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Glaucoma

Glaucoma

Group of progressive optic neuropathies characterized by structural damage to the optic nerve head and retinal nerve fiber layer, resulting in characteristic visual field loss. Elevated intraocular pressure (IOP) is the major modifiable risk factor, though glaucomatous damage can occur at normal IOP and not all elevated IOP causes damage (ocular hypertension).

Classified by:

  • Primary open-angle glaucoma (POAG): most common type, chronic, open anterior chamber angle, gradual trabecular meshwork outflow resistance increase, insidious asymptomatic progression

  • Primary angle-closure glaucoma (PACG): anatomically narrow angle, iridocorneal angle apposition/closure obstructing aqueous outflow; can present acutely (angle-closure crisis) or chronically

  • Normal-tension glaucoma: glaucomatous damage despite IOP within statistically normal range

  • Secondary glaucoma: due to identifiable cause — neovascular (diabetic retinopathy, CRVO), pseudoexfoliative, pigmentary, uveitic, steroid-induced, traumatic, lens-induced

  • Congenital/developmental glaucoma: rare, due to trabecular meshwork developmental anomaly, presents in infancy (buphthalmos, photophobia, epiphora)

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Continue reading · Surgery

Tibial Plateau Fracture

A tibial plateau fracture involves the articular surface of the proximal tibia and ranges from a simple low energy lateral split to severe bicondylar comminution with metaphyseal dissociation, compartment syndrome and major soft tissue injury.

The treatment objectives are:

  • Restore a stable, congruent knee joint
  • Restore coronal and sagittal alignment
  • Restore condylar width
  • Preserve meniscal tissue
  • Address ligamentous instability where clinically significant
  • Preserve soft tissue biology
  • Permit early knee motion

Perfect reconstruction of every small articular fragment is less important than restoring the major weight bearing surface, mechanical axis and joint stability.

High energy plateau fractures must be viewed as soft tissue injuries with an associated fracture, not simply a radiographic bone problem.

Schatzker classification

Type I

Pure lateral plateau split fracture.

Usually occurs in younger patients with relatively strong cancellous bone.

Type II

Lateral split plus articular depression.

Common pattern, particularly in middle aged or older patients.

Type III

Pure lateral or central articular depression without a major cortical split.

Usually occurs in osteoporotic bone.

Type IV

Medial plateau fracture, either split or split depression.

Typically higher energy and more unstable than lateral plateau injuries.

Associated with greater risk of:

  • Popliteal artery injury
  • Common peroneal nerve injury
  • Ligament disruption
  • Compartment syndrome

Type V

Bicondylar fracture involving both medial and lateral plateaus while metaphyseal continuity with the tibial shaft is preserved.

Type VI

Plateau fracture with complete metaphyseal diaphyseal dissociation.

This is a high energy injury frequently associated with severe soft tissue trauma and compartment syndrome.

Schatzker IV, V and VI patterns should immediately raise the threshold of concern for associated soft tissue, vascular and compartment injury.

AO/OTA classification

Proximal tibial fractures are coded 41.

41A: Extraarticular

The articular surface is intact.

41B: Partial articular

Part of the articular surface is fractured while another part remains connected to the tibial shaft.

Broadly includes:

  • B1 pure split
  • B2 pure depression
  • B3 split depression

41C: Complete articular

The entire articular surface is separated from the tibial shaft.

  • C1 simple articular and simple metaphyseal fracture
  • C2 simple articular fracture with metaphyseal comminution
  • C3 multifragmentary articular fracture

Modern CT based assessment adds important information regarding posteromedial and posterolateral fragments, which are inadequately represented by a purely AP radiographic classification.