The document discusses tendon anatomy, histology, nutrition, healing, and clinical applications of tendon repair and grafting. It covers the 3 phases of tendon graft healing - cellular, collagen synthesis, and remodeling. Primary repair of tendon lacerations is indicated for clean wounds within days of injury. Goals of repair include restoring gliding function while avoiding scar adhesion. Early controlled motion after repair and techniques like tenolysis can improve outcomes.
Can read freely here
https://sethiortho.blogspot.com/
Fracture Healing and
Mechanical stability
Perren`s strain theory
Fracture healing
Indirect Healing
Direct healing
Fixation techniques and stability
Nonunion and Management
Fracture healing
Biological environment
Age
Nutritional status
Blood supply
Metabolic
Mechanical stability
Absolute
Relative
Surgical procedure
Alters biological environment
Selection of fixation
Alters mechanical environment
Mechanical Stability
Parren's strain theory
Strain
Relative deformation of a material when a given force is applied
Relative changes in the fracture gap divided by original fracture gap = L / L
Stability determines the Strain at the fracture site
Stable fixation – less strain
Unstable fixation – high strain
Large gap fracture – less strain
Cross section of the fracture-
Fracture gap strain VS cells response
The degree of inter fragmentary strain appears to govern the cellular response.
Each of these tissues is able to tolerate a different amount of strain:
Perren's strain theory….
When the inter fragmentary strain is <2% bone repair occurs by direct healing
While for intermediate amount of IFS (5–10%) the fracture heals by indirect healing.
Stain theory of healing –Indirect healing
Indirect Healing
Indirect Healing…
Hard callus formation
Indirect Healing
Remodeling Stage
Months to years
Conversion of woven bone into lamellar bone
Formation of Medullary cavity
Return of biomechanical property
Influenced by wolf law – Remodeling based on stress
Stain theory of healing…pseudo arthrosis
Complete instability
Callus is unable to form because the strain is too much for it to tolerate.
The more strain-tolerant fibrous tissue forms
Bone ends are sealed over with cortical bone
Formation of false joint with synovial fluid in the gap
Hypertrophic nonunion
Unstable fracture
Excess callus formation unable to reduce the IFS
Creates a hypertrophic non union
Direct Healing
Anatomically reduced rigid fixed fractures
Formation of cutting cones
>100,000 remodeling units work at time
Direct osteonal remodeling
Without callous
Activation
resorption by osteoclasts
osteoid formation by osteoclasts
Primary osteons
Mineralization
Direct Healing….
Fixation techniques and stability
Relative stability
Intramedullary nailing
Load sharing device
Inter fragmentary micro motion
Fracture gap strain is usually 2-10%
Body responds by forming more soft callus to try and decrease the strain
Fixation of diaphyseal fractures – strength and less duration
Relative stability
Absolute stability
Absolute stability
TBW
Lag screw fixation
Interfragmentary strain,
Nonunion and Management
Nonunion ….
Fracture is fixed rigidly but a gap is present
Direct healing may not be able to bridge the gap
The lack of strain may inhibit callus formation and secondary healing
Predispose to non-union
Management –
Can read freely here
https://sethiortho.blogspot.com/
Fracture Healing and
Mechanical stability
Perren`s strain theory
Fracture healing
Indirect Healing
Direct healing
Fixation techniques and stability
Nonunion and Management
Fracture healing
Biological environment
Age
Nutritional status
Blood supply
Metabolic
Mechanical stability
Absolute
Relative
Surgical procedure
Alters biological environment
Selection of fixation
Alters mechanical environment
Mechanical Stability
Parren's strain theory
Strain
Relative deformation of a material when a given force is applied
Relative changes in the fracture gap divided by original fracture gap = L / L
Stability determines the Strain at the fracture site
Stable fixation – less strain
Unstable fixation – high strain
Large gap fracture – less strain
Cross section of the fracture-
Fracture gap strain VS cells response
The degree of inter fragmentary strain appears to govern the cellular response.
Each of these tissues is able to tolerate a different amount of strain:
Perren's strain theory….
