[Isolated avulsion fracture of the lesser tuberosity of the humerus. Apropos of a case].

PURPOSE OF THE STUDY

The authors report a rare case of an isolated avulsion fracture of the lesser tuberosity of the humerus in an adult. The aim of the study was to highlight diagnostic features as well as surgical treatment.

MATERIAL

A 31 year old woman presented an isolated avulsion fracture of the lesser tuberosity of the humerus. Physical exam, standard radiographs of the shoulder as well as a computed tomographies (CT) were obtained.

METHODS

An assessment was made of the patient's complaints, signs and symptoms, diagnosis, surgical treatment, physical therapy and follow-up. Final clinical results were evaluated according to external rotation and muscular strength of the shoulder.

RESULTS

The diagnosis was evoked on standard radiographs of the shoulder and confirmed by CT. The patient was operated on the 8th day following trauma and pendular physical therapy was initiated on the third day postoperatively. The patient recovered her daily activities from the 6th week and was back at work by the end of the 2nd month. Follow up at 12 months showed a painless shoulder with external rotation at 50 degrees in adduction and 70 degrees in abduction. Muscular strength was identical to the contralateral side. No antero-medial impingement was detected due to the hardware.

DISCUSSION

This observation illustrates the rare aspect of this fracture, already recognized in literature. The fracture mechanism remains unknown. We agree with Haas, Ross and Love that it might be due to a forced external rotation of the shoulder at 60 degrees of abduction. We highlight the role of the "axillary view" and of the magnetic resonance imaging (MRI) in the diagnostic approach. Treatment is surgical by open reduction and internal fixation of the detached fragment.

CONCLUSION

Treatment must be surgical whenever there is a slight displacement of the detached fragment, to prevent non union, mal union or an antero-medial impingement that might limit mobility and muscular strength.