Tendon Reattachment to Bone in an Ovine Tendon Defect Model of Retraction Using Allogenic and Xenogenic Demineralised Bone Matrix Incorporated with Mesenchymal Stem Cells.

Tanujan Thangarajah,Gordon W. Blunn,Shirin Shahbazi,Catherine J. Pendegrass,Simon Lambert,Susan Alexander,Dimitrios Zeugolis

doi:10.1371/journal.pone.0161473

Tanujan Thangarajah, Gordon W. Blunn + Show 5 more

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https://doi.org/10.1371/journal.pone.0161473

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Abstract

BackgroundTendon-bone healing following rotator cuff repairs is mainly impaired by poor tissue quality. Demineralised bone matrix promotes healing of the tendon-bone interface but its role in the treatment of tendon tears with retraction has not been investigated. We hypothesized that cortical demineralised bone matrix used with minimally manipulated mesenchymal stem cells will result in improved function and restoration of the tendon-bone interface with no difference between xenogenic and allogenic scaffolds.Materials and MethodsIn an ovine model, the patellar tendon was detached from the tibial tuberosity and a complete distal tendon transverse defect measuring 1 cm was created. Suture anchors were used to reattach the tendon and xenogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5), or allogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5) were used to bridge the defect. Graft incorporation into the tendon and its effect on regeneration of the enthesis was assessed using histomorphometry. Force plate analysis was used to assess functional recovery.ResultsCompared to the xenograft, the allograft was associated with significantly higher functional weight bearing at 6 (P = 0.047), 9 (P = 0.028), and 12 weeks (P = 0.009). In the allogenic group this was accompanied by greater remodeling of the demineralised bone matrix into tendon-like tissue in the region of the defect (p = 0.015), and a more direct type of enthesis characterized by significantly more fibrocartilage (p = 0.039). No failures of tendon-bone healing were noted in either group.ConclusionDemineralised bone matrix used with minimally manipulated mesenchymal stem cells promotes healing of the tendon-bone interface in an ovine model of acute tendon retraction, with superior mechanical and histological results associated with use of an allograft.

Highlights

The muscles of the rotator cuff play an important role in normal glenohumeral motion and stability
The allograft was associated with significantly higher functional weight bearing at 6 (P = 0.047), 9 (P = 0.028), and 12 weeks (P = 0.009)
Augmentation of Tendon-Bone Healing Using Demineralised Bone Matrix tendon-like tissue in the region of the defect (p = 0.015), and a more direct type of enthesis characterized by significantly more fibrocartilage (p = 0.039)

Summary

Introduction

The muscles of the rotator cuff (subscapularis, supraspinatus, infraspinatus, and teres minor) play an important role in normal glenohumeral motion and stability. Some tears (deemed ‘irreparable rotator cuff tears’) cannot be repaired primarily to bone despite conventional techniques of mobilization and soft-tissue releases because of their size and retraction [1]. They are associated with atrophy and fatty infiltration of the associated rotator cuff muscles: this is reflected in an alteration of their pennation angles, which results in impaired muscle contraction and altered joint biomechanics [2, 3]. We hypothesized that cortical demineralised bone matrix used with minimally manipulated mesenchymal stem cells will result in improved function and restoration of the tendon-bone interface with no difference between xenogenic and allogenic scaffolds

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