Ulnar Wrist Pain

Due to the many parts in this “pinkie” side of the wrist, determining the cause of ulnar-sided wrist pain can be very difficult. Your hand doctor will examine your wrist to see where the pain is located and how the wrist moves. X-rays might be taken. Sometimes other studies such as a CT scan or MRI might be needed.

While there are many potential causes of ulnar-sided pain, the most common ones are:

Bone Injuries
Fractures of the ulnar-sided, small, round bones of the wrist will result in pain after injury. Some commonly fractured bones in this location include the distal ulna, pisiform, triquetrum, and hamate. The most common trauma injuries that can crack the bone are falling onto an outstretched hand or a forceful twisting injury to the wrist.

Diagnosis of a fracture can be made with an x-ray. An x-ray will show bone alignment and any changes. If x-rays do not show a fracture or there is a question about the size of the crack in the bone, then a CT scan or MRI may be suggested.

Simple, well-aligned fractures can be treated with immobilization with a brace or cast. Rarely surgery can be needed for fractures in these ulnar-sided small bones if the bones are cracked severely.

Cartilage Injuries
Cartilage is the smooth lining of a joint whereby bones move along each other. Cartilage can be damaged from trauma or slowly worn down chronically over time. When cartilage is damaged, it can lead to “bone on bone” contact, which is painful. With age and in the setting of certain diseases, there can be a medical or genetic reason for the loss of cartilage also known as arthritis. Cartilage injuries or arthritis can lead to joint swelling and pain.

Diagnosis can be first made with an x-ray. An x-ray may show new or old fractures and cartilage space (the cartilage itself isn’t present on x-rays but the spaces where it should be present can be visualized and measured), as well as joint alignment.

Treatment for cartilage injuries can vary from a brace or cast, anti- inflammatory medication, and steroid injections. Surgery can be an option depending on the injury severity and location.

One common condition is called ulnocarpal impaction syndrome. This is a condition that arises when the ulna is longer than the radius as a result of previous trauma. This causes the ulna to “bump into” the smaller wrist bones (Figure 2). The impaction can generate pain and weakness in some situations. Treatment options are like those described above. Ultimately, surgical options may include arthroscopic surgery to help remove any irritated tissue. In some situations, shortening the ulna bone (ulnar shortening osteotomy) can help decompress the joint.

Tendon Injuries
Tendon injuries can occur from trauma and overuse. This can lead to tendon inflammation which causes pain and limited range of motion. The main tendon at risk is a tendon that extends the wrist called the extensor carpi ulnaris (ECU). This tendon glides through a small tunnel on the edge of the ulnar bone. This tendon typically is inflamed (tendinitis).

Diagnosis is usually made during an examination, but an MRI can verify the diagnosis. This can be treated with a brace or cast, anti-inflammatory medication, and steroid injections. In some cases, the tendon can dislocate out of its groove and cause clicking. This typically requires surgery to stabilize the tendon back into its groove.

Ligament Injuries
While there many ligaments around the wrist, the most injured ligament is called the triangular fibrocartilage complex (TFCC). This is a broad structure linking the radius, ulna, and carpal bones together. It is important in maintaining alignment during forearm rotation.

This structure can be sprained, partially torn, or fully torn. Some tears cause instability of the wrist. This can cause painful clicking or clunking, weakness, and limited motion. Diagnosis is usually made during an examination, but an MRI can verify the diagnosis.

These injuries can also be treated with bracing or casting, anti-inflammatory medication, and a steroid injection. Surgery may be needed in cases where there is continued pain or instability. This involves arthroscopic surgery to remove any injured tissue. In some cases, the TFCC may need to be repaired. This can be done arthroscopically or through a small incision.

Nerve Injuries or Compression
The main nerve traveling in this area is the ulnar nerve. The ulnar nerve provides feeling to the small and ring fingers. It also provides strength to several muscles in the hand. Nerve compression (similar to carpal tunnel but on the pinkie side) can cause ulnar-sided wrist pain and specifically pinkie and ring finger pain and numbness. It can start up near the elbow at the “funny bone” and travel down the ulnar side of the wrist and hand. A nerve injury (such as a laceration) can cause similar symptoms but to a more dramatic degree. Your physician may recommend an ultrasound or a nerve conduction study to better diagnose this.

Treatment may involve bracing, anti-inflammatory medication, or a steroid injection. Surgery may be needed to take pressure off a compressed nerve (decompression) or to repair an injured nerve.

Tumors
Masses or bumps are common in the wrist. Typically, masses are benign and painless. In some situations, masses can put pressure on nerves, tendons, or soft tissues. This can lead to pain, stiffness, or numbness.

Depending on the location, x-rays are usually taken and sometimes an MRI. Treatment can include simply monitoring the mass, aspiration if there is fluid in the mass, or surgery to remove the mass.

Common masses include ganglion cysts (fluid filled) and lipomas (fat collections). Malignant or cancer masses can occur in the wrist but are very uncommon.