Management of radiation-induced fracture requires different treatment strategies

Issue: April 2011

Because the biology of a bone changes drastically following radiotherapy in musculoskeletal oncology, it is critical that these bones be treated differently for fractures that may occur years later.

A radiation-induced fracture “has to be recognized to be treated,” said Ginger E. Holt, MD, an associate professor of orthopedic surgery at Vanderbilt Orthopaedic Institute in Nashville, Tenn. “We see it most commonly in patients who are treated for metastatic cancer in the bone and patients who are treated for soft tissue sarcomas.”

Irreversible damage

Holt noted that of the 6,000 to 7,000 cases of soft tissue sarcomas treated with radiation annually in the United States, 1% to 6% of patients will eventually incur a fracture. “The radiation destroys the blood supply to the bone and damages the osteoblasts; thus, the biggest problem is that the bone never heals,” she said. “The bone has been irreversibly damaged, so the way we would normally treat fractures is completely different.”

On average, patients develop a fracture 4 years after completion of radiotherapy. “But it has been seen anywhere from 4 months to 25 years,” Holt told Orthopedics Today. “People can go on and on and on, then all of a sudden have a fracture. So it is important that physicians take a good history of the patient as to whether there has been radiation therapy or not.”

Aggressive treatment

Fractures following radiotherapy require initially very aggressive treatment. “Where you may commonly use plates and screws to fix a fracture, we often remove the bone and immediately go to a large endoprothesis,” Holt said. Conventional therapy “does not allow the bone to heal, so we can’t hold it together with plates and screws.”

The majority of patients subjected to such aggressive treatment “end up with good to excellent results,” Holt said. “And as long as the implant does not loosen, there is excellent pain relief and patients are immediately able to weight-bear.” This is in contrast to open reduction and internal fixation (ORIF) combined with intramedullary (IM) nailing, “where the chances of the bone healing is only about 50%.”

The most common vascularized bone graft for these patients is a vascularized free fibula, in order to bypass the fracture site, typically the femur. “However, this is very difficult and technically challenging surgery,” Holt said. “The biggest reported series showed that about 16 of 19 patients went on to heal their bone and had excellent results.”

Patients who undergo radiation “have very difficult wound-healing problems,” Holt said. Not only is bone negatively impacted, but skin, fat and muscle also have irreparable damage. For patients with infection, wound healing and pain that cannot be resolved, “an amputation is usually the last line of treatment for 5% to 10% of cases,” said Holt in her presentation on complications of radiation at 2011 Musculoskeletal Tumor Society Specialty Day Meeting.

Expendable bones (clavicle, fibula, portions of the pelvis) that fracture and are painful can also be removed, Holt said.

On the other hand, nonsurgical management can be beneficial in the sacrum or pelvis. “But it may take 1 to 2 years for pain to resolve,” Holt said.

Prophylactic treatment with an IM nail in high-risk radiation patients has been proposed. In addition, preoperative radiation as opposed to postoperative radiation could reduce the incidence of fractures because “the dosage is smaller and the field size is smaller,” Holt said. – by Bob Kronemyer

Reference:

Holt GE. Complications of radiation in musculoskeletal oncology. Presented at Musculoskeletal Tumor Society Specialty Day. Feb 19. San Diego.

Ginger E. Holt, MD, can be reached at Vanderbilt Orthopaedic Institute, Medical Center East, South Tower, Suite 4200, 1215 21st Ave. South, Nashville, TN 37232; 615-936-5363; e-mail: ginger.e.holt@vanderbilt.edu.

Disclosure: Holt has no relevant financial disclosure.