What is the most dislocated joint?
Glenohumeral Joint
What is the most common direction for a GH dislocation?
Anterior
What is the etiology of an anterior GH dislocation?
- Mechanism: External rotation and abduction with FOOSH (fall on an outstretched hand)
- Anterior-inferior direction of humeral head
What is the etiology of a posterior GH dislocation?
- Less common 2-4%
- Mechanism: 90 degrees of flexion with a FOOSH
What is the third etiology for GH dislocations? (hint: not anterior or posterior)
Recurrent
What are the structures involved in a dislocation?
- Stretch or tear of the capsule or ligaments
- Other possible damage: an anterior labrum tear (aka a bankart lesion) or a SLAP tear
What types of impingement are likely to result from dislocations? (hint: hypo or hyper)
Hypermobile
In a bankart lesion the humeral head dislocates in what direction?
Anterior - Inferior (chip off the front)
A SLAP tear is located where?
The superior portion of the labrum below the biceps tendon
Fibrocartilage is described as having a _____ outer portion and a _____ inner portion.
- Thick outer, thin inner
- Thicker and concave compared to articular cartilage
Fibrocartilage helps to do what for the joint surface
Widen and deepen it
Fibrocartilage is located where?
- The shoulder and hip
- SC, tibiofemoral, AC, ulnotriquetral, intervertebral, and pubic symphysis joints
What are the structures of fibrocartilage?
- Fibro and chondrocytes
- Collagen
What is the function of the outer collagen (primarily type 1 collagen)?
- Resists tension for stabilization
- Majority type for all fibrocartilage, including with glenoid labrum
What is the function of the inner collagen (secondarily and less type 2, 3, and 4 collagen)?
Resists compression for shock absorption
Which part of the fibrocartilage (outer or inner) is made up of vascular and neural tissue?
The outer
What are the neural attributes of the outer fibrocartilage used for?
- Proprioception
- Kinesthesia like ligament
- Annulus for stabilization
If the outer part of the fibrocartilage is neural and vascular that makes the inner?
Hypo- or avascular, aneural, and alymphatic
What is the etiology of fibrocartilage injuries?
- Acute tears with RTC tears and dislocations
- Gradual tears from repetitive and or extreme motions and compressive stresses. often with sports and impingement
What does healing looking like for fibrocartilage?
- Better at the periphery due to greater vascularity
- Tensile strength initially improves at 3-5 weeks
- Even greater tensile strength when dense fibrous tissue fills in at 8-12 weeks
What is your MET focus for fibrocartilage?
- Tissue integrity/ proliferation with vascularity issues
- Stabilization due to stabilizing roles of fibrocartilage
What other damage or complications can be found with damage to the fibrocartilage?
- Fractures (aka hill sachs lesion - compression fracture of the humeral head)
- RC tear
- Neurovascular structures
Dislocations are like impingements plus …
- Trauma in characteristic position
- Acute presentation
Dislocations have signs like impingements plus what other things?
- ROM: limited and painful in most directions
- Resisted and MMT: weak and painful in most directions
- Stress tests: likely (+) depending on structures involved
