Question:medium
Fracture base of 5th metatarsal, below knee cast should be worn for
Fracture base of 5th metatarsal, below knee cast should be worn for
Show Hint
An avulsion fracture of cancellous bone with good blood supply heals in the standard fracture-union window, not weeks longer.
Updated On: Jun 22, 2026
- 6-8 weeks
- 2-3 weeks
- 16-20 weeks
- 3-5 weeks
Show Solution
The Correct Option is A
Solution and Explanation
Think about what determines cast time for any fracture: the bone type, blood supply and stability.
The fracture: The base of the fifth metatarsal is cancellous (spongy) bone with a generous blood supply - the proximal tuberosity avulsion typically unites well, unlike the watershed Jones fracture a little more distally.
Healing biology: Cancellous metaphyseal bone with good vascularity heals in roughly 6-8 weeks. A below-knee (short-leg) cast or walking boot held for this window protects the fracture through the soft-callus and hard-callus phases until union is achieved.
Matching the options:
$\bullet$ 2-3 weeks - only the inflammatory/early phase is complete; union not yet reached.
$\bullet$ 3-5 weeks - still premature; high re-displacement risk.
$\bullet$ 16-20 weeks - excessive; reserved for slow-healing or non-union situations, and would stiffen the foot.
$\bullet$ 6-8 weeks - matches the natural union time of this fracture.
Therefore the correct immobilisation duration is 6-8 weeks (option A).
The fracture: The base of the fifth metatarsal is cancellous (spongy) bone with a generous blood supply - the proximal tuberosity avulsion typically unites well, unlike the watershed Jones fracture a little more distally.
Healing biology: Cancellous metaphyseal bone with good vascularity heals in roughly 6-8 weeks. A below-knee (short-leg) cast or walking boot held for this window protects the fracture through the soft-callus and hard-callus phases until union is achieved.
Matching the options:
$\bullet$ 2-3 weeks - only the inflammatory/early phase is complete; union not yet reached.
$\bullet$ 3-5 weeks - still premature; high re-displacement risk.
$\bullet$ 16-20 weeks - excessive; reserved for slow-healing or non-union situations, and would stiffen the foot.
$\bullet$ 6-8 weeks - matches the natural union time of this fracture.
Therefore the correct immobilisation duration is 6-8 weeks (option A).
Was this answer helpful?
0
