Background Osteoarthritis (OA) of the knee, whether primary or post-traumatic, does not always involve all three compartments (tibiofemoral medial and lateral and the patellofemoral ones). Bicompartmental knee arthroplasty (BKA) was proposed as a good alternative to total knee arthroplasty when two of the three knee compartments were affected. Materials and methods We performed a retrospective comparative study collecting all BKAs performed between March 2010 and January 2016. During this period, we treated 27 patients with BKA for medial or lateral and patellofemoral OA. Seven of them were lost to follow-up and were not included in the study. Group A (BKA group) was compared to a homogeneous group of 20 patients who underwent TKA during the same period (group B). Results Patients treated with TKA were younger than those treated with BKA (mean age 65 vs. 67.2; p  = 0.2149). BKA resulted in longer mean operating time (87 vs. 82.4 min; p  = 0.2983), less blood loss (413 vs. 458 ml; p  = 0.0052) but higher blood transfusion rate (12 vs. 10%). Medium follow-up was 34 months for BKA group and 38 months for TKA group. No statistically significant differences were found in KSS score between the two groups (KSS score 92.3 for BKA, 94.5 for TKA; p  = 0.5221; KSS function was 87.2 for BKA and 89.2 for TKA; p  = 0.4985). Conclusion The most important finding of the present study was that although BKA seemed to be theoretically more favorable in terms of functional recovery and blood loss, patients of group A had lower KSS score and higher transfusion rate than those of group B. Our data confirm that BKA could be proposed as an alternative to TKA, especially in young and high-demanding patients.