ACL and PCL tears Flashcards
what is the role of the ACL?
The ACL is an important stabiliser of the knee joint, being the primary restraint to limit anterior translation of the tibia (relative to the femur) and also contributing to knee rotational stability (particularly internal).
Consequently, a tear of this important ligament often results in significant functional impairment of the joint.
what is the aetiology of an ACL tear?
occurs in an athlete with a history of twisting the knee whilst weight-bearing.
The majority of ACL injuries occur without contact and result from landing from a jump, with the athlete not be able to continue playing thereafter.
what are the clinical features of an ACL tear?
- rapid joint swelling
(This is due to the ligament being highly vascular, hence the damage to the ligament results in a haemarthrosis, being clinically apparent within 15-30 minutes)
- significant pain
- instability, leg ‘gives way’
what clinical tests can identify potential ACL damage?
Lachman test and anterior draw test
what are your differentials for an ACL tear?
Fracture
Meniscal tear
Collateral ligament tear
Quadriceps or patellar ligament tear
what investigations are done into an ACL tear?
plain film radiographs of knee should be done to exclude any bony injurys/ joint effusion/ lipohaemathrosis present
MRI scan knee is gold standard to confirm diagnosis
will also pick up any associated meniscal tears
how is an ACL tear managed initially?
RICE
rest
ice
compression
elevation
how is an ACL tear managed conservatively?
involves rehabilitation, which utilises strength training of the quadriceps to stabilise the knee.
In the emergency setting, inpatient admission is rarely required; the patient can often fully weight bear and a canvas knee splint can be applied for comfort.
how is an ACL tear managed surgically?
involves the use of a tendon or an artificial graft. This will always follow a period of ‘prehabilitation’, whereby the patient will engage with a physiotherapist for a period of months prior to the surgery.
what are some complications of ACL injury and reconstructive surgery?
Post-traumatic osteoarthritis is a well-established complication of both ACL injury and ACL reconstructive surgery.
what is the role of the PCL and how do PCL tears occur?
PCL is the primary restraint to posterior tibial translation and works to prevent hyperflexion of the knee.
PCL tears typically occur in high-energy trauma e.g a direct blow to the proximal tibia
what are the clinical features of a PCL tear?
immediate posterior knee pain. There will be an instability of the joint and a positive posterior draw test (with a posterior sag) on examination.
how is a PCL tear diagnosed?
MRI scan is gold standard
how is a PCL tear treated?
can often be treated conservatively in the first instance with a knee brace and physiotherapy.
If the patient continues to be symptomatic and has recurrent instability of their knee joint then they may require surgery with insertion of a graft.
