A Study of Common Knee Injuries in Rugby.
by Patrick Traylor
Rugby union, since turning professional in 1995, has required
players to adapt to the demands of increased physical and
mental robustness as well as show the strength and the pace
expected of a full time athletes, in order to stay injury
free. There have been studies conducted since then that show
that the higher the standard of rugby, the higher the chances
of an injury occurring. There are many possible reasons for
this which include longer playing seasons, higher levels of
competitiveness, increased intensity in training techniques
and the fact that it is a full time job so they spend most
of their time trying to develop into better players, physically
and mentally. This article is hopefully going to explain when
(during a match), where (anatomically) and how (event) injuries
occur. It will also look specifically at knee injuries.
rugby is a full contact sport, it produces a variety of different
injuries over the entire body. There is not an exact prescribed
way of tackling or taking the ball into contact, so people play
in different ways and these alternative interpretations of the rules
may contribute to a large number of injuries. Looking at studies
done on injuries in rugby, it can be seen they all have similar
methods of categorizing the type of injury and its severity. They
pinpoint where on the body the injury is and then grade its severity
by how many days are lost in training or play.
Common Injuries in Rugby
When looking at rugby injuries there are some areas of the body
that are more prone to injuries than others. The most common area
of injury is the thigh; most of these injuries are either hamstring
strains or ”dead legs”. Hamstring injuries are common
due to the ‘stop-start’ nature of the game: a sudden
burst of speed can cause a strain in a cold hamstring. Head and
neck injuries occur regularly in rugby, usually in forwards, due
to scrums collapsing and with close contact in and around rucks.
Knee injuries however, along with head and neck injuries, are probably
among the most serious injuries in rugby. They may not be the most
common, but they can be very severe. On average 10 knee injuries
per club per season results in a mean 353 days of absence due to
injury. (Dallalana et al. 2007)
The two most commonly occuring and written about injuries in rugby
are damage to the ACL (Anterior Cruciate Ligaments) and MCL (Medial
Collateral Ligament). A complete rupture of the ACL causes an average
of 254 days out and accounted for 2 of 3 retirements due to knee
injuries (Dallalana et al. 2007). A MCL tear grade 1, which is the
most common and least severe, can cause a minimum of 15 days out.
(Dallalana et al.2007)
Studies aim to find out which areas of the game cause the most
injuries in order to develop rules to prevent these happening. It
has been proven that contact between players accounts for most of
the injuries during a game. Tackling, rucks and mauls cause the
least amount of injuries, probably due to the fact that players
are in control when tackling. The occurrence of injury has been
shown to be higher when being tackled compared to making the tackle.
(Dallalana et al. 2007) This could be because players are not sure
where and when the tackler will be, which limits the ball carrier's
ability to avoid injury. Unlike rucks and mauls where changes in
the rules can prevent injuries, it would be harder to make the tackle
safer without changing the nature of the game. Coaches could be
encouraged to teach correct falling techniques as it has been shown
that a lot of injuries are due to the way players fall.
Effect of Match Duration on Injury
There is no clear-cut conclusion about what effect time in the
match has in relation to occurrence of injuries. One idea is that
injuries are fewest in the first quarter of the match. This could
be due to players being fully warmed up and fresh at the beginning.
Considering fatigue, a theory could be proposed that there would
be more injuries in the last quarter due to fatigue. Levels of fitness
would also have to be considered, and these would be associated
with the stage in the season. For example you would expect players
to be fittest at the beginning of the season due to the intense
pre-season fitness regimes. The failure of recent suudies to show
higher injury rates as the match progresses could be due to the
introduction of substitutions of players in 1997, giving coaches
an opportunity to substitute fatigued players.
For a knee to be stable, it relies heavily on ligaments to support
it. Knees can only move on one plain and it’s the ligament’s
job to prevent any other movements. This is unlike the shoulder
and the hip joint, which have their movements limited by the bones.
Knee ligament injuries always result in more serious long-term problems
than a fracture or a break. This is due to bones being able to regenerate
themselves to their previous strength: ligaments are unable to do
this. Knee injuries are quite often misdiagnosed as patients report
feeling something break: nothing shows up on a radiograph and they
are sent home. Usually if they feel a break and there is no bone
damage, then it is likely to be a major ligament rupture.
