Sharp score of joint involvement by rheumatoid arthritis on plain radiographs

The original Sharp score included erosion score and joint space narrowing score for each evaluated joint. The number of evaluated joints was later decreased to reflect more accurately the extent of abnormalities and to shorten the amount of time required to read the films.
This modification considers 17 areas for erosion for each hand:

  • five proximal interphalageal joints (PIP)
  • five metacarpophalangeal (MCP)
  • base of the first metacarpal bone (MCB)
  • multangular bone
  • navicular bone
  • lunate bone
  • triquetrum + pisiform bone
  • radius
  • ulnar bone

and 18 areas for joint space narrowing for each hand:

  • five proximal interphalangeal joints (PIP)
  • five metacerpophalangela joints (MCP)
  • 3rd to 5th carpometacarpal joint (CMC)
  • multangular-navicular joint
  • lunage-triquetrum joint
  • capitate-navicular-lunate joint
  • radiocarpal joint
  • radioulnar joint

A) Erosion score

from 0 to 5 is given according to number of erosion in each joint with 5 representing total destrution. In the 1985 modification, it ranges from 0 to 170.

Score Description
0 No erosion
1 1 erosion
2 2 erosions
3 3 erosions
4 4 erosions
5 total destruction

B) Joint space narrowing

from 0 to 4. In the 1985 modification, it ranges from 0 to 144.

Score Description
0 Normal
1 Focal narrowing
2 Reduction of <50% of joint space
3 Reduction of >50% of joint space
4 Ankylosis


1. Sharp JT, Lidsky MD, Collins LC, Moreland J. Methods of scoring the progression of radiologic changes in rheumatoid arthritis. Correlation of radiologic, clinical and laboratory abnormalities. Arthritis Rheum. 1971 Dec;14(6):706–20.
2. Sharp JT, Young DY, Bluhm GB, Brook A, Brower AC, Corbett M, et al. How many joints in the hands and wrists should be included in a score of radiologic abnormalities used to assess rheumatoid arthritis? Arthritis Rheum. 1985 Dec;28(12):1326–35.

3. Boini S, Guillemin F. Radiographic scoring methods as outcome measures in rheumatoid arthritis: properties and advantages. Ann Rheum Dis. 2001 Sep 1;60(9):817–27.