HPI: Young male presents after a fall while skiing with right shoulder and wrist pain.

PE: Obvious deformity of the right wrist. No abrasions or ecchymosis. Full thumb abduction, able to flex at DIP and PIP joint of all 5 fingers, full abduction of all 4 palmar fingers, 5/5 strength to finger grip. Unable to range wrist, elbow or glenohumeral joint secondary to pain. Normal sensation to pinprick and two point discrimination of all five fingers. 2+ radial pulse with normal cap refill.  

Imaging:

Anatomy:
-    Normal wrist anatomy consists of two rows of bones:
      o   Proximal row: Scaphoid, lunate, triquetrum, pisiform
      o   Distal row: trapezium, trapezoid, capitate, hamate
-    Ligaments of the wrist:
      o   Interosseous ligaments run between the carpal bones and stabilizes proximal carpal bones.
      o   Intrinsic ligaments insert and originate among the carpal bones to internally stabilize them.
      o   Extrinsic ligaments connect radius and ulna to the carpus. 

How to make diagnosis:

• Traumatic high energy mechanism when wrist is extended and ulnarly deviated. 
  
• Can lead to either Perilunate dislocation where lunate stays in position and carpus dislocates or Lunate dislocates by being forced volar or dorsal while carpus remains aligned
  
• Can see median nerve symptoms in ~25% of patients – most common with lunate dislocation into carpal tunnel.
  

Treatment:
o   Require emergent closed reduction and splinting into sugar tong splint. 

• Place hand in finger traps at 90 degrees of elbow flexion with 5-10lbs of traction. 
  
• Wrist traction with one hand and recreate deformity (volar or dorsal dislocation) and pressing with thumb of the non-extending hand onto dislocated carpal bone attempting to press it back into place. 
  
• Reduces median nerve injury and minimizes cartilage damage. 

o   Require open reduction, ligament repair, fixation and possible carpal tunnel release. 

• Even with reduction and operative treatment may still not return to full function with reduced grip strength and stiffness. 
  

Pearls:

• Must obtain a lateral to evaluate for fracture as AP may not reveal obvious carpal misalignment. 
  
• Diagnosis missed 25% of the time. 
  
• Either lunate stays in position and carpus dislocates or carpus stays in position and lunate dislocates. 
  
• Emergent reduction/splinting to reduce incidence of median nerve injury and cartilage damage. 
  

HPI: Adult male presents after being involved in a motor vehicle collision with right wrist pain and obvious distal deformity.

PE: Obvious deformity of the right wrist. No abrasions or ecchymosis. Full thumb abduction, able to flex at DIP and PIP joint of all 5 fingers, full abduction of all 4 palmar fingers, 5/5 strength to finger grip. Slightly limited range of motion to flexion or extension wrist secondary to pain. Significant pain with pronation and supination. Normal sensation to pinprick and two point discrimination of all five fingers. 2+ radial pulse with normal cap refill. 

Imaging:

How to Diagnosis:

Radial shaft fracture and concurrent distal radioulnar joint. Most commonly seen in fractures of the distal 1/3 of the radius. Termed a Galeazzi fracture. Typically occurs secondary to direct wrist trauma (most classically dorsolateral) or with fall onto outstretched hand with forearm in pronation. 

Anatomy:

• Radius and ulnar articulate along the sigmoid notch of the radius. 
  
• Radioulnar ligaments along the volar and dorsal ligaments. 
  
• This  relationship confers the stability of supination and pronation.

HPI:  Middle age male who presents after falling at work. His medial forearm stroke a metal bucket just distal to his elbow and resulted in a large laceration.

PE: Patient is unable to flex at the DIP of digit 4 and 5. He is unable to cross the second and third fingers or adduct his fingers. He has decreased sensation over the medial aspect of the 4th and 5th digit.  Suspected ulnar nerve laceration. 

Innervation:
-   Motor:

• Flexor carpi ulnaris and Flexor digitorum profundus for the 4th and 5th digits.
• Adductor pollicis and deep head of flexor pollicis brevis
• Interossei and 3rd and 4th lumbricals. 
• Abductor digiti minimi, opponens digiti minimi, flexor digiti minimi. 
  

-    Sensory:

•  Dorsal and palmar cutaneous branches as well as Superficial terminal branches. 
  

Clinical conditions:

•  Distal humerus fracture
  
•  External compression at the medial epicondyle
  
•  Prolonged elbow flexion. 
  
•  Medial epicondylitis (Golfer’s elbow)
  
•  Compression in Guyon’s canal (spares 4th and 5th digit flexion)
  
•  Propulsion of a wheelchair
  
•  Fractures of the hook of the hamate
  

Treatment: Forearm exploration with transected nerve repair.

Pearls:

•  Evaluate flexion at the DIP of the 4th and 5th digits. 
  
•  Inablity to adduct the fingers. Crossing the 2nd and 3rd digit is maximum adduction. If unable to do this secondary to pain, can adduct 2nd and 3rd digit in “scissoring” motion against examiners fingers between the medial aspect of 2nd digit and lateral aspect of 3rd digit.  
  
•  Decreased sensation at the lateral 4th and entire 5th digit. 
  
•  Compression in Guyon’s canal will exhibit decreased sensation and inability to adduct the fingers. Flexion of 4th and 5th digit is spared.