Scaphoid fractures are relatively common and non-union will occur in up to 15-25% of patients despite treatment such as cast immobilisation or surgical fixation. Scaphoid fractures that do not heal within a few months of injury are termed scaphoid delayed union. Although there is no consensus on the exact timescale for classifying a scaphoid fracture as a non-union, the absence of bone union at more than 6 months following injury is commonly accepted. Occasionally, the scaphoid fracture fragments will stabilise due to a ‘fibrous’ union with scar tissue, which generally provides milder symptoms when compared to mobile non-unions.

The scaphoid is more susceptible than most other bones to non-union following fracture (break) due to its mobility and fragile blood supply. The risk of scaphoid non-union is greatly increased if the fracture is not treated appropriately in the few weeks following injury. The risk is also increased when fracture fragments are poorly aligned and for fractures positioned closer to the forearm (termed proximal pole fractures). The likelihood of non-union is also increased in smokers, older adults and those with certain medical conditions.

Sometimes scaphoid fractures fail to heal despite appropriate treatment and no risk factors.

Some of the potential symptoms of scaphoid fracture non-union are listed below.

Typically present:

• Pain on the thumb side of your wrist that is worse with activity or gripping.

• Reduced grip strength (weakness)

Sometimes present:

• Wrist swelling at the site of your pain.

• Clicking or clunking with wrist movements.

• Wrist stiffness (reduced range of movement).

It is important to correctly diagnose scaphoid fracture non-union and exclude other causes of wrist pain, such as scapholunate ligament injury or De Quervain’s tenosynovitis. The diagnosis is usually made on the history (your symptoms) and clinical examination. Plain radiographs (X-rays) are essential to confirm the diagnosis. A CT scan is used to assess the fracture and assess for any local wrist arthritis.

Scaphoid fractures that have not healed (scaphoid non-union) may be treated with surgery unless there is associated arthritis or factors that make successful bone union unlikely. When scaphoid fracture non-union is associated with local arthritis, treatments will usually focus instead on symptom control, such as pain relief. The treatment options for scaphoid non-union arthritis (also termed SNAC arthritis) are not detailed here.

• Non-surgical treatment options include painkillers, avoidance of painful activities, wrist splintage and physiotherapy (including functional advice). With established non-union, the scaphoid will not heal with non-surgical treatment. If wrist symptoms are mild or absent, the option to live with the non-union is sometimes the best option to avoid the risks of surgery.

• Surgical treatment options aim to stabilise the scaphoid fracture fragments to achieve bone union. Stabilisation can be achieved with screw fixation and/or wires. Fixation will usually be accompanied by bone graft to fill the fracture gap, which can be taken from the wrist (radius bone) or pelvis (iliac crest) depending on the type and amount of bone required. Fractures near the middle of the scaphoid (termed waist fractures) are often approached from the palm side of the wrist. Fractures closer to the forearm arm (termed proximal pole fractures) are often approached from the dorsum (back) of the wrist. Following fixation and grafting, the wrist will be kept immobilised in a cast for up to 3 months. A second operation to remove temporary wrist wires at around 8 weeks is sometimes required (under local anaesthesia). A CT scan may be completed to confirm if bone union has been achieved.

Surgery for scaphoid fracture non-union is usually performed under general anaesthesia. Click here for an overview of the different types of anaesthesia and the general risks of hand surgery. The additional and specific risks associated with surgery for scaphoid fracture non-union will be discussed if surgery is an option, but includes wrist stiffness and approximately 20% risk of continuing non-union. The likelihood of union reduces with a treatment delay of more than one year following injury.

You can read more detailed information regarding scaphoid fracture non-union on the Lothian Hand Unit website.