Chapter: Medicine Study Notes : Musculo-Skeletal


Locking: question carefully to distinguish from pain-induced hamstring spasm





·        About the injury


o  How did you do it: Direct blow or indirect (eg twisting ® consider meniscus lesion)


o  Immediate disability: Inability to walk, knee collapsing (?ACL injury), locking (?meniscus), catching, clicking. For days or weeks, hamstring spasm protects the painful knee. As pain and effusion settle, the knee gradually straightens. NB neither cartilage or inner two thirds of menisci are innervated – pain from these injuries is caused by consequential tension/damage to other structures

o  Sounds and sensations: hearing or feeling a pop, snap or tearing


o  Swelling: If the knee swells straight after an injury ® ?ACL injury causing bleeding into the joint or other haemarthrosis (always serious). Soft tissue swelling/effusion takes up to a day


·        Always ask about knees:

o  Locking: question carefully to distinguish from pain-induced hamstring spasm

o  Giving way

o   Swelling

·        Function:

o   Difficulty with stairs (going up or down?)

o   Trouble getting out of low chairs

o   Waking with pain at night after having leg bent




·        Adequately expose the leg

·        Walk:

o   Stiff knee gait

o   Valgus deviation (deviation away from midline, eg knock knee – Genu valgus)

o   Varus deviation (deviation towards midline, eg bow leg – Genu varum) 

o   Lateral thrust: Posterolateral insufficiency, knee goes posterolaterally, a result of Medial Compartment OA.

o   Squat on their haunches and duck walk:

§  Stimulates pain in the front then it is an anterior problem (ie patello-femoral joint) 

§  In the popliteal fossa ® could be a medial meniscal tear.

o   View from the side: any fixed flexion deformity

o   Inspect the popliteal fossa (then you don‟t have to get them to roll over on the bed). Look for

o   Baker‟s cyst – protrusion of the synovium into the popliteal fossa

·        Look: Get on bed

o   Swelling

o   Muscle wasting: measure thigh circumference

o   Bony deformity

o   Arthroscopy scars

o   Get them to push their knee down into the bed to test:

§  Extension (fixed flexion deformity)

§  For muscle wasting in vastus medialis

o   Can measure angles with a goniometer

·        Feel:

o   Feel for temperature compared with rest of leg and with other knee

o   Feel for effusion (Meniscal pathology often produces an effusion)

§  Stroke/bulge test

§  Patellar tap 

o   Palpate joint line along tibial plateau (watch their face): Tenderness here may indicate a meniscal tear, above or below the joint line the meniscus won‟t be causing it.

o   Palpate medial and lateral collateral ligaments

o   Palpate tibial tuberosity and infra-patellar ligament


·        Move:


o   Actively raise their leg straight as high as they can: checks extensor mechanism – quads, patella ligament, etc. If damaged traumatically then urgent surgery (the key knee injury where you wouldn‟t wait for the swelling to go down before operating) 

o   Flex their knee. Bring the other leg up with the knee in flexion to compare. Have one hand on the patella to feel for crepitus. Measure distance from heel to buttock

o   Poster Cruciate Ligament:

§  Feet back down on the bed leaving both their knees in 90o flexion.

§  Look across the two knees for posterior sag, which could indicate a PCL rupture. 

§  Stabilise the tibia (sit on their foot), relax hamstrings and push tibia towards body (Posterior draw test)

o   Anterior Cruciate Ligament:


§  Anterior draw to test the ACL. Compare with the other side. Sit on foot and pull tibia towards you 

§  Lachman‟s Test: with leg in slight flexion on the bed (eg rolled up towel or your knee underneath it) push down on distal femur while pulling up on proximal tibia 

§  Pivot Test (hard to elicit unless relaxed or under GA): Flex the knee, put it in valgus, then extend it. If ACL is ruptures, the knee jumps smartly forward


o   McMurray‟s Test for meniscal tears (not particularly reliable): Feel and listen for a click as meniscal tag snaps free