When the inter fragmentary strain is <2% bone repair occurs by direct healing
While for intermediate amount of IFS (5–10%) the fracture heals by indirect healing.
Stain theory of healing –Indirect healing
Indirect Healing
Indirect Healing…
Hard callus formation
Indirect Healing
Remodeling Stage
Months to years
Conversion of woven bone into lamellar bone
Formation of Medullary cavity
Return of biomechanical property
Influenced by wolf law – Remodeling based on stress
Stain theory of healing…pseudo arthrosis
Complete instability
Callus is unable to form because the strain is too much for it to tolerate.
The more strain-tolerant fibrous tissue forms
Bone ends are sealed over with cortical bone
Formation of false joint with synovial fluid in the gap
Hypertrophic nonunion
Unstable fracture
Excess callus formation unable to reduce the IFS
Creates a hypertrophic non union
Direct Healing
Anatomically reduced rigid fixed fractures
Formation of cutting cones
>100,000 remodeling units work at time
Direct osteonal remodeling
Without callous
Activation
resorption by osteoclasts
osteoid formation by osteoclasts
Primary osteons
Mineralization
Direct Healing….
Fixation techniques and stability
Relative stability
Intramedullary nailing
Load sharing device
Inter fragmentary micro motion
Fracture gap strain is usually 2-10%
Body responds by forming more soft callus to try and decrease the strain
Fixation of diaphyseal fractures – strength and less duration
Relative stability
Absolute stability
Absolute stability
TBW
Lag screw fixation
Interfragmentary strain,
Nonunion and Management
Nonunion ….
Fracture is fixed rigidly but a gap is present
Direct healing may not be able to bridge the gap
The lack of strain may inhibit callus formation and secondary healing
Predispose to non-union
Management –
regeneration
Proliferative Capacities of Tissues
Stem Cells
REPAIR BY CONNECTIVE TISSUE
Angiogenesis
Migration of Fibroblasts and ECM Deposition (Scar Formation)
PATHOLOGIC ASPECTS OF REPAIR
DIFFUSION BASED AND VASCULAR CONSTRUCTS, TRANSPORT OF NUTRIENTS AND METABOLITES Vijay Raj Yanamala
he biggest challenge in the field of tissue engineering remains mass transfer
limitations. This is the limiting factor in the size of any tissue construct grown in vitro.
Within the body, most cells are found no more than 100–200mm from the nearest
capillary, with this spacing providing sufficient diffusion of oxygen, nutrients, and waste
products to support and maintain viable tissue. Likewise, when tissues grown in the
laboratory are implanted into the body, this diffusion limitation allows only cells within
100–200mm from the nearest capillary to survive.
Thus, it is critical that a tissue be pre-vascularized before implantation with proper
consideration given to the cell and tissue type, oxygen and nutrient diffusion rates, overall
construct size, and integration with host vasculature. In the laboratory, limited diffusion
of oxygen is the primary reason that construction of tissues greater than a few hundred
microns in thickness is currently not practicable.
Approaches to address this problem generally fall into six major categories:
scaffold functionalization,
cell-based techniques,
bioreactor designs,
(d)microelectromechanical systems(MEMS)–related approaches,
modular assembly,
in vivo systems
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
HOT NEW PRODUCT! BIG SALES FAST SHIPPING NOW FROM CHINA!! EU KU DB BK substit...GL Anaacs
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Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
4. • Tendons are glistening white
anatomic structures interposed
between muscles and bones.
• They transmit the force created in
muscle to bone and make joint
movement possible.
• Tendons may be surrounded by a
bed of loose areolar tissue called
paratenon, or they may reside
within a tunnel of dense fibrous
tissue, the tendon sheath.
5. PARATENON
• The paratenon encases the tendon
in loosely arranged connective
tissue .
• It Consist of type I and type III
collagen fibrils, some elastic fibrils,
and an inner lining of synovial cells.
• The tendon is bathed in a fluid
environment similar to synovial
fluid.
6. • Nestled within the paratenon, the
entire tendon is covered by the
epitenon (also called mesotenon),
a fine, loose connective tissue
sheath containing the vascular,
lymphatic, and nerve supply.
