They are also common sites of serious tears, particularly in athletes.
The PCL prevents the tibia from moving backward too far.
They control the side-to-side motion of the knee.
Barry Austin / Digital Vision / Getty Images
The MCL is on the inside, and the LCL is on the outside.
Where they tend to differ is the extent of the injury and the severity of symptoms.
Because it’s smaller and weaker than the PCL, the ACL is more likely to sustain acomplete tear.
When this occurs, there may be an audible “pop” at the moment the ligament ruptures.
Both ACL and PCL tears generally cause knee pain.
Swelling may occur with ACL and PCL injuries and often develops quickly.
Swelling within the joint happens when a structure within the joint is damaged and bleeds.
The swelling may make the knee very difficult to bend.
Both ACL and PCL tears may cause knee instability.
PCL tears often occur with other knee ligament injuries.
Isolated PCL tears are uncommon.
MostPCL injuriesare partial tears.
Swelling is likely to happen almost immediately, but there will be relatively less pain, if any.
Fewer than 20% of knee ligament injuries involve the PCL.
Causes
Both ACL tears and PCL tears can result from a sports mishap.
Landing awkwardly from a jump can also damage the ACL.
Being a woman also is a risk factor for ACL tears.
The healthcare will check for areas of tenderness and swelling within the joint.
Range of motion (ability to fully straighten and bend the knee) will be evaluated.
Other physical exam tests will be done to check for signs of a meniscus tear.
X-rays are done to evaluate for other injuries, such as a fracture or dislocation.
X-rays are typically done prior to orderingmagnetic resonance imaging (MRI).
Complete ligament tears cannot be seen on X-rays.
Severity grades are:
The minimum treatment is usually physical therapy and a knee brace.
Complete tears may requirearthroscopic surgeryandligament reconstruction.
Not everyone with a complete ACL rupture will need surgery.
Canale ST, Beaty JH.
(2012)Campbell’s Operative Orthopaedics(12th Ed).
Maryland Heights, Missouri: Mosby/Elsevier.
Lee BK, Nam SW.Rupture of Posterior Cruciate Ligament: Diagnosis and Treatment Principles.Knee Surg Relat Res.
2017 Sep-Oct;51(5):563-75. doi:10.4103/ortho.IJOrtho_245_17
