Does footprint preparation influence tendon-to-bone healing after rotator cuff repair in an animal model?
OBJECTIVE
The aim of this study was to investigate the influence of footprint spongialization and radiofrequency ablation on rotator cuff repair outcomes compared with an untreated group in a rat model.


METHODS
We randomly assigned 189 Sprague-Dawley rats to either a spongialization, radiofrequency ablation, or untreated group. After separation of the supraspinatus tendon from the greater tubercle, the footprint was prepared by removing the cortical bone with a burr (spongialization), was prepared by ablating soft tissue with a radiofrequency ablation device, or was left unaltered (untreated). Biomechanical testing (after 7 weeks, n = 165) and histologic analysis after 1 and 7 weeks (n = 24) followed reinsertion.


RESULTS
The mean load to failure was 17.51 ± 4.46 N/mm(2) in the spongialization group, 15.56 ± 4.85 N/mm(2) in the radiofrequency ablation group, and 19.21 ± 5.19 N/mm(2) in the untreated group. A significant difference was found between the spongialization and radiofrequency ablation groups (P = .0409), as well as between the untreated and radiofrequency ablation groups (P = .0014). There was no significant difference between the spongialization and untreated groups (P = .2456). The mean area of fibrocartilage transition, characterized by the presence of type II collagen, was larger after 1 and 7 weeks in the spongialization group (0.57 ± 0.1 mm(2) and 0.58 ± 0.1 mm(2), respectively) and untreated group (0.51 ± 0.1 mm(2) and 0.51 ± 0.2 mm(2), respectively) than in the radiofrequency ablation group (0.11 ± 0.1 mm(2) and 0.4 ± 0.1 mm(2), respectively) with P < .05 and P < .01.


CONCLUSIONS
The results of this study show that radiofrequency ablation of the footprint results in a poor biomechanical and histologic outcome in an animal model. No preparation of the footprint has the same effect as spongialization.


CONCLUSIONS
Different techniques of footprint preparation in rotator cuff repair may influence tendon-to-bone healing.
Department of Orthopaedic Surgery, University Hospital of Munich-Campus Grosshadern, Munich, Germany. Electronic address: andreas.ficklscherer@med.uni-muenchen.de.
Andreas
A
Ficklscherer
Department of Orthopaedic Surgery, University Hospital of Munich-Campus Grosshadern, Munich, Germany.
Thomas
T
Loitsch
Department of Orthopaedic Surgery, University Hospital of Munich-Campus Grosshadern, Munich, Germany.
Michaela
M
Serr
Department of Orthopaedic Surgery, University Hospital of Munich-Campus Grosshadern, Munich, Germany.
Mehmet F
MF
Gülecyüz
Department of Orthopaedic Surgery, University Hospital of Munich-Campus Grosshadern, Munich, Germany.
Thomas R
TR
Niethammer
Department of Medical Informatics, Biometry and Epidemiology, Ludwig-Maximilians-University, Munich, Germany.
Hans-Helge
HH
Müller
Anatomische Anstalt, Ludwig-Maximilians-University, Munich, Germany.
Stefan
S
Milz
Department of Orthopaedic Surgery, University Hospital of Munich-Campus Grosshadern, Munich, Germany.
Matthias F
MF
Pietschmann
Department of Orthopaedic Surgery, University Hospital of Munich-Campus Grosshadern, Munich, Germany.
Peter E
PE
Müller
D000818:Animals; D001178:Arthroplasty / Q000379:methods*; D002130:Calcium Phosphates / Q000494:pharmacology*; D004195:Disease Models, Animal; D006811:Humerus / Q000473:pathology / Q000601:surgery*; D010012:Osteogenesis / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017006:Rotator Cuff / Q000473:pathology / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D013710:Tendons / Q000473:pathology / Q000601:surgery*; D014945:Wound Healing / Q000187:drug effects* / Q000502:physiology
D002130:Calcium Phosphates; C020243:calcium phosphate