• The epitenon extends deeper into
the tendon between the tertiary
bundles of collagen fibrils as the
endotenon.
• Together, the paratenon and
epitenon are sometimes called the
peritendon.
7. TENDON SHEATH
• The classic two-layered synovial
tendon sheath is present only in
certain tendons as they pass areas
of increased mechanical stress.
• These sheaths span an area from
the metacarpal heads to the
midportion of the distal phalanges.
• The outer layer is the fibrotic
(ligamentous) sheath; the inner
layer is the synovial sheath,
which consists of thin visceral and
parietal sheets.
8. • The parietal layer , it allows
smooth gliding of tendon as
well as provides synovial fluid
nutrition.
• The annular and cruciate
pulleys in these fibrous sheaths
provide mechanical advantage
as they hold tendons close to the
bone while allowing acute
flexion of the interphalangeal
joints
9. BLOOD SUPPLY
• In the hand, tendons are vascularized
along the entire length in a longitudinal
pattern.
• The different sources are vessels that
enter the palm and extend down
intratendinous channels
-vessels that enter from the proximal
synovial fold in the palm,
-segmental vessels that develop from
paired digital arteries and enter tendon
sheaths as vincula,
-vessels that enter the osseous insertions
of the tendon, and
-vessels at the musculotendinous junction.
• The majority of these vessels supply the
dorsal or posterior surface of tendon.
10. • A tendon in an area of low compression is vascularized by
small vessels that enter at multiple levels from the
surrounding areolar tissue.
• Blood flow is low, averaging less than 10 mL per 100 g per
minute.
• In contrast, in compressed areas, such as across a joint space,
nutrition comes from the segmental vincula.
11. • Within the digital sheath, both profundus and sublimis
tendons have relatively avascular segments over the
proximal phalanx; the profundus has an additional short
avascular zone over the middle phalanx. In these avascular
zones, tendons must rely on synovial fluid pumping for
nutrition.
12. HISTOLOGY AND BIOCHEMISTRY
• The basic elements of tendon are collagen bundles (70%), cells, and ground
substance or extracellular matrix, a viscous substance rich in proteoglycans.
• Collagen provides tendon with tensile strength; ground substance provides
structural support for the collagen fibers and regulates the extracellular assembly
of procollagen into mature collagen. Proteoglycans regulate tissue strength
because they determine the size and packing of collagen fibrils.
13. • The collagen fibril diameter in the adult tendon typically ranges
from 100 to 200 nm, but this will vary with tissue loading.
• Tenocytes (or fibrocytes), flat tapered cells sparingly distributed
among the collagen fibrils, synthesize both the ground substance
and the procollagen building blocks of protein.
• Collagen is arranged in hierarchical levels of increasing complexity
beginning with tropocollagen, a triplehelix polypeptide chain. Each
tropocollagen is composed of helical arrangement of two α1(I) and
one Î ±2(I) collagen chains.
• These helical molecules of tropocollagen in turn unite into fibrils,
fibers (primary bundles), fascicles (secondary bundles) that spiral
into tertiary bundles, and finally the tendon itself .
14. Myotendinous and Osteotendinous
Junctions• The myotendinous junction is a highly
specialized anatomic region in the
muscle-tendon unit where tension
generated by muscle fibers is transmitted
from intracellular contractile proteins to
extracellular connective tissue proteins
(collagen fibrils).
The osteotendinous junction is a
specialized region in the muscle-tendon
unit where the tendon inserts into a bone.
In the osteotendinous junction, the
viscoelastic tendon transmits the force into
a rigid bone.
15. Light Microscopic Appearance of Tendon
• Normal tendon consists of dense,
clearly defined parallel and slightly
wavy collagen bundles.
• Collagen has a characteristic
reflective appearance under
polarized light. Between the collagen
bundles, there is a fairly even sparse
distribution of cells with thin wavy
nuclei.
• There is an absence of stainable
ground substance and no evidence
of fibroblastic or myofibroblastic
proliferation. Tendon is supplied by a
network of small arteries oriented
parallel to the collagen fibers in the
endotenon, which is a continuation
and invagination of the outer
epitenon.
