About the Authors

Ann M. Hepping

a.m.hepping@umcg.nl

Affiliation Department of Rehabilitation Medicine, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands

Joris J. W. Ploegmakers

Affiliation Department of Orthopedics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands

Jan H. B. Geertzen

Affiliation Department of Rehabilitation Medicine, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands

Sjoerd K. Bulstra

Affiliation Department of Orthopedics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands

Martin Stevens

Affiliation Department of Orthopedics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: AH JP. Performed the experiments: AH. Analyzed the data: AH JP JG SB MS. Contributed reagents/materials/analysis tools: AH JP JG SB MS. Wrote the paper: AH JP JG SB MS.