Anatomic single-bundle anterior cruciate ligament reconstruction partially restores tibiofemoral rotational alignment: a reduction of tibial internal rotation toward baseline

INTRODUCTION/OBJECTIVES: Patellofemoral pain (PFP) is frequently reported following anterior cruciate ligament reconstruction (ACLR). The tibiofemoral rotation angle (TFRA) may influence patellofemoral joint biomechanics as it forms part of the knee extensor mechanism. This study aimed to compare TFRA and other related parameters before and after anatomic single-bundle (SB) ACLR, and to evaluate the relationship between post-operative TFRA, PFP, and knee function. METHODS: Sixty-five patients who underwent anatomic SB-ACLR between 2012 and 2023 were retrospectively reviewed. TFRA, tibial tubercle-trochlear groove (TT-TG) distance, trochlear sulcus angle, Insall-Salvati index, and anterior tibial translation (ATT) were measured on pre- and post-operative radiographs and MRI images. Knee function was assessed using the Kujala and International Knee Documentation Committee (IKDC) scores. RESULTS: ACLR changed the median TFRA from 6° (interquartile range [IQR] = 2 to 10) pre-op to 4° (IQR = -2 to 9) (p < 0.05) post-op. Both intra-observer reliability (ICC = 0.95) and interobserver reliability (ICC = 0.96) exhibited good to excellent agreement. Anterior stability improved, with significant reductions in ATT (The median pre- and post-operative ATT was 9.29, IQR 7.68-10.87 and 6.93, IQR 5.36-8.4, respectively, p < 0.001). No significant differences were observed in TT-TG distance, trochlear sulcus angle, or Insall-Salvati index. CONCLUSION: Anatomic single-bundle ACLR improves anterior knee stability and significantly reduces tibiofemoral rotation angle, reflecting partial restoration of abnormal tibial internal rotation toward baseline. However, the magnitude of correction is limited and does not fully normalize rotational alignment, and its clinical impact remains uncertain. LEVEL OF EVIDENCE: Level of evidence 3. Cross-sectional study.