Prospective Evaluation of Combined Internal and External Fixation for Locked Symphysis Pubis: Clinical Outcomes and Mechanical Advantages
This prospective Level I study demonstrates that a hybrid fixation strategy combining open reduction and internal fixation with a temporary external fixator yields excellent functional outcomes and high anatomical reduction rates while effectively preventing hardware failure in patients with locked symphysis pubis.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The human pelvis is a sturdy ring of bone that supports the weight of the upper body and connects the legs to the spine. When this ring breaks, it is a serious injury, often caused by high-energy events like car crashes or falls. Most breaks in the front of the pelvis involve the two pubic bones simply pulling apart, a condition doctors can usually fix by pulling them back together and holding them with a metal plate. However, there is a rare and much more difficult variation called a "locked symphysis." In this specific injury, the force of the crash is so great that one pubic bone does not just pull away; it gets wedged behind the other, like a door jammed shut by a heavy object. This mechanical lock prevents the bones from being pulled back into place with simple traction, and the intense pressure creates a high risk of damaging nearby nerves and organs if a surgeon tries to force them apart. Because the bones are stuck in a twisted, non-anatomical position, the ligaments holding the pelvis together are often completely torn, meaning that even if a surgeon manages to unlock the bones, the area remains dangerously unstable.
A team of surgeons in Egypt set out to solve this specific problem by testing a new approach that combines two different methods of holding the bones together. They studied twelve patients who had suffered this rare locked injury between 2020 and 2025. The researchers knew that using a metal plate alone often failed in these cases because the torn ligaments could not hold the plate steady, leading to the screws loosening or the plate breaking as the patient moved. To prevent this, the team developed a "hybrid" strategy. First, they surgically unlocked the jammed bones using specialized tools to gently lever them free, then they secured the bones with a standard metal plate and screws. But instead of stopping there, they added a second layer of protection: an external frame attached to the outside of the hip with pins driven into the bone. This external frame acted as a shield, taking the stress off the internal metal plate while the body's ligaments healed and scarred over. The frame was worn for six weeks and then removed, leaving the internal plate to do the work of holding the bones in place.
The results of this study showed that the combined approach worked exceptionally well. All twelve patients had their bones successfully unlocked and repositioned. In eleven of the twelve cases, the bones were placed back in their perfect anatomical position, with a gap of less than four millimeters, which is the gold standard for healing. The one patient who did not achieve perfect alignment still had a very good result, with a six-millimeter gap. Over the course of a year, no patient experienced the metal plate breaking or the screws pulling out, a failure rate that is common when surgeons rely on the internal plate alone for this type of injury. The patients also recovered their ability to walk, sit, and stand with high levels of function. By the end of the study, the average score for their physical recovery was high, with most patients reporting excellent results. There were very few complications; one patient had a minor skin infection at the site where the external pins entered the body, which cleared up with antibiotics, and another felt a temporary tingling sensation in the thigh that went away on its own.
The study suggests that for this specific, difficult injury, relying on a single metal plate is not enough because the underlying ligaments are too damaged to provide immediate stability. By adding the external frame, the surgeons created a stable environment that allowed the internal hardware to survive the critical early weeks of healing. This method proved to be a reliable way to fix a problem that is notoriously hard to treat, offering patients a better chance at a full recovery without the need for repeat surgeries to fix broken hardware. The researchers concluded that this dual-stability technique is a safe and effective solution for a complex pelvic injury that was previously difficult to manage.
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