Intertrochanteric Fracture: Proximal Femoral Nailing - Surgical Reference

1. Classification

AO/OTA 31-A System (most widely used)

• Boyd & Griffin (older): Type 1 = along intertrochanteric line; Type 2 = comminuted; Type 3 = subtrochanteric extension; Type 4 = comminuted with 2 planes
• Evans-Jensen: Widely used, emphasizes reducibility and posteromedial cortex integrity

Lateral Wall Assessment

2. Implant Selection: Why PFN Over SHS?

Biomechanical Rationale for Intramedullary Fixation

• Shortened bending lever arm (nail lies within the femoral canal, vs. SHS plate on lateral cortex)
• Better load transfer to medial calcar
• Less femoral neck shortening and medialization
• Smaller incision, less blood loss

Evidence-Based Indications for Cephalomedullary Nail

• AO/OTA A2 (unstable, comminuted) - preferred
• AO/OTA A3 (reverse obliquity, transverse) - mandatory; SHS contraindicated as fracture line opposes sliding and promotes failure
• Lateral wall insufficiency (< 21 mm)
• Subtrochanteric extension
• High-energy fractures in young patients
• Any fracture where posteromedial calcar support is absent

From Rockwood & Green (2025): "The sliding hip screw may still be used for stable A1 fractures and the cephalomedullary nail is recommended for unstable A2 and A3 fractures." Most studies now report improved functional outcomes with cephalomedullary nails, largely due to reduced collapse and femoral medialization.

Available Implants

• Gamma Nail (Stryker) - original standard; 6° valgus angle
• PFNA / PFN-A (Synthes) - helical blade design; better rotational control
• TFN-ADVANCED (TFNA) (DePuy Synthes)
• InterTAN (Smith & Nephew) - dual integrated proximal screws for linear intraoperative compression; theoretically better rotational stability
• Trigen / Targon - demonstrated equivalence to SHS in adequate RCTs

3. Preoperative Planning

Checklist

Timing

4. Surgical Technique: PFN (Cephalomedullary Nailing)

Step 1 - Patient Positioning

1. Supine on fracture table with perineal post (pad generously to avoid pudendal/perineal nerve injury).
2. Contralateral limb in well-leg holder (lithotomy) or scissored position (hip extended relative to injured side). Scissor position preferred if contralateral hip motion is limited.
3. Injured limb: apply traction boot securely. Apply longitudinal traction + internal rotation for reduction. Correct typical deformity - varus and posterior sag of the proximal fragment.
4. 20-30° of hip flexion on injured side (Campbell's recommendation) to align nail entry with femoral canal.
5. Adduct torso; ipsilateral arm secured over chest to allow unobstructed fluoroscopy.
6. Image intensifier: positioned to obtain perfect AP (lesser trochanter visible as bony landmark for rotation) and lateral views. Save a true AP image of the contralateral knee as rotation reference before prep.

Step 2 - Fracture Reduction

• Under fluoroscopy: AP view checks varus/valgus; lateral checks anterior/posterior sag.
• Acceptable reduction: slight valgus preferred over varus; neutral or 10° valgus on AP; neutral on lateral.
• Anatomical reduction is NOT required and is not always achievable - controlled collapse is acceptable and expected.
• If closed reduction fails: a Schanz pin inserted percutaneously into the proximal fragment as a joystick can correct the typical flexion-abduction-external rotation deformity.
• The proximal fragment "deforming forces": iliopsoas pulls it into flexion and external rotation; abductors cause abduction.

Step 3 - Nail Entry Point (Critical Step)

This is one of the most common sources of malalignment.

• Incision: 3 cm skin incision, approximately 5 cm proximal to the tip of the greater trochanter
• Incise fascia lata; split muscle to expose trochanteric tip
• Insert guide pin under fluoroscopy; confirm AP and lateral position before opening the canal

• Too lateral entry → varus malalignment of nail + fracture
• Too medial entry → valgus malalignment, possible iatrogenic femoral neck fracture
• Too anterior on lateral → apex anterior deformity

Step 4 - Canal Opening and Reaming

• Open proximal femur with appropriately sized solid channel reamer (trochanteric reamer)
• Depending on nail design and diameter, sequential reaming of the femoral canal may be required
• Ream to 1-1.5 mm beyond desired nail diameter for unreamed technique; or full reaming to nail diameter + 0.5 mm
• Avoid eccentric reaming ("trajectory control") - maintain guide wire centrally

Step 5 - Nail Insertion

• Select nail with appropriate neck-shaft angle (usually 125° or 130°) and appropriate valgus angle
• Insert nail by hand where possible; mallet with light taps if resistance encountered
• Do NOT force - if significant resistance, check fluoroscopy for malalignment or inadequate reaming
• Advance until the proximal end is at or just below the tip of the greater trochanter (flush or 2-3 mm recessed)
• Check AP and lateral views for nail position and maintenance of fracture reduction

Step 6 - Proximal Locking (Cephalic Screw/Blade Insertion)

1. Insert guidewire through the jig hole into the femoral head
2. Target position:
   • AP view: central or slightly inferior in the femoral head (below the center of the femoral head, near the calcar)
   • Lateral view: central in the femoral neck and head (not anterior or posterior)
3. Tip-Apex Distance (TAD) < 25 mm - mandatory. TAD = sum of distances from screw tip to femoral head apex on AP + lateral views. Risk of cut-out increases exponentially above 25 mm.

