Fused hip conversion to total hip arthroplasty with the direct anterior approach: surgical technique on a regular surgical table under fluoroscopic guidance

Purpose: Conversion of a fused hip to a total hip arthroplasty (THA) is technically challenging due to the loss of anatomical references. Here, a reproducible technique using the direct anterior approach (DAA) with a regular surgical table under fluoroscopic guidance is described, which has several advantages over traditional such as lateral or posterior approaches.

Methods: There were reported 11 cases of ankylosis hip that were converted to THA using the same surgical technique protocol. Clinical and radiographic outcomes were recorded at 3.2 years of follow-up. A detailed preoperative evaluation was performed, including a pelvis radiological evaluation and magnetic resonance image (MRI) to assess the integrity of the periarticular soft tissue and flexor muscles.

Results: The DAA has considerable advantages, such as allowing more precise targeting during surgery, avoiding the risk of pseudoarthrosis due to the absence of a trochanteric osteotomy, preserving the abductors, and allowing an easier-to-use of intraoperative fluoroscopy due to the supine position. Besides, the use of a standard table reduces surgical time and allows assessment of limb length, hip stability, and impingement in all planes in an intraoperative dynamic range, which decreases postoperative complications.

Conclusion: Conversion from hip fusion to THA is a rare and complex procedure. The use of DAA with a standard table and fluoroscopy helps to avoid high complications since it allows a dynamic intra-operative examination of the range of motion to rule out impingements, reduces the risk of dislocation, and allows leg lengthening verification.