Table 1. Intraoperative classification of the acetabular transverse ligament (ATL) according to Archbold ⁴ .

Grade of ATL	Appearance of ATL visualized during THA
1	Normal quality ATL visible at the acetabulum exposure
2	ATL covered by soft tissue which has to be removed to expose the ligament
3	ATL covered by osteophytes which have to be removed to expose the ligament
4	Ligament not identified, even after proper removal of osteophytes or soft tissue