In Song V lateral condyle fractures, the fragment is completely displaced and rotated. The cartilaginous component of the joint surface is poorly visible on X-rays, which makes it more difficult to confidently assess the quality of the reduction.
A study published in the Journal of Pediatric Orthopaedics compared ultrasound-assisted closed reduction with open reduction in this specific group of fractures [1]. Ultrasound is proposed as an intraoperative aid, especially for evaluating the articular cartilage.
What they studied
The authors retrospectively collected data from 187 children with Song V fractures of the lateral humeral condyle, treated in multiple centers between 2019 and 2023 [1].
In 96 cases, closed reduction with percutaneous pinning assisted by ultrasound was performed. The other 91 children were treated with open reduction and pinning.
Song V fractures are completely displaced fractures with a rotated fragment. Therefore, these are not the minimally displaced forms where the discussion between casting, percutaneous pinning, and arthrography is more common. These are fractures where control of the joint surface is particularly important and where, traditionally, the threshold for proceeding with an open reduction is low.
What "ultrasound-guided reduction" means
It does not mean performing the surgery without a fluoroscope.
Fluoroscopy is still used to evaluate the bone fragment, guide the pins, and check the fixation. Ultrasound is added to observe the cartilaginous component of the condyle and to look for any steps or discontinuities in the joint surface that X-rays may not show well.
The probe is placed on the elbow in multiple planes. Operators evaluate the continuity of the cartilage in the coronal and sagittal planes, the relationship between the condyle and the diaphysis, and the presence of residual displacement. If the fragment is still rotated, reduction can be completed with external maneuvers or by using a pin as a joystick.
It is therefore a technique that adds a second method of control to fluoroscopy. It does not replace the ability to reduce the fracture and does not automatically make a reduction reliable if it isn't.
Study results
The average operating time was shorter in the ultrasound-guided closed reduction group: approximately 37 minutes versus 53 minutes in the open reduction group [1].
At 12 months, radiographic and functional results were similar. The frequency of lateral condyle overgrowth also showed no significant differences: 37 cases in the ultrasound-guided group and 40 in the group treated with open reduction [1].
The percentage of results classified as good or excellent according to Flynn was very high in both groups: 98.96% after ultrasound-guided closed reduction and 97.80% after open reduction [1].
In the centers involved, ultrasound-guided closed reduction achieved short-term results comparable to open reduction and a shorter operating time. However, the retrospective design of the study does not allow concluding that ultrasound is superior.
When open reduction remains necessary
In pediatric articular fracture surgery, open reduction is not a failure.
It may be necessary when the fragment cannot be reduced, when there are interposed tissues, when rotation cannot be controlled, or when it is not possible to demonstrate with sufficient certainty that the joint surface is congruent.
The priority remains to achieve an anatomical and stable reduction, minimising damage to the soft tissues and the fragment's blood supply.
This study proposes ultrasound as a possible additional tool to achieve that goal without opening in some cases. It does not demonstrate that opening can or should be systematically avoided.
Indeed, the risk of a minimally invasive technique is precisely that of insisting too much on maintaining a closed reduction that is not convincing. At that moment, the advantage of a small incision quickly loses importance compared to the risk of leaving an articular step or residual rotation.
A technique highly dependent on experience
This is probably the main limitation to its widespread adoption.
Ultrasound of a fractured elbow is not a simple static image. One must be familiar with pediatric cartilaginous anatomy, obtain reproducible scans during surgery, and distinguish a true incongruity from an image related to the scanning plane.
In another study of the same type, among 158 children treated with ultrasound-guided closed reduction, the procedure failed in 22 cases, or 13.9% [2]. Factors associated with failure included anterior displacement of the fragment and surgery performed within the first three months of the surgeon's experience with the technique [2].
This data shows how much the procedure depends on experience. The availability of an ultrasound machine is not enough: familiarity with pediatric cartilaginous anatomy, reproducible images, and a specific learning curve are needed.
Furthermore, the available literature primarily comes from certain groups and centers that have developed particular expertise with intraoperative ultrasound in lateral condyle fractures [2,3]. This limits the general applicability of the results.
The important limitations
The study is retrospective, and treatment was not randomly assigned.
The choice between ultrasound-guided closed reduction and open reduction may have been influenced by the center, the surgeon, the characteristics of the fracture, and the perceived probability of achieving a closed reduction. It is therefore difficult to completely rule out a selection of more favorable cases for one technique over the other.
The 12-month follow-up is also short for a fracture that can show deformities, growth disturbances, necrosis, or joint alterations over time. Early functional results are important, but they do not close the issue.
Finally, the authors conclude that the technique deserves wider dissemination. Personally, this seems like a more advanced conclusion than the available data supports.
The results justify further studies and make it sensible to learn about the method. They are not yet sufficient to consider it a standard or to argue that it should be introduced into the ordinary practice of all centers.
A possible role in practice
The priority remains to correctly evaluate the fracture, achieve a reliable articular reduction, and choose the control method most suitable for the surgeon's experience and the center's capabilities.
Depending on the case, congruence can be verified with fluoroscopy, arthrography, direct visualization, or, in centers that have developed specific expertise, also with ultrasound.
The technique used matters. But it matters even more to know when that technique is not providing sufficient control and when it is appropriate to switch to open reduction.
For parents
Intraoperative ultrasound is not currently a treatment requirement or a criterion for choosing a center. What matters is that the reduction of the joint surface is reliably controlled and that, if closed reduction is not convincing, the surgeon can switch to open reduction without hesitation.
In Song V fractures, ultrasound can therefore be a support for closed reduction in centers that have developed specific experience. To establish how generalizable it is, prospective studies, independent confirmations, and longer follow-ups are needed. If control of the joint surface remains doubtful, open reduction remains an appropriate choice.
References
[1] Liu F, Zhang Y, Zhang Z, et al. Multicenter Retrospective Study of Ultrasound-Assisted Closed Reduction and Percutaneous Pinning Versus Open Reduction for Pediatric Song Type V Lateral Condylar Humerus Fractures. Journal of Pediatric Orthopaedics. Published online May 22, 2026. doi:10.1097/BPO.0000000000003330
Link: https://doi.org/10.1097/BPO.0000000000003330
[2] Kang X, Jia G, Shen X. Risk factors for ultrasound-guided closed reduction failure of unstable humeral lateral condylar fractures in children: a retrospective study. BMC Musculoskeletal Disorders. 2026;27:280. doi:10.1186/s12891-026-09601-7
Link: https://doi.org/10.1186/s12891-026-09601-7
[3] Xu J, Liu C, Jia G, Huang X. Comparison of ultrasound-guided closed reduction and percutaneous pinning fixation for unstable humeral lateral condylar fractures. Frontiers in Surgery. 2024;11:1392910. doi:10.3389/fsurg.2024.1392910
Link: https://doi.org/10.3389/fsurg.2024.1392910
Disclaimer: Content for general informational purposes only. It does not substitute for medical evaluation.
