Initial Patella Vertical Fracture Displacement Is a Predictor of Nonunion and Hardware Failure

Area of Science:

• Orthopedic Surgery
• Trauma Surgery
• Biomechanical Engineering

Background:

• Patella fractures are common injuries requiring surgical intervention.
• Understanding factors influencing postoperative outcomes is crucial for patient management.
• Initial fracture displacement is a potential predictor of complications.

Purpose of the Study:

• To investigate the relationship between initial vertical fracture displacement and postoperative outcomes after operative patella fracture treatment.
• To identify displacement thresholds associated with increased complication risks.

Main Methods:

• Retrospective prognostic study including 229 adult patients with operatively treated patella fractures (AO/OTA 34A-C).
• Exclusion of vertical fractures with minimal displacement (<2mm).
• Analysis of initial vertical displacement, fixation methods, and postoperative complications (nonunion, hardware failure, infection, etc.) with a minimum 6-month follow-up.

Main Results:

• A mean displacement of 21.6 mm in patients with complications versus 14.8 mm in uncomplicated cases (p=0.018).
• Significantly higher displacement in nonunion (29.8 mm) and hardware failure (30.8 mm) groups (p<0.001).
• Initial displacement >2cm identified high-risk patients; each mm increase raised nonunion/hardware failure risk by ~15% (OR=1.1, p=0.003).

Conclusions:

• Initial vertical fracture displacement is a valuable prognostic tool for predicting nonunion and hardware failure after patella ORIF.
• Displacement exceeding 2cm indicates a high risk for these specific complications.
• Suture-only and screw-with-suture fixation methods were associated with higher nonunion rates compared to other constructs.