Rugby

For Patients

The Principle

If something can be pushed from any direction, it has to be strong in every direction.

A knee is not. It is built to bend one way and to resist the others with ligaments.

Adding another person's weight and speed to the force is what makes contact sport different.

At the Knee

Rugby has all the turning and landing injuries of football, with contact added. 3.15.1 covers those.

The characteristic rugby mechanism is a tackle to the side of a planted leg, which bends the knee in a direction it does not bend.

A blow to the front of a bent knee, as in a tackle or a fall onto it, loads the ligament at the back of the joint.

Scrummaging and rucking load the knee while the foot is fixed and the body is being pushed, which is the same problem held for longer.

Clinical Relevance

The direction of the tackle is useful information, because it predicts which structures were loaded.

A knee injured by a blow to the outside and one injured by a twist are different problems with different recoveries.

Several structures are often injured together in contact sport, which lengthens rehabilitation. 6.4 covers associated injuries.

No injury rates are given on this page, because no source was available to check them against.

For Medical Students

The Principle

Contact sport adds an externally applied force of a magnitude and direction the athlete does not control.

That removes the protective value of anticipation, which is the mechanism most prevention training relies on. 3.14.6 covers anticipation.

So contact injuries are less preventable by training and more influenced by law and by technique.

At the Knee

Lateral blow to a planted limb produces valgus with or without rotation, injuring the medial collateral complex and, at higher force, the cruciate. 3.9.10 covers the combination.

A blow to the anterior tibia in a flexed knee, from a tackle or a fall, is the classical posterior cruciate mechanism. 3.8 covers the ligament.

A medially directed blow produces varus and loads the lateral structures and the posterolateral corner. 3.10.6 covers the corner.

Non contact mechanisms persist and account for a substantial share, particularly in backs. 3.7.14 covers them.

Multiligament injury is more common in contact sport than in non contact sport, which changes the assessment. 6.4 covers associated injuries.

What Changes It

Position, since forwards and backs have different exposures.

Laws of the game, particularly those governing tackle height and the ruck.

Playing surface and footwear traction.

Fatigue and match time, which affect non contact mechanisms more than contact ones.

Previous injury and the quality of rehabilitation.

Clinical Relevance

Take the direction of force in the history, since it predicts the structures involved.

Examine for multiligament injury rather than assuming a single structure. 6.4 covers them.

Assess the posterolateral corner when the mechanism was a varus or hyperextension force. 3.10.6 covers it.

Describe mechanism rather than quoting rates, as this page does, because no source was available.

MRCS Level

The Principle

In contact sport the clinically important question shifts from which ligament to how many, because the energy available exceeds a single structure's capacity.

A multiligament knee is a different clinical entity from a single ligament knee, with different urgency and different consequences.

That reframing is the main thing rugby adds to the chapter.

At the Knee

Valgus with external rotation loads the medial collateral and posteromedial corner, and then the anterior cruciate. 3.9.10 covers the sequence.

Varus with internal rotation or hyperextension loads the lateral and posterolateral structures, and the common peroneal nerve is at risk. 3.10.6 covers the corner.

Hyperextension loads the posterior cruciate and the posterior capsule, and at high energy threatens the popliteal vessels.

Knee dislocation in sport is rare and is a limb threatening injury whose vascular assessment cannot wait. Section 6 covers the condition.

Anterolateral structures are commonly involved in the rotational component and are underdiagnosed. 3.11.6 covers the Segond lesion.

What Changes It

Energy of the collision, which is a function of player mass and closing speed.

Direction of the applied force, which determines the structures sequentially loaded.

Foot fixation at the moment of contact, which determines whether the force is absorbed or transmitted.

Law changes and their enforcement, which are the sport's main population level lever.

Protective equipment, which has limited evidence at the knee.

How It Is Measured

Video analysis of match injuries, which is the main evidence for contact mechanisms. 3.7.14 covers the approach.

Instrumented mouthguards and wearables, which measure collision load and were developed for the head rather than the knee. 3.16.8 covers wearables.

Cadaveric and robotic sectioning studies, which establish which structures resist which direction. 3.16.2 covers robotic testing.

Injury surveillance in professional competitions, which gives rates this page does not quote, because no source was retrieved.

There is no measurement of knee load during a tackle, so the mechanisms are inferred from video and from sectioning studies.

Clinical Relevance

Assess for multiligament injury and for vascular and nerve compromise after a high energy mechanism, since those cannot wait.

Record the direction of force, because it maps onto the structures loaded.

Look for anterolateral involvement in rotational mechanisms, which is underdiagnosed. 3.11.6 covers it.

State that contact mechanisms are inferred from video and sectioning rather than measured.

Weigh the player's age, physiology, comorbidities, knee demand, psychological state and their own ideas, concerns and expectations, since return to contact is a decision about accepting a repeat exposure.