Information About the Field of Scaphoid pseudarthrosis
What exactly is a scaphoid pseudarthrosis?
A pseudarthrosis is the medical term for describing a nonunion of bone fragments, when a fracture fails to heal properly.
The scaphoid, one of the carpal bones involved in forming the wrist joint, is particularly prone to pseudarthrosis development. In up to 10% of scaphoid fractures, a nonunion may occur.
As a long-term complication, this can lead to a collapse of the carpal bones, a condition known as SNAC wrist (Scaphoid Nonunion Advanced Collapse). This condition results in progressive wrist osteoarthritis which is accompanied by intense wrist pain, reduced grip strength, and restricted range of motion.
Causes: How does a scaphoid pseudarthrosis develop?
The most common cause of a pseudarthrosis in the scaphoid is impaired blood flow. The scaphoid, particularly its proximal part (closer to the wrist), has a relatively poor blood supply. As a result, fractures in this are associated with an increased risk of developing pseudarthrosis.
Other causes or risk factors for nonunion following a bone fracture:
- Premature or excessive loading
- Infections
- Soft tissue (e.g. torn ligaments) within the fracture gap
- Diabetes mellitus
- Peripheral arterial disease (PAD)
Symptoms: How does a scaphoid pseudarthrosis manifest?
The scaphoid fracture or the development of a pseudarthrosis itself, does not cause symptoms initially. Furthermore, even when medical evaluation is sought, this type of fracture is very difficult to detect on a standard X-ray. For this reason, scaphoid fractures are the most frequently overlooked bone fractures.
In advanced stages of scaphoid pseudarthrosis, patients may experience pain on the thumb side of the wrist, especially during activities such as lifting objects, wrist extension, and later even at rest.
Treatment: How is a scaphoid pseudarthrosis treated?
Treatment of a scaphoid pseudarthrosis usually requires a surgical intervention. In certain cases, for instance when there is only a delayed bone healing with a narrow fracture gap, conservative treatment can be successful. Examples for such treatments involve immobilization of the wrist in combination with ultrasound or shockwave therapy. However, long-standing pseudarthrosis should generally be treated surgically.
Surgery: What is the procedure for scaphoid pseudarthrosis surgery?
The surgical technique used primarily depends on an intact blood supply to both fragments of the scaphoid.
If vascular blood supply is preserved, a bone graft may be harvested from the iliac crest or the radius and inserted into the pseudarthrosis gap. Harvesting from the iliac crest requires general anesthesia, whereas grafts taken from the radius allow for the use of a safer regional anesthetic of the affected arm as an alternative to general anesthesia. After the harvesting the bone graft, an incision is made either on the palm or the back of the hand, depending on the location of the pseudarthrosis, exposing the scaphoid. The nonunion site is excised and filled with bone graft. The bone fragment may be stabilized with wires, screws, or a small metal plate if necessary.
If the proximal fracture fragment is no longer adequately perfused with blood, or if the above-described surgical technique has failed, a vascularized bone graft must be transplanted. In most cases, a bone segment with its associated blood vessel is harvested from the radius. The advantage of this methods is that the vessel does not need to be detached from its origin, due to the anatomical proximity between the radius and the scaphoid. Alternatively, a vascularized bone graft can also be harvested from other distant bones, such as the femur. In this case, the accompanying blood vessel must be connected to the local blood vessels in the wrist.
In cases of advanced and long-standing pseudarthrosis, that already have caused carpal collapse and sever osteoarthritis, symptomatic treatment such as surgical denervation may be considered. This involves severing the pain conducting nerve fibers of the nerve that supplies the carpal region, to alleviate the severe pain associated with the osteoarthritis.
Aftercare: What should be considered following treatment?
Surgical treatment of a scaphoid pseudarthrosis generally requires inpatient hospitalization.
Depending on the surgical technique, the wrist must be immobilized in a cast or splint for several weeks to months. It is important to note that smoking can negatively impact wound healing. Moreover, a follow-up X-ray is performed a few weeks after the surgery to assess bone healing. Following the immobilization, gradual load-bearing and functional recovery are supported through regular physiotherapy and occupational therapy.
Who covers the costs of treatment for scaphoid pseudarthrosis?
The costs for surgical treatment for scaphoid pseudarthrosis are generally covered by both, public and private health insurance. However, conservative therapies such as shock wave or ultrasound therapies are usually not reimbursed by statutory health insurance. These treatments are mainly covered by private health insurances or employers’ liability insurance associations (in German: Berufsgenossenschaften) if the pseudarthrosis results from a workplace accident.
What physicians and clinics specialize in treating scaphoid pseudarthrosis?
Hand surgeons are the specialists in both, diagnosing and treating conditions such as scaphoid pseudarthrosis. The subspecialty in hand surgery is awarded to physicians, in addition to their board certification in either surgery or orthopedics, who have subsequently undergone specialized training in hand surgery.
If surgical treatment is necessary, it should not be performed as an outpatient procedure, but rather through the hand surgery department of a hospital or alternatively, through a specialized hand surgery practice that has admitting privileges at a hospital.
Patients seeking medical attention naturally want the best possible medical care. This raises the question: Where can I find the best clinic for my needs? Since this question cannot be answered objectively and no reputable physician would claim to be “the best”, one must rather rely on a physician’s experience and specialization.
We are here to help you find an expert for your condition. All listed physicians and clinics have been carefully reviewed and selected based on their outstanding expertise in the treatment of scaphoid pseudarthrosis, and they look forward to hearing from you.