NJR data in the UK shows an increase in the use of MIS in unicondylar knee replacements from 37% in 2004 to 48% in 2011.
Indications for a partial (unicompartmental) knee replacement include isolated OA to only one compartment, no fixed varus deformity over 10 degrees or fixed valgus deformity over 5 degrees .
Contraindications include inflammatory arthropathy and ACL deficiency as well as previous meniscectomy in the contralateral compartment .
Hence why only 6% of patients meet these criteria [125].