Bunnell Test (or Bunnell–Littler Test) is used to determine whether flexion restriction of the proximal interphalangeal joint PIP is due to tightness of the intrinsic muscles or due to a restriction of the metacarpophalangeal joint capsule.
This test is done in two stages, metacarpophalangeal joint MCP extension and flexion:
The metacarpophalangeal joint is stabilized in extension and the proximal interphalangeal joint is tried to flex and the degree of flexion is noted.
Then the metacarpophalangeal joint is flexed and again the degree of flexion of proximal interphalangeal joint is noted.
What does a positive Bunnell Test mean?
We differentiate 3 cases:
If the PIP flexion is increased, the pathology is intrinsic muscle contracture (Intrinsic tightness) as the intrinsic get released on MCP flexion.
If the PIP flexion is decreased, the pathology is extensor tendon contracture (extrinsic tightness) which is stretched further on MCP flexion.
If the PIP flexion is the same in both situations, the pathology is articular changes such as joint stiffness, tendon adhesions, and tenosynovitis
Increased pressure in the fascial compartments of the hand produces a typical deformity with slight flexion in the metacarpophalangeal joints, extension in the proximal and distal interphalangeal joints, intensification of the transverse arch of the hand, and adduction of the thumb (intrinsic plus deformity).
The Haines–Zancolli test is used to determine whether restricted flexion in the Distal interphalangeal joints (DIP joints) is due to a restriction of the PIP joint capsule or tightness of the oblique retinacular ligament. The test for a contracture of this ligament is the same as the Bunnel Littler test, only at the PIP and DIP joints.
The clinician positions and holds the PIP joint in a neutral position with one hand and attempts to flex the DIP joint with the other hand. If no flexion is possible, it can be due to either a tight retinacular ligament or capsular contraction.
The PIP joint is then slightly flexed to relax the retinacular ligament. If the DIP can now flex, the restriction is due to tightness in the retinacular ligament. If the DIP cannot flex, then the restriction is due to a capsular contraction.
The Haines-Zancolli test is helpful to aid in a decision of either conservative or surgical treatment. A positive Haines-Zancolli test result equates poor outcome with conservative treatment.
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