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Knee examination / Osteoarthritis of the knee

Approach

  • Adequately expose both lower limbs
  1. Look
    • Walking aids
    • Alignment - varus / valgus
    • Quadriceps wasting
    • Scars - arthroscopic ports, meniscectomy, midline longitudinal incisions
    • Swellings
  2. Gait
    • Antalgic -
    • "Stiff knee" gait - pelvis rises to allow leg clearance during swing phase#
    • Instability "thrust" gait - mechanical or neuropathic
  3. Measure
    • Quadriceps wasting - measure thigh circumference at set distance (15cm above superior pole of patella, compare with opposite side)
  4. Feel
    • Temperature - use back of hand
    • Effusion test
      1. swipe test
      2. patellar tap
    • Tenderness - feel around joint margin, patella
      1. Grind test: move patella up and down while pressing gently against the femur - painful grating indicative of patello-femoral osteoarthritis
      2. Clarke's test:
    • Feel behind knee for any popliteal fossa swellings
  5. Move
    • Active (block to extension implies meniscal or cruciate injury)
      1. Extension / hyperextension
    • Passive
      1. Extension / hyperextension
      2. Flexion - normally flexes until calf meets hamstring: 140'
    • Component
      		 Test Significance
      Cruciates
      • Flex knees to 90' (keep feet flat on couch), Look for sag sign
      • Anterior draw test: flex knee to 90', sit on foot to stabilise (ensure foot is not tender) an pull forwards
      • Posterior draw test: flex knee to 90', sit on foot to stabilise and push backwards
      • Lachman test - for ACL injury
        1. Flex knee to 20' and hold distal thigh firmly with hand
        2. press down on distal thigh of patient and lift proximal tibia forwards
      		Grading of draw tests:
      • 1+: 0 - 5mm
      • 2+: 6 - 10mm
      • 3+: 11 - 15mm
      • 4+: >15mm
      Collateral ligaments
      • Tuck patient's foot under arm and flex knee to 20-30'
      • Apply varus / valgus force
      • Repeat test with knee in full extension (instability signifies a combined collateral and cruciate ligament injury
      		  
      Menisci
      • McMurray's test: differentiate between medial and lateral meniscal tears
      • Medial meniscus: flex knee, palpate medial joint line, externally rotate, extend knee
      • Lateral meniscus: flex knee, palpate lateral joint line, internally rotate, extend knee
      • Positive if: click or pain
      		  

Completion

  1. Examine joint above and below (hip, ankle)
  2. Assess neurovascular status of the limb
  3. Ask how problem affects life

Radiological changes in OA

  • Loss of joint space
  • Osteophytes
  • Subchondral sclerosis
  • Subchondral cysts

 

 

 

Treatment options in Osteoarthritis

  1. Lifestyle
    • Weight loss
    • Dietary modification
  2. Physiotherapy
    • Quadriceps strenghtening exercises
  3. OT: appropriate devices to aid mobility
    • Sticks
    • Frames
  4. Medical
    • Analgesics
    • Intra-articular steroid injection - temporary relief, problems of progressive cartilage destruction and bone destruction
    • Vesicosupplements: intra-articular injections of hyaluronic acid
  5. Surgical
    • Arthroscopic debridement and washout - temporary, for young patients
    • Patellectomy
    • Realignment osteotomy
    • Unicompartmental knee replacement
    • Total knee replacement
    • Arthrodesis: salvage procedure, if there is strong contraindication to sugery (sepsis)

Complications of knee replacement

  1. Intraoperative
    • Fracture of tibia
    • Vascular injury
  2. Immediate
    • Bleeding
  3. Early
    • DVT / PE / FE
    • Nerve palsy
    • Infection
  4. Late
    • Infection / loosening
    • Instability

Rheumatoid arthritis of the knee

Stage 1: proliferative
  • Palpable effusions and thickened synovium but stable joint
  • Posterior capsule at risk of rupture
  • Acute rupture of Baker's cyst
Stage 2: destructive
  • Increased instability of the knee joint
  • Marked muscle wasting
  • Some loss of flexion and extension
Stage 3: reparative
  • Severe pain and instability - may be marked stiffness or severe instability
  • Commonest deformities are fixed flexion and valgus
  • Instability manifests as increased AP glide and lateral wobble

 

Surgical options in the treatment of Rheumatoid disease of the knee

  1. Synovectomy + debridement
    • For failed medical treatment
    • Can be performed arthroscopically and involves removing the articular pannus and cartilage
  2. Supracondylar osteomy
    • Useful if knee is stable and pain-free but troubled by deformity
  3. Total Knee Arthroplasty
    • For advanced joint destruction

Haemarthrosis

  1. Primary spontaneous
    • Occurs without trauma
  2. Secondary
    • Trauma
    • 80% ACL injury
    • 10% patellar dislocation
    • 10% meniscal tears
    • Disorders of coagulation
    • Vascular malformations

Injury Anatomy Mechanism  Consequences  Treatment 
ACL
  • Intracapsular
  • From medial aspect of lateral femoral condyle inserts into anterolateral aspect of the medial tibial plateau
  • Stops tibia from moving forward in releation to the femur
  • Consists of 2 bundles, anteromedial (tight in flexion) and posteriolateral (tight in extension) 
  • Valgus/external rotation, hyperextension, deceleration and rotational movements
  • Patient hears a pop 
  • Inability to continue
  • Haemarthrosis
  • Abnormal knee movements leading to other injuries - OA, meniscal tears, MCL injury 
  • Non-surgical: physiotherapy
  • Surgical: Intra-articular reconstruction
PCL
  • Intraarticular but extrasynovial
  • Broad origin forming semicircle on lateral aspect of the medial femoral condyle
  • Inserts in a depression 1cm inferior to the articular surface on the posterolateral aspect between the medial and lateral tibial plateaus
  • Stops tibia from moving backwards
      
Meniscal tears

Medial Meniscus

  • Semicircular
  • Anterior horn attaches to anterio intercondylar fascia of the tibia anterior to the ACL tibial insertion
  • Posterior horn attaches posteriorly to the intercondylar fasica between PCL tibia insertion
  • Bound to joint capsule peripherally
  • Bound to femur and tibia at its midportion by the deep medial collateral ligament 

Lateral meniscus

  • Nearly circular
  • Covers greater area of tibial articular surface than the medial meniscus
  • Anterior horn attaches to tibial eminence behind ACL insertion 
    
  • Treatment depends on age, chronicity of injury, activity requirements, location,type and lenght of tear
  • Arthroscopy
  • Partial meniscectomy
  • Meniscal transplant

Causes of Locked Knee

  1. Childhood
    • Discoid meniscus
    • Pathology of the hip
    • Femoral condyle dysplasia
  2. Adolescent
    • Meniscal tear
    • Cruciate ligament injury
    • Osteochondritis dissecans
    • Synovial chondromatosis
  3. Adult
    • Meniscal tear
    • Cruciate ligament injury
    • Loose body
    • Osteochondral fracture
    • Synovial chondromatosis
  4. Elderly
    • Meniscal tears
    • Loose body
    • Intra-articular tumour
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