Ahmed Thabet, M.D.
The natural response of our body is to heal our broken bones. This normal response happens in the majority of cases. However, in certain patients and fractures, the normal healing process is very slow or does not happen at all. Orthopedic surgeons refer to non-healing fractures as nonunions.
Once our bones are broken, blood accumulates at the fracture site due to injury to the blood vessels surrounding the bone. The accumulated blood at fracture ends is called fracture hematoma. The fracture hematoma creates an inflammatory response that starts a cascade of events that leads to bone healing. The bone is initially connected by immature bone called callus that stabilizes the broken bone ends. This immature bone is not strong enough for our normal activities and daily living. The callus becomes stronger as the times passes and eventually becomes mature bone. The flow of the blood to broken bone ends and stabilization of the fracture (using casting, nails, plates and screws, and external fixators) are critical factors to achieve normal bone healing. Any factors that disturb this normal response can generate fracture nonunion (non-healing fracture). Inadequate fracture fixation, poor blood supply to the broken bony ends and a large gap at the fracture ends can results in nonunion. If the fracture ends did not connect together, there will be excessive movement at fracture site that act like a false joint (pseudoarthrosis). This situation may be complicated with bone loss. These are devastating injuries to patients and present difficult management choices to orthopaedic surgeons. They result from acute trauma or occur after attempted surgical treatment.
The factors that cause fracture nonunion can be divided into:
- Patient factors: Each of the following factors makes it more likely for a fracture to not heal. Although most fractures will still heal in a patient with any of these factors, sometimes the combination of the severity of the fracture with one of the below factors making healing difficult.
- Diabetes mellitus: Diabetes disrupts nutrition to the bone and makes healing more difficult. Proper control of blood sugar is critical to achieve proper healing.
- Elderly: Healing ability does decrease with age.
- Patients with cancer: Chemotherapy medications attack tumor cells, which are very active. Unfortunately, it does also weaken the ability of the body to heal, as the cells necessary for healing are also very active and affected by the medications.
- Steroid therapy: Steroids also weaken the ability of the body to heal.
II – Fracture factors:
- Open fractures: The bone has broken through the skin, resulting in contamination, increased damage to the soft tissues around the bone, and sometimes loss of bone
- Comminuted fractures: These are fractures that contain multiple broken pieces. This reflects a more serious injury to the bone
- Infection: The infection overwhelms the ability of the bone to heal
- Certain fractures associated with injury to blood supply of the broken bone: Examples include the femoral neck, scaphoid, and talar neck. In these fractures the blood supply necessary to heal the bone is damaged with the fracture making healing more difficult.
The nonunion symptoms can vary from minimal pain to severe limitation of activities of daily living (ADL).
- Doctor Examination (physical exam, imaging studies, tests)
- Abnormal movement at the fracture site acts like a false joint, oftentimes this movement is painful
- Scars of old trauma or surgery will be evaluated
- Draining wounds can be present due to infection
- X-ray: these sometimes show the fracture line with the fracture ends smaller than the rest of the bone due to poor blood flow to broken bone ends (atrophic nonunion). The bone ends may also become larger and wider than the rest of the bone when the body is creating a large amount of bone in an attempt to heal the fracture (hypertrophic nonunion). The x-ray may show broken implants due to excessive movement at broken bone ends.
- Computed topography: CT is very useful to confirm the diagnosis, as a nonunion is sometimes difficult to confirm on x-ray, and CT may be useful for planning surgery
- Other tests: blood tests are important to rule out infection.
The nonunion can be managed with nonsurgical treatment. The nonsurgical treatment includes
- Bracing or casting: Sometimes with the stability of a brace or cast the body can eventually heal the nonunion
- Low signals ultrasound: There is limited data to support this approach, although in some circumstances your surgeon may recommend trying ultrasound treatment
- Electromagnetic field: There is also limited data to support this approach, although in some circumstances your surgeon may recommend trying this treatment
- Infected nonunion: This type of nonunion can be very difficult to treat. It can be treated with one or two stages of surgery
- One stage treatment: this involves removing all the unhealthy bone, and application of circular external fixator to stabilize the nonunion. The external fixator can compress the fracture ends together. The external fixator can also replace the missing bone by cutting the healthy bone (bone osteotomy) away from the nonunion site. The healthy bone can be moved gradually to lengthen at the distant site to replace the missing bone. This process is called “bone transport’’. This method is generally successful, but does involve a long and complex treatment course. The device may stay on the patient’s leg for 6-12 months, and unplanned trips to operating room are frequent to manage complications during treatment.
- Two stage treatment: This treatment option includes treatment of the infection first then management of nonunion. Multiple irrigation and debridement surgeries with complete hardware removal are necessary to treat the infection. Soft tissue coverage with flaps, where tissue is moved from other parts of the body, may be needed as well. Six weeks or longer courses of intravenous antibiotics are necessary to eradicate infection. Bracing or temporary simple external fixators can be used to stabilize the fracture until the definitive treatment. The definitive treatment included open reduction and internal fixation with intramedullary nail or plates and screws. Bone grafting is important to enhance bone healing. Massive bone grafting is needed in cases of bone loss.
- Nonunion without infection: These fractures can be treated gradually with circular external fixators (Ilizarov frames) or all at once with a plate and screws. An rod that is placed down the center of the bone can also be used. Each treatment option has its pros and cons. Bone grafting is frequently needed to achieve bone healing.
The recovery can be long – physical therapy is often required for successful return to a pre-injury or pre-operative functional level.