title: Joint laxity and isokinetic thigh muscle strength characteristics after anterior cruciate ligament reconstruction: bone patellar tendon bone versus quadrupled hamstring autografts.
abstract: OBJECTIVE
  To analyze ligamentous stability and isokinetic strength of knee extensor and flexor muscles after anterior cruciate ligament reconstruction using 2 different autografts with identical fixation.
  
  
  METHODS
  This study implements a comparative case series design.
  
  
  METHODS
  Schulthess Clinic, Switzerland.
  
  
  METHODS
  A total of 153 consecutive patients (n = 87 bone-patellar tendon-bone [BPTB]/66 quadruple semitendinosus/gracilis tendons [QSGT] patients) who underwent BPTB and QSGT surgery were functionally assessed.
  
  
  METHODS
  All patients were functionally assessed (knee extension/flexion isokinetic strength and knee joint laxity) at a mean follow-up time of 11 months.
  
  
  METHODS
  Laxity was measured utilizing the Kneelax arthrometer, whereas isokinetic strength of the knee extensor/flexor muscle groups was measured using the Biodex Multi Joint System 2 (180 degrees/s and 300 degrees/s).
  
  
  RESULTS
  The QSGT group had significantly greater knee joint laxity when compared with the BPTB group (P < 0.001). Furthermore, females in the QSGT group demonstrated the greatest knee joint laxity overall (P < 0.001). Additionally, a significant flexor torque deficiency was demonstrated in the QSGT group (P < 0.001); however, no differences in extensor torque were observed.
  
  
  CONCLUSIONS
  The use of a BPTB autograft achieved better knee joint stability as well as greater knee flexor torque than the QSGT autograft. Both grafts exhibited a similar knee extensor torque deficit, indicating that only quadriceps strength is not graft-dependent.
authors.affiliation: Research Department, Schulthess Clinic, Zurich, Switzerland.
authors.forename: Mario
authors.initials: M
authors.lastname: Bizzini
authors.forename: Mark
authors.initials: M
authors.lastname: Gorelick
authors.forename: Urs
authors.initials: U
authors.lastname: Munzinger
authors.forename: Tomas
authors.initials: T
authors.lastname: Drobny
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D005260:Female; D006801:Humans; D007593:Joint Instability; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness; D018482:Muscle, Skeletal; D019637:Orthopedic Procedures / Q000379:methods*; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000379:methods; D013710:Tendons / Q000637:transplantation*; D016896:Treatment Outcome