All-Inside and Conventional Techniques in Anterior Cruciate Ligament Reconstruction: A Retrospective Comparison Study

Objective: The aim of the study was to compare postoperative pain, functional recovery, knee stability and complication profiles between the all-inside technique and the conventional full tibial tunnel technique for anterior cruciate ligament (ACL) reconstruction. Methods: This retrospective comparative cohort study included 104 patients who underwent primary ACL reconstruction between 2018 and 2020. Surgical technique allocation was non-randomized. Patients were divided into two groups based on the surgical technique employed; the conventional full tibial tunnel group (n = 58) and all-inside group (n = 46). Hamstring tendon autografts were used in all cases, and the procedures were performed by the same surgical team to ensure consistency. Clinical outcomes were evaluated using the Visual Analog Scale (VAS) for pain, Lysholm knee score and International Knee Documentation Committee (IKDC) score. Knee stability was assessed with the Lachman and pivot-shift test. Additionally, postoperative complications and revision rates were recorded. Results: The study included 104 patients, with 58 treated using the conventional technique and 46 using the all-inside technique. Baseline characteristics, trauma mechanisms, and follow-up duration were comparable between groups (p > 0.05). Four patients in each group underwent revision surgery and excluded from the final analysis. Revision rates were comparable between groups (6.9% vs. 8.6%) and were considered descriptively when interpreting outcomes. The preoperative VAS, Lysholm and IKDC scores were comparable between groups. At 3 months, the all-inside group demonstrated significantly lower VAS pain scores and higher Lysholm and IKDC scores (with moderate-to-large effect sizes) (all p < 0.01). No significant differences were observed at the 12-month or final follow-up. Postoperative knee stability was comparable between groups, whereas anterior knee pain was significantly less frequent in the all-inside group (p < 0.001). Moreover, patients treated with the all-inside technique returned to sports significantly earlier than those treated with the conventional technique (13.25 ± 2.70 vs. 16.40 ± 5.85 months, p < 0.001; Cohen's d = 0.66). However, the proportion of patients who returned to their preinjury sports level was comparable between the two groups (81.0% vs. 83.3%, p = 0.78). Conclusions: The all-inside ACL reconstruction technique was associated with superior early pain relief and short-term functional outcomes compared with the conventional technique, while achieving comparable knee stability and mid-term clinical results. These advantages occur without increasing complications or revision rates. These findings support the all-inside technique as patient-centered, optimizing early recovery without sacrificing mid-term clinical durability. These findings should be interpreted in the context of the non-randomized retrospective study design.