Cross section of a tendon showing the arrangement of the fasciculi
and vascular bundles
16. TENDON NUTRITION
• Tendons receive nutrition from both vascular and synovial
systems.
• Synovial fluid diffusion provides rapid delivery of nutrients by
imbibition, whereby fluid is pumped into small conduits in the
tendon surface during digital flexion and extension.
• In the absence of vascular inflow, diffusion alone can provide
adequate nutrition for tendon healing.
• However, for rapid tendon healing and functional gliding to
be achieved, it is important to preserve the integrity of these
two nutritional sources. Compromise to either vincula or
digital sheath will result in less than optimal healing.
18. The healing of tendon grafts may include three phases
(1) Cellular phase: the space between the graft and host tissue is
filled with blood clot, inflammatory cells, and granulation
tissue. Epitenon cells may proliferate and invade to
participate in the repair.
(2) Collagen synthesis phase, beginning at the first week and
lasting for several weeks with extracellular matrix production
along with ongoing revascularization process.
(3) Remodeling phase: during this phase, transplanted graft
gains strength and peritendinous adhesions become loose and
filmy and lose their strength, allowing the graft to glide.
However, it may need 9 months to remodel the collagen
fibers to a relatively normal pattern.
19. • The stages of tendon and graft healing model normal wound
healing.
STAGE OF INFLAMMATION
- lasts 48 to 72 hours after repair. The strength of the tendon
repair is almost entirely supplied by the suture.
- A fibrin clot fills the space between tendon, or between
tendon and graft, while macrophage and inflammatory cells
join the repair site.
- Cells originating from the extrinsic peritendinous tissue, the
epitenon, and the endotenon migrate to the wound, and the
morphologic appearance changes to that of fibroblasts. These
cells proliferate and begin collagen production.
20. PROLIFERATION STAGE
• The fibroblastic or collagen- proliferation stage lasts 5
days to 4 weeks, when scar is deposited.
• The scar tissue is composed of random collagen fibrils, with
type I and type III collagen, along with increased water,
DNA, and glycosaminoglycan content.
• Fibroblast numbers peak at 2 to 3 weeks, then decrease. At this
time, there is relative weakness in the healing tendon ends, and
strength of repair is dependent on the construct and strength of
the holding suture.
21. MATURATION OR REMODELING STAGE
• During the maturation or remodeling stage, the parallel,
longitudinally oriented collagen fibers merge with the
disorganized scar and impart a portion of their normal
physiologic stress through the scar.
• Cross-linking of fibers also imparts an increase in tensile
strength. By 3 to 4 months, the remodeling process is
complete.
22. Extrinsic Versus Intrinsic Healing
• Controversy used to exist in determining whether the extrinsic
cells (coming from peritendinous tissue) or intrinsic cells
(coming from within the tendon, such as tenocyte, endotenon,
or epitenon) produced new collagen.
• Numerous authors have now shown that intrinsic healing is
indeed a pathway to tendon healing.The relative contribution
of extrinsic and intrinsic cells to tendon healing is dependent
on level of initial injury, quality of surgical repair, and
postoperative regimen.
• As a rule, intrinsic cellular healing results in less adhesion
formation
23. Modulators of Tendon Healing
• In the hope of enhancing tendon healing, investigators are
looking at the role of soluble polypeptides in the cellular
events of tendon healing.
• The agents under study include growth factors, hormones, and
chemotactic factors such as fibronectin.
• Nessler and Fujita examined the effect of direct current
electrical stimulation.
• Nelson and Greenough looked at pulsed electromagnetic
fields, with some positive effects on an experimental model.
• Ultrasound may also limit adhesions, assisting in ultimate
functional outcome.
24. • Nonsteroidal anti-inflammatory agents may decrease
adhesion formation.
• Use of hyaluronic acid in decreasing tendon adhesions.
Hyaluronic acid's efficacy is affected by both the concentration
and the molecular weight of the preparation.
26. Repair of Tendon Laceration
• To achieve tendon healing and to attain effortless gliding to
allow full joint motion.
