High-yield overview

Reamed antegrade intramedullary nailing of the femoral shaft and subtrochanteric femur | advanced

Surgical Imaging

Critical Danger Structures and Exam Traps

Medial Femoral Circumflex Artery — AVN Risk

Location: The deep branch of the medial femoral circumflex artery (MFCA) runs posterior to the femoral neck and supplies the femoral head via the lateral epiphyseal (retinacular) vessels. Its course brings it close to the piriformis fossa entry zone.

Risk: A piriformis or medially-placed start point can injure the MFCA, causing avascular necrosis of the femoral head — devastating, and the principal reason piriformis entry is contraindicated in the skeletally immature.

Hip Abductors / Gluteus Medius

Location: The gluteus medius and minimus insert on the greater trochanter; their tendons and the abductor muscle belly overlie a trochanteric or piriformis start point.

Risk: A piriformis approach passes THROUGH the abductor insertion and the deep external rotators, risking heterotopic ossification, abductor weakness and a Trendelenburg gait. Trochanter-tip entry is more abductor-sparing but still demands gentle reaming away from the insertion.

Subtrochanteric Deforming Forces

The trap: The proximal fragment of a subtrochanteric fracture is FLEXED (iliopsoas), ABDUCTED (gluteus medius/minimus) and EXTERNALLY ROTATED (short external rotators), producing VARUS and PROCURVATUM (apex-anterior) malreduction.

The fix: Reduce before reaming, use a trochanteric-entry nail, and have a low threshold for open/assisted reduction — clamp, blocking (Poller) screws, cerclage or a unicortical reduction plate.

Pudendal Nerve — Traction Table

Location: The perineal post of the fracture table presses against the pudendal nerve and perineum during longitudinal traction.

Risk: Excessive or prolonged traction against the post causes pudendal nerve palsy (genital/perineal numbness, erectile dysfunction) and perineal soft-tissue injury. Use a well-padded post, the minimum effective traction, and release traction periodically.

Reaming and the Lung (Fat Embolism)

Why different: Reaming raises intramedullary pressure and showers fat/marrow emboli into the venous system — a pulmonary insult that matters most in the patient with a chest injury or borderline physiology.

Implications: In the unstable/borderline polytrauma patient consider damage control (external fixation first); when nailing, lower intramedullary pressure with sharp reamers, slow advancement and adequate canal venting.

Varus / Medial Cortex Blow-out — Trochanteric Entry

Why different: A trochanter-tip start point is lateral to the canal axis. A straight (piriformis-design) nail forced down a trochanteric entry levers the shaft into varus and can blow out the medial cortex of the proximal fragment.

Implications: Match the implant to the entry — use a trochanteric-entry nail with the correct proximal bend; confirm a true lateral and AP that the start point is correct before reaming.

Mnemonic

E.N.T.R.YENTRY — Choosing and Making the Start Point

Mnemonic

S.A.F.E.N.A.I.LSAFE NAIL — Avoiding the Classic Complications

Surgical Indications

Absolute / Standard Indications

Femoral shaft (diaphyseal) fractures — reamed antegrade intramedullary nailing is the GOLD STANDARD for the adult femoral shaft fracture
Subtrochanteric femoral fractures — with an appropriate trochanteric-entry (cephalomedullary or long reconstruction) nail
Ipsilateral femoral shaft and neck fractures — femoral neck takes priority for fixation; shaft managed with a nail or retrograde/plate strategy depending on neck fixation
Pathological / impending pathological fractures of the femoral diaphysis (prophylactic stabilisation)

Relative Indications

Segmental femoral fractures (length-stable construct restoring alignment)
Selected distal-third shaft fractures (retrograde nailing or plating may be preferable closer to the knee)
Femoral shaft nonunion (exchange reamed nailing)

Contraindications

Absolute:

Active infection at the entry site or along the canal (without staged management)
Piriformis entry in the skeletally immature / adolescent femur (AVN risk via the medial femoral circumflex artery)

Relative:

The unstable / borderline polytrauma physiology (favours damage control orthopaedics — external fixation first)
Pre-existing femoral deformity or retained hardware preventing canal passage (consider plating)
Very distal or very proximal fracture extension where nail fixation is biomechanically poor

Timing — Early Total Care vs Damage Control Orthopaedics

Early Total Care (ETC)

Definitive reamed nailing within the first 24 hours benefits the STABLE, resuscitated patient (earlier mobilisation, fewer pulmonary complications, shorter ICU/hospital stay)

Damage Control Orthopaedics (DCO)

