Mid-term Study On The Effect Of Arthroscopic Discoid Lateral Meniscioplasty On Patellfemoral Joint

Purpose To compare the magnetic resonance imaging findings of the patellofemoral joint in the standing position before and after arthroscopic discoid lateral meniscus plasty,and to investigate the mid-term effect of the surgery on the biomechanical patellofemoral joint.Methods From September 2010 to March 2012,a series of 25 patients diagnosed with discoid lateral meniscus injury and underwent arthroscopic meniscus plasty in our hospital participated in this prospective study.All patients underwent clinical evaluation before operation and at the last follow-up,and imaging evaluation was performed by upright magnetic resonance imaging before operation,one month after operation and at the last follow-up.Clinical evaluation included Lysholm knee joint score,Kujala patellofemoral joint score,McMurray’s test,patella mobility,patella grinding test,and quadriceps atrophy Imaging evaluation included bisect offset index,patella tilt angle,and cartilage damage.The changes of patellofemoral joint in each follow-up node were compared.Results Lysholm knee joint score,Kujala patellofemoral joint score,McMurray’s sign,and quadriceps atrophy at the last follow-up were significantly improved compared with those before surgery,with statistically significant differences(P<0.05).At the last follow-up,there was no statistical difference in patella mobility and patella grinding test compared with preoperative levels.At each follow-up node,bisect offset index and patella tilt angle showed a dynamic change of rising and then falling(P<0.05).At one month after the operation,the bisect offset index and patella tilt angle increased significantly compared with the level of the pre-operation and the last follow-up(P<0.05),but the two items had no difference between the pre-operation and the last follow-up.Cartilage damage worsens over time(P<0.05),and the two were positively correlated(Spearman=0.368).In the last follow-up,the degree of cartilage damage was significantly increased compared with that before operation(P<0.05),while there was no significant difference between the one-month postoperative injury and the pre-operative and last follow-up.Conclusions The effect of arthroscopic discoid lateral meniscus plasty on the patellofemoral joint was dynamic,with the position of the patella deviating in the early stages but recovering in the mid-term,especially when the knee was in a biomechanical standing position.In addition,the patellofemoral joint cartilage may undergo accelerated degeneration after the operation,but the mid-term effect of the operation is positive and the patellofemoral joint function is satisfactory.