Diagnosis of A3 Pulley Injuries Using Ultrasound

Abstract

Rationale and Objectives Pulley ruptures are the most common injuries in sport climbing. Ruptures of the A2 and A4 pulleys have been studied extensively, and ultrasound has proven to be a highly sensitive and specific tool for their diagnosis. However, the correct diagnosis of A3 pulley ruptures continues to be a challenge. Therefore, we investigated a novel approach to this pathology.

Material and Methods Eighteen fingers from nine different human cadavers were examined using high-resolution, dynamic ultrasound before and after being subjected to different combinations of singular and multiple iatrogenic pulley ruptures in a standardised fashion. Special attention was paid to the behaviour of the volar plate (VP) with respect to the proximal interphalangeal joint (PIP) and the flexor tendons before and after pulley rupture.

Results Injuries to the A2 and A4 pulleys were diagnosed via ultrasound with sensitivities of 90 % and 94 % and specificities of 100 % and 97 %, respectively. A direct visualisation of the A3 pulley was achieved in 61 % of the fingers. The VP became significantly thicker and shorter during finger flexion as well as after A3 pulley rupture. The distance between tendon and VP became significantly more pronounced after A3 pulley rupture. For distances greater than 0.9 mm between VP and tendon, a sensitivity of 76 % and a specificity of 94 % were achieved for determining A3 pulley ruptures.

Conclusion The distance measurement between VP and tendon was found to be a valid indirect method for the diagnosis of A3 pulley ruptures. This approach is the first ultrasound method for accurately diagnosing A3 pulley ruptures.

Zusammenfassung

Einleitung Ringbandverletzungen sind die häufigsten Verletzungen im Sportklettern. Verletzungen des A2- und des A4-Ringbandes wurden intensiv untersucht und der Ultraschall stellt das wesentliche diagnostische Mittel dar. Nachdem allerdings die Diagnose einer A3-Ringbandruptur diagnostisch noch erhebliche Schwierigkeiten bereitet untersuchten wir neue diagnostische Kriterien.

Material und Methoden 18 Finger von 9 verschiedenen humanen Kadverspendern wurden mittels dynamischem, hochauflösendem Ultraschall vor und nach standardisierten, iatrogen zugefügten verschiedenen Kombinationen an Ringbandrupturen untersucht. Hierbei wurde vor allem das Verhalten der palmaren Platte (VP) in Relation zum proximalen Interphalangealgelenk (PIP) und den Beugesehnen vor und nach Ruptur untersucht.

Ergebnisse Verletzungen des A2- und A4-Ringbandes konnten im Ultraschall mit einer Sensitivität von 90 % und 94 % und einer Spezifität von 100 % bzw. 97 % diagnostiziert werden. Eine direkte Visualisierung des A3-Ringbandes gelang in 61 % der Finger. Die VP wurde signifikant dicker und kürzer während der Fingerflexion, auch bei einer A3-Ringbandruptur. Die Distanz zwischen Beugesehne und VP wurde bei einer A3-Ringbandruptur signifikant größer. Für einen Abstand von größer als 0,9 mm zwischen der VP und der Beugesehne ergab sich eine Sensitivität von 76 % und eine Spezifität von 94 % bezüglich der Diagnose einer A3-Ringbandruptur.

Schlussfolgerung Der Abstand zwischen der VP und der Beugesehne zeigte sich als valides diagnostisches Kriterium bezüglich einer A3-Ringbandruptur. Diese Methode repräsentiert die erste ultraschallgesteuerte Methode für die akkurate Diagnose einer A3-Ringbandruptur.

Key words

sport climbing - finger injury - volar plate - pulley

Schlüsselwörter

Sportklettern - Ringbandverletzung - Fingerverletzung - Voller-Platte

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