Radial Nerve Paralysis in Diaphyseal Fractures of the Humerus.

One of the most common complications associated with a diaphyseal humeral fracture is the development of a radial nerve injury. We conducted a study to analyze the degree of recovery and prognostic factors associated with radial nerve palsy in patients with diaphyseal humerus fractures. We retrospectively analyzed 28 patients who presented to the Hospital La Fe, Valencia, Spain, with a diaphyseal humerus fracture associated with radial nerve injury between 2010 and 2020. A total of 14.3% (n = 4) of the patients in our cohort had open fractures and 85.7% (n = 24) had closed fractures. There were no statistically significant differences between the type of treatment and the type of fracture (p = .13). There were also no significant differences between the type of treatment and recovery time (p = .42). There was a statistically significant difference (p = .04) in the mean recovery time for patients with preoperative radial nerve injuries (11.9 months) compared with patients who sustained a radial nerve injury secondary to surgical repair of the fracture (8.6 months). The difference in recovery time between patients with open and closed fractures was not statistically significant (p = .3). Results of the study showed that the type of fracture (i.e., open or closed) did not affect radial nerve palsy recovery time. Patients who sustain radial nerve injuries secondary to a surgical repair have a shorter recovery time than patients who sustain primary radial nerve injuries.

Security of 3D-printed polylactide acid piece sterilization in the operating room: a sterility test.

INTRODUCTION: 3D-printing technology has become very popular the last 10 years, and their advantages have been widely proved. However, its safety in the operating room after sterilization has not been evaluated. Thus, the use of 3D printing is still questioned. The aim of this work is to evaluate the security of polylactic acid (PLA) to print surgical models after its sterilization. MATERIALS AND METHODS: One hundred and eighty-six PLA plates and 6 negative controls without microorganisms were seeded. After 10 days of culture, the PLA plates were randomized into three groups: A, B, and C. Group A underwent a sterilization process using an autoclave program at 134 °C. Group B was seeded in different culture media and group C was used to make crystal violet stains on the biofilms formed on the PLA. Mechanical properties of PLA after autoclave sterilization including, the breaking load, deformation and breaking load per surface were calculated. RESULTS: Hundred percent of the group B showed monomicrobial growth. Stains performed on group C PLA showed biofilms in all PLA pieces. After sterilization, no pathogen growth was observed in group A during the culture observation period showing 100% sterilization effectiveness. A filling percentage of 5% obtained a breaking load of 6.36 MPa, and its elastic limit occurred after an elongation of 167.4%. A 10% infill was mechanically safe. CONCLUSIONS: Autoclave sterilization of PLA-printed pieces is safe for the patient and mechanically strong for the surgeon. This is the first 3D-printing protocol described and evaluated to implement 3D-printing technology safely in the operating room. SIGNIFICANCE AND IMPACT OF STUDY: This is the first 3D-printing protocol described to print and sterilize 3D biomodels using an autoclave showing its biological safety and its mechanical resistance.

Autoclave sterilization of an in-house 3D-printed polylactic acid piece: biological safety and heat-induced deformation.

AIMS: Fused filament fabrication 3D printing with polylactic acid filaments is the most widely used method to generate biomodels at hospitals throughout the world. The main limitation of this manufacturing system is related to the biomodels' temperature sensitivity, which all but prevents them to be sterilized using conventional methods. The purpose of this study is to define an autoclave temperature-resistant FFF-PLA 3D printing protocol to print 3D fractures biomodels during preoperative planning. METHODS AND RESULTS: Six different printing protocols were established, each with a different infill percentage. Ten distal radius biomodels were printed with each protocol and each biomodel was subject to 3D scanning. The biomodels were subsequently autoclave-sterilized at 134 °C and subjected to a new scanning process, which was followed by a calculation of changes in area, volume and deformity using the Hausdorff-Besicovitch method. Finally, 192 polylactic acid models were produced using the printing protocol offering the greatest resistance and were contaminated with 31 common nosocomial pathogens to evaluate the effectiveness of sterilizing the model printed using the said protocol. Sterilization resulted in a mean deformation of the biomodel of 0.14 mm, a maximum deformity of 0.75 mm, and a 1% area and a 3.6% volume reduction. Sterilization of the pieces printed using the analyzed protocol was 100% effective. CONCLUSIONS: The analyzed 3D printing protocol may be applied with any FFF-PLA 3D printer, it is safe and does not significantly alter the morphology of biomodels. These results indicate that 3D printing is associated with significant advantages for health centers as it increases their autonomy, allowing them to easily produce 3D biomodels that can be used for the treatment of fractures.

Locating the Origin of Femoral Maltorsion Using 3D Volumetric Technology-The Hockey Stick Theory.

BACKGROUND: The origin of femoral maltorsion is often unknown. However, defining the origin of the rotation of the femoral maltorsion can be useful for establishing the most suitable point to do an external derotational osteotomy. Previous studies have not considered the femoral diaphysis in their investigations of the origin of the deformity. The study of the whole morphology of the femur with 3D volumetric tools, including the femoral diaphysis can contribute to a better understanding of the behavior of femoral maltorsion. METHODS: An atypical case of unilateral femoral anteversion was selected. Both femurs were used to obtain 3D bio-models. The mirror image of the asymptomatic side was obtained and overlapped with the symptomatic femur. The Hausdorff-Besicovitch method was used to evaluate the morphologic discrepancies (in mm) between the two femurs in three zones: (1) the femoral neck, (2) the proximal diaphysis, and (3) the distal diaphysis. The differences between the two femurs were analyzed and its correlation was statistically defined using a lineal regression model. RESULTS: The deformity in the distal diaphysis increased from the supracondylar area until the apex of the antecurvatum angle (R2 = 0.91) and then decreased until the base of the femoral neck (R2 = (-0.83)), to finally increase significantly in the femoral neck area (R2 = 0.87). All of the correlations were statistically significant (p-value ˂ 0.001). CONCLUSION: The femoral maltorsion originates in the supracondylar area and its rotational axis is the longitudinal axis of the femoral diaphysis. Even though the deformity affects the femoral diaphysis, its clinical relevance is much higher in the femoral neck since the rotational axis passes through its base. Thus, the osteotomy can be conducted along all of the femoral diaphysis as long as it is done perpendicular to it.

A 3D-CT Analysis of Femoral Symmetry-Surgical Implications.

BACKGROUND: Mirroring the image of the affected side is a widely used technique for surgical planning in orthopedic surgery, especially for fractures and custom-made prostheses. Our objective is to evaluate the three-dimensional symmetry of the femurs using finite element analysis and manual alignment. METHODS: Using the computed tomography of 15 patients without lower limb pathology, 30 3D biomodels of their femurs were obtained. The error obtained through image manipulation was calculated and broken down into a rendering error and a manual overlay error. The Hausdorff-Besicovitch method was applied to obtain the total asymmetry. The manipulation error was theb subtracted from it to obtain the intrapersonal asymmetry. RESULTS: The mean intrapersonal asymmetry was 0.93 mm. It was obtained by subtracting the error derived from rendering and alignment of 0.59 mm (SD 0.17 mm) from the overall mean error of 1.52 mm (SD 1.45). CONCLUSIONS: Intrapersonal femoral asymmetry is low enough to use the mirror image of the healthy side as a reference for three-dimensional surgical planning. This type of planning is especially useful in deformity surgery when the objective of the surgery is not to restore only one specific parameter but to obtain a general functional morphology when a healthy contralateral femur is available.