What is valgus instability?
Valgus instability is a condition related to the elbow joint, where there is excessive inward angulation of the medial joint line of the forearm concerning the upper arm. This condition typically arises from damage or laxity in the medial structures of the elbow, affecting the anterior and posterior bands of the ulnar collateral ligament (UCL). It is most commonly seen in athletes, such as baseball pitchers, who engage in repetitive throwing motions.
Symptoms of valgus instability
The primary symptom of valgus instability is medial elbow pain that worsens with activities involving throwing or forceful arm movements. Other common symptoms include:
- A sensation of the elbow "giving way" or instability during use
- Decreased throwing velocity or accuracy for athletes
- Swelling and tenderness around the elbow
- Possible ulnar nerve symptoms such as numbness or tingling in the hand if nerve compression occurs
Causes of valgus instability
Valgus instability is primarily caused by repeated valgus force and overuse of the elbow joint, leading to stretching or tearing of the ulnar collateral ligament. This is often seen in sports with frequent throwing motions. Other potential causes include:
- Acute trauma to the elbow, such as from a fall or direct blow
- Anatomical abnormalities that increase stress on the medial elbow
- Degenerative changes in the elbow joint from aging or previous injuries
- Less commonly, inflammatory diseases such as rheumatoid arthritis that weaken the ligament structure










