Researchers find non–weight-bearing immobilization as effective as surgery

Surgical treatment of tarsal navicular stress fractures (TNSF) is becoming more common, said Barry P. Boden, MD, at the 2009 annual meeting of the American Ortho-paedic Society for Sports Medicine (AOSSM). This trend is based on the unproven assumption that surgery will enable patients to return to activity sooner than conservative treatments, such as casting and immobilization. But according to Dr. Boden, orthopaedists should reconsider whether an invasive treatment strategy is really the best option for their patients.

Dr. Boden presented the results of a study by lead author Joseph S. Torg, MD, that found no difference between non–weight-bearing cast treatment and surgery for TNSF with regard to outcome or time to return to activity.

“Based on our findings, non–weight-bearing immobilization should be used in initial treatment of TNSF; if weight-bearing management of both partial and complete fractures is unsuccessful, non–weight-bearing immobilization should be tried,” he asserted.

Dr. Boden added that “with today’s improved imaging techniques, it is rare for TNSF to progress as far as nonunions or displaced fractures. Thus, surgery in the form of open reduction and internal fixation (ORIF), with or without bone grafting, is rarely, if ever, indicated.”

Reviewing the literature
Researchers conducted a systematic review of published literature on TNSF treatment modalities. The search generated 31 articles (23 case reports, 4 case series, and 7 comparative cohort studies). Ten of the studies were limited to descriptive reviews of the fracture. A total of 250 fractures were identified and included in the analysis.

The studies provided information about the type of TNSF (complete or incomplete), type of treatment, result of that treatment, and the amount of time required for return to full activity. Cases were separated and compared based on the following types of treatment:

• Conservative, weight-bearing permitted
• Conservative, non–weight-bearing for 6 weeks
• Conservative, non–weight-bearing for less than 6 weeks
• Surgical treatment (ORIF, with or without bone grafting)

According to Dr. Boden, researchers considered a successful outcome to be one in which “the patient was pain-free, able to return to previous activities, and did not have a recurrence of the fracture.”

Results
No statistically significant difference was found between non–weight-bearing conservative treatment and surgical treatment regarding outcome (Table 1). Weight-bearing as a conservative treatment was shown to be significantly less effective than either non–weight-bearing (p = 0.00) or surgical treatment (p < 0.0003).

“The success rate for non–weight-bearing cast immobilization for at least 6 weeks was 96 percent,” noted Dr. Boden. “For non–weight-bearing cast treatment lasting less than 6 weeks, the success rate was 77 percent, compared to a 45 percent success rate for weight-bearing conservative treatment, and an 82 percent success rate for surgery.

“In addition, we evaluated all the patients in whom weight-bearing treatment was unsuccessful and compared secondary modalities of non–weight-bearing cast immobilization versus surgery,” said Dr. Boden. “We found no significant difference between the treatment modalities.”

He emphasized that non–weight-bearing treatment is “an absolute must” in management of these fractures. Because there’s no difference between non–weight-bearing cast treatment and surgery for TNSF with regard to outcome or time to return to activity, non–weight-bearing immobilization is indicated in the initial treatment of these fractures. Non-weight-bearing cast treatment should also be used following unsuccessful weight-bearing management of both partial and complete stress fractures of the tarsal navicular.

“Our recent data indicates that successful outcomes may be achieved for fractures immobilized less than 6 weeks, but further study is required,” added Dr. Boden. “If non–weight-bearing is maintained, the use of commercially available immobilization devices may be used for patient comfort and for maintaining ankle motion, although this also requires further research.”

Dr. Torg was the lead author of “Management of tarsal navicular stress fractures: nonoperative versus surgical treatment—a meta-analysis.” Co-authors included John Gaughan, PhD, and James Moyer, MS. Dr. Boden made the following disclosures: Amgen Co; GE Healthcare; and Johnson & Johnson. The other authors reported no conflicts.

Jennie McKee is a staff writer for AAOS Now. She can be reached at mckee@aaos.org