• The challenge has been to repair both flexor tendon and the
surrounding sheath, which is 1 mm away, and have both heal
without being encased in a single scar mass.
GOALS
27. • Bunnell's original principle of
avoiding primary repair of zone II
injuries, between the distal palmar
crease and insertion of the
sublimis tendon, has given way to
immediate primary repair.
• Particular indications for primary
tendon repair are tendon
lacerations in clean wounds with
intact soft tissue, digital
replantation, and tendon injury
with concomitant bone fractures
in which fixation is stable enough
to allow immediate motion of
joints.
INDICATIONS
28. Primary flexor tendon repairs
Indications
Clean-cut tendon injuries
Tendon cut with limited peritendinous damage, no defects in soft-tissue
coverage
Regional loss of soft-tissue coverage or fractures of phalangeal shafts are
borderline indications
Within several days or at most 3 or 4 weeks after tendon laceration
Contraindications
Severe wound contamination
Bony injuries involving joint components or extensive soft-tissue loss
Destruction of a series of annular pulleys and lengthy tendon defects
Experienced surgeons are not available
29. • Matev, Schneider, and others have shown that primary repair
of tendon injury within the flexor sheath may be performed in
a delayed fashion without compromise to outcome.
• Gelberman's review, however, suggested that better
biomechanical results can be achieved with immediate repair
of tendon injury compared with repairs delayed 7 or 21 days.
TIMING OF REPAIR
30. GUIDELINES FOR REPAIR
Surgical technique and tissue handling are critical to the
quality of the result after tendon repair.
Meticulous atraumatic technique is necessary to avoid
tendon or tendon sheath injury and injury to the blood supply.
Because the blood supply to tendons in the sheath lies dorsally,
strangulation is avoided by placement of core sutures in the
relatively avascular, anterior portion of the tendon.
Repeated efforts to retrieve a retracted tendon may result in
trauma to the tendon or sheath, and one should not hesitate to
extend the exposure.
31. Several suture materials for flexor tendon repairs of that 4-0
monofilament polypropylene or braided polyester sutures
are reasonable choices.
Barrie et al recommended that 3-0 suture be considered for
tendon repairs when early active motion is planned.
Suture method for tendon repair should not be unduly
complex, and there should be a smooth edge between cut
ends
32. The repaired tendon must not bulge outside the confines of the
tendon sheath.
The circumferential, epitendinous suture performs two functions.
It avoids exposing the cut ends of
tendons, minimizing extrinsic healing by
adhesions and the development of gap
formation, and adds to the tensile
strength of the repair.
Several authors have advocated the placement of the epitenon
suture first, as a technique to align the tendon ends, to provide
stability during repair and to keep the free ends from fraying.
Papandrea compared two methods of Kessler suture repair of
tendons and reported a 22% increase in tensile strength when the
34. • Vascularity is a critical factor determining the final result after
tendon repair. Hypovascularity is reflected in decreased matrix
synthesis in the tendon, decreased tensile strength and motion,
and greater adhesion formation.
• In cases of severe injury, with damage to vincula or when
sublimis tendon was excised, the results of tendon repair were
worse.
BLOOD SUPPLY
35. • The critical elements that
must be preserved within
the flexor sheath are the
A2 and A4 pulleys.
PRESERVATION AND RECONSTRUCTION
OF THE FLEXOR SHEATH
36. • They provide the moment arm
for digit flexion and inhibit
bowstringing .
• Repair of the fibrous flexor
sheath restores the closed
synovial space for nutrition and
lubrication.
• With sheath repair, there are
additional pitfalls, including
excessive scarring, loss of
vascularity, and limitation of
tendon gliding.
37. EARLY MOTION AND TENSILE STRESS
• Early controlled postoperative motion improves tendon tensile
strength and excursion.
• This salutary effect is thought to be secondary to increased
intrinsic healing, increased collagen formation, facilitated
pumping of synovial fluid, and possible disruption of early
vascular budding and adhesion formation.
• The tensile stress initiated by early motion has been shown to
increase the rate and organization of collagen synthesis
38. Improvements in Suture Technique
• Myriad core suture techniques have been developed to
minimize gap formation and to avoid rupture with early
postoperative motion, especially active motion.
