The Effect of Anterior Cruciate Ligament Reconstruction on Stride-to-Stride Variability

Constantina O. Moraiti, Nicholas Stergiou, Stavros Ristanis, Haris S. Vasiliadis, Kostas Patras, Cassandra Lee, Anastasios D. Georgoulis

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


Purpose: 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. Level of Evidence: Level III, case control study.

Original languageEnglish (US)
Pages (from-to)742-749
Number of pages8
JournalArthroscopy - Journal of Arthroscopic and Related Surgery
Issue number7
StatePublished - Jul 2009


  • Anterior cruciate ligament reconstruction
  • Approximate entropy
  • Bone-patellar tendon-bone autograft
  • Motion analysis
  • Quadrupled semitendinosus and gracilis tendon autograft

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine


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