In the UNSTABLE or BORDERLINE patient (haemodynamic instability, severe chest injury, head injury, coagulopathy, hypothermia, lactate not clearing), temporary spanning EXTERNAL FIXATION limits the surgical "second hit"
The reaming process drives a systemic inflammatory and embolic load; staging definitive nailing until physiology is restored reduces the risk of ARDS and multi-organ dysfunction
Safe Definitive Surgery / early appropriate care: increasingly, the decision is driven by the patient's RESPONSE to resuscitation (lactate clearance, base deficit) rather than a fixed time window

Evidence Summary

Antegrade Femoral Nailing — Key Decisions and Evidence

Key Evidence

Trochanteric versus piriformis entry portal for the treatment of femoral shaft fractures

Level II

Ricci WM, Schwappach J, Tucker M, Coupe K, Brandt A, Sanders R, Leighton R • J Orthop Trauma

Clinical Implication: A trochanteric start point with a purpose-designed trochanteric nail gives union, alignment and function equal to piriformis entry, with less fluoroscopy and operative time — especially in the obese — making trochanteric entry a rational routine choice in adults.

Verify on PubMed (PMID 17106375)

Impact of intramedullary instrumentation versus damage control for femoral fractures on immunoinflammatory parameters (EPOFF Study Group)

Level II

Pape HC, Grimme K, van Griensven M, Sott AH, Giannoudis P, Morley J, et al. • J Trauma

Clinical Implication: Primary reamed nailing produces a measurable inflammatory second hit; damage control external fixation first, with delayed nailing once physiology is restored, minimises this insult in the borderline or high-risk polytrauma patient.

Verify on PubMed (PMID 12855874)

Reamed versus unreamed intramedullary nailing of the femur: comparison of the rate of ARDS in multiple injured patients

Level I

Canadian Orthopaedic Trauma Society • J Orthop Trauma

Clinical Implication: Reaming did not raise the ARDS rate in this RCT; combined with the established union benefit of reamed femoral nailing, reamed insertion remains the default, with unreamed reserved for the rare case where the pulmonary embolic load is judged a genuine concern.

Verify on PubMed (PMID 16825962)

Rotational malalignment after intramedullary nailing of femoral fractures

Level III

Jaarsma RL, Pakvis DFM, Verdonschot N, Biert J, van Kampen A • J Orthop Trauma

Clinical Implication: Malrotation is common (around a quarter of cases) and clinically silent on examination — set and confirm rotation against the uninjured limb intra-operatively (lesser trochanter profile, cortical step-sign) and use CT if malrotation is suspected.

Verify on PubMed (PMID 15289684)

The reconstruction locked nail for complex fractures of the proximal femur

Level IV

Kang S, McAndrew MP, Johnson KD • J Orthop Trauma

Clinical Implication: Complex proximal femoral fractures malreduce into varus if not anatomically reduced first — achieve and hold reduction (assisted if needed) before nailing, place proximal screws to subchondral bone, and select the construct to the injury pattern.

Verify on PubMed (PMID 8592257)

Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOAdvanced

CLINICAL PROMPT

"A 28-year-old man sustains an isolated closed left subtrochanteric femoral fracture in a motorbike crash. He is haemodynamically stable. You plan antegrade intramedullary nailing. Talk me through your entry point choice and how you will avoid malreduction."

PRACTICAL APPROACH

This is a subtrochanteric fracture in a stable, isolated patient, so I would proceed with early definitive antegrade intramedullary nailing — but subtrochanteric fractures behave very differently from diaphyseal fractures and I plan specifically to avoid the characteristic malreduction. **Entry point**: I would use a GREATER TROCHANTER TIP entry with a trochanteric-entry (cephalomedullary or long reconstruction-type) nail that has the appropriate proximal mediolateral bend. The trochanteric start point gives me a more proximal, biomechanically suitable construct for a proximal fracture and is more abductor-sparing. I would avoid a piriformis entry here — it is more technically demanding, damages the abductor insertion, and in a more proximal fracture a straight piriformis nail does not control the proximal fragment as well. **Anticipating the deformity**: The proximal fragment will be FLEXED by iliopsoas, ABDUCTED by the gluteus medius/minimus and EXTERNALLY ROTATED by the short external rotators, while the adductors pull the distal fragment medially. The net deformity is VARUS and PROCURVATUM (apex-anterior). If I simply ream and nail without controlling this, I will lock the fracture in varus and procurvatum. **Reduction strategy**: I REDUCE BEFORE I REAM. I would consider a free-leg (radiolucent table) set-up for rotational control, or a traction table with a well-padded perineal post. I have a low threshold for assisted reduction: a percutaneous clamp or ball-spike pusher, BLOCKING (Poller) screws placed to push the nail away from the apex of the deformity, cerclage for a long spiral component, or a unicortical reduction plate to hold length and alignment while I pass the nail. I confirm a correct, slightly medial trochanteric start point on true AP and lateral before opening the cortex. **Reaming and nailing**: Reduce, ream gently with sharp reamers across the reduced fracture, insert the nail by hand, lock proximally, then SET ROTATION against the contralateral limb (lesser trochanter profile and cortical step-sign) before distal locking. I would statically lock this length-unstable pattern. **Post-op**: Protected weight-bearing advancing with callus, early ROM, VTE prophylaxis, and a low threshold to re-image if alignment is in doubt.

