OBJECTIVE: To compare the biomechanical properties of personalized Y-shaped plates with horizontal plates, vertical plates, and traditional Y-shaped plates in the treatment of distal humeral intra-articular fractures through finite element analysis, and to evaluate their potential for clinical application. METHODS: The study selected a 38-year-old male volunteer and obtained a three-dimensional model of the humerus by scanning his upper limbs using a 64-slice spiral CT. Four types of fracture-internal fixation models were constructed using Mimics 19.0, Geomagic Wrap 2017, Creo 6.0, and other software: horizontal plates, vertical plates, traditional Y-shaped plate, and personalized Y-shaped plate. The models were then meshed using Hypermesh 14.0 software, and material properties and boundary conditions were defined in Abaqus 6.14 software. AnyBody 7.3 software was used to simulate elbow flexion and extension movements, calculate muscle strength, joint forces, and load torques, and compare the peak stress and maximum displacement of the four fixation methods at different motion angles (10°, 30°, 50°, 70°, 90°, 110°, 130°, 150°) during elbow flexion and extension. RESULTS: Under dynamic loading during elbow flexion and extension, the personalized Y-shaped plate exhibits significant biomechanical advantages. During elbow flexion, the peak internal fixation stress of the personalized Y-shaped plate was (28.8±0.9) MPa, which was significantly lower than that of the horizontal plates, vertical plates, and traditional Y-shaped plate ( P<0.05). During elbow extension, the peak internal fixation stress of the personalized Y-shaped plate was (18.1±1.6) MPa, which was lower than those of the other three models, with significant differences when compared with horizontal plates and vertical plates ( P<0.05). Regarding the peak humeral stress, the personalized Y-shaped plate model showed mean values of (10.9±0.8) and (13.1±1.4) MPa during elbow flexion and extension, respectively, which were significantly lower than those of the other three models ( P<0.05). Displacement analysis showed that the maximum displacement of the humerus with the personalized Y-shaped plate during elbow flexion was (2.03±0.08) mm, slightly higher than that of the horizontal plates, but significantly lower than that of the vertical plates, showing significant differences ( P<0.05). During elbow extension, the maximum displacement of the humerus with the personalized Y-shaped plate was (1.93±0.13) mm, which was lower than that of the other three models, with significant differences when compared with vertical plates and traditional Y-shaped plates ( P<0.05). Stress contour analysis showed that the stress of the personalized Y-shaped plate was primarily concentrated at the bifurcation of the Y-shaped structure. Displacement contour analysis showed that the personalized Y-shaped plate effectively controlled the displacement of the distal humerus during both flexion and extension, demonstrating excellent stability. CONCLUSION The personalized Y-shaped plate demonstrates excellent biomechanical performance in the treatment of distal humeral intra-articular fractures, with lower stress and displacement, providing more stable fixation effects.
Humans ; Male ; Adult ; Healthy Volunteers ; Finite Element Analysis ; Tomography, Spiral Computed ; Models, Anatomic ; Biomechanical Phenomena ; Humeral Fractures, Distal/surgery* ; Fracture Fixation, Internal/instrumentation* ; Bone Plates ; Computer Simulation ; Precision Medicine/methods* ; Elbow Joint/surgery* ; Elbow/surgery* ; Humerus/surgery* ; Torque ; Stress, Mechanical ; Intra-Articular Fractures/surgery* ; Prosthesis Design/methods* ; Imaging, Three-Dimensional ; Range of Motion, Articular

OBJECTIVE: To investigate the difference of effectiveness between medial-lateral approach and posteromedian approach in the release of elbow stiffness after distal humeral fracture surgery. METHODS: A retrospective analysis was conducted on the clinical data of 41 patients with elbow stiffness following medial and lateral plate fixation for distal humeral fractures, admitted between January 2021 and June 2023 and meeting selection criteria. Patients were divided into the medial-lateral approach release group (study group, 20 cases) and the posteromedian approach release group (control group, 21 cases) based on surgical approach. Baseline data including age, gender, affected side, body mass index, disease duration, and preoperative extension angle, flexion angle, range of motion, visual analogue scale (VAS) pain score, Mayo elbow performance score, ulnar nerve symptoms, and heterotopic ossification showed no significant difference between groups ( P>0.05). The operation time, intraoperative blood loss, and complication incidence were recorded and compared between groups. Clinical effectiveness was evaluated using pre- and postoperative Mayo score, VAS score, elbow extension/flexion angles, and range of motion on the affected side. Statistical analysis focused on changes in these indicators relative to preoperative values. RESULTS: There was no significant difference in operation time and intraoperative blood loss between the two groups ( P>0.05). Patients in both groups were followed up 15-36 months, with a mean of 23.8 months; there was no significant difference in the follow-up time between the two groups ( t=-1.542, P=0.131). In the control group, 1 patient had obvious subcutaneous hematoma and 5 patients had poor wound healing within 2 months after operation, all of which were cured by symptomatic treatment, while no related complications occurred in the study group, there was a significant difference in poor wound healing incidence between the two groups ( P<0.05). At last follow-up, 2 patients in the study group and 3 patients in the control group had mild symptoms of ulnar nerve numbness, and there was no significant difference in the incidence of ulnar nerve symptoms ( P>0.05). All patients had no recurrence or new onset of heterotopic ossification, no skin necrosis or reoperation due to complications. At last follow-up, elbow extension angle, flexion angle, flexion-extension range of motion, VAS score, and Mayo score significantly improved in both groups when compared with the preoperative ones ( P<0.05). There was no significant difference between the change values in elbow extension angle and VAS score between the two groups ( P>0.05); the change values in flexion angle, range of motion, and Mayo score in the study group were significantly better than those in the control group ( P<0.05). CONCLUSION The medial-lateral approach can release the elbow stiffness and concurrently remove the medial, lateral, or posterior lateral plates. The incision minimizes disruption to rehabilitation exercises and reduces complications like inadequate wound healing, ultimately leading to improved treatment outcomes.
Humans ; Humeral Fractures/surgery* ; Male ; Female ; Retrospective Studies ; Elbow Joint/physiopathology* ; Middle Aged ; Fracture Fixation, Internal/adverse effects* ; Range of Motion, Articular ; Adult ; Bone Plates ; Postoperative Complications/surgery* ; Treatment Outcome ; Aged ; Humeral Fractures, Distal