J Knee Surg 2013; 26(05): 347-356
DOI: 10.1055/s-0033-1341580
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Characterization of Initial Microfracture Defects in Human Condyles

Caroline D. Hoemann
1   Department of Chemical Engineering, Ecole Polytechnique, Montreal, Quebec, Canada
,
Yoann Gosselin
1   Department of Chemical Engineering, Ecole Polytechnique, Montreal, Quebec, Canada
,
Hongmei Chen
1   Department of Chemical Engineering, Ecole Polytechnique, Montreal, Quebec, Canada
,
Jun Sun
2   Department of Research & Development, BioSyntech/Piramal Healthcare Canada, Laval, Quebec, Canada
3   Department of Clinical Studies, University of Guelph, Guelph, Ontario, Canada
,
Mark B. Hurtig
3   Department of Clinical Studies, University of Guelph, Guelph, Ontario, Canada
,
Alberto Carli
4   Department of Orthopaedic Surgery, McGill University, Montreal, Quebec, Canada
,
William D. Stanish
5   Orthopaedic and Sport Medicine Clinic of Nova Scotia, Dalhousie University, Halifax, Nova Scotia, Canada
› Author Affiliations
Further Information

Publication History

29 October 2012

13 January 2013

Publication Date:
25 March 2013 (online)

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Abstract

Microfracture (MFX) is a cartilage repair technique that depends on cell migration from marrow-rich trabecular bone cavities into the cartilage lesion. This study tested the hypothesis that MFX awls with distinct geometry generate different hole shapes and variable bone marrow access in condyles with Grade III to IV lesions. Lateral and medial condyles from total knee arthroplasty (N = 24 male and female patients, 66 ± 9 years) were systematically microfractured ex vivo to 2 and 4 mm deep and the bone holes analyzed by micro-computed tomography. Subchondral bone in lesional condyles showed different degrees of sclerosis up to 2 mm deep (“porous,” sclerotic, extremely dense). MFX holes ranged from 1.1 to 2.0 mm in diameter, and retained the awl shape with evidence of slight bone elastic rebound and bone compaction lining the holes that were increased by wider awl diameter and deeper MFX. Marrow access was significantly diminished by sclerosis for all three awls, with an average marrow access varying from 70% (nonlesional bone) to 40% (extremely dense bone). This study revealed that subchondral bone sclerosis can reach a critical limit beyond which MFX creates bone compaction and fissures instead of marrow access.