title: Study of patellar kinematics after reconstruction of the medial patellofemoral ligament.
abstract: BACKGROUND
  Medial patellofemoral ligament reconstruction is currently the technique of choice for the treatment of patellar instability. But what should be the most appropriate graft tension for optimal restoration of patellofemoral kinematics?
  
  
  METHODS
  Six freshly frozen cadaveric knees were studied, the three bone segments were respectively equipped with opto-reflective markers. The acquisitions were made using the Motion Analysis System®. Six successive acquisitions were performed for each knee under different levels of graft tension.
  
  
  RESULTS
  With an intact medial patellofemoral ligament, the medial patellar tilt increased up to a mean value of 2.02° (SD 3.1), the medial patellar translation gradually increased up to a mean value of 3.3mm (SD 2.25) with a slight lateral rotation over the first 30° of knee flexion with a maximum mean value of 1.22° (SD 0.8) at 20° of knee flexion. Reconstruction of the medial patellofemoral ligament was performed using different levels of tension applied to the graft. Only 10 N of graft tension could restore normal patellar tilt, lateral shift and rotation, with results approximating those measured on healthy knee.
  
  
  CONCLUSIONS
  This study confirms the role of the medial patellofemoral ligament in providing adequate patellar stability during the first 30° of knee flexion. According to our findings, a 10 N tension applied to the graft appears sufficient to ensure proper control of patellar tracking whereas 20, 30 and 40 N of tension are excessive tension values inducing a major overcorrection in all studied parameters.
authors: Laboratoire de Physiologie de l'Exercice, Saint Étienne, France. r_philippot@yahoo.fr
authors: Remi
authors: R
authors: Philippot
authors: Bertrand
authors: B
authors: Boyer
authors: Rodolphe
authors: R
authors: Testa
authors: Frédéric
authors: F
authors: Farizon
authors: Bernard
authors: B
authors: Moyen
mesh_terms: D002102:Cadaver; D006801:Humans; D010329:Patella / Q000502:physiology* / Q000601:surgery; D017847:Patellar Ligament / Q000502:physiology* / Q000601:surgery*; D057071:Patellofemoral Joint / Q000502:physiology* / Q000601:surgery*; D016059:Range of Motion, Articular / Q000502:physiology*; D019651:Plastic Surgery Procedures / Q000379:methods*; D013314:Stress, Mechanical; D016896:Treatment Outcome