BACKGROUND: Some patients submitted to isolated ACL reconstruction may have symptomatic postoperative rotational instability. The objective of this study was to evaluate a population with mild rotatory instability after ACL reconstruction, which was submitted to an isolated extra-articular procedure. METHODS: Patients submitted to an isolated extra-articular procedure after ACL reconstruction were retrospectively evaluated. Only patients presenting anterior knee instability of less than 5 mm, pivot-shift of a maximum of 1+, and ACL graft intact were included. Demographic data, physical examination and subjective functional scales were evaluated. RESULTS: Twenty patients were included. The mean age was 27.0 ± 7.3 years. The follow up time after the extra-articular procedure was 27.5 ± 6.2 months. The KT-1000 decreased from 3.0 mm ± 0.7 mm to 2 mm ± 0.4 mm (P = 0.00016). The pivot-shift improved from 100% of grade 1 positivity to 30% (6/20 patients) of grade 1 positivity (P <
0.0001). The IKDC showed no difference (74.4 ± 11.8 vs. 87.6 ± 5.8
P = 0.087), but the percentage of patients who passed the PASS IKDC cut-off value increased from 45% (9/20) to 95% (19/20) (P = 0.0012). The Lysholm increased from 81.1 ± 7.3 to 91.2 ± 5.7 (P = 0.0001). CONCLUSIONS: Patients submitted to an isolated extra-articular procedure due to residual instability after ACL reconstruction showed improvement in physical examination (KT-1000 and pivot-shift) and subjective functional scales. This procedure can be considered for a specific population with minor instabilities and intact ACL graft, avoiding a complete ACL revision.