Objective <p>This study endeavors to systematically investigate factors influencing knee joint stability following anterior cruciate ligament reconstruction (ACLR) using magnetic resonance imaging (MRI), with the goal of providing quantitative imaging evidence for determining clinical rehabilitation timelines and objectively evaluating treatment efficacy.</p> Method <p>A total of 31 patients undergoing ACLR were retrospectively evaluated with MRI scans at 1, 4, and 12 months postoperatively. Parameters included graft length, tibial anteroposterior displacement, tunnel position, and angulation metrics JGS, JGC, angle α, angle β, angle θ)).Clinical outcomes were assessed using the Lysholm score. Longitudinal differences in stability parameters were analyzed by repeated-measures ANOVA (<i>p</i> &lt; 0.05), with ROC curves evaluating diagnostic sensitivity.</p> Result <p>Among 31 patients, 28 achieved satisfactory graft healing, while three required revision reconstruction. At 4 months postoperatively, significant reductions in joint effusion volume and soft tissue swelling were observed. Knee joint stability at 12 months was significantly superior to values at both 1- and 4-month intervals (<i>p</i> &lt; 0.05). Tibial range of motion and β-angle were significantly associated with joint stability, with AUC values of 0.64 and 0.62, respectively.</p> Conclusion <p>Multiparametric MRI objectively evaluates post-ACLR intra-articular healing and joint stability, delivering critical imaging evidence to guide evidence-based rehabilitation planning.</p> Clinical trial number <p>Not applicable.</p>