Intercalary allograft reconstruction with compressed magnetic nail yielded high union rate
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Key takeaways:
- Patients who underwent intercalary allograft reconstruction with magnetic nails in compression had a 91% union rate.
- Routine postoperative compression had a higher union rate and fewer complications.
Use of magnetic growing intramedullary nails in compression may yield a high union rate in intercalary allograft reconstruction, according to results presented at the Limb Lengthening and Reconstruction Society Annual Meeting.
“[The magnetic growing intramedullary nail] gives another option for reconstruction and it improves the results of a reconstruction option that typically has multiple complications,” Lee M. Zuckerman, MD, of the department of orthopedic surgery at Keck School of Medicine of the University of Southern California, told Healio. “Based on these results, using these nails with an intercalary allograft provides a reliable option for reconstructing large defects.”
High union rate
Zuckerman retrospectively reviewed data of 16 patients with 33 osteotomy sites on seven femurs, nine humeri and one tibia. He evaluated union rates, time to union and early and late complications among patients who received a magnetic growing intramedullary nail (Precice System, NuVasive Specialized Orthopedics) to compress an intercalary allograft. According to Zuckerman, 10 patients were compressed as much as possible in the OR without routine postoperative compression. He said eight patients, including two patients who required repeat surgery from the non-compression group, had routine postoperative compression of 0.33 mm per day performed by the patient at home.
“Overall, there was a very high rate of union with both groups,” Zuckerman said. “At final follow-up, there was a 91% union rate and 85% [healed] with one surgery regardless if postoperative compression was used.”
Complications
According to Zuckerman, when comparing union rates between the two groups, 100% of patients in the compression group healed at final follow-up vs. 76% of patients in the non-compression group. He said one patient in the compression group experienced a complication compared with six patients in the non-compression group.
“In addition to the high union rate, there were no infections, only one fracture of an allograft and only one patient that had an allograft that had to be removed and replaced,” Zuckerman said. “Both of these complications occurred in the non-compression group, which is still much lower than what is typically reported in the literature.”
According to Zuckerman, three nails in the non-compression group failed and had to be replaced vs. one nail in the compression group. He said two of the failures in the non-compression group underwent revision with routine compression and healed uneventfully.
Another option
At an average follow-up of 4 years, Zuckerman said no patients experienced late complications, such as late fracture, late infection or graft reabsorption.
“Although I am cautious about these results with the sample size, routine compression appears to improve the union rate and decrease the complications of this surgery,” Zuckerman said. “The concept of using this [nail] in compression has been applied to other aspects of orthopedics, including nonunion treatment and to perform bone transport. I hope this technique gives surgeons another option to think about that may spur other ideas for innovation and provide better outcomes for our patients.”
Perspective
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Thomas J. Scharschmidt, MD, FAOA, FACS, MBOE
The authors present a retrospective review of 16 patients who underwent intercalary long bone resections with allograft reconstructions utilizing a magnetic growing intramedullary nail to compress the allograft-host junction sites. Two different techniques were used (those who underwent routine compression postoperatively compared with those who did not), and the authors report an overall healing rate of 91% (30 of 33 junctions). This is a challenging surgery with a historic nonunion rate approaching 30% for patients treated with an intramedullary device, so technical improvements are needed for this patient population.
Overall, the midterm results of this study are encouraging, and the authors should be applauded for pushing technical advances in patients requiring intercalary long bone resections. The nonunion rate was low, there were no infections and only one reported allograft failure. This compares with an overall reported complication rate of 40% or more in similar patient cohorts. Of concern, the authors report four nail failures for a rate of 25% (four of 16 patients) and this is a small, single institution study and carries all of the bias common to this approach. Regardless, the results are promising, and this technique should continue to be evaluated on a larger scale with longer follow-up to improve patient outcomes in this challenging population.
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Zuckerman LM. Compression of intercalary allografts with magnetic lengthening nails, midterm results with a comparison of techniques. Presented at: Limb Lengthening and Reconstruction Society Annual Meeting; July 11-13, 2024; Hollywood Beach, Florida.
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