Condylar Fractures of Femur (Distal Femur)
Distal femur fractures involve the supracondylar and intercondylar regions. They are notoriously unstable due to muscle pulls and often involve the knee joint surface.
1. Deforming Forces
- Gastrocnemius: Pulls the distal condylar fragment into Extension (recurvatum).
- Quadriceps/Hamstrings: Cause shortening.
2. Specific Types
- Supracondylar: Extra-articular.
- Intercondylar: Intra-articular (Y or T shaped).
- Hoffa Fracture: Coronal shear fracture of the posterior femoral condyle (usually lateral). Often missed on X-ray (needs CT).
3. Management
- Surgery (Standard):
- Lateral Locking Plate (LCP): Good for osteoporotic bone.
- Retrograde IM Nail: Through the knee joint. Good for extra-articular fractures.
- Rehab: Early ROM is critical to prevent knee stiffness (Quadriceps tie-down).
25 Practice MCQs
Q1. The distal fragment in supracondylar fracture is usually tilted:
Answer: B). Due to the pull of the Gastrocnemius muscle attachments.
Q2. Which artery is at risk due to the posterior tilt?
Answer: A). It is tethered close to the bone in the popliteal fossa.
Q3. Hoffa Fracture is:
Answer: A). Usually the lateral condyle. Unstable, requires screws.
Q4. Primary goal of treating intra-articular fractures is:
Answer: A). To prevent post-traumatic arthritis.
Q5. Retrograde nailing involves insertion through the:
Answer: A). Through the joint.
Q6. Which plate is commonly used for distal femur fractures?
Answer: A). Anatomically contoured.
Q7. Knee stiffness is a major complication due to:
Answer: A). The gliding mechanism is disrupted.
Q8. Fat fluid level (Lipohemarthrosis) on X-ray indicates:
Answer: A). Marrow fat leaks into the joint.
Q9. Non-operative treatment (Casting) is usually reserved for:
Answer: A). Due to high stiffness/malunion rates.
Q10. The "Muller AO Classification" type C refers to:
Answer: A). The most severe type.
Q11. Valgus deformity is a common malunion because:
Answer: A). Adductor magnus creates a strong moment.
Q12. CPM (Continuous Passive Motion) is used to:
Answer: A). Motion is lotion.
Q13. Lag screws are used to:
Answer: A). Interfragmentary compression.
Q14. Weight bearing is typically restricted for:
Answer: A). Joint surface needs protection.
Q15. Which nerve can be injured with lateral plating?
Answer: C). Though less common than in knee dislocations.
Q16. Hyperextension of the distal fragment is corrected by:
Answer: A). Essential during reduction.
Q17. Dual plating (Medial and Lateral) is used for:
Answer: A). Adds stability but strips more soft tissue.
Q18. Is total knee replacement an option for acute fractures?
Answer: A). "Distal Femoral Replacement" (Mega-prosthesis).
Q19. Quadricepsplasty (Thompson's/Judet's) is done for:
Answer: A). To regain flexion.
Q20. Non-union rate is higher in:
Answer: A). But modern locking plates have improved this.
Q21. A "Floating Knee" injury is:
Answer: A). The knee is disconnected from the rest of the skeleton.
Q22. Extensor lag is:
Answer: A). Common rehab challenge.
Q23. Which is crucial during surgery to prevent Valgus collapse?
Answer: A). If medial bone is missing, it collapses.
Q24. CT scan is recommended:
Answer: A). Shows Hoffa fragments.
Q25. Patellar mobilization in rehab prevents:
Answer: A). Critical part of PT.
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