Table 1 Charnley classification including modification of group B

A

Single-joint arthropathy and no significant medical comorbidity

B

One other joint in need of an arthroplasty, or an unsuccessful or failing arthroplasty in another joint

B1

Contralateral hip in need of arthroplasty, but untreated

B2

Contralateral hip has been successfully treated with an arthroplasty

C

Multiple joints in need of arthroplasty, multiple failing arthroplasties or significant medical or psychological impairment