Femoral Inter-trochanteric Fracture

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AO Classification

• 3 (femur) 1 (proximal) A1 = stable; A2 = unstable; A3 = reverse oblique, transtrochanteric

• Acute management

• No evidence for traction in Cochrane reviews 2011 by Martyn Parker et al. – does not improve pain relief, ease of fracture reduction, or quality of fracture reduction

• I am aware that the Intramedullary Device is theoretically biomechanically more stable due to:
• 1. shorter moment arm and thus more suited for unstable A3 fractures.

• 2. Higher torsional and bending rigidity as Second Moment Area, Polar Moment Area are proportionate to power of 4 of radius compared to power of 3 of the thickness of plate
• However, it's not conclusive in literature whether this impacts clinical outcomes
• For example, Martyn Parker's 2018 Meta-analysis in Injury Journal found comparable fracture healing and complication rates for A3 fractures (reverse oblique and transtroch) between DHS and Intramedullary Nail!
Art_Parker M- Nail or plate fixation for A3 trochanteric hip fractures.pdf659.7KB
• In my practice, for unstable fractures as described by JAAOS ten tips paper Haidukewych - Reverse oblique, transtroch, subtroch extension, loss of lateral buttress, loss of medial calcar → IM device
• But I consider the risk of the unique complication of cut-in – whereby the stiffness of the implant results in cutting through of the osteoporotic bone into the head and acetabulum
• So in DHS, I aim for Tip Apex Distance (TAD) < 25mm based on Baumgartner's 1995 paper, but for Nail, I aim for TAD 20mm-30mm
10 tips.pdf1508.8KB

• Draw and explain failure by shear stresses. Shear stresses > stiffness of implant
• Loss of lateral buttress support, proximal fragments continue to slide unstopped.

• Study of 198 fractures, found to have 19 failures. 16 were due to cut-out. Average Tip apex Distance was 24mm for healed fractures, compared to 38mm for failures. None of the screws with TAD < 25mm cut out.

• Left side has increased risk of malreduction when tightening the DHS screw
• Left side rotational torque causes an anterior spike
• Solution - insert holding wire OR reverse turn towards the end

• McLoughlin et al. 2000 in JOT found no biomechanical difference in their biomechanical study.

• I choose a short barrel if the screw is < 85mm in length to allow sufficient collapse and sliding of the fracture site
• Thread length is default 22mm
• Aim is to allow sliding distance of at least 25mm
• The shortest length the standard barrel (38mm) can accommodate is an 85mm screw (25 + 22 + 38 = 85mm)
• If shorter, then we should use the short barrel which is 25mm
• Therefore, the standard barrel can accommodate a screw length of 25 + 22 + 38 = 85mm. If the screw is shorter, the sliding length will be less than 25mm.
• Threads should capture as much distal bone as possible but should not cross the fracture line to allow compression → Choose long threads unless it crosses fracture line
• Longer barrel offers a longer lever arm to resist bending and thus less friction to sliding → choose long unless barrel crosses fracture line and prevents sliding

• By looking at the native neck-shaft angle

• Avoid VARUS angulation because this will:
• 1. Increase moment arm on the fixation
• 2. Result in DHS screw being higher in the head → higher risk of cut-out
• 3. When resolving forces, lead to more bending force than compression forces

"I will aim for fracture reduction with positive medial cortical support and valgus alignment"

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4436685/

• Some authors advocate using long nails to prevent stress risers. However, long nails lead to longer surgery times and more blood loss.
• A local study by Andrew Hong et al. found no difference in clinical and functional outcomes between patients treated with long and short nails. However, they noted longer operation duration and increased estimated blood loss.

• In my practice, my decision is based on the extent of subtrochanteric extension.
• Various thresholds exist in literature, with some suggesting as little as 1cm.
• Shannon et al. 2018 Bovill Award Paper in JOT showed similar outcomes for short nails vs. long nails with no difference in implant cut-out, surgical site infection, or fractures when subtrochanteric extension is defined as >3cm from the tip of the lesser trochanter.

• In in-vitro biomechanical studies, cement increases load to failure by 12-37%.
• No consensus exists for routine cement augmentation.
• Kammerlander et al. 2018 in Injury, Multicenter RCT. No increased complications
• I will consider cement augmentation for patients with significant comorbidities that affect bone density, e.g., renal osteodystrophy, severe osteoporosis.

• Management of this complication is based on patient and injury factors.
• P - still mobile, active → need to address it
• I - depends if united or not
• Options = Replace or Re-fixation
• My options are removal and refixation with an angle blade plate
• OR replacement with a total hip implant with length bypassing the most distal screw by at least 2 cortical widths
• How will you do a replacement?
• This will be a complex primary procedure - pre, intra, post
• Pre-op - template, CT scans, check length of implant required; have long cemented stems and calcar replacement stems on standby
• Intraop - EEERR mnemonic
• Exposure - posterior extensile approach
• Explant - explant the implant
• Examine and Reconstruct - examine and reconstruct the calcar if required
• Replace - replace with long stem cemented implant
• Post-op Rehab - full weight bearing as tolerated

• Will not be using a primary stem but a revision stem with or without calcar replacement
• Will need to have distal purchase
• This will be either a long cemented or long cementless stem