Nonunion of the hand and wrist

A nonunion is a medical condition that occurs when a broken or fractured bone fails to heal properly. This typically happens when the gap between the two broken bone ends isn't filled with new bone, resulting in a persistent gap. This gap can cause discomfort and pain, and may also lead to instability in the surrounding area. Furthermore, it can potentially increase the risk of developing arthritis in nearby joints.

Nonunions, while relatively uncommon due to modern treatments for broken bones, can still occur even with the best treatment methods. In the hand and wrist, the scaphoid bone is particularly susceptible to nonunions due to its unique blood vessel anatomy, which increases the risk of nonunion. If a nonunion develops after a scaphoid fracture, it is typically recommended to seek treatment as an untreated scaphoid nonunion can lead to a progressive pattern of arthritis known as scaphoid nonunion advanced collapse (SNAC). If SNAC arthritis develops and is not treated early, it may not be possible to treat the nonunion, and salvage surgery may be necessary. This could involve removing some of the bones in the wrist or performing a fusion (arthrodesis) of the wrist.

Other bones in the hand and wrist can also be at risk of nonunion due to a variety of factors. These include movement around the fracture site that prevents healing, infection, poor nutrition, medical problems, smoking, and severe high-energy trauma that may decrease the blood supply to the healing bone. Understanding the causes and risks of nonunion in the hand and wrist can help in early detection and treatment.

A nonunion is often suspected if there is persistent pain at the site of a fractured bone after several months of treatment. The first step in diagnosing a nonunion is typically an X-ray, which can help evaluate the healing process of the broken bone. However, additional imaging with CT or MRI scans may be necessary to better evaluate the fracture site and to assess for a nonunion.

If there is concern for other problems contributing to the nonunion, such as infection, poor nutrition, or medical problems, additional testing may be ordered. These tests can help identify any underlying issues that may be hindering the healing process. The evaluation process is crucial in determining the best course of treatment for nonunions in the hand and wrist.

Treatment for nonunions in the hand and wrist can vary depending on the specific situation. In some cases, nonoperative treatment is possible with a bone stimulator. This external device is placed over the nonunion site daily and delivers ultrasound or electromagnetic waves to the nonunion site. Treatment can last from weeks to months, and some studies have shown that these devices can improve the healing of a nonunion in certain situations.

However, in many cases, additional surgery is needed for a nonunion. The specifics of the surgery depend on a variety of factors, including which bone is involved, the type of fracture, prior treatment received, the possibility of infection, and associated medical problems. Surgical treatment options might include:

1. Debridement and internal fixation: This involves exposing the site of the nonunion, cleaning out the scar tissue at the nonunion site, and placing rigid metal hardware with plates and screws across the nonunion site to help stabilize the bone while it heals.

2. Antibiotic-impregnated cement: If there is concern for infection, a temporary piece of removable antibiotic-impregnated cement may be placed to help eradicate the infection before proceeding with definitive treatment at a future operation.

3. Bone graft: This may be used to provide structural support to the fractured bones or to provide stem cells from the bone marrow to promote healing. Bone graft can be harvested from a variety of areas on the body including from the pelvis near the hip or from the distal radius near the wrist.

4. Vascularized bone flap: This is similar to a bone graft except the bone remains attached to a blood vessel, which helps to keep the piece of bone alive. In some situations, there are “local” bone flaps that can be harvested from near the site of the nonunion. In other situations, a “free flap” may be used, in which a piece of bone from another part of the body is dissected along with the millimeter-sized blood vessel that nourishes it. This piece of bone is then transferred using microsurgical or microvascular techniques. Commonly used free vascularized bone flaps include the fibula, medial femoral condyle (MFC) from the knee, and medial femoral trochlea (MFT) from the knee.

5. Microvascular free tissue transfer (or “free flap”) surgery: This may be necessary if the nonunion is associated with an infected chronic wound in which the overlying skin and soft tissue are unhealthy and unstable. This surgery involves the harvest of skin and/or muscle from another part of the body, which is then dissected along with the millimeter-sized blood vessel that nourishes it. This tissue is then transferred using microsurgical or microvascular techniques. Commonly used free flaps for this purpose include latissimus dorsi muscle, rectus abdominis muscle, anterolateral thigh (ALT), and gracilis muscle. More details on the different options can be found at microsurgeon.org.

Surgical treatment for a nonunion often involves a combination of these approaches. It is important to have a thorough evaluation with an experienced surgeon who is familiar with all of these techniques.

Recovery after surgery for a nonunion typically requires keeping the involved bones immobilized. This often is achieved with implanted metal hardware such as plates and screws. Immobilization with a cast or splint often is necessary as well. It may take several months before the bone is fully healed. If bone graft, a vascularized bone flap, or skin/muscle microvascular free flap is harvested, then the donor site from which these were harvested also will take some time to heal.

Be sure to see an experienced surgeon to treat this condition. Our fellowship-trained specialists at The Buncke Clinic in San Francisco treat patients with nonunions of the hand and wrist from across the Bay Area and Northern California. Contact us to schedule a consultation.

Below are links for third party resources

American Academy of Orthopaedic Surgeons