Decreased femoral fracture load after cephalomedullary nail removal

Listen to Brian and Lisa discuss the paper 'Decreased femoral fracture load after cephalomedullary nail removal' published in the May 2025 issue of Bone & Joint Research.

Click here to read the paper.

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Transcript

[00:00:00] Welcome back to another episode of AI Talks with Bone & Joint, brought to you by the publishers of Bone & Joint Research. Today we're delving into the paper 'Decreased femoral fracture load after cephalomedullary nail removal', published in May 2025 by GM Schwarz and colleagues. I am Brian, and with me is my co-host Lisa.

Hello, Brian. Today's topic is quite fascinating. This study explores the biomechanical effects of removing cephalomedullary nails, which are often used for internal fixation of femoral fractures. Even after these fractures have healed, removing the nails can lead to complications.

The study aimed to assess the initial postoperative failure load following hardware removal and specimens with a history of cephalomedullary nails. To do this, the researchers examined 20 specimens from body donors. 10 had cephalomedullary nails, due to  pertrochanteric or subtrochanteric fractures, while the other 10 served as a control [00:01:00] group.

Their findings were quite revealing. The femora from the group that had nails removed showed significantly lower failure loads compared to the control group. Specifically, the failure load was 1,835 newtons versus 4,523 newtons in the control group. Quite a marked difference.

Indeed, they also observed differences in the types of fractures. Post removal, most fractures were subcapital buckle-type, as opposed to the transcervical fractures seen in the control group. These changes likely stem from alterations in the biomechanical properties of the femur, due to the presence of femoral neck screws.

The study included detailed biomechanical testing with femur set in a single-leg stance, a critical position as spontaneous fractures are often reported in such stances rather than during falls. They also measured volumetric bone mineral density, BMD, at the proximal femoral neck [00:02:00] and distal epicondyles.

Interestingly, the study found that femora with the nail removed had a lower ratio of proximal to distal volumetric BMD indicating altered stress distribution. Specifically, the volumetric BMD was 97.82 milligrams per cubic centimeter, approximately in 129.37 milligrams per cubic centimeter distally for the nail removal group compared to 199.41 milligrams per cubic centimeter and 178.58 milligrams per cubic centimeter in the control group.

This lower volumetric BMD in the femoral neck region suggests weaker bone where strength is crucial, likely the reason for these types of fractures. Additionally, the altered force transmission due to femoral neck screws probably leads to these biomechanical changes over time.

A key point the researchers highlight is the clinical impact. [00:03:00] They advise caution with elective removal of cephalomedullary nails due to the increased risk of subcapital neck fractures, which might necessitate more severe surgeries like hip arthroplasty.

Absolutely. They even recommend a strict postoperative partial weightbearing regimen for an extended period if nail removal is unavoidable. This underscores the study's broader implication that managing patients' post-removal requires meticulous planning to prevent complications.

In conclusion, the study underscores that removing cephalomedullary nails poses significant risks due to altered bone density and stress distributions. Such findings can aid clinicians in managing the postoperative period better and possibly in reconsidering elective removal in elderly patients.

The insights from this study not only enhance our understanding of femoral biomechanics, post nail removal, but also influence clinical decision-making to improve patient outcomes.[00:04:00] 

Thank you, Lisa and thanks to our listeners for tuning into AI talks with Bone & Joint. Be sure to read the full study in the May issue of Bone & Joint Research.

Until next time.