What is Impingement Syndrome?

The ulnar styloid process is relatively far away from the anatomical position of the triangular bone. When the trauma intensity is small, the two are less likely to collide or the impact intensity is small, causing no damage to the triangular bone or slight changes in the bone marrow, so the incidence of triangular bone is low. When the trauma intensity and wrist retraction are large (especially the positive ulna variation is greater than 2 mm), the ulnar head and ulna styloid collide with the lunar and triangular bones and form a bridged state, resulting in continuous compression, which will cause the lunar and Local necrosis of the triangular bone.

Ulna impact syndrome

The ulna impact syndrome is the collision between the ulnar head and the ulnar styloid process with the lunar bone and the triangular bone, and long-term compression causes ischemic necrosis of the ulnar side of the lunar bone. Compression can also cause ischemic necrosis of the triangular bone. Because the ulnar head is adjacent to the anatomical location of the ulna, it is prone to impact and easy to form a bridging state (the ulna head is connected to the lunar bone), which results in persistent compression. Therefore, the incidence of the lunar bone in cases with positive mutation of the ulna is significantly greater than that of the triangular bone.

Brief introduction of ulna impact syndrome

The ulnar styloid process is relatively far away from the anatomical position of the triangular bone. When the trauma intensity is small, the two are less likely to collide or the impact intensity is small, causing no damage to the triangular bone or slight changes in the bone marrow, so the incidence of triangular bone is low. When the trauma intensity and wrist retraction are large (especially the positive ulna variation is greater than 2 mm), the ulnar head and ulna styloid collide with the lunar and triangular bones and form a bridged state, resulting in continuous compression, which will cause the lunar and Local necrosis of the triangular bone.

Causes of ulna impact syndrome

The causes of ulna impact syndrome can be summarized as follows:

1.Positive signs of ulna: The relationship between the articular surface of the distal ulna and the sigmoid notch of the radius, if it exceeds the positive sign of the ulna, it is equal to a suspicious positive, shorter than negative, which is one of the most important factors in the formation of this disease.

2.The triangular fibrocartilage plate is weakly developed, and the impact of the distal ulnar bone on the moon and triangle is more direct!

3. Degeneration of the triangular cartilage plate

4. Chronic strain, long-term impact.

Pathological process of ulna impact syndrome

Due to the above factors, a series of processes such as edema, degeneration, and necrosis of the lunar and triangular bones are similar to bone ischemic necrosis, but they are more limited.

Clinical diagnostic criteria for ulna impact syndrome

(1) History of wrist trauma or special hand operation;

(2) Wrist rotation or ulnar deviation, wrist ulnar pain when subjected to stress, limited wrist movement, positive ulnar tension test;

(3) There is popping and tenderness in the distal ulnar-flexo joint area, especially the dorsal and lateral sides of the ulnar-wrist joint space;

(4) Most of the wrist X-rays show that the ulna grows more than 2mm compared to the diaphyseal bone.

(5) MRI examinations of the wrist showed that most of the signals of the lunar bone and the triangular bone changed, and some of the signals of the triangular fibrocartilage changed.