The effectiveness of demineralized cortical bone matrix in a chronic rotator cuff tear model.
BACKGROUND
The purpose of this study was to assess the effect of demineralized bone matrix (DBM) on rotator cuff tendon-bone healing. The hypothesis was that compared with a commercially available dermal matrix scaffold, DBM would result in a higher bone mineral density and regenerate a morphologically superior enthesis in a rat model of chronic rotator cuff degeneration.


METHODS
Eighteen female Wistar rats underwent unilateral detachment of the supraspinatus tendon. Three weeks later, tendon repair was carried out in animals randomized into 3 groups: group 1 animals were repaired with DBM (n = 6); group 2 received augmentation with the dermal scaffold (n = 6); and group 3 (controls) underwent nonaugmented tendon-bone repair (n = 6). Specimens were retrieved at 6 weeks postoperatively for histologic analysis and evaluation of bone mineral density.


RESULTS
No failures of tendon-bone healing were noted throughout the study. All groups demonstrated closure of the tendon-bone gap with a fibrocartilaginous interface. Dermal collagen specimens exhibited a disorganized structure with significantly more abnormal collagen fiber arrangement and cellularity than in the DBM-based repairs. Nonaugmented repairs exhibited a significantly higher bone mineral density than in DBM and the dermal collagen specimens and were not significantly different from control limbs that were not operated on.


CONCLUSIONS
The application of DBM to a rat model of chronic rotator cuff degeneration did not improve the composition of the healing enthesis compared with nonaugmented controls and a commercially available scaffold. However, perhaps the most important finding of this study was that the control group demonstrated a similar outcome to augmented repairs.
The John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, The Royal National Orthopaedic Hospital Trust, Stanmore, Middlesex, UK. Electronic address: tanujan1@hotmail.com.
Tanujan
T
Thangarajah
The John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, The Royal National Orthopaedic Hospital Trust, Stanmore, Middlesex, UK.
Frederick
F
Henshaw
The John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, The Royal National Orthopaedic Hospital Trust, Stanmore, Middlesex, UK.
Anita
A
Sanghani-Kerai
The Shoulder and Elbow Service, The Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK.
Simon M
SM
Lambert
The John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, The Royal National Orthopaedic Hospital Trust, Stanmore, Middlesex, UK.
Gordon W
GW
Blunn
The John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, The Royal National Orthopaedic Hospital Trust, Stanmore, Middlesex, UK.
Catherine J
CJ
Pendegrass
D062088:Acellular Dermis; D000818:Animals; D001672:Biocompatible Materials; D015519:Bone Density; D001857:Bone Matrix; D002908:Chronic Disease; D000071538:Cortical Bone; D005260:Female; D051381:Rats; D017208:Rats, Wistar; D000070636:Rotator Cuff Injuries / Q000601:surgery / Q000628:therapy*; D054457:Tissue Scaffolds; D014945:Wound Healing
D001672:Biocompatible Materials
Animal model; enthesis healing; rotator cuff; scaffold; shoulder; tendon-bone; tissue engineering