Patellar tendon bearing cast is indicated in the following fracture:
**Core Concept**
Patellar tendon bearing (PTB) cast is a type of orthotic device used to manage fractures, particularly in the lower limb. It applies pressure to the patellar tendon, which is the tendon connecting the patella (kneecap) to the tibia (shinbone). This pressure helps to immobilize the knee joint and promote healing.
**Why the Correct Answer is Right**
PTB cast is indicated for fractures of the tibial plateau, which is the top part of the tibia. The cast applies pressure to the patellar tendon, which in turn exerts pressure on the tibial tuberosity, helping to stabilize the fracture. This is particularly useful for fractures that are comminuted or have a significant displacement. The PTB cast also helps to reduce pain and swelling in the knee joint.
**Why Each Wrong Option is Incorrect**
**Option A:** PTB cast is not typically used for fractures of the femoral condyles, as these fractures often require surgical intervention.
**Option B:** PTB cast is not indicated for fractures of the fibula, as these fractures do not require the same level of stabilization as tibial plateau fractures.
**Option C:** PTB cast is not typically used for fractures of the patella itself, as these fractures often require surgical intervention to ensure proper alignment and healing.
**Clinical Pearl / High-Yield Fact**
When using a PTB cast, it's essential to ensure that the cast is applied with the patellar tendon in a slightly flexed position to avoid putting too much pressure on the knee joint.
**Correct Answer: D. Tibial plateau fracture.**