The flipped third fragment in femoral shaft fractures: A reason for open reduction?

First introduced by Kuntscher in the 1940s, closed intramedullary nailing of femoral shaft fractures has become the standard of care, with reported union rates up to 99% in some series. However, fractures with large intercalary segments, which are present in 10-34% of femoral shaft fractures, present unique challenges. In particular, how to treat flipped intercalary segments has remained controversial, with some advocating open reduction of these fractures. The purpose of this study was to evaluate the union rates of femoral shaft fractures with flipped intercalary segments treated with closed reduction and intramedullary nail fixation.

A retrospective review of patients with femoral shaft fractures and flipped intercalary segments from January 2000 until January 2018 was performed at a single academic level one tertiary care referral center. All patients between the ages of 16-80 with minimum 6-month follow-up were included. Union rates were evaluated using the radiographic union score of the femur (RUSF). Patients with non-diaphyseal femur fractures, pathologic fractures, incomplete radiographic or clinical follow-up, or open reduction at the time of initial surgery were excluded.

Twenty-six patients (18 male and 8 female) with a mean age of 32 years (SD 12.8, range 19-65 years) and mean follow-up of 15.9 months (range, 6-82 months) met inclusion criteria. Seven patients had open fractures. The mean size of the flipped intercalary segments was 71.3 mm (range: 30-174 mm), with mean displacement of 6.6 mm (range: 1-37 mm). The mean radiographic union scale in femoral (RUSF) at 6 months was 9 (standard deviation: 1.35). There were two patients who went on to non-union. The overall union rate was 92% (24 patients); the non-union rate was 8% (2 patients).

Though uncommon, femoral shaft fractures with flipped intercalary segments present unique challenges to surgical treatment. While previous studies have found the presence of large intercalary segments to be associated with higher rates of non-union, the results of this study challenge prior evidence. In conclusion, the presence of flipped intercalary segments may not require different surgical management than the treatment of conventional femoral shaft fractures.

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