Kienbock’s
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- AVN of lunate
- 2 main Theories:
- Mechanical - Negative ulnar variance ➔ more load to lunate (this is uncertain as studies show many patients with Kienbock have neutral or positive UV
- Blood supply to lunate (YIX pattern; I pattern high risk). I pattern is the only one with a single vessel.
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- Patient - Same as risk factors for AVN in general
- ‼️ Risk factors/ Causes of AVN? (Hip, Kienbock)
- Most common causes up to 90% reported - are associated with alchohol and steroids
- Idiopathic
- Secondary -
- intravascular factors -
- Systemic disease
- SLE causing vasculitis and venous outflow issues ➔ increased intraosseous pressure
- Sicke cell anemia ➔ abnormal shaped RBC obstruct blood flow
- Radiation ➔ vasculitis
- Hyperlipidmia, Alchohol ➔ theorized to increase lipid levels
- Caisson's decompression disease (release of nitrogen gas bubbles into body)
- Extra-vascular causes -
- INTRAOSSEOUS
- Steroids leading to fat hypertrophy and increased intraooseous pressure
- EXTRAOSSEOUS
- Trauma disrupting blood supply - NOF #, talus #
- Tamponade of blood supply - compressive causes
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- Dorsal Radiocarpal arch DRC
- Palmar Intercarpal Arch PIC
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- Dorsal wrist pain
- "Radiological findings do not correlate with clinical findings" severe changes may not have pain.
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- AP - carpal collapse
- Lateral - scaphoid flexion via scapholunate angle > 60 °
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- Youm's Index can be calculated from PA Hand XR
- Carpal height / MC3 height
- Normal is 0.51 to 0.57
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- Lichtman Classifx
- 1 = normal XR (picked up on MRI)
- 2 = Sclerosis only
- 3 = Lunate collapse [All AVN conditions stage 3 is collapse - Steinberg, Cruess]
- 3a = without carpal collapse
- 3b = with
- Carpal collapse (Youm's index < 0.5)
- Fixed Scaphoid flexion (Scapho lunate angle > 60 °) [Signet Ring sign]
- 4 = Pan Arthritis
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- 1 = Non op
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- ULNAR negative - Joint levelling - Radial shortening for ulnar negative variance
- ULNAR positive - Revascularization (4,5 Extensor compartment Artery [ECA] 2,3 Inter-Compartmental Supraretinacular Artery [ICSRA])/ direct vessel implantation
- Core Decompression
- Distal radius metaphyseal core decompression
- Effect if not caused by unloading of the radius surface
- Instead, hypothesis is that osseous procedures close to the lunate generates a regional vascular response around the carpus.
- 3B/ 4: Carpal Collapse - Options = PRC/ STT fusion/ Wrist arthrodesis
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- Many methods.
- Based on the Gelberman method,
- Line perpendicular to longitudinal axis of Radius, cutting through the midpoint between anterior and posterior margins of the ulnar radius.
- Line perpendicular to longitudinal axis of radius and tanget to distal articular surface of ulna
- Compare the 2
Preiser Disease
- RARE, atraumatic
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- Stage 1 = normal XR, MRI signal change
- Stage 2 = Increase density at proximal pole
- Stage 3 = fragmentation of proximal pole
- Stage 4 = OA changes
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- PRC, 4CF