Anterior Cruciate Ligaments (ACL)
The ACL is one of four ligaments that connects the thigh to the
shinbone. These ligaments are there to stabilize and keep the knee
moving in a controlled manner. The MCL, the ligament down the inside
of your knee, works with the LCL, which is on the outside of the
knee, to stabilize the side-to-side movements. The other two ligaments
are deep inside the knee between the shinbone and the thigh. These
ligaments cross over each other at the back. The PCL connects the
thigh to the back of the shinbone, the ACL connects to the front
of the shinbone. They both control front-to-back stability. The
ACL also prevents the rotation of the shinbone and the excessive
forward movement of the shin in relation to the thigh.
ACL injuries usually happen as a result of falling awkwardly in
a tackle or the knee twisting in an unfamiliar way while trying
to change direction quickly. All the injuries are due to the ligament
being overstretched in the wrong direction and it either completely
snaps (rupture) or it tears. This snap makes a loud ‘pop’
noise from inside the knee. When ligaments rupture they cause the
blood vessels to rupture as well which fills the knee with blood,
causing excessive swelling. This does not always happen immediately
because ACL injuries can give players the impression they can carry
on but, as soon as the knee is put under any strain it becomes unstable.
A torn ACL is extremely painful immediately after the injury and
can result in widespread tenderness around the top of the shin and
the bottom of the thigh. If this occurs during a rugby match it
is crucial to stretcher off and avoid movement of the knee.
A classic cause of this injury in rugby would be if a tackle was
made from behind, down at the ankles. The foot would get stuck in
the ground and the weight would then cause excessive forward movement
of the shin in relation to the thigh due to the leg being bent.
Completely rupturing the ACL would prevent the player taking any
further part in the game.
Medial Collateral Ligament (MCL)
As previously stated, the MCL is on the inside of the knee and
stabilizes the side-to-side movements. Its function is to prevent
the widening and overstretching of the inner portion of the joint;
it tries to do this by resisting forces applied to the outside of
Ligament Injury Grading
Damage to the ligament can cause a strain of different severities.
These severities are graded and each grade shows the following side
- There is minor tearing of the fibres of the ligaments.
- Mild tenderness on the inside of the knee over the ligament
- Usually there is no swelling
- There is more extensive ligament damage
- Loses a bit of stability
- Significantly more tenderness especially around the inside
of the knee
- Slight swelling occurs.
- This is a complete rupture of the ligaments
- Shows severe instability
- Pain can vary; can sometimes be less painful than grade 2 tears.
(McRae & Kinninmonth, 1997)
Common Causes of Knee Injury
The most common occurrence of this injury in rugby is during a
side on tackle. The weight of the tackler causes the knee to stretch
inwards which causes the tear. This is not really preventable especially
with tackles being so unpredictable. This is more likely to occur
in forwards due to the high contact levels in such short areas.
For backs, MCL injuries occur usually when running with the ball:
the player’s boot can get planted in the ground and when he
tries to change direction, the foot doesn’t move, causing
the knee to buckle inwards.
With the nature of rugby being very physical with lots of contact,
it is not surprising that there are regular serious injuries. There
is scope for more research to be done in the field of rugby injuries
to try to prevent so many happening, especially looking into the
tackle and ways of trying to make it safer without ruining the game.
Also different training programmes should be considered in order
to prevent knee injuries occurring at the top level. If a club plays
one first-team match per week and one second-team match every other
week, they would have an average of two players unavailable to play
each week because of knee injuries (Dallalana et al. 2007). This
loss of player availability is a serious problem and will only be
improved following further detailed study.
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4th Ed. Cambridge: Churchill Livingstone.
Holtzhausen, L.J., Schewellnus, M.P., Jakoet, I., Pretorius, A.L.
(2006). The incidence and nature of injuries in South African rugby
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McRae, R., Kinninmonth, A.W.G. (1997) Orthopaedics and Trauma.
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