Bioabsorbable vs. titanium screws for first tarsometatarsal joint arthrodesis: An in-vitro study

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Biomechanics

Background:

• First TMT-1 joint arthrodesis is a common procedure for severe hallux valgus.
• Current fixation methods often involve titanium or steel screws and plates.
• Ideal fixation materials require strength, rigidity, biocompatibility, and minimal interference with healing.

Purpose of the Study:

• To compare the biomechanical performance of bioabsorbable cannulated screws against titanium screws in TMT-1 arthrodesis models.
• To evaluate the suitability of bioabsorbable screws as an alternative fixation in orthopedic procedures.

Main Methods:

• Thirty anatomical TMT-1 arthrodesis models were created using a saw.
• Bioabsorbable and titanium screws were inserted identically into each model.
• Models were subjected to load-to-failure testing using a material testing machine at a 15° angle.

Main Results:

• Titanium screws exhibited significantly higher mean yield load (81.2 N vs. 61.4 N) and maximum failure load (120.6 N vs. 85.1 N) compared to bioabsorbable screws.
• Fixation stiffness was also greater with titanium screws (9.7 N/mm vs. 8.1 N/mm).
• Bioabsorbable screws showed a higher incidence of bending-induced failures.

Conclusions:

• Titanium screws provide superior biomechanical strength and stiffness in TMT-1 arthrodesis models.
• Bioabsorbable cannulated screws may be a potential alternative for fixation in the Lapidus procedure, despite lower performance in this specific model.
• Further clinical evaluation may be warranted for bioabsorbable screw applications.