Osseoscopy: Direct Visualization to Assist Core Decompression and Debridement of Necrotic Bone Defects  William C. Geisert, M.D., Aaron M. Perdue, M.D., Kagan Ozer, M.D.  Arthroscopy Techniques  Volume 6, Issue 3, Pages e607-e612 (June 2017) DOI: 10.1016/j.eats.2017.01.004 Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 1 Standard setup in operating room. The patient is placed in the lateral decubitus position on the table. The operating table allows passage of the C-arm underneath to perform core decompression of the femoral head. Once core decompression has been performed, the arthroscopy tower is placed on the opposite side of the table to allow direct visualization. Arthroscopy Techniques 2017 6, e607-e612DOI: (10.1016/j.eats.2017.01.004) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 2 Radiographs taken from the same patient placed in the lateral decubitus position on the operating table. (A) On the anteroposterior view, a pin entry site is chosen at a level just proximal to the anterior border of the lesser trochanter. The pin is advanced in a proximal and medial direction toward the area of the necrotic lesion (arrows) in the femoral head. (B) A lateral image is obtained to verify that the guide pin is centered in the femoral neck and the pin is advanced into the lesion. (C) Once entry is made, a cavity to receive the graft is fashioned. Reaming is continued over the guidewire to the level of the lesion. The image shows a 10-mm reamer placed through the guidewire, reaming through the necrotic area of the bone (arrows). (D) The cavity is reamed to a diameter sufficient to receive the fibular graft while care is taken to ensure that the cortex of the femoral neck is not breached. An 18-mm reamer within the canal is shown. Throughout this procedure, the patient is placed in the lateral decubitus position with the C-arm arching over the patient, obtaining anteroposterior and lateral (frog-leg) views of the affected hip. Arthroscopy Techniques 2017 6, e607-e612DOI: (10.1016/j.eats.2017.01.004) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 3 The patient is placed laterally on the operating table with the left hip exposed. (A) During osseoscopy, Charnley-type adjustable retractors (arrows) are used to expose the entry point to the bone. The lower extremities are at the top of the picture. (B) For osseoscopy, we construct a plug to restrict outflow at the entrance of the cavity at the lateral femoral cortex. The sponge is opened and folded to form a strip of 2 to 3 cm. This strip of fabric is wound around the inflow-outflow cannula at a level matching the level of the lateral femoral cortex with the arthroscope fully inserted into the cavity. (C) The patient is lying laterally on the right hip. The left hip is exposed. His feet are located at the bottom of the picture. The cannula and arthroscope are inserted into the cavity (arrow) with the fabric ring entering just past the lateral femoral cortex. This works as a partial seal preventing unrestricted outflow of irrigation from the cavity and allowing for positive intracavity pressure to aid in visualization, as well as decreasing the amount of irrigation required for the procedure. The arthroscope can be moved in and out freely with the plug in place. (D) Excess perfusate outflow is collected in a sterile pouch (arrows). Arthroscopy Techniques 2017 6, e607-e612DOI: (10.1016/j.eats.2017.01.004) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions

Fig 4 The patient is placed laterally on the operating table with the left hip exposed. The yellow arrows mark the direction of the patient's head. (A) An entirely necrotic area is shown on a close-up view. (B) In the same patient, normal bone is juxtaposed with the necrotic area. The white arrows mark the zone between healthy and necrotic bone segments. (C) Close-up view of the necrotic area being removed with a curette. The white arrow marks a loose piece of necrotic bone. Arthroscopy Techniques 2017 6, e607-e612DOI: (10.1016/j.eats.2017.01.004) Copyright © 2017 Arthroscopy Association of North America Terms and Conditions