CLINICAL SCENARIOAdvanced

CLINICAL PROMPT

"A 12-year-old child has a femoral shaft fracture. A trainee suggests a standard adult piriformis-entry reamed nail. Why is this the wrong choice, and what would you do instead?"

PRACTICAL APPROACH

A piriformis-entry reamed nail is the wrong choice in a skeletally immature child principally because of the risk of avascular necrosis of the femoral head. **The anatomical reason**: The piriformis fossa start point lies close to the deep branch of the medial femoral circumflex artery. The MFCA gives the lateral epiphyseal (retinacular) vessels which are the DOMINANT blood supply to the capital femoral epiphysis. In a child, injuring this vessel at the entry point can cause AVN of the femoral head — a catastrophic, often joint-destroying complication. There is also the risk to the trochanteric apophysis and proximal femoral physis, which can cause growth disturbance and coxa valga/breva. **So the rule is**: NEVER use a piriformis entry in the skeletally immature or adolescent femur. **What I would do instead**: My implant choice is dictated by age, weight and fracture pattern: - For most school-age children with a length-stable shaft fracture, **flexible (elastic) intramedullary nails** are an excellent, physeal-sparing option with low complication rates. - For older or heavier adolescents, or length-unstable/comminuted patterns where flexible nails are inadequate, I would use a **lateral-entry RIGID (trochanteric) nail** designed to avoid the piriformis fossa, or **sub-muscular bridge plating**. - The exact choice depends on local protocol, but the unifying principle is to protect the femoral head blood supply and the proximal growth plate. **Other considerations**: Children's fractures have enormous remodelling potential and rapid union, so anatomic rigid fixation is not always necessary; length and rotation still matter and I would still set rotation against the other leg.

CLINICAL SCENARIOAdvanced

CLINICAL PROMPT

"A 35-year-old polytrauma patient has bilateral femoral shaft fractures, a flail chest with pulmonary contusions, and is hypotensive with a rising lactate. The trauma team asks whether you will nail both femurs tonight. What is your approach?"

PRACTICAL APPROACH

This is a clear scenario for DAMAGE CONTROL ORTHOPAEDICS, not early total care with bilateral reamed nailing tonight. **Assessment of physiology**: This patient is UNSTABLE — hypotensive with a rising lactate, and crucially has a significant chest injury (flail chest, pulmonary contusions). Bilateral femoral fractures already represent a major energy transfer with a higher systemic insult and mortality. Immediate bilateral reamed nailing would add a large surgical 'second hit': reaming raises intramedullary pressure and showers fat and marrow emboli into a lung that is already injured, risking ARDS and multi-organ dysfunction. **Damage control plan tonight**: I would apply temporary spanning EXTERNAL FIXATION to both femurs. This rapidly restores length and alignment, controls the fractures, reduces ongoing soft-tissue and embolic insult, allows pain control and mobilisation in bed, and buys time for resuscitation — all with a minimal physiological cost compared to reamed nailing. **Resuscitation and timing of definitive surgery**: In parallel the patient is resuscitated by the trauma team. The decision to proceed to definitive reamed nailing is driven by the RESPONSE to resuscitation — lactate clearance, normalising base deficit, restored perfusion, controlled coagulopathy and temperature — rather than a fixed clock. This is the 'safe definitive surgery / early appropriate care' concept. Once the patient is a responder and physiologically restored (often within a few days), I would convert the external fixators to definitive reamed antegrade nails. **Vigilance**: Throughout, I monitor closely for fat embolism syndrome and ARDS given the chest injury and bilateral femurs, and I ensure VTE prophylaxis. **Summary**: Damage control external fixation now; definitive reamed nailing once resuscitated and a demonstrated responder — protecting the injured lung from the reaming second hit.