From Campbell's (2026): "As the tip-apex distance increases above 25 mm, the risk of failure increases exponentially."

1. Measure guidewire length; drill over wire; tap if required (dense cortical bone)
2. Insert lag screw/blade to appropriate depth (5 mm from subchondral bone = tip 5 mm from joint line on both AP and lateral)
3. Do NOT rotate the femoral head during screw insertion - prevent by: fingertip on anterior femoral neck, tap channel before insertion, or temporary antirotation wire
4. Compress the fracture by removing traction before final tightening (intraoperative compression improves bone-to-bone contact)
5. Set screw (end cap) insertion to control sliding versus static fixation depending on implant design

• Single screw (Gamma, standard PFNA): simpler, adequate for most
• Dual screws / blade (PFNA-II, InterTAN): improved rotational stability, especially for A3 and basicervical patterns
• Helical blade (PFNA): compacts rather than cuts bone; better hold in osteoporotic bone

Step 7 - Distal Locking

• For short nails in stable A1 fractures: unlocked can give comparable results; however, all short nails should be locked per current guidelines
• Dynamic locking: allows longitudinal compression during weight bearing - preferred for transverse patterns (A3)
• Static locking: rigid length-stable construct - preferred for comminuted unstable fractures (most A2)
• For long nails: distal locking is required for all unstable fractures
• Use freehand technique for distal locking (radiolucent drill guide or freehand targeting under fluoroscopy)

Step 8 - Final Fluoroscopic Checks

• AP hip: nail depth, cephalic screw position (central-inferior on AP), TAD
• Lateral hip: cephalic screw central in femoral neck
• AP full femur (if long nail): nail tip not abutting anterior cortex distally
• Rotation: compare lesser trochanter profile to pre-op reference image

Step 9 - Wound Closure

• Irrigate; close fascia lata; subcutaneous; skin
• Drain: not routinely required

5. Intraoperative Pitfalls and Solutions

6. Postoperative Management

• Weight bearing: Full weight bearing as tolerated from POD 1 (if fixation is stable and patient allows) - early mobilization reduces medical complications
• DVT prophylaxis: LMWH commencing 12 hours post wound closure; continue for minimum 28 days
• Physiotherapy: Commence day 1; sit out of bed POD 1; walking frame/zimmer frame
• Radiographs: AP pelvis and lateral hip at 6 weeks, 3 months, 6 months, and 1 year

7. Complications and Management

Management of Cut-Out

• Minor cut-out with acceptable reduction: allow fracture to heal conservatively
• Severe cut-out with hardware failure: revision fixation if adequate residual femoral head bone stock; cemented hemiarthroplasty or THA if bone stock inadequate
• SHS with varus collapse/plate detachment: convert to cephalomedullary nail, longer plate, or arthroplasty

8. Special Situations

Reverse Obliquity (A3) Fractures

• SHS is contraindicated - the fracture geometry causes the distal fragment to migrate medially when force is applied, directly opposing the sliding mechanism
• Long cephalomedullary nail is the implant of choice
• Standard nail (Gamma) or InterTAN/TFNA preferred; long nail if subtrochanteric extension

Basicervical Femoral Neck Fractures

• Behaves more like an IT fracture than a neck fracture
• High failure rate with SHS (6/11 in one series with cut-out)
• Cephalomedullary nail preferred; add derotational screw

Young High-Energy Fractures

• Anatomical reduction is more important
• Fixation should be rigid; bone stock allows more aggressive fixation
• Consider long nail with static locking

Osteoporotic Bone

• Helical blade (PFNA) compacts bone rather than removing it - superior hold
• Cement augmentation of cephalic screw is an option in extreme osteoporosis (some systems allow)
• Avoid over-reaming; preserve endosteal bone

Subtrochanteric Extension

• Use long cephalomedullary nail
• Trajectory control is paramount: precise entry point, channel reaming to avoid eccentric reaming
• Lock with cephalomedullary screws; may use Gamma, TFNA, or InterTAN for better curvature match

9. Key Numbers to Remember

10. Implant Comparison Summary

From Rockwood & Green (2025): "Most studies have reported improved functional outcomes with cephalomedullary nails. This is probably due to the reduced collapse and femoral medialization as the fracture heals in a more anatomical position."

• Campbell's Operative Orthopaedics 15th Ed 2026, Chapter 60, pp. 3448-3476
• Rockwood and Green's Fractures in Adults 10th Ed 2025, Chapter 54, pp. 2700-2730