Background: Anterior knee pain (AKP) is a frequent serious clinical problem after anterior cruciate ligament (ACL) reconstruction, regardless of the graft material used. The author conducted prospective studies of the correlation between AKP and disturbed geometry of patello-femoral joint observed in magnetic resonance imaging (MRI), in patients with injured ACL reconstructed with the use of hamstrings.
Material and methods: The study included 60 patients (34 males and 26 females), at the mean age of 31, who underwent ACL reconstruction with flexors. Only patients without clinical AKP symptoms or AKP factors after reconstruction were included in the study. Before surgery, in all patients MRI was performed in order to evaluate the patellar height, excessive patellar pressure (EPP) and patellar lateralization (PL). In the postoperative course, AKP and its correlation with the ratios mentioned above were observed.
Results: In the group of patients included in the study, pathological patellar height was not observed, EPP was diagnosed in 15%, PL in 13.3% and EPP and PL jointly in 11.9% of the patients. AKP was observed in 8 out of 9 patients with abnormal lateral pressure, 7 patients with EPP and 7 patients with concomitant excessive lateral pressure and PL. The first symptoms of AKP appeared between the seventh and twelfth week after surgery and increased after 12 weeks.
Conclusions: The occurrence of excessive lateral pressure syndrom (EPP) and PL confirmed in MRI was very strongly correlated (89% and 100%, respectively) with the occurrence of AKP after ACL reconstruction. The evaluation of the patellofemoral joint geometry, taking into account the EPP and PL ratios in pre-operative magnetic resonance image (MRI) in patients with injured anterior cruciate ligament, may allow us to establish the AKP risk group and administer suitable preventive treatment (prophylaxis).