Relationship between the maximum flexion-internal rotation test and the torn acetabular labrum of a dysplastic hip.

To determine the relationship between pain at flexion-rotation and the status of a labral tear in patients with dysplastic hips, physical examination maneuvers and hip arthroscopy were carried out in 59 patients with dysplastic osteoarthritis (5 men and 54 women; mean age, 41 years; range, 16 to 64 years). Between January 1998 and June 2000, these patients underwent 60 hip arthroscopies at Kyushu University Hospital. All hip joints arthroscoped demonstrated incomplete or complete detaching tears of the acetabular labrum in one portion of the weight-bearing area. Twenty-three patients (39%) experienced pain during the maximum flexion-internal rotation test; 16 patients (27%) showed a positive result for the maximum flexion-external rotation test. There was no statistically significant relationship between the results of the maximum flexion-external rotation test and the arthroscopic findings of labral tears. A positive maximum flexion-internal rotation test result, however, correlated well with incomplete detaching tears in the posterosuperior portion of the acetabular labrum. In contrast, a complete detaching tear of the posterosuperior labrum was associated with a negative maximum flexion-internal rotation test result. The maximum flexion-internal rotation test is useful for assessing the magnitude of a labral tear in the posterosuperior portion of the acetabular labrum in dysplastic hips.