Comparative study between fixed-angle and polyaxial screws in distal radius fixation with two volar locking plates

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Radiology

Background:

• Distal radius fractures are common, often treated with volar locking plates (VLPs).
• Numerous plate-screw designs exist, but no single system demonstrates clear superiority.
• Understanding screw behavior is crucial for optimal fracture fixation and patient outcomes.

Purpose of the Study:

• To compare the efficacy of fixed-angle (FA) versus polyaxial (PA) screws in distal radius VLP fixation.
• To evaluate screw protrusion, reduction preservation, and intra-articular penetration between the two screw types.

Main Methods:

• Prospective cohort study of 80 patients with distal radius fractures treated with VLPs.
• 40 patients received PA VLPs, and 40 received FA VLPs via the flexor carpi radialis approach.
• Postoperative CT scans assessed screw protrusion; loss of reduction was measured over 12 months.

Main Results:

• No significant difference in the rate of dorsal screw protrusion between PA and FA groups.
• Fixed-angle screws resulted in shorter protruding screws compared to polyaxial screws (p<0.05).
• Polyaxial screws demonstrated better preservation of radial height (p<0.05), while loss of reduction was similar between groups.

Conclusions:

• Both FA and PA screw systems exhibit comparable screw protrusion rates in distal radius VLP fixation.
• Polyaxial screws offer an advantage in maintaining radial height, whereas fixed-angle screws may be associated with shorter dorsal screw penetration.
• Dorsal and intra-articular screw protrusion are more frequent than anticipated, regardless of screw type.