Knee Injuries Flashcards by Laura Morgan

ACL injury mechanism

Valgus twisting e.g. forcefully landing on leg when attempting to rapidly change direction
Generally non contact

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Typical ACL injury presentation

Popping sound at the time of injury
Fall to the ground, unable to finish playing sports, need to be helped from the field.
Knee swells quickly. Unable to weight-bear.

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If no fracture acute knee swelling indicates…

ACL injury

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Mechanism of PCL injury

Direct blow to flexed knee

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Typical presentation of PCL injury

Posterior knee pain, a subtle limp, a modest effusion, and reduced end-of-range knee flexion.

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Mechanism of MCL/LCL injury

Significant varus or valgus strain. Normally requires contact injury.
Direct blow pushing knee sideways

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Typical presentation of MCL/LCL injury

Medial or lateral pain. Feeling of instability.
No significant swelling (as it is extra-articular)

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Is MCL or LCL injury more common?

MCL

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Mechanism of meniscal injury

Loaded knee is twisted

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Typical presentation of meniscal injury

Locking, blocking or catching
Mild effusion can develop

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What type of knee injury is caused by ACL type injuries / hyperextension and is commonly seen in children?

Tibial eminence #

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What type of knee injury is caused by jumping activities e.g. basketball, gymnastics, football and is commonly seen in adolescents?

Tibial tuberosity #

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Mechanism patella #

Direct blow to knee or forceful contraction of quad against semi-flexed knee

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Mechanism of tibial plateau #

Axial loading with varus or valgus stress
Falling onto an extended leg

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Typical presentation of tibial plateau #

Tenderness over medial or lateral margins of proximal tibia
Often unable to weight-bear
May be associated with knee ligament injuries

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Mechanism of patella dislocation

Twisting or direct blow on partially flexed knee

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Typical presentation of patella dislocation

Very painful knee in flexed position with laterally displaced patella. May have large effusion.

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Patella dislocations are more common in what age group

Adolescents

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Mechanism of knee dislocation

High energy trauma

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How common is knee dislocation?

Rare

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Why worry about knee dislocation?

Potentially limb-threatening
Neurovascular compromise needs to be ruled out

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Special tests on exam for ACL injury

Lachman and pivot shift tests

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Special tests on exam for PCL injury

Posterior drawer test and posterior sag

Special tests on exam for collateral ligament injury

Varus and valgus stress tests

Special tests on exam for meniscal injury

McMurray's test and Thessaly test

Special tests on exam patella instability (dislocation)

Patellar apprehension test

Suspect _________ in all major knee injuries (esp if significant deformity, swelling, and instability)

Knee dislocation

Check the integrity of the extensor mechanism by performing ________ as these injuries can be missed.

Straight leg raise

Check _____________ to rule out neurovascular compromise.

Pedal and popliteal pulses, motor function, and sensation distal to the injury

If large effusion consider...

Knee fracture Haemarthrosis suggestive of ligament or meniscal tears

Ottawa knee rules - any one of the following indicates xray following acute knee injury

≥55yo Tenderness at the head of the fibula Isolated tenderness of the patella Inability to flex knee to 90º Inability to bear weight (inability to take four steps regardless of limping) immediately and at presentation

Investigations after first patella dislocation

Arrange a knee AP lateral and skyline patella X-ray, looking for a fracture to the medial patella.

Is USS useful in acute knee injuries?

Not usually

Lipohaemarthrosis on xray indicates

Intra-articular #

Refer acutely to ortho in what situations?

Any knee fracture Knee dislocation Injury to the extensor mechanism of the knee Concerns about neurovascular status Acutely locked knee

Management if no # but swollen knee

Early physio → if not settling refer ortho

Management if stable knee injury without large effusion and no specific diagnosis

Ice and analgesia (paracetamol, NSAID) If effusion: RICE, tubigrip, crutches, physio and review in 2/52 If significant laxity, unable to weight bear or ongoing effusion at review → ortho If no swelling at any stage reassure significant injury unlikely

Acute management of ACL injury

Tubigrip (remove for sleep), RICE, consider crutches but recommend to weight-bear as able. First few days avoid twisting/jumping. If large effusion consider aspiration for pain relief Early physio

Aim of physio in ACL injury

Strengthening of quads/hamstrings + ROM exercises → will help reduce effusion, improve ROM and strength

Following ACL injury can take up to _________ to get back to sport

9 months

When to acutely f/up ACL injury

2/52 If exam positive for ACL injury → ortho

Surgical treatment of ACL injury can help prevent _____________

Further knee instability

When is surgery usually done for ACL injuries

Preoperative rehab important - surgery done when FROM + good strength (unlikely <3/52 post injury)

PCL and collateral ligament injuries - management if complete tear

Consider hinged brace

PCL and collateral ligament injuries - management if incomplete tear

Analgesia, RICE, tubigrip, crutches for a few days then mobilise as able

PCL and collateral ligament injuries - management if associated with other injuries (e.g. meniscal tear, cruciate rupture)

Refer ortho

When to f/up PCL and collateral ligament injuries acutely

Review 1-2 weeks. If significant laxity → refer ortho

Management meniscal tear

RICE, early physio and gradual mobilisation

Meniscal tear usually settles over what time period

6-8 weeks (refer ortho if doesn’t settle)

Management if acutely locked knee from meniscal tear

Most will unlock spontaneously with analgesia, rest and support → refer ortho

General advice about return to work and sports for minor knee injuries

Usually after 2 to 3 weeks

General advice about return to work and sports for complete ruptures

May be ≥6 weeks before returning to active sport

General advice about return to work and sports for lateral‑sided ligament injuries and ACL injuries

May require surgery, and more time off work and sport

Management of first patella dislocation and no # on xray

Physio

Management of second + subsequent patella dislocations

If pt would consider surgery → refer ortho OPC