Biomechanical and magnetic resonance imaging evaluation of a single- and double-row rotator cuff repair in an in vivo sheep model.
OBJECTIVE
To investigate the biomechanical and magnetic resonance imaging (MRI)-derived morphologic changes between single- and double-row rotator cuff repair at different time points after fixation.


METHODS
Eighteen mature female sheep were randomly assigned to either a single-row treatment group using arthroscopic Mason-Allen stitches or a double-row treatment group using a combination of arthroscopic Mason-Allen and mattress stitches. Each group was analyzed at 1 of 3 survival points (6 weeks, 12 weeks, and 26 weeks). We evaluated the integrity of the cuff repair using MRI and biomechanical properties using a mechanical testing machine.


RESULTS
The mean load to failure was significantly higher in the double-row group compared with the single-row group at 6 and 12 weeks (P = .018 and P = .002, respectively). At 26 weeks, the differences were not statistically significant (P = .080). However, the double-row group achieved a mean load to failure similar to that of a healthy infraspinatus tendon, whereas the single-row group reached only 70% of the load of a healthy infraspinatus tendon. No significant morphologic differences were observed based on the MRI results.


CONCLUSIONS
This study confirms that in an acute repair model, double-row repair may enhance the speed of mechanical recovery of the tendon-bone complex when compared with single-row repair in the early postoperative period.


CONCLUSIONS
Double-row rotator cuff repair enables higher mechanical strength that is especially sustained during the early recovery period and may therefore improve clinical outcome.
Department of Orthopaedic Surgery, University of Göttingen Medical Centre, Georg-August-University, Germany. m.baums@t-online.de
Mike H
MH
Baums
Gunter
G
Spahn
Gottfried H
GH
Buchhorn
Wolfgang
W
Schultz
Lars
L
Hofmann
Hans-Michael
HM
Klinger
D000818:Animals; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D005260:Female; D008279:Magnetic Resonance Imaging; D017006:Rotator Cuff / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D012756:Sheep