Chapter 70 - Functional Anatomy And Principles Of Upper Extremity Surgery Flashcards
The CMC joints
- The mobility of the CMC joints of the index through small fingers increases toward the ulnar aspect of the hand
- Angulated fractures are better tolerated in the ulnar digits because of compensatory motion
The MCP joints
- Have little tolerance for stiffness coz arc of motion of fingers starts at MCP joints
The PIP and DIP joints
- Stiffness is better tolerated
- Particularly DIP joint, STABILITY is more important than MOBILITY
- Rotational and angular deformity are not tolerated coz the may lead to scissoring of the fingers
The forces acting on hand joints
- Includes:
1- static constraints (collateral ligaments, joint capsules, volar plate)
2- tendons (create dynamic compression through movement)
Swan-neck deformity
- Volar plate disruption during dorsal dislocation of PIP
- Lat bands may subluxate dorsally over time
- Hyperextension of PIP
- Flexion of DIP
Boutonnière deformity
- Disruption of central slip of dorsal middle phalanx and triangular ligament
- lat bands subluxate volarly
- Flexion of PIP
- Hyperextension of DIP
Wrist
- Normal flex/ext => 90/70 deg
- Arc => 80 deg
Distal Radioulnar Joint
- Ulna has no direct contact with carpal bones
- Ulna connected to radius by triangular fibrocartilage complex
The Radiocarpal joint
- 80% of the forces through the arm are dispersed by the carpal articulation with radius
- Tough, strong volar capsular ligament
- Less stout dorsal capaular ligament
Dorsal Intercalated Segment Instability
- Dorsal tilt occurs when the scapholunate ligament is torn coz the scaphoid flexes and the lunate must extend with the triquetrium
Volar Intercalated Segment Instability
- Occurs when the lunotriquetrial ligament is disrupted, leaving the scapholunate ligament intact, resulting in flexion of lunate with scaphoid
Acute injuries
- Life over limb
- Attempting to “tie off” a bleeding vessel is not recommended
- Elevation and direct pressure is sufficient to stop bleeding
Injuries that require urgent operative intervention
- Limb-threatening ischemia
- Most open fractures
- Pressure injection injuries
- Active bleeding in the setting of coagulopathy
For amputated digits
- Hypothermia (wrapped in moist gauze inside plastic bag placed on ice) reduce the metabolic by-product that damage the tissue
Autonomous sensory zone of Radial, Median and Ulnar nerves
- Radial n. => first dorsal web space
- Median n. => volar aspect of index fingertip
- Ulnar n. => volar tip of the small fingertip
Intrinsic positioning of the hand
- Wrist in slight extension
- MCP in near full flexion
- IP in full extension
Reconstructive Principles in Upper Limb
1- Restore circulation 2- Obtain soft tissue coverage 3- Align and stabilize bony anatomy 4- Restore nerve function 5- Mobilize joints 6- Restore tendon function
Use of antibiotics
- Indicated in procedures involving implants or bony work and those lasting > 2 hr
- Abc redosed during surgery depending on the half life properties of the drug
Tourniquet
- 100 mmHg above the systolic BP is sufficient
- Tourniquet time up to 90 min
- Anything over 90-120 min, increases the risk of reperfusion injury
- Arm tor. => elbow, forearm and wrist
- Forearm tor. => hand and digits
Incisions in hand
- Should not cross the flexion crease
- Longitudinal incision for dorsum of hand (coz have thinner and more mobile skin)
- Zigzag incision for volar aspect of palm and fingers
Bruner incision
- Diagonal incisions between flexion creases that serve to create a series of short broad-based flaps
Closure of hand incisions
- Single layer interrupted nylon suture
- If a laceration crosses skin crease, a Z-plasty is considered
Dressing of wounds
- Non-occlusive yet adherent (petroleum impregnated gauze)
- Dry gauze or fluffy
- Circumferential dressing applied loosely
- Splint immobilisation
- Elevation of the hand
