Objective To compare the patient-reported outcomes regarding function, joint amnesia, and the quality of life after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). Methods The clinical data of patients who received UKA or TKA between September 2017 and June 2018 were retrospectively analyzed. After propensity score matching, 40 patients (40 knees) each in TKA group and UKA group were finally included in the study. There was no significant difference between the two groups in gender, age, body mass index, surgical side, preoperative knee range of motion, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score, clinical and function scores of knee society score (KSS) (P>0.05). At 2 years after operation, WOMAC score, KSS clinical and function scores were performed on the two groups of patients, and compared with preoperative ones; knee injury and osteoarthritis outcome score-physical function short form (KOOS-PS), short-form 36 health survey scale (SF-36 scale), and forgotten joint score (FJS) were also performed. Results At 2 years after operation, the total score of WOMAC, the clinical and function scores of KSS in the two groups significantly improved when compared with preoperative ones (P<0.05), but there was no significant difference in the total score of WOMAC, the individual score of WOMAC, the clinical and function scores of KSS between the two groups (P>0.05). The total KOOS-PS score in the UKA group was significantly lower than that in the TKA group (t=4.243, P=0.000), and the scores of writhing/knee rotation, kneeling, and squatting in the UKA group were significantly lower than those in the TKA group (P<0.05). The total FJS score in the UKA group was significantly higher than that in the TKA group (t=−6.334, P=0.000). In the UKA group, the scores of 7 items were significantly lower than those of the TKA group (P<0.05) including when walking over 15 minutes, when climbing stairs, when walking on uneven ground, when standing for long periods, when doing housework or gardening, when taking a walk or hiking, and when doing your favorite sport. The SF-36 scales of physiological function, energy, social function, emotional function, and mental health in the UKA group were significantly higher than those in the TKA group (P<0.05). Conclusion Compared with TKA, patients treated with UKA may have better knee function recovery, joint amnesia, and higher quality of life.