Neer's 3 Stages of Impingement Syndrome

From http://www.aafp.org/afp/980215ap/fongemie.html,

Several classification systems are used with the impingement syndrome.

Neer divided impingement syndrome into 3 stages:

Stage 1

• Involves oedema and/or haemorrhage
• Generally occurs in patients less than 25 years of age
• Frequently associated with an overuse injury
• Generally reversible
• Pain only after activity
  

Stage 2

• Tends to occur in patients 25 to 40 years of age
• Evident pathological changes showing fibrosis and irreversible tendon changes
• Pain at beginning only, then after activity
  

Stage 3

• Generally occurs in patients over 50 years of age
• Frequently involves a tendon rupture or tear
• Largely a process of attrition (erosion due to friction) and the culmination of chronic fibrosis and tendinosis
• Pain during and after activity