What is the management approach for common failure of short Proximal Femoral Nails (PFN)?

Management of Short Proximal Femoral Nail (PFN) Failures

When a short PFN fails, the management approach depends critically on patient age, bone quality, and fracture characteristics: for elderly, frail patients with osteoporotic bone, proximal femoral replacement (PFR) is the preferred salvage treatment, while younger patients with better bone stock may be candidates for revision fixation with a longer cephalomedullary nail. 1

Understanding Common Failure Mechanisms

The primary causes of short PFN failure include:

• Technical errors during initial surgery - poor reduction, incorrect screw length selection, and inadequate distal locking are the most common intraoperative mistakes, occurring in approximately 19% of cases 2
• Biomechanical factors - subtrochanteric fractures, pathological fractures, and low American Society of Anesthesiologists (ASA) scores (indicating younger, more active patients) are independent risk factors for nail breakage 3
• Inadequate fracture reduction - even minor deviations in reduction will subsequently cause loosening and failure, particularly in 31A fractures 2

Risk Stratification for Failure

High-Risk Patients for Nail Breakage

• Younger patients (mean age 70 years) with low ASA scores - these patients place higher mechanical demands on the implant 3
• Subtrochanteric fracture patterns - these have the highest complication rates with short PFN 4, 3
• Pathological fractures - these should not be treated with PFN due to lack of bone healing potential 5

Time Course of Failure

• Mean time to nail fracture is 10 months (range 2.5-23 months), requiring close follow-up until bony union is confirmed 3

Salvage Treatment Algorithm

For Elderly, Osteoporotic Patients (Age >75-80 years)

Proximal femoral replacement is the first-line salvage treatment for this population 1:

• Immediate weight-bearing capability - critical for preventing complications in frail patients 1
• Technical straightforwardness - cemented stems should be used in all cases 1
• Functional outcomes - significant improvements in Harris Hip Score, FIM™, and Time Up and Go test at final follow-up 1
• Low one-year mortality rate compared to revision fixation 1

Critical pitfall to avoid: Dislocation is the most common complication (3/21 patients in one series), occurring primarily within the first six months after surgery 1

For Younger Patients with Better Bone Stock

Revision fixation with a longer cephalomedullary nail may be considered 3:

• Ensure complete fracture reduction before any revision attempt 2
• Use dynamic distal locking to allow compression at the fracture site and decrease risk of Z-effect, reverse Z-effect, and screw complications 6
• Consider PFNA2 (helical blade design) over conventional two-screw PFN for better bone compaction in compromised bone 6

Alternative Consideration for Pathological Fractures

Proximal femoral replacement should be strongly considered as primary treatment rather than attempting fixation, especially in patients with good prognosis from their underlying malignancy 3

Intraoperative Management Principles

When performing salvage surgery:

• Administer prophylactic antibiotics within one hour of skin incision 5, 7
• Implement active warming strategies to prevent hypothermia, particularly critical in elderly patients 5, 7
• Optimize fluid management - use cardiac output-guided fluid administration to reduce hospital stay and improve outcomes 7
• Ensure proper patient positioning to avoid pressure sores and neuropraxia 5

Postoperative Management

Thromboprophylaxis

• Administer fondaparinux or low molecular weight heparin for DVT prophylaxis 5, 7
• Time LMWH administration between 18:00-20:00 to minimize bleeding risk if neuraxial anesthesia was used 5

Pain Management

• Continue regular paracetamol throughout the perioperative period 5, 7
• Use opioids cautiously, especially in patients with renal dysfunction - reduce both dose and frequency (e.g., halved) 8
• Avoid codeine due to constipation, emesis, and association with postoperative cognitive dysfunction 5
• Use NSAIDs with extreme caution and contraindicate in renal dysfunction 5

Mobilization

• Implement early mobilization protocols immediately to reduce complications, particularly in elderly patients 5, 7

Follow-Up Surveillance

For patients treated with revision fixation rather than replacement:

• Close follow-up until bony union is achieved is mandatory, particularly for young patients with low ASA scores 3
• Monitor for signs of implant loosening at 6 weeks, 3 months, 6 months, and 12 months 4
• Assess for late complications including pseudoarthrosis and avascular necrosis of the femoral head 4