Evidence of knee extensor dysfunction during sit-to-stand following distal femoral extension osteotomy and patellar tendon advancement in young adults with cerebral palsy: A pilot study

Elizabeth R. Boyer, Jean L. Stout, Jennifer C. Laine, Sarah M. Gutknecht, Lucas Henrique Oliveira, Meghan E. Munger, Michael H. Schwartz, Tom F. Novacheck

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

A distal femoral extension osteotomy with patellar tendon advancement (DFEO + PTA) is a common treatment for individuals with cerebral palsy (CP) who walk in crouch. Musculoskeletal modeling suggests that the typical patella baja position post-DFEO + PTA may limit one's abilities to perform sit-to-stand (STS) tasks; however, STS function has not been assessed. Our purpose was to compare how well individuals who received a DFEO + PTA can perform a 5-times STS test (FTSST) eight or more years after surgery compared to their peers who did not receive a DFEO + PTA (non-DFEO + PTA group). Twenty-one participants completed the task (12 DFEO + PTA, 9 non-DFEO + PTA). Three-dimensional kinematics and kinetics were captured. Kinetics were non-dimensionalized to facilitate group comparisons. Non-DFEO + PTA participants performed the FTSST moderately faster than the DFEO + PTA group (median(IQR), 14.6(9.3) seconds vs. 20.3(10.1) seconds, non-parametric effect size ɣ = 0.97, p = 0.241). Peak negative knee power was larger for the non-DFEO + PTA group (Mean ± SD, −0.063 ± 0.025 vs. −0.048± 0.020, Cohen's d = 0.66, p = 0.165). A similar but weaker trend was observed for negative hip power (median(IQR) −0.120(0.066) vs. −0.105(0.044), ɣ = 0.43, p = 0.671). Both groups used their hips approximately twice as much as their knees to perform the task. The functional deficit among DFEO + PTA participants may be due to patella baja decreasing the knee extensor moment arm, which concurs with the modeling prediction. The group differences may also be due to the non-DFEO + PTA group being slightly higher functioning. Future research is warranted to determine if optimizing patella position during a DFEO + PTA may improve unaided STS function without compromising gait improvements.

Original languageEnglish (US)
Pages (from-to)527-532
Number of pages6
JournalGait and Posture
Volume58
DOIs
StatePublished - Oct 2017

Bibliographical note

Funding Information:
This work and Elizabeth Boyer’s position are supported by the Gait and Motion Outcomes Fund of the Gillette Children’s Foundation . The study sponsors had no role in the study design, collection, analysis and interpretation of data, writing of the manuscript, or the decision to submit the manuscript for publication. The authors would like to thank the staff of the James R . Gage Center for Gait & motion Analysis for their assistance in data collection. Appendix A

Publisher Copyright:
© 2017 Elsevier B.V.

Keywords

  • 5-times sit-to-stand test
  • Crouch gait
  • Distal femoral extension osteotomy
  • Flexed-knee gait
  • Patella baja
  • Patellar tendon advancement

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