Through two or more small incisions, a camera is put into the knee. This allows visualisation of the structures inside the knee. These include the meniscus cartilage, anterior cruciate ligament and the joint surface cartilage. Using specially designed instruments, abnormalities in the cartilage can be repaired or trimmed to help relieve symptoms. Conditions treated are:
Meniscal tears – These can be repaired if the tear is picked up early and is in a part of the meniscus which has a good blood supply, thus allowing healing. If the tear cannot be repaired, it is debrided (tidied up) to stop the torn section from getting in the way of smooth joint motion. This can stop the knee from ‘giving way’ (where the knee buckles suddenly), ‘locking’ (when the knee gets stuck in a specific position) or reduce pain associated with the tear.
Osteoarthritis – Sometimes, patients get mechanical symptoms in their knee in association with osteoarthritis. These can be ‘giving way’ and ‘locking’ due to the arthritis itself or sometimes there is an associated meniscal tear. Occasionally, a ‘loose body’ can form within a degenerate joint. It is not clearly understood how this happens, but mechanical symptoms can result which are also relieved by arthroscopy.
Ligament reconstruction – Cruciate ligament (ACL) reconstruction is usually done arthroscopically. Two hamstring tendons are first removed from the inner aspect of the knee and thigh to use as graft to form the new ligament.
Osteochondral defects in young people can be treated with ‘microfracture’. Here, the bone exposed because of joint cartilage damage is drilled in a controlled way to encourage new cartilage formation to give pain relief and hopefully delay the onset of arthritis.
Medial plica syndrome - a medial plica is a fold of tissue within the knee which can be symptomatic in some patients. It can mimic a meniscal tear. An inflamed plica found at arthroscopy can be cut out to relieve associated symptoms.
Keyhole surgery is a commonplace procedure. It is almost always done as a day case procedure. ACL reconstruction is also usually done as a day case procedure, though occasionally, overnight stay may be needed.