Magnetic resonance imaging in traumatic posterior hip dislocation.

OBJECTIVES

The objective was to report the ability of a magnetic resonance image to document the integrity of the obturator externus tendon after posterior hip dislocation as a potential predictor for preserved femoral head vascularity.

DESIGN

Retrospective radiographic and clinical pilot study.

SETTING

Level I trauma center.

PATIENTS/

PARTICIPANTS

Nineteen consecutive patients with traumatic posterior hip dislocation. OUTCOME EVALUATION: Intraoperative correlation of soft tissue damage and radiographic assessment of avascular necrosis of the femoral head 3 years postinjury.

METHODS

Magnetic resonance imaging performed in the acute phase of posterior hip dislocation. Correlation with intraoperative findings during surgical hip dislocation and with avascular necrosis 3 years postinjury.

RESULTS

The obturator externus tendon was intact in all cases with preserved femoral head vascularity. After a 3-year follow up, there were no cases of avascular necrosis.

CONCLUSION

In this small series of patients, posterior hip dislocation did not imply a tear of the obturator externus muscle. An intact obturator externus tendon suggests preservation of the deep branch of the medial femoral circumflex artery to the femoral head.