All in the wrist
Name all 15 bones that are in the complex wrist joint.
2 forearm bones: Radius ulna
8 carpal bones: SLTPHCTT
5 metacarpals
How far from the tendon edge should sutures be placed for adequate strength?
10mm
Name 5 ways to fix a metacarpal fracture
closed reduction
k wire
mini plate
lag screw
IM screw
<50% involved = trephination with sterile needle +/- cautery
>50% involved=nail plate removal and nail bed repair (Dermabond equivalent to 6-0 suture in RCT)
describe the motions of the thumb
Flexion/extension
adduction/abduction
opposition
How many tendons insert onto the carpal bones?
Zero! The carpal bones only move based on the tendon forces that insert more distally in the hand
How many core strands are needed for flexor tendon repair?
Because active digital motion without
resistance generates 0 to 30 N of force over the
flexor tendons,24 it is generally believed that a
four-strand core suture (with 4-0 or 3-0 nonabsorb-
able suture) is a minimum requirement.
What is the typical screw length for a bicortical screw in the midshaft of the radius?
12-14mm
Describe the recommended excision (NCCN guidelines) for invasive subungual melanoma excision with a depth of 0.7mm.
In the setting of adequate biopsy, melanoma in situ and lesions <0.8mm Breslow depth may be excised via 5mm margins wide local excision rather than digit amputation at the IP joint.
Describe the shape of the joint between the thumb metacarpal and trapezium.
double saddle architecture
Name the three major groups of extrinsic ligaments of the wrist.
palmar ulnocarpal
dorsal radiocarpal
(there are no dorsal ulnocarpal ligaments)
You complete a zone 2 tendon repair and notice that the repair bulk is being blocked by the pulley system. Which pulleys can you vent, and how much?
The longest annular pulley in the fingers (the A2 pulley) can be vented partially with an incision over its distal or proximal sheath no longer than 1.5 to 2 cm; the annular pulley over the middle phalanx (the A4 pulley) can be vented entirely.
According to the 2020 AAOS/ASSH Clinical Practice Guideline, what is the strength of evidence regarding the superiority of one fixation technique over another for unstable distal radius fractures?
The guideline provides strong evidence that there is no difference in radiographic or patient-reported outcomes between fixation techniques (volar locking plate, dorsal plate, external fixation, percutaneous pinning) for complete articular or unstable distal radius fractures beyond 3 months. However, volar locking plating leads to earlier short-term functional improvement (within the first 3 months). The guideline recommends that fixation technique be driven by fracture pattern and patient characteristics rather than a one-size-fits-all approach. Bridge plating may be preferred when there is substantial metaphyseal comminution or radiocarpal fracture-dislocation.
Name three functions of the nail plate.
1. Protect the fingertip.
2. Provide counterpressure for fine sensation.
3. Acts as a built in tool for small tasks.
Describe the tendons and deforming forces on a Bennet fracture.
Adductor pollicis longus--proximal displacement
adductor pollicis--1st metacarpal is adducted and supinated
Describe the 6 components of the TFCC
dorsal and palmar radioulnar ligaments
articular disc
meniscus homologue
ECU subsheath
ulnar collateral ligament
What threshold of partial flexor tendon laceration can be safely managed nonoperatively, and what is the recommended postoperative motion protocol?
Partial flexor tendon lacerations involving up to 60–90% of the cross-sectional area can be safely managed without surgical repair, as biomechanical studies show these can tolerate loads generated by unresisted active finger flexion. Suture repair of partial lacerations is actually associated with decreased tensile strength and impaired tendon gliding. Indications for surgical exploration include triggering, entrapment, or concern for complete injury. All patients should undergo early protected active motion.
Name and describe 4 anatomical structures for the nail.
Nail plate
Hyponychium
Perionychium
Eponychium and Eponychial fold
Germinal Matrix
Sterile Matrix
Describe the 4 types of pinch
1. key pinch
2. chuck pinch (tripod pinch)
3. closed round pinch
4. closed elongated pinch
Describe the two types of TFCC tears and their associated treatments.
type I - traumatic
type II - degenerative (ulnocarpal impaction)
IIA - TFCC thinning
IIB - IIA + lunate and/or ulnar chondromalacia
IIC - IIB + TFCC perforation
IID - IIC + LT ligament disruption
IIE - IID + ulnocarpal and DRUJ arthritis
Type 1=arthoscopy vs open repair and debridement
Type 2=debridement or ulnar shortening osteotomy (ulnar compaction)
You perform a revision amputation of a crushed ring finger DP. The patient returns in 12 weeks after maximizing hand therapy and complains that his ring finger extends when he tries to make a fist. Name the pathology and describe it biomechanically.
Lumbrical plus, FDP retracts and then the lumbrical muscle is pulled taut when FDP fired, this acts on the lateral bands, paradoxically straightening the finger.
High energy trauma fall onto outstretched hand, patient has DRUJ dislocation, interosseous membrane rupture, and radial head fracture. Name the fracture pattern.
Essex Lopresti fracture
Describe the 4 types of mechanoreceptors present in the fingertips. (must name them and describe function of each).
You are skiing down a mountain and fall on your thumb. The paramedic at the resort attempts to reduce your thumb phalangeal-metacarpal joint. You scream and punch them in the face. The thumb remains very sore. Describe the pathology.
Stener lesion--thumb UCL is trapped behind the adductor pollicis and is unable to be reduced closed.