Adequate surgical exposure is essential in successful revision hip surgery and ETO can be a useful tool in achieving that for the appropriate indications. An ETO in revision THA can be used to provide access to the femoral implant removal, enhance exposure of the acetabulum and correct any varus deformity in un-cemented femoral revision. This has the added advantage of keeping the soft tissue proximally and distally uncompromised [1].
Revision of the femoral stem is indicated in failed primary hip replacement, single stage or 2-stage revision of infected hip replacement, and in revision of failed proximal femoral fracture fixation. Revision with posterior approach is often preferable due to its extensile exposure even with a previous lateral approach. This avoids further damage to the gluteus medius and minimus, and in revision of failed femur fixation it allows full exposure and hip dislocation prior to removal of metal work [2].
Younger described series of Paprosky’s extended proximal femoral osteotomies (EPFO), later named ETO, and advocated its use in revision surgery. EPFO technique was described for removal of distally fixed femoral components. The anterolateral proximal femur is cut on one third of its circumference, extended distally and levered on the anterolateral hinge of the periosteum and muscle, creating an intact muscle osseous sleeve. ETO is composed of greater trochanter and anterolateral femoral diaphysis along with preserved gluteus medius and vastus lateralis attachments as described by Younger and Paprosky [3]. It was performed via the posterolateral approach. The surgical equipment described in the preoperative planning schedule includes explant tools, trephines, high speed burrs, flexible osteotomes, and ultrasonic cement removal instruments to aid cemented stem removal. Finally, the ETO can be made after dislocation and stem removal in infection cases for thorough debridement of the canal or in loose femoral stem cases with proximal varus remodelling for better access to distal femur [4].
The anterolateral aspect of the proximal femur is cut with an oscillating saw, and then multiple pencil burr drill holes on the osteotomy lines are connected using an osteotome. The anterior soft tissue is left undisturbed with this controlled fracture through the perforated holes.
When using the technique of cemented impaction, allograft at the distal femoral osteotomy site with cancellous bone is associated with high union rate at a mean of 6 months. Care must be taken to ensure that extrusion of cement does not occur to allow unimpaired bone healing in cemented polished prosthesis at revision THA with ETO [5].
Postoperatively, femoral revision may be treated with protected partial weight bearing (30% weight bearing) for the first 6 weeks. After 6-8 weeks, patients can weight-bear as tolerated, but typically avoid active abduction for 6-12 weeks until radiographic union of the osteotomy [6].
Revision THA with ETO is associated with lower stem subsidence rate and less cortical perforation compared to revision THA without ETO [7].
We reviewed our minimum 2-year results of ETO for femoral revision focusing on radiological and clinical outcomes.
We also conducted a systematic review to look at the objective outcomes of ETO, including union rate, infection eradication rate, subsidence and proximal GT migration in the setting of revision THA for prosthetic joint infections, aseptic loosening and periprosthetic fractures. To our knowledge, this is the first systematic review to look at the outcomes in all the three categories mentioned.
