Objective <p>Multiligament knee injuries (MLKIs) often involve the medial patellofemoral ligament (MPFL), but evidence regarding the effects of MPFL tears on patellar stability and knee function following MLKIs is still lacking. This study included patients with MLKIs and aimed (1) to investigate the incidence of MPFL tears, (2) to evaluate whether untreated MPFL tears lead to patellar instability, and (3) to compare the clinical and functional outcomes between patients with and without MPFL tears.</p> Methods <p>The clinical data of 45 patients were analysed retrospectively from November 2015 to September 2022. The MLKIs and MPFL injuries were evaluated via physical examination and magnetic resonance imaging. All patients underwent single-stage surgery, in which the ACL and PCL were reconstructed via arthroscopy, and the MPFL tears were not treated. The patients were divided into an MPFL tear group (<i>n</i> = 23) and an MPFL intact group (<i>n</i> = 22). The symptom of patellar instability were evaluated via the Kujala Knee Questionnaire. Knee function was evaluated via the Lysholm, Tegner, and International Knee Documentation Committee score.</p> Results <p>Twenty-three patients (51.1%) developed MPFL tears in MLKIs. The mean follow-up time was 62.2 (18–100) months. During the follow-up period, no patients experienced symptoms of patellofemoral instability or patellar dislocation. There was no significant difference in the Kujala Knee Questionnaire score between the two groups (95.9 ± 3.4 vs. 94.6 ± 9.5, <i>P</i> = 0.663). The knee function score did not differ between MLKI patients with and without MPFL tears.</p> Conclusions <p>MPFL tears occur in 51.1% of patients with MLKIs but do not result in patellar instability or affect knee function.</p>