title: Effects of medial patellofemoral ligament reconstruction on patellar tracking.
abstract: OBJECTIVE
  Medial patellofemoral ligament (MPFL) reconstruction has been performed to treat recurrent patellar dislocation. However, the effects on patellar tracking have not been well documented, particularly in patients. The purpose of this study is to compare patellar tracking pattern and chondral status at MPFL reconstruction with those at second-look arthroscopy.
  
  
  METHODS
  Between 1999 and 2008, 71 patients with recurrent patellar dislocation underwent MPFL reconstruction using a double-looped semitendinosus tendon. Of these, 25 knees in 24 patients underwent second-look arthroscopy (at 6-26 months after initial surgery), forming the subject for the present study. No other surgical procedures such as tibial tuberosity transfer, lateral release, or osteotomy were performed in any patients. To assess the patellar tracking pattern, the position of the patella on femoral groove was evaluated arthroscopically during passive knee motion through lateral suprapatellar portal.
  
  
  RESULTS
  Before MPFL reconstruction, the patella in all patients was shifted laterally throughout the entire range of knee motion. Immediately after MPFL reconstruction, patellar malalignment was corrected in all cases. On second-look arthroscopy, two different patellar tracking patterns were observed. In 9 knees, the patella was located on the center of the femoral groove throughout the range of motion. Meanwhile, in the remaining 16 knees, the patella was shifted laterally at knee extension and migrated to the center of femoral groove with increased knee flexion. No significant deteriorations in chondral status were seen on second-look arthroscopy.
  
  
  CONCLUSIONS
  The present study revealed that not all improved patellar trackings after MPFL reconstruction remained intact at follow-up. Chondral status in patellofemoral joint was not aggravated by MPFL reconstruction.
  
  
  METHODS
  Therapeutic studies, Level IV.
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan. keikita@hera.eonet.ne.jp
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kita
authors.forename: Shuji
authors.initials: S
authors.lastname: Horibe
authors.forename: Yukiyoshi
authors.initials: Y
authors.lastname: Toritsuka
authors.forename: Norimasa
authors.initials: N
authors.lastname: Nakamura
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Yonetani
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Mae
authors.forename: Ken
authors.initials: K
authors.lastname: Nakata
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Konsei
authors.initials: K
authors.lastname: Shino
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy; D005260:Female; D006801:Humans; D008023:Ligaments, Articular / Q000601:surgery*; D008297:Male; D010329:Patella / Q000601:surgery*; D031222:Patellar Dislocation / Q000601:surgery*; D057071:Patellofemoral Joint / Q000293:injuries* / Q000601:surgery; D011183:Postoperative Complications; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures; D055815:Young Adult