Table 2.

Classification of limitations in range of movement (ROM) of the hip joint according to Tönnis [12]

	Criteria
Grade 0	No limitation in ROM, flexion > 120°, ab-/adduction and internal/external rotation > 40°, extension at least 0°
Grade 1	Flexion 110°, extension 0°, ab-/adduction and internal/external rotation 20–30°
Grade 2	Flexion 100°, lack of extension 10–15°, internal rotation 0–20°, abduction 0–10°
Grade 3	Flexion < 100°, external rotation contracture 10–20°, add- or abduction contracture 10–20°
Grade 4	Contracture more pronounced than in grade 3

In case of doubt the amount of the flexion-extension movement takes precedence over the other movement directions