We aimed to investigate the technical advantages and clinical outcomes of lateral unicompartmental knee arthroplasty (LUKA) through the medial parapatellar approach. From August 2022 to June 2024, 104 patients who underwent LUKA via the medial parapatellar approach were enrolled. The operation time, hospital stays, surgical complications and follow-up period were collected. Pre- and postoperative Range of movement (ROM), Oxford knee score (OKS) and Hospital for special surgery knee score (HSS) were recorded and further investigated by paired-samples t-test analysis. Primary demographic data of the retrospective case series collected include gender (30 males and 74 females), age (63.1 ± 8.37years, range 49-84years), operation time (86 ± 17min, range 52-135min), hospital stays (4.0 ± 1.1days, range 3-8days) and follow-up period (9.9 ± 5.7months, range 1-23months). There was a significant improvement in ROM (P < 0.001), OKS (P < 0.001) and HSS (P < 0.001) compared to preoperative values. Patient satisfaction at 1-month postoperative follow-up was up to 95%. The incidence of deep venous thrombosis was 16.3%. There was no incidence of postoperative infection. The medial parapatellar approach is a understandable, easy to master and credible surgical approach for LUKA, showing a striking improvement in clinical outcomes without adverse events in the short-term follow-up.