Introductory remarks
Surgical principle and objective
Advantages
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No muscular transection is needed in easy cases (exceptions: tensor release, distal or proximal extension of approach)
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Damage to periarticular soft-tissues can be minimized in some cases
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Primary skin incision can be used
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Easy orientation, for surgeons familiar with the DAA
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DAA-trained surgeons can use their favorite approach for revisions
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Supine positioning of the patient
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Easy intraoperative determination of leg length
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Easy application of intraoperative fluoroscopic control
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Good visualization of the anterior acetabulum if needed
Disadvantages
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Technically demanding procedure
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Posterior exposure of acetabulum is limited
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Potential complaints associated with lateral femoral cutaneous nerve lesions: meralgia, hypesthesia
Indications
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Aseptic loosening of cemented and uncemented stems
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Periprosthetic fracture
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Periprosthetic joint infection
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Malalignment of the stem
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Leg length discrepancy
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Impingement
Contraindications
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A draining sinus from another approach
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The need to remove a posterior acetabular plate in the same surgery
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The need to remove a custom-made implant, which was implanted through different approach
Patients information
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General surgical risks, e.g., thrombosis, infection, wound healing problems, postoperative hemorrhage
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Potential complications of revision surgery (infection, dislocation, neurological complaints, loosening, fracture, etc.)
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Potential numbness or a burning sensation in the anterolateral region of the thigh and, in the worst cases, dysesthesia or meralgia due to injury to the LFCN (lateral femoral cutaneous nerve)
Preoperative work up
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Templating of the femoral implant
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Select size, length and off-set of revision implant
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Preoperative aspiration of the hip joint and 14-day incubation of the culture to exclude infection as a possible cause of loosening of the prosthesis
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In case of suspected periprosthetic joint infection: joint aspiration, laboratory tests, clinical findings
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In aseptic cases: single shot intravenous antibiotic administration
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Intravenous administration of tranexamic acid, if not contraindicated
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Preparation of a cell saver. Autotransfusion
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Clipping of hair of the leg from the belly button to below the knee joint
Instruments and implants
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Curved Hohmann retractors (standard minimally invasive THA Hohmann retractors)
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Double-tipped Hohmann for femoral elevation
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Instruments for stem and if needed cement removal
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Standard revision stems
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In cases of periprosthetic joint infection: femoral spacer
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Cerclage wires, cables or plate in cases of periprosthetic fractures
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Traction table if surgeon also performs primary DAA with a traction table
Anesthesia and positioning
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General or spinal anesthesia depending on the length of estimated surgical time
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Supine position
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Antibiotic prophylaxis
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Free draping of operated limb in order to enable proper manipulation during exposure of the femoral shaft
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External rotation, adduction, and hyperextension of the operated leg should be provided throughout the entire surgery to guarantee good exposure for the femur
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Operated leg must be placed underneath the contralateral leg in order to have good exposure to the femur (Fig. 1)
Postoperative management
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Weight bearing and physical therapy protocols depending on the amount of femoral revision
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Anticoagulation therapy: low molecular weight heparin for 35 days after surgery
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Prophylaxis of periprosthetic ossifications for 10 days after surgery with nonsteroidal anti-inflammatory drugs
Errors, hazards, complications
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ETO (Extended trochanteric osteotomy): non-union rate of 2–7%, failure of an ETO can lead to abductor weakness, severe pain, gait abnormalities and loosening of the femoral component. Therefore, careful and gradual elevation of the osteotomy fragment should be performed to avoid a fracture of the fragment. In symptomatic patients, revision surgery with a cable grip system can be performed.
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Interbundle technique: Sensory nerve deficit of the lateral femoral cutaneous nerve (LFCN). Neuropraxia of the femoral nerve can occur in case too much traction is applied. In such a scenario, short-term follow-up with an electromyogram should be performed 10 days after the surgery. In cases of motoric deficits debridement of the femoral nerve might be considered.
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All approach extensions: numbness of the anterolateral thigh due to LFCN injury. Longitudinal extension of the DAA (Direct Anterior Approach) entails a higher risk of harming the LFCN. Lazy S‑type distal extension: reduced risk of jeopardizing the LFCN.