• Biomechanical testing in numerous four-strand and six-strand
repairs attests that the strength of a flexor tendon repair is
roughly proportional to the number of suture strands that cross
the repair site.
• The advantages of achieving greater tensile strength and
decreased gap formation with multistrand repairs must be
weighed against possible increase in bulk of the tendon,
increased gliding resistance within the sheath, potential
compromise of vascularity, and increased operating time.
39.
40. • Uncontrollable factors that affect outcome are the extent of
soft tissue and flexor sheath injury and the vascular supply to
the injured tendon ends.
• Controllable factors that affect the outcome of tendon repair
are the amount of stress placed on the repair (postoperative
regimen), surgical technique, and type of suture repair.
41. Tenolysis
• When tendon adhesions inhibit motion of the digit, better
function may be gained through tenolysis.
• Tenolysis may be performed after primary tendon repair, after
tendon grafting, or after two-staged tendon grafting.
• This should not be attempted until tissue equilibrium, that is,
suppleness of soft tissue as well as of joints, is achieved.
• The patient's passive motion should exceed his or her active
motion, but regardless, surgery should be considered when
there is a plateau in therapy.
• The optimal time may be 3 to 4 months after initial tendon
repair.
42. • Tenolysis is optimally performed under initial local anesthesia
to allow the patient to actively flex the digits and to confirm
adequate release of all adhesions tethering the tendon.
• If tenolysis fail, it may become necessary to remove the
repaired tendon and replace this with a tendon graft.
44. History
• Tendon transplantation was reported as early as 1904 in the
California State Journal of Medicine, in which Hunkin
reported the transplantation of the semitendinosus part of the
biceps to restore a boy’s leg function.
• In 1905 and 1910, Lange and Kurtz respectively reported
tendon graft transplantation.
• In the 1920s, Tuner, Simmonds, and Evans also reported cases
of tendon transplantations.
• Tendon graft may primarily be used in hand surgery to repair
flexor profundus injury, extensor pollicis longus tendon
rupture.
• when there is an unsuitable bed for tendon grafting, a two-
stage tendon grafting procedure is necessary. This technique
was first described by Carroll and Bassett and Hunter.
46. REQUIREMENTS FOR TENDON
GRAFTING
• Before tendon grafting, there must
be complete wound healing, with
adequate soft tissue coverage.
• There must be an absence of
edema and induration.
• The skeletal alignment must be
satisfactory and stable, and
optimally, there should be full
range of passive motion of the
joint.
Contraindications for grafting
• An bsence of any of these
elements,
• Adherent extensor tendons,
• Planned capsulotomy for stiff
joints,
• Need for pulley reconstruction
47. To achieve success in tendon grafting, Pulvertaft
listed the following requirements:
• Mobile digit with minimal scarring and at least one digital
nerve intact;
• Meticulous surgical technique;
• Cooperative patient;
• Careful, graduated mobilization.
48. TWO-STAGED TENDON GRAFTING
• Severely scarred wound beds, as in digits with bone exposure.
• Simultaneous fracture fixation and when flexor and extensor
tendons must be repaired.
• An injured tendon bed that might provide poor nutrition to a
tendon graft
• Joint stiffness, when capsulotomy is planned,
• where local finger flaps are needed to provide soft tissue
coverage in severe crushing injuries.
• Two-staged tendon grafts may be indicated in failed zone II
flexor tendon repairs.
Indications
49. Timing Considerations for Two-Staged Tendon
Graft
• The initial stage consists of removal of scarred tissue; reconstruction
of key pulleys; repair of digital nerve; and then placement of a
pliable tendon rod, composed of a woven Dacron spacer that is
encased in silicone, within the tendon pulleys.
• After a minimum period of 3 months, a pseudosheath will have
formed around the silicone rod as a foreign body reaction, providing
a surface for the future autologous tendon graft to glide on.
• As the temporary rod is removed, the ultimate goal in two-staged
tendon grafting is survival of the tendon graft within the
pseudosheath before vascular adhesions are formed.
