Subtrochanteric Femoral Fracture Fixation

Indication. A displaced subtrochanteric femoral fracture — within 5 cm distal to the lesser trochanter — in an adult. Virtually all displaced fractures in this region are fixed surgically, because the powerful deforming forces and the high bending stresses at this level make non-operative treatment predictably fail. Absolute indications - Any displaced subtrochanteric femoral fracture in an adult

• An open subtrochanteric fracture, after wound debridement and antibiotic therapy
• Polytrauma with a femoral shaft or subtrochanteric fracture — early fixation for damage control and mobilisation
• A pathological subtrochanteric fracture from metastatic disease — stabilisation for pain relief and mobilisation
• An impending pathological fracture (a cortical breach of 50 percent or more with pain) — prophylactic fixation before completion Relative indications - An atypical bisphosphonate-related subtrochanteric fracture with prodromal pain and radiographic cortical changes — prophylactic cephalomedullary nailing to prevent completion
• A non-united subtrochanteric fracture after previous failed fixation — revision with exchange nailing or plate augmentation
• A periprosthetic fracture around a well-fixed femoral stem with subtrochanteric extension — implant-specific strategies Contraindications. Absolute: a patient unfit for anaesthesia because of severe medical comorbidity or terminal illness where the burden of surgery exceeds the benefit; and active deep infection at the surgical site (a contaminated open fracture is a different scenario, treated in staged fashion). Relative: very poor bone stock with no restorable medial cortex — consider a plate-based construct with medial augmentation or a megaprosthesis in the elderly; and an ipsilateral femoral neck fracture with subtrochanteric extension, which may need separate cervical fixation or a reconstruction nail with separate neck-screw capability. The implant decision. Every subtrochanteric fracture is reduced first; the implant is chosen second, driven by whether the piriformis fossa is intact:

Consent specifically for infection (1 to 3 percent), malreduction (5 to 10 percent), nonunion (5 to 15 percent), implant failure (2 to 8 percent), iatrogenic fracture during surgery (1 to 3 percent), the possible need for revision surgery, blood transfusion, and later hardware removal. Setup. Supine on a radiolucent fracture table (or a flat-top table with a femoral distractor), with a well-padded perineal post providing counter-traction. General or regional anaesthesia — regional anaesthesia lowers the pulmonary complication risk in the elderly with chest injury or comorbidity. A single dose of intravenous cefazolin 2 g at induction (redose if the operation exceeds 4 hours). Confirm full AP and lateral fluoroscopy of the fracture, the entry point and the distal femur before draping.

The goal: restore length, rotation and alignment by opposing the characteristic apex-anterolateral deformity, then stabilise the fracture with a long cephalomedullary nail that shares load with the restored medial cortex. The exposure is a percutaneous muscle-splitting approach to the entry point — laid out as the first steps below — and the whole operation turns on correcting the deformity and the entry point before any reaming.

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Weight-bearing progression Weight-bearing depends on fracture pattern, bone quality, the implant construct and the quality of reduction.

Immediate post-operative care. Multimodal analgesia (paracetamol, NSAIDs if not contraindicated, a short opioid course, and a femoral or adductor-canal block); chemical VTE prophylaxis (low-molecular-weight heparin or a factor Xa inhibitor) for 2 to 6 weeks, extended to 4 to 6 weeks with additional risk factors; passive and active-assisted hip and knee range-of-motion from day 1; wound inspection at 48 hours with suture or staple removal at 10 to 14 days. Follow-up schedule. Review at 2 weeks (wound check and radiographs), 6 weeks (early callus, alignment, implant position), 3 months (progression of union, adjust weight-bearing), 6 months (confirm union or catch delayed union early), and 12 months (confirm union; discuss hardware removal if symptomatic). Complications

