Common hand deformities

Question 1

Boutonniere deformity

Answer 1

• flexion of PIP, hyperextension of DIP
• dorsal capsule and central slip of extensor mechanism disrupted, cause weak/absent extension at PIP. DIP forced into hyperextension by increased force of lateral bands

Question 2

Swan neck deformity

Answer 2

-hyperextension of PIP, flexion of DIP
(possible flexion of MCP)

• caused by (1) intrinsic muscle tightness; (2) stretching or rupture of terminal extensor tendon at DIP; (3) chronic synovitis leading to stretching of volar capsular supporting structures at the PIP
• loss of ability to make fist or hold small objects

Question 3

Mallet finger

Answer 3

• flexion of DIP

- rupture of terminal extensor tendon crossing DIP

Question 4

Nodes (2 types!)

Answer 4

• bony enlargements that indicate cartilage damage caused by OA. also seen in RA.
• hard to the touch, not typically painful
• at DIP: Heberden’s nodes
• at PIP: Bouchard’s nodes

Question 5

Nodules

Answer 5

• granulomatous and fibrous soft tissue masses that are sometimes painful
• usually along weight-bearing surfaces like ulna or olecranon

Question 6

Deviation

Answer 6

• change in normal joint position
• radial or ulnar
• RA: most common is radial deviation of wrist and ulnar deviation of MCPs)

Question 7

Subluxation

Answer 7

• volar or dorsal displacement of joints

- RA: most common sites are wrist and MCP joints

Question 8

Dislocation

Answer 8

• joints whose articulating surfaces are no longer in contact
• severe RA: volar dislocation of carpals on the radius or other dislocations can result from complete destruction of ligamentous integrity

Question 9

Ankylosis

Answer 9

• fusion of the bones of a joint
• lack of joint mobility
• can be bony or fibrous

Question 10

Extensor tendon rupture

Answer 10

• inability to actively extend a joint in the absence of muscle weakness
• extensor digiti minimi is often first to rupture
• EPB, EDC of 3rd, 4th, and 5th digits also vulnerable
• causes: (1) rubbing of tendon over bony surfaces; (2) damage to tendon from direct synovial invasion; (3) pressure that decreases blood supply to tendon

Question 11

Trigger finger

Answer 11

• inconsistent limitation of finger flexion or extension

- caused by nodule on a flexor tendon or stenosis of a tendon sheath–>impedes tendon’s ability to glide

Question 12

Mutilans deformity

Answer 12

• very floppy joints with redundant skin
• result: resorption of the bone ends, shortens the bones, renders joints completely unstable
• most common: MCP and PIP joints, radioulnar joints at wrists

Question 13

Thumb deformities

Answer 13

See Pedretti pg 1019