Screw Fixation of Os Acetabuli: An Arthroscopic Technique Adrián Cuéllar, M.D., Xabier Albillos, M.D., Asier Cuéllar, M.D., Ricardo Cuéllar, M.D., Ph.D.  Arthroscopy Techniques  Volume 6, Issue 3, Pages e801-e806 (June 2017) DOI: 10.1016/j.eats.2017.02.012 Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 1 Plain anteroposterior radiograph showing center-edge (CE) angles. The left hip has a 36° CE angle including the os acetabuli (solid red lines) and a 19° CE angle excluding the os acetabuli (red dashed line). The right hip has a 35° CE angle (yellow lines). (L, left; R, right.) Arthroscopy Techniques 2017 6, e801-e806DOI: (10.1016/j.eats.2017.02.012) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 2 Computed tomography views showing os acetabuli (arrows) in left hip: axial view (A), coronal view (B), and 3-dimensional reconstruction (C). Arthroscopy Techniques 2017 6, e801-e806DOI: (10.1016/j.eats.2017.02.012) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 3 Achieving bone-to-bone contact (lateral portal view with 30° arthroscope in left hip). (A) Detachment of the os acetabuli (OA) from the acetabular rim with a curette from the anteromedial portal. (B) OA footprint in the acetabular rim (Ar) with the subchondral bone exposed. (lcs, lateral capsule side.) Arthroscopy Techniques 2017 6, e801-e806DOI: (10.1016/j.eats.2017.02.012) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 4 Os acetabuli (OA) fixation with guided headless screw. A view of the left hip is shown through a 30° arthroscope in the lateral portal. The fixation instruments are inserted through the accessory lateral portal. (A) A 1.7-mm crown-tip inline drill (arrow) is used for reduction. (B) Insertion of guidewire (arrow) through arthroscopic control. (C) Radiograph showing proper guidewire orientation (arrow). (D) The guidewire (arrow) penetrates through the OA and the footprint. (Ar, footprint in acetabular rim; lcs, lateral capsule side.) Arthroscopy Techniques 2017 6, e801-e806DOI: (10.1016/j.eats.2017.02.012) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 5 Fixation of os acetabuli (OA) with a screw. A view of the left hip is shown through a 30° arthroscope in the lateral portal. (A) The cannulated screw (arrow) is introduced, and compression of the OA against the acetabular rim is assessed. (Ar, footprint in acetabular rim; lcs, lateral capsule side.) (B) Radiograph after insertion of the screw (arrow). Arthroscopy Techniques 2017 6, e801-e806DOI: (10.1016/j.eats.2017.02.012) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 6 Final arthroscopic assessment (lateral portal view with 30° arthroscope in left hip). The os acetabuli (OA) has been fixed with the screw. To repair the labral tear, 1.7-mm Suturefix XL suture anchors (arrows) are placed on the acetabular rim in the 11- to 12-o'clock position. (Fe, chondral surface of femoral head; La, labrum.) Arthroscopy Techniques 2017 6, e801-e806DOI: (10.1016/j.eats.2017.02.012) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 7 Axial radiographic view of the left hip showing proper fixation of the os acetabuli (OA) (arrow) 3 months after surgery. Arthroscopy Techniques 2017 6, e801-e806DOI: (10.1016/j.eats.2017.02.012) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions