Meniscal injury in runners

Meniscal injury in runners refers to painful damage to one of the knee menisci in someone who runs. The term is deliberately broad: it may correspond to a degenerative meniscal lesion, which develops gradually with repeated stresses and the ageing of the meniscal tissue, to a traumatic tear occurring after a sudden twisting movement of the knee, to a more specific lesion (longitudinal tear, bucket-handle tear, radial tear, meniscal root injury), or, more rarely, to a meniscal lesion associated with another knee injury, whether ligamentous or cartilaginous.

In runners, meniscal pain is most often promoted by a combination of repeated loading, knee flexion movements and rotational stresses.

Caution is needed, however: a meniscal tear visible on MRI can be completely asymptomatic, particularly in middle-aged runners. The aim is therefore not to “treat an MRI image”, but to determine whether the meniscus is really responsible for the symptoms the runner is experiencing.

Each knee has two menisci: the medial meniscus, located between the medial femoral condyle and the medial tibial plateau, and the lateral meniscus, located between the lateral femoral condyle and the lateral tibial plateau. They are crescent-shaped fibrocartilaginous structures positioned between the femur and the tibia.

The meniscus performs several functions essential to knee health. It contributes to shock absorption by distributing stresses between the femur and the tibia, and improves congruence between the joint surfaces by increasing their contact area. It also allows load transmission over a larger surface, thereby helping to protect the cartilage. It contributes to knee stability, particularly in certain positions of flexion and rotation, and contains mechanoreceptors involved in proprioception, that is, the perception of the knee’s position and movements.

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Blood supply: why some lesions heal better than others

The meniscus does not have a uniform blood supply. A distinction is classically made between a vascularised peripheral zone, sometimes called the “red zone”, an intermediate zone, and a poorly or non-vascularised central zone, called the “white zone”. This difference partly explains why peripheral lesions have greater healing potential than central lesions, which is particularly important when surgical repair is being considered. In runners, a small peripheral tear may therefore behave very differently from a complex lesion extending across a large part of the meniscus.

Biomechanics of the meniscus in runners

Running subjects the knee to thousands of loading cycles. With every stride, the meniscus helps to distribute stresses, absorb part of the load, maintain joint congruence, accompany flexion-extension movements and manage the stresses associated with tibial rotation.

It is under particular strain when loading is combined with deep knee flexion, tibial rotation, high compression, a sudden change of direction or a dynamic landing — which explains why going down stairs, downhill running, running on steep uphill slopes, technical trail running, deep squats, prolonged crouching and pivoting movements are particularly symptomatic situations.

In runners, two quite distinct profiles are seen. On the one hand, the traumatic lesion, which is rarer, occurring after a sudden change of direction, a foot planted on the ground while the body rotates, or a sports injury, sometimes associated with an anterior cruciate ligament injury. On the other hand, the degenerative lesion, much more common in regular runners, which develops gradually, without any identifiable traumatic event, and is often associated with early osteoarthritis.

Degenerative meniscal lesions are also common in people with no symptoms at all, particularly after the age of 40-50: a tear visible on MRI therefore does not automatically mean that it is causing the runner’s pain, nor that surgery is needed.

Two main mechanisms should be distinguished. The traumatic lesion typically occurs after a sudden change of direction, a foot planted on the ground while the body rotates, a poorly controlled landing, a twisting movement in flexion or a sports injury: the runner then feels sudden pain, sometimes accompanied by swelling of the knee, and an anterior cruciate ligament injury may be associated.

The degenerative lesion, on the other hand, develops more gradually. Over time, the meniscus may show disorganisation of its fibres, horizontal or complex tears, a progressive loss of its mechanical properties, partial extrusion, or an association with early osteoarthritis. In these patients, it is often impossible to identify a specific traumatic event: running is not necessarily the cause of the lesion; it may simply reveal a meniscal structure that has become symptomatic in a context of high stresses.

Training-related factors

A sudden increase in mileage, returning too quickly after a break, adding more sessions, increasing volume and intensity at the same time, a large increase in elevation gain, a sudden change of terrain, recently taking up trail running or repeated long descents can promote the onset or persistence of symptoms.

Biomechanical factors

A lack of strength in the quadriceps or hamstrings, weakness of the gluteal muscles, impaired control of the lower limb, poor tolerance of deep flexion, or limited ankle or hip mobility that may alter movement strategy are frequently found. There is, however, no “single biomechanical flaw” responsible for meniscal injuries.

Knee-related factors

Early or established osteoarthritis, a previous meniscal injury, a previous meniscectomy, ligamentous instability, a significant axial deformity or a recent injury are also contributing factors.

The presentation depends heavily on the type of lesion. The classic symptom is pain localised to the joint line — medial when the medial meniscus is affected, lateral when the lateral meniscus is affected — which the patient can sometimes point to precisely with a finger.

Pain during running may appear during exercise, after several kilometres, at the end of a session, a few hours after training or sometimes only the next day. Some lesions are also particularly symptomatic in flexion: when squatting, crouching, on stairs or when sitting for a long time with the knee bent.

Swelling (joint effusion) may appear after exercise; rapid, marked swelling after an injury should prompt a search for an associated lesion, particularly a ligament injury. The patient may also describe catching or locking: a catching sensation, a click, a feeling that the knee “gets stuck”, or difficulty straightening the knee fully. A simple painless click must be distinguished from true mechanical locking, which is a more important warning sign.

Clinical examination

The examination should look both for a meniscal origin and for the many other possible causes of knee pain. Inspection looks for effusion, quadriceps wasting, an abnormal fixed position, axial deformity or localised swelling. Palpation of the joint line (medial and lateral), the patellar tendon, the patellar facets, the femorotibial joint, the pes anserinus and the iliotibial band helps pinpoint the source of the pain. Assessment of mobility (full extension, flexion, pain at maximum flexion, any locking) is essential: a loss of extension is particularly important to identify.

Several meniscal tests can complement the examination: the McMurray test, the Apley test, the Thessaly test, joint line palpation, and checking for a clunk or catching. However, no single test can confirm or rule out a meniscal lesion with certainty: interpretation must take into account the injury mechanism, age, symptoms, the overall examination and any imaging.

In degenerative meniscal injury, surgery is generally not the first-line treatment. Partial meniscectomy involves removing the unstable or damaged part of the meniscus: it can quickly reduce certain mechanical symptoms, but it also reduces the amount of meniscal tissue available to distribute loads. The ESSKA guidelines and the recent international consensus therefore recommend non-operative management first, particularly rehabilitation. Meniscectomy may be considered in certain patients with persistent symptoms despite properly conducted conservative management.

A specialist opinion is particularly relevant in the event of true locking of the knee, persistent inability to achieve full extension, a bucket-handle or meniscal root lesion, acute trauma with a significant meniscal lesion, recurrent effusions, instability, persistent pain despite several months of properly conducted treatment, a meniscal lesion associated with a ligament injury, or a suspected osteochondral lesion. Acute traumatic lesions are a different situation from degenerative lesions and require individualised assessment.

When surgery is necessary, the modern aim is to preserve the meniscus as far as possible. Meniscal repair seeks to preserve the tissue by suturing the lesion; it may be preferred when the lesion is repairable, the location is favourable, the tissue is sufficiently viable and the patient’s circumstances are compatible with healing. Partial meniscectomy involves removing only the unstable tissue when repair is not possible or appropriate. This meniscal preservation is particularly important in young athletes, because of the long-term consequences of a significant loss of meniscal tissue — notably an increased risk of degenerative changes.

The time needed to return to running depends heavily on the procedure performed. After a partial meniscectomy, return to sport can be relatively quick, often in the order of several weeks when recovery goes well. After a meniscal repair, recovery is generally much longer, because the meniscus must be given time to heal. The recent ESSKA-AOSSM-AASPT consensus suggests, as a guide, around 4 to 12 weeks after partial meniscectomy and 6 to 9 months after meniscal repair, with these timeframes to be adapted to the type of lesion, the surgical procedure, any associated lesions and functional criteria.

Outside the surgical setting, there is no single timeframe that applies to all meniscal injuries: recovery depends on the type of lesion, whether it is traumatic or degenerative, the condition of the cartilage, the presence of associated osteoarthritis, muscle strength, activity level and the ability to adapt the training load.

The return to running should therefore be guided by functional criteria rather than by an arbitrary timeframe: pain, absence of effusion, mobility, strength, neuromuscular control, the ability to absorb impact and tolerance of a gradual increase in training volume. The prognosis is generally favourable for properly managed symptomatic degenerative meniscal injuries: a meniscal injury does not necessarily mean giving up running for good.

There is no programme that can prevent all meniscal injuries, but certain measures can reduce the risk of overload. A gradual progression in training, avoiding sudden increases in mileage, remains essential. It is useful to vary the type of stress — endurance, recovery, strengthening and speed work — rather than piling up similar sessions.

Maintaining good muscle capacity in the quadriceps, hamstrings, glutes and calves, together with single-leg work to control the lower limb effectively when weight-bearing, contributes to prevention. When returning to trail running, it is better to gradually increase distance, elevation gain, elevation loss and technical difficulty, without increasing all of these parameters at the same time.