• Tendon grafts are not mobilized until 3 weeks postoperatively, after
the transplanted tendon has obtained sufficient vascularity from its
bed.
50. DONOR SITES FOR TENDON GRAFTS
• Potential tendon donors should have adequate length, be in a
superficial location for ease of harvest, have little or no functional
loss, and be thin enough to become revascularized yet strong enough
to move the digit.
• In order of preference,potential tendon donors are the following:
Palmaris longus
Plantaris
Extensor digitorum longus
Extensor indicis proprius
Flexor digitorum superficialis
Spare parts Tendon graft harvested from an
irreparably injured structure.
51. • Palmaris longus
Advantage: easy access, no functional
loss, and good caliber for digital flexors.
Disadvantage: may be absent in 10% and
may be too short for fingertip to wrist
grafts.
52. • Plantaris
Advantage: long tendon, with no
functional loss; easily braided if a
thicker graft is required.
Disadvantage: requires a second
operative site, and there is no test
to determine its presence
beforehand. It may be missing in
20% of cases, and if it is not
present on one side, only one in
three will have a plantaris tendon
on the other side .
53. • Extensor digitorum longus
Advantage: reliable source of graft from the second, third, and
fourth toes and may provide a long, many-tailed graft without
injury to epitenon.
Disadvantage: possible flexion deformity of the toes.
54. • Extensor indicis proprius
Advantage: within the same
operative field.
Disadvantage: short length; may
lead to a small extensor lag.
55. • Flexor digitorum superficialis Not
really recommended; harvest may
cause proximal interphalangeal
joint hyperextension and may
decrease flexion power.
• Spare parts Tendon graft
harvested from an irreparably
injured structure.
56. RESULTS OF TENDON GRAFT
• Kraemer et al, in a review of 220 consecutive grafts, reported
an incidence of 1.1% tendon graft disruption for one-staged
tendon grafts compared with an incidence of 7.6% graft
disruption in two staged tendon grafts.
• One incredible report described the complication of
transplantation of the median nerve as a tendon graft in four
cases. This serves as a somber reminder of the importance of
careful identification of nerve during dissection and clinical
determination of the presence or absence of the palmaris
longus tendon preoperatively.
58. • None of the available autologous tendon grafts is able to meet
all the requirements of an ideal tendon graft.It is almost not
possible completely to avoid functional disturbance to the
donor area where a tendon graft is harvested
• This becomes a major concern when large quantities of
autologous tendon grafts are needed to repair severe tendon
injury and defect. Therefore it has been a challenge in plastic
surgery for long time. To address this concern, several
strategies have been proposed and developed.
60. Tendon allograft
• Liu reported the use of refrigerated flexor tendon graft for
second-stage tendon graft and the results showed 63% had
good flexion, 21% fair, and 16% poor; and 8% had good total
active motion, 71% fair, and 21% poor.
• It was concluded that allograft could be applied for tendon
repair but was inferior to autograft.
61. Artificial tendon
• Nondegraded materials to substitute tendon tissue.
• The difficulty in healing between host tissue and artificial
tendon, fibrotic tissue formation, and the fatigue of implanted
materials remain the challenges to functional repair.
62. Tissue engineering
• It is able to generate autologous graft without causing donor
site morbidity.The two key factors in tendon engineering are
scaffold materials and seed cells.
• Regarding seed cells, tenocytes,dermal fibroblasts, and bone
marrow stem cells (BMSC) have become the candidates for
tendon engineering.
63. Tissue Engineering Strategies for
Tendon and Ligament Regeneration
Tissue Engineering and Regeneration
Cell-Based Strategies for Tendon and
Ligament Tissues
Design and Fabrication of 3D Sophisticated
Scaffolds
Electrospinning
Electrochemical Alignment Technique
64. Tissue Engineering and Regeneration
• Tissue engineering and regenerative medicine proposes
alternative approaches combining living agents, the cells, with
3D structures to mimic the biophysical and chemical cues of
native extracellular matrix, and/or bioactive molecules to
biochemically stimulate cells and the tissue milieu, to meet the
demanding requirements of tissue regeneration.
