# Subtrochanteric Femur Fracture > Subtrochanteric femur fracture for NEET-PG Orthopaedics, covering deforming forces, Seinsheimer and Russell-Taylor classes, and why nails beat plates here. - Canonical URL: https://prepelephant.com/topics/neet-pg/orthopaedics/subtrochanteric-femur-fracture - Exam / course: NEET-PG · Subject: Orthopaedics - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-14 - Last updated: 2026-10-14 - Reference basis: Apley's System of Orthopaedics and Fractures; Campbell's Operative Orthopaedics; Rockwood and Green's Fractures in Adults - How to cite: "Subtrochanteric Femur Fracture", PrepElephant, https://prepelephant.com/topics/neet-pg/orthopaedics/subtrochanteric-femur-fracture ## Direct answer A subtrochanteric femur fracture is a break of the proximal femur between the lesser trochanter and a point about 5 cm below it. The iliopsoas, abductors and adductors pull the fragments out of line, and the high bending loads in this zone make an intramedullary nail the preferred fixation in most adults. ## What you must remember - **Location:** the fracture lies between the lesser trochanter and about 5 cm distal to it, an area of dense cortical bone that carries high mechanical stress. - **Deforming forces:** the iliopsoas flexes and externally rotates the proximal fragment, the abductors abduct it, and the adductors draw the distal fragment up and in, causing shortening. - **Mechanism:** high-energy trauma in young adults, or a low-energy fall in older patients, where long-term bisphosphonate use is linked with atypical subtrochanteric fractures. - **Seinsheimer classification:** grades the fracture by fragment number, displacement and lesser trochanter involvement, with types I to V in the commonly taught scheme. - **Russell-Taylor classification:** asks whether the fracture extends into the piriformis fossa, which guides the nail entry point and the choice of implant. - **Preferred implant:** a long intramedullary nail, which sits near the mechanical axis, shortens the lever arm and avoids the wide stripping a lateral plate needs. - **Reduction goal:** restore length, alignment and rotation, and avoid varus, which predisposes to nonunion and implant failure. ## A stepwise approach from fracture pattern to nail A 40-year-old motorcycle rider presents with a subtrochanteric fracture after a high-speed crash. The steps below show the order in which an examiner expects the case to be reasoned through, from imaging to follow-up. 1. **Image the whole femur.** Take AP and lateral views of the entire femur and the hip, because the fracture line may extend further than the initial films suggest and the other hip needs assessment. 2. **Define the pattern.** Use the Seinsheimer and Russell-Taylor classifications to record the number of fragments, the displacement and any extension into the piriformis fossa. 3. **Note the deforming forces.** The proximal fragment flexes, abducts and externally rotates under iliopsoas and abductor pull, while the distal fragment shortens and adducts. 4. **Choose the implant.** A long intramedullary nail, entered through the piriformis fossa or the greater trochanter depending on the pattern, is the usual choice, and a fixed-angle plate is kept for selected cases where a nail cannot be used. 5. **Reduce and fix.** Apply traction on a fracture table or a radiolucent table, restore length, alignment and rotation, then insert the nail and lock it proximally and distally. 6. **Follow up for healing.** Watch serial radiographs for nonunion, varus collapse and cut-out of the proximal screws, and review the bisphosphonate history if the fracture was atypical. ## Where the exam tries to catch you Subtrochanteric questions usually test whether the candidate recognises the high-stress zone and the deforming forces. - **Trap:** choosing a dynamic hip screw because the fracture is "near the hip." **Correct:** the fracture lies below the lesser trochanter in a high-stress zone, where a long nail is the preferred fixation. - **Trap:** treating a subtrochanteric fracture in a long-term bisphosphonate user as an ordinary fall. **Correct:** it may be an atypical femoral fracture, so the contralateral femur should be imaged and the drug history reviewed. - **Trap:** treating Seinsheimer and Russell-Taylor as the same system. **Correct:** Seinsheimer grades the fragment pattern, while Russell-Taylor focuses on the piriformis fossa and lesser trochanter, which guides the implant. ## Frequently asked questions ### Where exactly is a subtrochanteric femur fracture located? A subtrochanteric femur fracture lies between the lesser trochanter and about 5 cm distal to it. It is distinct from an intertrochanteric fracture, which lies between the greater and lesser trochanters. ### Why are intramedullary nails preferred for subtrochanteric femur fractures? Intramedullary nails are preferred because they sit near the mechanical axis of the femur, which shortens the lever arm and carries load along the bone. They also avoid the wide soft tissue stripping that a lateral plate needs in this high-stress zone. ### Which deforming forces shorten a subtrochanteric femur fracture? The iliopsoas flexes and externally rotates the proximal fragment, and the abductors pull it into abduction. The adductors draw the distal fragment up and in, producing the shortening that reduction must overcome. ### What does the Russell-Taylor classification decide? The Russell-Taylor classification in subtrochanteric femur fractures asks whether the fracture extends into the piriformis fossa and how the lesser trochanter is involved. It helps the surgeon choose the nail entry point and decide between a piriformis entry nail and a fixed-angle device. ### What complications follow fixation of a subtrochanteric femur fracture? Complications after fixation of a subtrochanteric femur fracture include nonunion, varus collapse, cut-out of the proximal screws and implant breakage. Careful reduction, adequate proximal locking and early mobilisation reduce these risks.