Bisphosphonate rescue in distraction osteogenesis: a case series.

Area of Science:

• Orthopedics
• Regenerative Medicine
• Pharmacology

Background:

• Distraction osteogenesis stimulates bone and tissue generation but can be complicated by bone resorption (catabolism), leading to regenerate insufficiency.
• This insufficiency may result in regenerate bending or fracture, particularly in stress-shielded environments like external fixators.

Observation:

• Seven patients with regenerate insufficiency after limb lengthening using Ilizarov devices received intravenous bisphosphonates (pamidronate or zoledronic acid).
• Pre-treatment dual-energy x-ray absorptiometry showed reduced bone mineral density (BMD) in the lengthening sites.
• Patients had a mean age of 13.8 years, with lengthening sites in the proximal tibia or distal femur.

Findings:

• Six out of seven patients showed rapid and sustained improvement in local BMD after bisphosphonate treatment, allowing fixator removal without further intervention.
• BMD increased to a mean of 85.6% of the healthy side in responding patients.
• One patient did not respond to bisphosphonates and subsequently healed with bone morphogenetic protein 7 and bone marrow injection.

Implications:

• Bisphosphonate therapy is a promising, minimally invasive treatment for limb bone regenerate insufficiency by reducing catabolism.
• This approach may decrease the need for extensive surgical reintervention in cases of failed regenerate.
• Further research into bisphosphonates' role in distraction osteogenesis complications is warranted.