Isokinetic profile in female athletes with and without patellofemoral pain syndrome after anterior cruciate ligament reconstruction

Anterior Cruciate Ligament (ACL) injury is one of the most frequent injury type in individuals who participate in pivoting sports, with an annual incidence of more than 200,000 cases according to the American Academy of Orthopaedic Surgeons (2007).This has motivated numerous studies on risk factors and prevention strategies (see Griffin et al., 2000 for review), as well as on ACL reconstructiontechnics (see Spindler et al., 2004 as an example). The most prevalent complications after ACL reconstruction are quadriceps weakness, flexion contracture, and patellofemoral pain (Sachs et al., 1989).Patellofemoral Pain Syndrome (PFPS) is characterised by pain around the patella mainly at activities that load the patellofemoral joint like bending knees, walking stairs or kneeling. The origin of the complaints is not fully understood although weakness and/or tightness of the extensor muscles, changes in medial and lateral quadriceps muscle reflex time, patellar laxity and increased navicular drop are suggested to be associated with PFPS (Boling et al., 2009; Witvrouw et al., 2000). This study therefore aimed at comparing the isokinetic profile in female athletes with and without PFPSto gain further understanding in characteristics and prognosis of PFPS after ACL reconstruction.