Meniscal or cartilage tears affect cartilage structures which can be found between the femoral and tibial cartilage on the inside (medial) and outside (lateral) of the joint. They have an important function in load transmission, thereby protecting the joint cartilage from wear. They also help with stability, shock absorption and nutrition. A meniscus can tear at any age, usually with a twisting or deep knee bending injury. At older ages a minor twist can cause the tear. The majority of the meniscus lacks blood supply so the tear is unlikely to heal except in the first 2 decades of life. Meniscal tears can be acutely painful and associated with initial swelling, giving way sensations, locking and clicking. Symptoms tend to improve but if there are persistent symptoms beyond 3 months further natural improvement is unlikely. A meniscal tear is not seen on x-rays and an MRI scan is the best way to diagnose it. An arthroscopy (keyhole surgery) is an option for treatment.