Differential Diagnosis of Inability to Flex Ankle
Single Most Likely Diagnosis
- Achilles Tendon Rupture: This is often the first consideration due to its direct impact on ankle flexion. A rupture would significantly impair the ability to flex the ankle due to the loss of continuity in the tendon that connects the calf muscles to the heel bone.
Other Likely Diagnoses
- Ankle Fracture: Fractures around the ankle joint can lead to pain and mechanical instability that may limit ankle movement, including flexion.
- Severe Ankle Sprain: A severe sprain, especially one involving the ligaments that support the ankle joint, can cause significant pain and swelling, limiting the range of motion.
- Peroneal Tendonitis or Tear: The peroneal tendons, which run along the outside of the ankle, can become inflamed or torn, affecting ankle stability and movement.
- Plantar Fasciitis: While primarily causing heel pain, severe cases of plantar fasciitis can lead to pain with ankle flexion, especially if the condition has led to a significant reduction in ankle mobility.
Do Not Miss Diagnoses
- Compartment Syndrome: A condition where increased pressure within a muscle compartment leads to inadequate blood supply to the tissues inside the compartment. It's a medical emergency that can result from severe injury, including those affecting the ankle.
- Neurological Conditions (e.g., Peripheral Neuropathy, Sciatica): Certain neurological conditions can affect the nerves controlling the muscles around the ankle, leading to weakness or paralysis that could be mistaken for a musculoskeletal issue.
- Infection (e.g., Osteomyelitis, Septic Arthritis): Infections in the bone or joint can cause severe pain and limitation of movement, including ankle flexion, and require prompt treatment to avoid serious complications.
Rare Diagnoses
- Tumors (Benign or Malignant): Tumors affecting the bones, muscles, or tendons around the ankle can cause pain and limited mobility.
- Rheumatological Conditions (e.g., Rheumatoid Arthritis, Lupus): These conditions can cause inflammation and damage to the joints, including the ankle, leading to limited movement.
- Charcot-Marie-Tooth Disease: A group of inherited disorders that affect the peripheral nerves, potentially leading to muscle weakness and atrophy, including in the muscles controlling ankle movement.