Underestimation of alleged Rockwood II injuries-Don’t miss horizontal instability

Abstract

Background

There is broad consensus that Rockwood type II injuries are treated conservatively. However, several studies have shown that some of these patients have persistent mid- to long-term symptoms, partly due to horizontal instability.

Patients and methods

Patients with a side-to-side difference of up to 25% in the coracoclavicular distance on bilateral stress radiographs were included in this case series if they had either a posterior subluxation of the distal clavicle on axial radiographs and/or on MRI (in 8 patients), or if they showed dynamic posterior instability both clinically and radiologically. Injuries other than Rockwood type II or Rockwood type II injuries without horizontal instability were excluded.

Results

During the period from 2015 to 2022, 13 patients with an average age of 30.7 years (range 21–48 years) fulfilled the inclusion criteria. The mean time from trauma to final diagnosis was 32.4 days (range 7–67 days). Eight patients had an additional static posterior dislocation of the distal clavicle consistent with a Rockwood type IV injury. Five patients had dynamic posterior instability. All patients had initially been classified as having Rockwood type II injuries based on the findings of bilateral stress radiographs at the referring institution.

Conclusion

The diagnosis of a Rockwood type II injury should not be based solely on bilateral stress radiographs but should instead be made only after horizontal instability has been ruled out with appropriate imaging modalities. Otherwise, Rockwood type IV injuries or Rockwood type II injuries with concomitant horizontal instability may be overlooked.

Zusammenfassung

Hintergrund

Es herrscht Konsens, dass Rockwood II Verletzungen konservativ behandelt werden. Andererseits zeigen verschiedene Studien, dass einige dieser Patienten mittel- und langfristig persistierende Beschwerden behalten, u.a. durch eine horizontale Instabilität.

Patienten und Methoden

Patienten mit einer coraco-claviculären seit-zu-seit Differenz von bis zu 25% in der Panoramaaufnahme, die entweder eine posteriore Subluxation der lateralen Clavicula im axialen Röntgenbild oder im MRT (bei 8 Patienten) zeigten oder klinisch und radiologisch eine dynamisch posteriore Instabilität der lateralen Clavicula hatten, wurden in die Fallserie eingeschlossen. Andere Verletzungen des Schultereckgelenkes als Rockwood II Verletzungen oder Rockwood II Verletzungen ohne horizontale Instabilität wurden ausgeschlossen.

Ergebnisse

Zwischen 2015 und 2022 erfüllten 13 Patienten mit einem Durchschnittsalter von 30,7 Jahren (21 bis 48 Jahre) diese Kriterien. Acht Patienten hatten nach weiterführender Diagnostik eine statisch posteriore Subluxation der lateralen Clavicula im Sinne einer Rockwood IV Verletzung. Fünf Patienten hatten eine dynamisch posteriore Instabilität. Alle Patienten hatten auswärtig auf Basis der belasteten Panoramaaufnahme eine Empfehlung zur konservativen Therapie erhalten.

Schlußfolgerung

Die Diagnose einer Rockwood II Verletzung sollte nicht alleine auf der Basis der belasteten Panoramaaufnahme gestellt werden, sondern erst nach Ausschluß einer begleitenden horizontalen Instabilität mittels entsprechender Bildgebung. Ansonsten kann eine Rockwood IV Verletzung oder eine Rockwood II Verletzung mit begleitender horizontaler Instabilität übersehen werden

Keywords

Acromio-clavicular joint separation - horizontal instability AC joint - dynamic horizontal instability AC joint - Rockwood II injur

Schlüsselwörter

Akromioklavikulargelenksverletzung - horizontale Instabilität AC-Gelenk - dynamisch horizontale Instabilität - Rockwood II Verletzung

Publication History

Received: 05 October 2024

Accepted after revision: 06 July 2025

Article published online:
23 September 2025

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