title: The effect of anterior cruciate ligament reconstruction on stride-to-stride variability.
abstract: OBJECTIVE
  The purpose of our study was to investigate the functional outcome after anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BPTB) and quadrupled semitendinosus and gracilis tendon (ST/G) autografts by evaluating stride-to-stride variability.
  
  
  METHODS
  Six patients with BPTB and 6 patients with STG ACL reconstruction, 2 years postoperatively, and 6 healthy control subjects walked on a treadmill at a self-selected pace while 2 minutes of continuous kinematic data were recorded with a 6-camera optoelectronic system. Stride-to-stride variability was calculated from the knee flexion/extension data using the nonlinear measure of approximate entropy, which estimates the regularity of movement patterns over time.
  
  
  RESULTS
  ACL reconstruction affects stride-to-stride variability. Both the BPTB and the ST/G groups had significantly larger approximate entropy values than the healthy controls. No differences were found between the BPTB and the ST/G approximate entropy values.
  
  
  CONCLUSIONS
  After ACL reconstruction using either BPTB or quadrupled ST/G, there is increased gait variability as compared to healthy individuals. This could be caused by the altered neuromuscular activity found in ACL-reconstructed limbs.
  
  
  METHODS
  Level III, case control study.
authors: Orthopaedic Sports Medicine Center of Ioannina, Department of Orthopaedic Surgery, University of Ioannina, Ioannina, Greece.
authors: Constantina O
authors: CO
authors: Moraiti
authors: Nicholas
authors: N
authors: Stergiou
authors: Stavros
authors: S
authors: Ristanis
authors: Haris S
authors: HS
authors: Vasiliadis
authors: Kostas
authors: K
authors: Patras
authors: Cassandra
authors: C
authors: Lee
authors: Anastasios D
authors: AD
authors: Georgoulis
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D005684:Gait; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000601:surgery*; D008297:Male; D019651:Plastic Surgery Procedures / Q000379:methods; D020127:Recovery of Function; D016896:Treatment Outcome