The medial deviation of the ulnar axis due to congenital or acquired factors, with a carry angle <0° is called elbow entropion. 1.Elbow deformity
That is, after the elbow joint injury is treated (or untreated), there is a significant increase in the inversion angle of the elbow joint in the straight position, which can reach 15° to 35° in severe cases, at which time the posterior triangle of the elbow changes and the distance between the epicondyle and the hawk is widened. 2. Dysfunction The general activities of the elbow joint can be basically normal, but all have different degrees of muscle strength reduction. 3.Measurable on radiographs
The angle of elbow inversion can be shown from the measurement, i.e. the angle between the two lines of the longitudinal axis of the humerus and the longitudinal axis of the ulna, which is 10° to 15° of the carry angle of the elbow joint (i.e., in an outward turning shape); the angle becomes inward turning when the elbow is inward turning. Treatment Elimination of pain, improvement of function and correction of deformity are the three goals of elbow inversion treatment, the first two of which are the main ones. The first two are the main goals, but those with mild clinical symptoms due to occupational requirements or a strong desire for orthopedic treatment are treated differently. It is generally accepted that only work and life guidance should be given to patients with a small inversion angle, mild elbow pain, and good elbow function. If the deformity is severe, the inversion angle is about 30°, the pain is severe, and the dysfunction of the elbow joint affects daily work and life, surgery should be considered. Supracondylar osteotomy of the humerus is used to correct the valgus deformity and restore the valgus angle, which can eliminate pain and improve function. Wedge osteotomy is the commonly used method, while triangular flap osteotomy and “V” shaped osteotomy are more complex and require accurate design and careful operation. Regardless of the type of osteotomy, the osteotomy site needs to be fixed, and the fixation method can be external or internal fixation. For patients with elbow entropion secondary to elbow osteoarthritis or ulnar neuritis, in addition to osteotomy to correct the deformity, the secondary lesions should be treated accordingly. X-ray examination can confirm the diagnosis of elbow entropion and measure the angle. Pathogenesis 1. Supracondylar fracture of the humerus
It is the most common cause, accounting for about 80% of all elbow inversions. The incidence of supracondylar humerus fractures with elbow entropion has been reported to be 30% to 57%. Most scholars believe that the cause is due to the medial tilt of the distal end of the fracture. Studies have shown that poor post-fracture repositioning, medial bone compression insertion, separation of the lateral end of the fracture and distal internal rotation and torsion of the distal end of the fracture are the main causes of medial tilt of the distal end of the fracture. 2. Total distal humeral epiphyseal separation and medial condyle epiphyseal injury
The injury is likely to produce early epiphyseal closure and cause elbow deformity, and may also cause ischemic necrosis of the medial humeral condyle, slowing or stopping the growth of the medial humeral condyle, and eventually leading to elbow inversion. 3. Poorly repositioned medial humeral condyle fractures are also common, especially when swelling is evident, which may cause reset failure or failure to replace the cast in time after repositioning. 4.Old elbow dislocation is less common and mostly occurs in complicated cases.