CORR Insights(®): What Injury Mechanism and Patterns of Ligament Status Are Associated With Isolated Coronoid, Isolated Radial Head, and Combined Fractures?

Reliability of dynamic fluoroscopy for medial elbow stability in the presence of radial head resection

Background

The aim of this study was to examine whether dynamic fluoroscopy is reliable for assessment of medial elbow stability in the presence of radial head resection and different stages of medial collateral ligament (MCL) dissection in a cadaveric elbow model.

Materials and methods

Six intact elbow specimens were measured for joint angulation while applying valgus stress in four examination conditions (Examiner 1, Examiner 2, 1 Nm, 2 Nm) in four different elbow positions (fully pronated or supinated at 0° of elbow extension and 30° of elbow flexion). The elbow specimens were examined for valgus stress in three stages: (1) intact, (2) after radial head resection, and (3) after subsequent dissection of the complete MCL. Anteroposterior radiographs of the elbow were made at each stage to determine joint angulation. Intraclass correlation coefficients (ICCs) were calculated.

Results

In intact elbows, mean joint angulation ranged from 2.2° ± 2.0 (1 Nm) to 5.2° ± 2.3 (Examiner 1). Radial head resection did not increase joint angulation during valgus stress, regardless of joint position and examination condition (Examiner 1: 5.5°; Examiner 2: 5.0°; 1 Nm: 2.6°, 2 Nm: 3.9°). Additional dissection of the MCL led to significantly higher joint angulation during measurements with the standardized torques (1 Nm: 12.4°; 2 Nm: 23.3°). Very good to excellent ICCs for joint angulation between Examiner 1 and Examiner 2 (0.861 to 0.959) were found.

Conclusion

Dynamic fluoroscopy is a reliable diagnostic tool for determining medial elbow stability in the presence of radial head resection and different stages of MCL dissection.