Definition and epidemiology. The subtrochanteric region extends from the lesser trochanter to 5 cm distal to it. It is one of the most mechanically demanding zones in the skeleton: the powerful muscular attachments to the proximal femur create characteristic displacements, and the high bending forces here make non-union more common than in diaphyseal femur fractures. Subtrochanteric fractures account for a significant subset of proximal femoral fractures and occur in two broad groups — young patients after high-energy trauma and elderly patients after low-energy falls, the latter increasingly complicated by osteoporosis and bisphosphonate use. Deforming forces. The powerful muscular attachments to the proximal femur create the characteristic displacement that must be understood and deliberately corrected before fixation. | Muscle group | Action on the proximal fragment | Clinical effect | |---|---|---| | Iliopsoas (lesser trochanter) | Flexes the proximal fragment | Apex angulates anteriorly | | Gluteus medius and minimis (greater trochanter) | Abduct the proximal fragment | Proximal fragment translates laterally and superiorly | | Piriformis, obturator internus, gemelli | Externally rotate the proximal fragment | Proximal fragment rotates laterally, combined with flexion and abduction | | Adductors (longus, brevis, magnus) | Pull the distal fragment medially | Distal fragment translates medially | | Quadriceps (mainly vastus lateralis) | Extensor mechanism pulls the distal fragment | Distal fragment tends to extend | Net deformity. The proximal fragment is flexed, abducted and externally rotated; the distal fragment is adducted and relatively extended. The fracture line angulates with its apex pointing anterolaterally — hence "apex-anterolateral angulation." Russell-Taylor classification. The Russell-Taylor classification (1986) guides implant selection based on whether the piriformis fossa and the lesser trochanter or medial cortex are involved. Type I fractures allow a standard piriformis-entry nail, which gives the best biomechanical axis; Type II fractures destroy the piriformis fossa and require a trochanteric-entry nail or a plate. The sub-classification by lesser trochanter involvement reflects medial-cortex integrity — Type IB and IIB fractures have medial disruption and higher nonunion rates.

Anatomical landmarks. The greater trochanter is the entry point for trochanteric-entry nails — palpable as the most proximal lateral prominence, with the correct point at the very tip, slightly medial, colinear with the shaft axis on AP. The piriformis fossa, at the base of the greater trochanter just medial to its tip, is the entry for a standard antegrade nail and is intact only in Type I fractures. The lesser trochanter is the iliopsoas insertion; its detachment or comminution (Type IB, IIB) signals loss of the medial cortical buttress. The calcar femorale is the vertical dense bone of the posteromedial femoral neck extending into the medial subtrochanteric cortex — the primary load-bearing surface of the proximal femur; losing it dramatically increases the bending moment on any implant. Vascular anatomy. The medial femoral circumflex artery (the dominant head blood supply in most people) runs along the inferior border of obturator externus then posterior to the neck, and is at risk in open medial approaches — avoid excessive medial dissection. The ascending branch of the lateral femoral circumflex artery runs along the intertrochanteric line anteriorly; the deep branch is encountered along the lateral shaft during a plate approach. Large perforating branches of the profunda femoris cross the medial shaft and are at risk during open medial approaches or excessive cerclage passage. Biomechanics. The subtrochanteric femur sees compressive loads estimated at 3 to 4 times body weight in normal gait and significantly more on stair climbing. The medial cortex bears roughly 60 to 70 percent of the compressive load; the lateral cortex bears tensile stress. Loss of medial support shifts load to the implant — a plate then acts as a tension band and is vulnerable to cyclical bending failure, while an intramedullary nail remains load-sharing. The lever arm from the femoral head to the fracture creates large bending moments — the more proximal the fracture, the higher the bending stress at the fracture-implant interface. Implant-selection evidence. Cephalomedullary nailing is load-sharing, minimally invasive, and biomechanically superior under cyclic loading, with proximal cephalic locking screws and distal interlocking. The 95-degree blade plate offers fixed-angle fixation and direct visualisation for anatomical reduction but needs more dissection and has higher blood loss and infection risk. The dynamic condylar screw is similar, with a compression barrel, and suits more distal patterns.

Special scenario — atypical bisphosphonate-related fractures. The American Society for Bone and Mineral Research (ASBMR) defined atypical femoral fractures (Shane et al., 2010). Major features: a subtrochanteric or diaphyseal location, prodromal deep thigh or groin pain (days to weeks before fracture), minimal or no trauma, a transverse or short oblique pattern, medial cortical spiking, and minimal comminution. Minor features: lateral cortical thickening (periosteal reaction or beaking), bilateral involvement, and delayed healing. Management is to stop the bisphosphonate, consider teriparatide, optimise calcium and vitamin D, and involve endocrinology. Cephalomedullary nailing is the fixation of choice — load-sharing and biological, with distal locking; plating has a substantially higher failure rate in this transverse pattern with poor cortical contact. Expect slower healing and protect weight-bearing for 3 to 6 months after a completed fracture. When prodromal pain persists and a cortical breach reaches 50 percent or more, prophylactic cephalomedullary nailing prevents a completed fracture and carries lower morbidity than fixing a displaced fracture; a breach of less than 50 percent without pain is monitored with serial radiographs and a drug holiday. Special scenario — pathological subtrochanteric fractures. The proximal femur is a common site for skeletal metastases (breast, prostate, lung, renal and thyroid primaries). Stabilise for pain control and mobilisation with a full-strength cemented cephalomedullary nail when the canal is intact and proximal bone stock suffices; consider endoprosthetic reconstruction when the proximal bone is destroyed beyond salvage; give postoperative radiotherapy (typically 20 to 30 Gy in 5 to 10 fractions) to control tumour progression; and involve oncology, radiation oncology and palliative care.