Ahlbäck classification of knee osteoarthritis

• autoimmune
  • seronegative spondyloarthritides
    • ankylosing spondylitis
      • bamboo spine
      • dagger sign
      • hatchet sign
      • shiny corner sign
    • enteropathic arthritis
    • psoriatic arthritis
      • arthritis mutilans
      • ivory phalanx
      • pencil-in-cup deformity
    • reactive arthritis (Reiter syndrome)
    • undifferentiated spondyloarthritis
    • signs
      • Andersson lesion
      • Romanus lesion
      • vertebral body squaring
  • juvenile idiopathic arthritis
  • lyme arthritis
  • rheumatoid arthritis
    • musculoskeletal manifestations of rheumatoid arthritis
      • Boutonniere deformity
      • hitchhiker thumb deformity
      • Z deformity
      • rheumatoid nodule
    • pulmonary manifestations
      • rheumatoid pulmonary nodule
  • robust rheumatoid arthritis
  • systemic lupus erythematosus
    • Jaccoud arthropathy
• degenerative
  • osteoarthritis (mnemonic)
    • post-traumatic osteoarthritis
    • erosive osteoarthritis
      • gull-wing appearance
    • grading
      • Kellgren and Lawrence system
      • osteoarthritis of the hip - grading
      • osteoarthritis of the knee - grading
        • Ahlbäck classification
    • rapidly destructive osteoarthritis of the hip
    • osteoarthritis of the hand
      • Bouchard nodes
      • Heberden nodes
    • osteoarthritis of the knee
    • scaphotrapeziotrapezoidal (STT) arthritis
    • osteoarthritis of the vertebral column
    • osteoarthritis of the TMJ
  • primary cystic arthrosis of the hip
  • secondary synovial osteochondromatosis
• depositional
  • amyloid arthropathy
  • crystal arthropathy
    • calcium pyrophosphate dihydrate deposition disease (CPPD)
    • gout
    • ​​hydroxyapatite crystal deposition disease (HADD)
      • Milwaukee shoulder
  • haemophilic arthropathy
    • Arnold-Hilgartner classification
• infectious
  • septic arthritis
  • tuberculous arthropathy
    • Phemister triad
    • shoulder tuberculous arthropathy
• miscellaneous disorders
  • avascular necrosis
  • osteochondral defects
  • primary synovial osteochondromatosis
• related articles 
  • erosive arthritis (differential) 
  • joint ankylosis (differential)
  • monoarticular arthropathy
  • polyarticular arthropathy
  • monoarthritis (differential)

The knee is a complex synovial joint that can be affected by a range of pathologies:

• bone and cartilage
  • knee fractures
    • distal femoral condyle fracture
    • tibial plateau fracture (classification)
    • patella fracture
    • avulsion fractures of the knee
      • arcuate complex avulsion fracture (arcuate sign)
      • anterior cruciate ligament avulsion fracture
      • biceps femoris avulsion fracture
      • iliotibial band avulsion fracture
      • patella fracture
        • quadriceps tendon avulsion fracture
        • patellar sleeve fractures
      • posterior cruciate ligament avulsion fracture
      • reverse Segond fracture
      • Segond fracture
      • semimembranosus tendon avulsion fracture
      • Stieda fracture
        • Pellegrini-Stieda lesion
        chronic avulsion injuries
        • Osgood-Schlatter disease
        • Sinding-Larsen-Johansson disease
        • jumper's knee
  • dislocation
    • knee dislocation (Schenck classification)
    • patellar dislocation
  • chondromalacia patellae
  • osteoarthritis of the knee
    • Ahlback classification system in assessing osteoarthritis of the knee joint
    • Kellgren and Lawrence system for classification of osteoarthritis
    • MRI Osteoarthritis Knee Score (MOAKS)
  • osteochondral defects
  • osteochondritis dissecans of the knee
  • pattern of bone contusion in knee injuries
    • contrecoup injury of the knee
• ligaments
  • anterior cruciate ligament tear
    • anterior tibial translocation sign
    • deep lateral sulcus sign
    • positive PCL line sign
    • reconstruction
      • radiographic evaluation
      • complications
        • cyclops lesion
        • tibial tunnel cyst
  • anterior cruciate ligament ganglion cyst
  • anterior cruciate ligament mucoid degeneration
  • posterior cruciate ligament tear
  • medial collateral ligament tear
  • lateral collateral ligament tear
  • medial patellofemoral ligament tear
  • posterolateral corner injury
  • posteromedial corner injury
• tendons
  • patellar tendon rupture
  • quadriceps tendon rupture
• meniscal lesions
  • meniscal tear
    • longitudinal tear
      • horizontal tear
      • longitudinal tear
        • Wrisberg rip
    • radial tear
    • root tear
    • displaced tear
      • flap tear
      • bucket-handle tear
      • parrot beak tear
    • signs
      • absent bow tie sign
      • double PCL sign
      • Jack and Jill lesion
      • two-slice-touch rule
    • MRI grading system for meniscal signal intensity
  • meniscal contusion
  • ​meniscal/parameniscal cyst
  • meniscal flounce
  • meniscal fraying
  • meniscal maceration
  • meniscocapsular separation
    • ramp lesion
  • floating meniscus
• bursosynovial lesions
  • infrapatellar bursitis
  • pes anserinus bursitis
  • prepatellar bursitis
  • medial patellar plica syndrome
• fat pad
  • fat pad impingement syndromes
    • Hoffa disease
    • quadriceps fat pad impingement syndrome
  • Hoffa fat pad herniation
• popliteal fossa
  • popliteal artery entrapment syndrome
  • popliteal artery aneurysm
  • popliteal (Baker) cyst
• fascia
  • iliotibial band syndrome
• alignment
  • knee
    • genu recurvatum
    • genu varum
    • genu valgum
  • patellofemoral
    • patellar instability
      • trochlear dysplasia
        • crossing sign
        • double contour sign
        • sulcus angle
    • patella alta
    • patella baja
    • indices
      • Blackburne-Peel ratio
      • Caton-Deschamps index
      • Insall-Salvati ratio
      • modified Insall-Salvati ratio
• gamut
  • anterior knee pain
  • cyst-like lesions around the knee
  • extensor mechanism of the knee injuries