The purpose of this prospective study was to determine whether or not abrasion arthroplasty promotes cartilage regeneration in osteoarthritic (OA) knees with eburnation. Patients with OA knees were divided into a group of 51 knees treated by osteotomy with abrasion arthroplasty (Group A) and another group of 37 knees treated by osteotomy alone (Group B). Regeneration of cartilage was compared between the groups both arthroscopically and histologically. The Outerbridge classification was used for arthroscopic grading with Grade 0 being normal and Grade IV representing eburnation. On arthroscopic examination, around 12 months after surgery, Group A showed a significantly higher incidence of Grade II repair (a smooth articular surface and small fissures) and a lower incidence of Grade IV repair than Group B on both the femoral (P < .001) and tibial (P < .01) joint surfaces. Age was the only factor influencing the grade of tibial cartilage in Group A. Histological examination showed that 64% of the regenerated tissue studied consisted of fibro-cartilage at around 12 months after surgery. There was no difference in the clinical outcome at 2 to 9 years postoperatively between Groups A and B.