Knee Joint Effusion: Examination

A comprehensive clinical examination is the basis for selecting further diagnostic steps:

  • General physical examination – including blood pressure, pulse, body weight, height; furthermore:
    • Inspection (viewing).
      • Skin (normal: intact; abrasions/wounds, redness, hematomas (bruises), scars) and mucous membranes.
      • Gait (fluid, limping).
      • Body or joint posture (upright, bent, gentle posture).
      • Malpositions (deformities, contractures, shortenings).
      • Muscle atrophies (side comparison!, if necessary circumference measurements).
      • Joint (abrasions/wounds, swelling (tumor), redness (rubor), hyperthermia (calor); injury evidence such as hematoma formation, arthritic joint lumpiness, leg axis assessment) [phenomenon of “dancing patella”? Examination procedure: patient lies on a couch; the suprapatellar recess (bursa in the area of the knee joint) is smoothed out, after which the dancing patella (kneecap) can be detected when the kneecap is pressed in. The examiner feels the swimming of the patella in the effusion fluid (= positive ballottement)].
    • Palpation (palpation) of prominent bone points, tendons, ligaments; musculature; [joint (joint effusion); soft tissue swelling; tenderness (localization!)]
    • Measurement of joint mobility and range of motion of the joint (according to the neutral zero method: the range of motion is given as the maximum deflection of the joint from the neutral position in angular degrees, where the neutral position is designated as 0°. The starting position is the “neutral position”: the person stands upright with the arms hanging down and relaxed, the thumbs pointing forward and the feet parallel. The adjacent angles are defined as the zero position. Standard is that the value away from the body is given first). Comparative measurements with the contralateral joint (side-to-side comparison) can reveal even small lateral differences.
      • Examination of the knee joint (side-to-side comparison) – including blood flow, motor function, sensitivity; meniscus tests, drawer tests; especially examination of the patella (kneecap) – this is used to diagnose knee joint effusions. In larger effusions, palpation reveals a “dancing patella” that springs back elastically after frontal pressure! Furthermore, examination of the joint space (indication of e.g. meniscus injuries) and palpation (palpation) of the peripatellar tissue (tissue around the kneecap), which also serves to diagnose knee joint effusions.
  • Health check

Square brackets [ ] indicate possible pathological (pathological) physical findings.