Knee arthroscopy and meniscal tears: what keyhole surgery can and cannot fix

Introduction

Knee arthroscopy — keyhole surgery of the knee — is one of the most commonly performed orthopaedic procedures in Australia. For the right patient with the right diagnosis, it is highly effective. For others, particularly those with degenerative knee pain, it may offer little benefit. The difference matters enormously, and it begins with an accurate diagnosis.

Meniscal tears are among the most common reasons patients are referred for knee arthroscopy. But not all meniscal tears are alike — and the treatment that is right for one type of tear is not necessarily right for another.

What is knee arthroscopy?

Arthroscopy means looking inside a joint using a camera. In knee arthroscopy, the surgeon makes two or three small incisions — each about the size of a buttonhole — around the knee. A thin camera (the arthroscope) is inserted through one of these incisions, and fine instruments through the others. The interior of the joint is displayed in real time on a screen.

The procedure is performed under general or spinal anaesthesia and typically takes between 20 minutes and an hour. Most patients go home the same day. Knee arthroscopy is used to diagnose and treat a range of conditions: meniscal tears, cartilage damage, loose bodies within the joint, and in some cases ACL injuries.

The meniscus — what it does and why it matters

The meniscus is a C-shaped disc of fibrocartilage that sits between the thigh bone (femur) and the shin bone (tibia) on each side of the knee. The menisci act as shock absorbers, spreading load across the joint surface, and they contribute to stability and lubrication.

When the meniscus is torn, it can cause pain, swelling, clicking, and sometimes locking — where the knee becomes stuck and cannot fully straighten. Whether surgery is likely to help depends significantly on the type of tear.

Traumatic meniscal tears — when surgery helps

Traumatic meniscal tears typically occur in younger, active patients — often as a result of a twisting injury, a pivot while playing sport, or a fall. Many cause mechanical symptoms — catching, locking, or a sense that the knee is not moving smoothly. A displaced flap tear, in which a fragment of the meniscus folds into the joint and physically blocks movement, is a classic example. In these cases, arthroscopic surgery is usually appropriate.

Preserving the meniscus — where technically possible — is always the preferred goal. It is what protects the joint in the long term.

Meniscal repair — stitching the tear back together rather than removing the torn tissue — is the preferred approach when it is technically possible. Preserving the meniscus protects the joint from long-term arthritic change. Recovery after repair is longer than after debridement, but the benefit to the joint over a lifetime is significant.

Degenerative meniscal tears — a different problem

Degenerative meniscal tears are a fundamentally different entity. They occur in older patients — typically over 45 — and are a feature of the ageing knee rather than a discrete injury. The critical question is whether the symptoms are caused by the meniscal tear specifically, or whether they reflect underlying arthritis.

Multiple high-quality randomised controlled trials have compared arthroscopic partial meniscectomy with physiotherapy for degenerative meniscal tears, and the results are consistent: for most patients with degenerative tears, surgery offers no significant advantage over a well-structured exercise programme. This does not mean surgery is never appropriate — patients with true mechanical symptoms that have not responded to rehabilitation may benefit — but surgery is not the default first step.

Dr Mooney’s approach to degenerative tears

When a patient presents with a degenerative meniscal tear, Dr Mooney’s first step is to understand the full picture: the nature and severity of symptoms, any mechanical features, the degree of associated arthritis on imaging, and what the patient has already tried. An MRI showing a meniscal tear is not, by itself, an indication for surgery.

Meniscal root tears warrant particular attention. A root tear disrupts the attachment of the meniscus to the tibia, causing the entire meniscus to effectively extrude from the joint. This significantly increases load on the articular cartilage and can accelerate arthritis substantially. Root tears in appropriately selected patients may be repaired using a bone tunnel technique. Dr Mooney is experienced in this procedure.