Proximal Humerus Fx Flashcards
Retroversion of the Humerus
35-40 degrees relative to teh epicondylar axis
Four Osseous Segments
(1) humeral head
(2) lesser tuberosity
(3) greater tuberosity
(4) humeral shaft
Deforming Muscular Forces on Prox Hum
(1) supraspinatus and external rotators displace the greater tuberosity superior and posterior
(2) subscap displaces the lesser tuberosity medially
(3) pectoralis major displaces the humeral shaft medially
(4) deltoid abducts the prox fragment
Blood Supply
Major: ant and post humeral circumflex arteries
Arcuate (cont of ascending of ant circ) - enters the bicipital groove and supplies most of the humeral head
- Fx of anatomic neck are uncommon
- poorer prog bc of vascular supply
Neuro
Axillary nerve course just ant-inf to glenohumeral joint
- Traversing the quadrangular space
- Traction injury (rigid fixation at post cord and deltoid as well as its prox to the inferior capsule
- susceptible with ant dislocation/ant - fx dislocation
Exam
NV - sensation on the lateral aspect of the prox arm overlying the deltoid
Rads
AP and Lateral view in the scapular plane and axillary
Axillary - eval of glenoid articular frx and reduction of the GH articulation
Velpeau axillary : if standard ax cannot be obtained.
-Can leave pt in sling and lean obliquely backward 45 degrees over the cassette. Beam is directed caudally orthogonal to the cassette (ax with magnification).
Can also get CT
Neer Classification
Uses 4 Osseous Segments:
>One-part fx: no displaced fragments regardless of # of fx lines
>Two-part fx: Anatomic Neck/Surgical Neck/Greater tub/Lesser Tub
>Three-part fx: surgical neck with greater or lesser tub
>four part
>fx dislocation
>articular surgace fx
Treatment Minimally Displaced (1 part)
Sling, early motion, early f/u with rads
Treatment 2 part fx
Anatomic neck fx:
-rare ORIF (younger) or prosthetic (older) - high incidence of osteonecrosis
Surgical Neck fx:
- Non-op: if stable (move as unit) in lower demand individuals, severly debilitated pts, and those who cannot tolerate surg
- CRPP: young with good-quality bone (problems: nerve injury, pin loosening, pin migration and inability to move the arm).
- ORIF: most displaced plate or intramedullary device. Plate use locked screw for metaphyseal component
- Prosthetic replacement: considered with extreme osteopenia (Hemi, total or reverse)
Greater Tub
- ORIF +/- rotator cuff repair if displaced >5-10mm (5mm for superior translation); otherwise nonunion or subacromial impingement.
- GT fx ass with ant dislocation may reduce on reduction of the GH joint and be treated non-op
- Lesser Tub: may be treated closed unless displaced frag block internal roation, r/o post dislocation
3 part fx
Usually unstable, displaced fx require operative tx, except in severely debilitated pts or those who cannot tolerate surg
- Younger should have an attempt at ORIF- preservation of vascular supply is important
- Prosthetic is older is acceptable
Four Part Fx
Incidence of osteonecrosis 4%-35%
- ORIF attemted in pts with good quality bone if humeral head is w/n glenoid fossa
- Prosthetic in elderly
- Four-part valgus impacted proximal humerus fx represent variants that are ass with lower rate of osteonecrosis and have excellent results with ORIF
2 part fx dislocations
Tx closed after shoulder reduction unles the fx frag remain displaced.
3 and 4 part fx dislocation
ORIF in younger individuals and prosthetic replacement in the elderly depending on length of dislocation.
- Brachial plexus and axillary artery are in proximity to the humeral head frag with ant fx-dislocations
- Recurrent dislocation is rare following fx union
- Prosthetic replacement for anatomic neck fx-dislocation is recommended bc of high incidence of osteonecrosis
- These injuries may be ass with increased of myositis ossificans with repeated attempts at CR
Articular Surface Fx
Hill-Sachs, reverse Hill-Sachs
- Often associated with post dislocations
- Pts with >40% of humeral head involvement may require prosthetic replacement; ORIF should initially be considered in pts <40 of age, if possible.
Ant Approach to the Humeral Shaft
Landmarks and Internervous Plane
Palpate Coracoid process and long hed of the biceps brachii as it crsses the shoulder and runs down the arm.
Neuro:
(1) Prox - b/t deltoid (axillary) and pectoralis major (med/lat pec)
(2) Distally - b/t medial fibers of the brachialis muscle (MC nerve) medially and the lateral fibers of the brachialis muscle (radial) laterally.
Prox and Distal Humeral Shaft Superficial Dissection
PROX: ID deltopectoral groove (cephalic vein/triangle of fat) and separate - retracted cephalic either medially or laterally, develop plane down to insertion of deltiod at tuberosity.
DISTAL: ID muscular interval b/t biceps brachii (retract medially) and the brachialis - will uncover brachialis which cloacks the humeral shaft
Prox and Distal Humeral Shaft Deep Dissection
PROX: Incse the periosteum longitudinally just lateral to the insertion of the tendon of the pec major. Cont prox (stay lat to tendon of long head of biceps).
- Ant circumflex humeral artery crosses the field of dissection in a medial to lateral direction and must be ligated
- May need to resect part of pec to get better exposure - stay subperiosteal to avoid damage to radial nerve (spiral groove of humerus and crsses the back fo the middle 1/3 of the bone in a medial to lat direction).
- Head/anatomic neck exposure - subscapularis (triad of vessels run along lower border-coagulate)
DISTAL: split fibers of the brachialis longitudinally along its midline to expose the periosteum on the anterior surface.
DANGERS!!
-Radial Nerve: (1) spiral groove on the back of the middle 1/3 of the humerus (2) ant compartment of the distal 1/3 of the arm. Lies between brachioradialis and brachialis muscle. Split brachialis at midline and lateral portion will protect radial nerve.
Axillary nerve: underside the deltoid muslce - compression injury causded by vigorous retraction
Anterior Circumflex humeral vessels: cross operative field in the interval bt the pec major and deltoid muscles in the upper 1/3 of the arm.
