Extended Trochanteric Osteotomy for Femoral Revision





CASE STUDY


A 50-year-old man with no significant medical history underwent primary left total hip arthroplasty (THA) 9 years earlier. He returned to the medical office with a new limp and pain in his left hip that had increased during the past month. His postoperative course was previously uncomplicated, and he did not report any constitutional symptoms or recent illnesses.


Radiographs of the hip demonstrated a loose, cementless acetabular component and a well-fixed, fully porous-coated stem ( Fig. 52.1 ). The workup for infection was performed, including laboratory tests and synovial fluid aspiration. Based on the white blood cell count and positive aspirate cultures from the synovial fluid, he was diagnosed with a chronic periprosthetic hip infection.




FIGURE 52.1


A and B, Radiographs of an infected total hip arthroplasty. The cementless acetabular shell appears loose, but the fully porous-coated femoral stem is well fixed and ingrown.


A two-stage revision THA was planned. An extended trochanteric osteotomy was used during the first stage to facilitate removal of a well-fixed, fully porous-coated femoral stem ( Fig. 52.2 ). An articulated, antibiotic-loaded spacer was placed, and the second-stage revision was planned for a later date.




FIGURE 52.2


A and B, Postoperative radiographs obtained after an extended trochanteric osteotomy show placement of an antibiotic-loaded spacer.




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Chapter Synopsis


The indications, surgical technique, complications, and outcomes are described for an extended trochanteric osteotomy (ETO), which is an invaluable tool in femoral revision surgery.


Important Points





  • Preoperative templating is done to determine the needed ETO length.



  • A shorter osteotomy makes stem removal and adequate fixation of the trochanteric fragment more difficult.



  • Because a longer osteotomy limits diaphyseal fixation of the revision stem, at least 4 to 6 cm of diaphyseal scratch-fit should remain after the ETO is complete.



Clinical/Surgical Pearls





  • The osteotomy fragment should be approximately one third of the circumference of the femur, and soft tissue attachments must not be stripped because of the risk of nonunion from devascularization.



  • The osteotomy can be performed in a controlled manner with a microsagittal saw, sagittal saw, or pencil-tip, high-speed bur.



  • After the posterior and distal portions are completed, the anterior hinge of the osteotomy can be started proximally and distally to ensure proper propagation of the anterior portion. Wide, flat osteotomes help to open this anterior hinge and decrease the risk of fracture of the osteotomy.



Clinical/Surgical Pitfalls





  • The cables used to secure the trochanteric fragment should remain distal to the vastus ridge to avoid fracture of the trochanteric fragment around the ridge. One cable may be used distal to the osteotomy site to prevent iatrogenic fracture propagation during stem insertion.



  • The trochanteric fragment must be contoured to lie flat on the new stem, preventing trochanteric fragment fracture as the cables are cinched tightly.





Introduction


The number of patients requiring revision total hip arthroplasty (THA) is growing, and the femoral revision can be complex and challenging. Possible problems include component loosening, implant failure, periprosthetic fracture, and infection. Issues such as poor host bone, osteolysis, and well-fixed, cementless and cemented stems needing removal may further worsen the situation.


The extended trochanteric osteotomy (ETO) is an important part of revision THA. The ETO is an osteotomy of the lateral one third of the femur, allowing access to the inner contents of the proximal femur for revision surgery while preserving the femoral diaphysis for stem fixation. Compared with other osteotomies of the greater trochanter (e.g., chevron, Charnley, or anterior trochanteric osteotomy; trochanteric flip; trochanteric slide), the ETO affords the most extensile exposure while keeping the abductor–vastus lateralis soft tissue sleeve intact. This technique is relatively straightforward to perform and easy to repair. It heals reliably and has a low complication rate.




Indications and Contraindications


An ETO has several indications:




  • Removal of a well-fixed, cementless stem, especially a fully porous-coated stem or extensively porus-coated, tapered stem



  • Removal of a well-fixed, cemented stem, especially a precoated stem or a rough-textured stem



  • Removal of a well-fixed, distal cement mantle or a long cement plug



  • Femoral revision with a proximal femoral deformity (i.e., varus remodeling)



  • Extensile acetabular exposure



  • Any of these indications in the face of periprosthetic fracture or infection



Relative contraindications for an ETO include the following:




  • Femoral revision using impaction grafting



  • Cemented femoral revision





Equipment


Several pieces of equipment are needed for an ETO:




  • Sagittal or microsagittal saw



  • Reciprocating saw



  • Pencil-tip, high-speed bur



  • Metal-cutting, high-speed bur



  • Multiple wide, flat osteotomes



  • Cerclage cables



  • Multiple Gigli saws



  • Femoral stem trephines



  • Cement removal tools (e.g., reverse curettes; thin, flexible osteotomes; taps)



  • Cable grip plate or claw (optional)



  • Strut allograft (optional)





Surgical Technique


Preoperatively, the surgeon should plan the distal extent of the osteotomy based on complete radiographs of the pelvis, hip, and femur. The osteotomy should be long enough to facilitate component or cement mantle extraction, which is the primary indication for an ETO. A shorter osteotomy decreases the length available for adequate fixation of the trochanteric fragment. However, the osteotomy should not be too long. Approximately 4 to 6 cm of femoral diaphysis (scratch-fit) distal to the ETO site should be preserved to allow adequate fixation of the fully porous-coated, cylindrical stem ( Fig. 52.3 ). With a fluted, tapered revision stem design (e.g., Wagner), the necessary amount of diaphyseal fit is less important but still must be considered. As measured from the tip of the greater trochanter, the osteotomy is at least 10 cm long and typically about 12 cm long.


May 29, 2019 | Posted by in ORTHOPEDIC | Comments Off on Extended Trochanteric Osteotomy for Femoral Revision
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