**Core Concept**
Charcot's joints, also known as neuropathic arthropathy, are a type of joint degeneration that occurs due to sensory neuropathy. In diabetes mellitus, peripheral neuropathy leads to loss of proprioception and sensation in the feet, predisposing individuals to Charcot's joints.

**Why the Correct Answer is Right**
Charcot's joints are most commonly seen in the weight-bearing joints of the foot, particularly the **first metatarsophalangeal joint** and the **midtarsal joints**. This is because these joints bear the majority of the body's weight and are subjected to repetitive stress, leading to chronic inflammation and degeneration. The loss of sensation in the feet makes patients unaware of the gradual destruction of these joints, leading to a characteristic "rocker bottom" deformity.

**Why Each Wrong Option is Incorrect**
**Option A:** The knee joint is not typically involved in Charcot's joints due to its relatively lower stress and mobility compared to the weight-bearing joints of the foot.
**Option B:** The ankle joint is involved in Charcot's joints, but it is not the most common location. The midtarsal joints are more frequently affected.
**Option C:** The hip joint is not typically involved in Charcot's joints, as it is a less weight-bearing joint compared to the foot.

**Clinical Pearl / High-Yield Fact**
Charcot's joints are a classic example of a "silent" neuropathic disorder, where patients are unaware of the gradual destruction of their joints due to sensory neuropathy. Early recognition and treatment are essential to prevent further joint damage and deformity.

**Correct Answer:** C.