• INTRODUCTION
    • One-third of patients with knee osteoarthritis (OA) has involvement of only one compartment, especially the medial one.
  • SOURCES OF DATA
    • We performed a comprehensive search of studies comparing unicompartmental knee arthoplasty (UKA) and total knee arthroplasty (TKA) in the same patient on PubMed, OVID/Medline, Cochrane, CINAHL, Google scholar and Embase databases.
  • AREAS OF AGREEMENT
    • UKA is indicated in knee with medial OA, no flexion deformity, no joint instability and no varus deformity.
  • AREAS OF CONTROVERSY
    • Although high tibial osteotomy, UKA and TKA have been proposed to address medial OA of the knee, the best management is still controversial.
  • GROWING POINTS
    • Studies investigating surgical management of medial OA of the knee are increasingly frequent.
  • AREAS TIMELY FOR DEVELOPING RESEARCH
    • Large, multicentre, powered, randomized trials comparing UKA and TKA are needed to identify the best management for medial OA of the knee. Moreover, new score systems for satisfaction of the patient should be formulated.