Grades of osteoarthritis by Ahlbäck

Ahlbäck Grade Description
Grade I Joint space narrowing (joint space < 3 mm)
Grade II Joint space obliteration
Grade III Minor bone attrition (0–5 mm)
Grade IV Moderate bone attrition (5–10 mm)
Grade V Severe bone attrition (>10 mm)


1. Petersson I, Boegard T, Saxne T, Silman A, Svensson B. Radiographic osteoarthritis of the knee classified by the Ahlb?ck and Kellgren & Lawrence systems for the tibiofemoral joint in people aged 35-54 years with chronic knee pain. Ann Rheum Dis. 1997 Aug;56(8):493–6.
2. Ahlbäck S. Osteoarthrosis of the knee. A radiographic investigation. Acta Radiol Diagn (Stockh). 1968;Suppl 277:7–72.