The Direct Anterior Approach to Hip Reconstruction

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Role of Fluoroscopic Imaging and Image Guidance Preetesh D. Patel, Preston W. Grieco, Jeremy M. Gililland, and Trevor M. Owen

it is necessary to move that individual before bringing in the unit to obtain imaging. Standard plastic draping of the unit is used; however, it is helpful to add additional sterile draping over the body of the unit to prevent contamina tion of the side of the surgical field. The latch allowing the unit to be rolled to the lateral view is not needed and thus can be covered with this draping. The unit is positioned perpendicular to the patient and can be tilted cranially or caudally to adjust for pelvic tilt. Specialized tables such as the Hana table (Mizuho OSI) can easily accommodate a fluoroscopic unit. However, if using a standard operating room table, one must ensure that the base of the table is positioned such that it does not interfere with the path of the unit and an acceptable pelvis image can be obtained. Other equipment such as electrocautery and suction can be placed at the proximal aspect of the patient on the non operative side to minimize their interference. Technical Tips for Fluoroscopy Image intensifiers can be used throughout the DAA THA surgical procedure to confirm or improve on surgi cal steps. This can be performed with or without special surgical tables or attachments based on surgeon prefer ence. The key steps on how to properly incorporate fluo roscopy to the DAA THA are as follows. Before the procedure, the patient’s leg length discrep ancy (LLD) is assessed. The medial malleoli can be used as a reference and have been established as a valid and reliable landmark for measure. 1 True leg length is a complex interaction between soft tissues, bones, and implants. One must consider any knee and hip contrac tures as well as spinal deformity with subsequent pelvic obliquity when determining the true LLD. The physi cal assessment can then be compared with the patient’s perceived LLD, and a planned limb length correction is formulated. It is our routine practice to ask the patient before surgery of any perceived LLD. Preprocedural Physical Assessment of the Patient’s Leg Length Discrepancy

Key Learning Points ◆ Understand the use (including advantages and limitations) of fluoroscopic imaging and image guidance during a direct anterior approach (DAA) in total hip arthroplasty (THA). ◆ Identify pitfalls as well as tips and tricks when utilizing fluoroscopic imaging. Introduction Accurate component positioning is of the utmost impor tance in THA. Malpositioned implants can lead to dis location, impingement, wear, and early failure. One frequently discussed advantage of the DAA in the supine position is the ease with which fluoroscopic imaging can be used to aid in component positioning, component sizing, assessment of leg length, and offset and to iden tify intraoperative complications such as canal perfora tion or fracture. This visual feedback is provided in real time, and adjustments can be made to improve the final implant position. With the patient in a supine position on a radiolucent table, the pelvis and hip are in an ideal position to obtain routine anteroposterior (AP) imaging with minimal interference from the fluoroscopy unit. This contrasts with procedures performed in the lateral position where the pelvis can roll forward or backward and imaging requires the fluoroscopy unit to be rotated 90°, leading to difficulty accessing the operative field. Equipment and Operating Room Setup Fluoroscopy units come in many configurations and sizes with common image intensifier sizes of 9 and 12 in. We recommend using the larger 12-in units because these will typically allow the surgeon to visualize the entire pelvis on the AP view, providing the most data for the assessment of component positioning, leg length, and offset. Patients with a large body habitus may limit the ability to obtain a full AP pelvis even on the larger units because the image intensifier cannot be brought close enough to the pelvis without impinging on soft tissue. Similarly, anteriorly placed retractors can also limit the ability to bring the unit low enough to obtain the desired view and obscure the hip as well. The fluoroscopy unit is positioned on the nonoperative side of the patient and can be brought in over the patient, limiting interference with the surgical team. If an assistant is used on this side of the table (ie, the nonoperative side),

Preprocedural Fluoroscopy (Pelvic Tilt, Pelvic Rotation, and Leg Length) Once the patient is positioned on the preferred operat ing table, fluoroscopy is performed. An AP pelvis image Copyright © Wolters Kluwer, Inc. Unauthorized reproduction of the content is prohibited. 2024

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