§  Start with leg in slight flexion

§  Medial lemniscus: externally rotate the tibia on the femur, apply valgus pressure. Extending the leg will cause pain/clicking 

§  Lateral lemniscus: internally rotate the tibia on the femur, apply varus pressure. Further flexing the leg will cause pain/clicking

o  Collateral Ligaments:

§  With leg under your arm Valgus stress test and Varus stress test:

·        With the knee still in 15o steady it as you pull the leg into valgus, this tests the medial collateral ligament and the ACL. Now Push it into Varus, this tests the lateral collateral ligament 

·        Lay the leg flat and repeat with the knee in full extension: tests all structures – not just the collateral ligaments. If laxity in full extension, the ACL or PCL damage as well


·        Patellar-femoral joint:

o  Ask about pain going up and down stairs

o  Palpate

§  Border

§  Anterior surface: Push it in – „any pain?‟

§  Tendon and ligament insertions (especially tibial tuberosity)

§  Posterior surface (by pushing it to one side and then the other) 

§  Solomon‟s test: With leg in full extension, try and lift patella and get fingers underneath. If can‟t then effusion/synovitis


o  Site on edge of bed with legs handing over: Look at the direction that the patellar points in. Have the patient flex and extend at the knee ® should follow an inverted J course

o  Grind or Friction Test

§  Straighten the leg with your hand over the patella

§  Will cause painful grating if the central portion of the articular cartilage is damaged


o  Patella apprehension test: Press the patella laterally and hold it slightly subluxed ®Watch the person‟s face and ask them to flex their knee ® If they grimace or show signs of pain then the test is positive and is diagnostic of recurrent patellar subluxation or dislocation.


·        Joint Above and Below. Check the Hip (pain is referred to the knee from there)

·        Check the Ankle and the foot pulses, and distal neurology


Knee Injury


·        General principles of ligament injury: 

o  Pain + slight joint opening Þ good (strain/partial rupture)

o  No pain + big joint opening Þ bad (complete rupture)

·        Always x-ray adequately.  Small bony fragments on x-ray Þ soft tissue injury until proven otherwise

·        In kids, bone and growth plates are weaker than ligaments

·        Meniscal Tears:

o  Variety of types: fragments causing locking, tears on internal or external margins, etc

o  Clinical: Twisting injury, unable to straighten knee, locking (typically bucket handle tears), pain

o  Investigations: Arthroscopy or MRI

o  Management: Excise tears or reattach.  Aim is to preserve as much of the meniscus as possible

·        Lateral/Medial Collateral Ligament:

o  Most common knee ligament injury 

o  Medial is attached to the medial meniscus. Lateral isn‟t ® less injury. But if it is, consider check for fibular head fracture and common peroneal nerve damage 

o  Mechanical: Blow to medial/lateral side of knee pushing the joint into varus/valgus 

o  Presentation: Tenderness over ligament (unless complete rupture ® no pain), pain worse under varus/valgus stress, effusion 

o  Management: Isolated tears heal well without operating. Immobilisation in leg plaster at 10º flexion (6 weeks) then mobilise cautiously. May have ongoing instability

·        Anterior Cruciate Ligament: 

o  Prevents posterior displacement of the femur on the tibia and hyperextension. Is the weaker of the 2 cruciates. Anterior-medial bundle is taut throughout flexion ® anterior draw test +ive if AMB affected 

o  75% of haemarthroses

o  Mechanism: sharp twisting movement or tackle that pushes the tibia forward cf femur 

o  Presentation: may hear a snap, swelling, pain, effusion (very rapid if due to haemarthrosis). If delayed then knee gives way, can run in a straight line but can‟t turn corners

o   Often tear medial meniscus (® OA and instability)

o   X-ray for avulsion fracture of tibial insertion: seen in young patients

o   Management:

