Hexapod Circular Frame Fixation for Tibial Non-union: A Systematic Review of Clinical and Radiological Outcomes

Area of Science:

• Orthopedic surgery
• Traumatology
• Biomedical engineering

Background:

• Tibial non-unions involve complex deformities, bone loss, and infection, significantly impacting function.
• Circular frame-based treatment, particularly the hexapod system, is increasingly utilized for these challenging cases.

Purpose of the Study:

• To systematically review the clinical and radiological outcomes of hexapod fixation for treating tibial non-unions.
• To evaluate the efficacy and complication profile of hexapod systems in managing complex tibial non-unions.

Main Methods:

• A systematic review adhering to PRISMA guidelines was conducted.
• MEDLINE and Embase databases were searched for studies reporting clinical or radiological outcomes of hexapod fixation for tibial non-unions.
• Primary outcomes included radiological union and patient-reported outcome measures (PROMs); secondary outcomes assessed leg length discrepancy (LLD), tibial alignment deformity (TAD), return to activity, and complications.

Main Results:

• Nine studies involving 283 hexapod fixations were analyzed, with infection and stiff hypertrophic non-union being the most common indications.
• The average time to union was 8.7 months, achieving an 84.8% union rate.
• Over 90% of patients achieved good bony and functional results (ASAMI criteria), with 90.3% having TAD below 5° and 90.5% with LLD ≤1.5 cm. 84% returned to pre-injury activities.

Conclusions:

• Hexapod frames demonstrate favorable functional outcomes for tibial non-unions.
• Complication rates, including pin-site infections (34%), pin breakage (9%), and ankle contractures (14%), are significant and necessitate discussion.
• Further comparative studies are needed to evaluate hexapod fixation against traditional Ilizarov frames and other surgical methods.