Middle-to long-term outcome after medial patellofemoral ligament reconstruction with Insall’s proximal realignment for patellar instability

Abstract

BackgroundRecently, medial patellofemoral ligament (MPFL) reconstruction has become a common, widely used procedure to treat patellar instability. However, few reports exist on the long-term outcome after MPFL reconstruction. We elucidated the middle- to long-term outcome after MPFL reconstruction with Insall’s proximal realignment. Methods: From 1999 to 2012, 42 knees of 32 patients who underwent MPFL reconstruction with Insall’s proximal realignment were reviewed with a minimum follow-up of five years. Patients who could visit our office and receive some designated examinations were included in this study. The re-dislocation rate and patellar apprehension sign postoperatively were evaluated. The Kujala score and Knee Injury and Osteoarthritis Outcome Score (KOOS) were calculated. We assessed the images using plane x-ray and magnetic resonance imaging (MRI). The tilting angle (TA), congruence angle (CA), and lateral shift ratio (LSR) on the plane x-ray were measured pre- and postoperatively and at final follow-up. Using MRI, osteochondral lesions at the patellofemoral joint were evaluated. ResultsA total of 20 knees of 15 patients (two male, 13 female) who could visit our office were studied. The follow-up rate was 47.6%. The mean age at operation was 19.9 (11–41) years and mean follow-up was 123 (60–215) months. One knee (5.5%) had a history of postoperative subluxation, and five (25%) had a positive apprehension sign. The mean Kujala score significantly improved from 65.5 to 86.1 points (P < 0.05). The mean KOOS (symptom, pain, activities of daily living [ADL], sports, quality of life [QOL]) was 74.4, 92.4, 97.3, 84.1, and 73.2 points, respectively, at final follow-up. On the plane x-ray, patellofemoral alignment was improved postoperatively, and this improvement was maintained at final follow-up. On MRI, in five of 20 cases, the patellofemoral osteoarthritic change was observed at final follow-up. However, in four of these five knees with severe osteochondral lesions, osteochondral fixation or transplantation surgery had been performed. Only one of the remaining 15 knees had a patellofemoral osteoarthritic change observed at final follow-up. ConclusionMiddle- to long-term outcome after MPFL reconstruction with Insall’s proximal realignment at our institution was evaluated, and good clinical results were observed. Most patients who did not have a severe cartilage lesion preoperatively did not develop osteoarthritic change.