PCL 11- ACL tear: anatomy, investigation and management

Anterior cruciate ligament

Anatomy

· Origin

o Anterior intercondylar area of tibia

· Attachment

o Posterior to the attachment of medial meniscus

· Function

o Weakest of the cruciate ligaments

o Limits posterior rolling of femoral condyles

o Prevents posterior displacement of femur on tibia

o At 90^o flexion, the knee cannot be pulled anterior because ACL prevents this

Investigation

· Physical examination (diagnosis is made with this and presenting complaint)

o Look and feel for swelling, inflammation

o The Anterior drawer sign

§ Flexing the knee at 45o, if the tibia can be pulled anteriorly it shows that ACL is ruptured

o Lachman’s test

§ Passively flex knee to 20-30^o, put one hand on calf while the other holds the leg above knee joint, thumb must be on tibial tuberosity

§ Pull tibia towards you, if the tibia move towards you, ACL torn is present

· X-rays

o To rule out possible bone fractures

· MRI

o Unsure about the extent of damage, the doctor might order MRI to check for partial or complete tears

· Arthroscope

o Check for damages

Grading

· grade I sprain: pain with minimal damage to the ligaments

· grade II sprain: more ligament damage and mild looseness of the joint

· grade III sprain: the ligament is completely torn and the joint is very loose or unstable.

Management

· Pain and first aid

o Immobilise, injured knee should be held in a splint

o Elevate joint, use NSAIDS or ice

· Surgery

o ACL Reconstruction surgery (for severe tears)

§ Done with autograft or allograft with and arthroscope

· Using hamstring tendon or patella tendon

§ New tendon is fixed into bone while it heals into the bone

§ Strong enough for sports in 6 months

o Surgeon Martha Murray at Children’s Hospital Boston reported that a collagen gel enriched with platelets can stimulate healing of partial ACL tears

§ 40% strength increase than 14% in ARS

· Rehabilitation

o Rest, ice, elevation, bandage

o Strengthening exercises

§ Bike riding, swimming…

o Is done before (to regain most range of motion, reduce swelling) and after surgery (recover strength)

Reference:

Moore and Dalley 5^th edition

http://www.mayoclinic.com/health/acl-injury/DS00898/DSECTION=treatments-and-drugs

http://www.mayoclinic.com/health/acl-injury/DS00898/DSECTION=treatments-and-drugs

http://www.melbourneorthopaedics.com.au/ligament.html#4

http://137.190.56.8/hthsci/casestudies/ACL/examination_of_theanterior_cruci.htm

http://www.med.umich.edu/1libr/sma/sma_ancrulig_sma.htm