Cross pinning effective, but more nerve damage than lateral pins

Lateral pins had a statistically significant loss of reduction vs. cross pins, but researchers question the clinical significance.

CHICAGO — Cross pinning may provide more stable reductions compared to lateral pinning for supracondylar humerus fractures. The trade off — more ulnar nerve injuries.

In a retrospective study of 1028 fractures, researchers at the Texas Scottish Rite Hospital for Children and Children’s Medical Center, Dallas, found that more patients treated with cross pins sustained reductions compared to those with lateral pinning (P<.05). Yet, they discovered iatrogenic ulnar nerve injuries in 2.9% of cross-pinned cases, but no such complications with lateral-pinned patients. An analysis of Baumann’s angle also revealed no significant differences between the treatment groups at final follow-up.

The IRB-approved research constitutes one of the largest cohort studies conducted at a single center on this topic, said Daniel J. Sucato, MD, an orthopedist at the hospital and associate professor at the University of Texas Southwestern University Medical Center, Dallas. He presented results of the study here at the American Academy of Orthopaedic Surgeons 73rd Annual Meeting.

“The humerocapitellar angles were better in the cross group,” he said. “There was more loss of reduction in the lateral group and ulnar nerve injuries were more common in the cross group. [Displaced] supracondylar fractures can be effectively treated with either cross pins or lateral pins.”

Postop nerve injury

Sucato and colleagues reviewed the medical records and postop radiographs of children treated with either cross or lateral pinning at the center between 1998 and 2005. They examined Baumann’ s angles and humerocapitellar angles on radiographs taken at postop and final healing. They also analyzed the incidence of nerve palsies and loss of reduction. “Our definition was immediate reoperation for loss of reduction, which was relatively rare, or a significant change in the fracture reduction,” Sucato said.

The study showed most patients had Type III Gartland fractures and, overall, more cases involved lateral pinning. In particular, more children who sustained Type II fractures received lateral pinning, while investigators found more boys and more cases of Type III fractures in the cross-pinned group. Children in the cross-pinned group also tended to be significantly older, Sucato noted.

The researchers found a statistically significant greater loss of reduction in the lateral-pin group (2.5% vs. 0.4%), although the clinical relevance of the finding is uncertain, Sucato said.

However, comparing procedures performed by pediatric orthopedists, they found more cases of ulnar nerve injury in cross-pinned patients (2.9% vs. 0%). “When we looked at cross versus lateral pins for Baumann’s angle at final follow-up, they’re the same,” Sucato said. Yet, the cross pins had superior humerocapitellar angles (38° vs. 34.4°), the researchers wrote in their abstract. “In the lateral pin group, greater divergence of the pins correlated with less change in the humerocapitellar angle,” Sucato said.

While the large study underscores the benefits and disadvantages of both procedures, Sucato also noted the research has limitations. “Certainly, this is a retrospective study,” he said. “It was difficult to define loss of reduction.”

For more information:
Sucato DJ, Andrade NS, Moore W, et al. Lateral vs. cross pinning for supracondylar humerus fractures: a large single institution study. #496. Presented at the American Academy of Orthopaedic Surgeons 73rd Annual Meeting. March 22-26, 2006. Chicago.