Joint Exam

History

The joints of the human body that joined the bones into a whole skeleton have interested students of anatomy for centuries:

• Hippocrates (460 BC-370 BC) wrote on the “the articulations.”
• The Greek physician Apollonios of Kition wrote a work entitled Peri Arthron (On Joints) in the first century BC.

Description and Pathophysiology

The synovial joints of the hand and wrist are composed of bone, the ends of which are covered by articular cartilage. Normal articular cartilage allows low-friction joint motion. The joints are held together by a strong fibrous structure called the joint capsule, and the collateral ligaments and volar plate represent thickenings of this capsule. The internal surfaces of the joint that are not covered by the articular cartilage are lined by synovial tissue, and the synovium is composed of two layers:

• Intimal layer: responsible for the production of synovial fluid
• Outer layer: the fibrous sublining layer that attaches to the joint capsule^{1, 2}

The hand and wrist contains several types of joints that allow various arcs of motion, which depend on the joint structure and design:

• The thumb interphalangeal (IP) joint and finger distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints are uniaxial hinge (ginglymoid) joints. These joints allow the phalanges to have a flexion/extension arc of motion.
• The metacarpophalangeal (MP) joints of the fingers and thumb are multiaxial condyloid joints. These ellipsoid-shaped joints allow arcs of motion in the flexion/extension and abduction/adduction planes, and to a lesser degree, in the pronation/supination (rotational) plane. The shape of the finger metacarpal head accounts for the “cam effect,” which allows abduction and adduction when the joint is in extension and little motion in the abduction/abduction arc when the MP joint is flexed. This explains the need to test MP joint collateral ligament stability in flexion.
• The thumb carpometacarpal (CMC) joint is a sellar joint with articular surfaces that are convex in one plane and concave in another. This saddle-like joint design allows motion in several planes, including the flexion/extension, abduction/abduction, and pronation/supination (rotational) planes.³
• The wrist joint is a complex structure made up of multiple smaller joints. The major joints of the wrist are the sum of multiple smaller joints between the carpals, metacarpals, radius, and ulna. Its primary functional joints are the radiocarpal joint, midcarpal joint, and distal radial ulnar joint. Collectively, these joints provide the wrist with motion in the flexion/extension, radial/ulnar deviation, rotational (circumduction), and dart-thrower motion planes.^4-6

Instructions

The examination of a specific joint should follow these 5 steps:

1. Inspection (ie, observation)
   • The examiner should look for signs like these:
     • Redness around the joint
     • Swelling – creases can be hard to detect secondary to swelling
     • Joint angulation
     • Joint deformity – acute examples include dislocations of fracture involving the joint.  Chronic deformity could be secondary to arthritis, tumor, or congenital abnormalities.
   • When the examiner inspects the joint, the uninjured or uninvolved opposite joint should always be viewed and used as a “normal” baseline.
2. Palpation (including for localizing tenderness)
   • First step in the joint examination. While palpating the joint, the examiner can detect abnormal warmth in the skin surrounding the joint, which can indicate the presence of a septic or inflamed joint secondary to diseases like gout or an exacerbation of rheumatoid arthritis.
   • Can also allow for assessment of joint swelling associated with a joint effusion or associated joint synovitis. Crepitus may be palpated in the joint when synovitis or arthritis is present. The synovitis can be graded from 0-3, with Grade 0 being normal and Grade 3 indicating profound extensive synovitis.⁷ As noted, crepitus can be associated with synovitis or with intermittent joint locking, which may indicate the presence of a loose body in the joint.
   • Next, careful joint palpation can identify areas of localized joint tenderness. The exact location of joint tenderness can provide useful information that helps define a specific joint injury. For example, tenderness over the radial collateral ligament may indicate a recent collateral sprain, while tenderness over the extensor tendon at the DIP joint may indicate a mallet finger injury. Palpating around the joint is also critical for identifying osteophytes, pathological tumors, and/or cysts associated with the joint, such as a mucoid cyst at the DIP joint.
3. Joint stability assessment
   • After a thorough inspection and careful palpation of the joint, joint stability should be tested next, which is done by stressing the collateral ligaments and volar plate of the involved joint. This joint stability examination should help diagnose acute and/or chronic joint instability.^1-3
4. Range of motion (ROM) and muscle/tendon function assessment
   • Passive and active ROM of the joint, and assessing the muscles and tendons that provide the power to actively move the joint. While determining ROM, the examiner should also define patients with excessive motion that may suggest the presence of hyperligamentous laxity. The associated muscle examination should also determine the strength of the muscles surrounding the joint using a muscle testing scale from 0-5. Finally, the examiner should note if there is any tenderness or pain elicited by the joint when moving through its functional arc of motion. Pathologic joints typically demonstrate pain with motion.
5. Specialized joint-specific examination signs and tests
   • The final part of the joint examination is performing specialized tests that are used for specific joints and clinical situations. One example is the thumb CMC compression (grind) test, which is used to determine if thumb CMC joint osteoarthritis is present. Another example is the Watson Sign, which is useful for defining a scapholunate ligament tear in the wrist and the carpal instability associated with this ligament injury.

Related Signs and Tests

• Collateral ligament examination
• Volar plate examination
• Extensor tendon examination
• Flexor tendon examination
• Skin examination
• Muscle testing
• Thumb CMC grind test
• The Watson Sign