What Is a Hook of Hamate Fracture?

The hook of hamate is a small but important bone in the wrist that can sustain injury from a direct blow or simply from repeated use in a particular manner. Since this injury is difficult to diagnose, it’s helpful to understand the scope and symptoms. In this article, we’ll explain all the details of a hook of hamate fracture, as well as the diagnosis, treatment, and expected outcome.

Understanding Hook of Hamate Fractures

The hamate is a small wedge-shaped bone in the hand  just beyond the wrist. This is one of eight carpal bones that work together to form the wrist joint. The hamate bone is located along the outside of the wrist on the same side as the pinky finger. The hamate bone has a small hook-like protrusion that serves as an anchor point for tendons and muscles. The so-called hook of hamate, known formally as the hamulus, forms part of Guyon’s canal, or the ulnar canal. 

A hook of hamate fracture is a rare injury that occurs when this small part of the hook of hamate bone breaks. Hamate fractures account for just 2% to 4% of carpal fractures. Since hamate fractures are notoriously difficult to diagnose, they’re often missed by health care providers. 

Causes and Risk Factors

A hook of hamate fracture is more likely among males than females. This injury is especially common among athletes who use a firm grip playing sports such as golf, tennis, hockey, or baseball. Repeated pressure from gripping and swinging a club, bat, or racquet can cause a stress fracture of the hook of hamate. 

A direct trauma to the bone can also cause a hook of hamate fracture. Grounding a golf club or absorbing the impact of a ball on a baseball bat can create the type of blow that can fracture the hook of hamate. Falling on an outstretched hand or putting your hand out in a car accident can also cause this injury. In this instance, it’s usually the force of trauma on the muscular and ligamentous attachments that ultimately causes the hook of hamate to fracture.

Diagnosis and Symptoms

The average time from injury to diagnosis for a hook of hamate fracture is four weeks. Symptoms are often unspecific, which contributes to the difficulty of this diagnosis. Hook of hamate pain usually occurs in the wrist, particularly when flexing the pinky or ring finger. A weakened grip is common, and attempting to grip objects is often painful. Other hook of hamate fracture symptoms include tenderness and swelling. 

The hook of hamate and ulnar nerve often suffer simultaneous injury. The ulnar nerve helps you move certain fingers, part of your hand, and your forearm. It also controls sensory information to the hand. If the ulnar nerve is damaged, you may also experience numbness in your hand or fingers.

Diagnosis of a hamate injury usually begins with a physical examination. The doctor may also perform a hook of hamate fracture test called a pull test, where they flex the ring and pinky fingers to determine whether this causes pain. Further tests are often ordered to confirm the injury, such as a hook of hamate X-ray, CT scan, or MRI scan. X-rays have 10% to 40% sensitivity, depending on the view in the radiograph. CT scans are far more efficient, with 92% sensitivity, while MRI scans are the most accurate method of diagnosis, offering 100% sensitivity.

Treating a Hook of Hamate Fracture

Broken hamate bone treatment options vary depending on the nature of the injury. If the bones are still in their proper position, you may recover by immobilizing the wrist in an ulnar gutter cast. Although immobilization is an appropriate strategy, as many as 50% of patients experience non-union with this approach. Despite the non-union, most patients are pain-free and enjoy a full range of motion.

If the fracture is displaced, meaning the bones have shifted out of position, surgery is the best hook of hamate fracture treatment. Surgery is also recommended for high-level athletes.  During the surgery, the bones are secured in place with wires and screws. Pins and bone grafts may also be incorporated into the surgical procedure. 

Recovery and Complications

Broken hamate bone recovery for a non-displaced fracture can take as little as six to eight weeks. If you opt for surgical treatment, you can sometimes return to full activity within six weeks. Depending on the nature of the injury and the type of surgery, you may take three to six months to make a full recovery. It’s important that you fully participate in any prescribed physical therapy during this time. Engaging in the appropriate stretching and strengthening exercises will help maintain range of motion, improve mobility, and enhance strength.

When To Consult a Health Care Professional

It’s important to consult a health care professional for hamate fracture management as soon as possible. The sooner this injury is addressed, the better the outcome and the shorter the hamate bone fracture recovery time. If you experience unexplained pain, numbness, or swelling in your hand or wrist, you should speak with a health care professional. You should also consult a health care professional if you’ve had a diagnosed hook of hamate fracture and you’re not experiencing a satisfactory hamate fracture recovery. It’s not uncommon to have difficulty with fusion with this bone.

Contact The Hand and Wrist Institute for a Skilled Diagnosis

If you’re suffering from wrist pain, we can help you identify the cause and determine the best treatment plan, regardless of what type of condition you face. At the Hand and Wrist Institute, we have more than 25 years of experience specializing in hand and wrist conditions. Our team effectively addresses sports injuries, animal bites, burn scarring, and more throughout the Dallas and Fort Worth area. Contact us today for a consultation.

man playing golf during daytime by Courtney Cook is licensed with Unsplash License 

Dr. John Knight

Dr. Knight is a renowned hand, wrist and upper extremity surgeon with over 25 years of experience. Dr. Knight is a Board Certified Orthopedic Surgeon and Fellowship trained. Dr Knight has appeared on CNN, The Doctors TV, Good Morning America, The Wall Street Journal, The Washington Post, Forbes, The Huffington Post, Entrepreneur, Oxygen network and more.