65. Cell-Based Strategies for Tendon and Ligament Tissues
• Tendon and ligament resident cells are an obvious choice since these
cells are harvested from the target tissue and an eventual level of
epigenetic memory could match the desired cell response to meet
regeneration in damaged tendons or ligaments.
• In 2007 Bi and co-workers discovered a tendon stem/progenitor cell
population with functionally attractive features including universal
stem cell characteristics such as clonogenicity, multipotency and self-
renewal capacity, and with the capability to generate a tendon-like
tissue after in vitro expansion and in vivo transplantation .
66. • Pluripotent embryonic stem cells (ESCs) are an alternative
source to tendon cells, whose potential for the treatment of
tendon injuries has been demonstrated in a patellar defect of a
rat model , resulting in improved mechanical and structural
properties without teratoma formation
• Induced pluripotent stem cells (iPSCs) technology also
presents value for tendon and ligament regeneration, as iPSCs
can be reprogrammed into a wide range of cell.
67. Design and Fabrication of 3D Sophisticated
Scaffolds
• A key challenge in tendon and ligament TE is exactly
the recreation of 3D scaffolding biomaterials that can
mimic this unique architecture and support tissue
regeneration while remaining mechanically competent
• 3D structures that would recreate tendon
microenvironment with specific topographical and
biophysical cues such as the substrate geometry and
topography of fiber based scaffolds.
• The incorporation of growth factors (GFs) and other
bioactive molecules within a 3D scaffold can also
improve the biofunctionality of the system.
68. Ideal tendon scaffold :
1. Biodegradability with adjustable degradation rate
2. Biocompatibility before, during, and after degradation
3. Superior mechanical properties and maintenance of
mechanical strength during the tissue regeneration process
4. Biofunctionality: the ability to support cell proliferation and
differentiation, extracellular matrix secretion, and tissue
formation
5. Processability: the ability to be processed to form desired
constructs of complicated structures and shapes, such as
woven or knitted scaffolds.
69. • Major categories of scaffold materials for tendon engineering
include:
- poly (α-hydroxy acids),
- collagen derivatives,
- acellular tendon,
- xenogenic acellular extracelluar matrix,
- silk derivatives, and
- polysaccharides.
70.
71. Electrospinning
• Electrospinning produces long continuous fibers with
controlled diameter from nanometers to microns.
• The advantage of electrospinning is it produce fibrilar systems
better mimic the nanoscale morphological structure of tendon
and ligament ECM, in order to provide the topographical cues
and promote cells contact guidance, increasing the potential
for regeneration
• This technique also enables the production of fibers from
different polymers including those from natural origin, such as
collagen, chitosan, hyaluronic acid and silk fibroin; or
synthetic, for example poly(e-caprolactone) (PCL),
poly(glycolide) (PLGA), poly(L-lactide) (PLA).
72.
73. Electrochemical Alignment Technique
• Producing anisotropically aligned collagen bundles through a
process based on the pH gradient created between two parallel
electrodes .
• This strategy was firstly proposed for TE of connective tissues
by Akkus group , that have been developing this technique,
culminating in a recent proposed system for the production of
continuous electrochemically aligned collagen (ELAC) threads
74. A Schematic of the rotating electrode electrochemical alignment device
75. Future
• Functional repair of massive tendon tissue defect remains a challenge in
plastic surgery not because of surgical technique, but rather due to the lack
of autologous tendon graft.
• As reported in the literature, current experiments demonstrate the
possibility of generating autologous tendon graft via a tissue-engineering
approach.
• One future direction is to employ a proper bioreactor system with dynamic
mechanical loading to generate engineered autologous tendon graft and
therefore to enhance matrix production and maturation of in vitro-
engineered tendon tissues.
• In addition, design of a proper scaffold material with enhanced mechanical
strength would also help to provide an engineered tendon graft that is
strong enough for functional requirements after in vivo implantation.
• The other potential direction is to employ acellular allogenic/xenogenic
tendon tissue to reconstitute tendon graft given that new methods can be
applied to facilitate cell penetration