Session I - Polytrauma / Pelvis / Post-Traumatic Reconstruction

Thurs., 10/10/13 Polytrauma/Pelvis/Post-Trauma, PAPER #38, 4:35 pm OTA 2013

Dynamizations and Exchange Nailing: Success Rates and Indications

Jody Litrenta, MD1; Paul Tornetta, III, MD1; Cory A. Collinge, MD2; Heather A. Vallier, MD3; Clifford B. Jones, MD4; Christiane G. Kruppa, MD4; Reza Firoozabadi, MD5;
Kenneth A. Egol, MD6; Ross K. Leighton, MD7; Mohit Bhandari, MD8;
Emil H. Schemitsch, MD9; David W. Sanders, MD10;
1Boston University Medical Center, Boston, Massachusetts, USA;
2Texas Health, Fort Worth, Texas, USA;
3MetroHealth Medical Center, Cleveland, Ohio, USA;
4Orthopaedic Associates of Michigan, Grand Rapids, Michigan, USA;
5University of Washington, Seattle, Washington, USA;
6NYU – Hospital for Joint Diseases, New York, New York, USA;
7Dalhousie University, Halifax, Nova Scotia, Canada;
8McMaster University, Hamilton, Ontario, Canada;
9St. Michael’s Hospital, Toronto, Ontario, Canada;
10London Health Science Centre, London, Ontario, Canada

Background/Purpose: Tibial nailing is an accepted and successful treatment for tibia fractures; however, the secondary intervention rate for tibia fractures in large trials has been reported to be >15%. When nailed fractures go on to delayed or nonunion, exchange nailing and dynamization are two common secondary interventions. There are no data comparing union rates in like patients and little data available at all regarding dynamization. The purpose of this study is to report on the timing, indications, and success rates of dynamization and exchange nailing in a multicenter study and to compare these two techniques where appropriate.

Methods: The records and radiographs of 183 tibia fractures in multiple centers that had dynamization or exchange nailing for delayed/nonunion were reviewed. Delayed/nonunion was defined as at least 3 months postsurgery with no progression. Demographic data, fracture type, cortical contact/gap, timing of and success rates of the secondary intervention, and RUST (Radiographic Union Score for Tibial fractures) scores at intervention and follow-up were recorded. Success was defined as obtaining union while nonunion or additional intervention defined failure. Two-tailed t tests and Fisher exact or χ2 with P set at <0.05 for significance were used as indicated.

Results: A total of 183 tibia fractures underwent dynamization (92) or exchange nailing (91). The average age was 39 years (range, 16-81). There were 141 men and 42 women. Mechanisms of injury were motor vehicle accident (MVA) (53), motorcycle accident (MCA) (47), pedestrian struck (26), falls (28), direct blow (16), and other (13). There were 112 open (50% grade III) and 71 closed fractures in the proximal (21%), midshaft (30%), or distal (49%) tibia. No statistical differences were found between the dynamization and exchange nailing groups with respect to demographics or fracture characteristics, although a gap or bone defect was more common in the exchange group (20% vs 34%, P = 0.06). The success rates of the interventions were not different for exchange nails (P = 0.3) or dynamizations (P = 0.75) performed early versus after 6 months nor were the RUST scores for successful versus failed procedures (P = 0.96 and 0.43) allowing for pooling of the data. 14 patients were lost or are currently in follow-up, leaving 169 fractures followed to union or failure.

Table 1 details the primary results:

The RUST scores at the time of intervention were not different for successful or failed dynamizations (7.02 vs 7.0, P = 0.96) or exchanges (6.5 vs 7.2, P = 0.43). Likewise, the time to successful versus failed dynamization (170 vs 169 days, P = 0.97) or exchange nailing (231 vs 191 days, P = 0.33) was not different. However, no cortical contact or a gap was a statistically negative factor for both exchange nails (P = 0.09) and dynamizations (P = 0.06). When combined, the success in the face of a gap was 78% versus 92% when no gap was present (P = 0.03).

Conclusion: Prior literature has few reports of the success rates of distant site interventions for tibial nonunions. The indications for dynamization and exchange were similar with RUST scores of 6.7 versus 7.1 and the median time to intervention close to 6 months in both groups. Having no cortical contact or gap favored having an exchange nail performed, and was a negative prognostic factor for both procedures. The current study demonstrates high rates of union for both dynamization and exchange nailing making both viable options.

Alphabetical Disclosure Listing

• The FDA has not cleared this drug and/or medical device for the use described in this presentation   (i.e., the drug or medical device is being discussed for an “off label” use).  ◆FDA information not available at time of printing. Δ OTA Grant.