Reconstruction of medial patellofemoral ligament for chronic patellar instability.

[trochlear dysplasia]

Disruption of the capsule , medial patellar retinaculum , and /or vastus medialis obliqus has been associated with recurrent patellar instability . Biomechanical studies have shown that the medial patellofemoral ligament (MPFL ) is the main restraint against lateral patella displacement and reconstruction of the MPFL has become an accepted surgical technique to restore patellofemoral stability in patients having recurrent patellar dislocation . We report a prospective series of patients of chronic patellar instability treated by reconstruction of medial patellofemoral ligament .Twelve patients (15 knees ) with recurrent dislocation of patella , were operated between January 2006 and December 2008 . All patients had generalised ligament laxity with none had severe grade of patella alta or trochlear dysplasia . The MPFL was reconstructed with doubled semitendinosus tendon . Patients were followed up with subjective criteria , patellar inclination angle , and Kujala score .The mean duration of followup after the operative procedures was an average of 42 months (range 24 -60 months ) 10 knees showed excellent results , 3 knees gave good results , and 2 knees had a fair result . The average patellar inclination angle decreased from 34 .3 ° to 18 .6 °. The average preoperative Kujala functional score was 44 .8 and the average postoperative score was 91 .9 .MPFL reconstruction using the semitendinosus tendon gives good results in patients with chronic patellar instability without predisposing factors like severe patella alta and high -grade trochlear dysplasia , and for revision cases .