both the Young's modulus E and the yield stress σ. The material-property conversion equations were E = 0.2391e8.00ρ and ρ = 30.49σ2.41. Moreover, the experimental bone strength was significantly linearly correlated with the prospective FEM. We demonstrated the Young's moduli and yield stresses for different bone densities, enabling a FEM of the bone-healing process. An FEM based on these material properties is expected to yield objective clinical judgment criteria.

A1 pulley stretching treats trigger finger: A1 pulley luminal region under digital flexor tendon traction.

BACKGROUND: A1 pulley stretching is recognized as a clinically beneficial treatment for trigger finger. It is thought to lead to an increase in the cross-sectional area of the A1 pulley luminal region, thus improving trigger finger symptoms. The purpose of the present study was thus to evaluate the resultant forces during stretching that increase the CSA of the A1 pulley luminal region using fresh-frozen cadavers. METHODS: Using seven fingers from three fresh-frozen cadavers to replicate A1 pulley stretching, we investigated the resultant forces during stretching that increase the cross-sectional area of the A1 pulley luminal region. The traction forces of the flexor digitorum profundus tendons were increased in steps to 150 N, and the cross-sectional area and height of the A1 pulley luminal region were measured using ultrasonography. FINDINGS: The cross-sectional area of the A1 pulley luminal region increased with step-wise increases in the flexor digitorum profundus traction. On average, the cross-sectional area and height of the A1 pulley luminal region showed increases of 31.4% and 43.6%, respectively, compared to the unloaded condition. INTERPRETATION: These results confirmed that A1 pulley stretching increases the cross-sectional area of the A1 pulley luminal region. A1 pulley stretching has the potential to reduce the severity of trigger finger in patients facing surgery.

Fusion Surgery Required for Recurrent Pediatric Atlantoaxial Rotatory Fixation after Failure of Temporary Fixation with Instrumentation.

In cases of chronic irreducible and recurrent unstable atlantoaxial rotatory fixation (AARF), closed reduction and its maintenance are often unsuccessful, requiring surgical treatment. The purpose of the present report is to describe a rare case of pediatric AARF that required multiple treatments. A 6-year-old boy was diagnosed as having type 2 AARF. After conservative treatment, the patient was treated with temporary fixation surgery (C1-C2 Magerl) without a bone graft in consideration of motion preservation after screw removal. AARF recurred after the screw removal and required fusion surgery (Magerl-Brooks) with an iliac bone graft. Ultimately, bone union was achieved and the screws were removed 11 months after the surgery. We recommend surgeons be cautious when choosing temporary fixation surgery for AARF in small children. Further investigation is needed to determine the optimal time before screw removal.