Biological approaches to the repair and regeneration of the rotator cuff tendon-bone enthesis: a literature review.

Entheses are highly specialised organs connecting ligaments and tendons to bones, facilitating force transmission, and providing mechanical strengths to absorb forces encountered. Two types of entheses, fibrocartilaginous and fibrous, exist in interfaces. The gradual fibrocartilaginous type is in rotator cuff tendons and is more frequently injured due to the poor healing capacity that leads to loss of the original structural and biomechanical properties and is attributed to the high prevalence of retears.

Hard-wired Epimysial Recordings from Normal and Reinnervated Muscle Using a Bone-anchored Device.

Unlabelled: A combined approach for prosthetic attachment and control using a transcutaneous bone-anchored device and implanted muscle electrodes can improve function for upper-limb amputees. The bone-anchor provides a transcutaneous feed-through for muscle signal recording. This approach can be combined with targeted muscle reinnervation (TMR) to further improve myoelectric control.

Application of a Demineralized Cortical Bone Matrix and Bone Marrow-Derived Mesenchymal Stem Cells in a Model of Chronic Rotator Cuff Degeneration.

Background: The success of rotator cuff repair is primarily dependent on tendon-bone healing. Failure is common because weak scar tissue replaces the native enthesis, rendering it prone to reruptures. A demineralized bone matrix (DBM) consists of a network of collagen fibers that provide a sustained release of growth factors such as bone morphogenetic proteins.

Supraspinatus detachment causes musculotendinous degeneration and a reduction in bone mineral density at the enthesis in a rat model of chronic rotator cuff degeneration.

Background: To evaluate biological strategies that enhance tendon-bone healing in humans, it is imperative that suitable animal models accurately reproduce the pathological changes observed in the clinical setting following a tear. The purpose of the present study was to investigate rotator cuff degeneration in a rat, as well as assess the development of osteopenia at the enthesis following tendon detachment.

Methods: Eighteen female Wistar rats underwent unilateral detachment of the supraspinatus tendon.

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.

Augmentation and repair of tendons using demineralised cortical bone.

Background: In severe injuries with loss of tendon substance a tendon graft or a synthetic substitute is usually used to restore functional length. This is usually associated with donor site morbidity, host tissue reactions and lack of remodelling of the synthetic substitutes, which may result in suboptimal outcome. A biocompatible graft with mechanical and structural properties that replicate those of normal tendon and ligament has so far not been identified.

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

Background: Tendon-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.

Microchannel neural interface manufacture by stacking silicone and metal foil laminae.

Objective: Microchannel neural interfaces (MNIs) overcome problems with recording from peripheral nerves by amplifying signals independent of node of Ranvier position. Selective recording and stimulation using an MNI requires good insulation between microchannels and a high electrode density. We propose that stacking microchannel laminae will improve selectivity over single layer MNI designs due to the increase in electrode number and an improvement in microchannel sealing.

Augmentation of Rotator Cuff Repair With Soft Tissue Scaffolds.

Background: Tears of the rotator cuff are one of the most common tendon disorders. Treatment often includes surgical repair, but the rate of failure to gain or maintain healing has been reported to be as high as 94%. This has been substantially attributed to the inadequate capacity of tendon to heal once damaged, particularly to bone at the enthesis.

The effect of adherens junction components on keratinocyte adhesion in vitro: potential implications for sealing the skin-implant interface of intraosseous transcutaneous amputation prostheses.

Amputation places a significant burden on healthcare systems worldwide as patients suffer life-long complications associated with the stump-socket interface. Skin penetrating, osseointegrated implants like intraosseous transcutaneous amputation prostheses, could overcome this, however, they rely on the formation and maintenance of an infection-free seal at the skin-implant interface. Epithelial cell migration around transcutaneous implants creates downgrowth, which leads to infection and implant failure.

Intraosseous transcutaneous amputation prosthesis (ITAP) for limb salvage in 4 dogs.

Objective: To report clinical application of intraosseous transcutaneous amputation prosthesis (ITAP) for limb salvage.

Study Design: Retrospective case series.

Sample Population: Client owned dogs with malignant neoplasia of the distal aspect of the limb.

Modification of titanium alloy surfaces for percutaneous implants by covalently attaching laminin.

Percutaneous implants require a seal at the skin interface. Laminin (L-332) is a component of the basement membrane, integral to epidermal attachment. To enhance the attachment of keratinocytes onto the surface of titanium alloy (Ti(6)Al(4)V), we attached L-332 onto the surface using silanization (L-332==Ti(6)Al(4)V).

Measuring the strength of dermal fibroblast attachment to functionalized titanium alloys in vitro.

The success of intraosseous transcutaneous amputation prostheses (ITAP) relies on soft tissue attachment to prevent infection which leads to implant failure. Fibronectin (Fn) has been shown to enhance dermal fibroblast attachment in vitro, however measurement of cell attachment strength has been indirect; using cell area and immunolocalization of focal adhesion components. In this study, we have developed a flow apparatus to assess the biophysical strength of cell attachment to biomaterials used in ITAP.

Tendon bone healing can be enhanced by demineralized bone matrix: a functional and histological study.

Rotator cuff repair surgery has high failure rates, with tendon reattachment to bone remaining a challenging clinical problem. Increasing the integrity of the healing tendon-bone interface has been attempted by adopting a number of different augmentation strategies. Because of chondrogenic and osteogenic properties we hypothesise that demineralized bone matrix (DBM) augmentation of a healing tendon-bone interface will result in improved function, and a morphology that more closely resembles that of a normal enthesis, compared with nonaugmented controls in an ovine patellar tendon model.

Development of a soft tissue seal around bone-anchored transcutaneous amputation prostheses.

Conventional amputation prosthetics are problematic because they rely on the stump-socket interface for attachment. Intraosseous transcutaneous amputation prostheses (ITAP) could solve these problems; however they rely on the integrity of the soft tissue-implant interface as a barrier to exogenous agents, and in the prevention of downgrowth and marsupilisation. We have used an in vivo animal model to study the soft tissue interfaces around bone-anchored transcutaneous implants.