Elizabeth Hofheinz, M.P.H., M.Ed.
Wondering about the best way to handle flipped intercalary segments in femoral shaft fractures?
Read on… 
Researchers from Virginia Commonwealth University and the University of California Los Angeles have assessed the union rates of femoral shaft fractures with flipped intercalary segments treated with closed reduction and intramedullary nail fixation.
Their work, “The flipped third fragment in femoral shaft fractures: A reason for open reduction?” appears in the March 1, 2021 edition of Injury.
Asked why this issue hasn’t been addressed much in the literature, co-author Christopher Lee, M.D., an Assistant Professor of Orthopaedic Trauma at the David Geffen School of Medicine at UCLA, told OSN: “I think the reason for this is in large part due to its relatively rare occurrence in most femoral shaft fractures treated. With intercalary fragments, they are often partially reduced or maintain some of their soft tissue attachments and remain relatively well approximated following shaft fixation.”
“In rare circumstances, that intercalary fragment becomes flipped inside out. In some of the conversations that I’ve had with orthopaedic traumatologists throughout the country, when this unusual circumstance occurs, there are a wide range of ideas that people have in terms of what should be done. This can range from percutaneous methods to try and re-flip the fragment, to as aggressive as larger open approaches to reduce the fragment. Still, there are people who believe these fragments will integrate well without intervention.”
“While some work has been done previously on large intercalary shaft fragments, fragments with reversed morphology were only discussed in subset analyses. As intramedullary fixation has become the mainstay of treatment, and as our indications for use of intramedullary fixation have expanded, it becomes imperative that we analyze the various circumstances that can arise, regardless of rarity, that can contribute to worse clinical outcomes.”
A total of 26 patients (18 male, 8 female) with a mean age of 32 years and mean follow-up of 15.9 months met the 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),” wrote the authors.
Dr. Lee told OSN: “Some of the most surprising findings were that contrary to previous reports, these large intercalary fragments with reversed morphology went on to heal at a rate of 92% without any additional intervention. In a sense, the idea of ‘less is more’ is quite appropriate for fractures with these characteristic intercalary fragments. I think it also reaffirms the long-held principle in treating femoral shaft fractures of maintaining length, alignment, and rotation over an anatomic alignment, and to respect the biology of the fracture.”
“As a retrospective study, there are obvious limitations, as causality cannot be inferred. I think what this study has showed us is that these relatively rare fracture patterns need to be further explored. To start, a multicenter prospective study would be ideal. We need larger numbers, and as these occur at such a relatively rare event rate, the inclusion of multiple academic centers would be useful. If prior research has taught us anything, it’s that examining small numbers that are easily influenced by a few cases can be deceiving and may deliver the wrong message. The power, so to speak, is in the numbers, and it is something we will need more of in future studies.”
