A tear to the medial collateral ligament in the knee can cause pain, swelling, and a lack of stability in the knee. Treatment is usually with ice, a knee brace, and physical therapy. Surgery may be necessary in rare cases.
All that slipping and sliding on tennis courts prevents injuries: A biomechanics expert explains how
Evidence has been available for decades to suggest that players have fewer knee problems if they play on clay courts rather than hard surfaces over their careers.