ACL and PCL tear Flashcards
what is the function of the ACL?
limits anterior displacement of the tibia relative to the femur. also contributes to knee internal rotational stability
how do ACL tears typically develop?
Hx of twisting the knee while weight-bearing
majority in athletes without contact (typically landing from a jump)
may also develop with application of large force to the back of the knee
How do patients with ACL injury present?
rapid swelling (ligament is highly vascular –> haemarthrosis)
significant pain
later patient describes leg as ‘giving way’
*lachman’s test
*anterior draw test
what investigations are performed?
X-ray (AP and lateral) –> exclude bone injury/joint effusion
MRI - also indicates meniscal tears - 50% have associated meniscal tears
what is the unhappy triad?
injury to ACL, medial meniscus and medial collateral ligament
develops due to strong force applied to the lateral aspect of the knee.
what management steps can be taken with ACL injuries?
immediate: RICE
conservative:
rehab with strength training of quads to stabilise the knee
surgical:
repair using tendon or artificial graft, however, the patient has prehabilitation with physio prior to surgery
what is the role of the PCL?
resists posterior tibial displacement and hyperflexion of the knee
how is the PCL usually damaged?
high energy trauma e.g. direct blow to the tibia in a road traffic accident.
what are the clinical features associated with PCL tears?
immediate posterior knee pain
instability
positive posterior draw test
what investigations are performed in suspected PCL injuries?
MRI
how are PCL tears managed?
conservatively:
knee brace and physio
surgical:
insertion of graft - indicated in recurrent instability/remains symptomatic