§  Conservative: aspirate and physio to strengthen hamstrings 

§  Surgical: reconstruction of ligament (repair impossible as ligaments devitalise rapidly after injury)

·        Posterior Cruciate Ligament:

o   Prevents anterior displacement of femur on tibia and hyper-flexion

o   Mechanism: blow to anterior tibia when knee flexed (eg bicycle vs car) or hyperextension

o   Presentation: swelling, pain, effusion, posterior sag at 90º flexion 

o   X-ray for an avulsion fracture (® requires surgery) 

o   Most do well with conservative treatment. Can often manage without a PCL. Quads exercises decrease backwards tibial sag

·        Patella Fractures: 

o   Comminuted: from blow to flexed knee (eg knee against dashboard). Put patella together (usually hard) or remove it (patellaectomy)

o   Stellate: blow to patella that cracks but doesn‟t displace fragments.  Aspirate + long leg cast

o   Transverse: Due to sudden contraction of quads.  Internal fixation with tension wire band

·        Chondromalacia Patellae: young women. Patellar aching after prolonged sitting due to softening or

·        fibrillation of the patellar articular cartilage.  Conservative treatment: vastus medialis strengthening

·        Disruption of extensor mechanism: 

o   Rupture of Rectus Femoris: sudden violent contraction ® transverse tear.  Feel defect in muscle. 

o   Conservative treatment: ice, elevation, analgesia, mobilisation within limits of comfort. Functional deficit negligible 

o   Ruptured Quadriceps tendon: sudden violent contraction.  Need to reattach

o   Ruptured patella tendon: Forced flexion injury.  Repair if weakness or extensor lag

o   Dislocation of the Patella: 

§  Sharp twisting motion on flexed knee or blow to side of leg ® haemarthrosis (® swelling) and medial tenderness (medial structures torn). 

§  To reduce: gently extend the knee, then gentle traction. Primary concern is distal circulation ® reduce at scene of injury if possible

§  Aspirate and irrigate if necessary, splint for 4 weeks

§  Physio to strengthen quads (necessary for patella stability)

§  If recurrent then ?underdevelopment of lateral femoral condyle

·        Osteochondral Fractures: 

o   In young person, twisting or direct blow can ® detachment of sliver of bone and cartilage. Most common with patellar dislocation 

o   ® Haemarthrosis and fat from cancellous bone causing a fat-fluid line on lateral radiograph

o   If small then remove, if large then reattach 

·        Chondral separations or flaps: Fragments of articular cartilage. Need arthroscopy or MRI. Flaps are usually ground away. Separations are removed

·        Osteochondritis Dissecans: 

o   ¯Blood to subchondral bone (cause unknown) ® focal necrosis of cartilage and bone ® loose fragment 

o   Presentation: pain in young adulthood, worse on walking and hyperextension, M>F, intermittent swelling, maybe locking

o   X-ray: small irregularities on medial condyle +/- fragments

o   Treatment: wait, or surgery if no radiological signs of union

·        Bursitis: 16 bursae around the knee.  Most commonly affected are:

o   Prepatellar bursa: „housemaid‟s knee

o   Infrapatellar bursa: „Vicar‟s knee‟ – they kneel more upright 

o   Anserine bursae: on medial side of the head of the tibia, under the ligaments of semi-tendonosis, gracilus and sartorius

o   Aspiration distinguishes friction bursitis from infective or inflammatory bursitis

·        Haemarthrosis of the knee is the most common presenting complaint of a 0% F VIII haemophilia


Management of knee injury


·        ¯Weight

·        Exercises to strengthen hamstrings and quads (eg straight leg raise while seated)

·        Check for flattened arches ® exercises

·        Aquajogging

·        Analgesics (NSAIDs, consider COX2) 

·        If tense haemarthrosis then aspiration will give immediate relief and aid diagnosis (ie send it to the lab: ?blood, infection or gout)


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