schematic illustration of the various fixation methods: (a)direct interference or (passive)...

Schematic illustration of thevarious fixation methods:

(a) direct interference or (passive) noninterference fit;(b) mechanical fixation usingscrews, bolts, nuts, wires, etc.;(c) bone cement;(d) porous ingrowth (biological) fixation;(e) direct chemical bondingusing adhesives or after coatingwith direct bonding material layer;(f) bone cement with resorbable particles;(g) porous ingrowth controlled by using electrical or electromagnetic stimulation

Bone Cement

Polymethylmethacrylate (PMMA) bone cement:– made from methylmethacrylate,

polymethylmethacrylate, esters of methacrylic acid, or copolymers containing polymethylmethacrylate and polystyrene

• Companies:– Johnson & Johnson, Stryker, Zimmer, Smith & Nephew, Exactech, Heraeus Holding, Biomet

Examples of currently used surface coatings on stems ofTHA to enhance both short- and long-term fixation

عوارض احتمالي تعویض مفصل ران           

                                                                   ایجاد لخته هاي خون )داروهاي رقيق كننده ي خون، جوراب كشسان، •

انجام ورزشهايي كه جريان خون را به عضالت پا افزايش دهند، استفاده ازچكمه هاي پالستيكي كه براي تحت فشار قرار دادن

عضالت پا،با هوا باد مي شوند.       شل شدگي پروتز•دررفتگي گوي از كاسه )جا انداختن، استفاده از آتل(•ساييدگي •آسيب به عصب•

Approximate Average Concentrations (ng/ml or ppb) of Metal in Human Body Fluids with and without Total Joint

Replacements

Bone Void Fillers

A resorbable calcium salt bone void filler device is a resorbable implant intended to fill bony voids or gaps of the extremities (leg & hand), spine, and pelvis that are caused by trauma or surgery

• Homework: Find different types of bone fillers?

Knee degrees of freedom

• Flexion – ±50°• IE Rotation – ±25 °• AP Translation - ±25 mm• Axial load – 4500 N

Total Knee Replacement-Partial knee replacement(unicompartmental)– Replacement of one or two parts of knee instead of total.– Retain more of patient natural knee.• Total knee replacement– Resurfaces the bones (tibia and femur) with an implant made of metal and plastic parts.– Medical-grade plastic spacer providing a smooth surface as cartilage

The time of TKRStep I:– If patients answer yes to any of the questions, it may be time to speak with anorthopedic surgeon about knee replacement surgery1. Does the knee hurt one or more days per week?___Yes___No2. Does the pain interfere with sleep? ___Yes___No3. Is it painful to walk more than a block? ___Yes ___No4. Are pain medications no longer working? ___Yes___No5. Is knee pain limiting participation in activities? ___Yes___No6. Has inactivity from knee pain caused weight gain? ___Yes___No7. Have you ever received hyaluronic acid injections? ___Yes___No8. Would it be possible to limit activities for a few months to recover from surgery?___Yes___No9. Are you willing to commit to work hard during rehabilitation for a successfulrecovery? ___Yes___No

Knee joints FDA Approved• Knee joint femorotibial metallic constrained cemented prosthesis• Knee joint femorotibial metal/composite non-constrained cemented prosthesis• Knee joint femorotibial metal/polymer constrained cemented

Examples of new THA and TKA oxidized zirconium components currently gaining popularity because of enhanced mechanical and

biocompatibility properties

Spinal fixation device

Ankle Joint Replacement

Ankle Joint Replacement

Some ankle prostheses

FDA Approved

• Metal/composite cemented semi-constrainedankle prosthesis• Metal/polymer cemented semi-constrainedankle prosthesis• Non-constrained cemented ankle prosthesis– Co-Cr alloy and UHMWPE or UHMWPE –carbon fiber• Companies: Johnson & Johnson, Stryker, Biomet,wright medical technology, Tornier

Shoulder Joint Replacement

Shoulder Joint Prosthesis

Shoulder joints FDA Approved

• Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis

• Shoulder joint metal/polymer semi-constrained cemented prosthesis

• Shoulder joint metal/polymer non-constrained cemented prosthesis

• Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented

• Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis

• Humeral Metal/Polymer Cemented Or Uncemented

Elbow Joint Prosthesis

Wrist Joint Prosthesis

FDA Approved

• Wrist joint carpal lunate polymer prosthesis• Wrist joint carpal scaphoid polymer prosthesis• Wrist joint carpal trapezium polymer prosthesis• Wrist joint polymer constrained prosthesisProximal: A=Scaphoid, B=Lunate,C=Triquetral, D=PisiformDistal: E=Trapezium, F=Trapezoid,G=Capitate, H=Hamate

Finger joint prostheses

Finger joint prostheses

FDA Approved• Phalangeal (hemi- toe) prosthesis– Made of silicone elastomer– Replace the base of the phalanx of the toe– Companies: Wright medical technology, Arthrex, Ascensionorthopedics, Dow Corning• Polymer constrained toe prosthesis– Made of silicon or polyester reinforced silicon– To replace the first metatarsophalangeal (big toe) joint– Companies: Biomet, Smith & Nephew, Zimmer holdings, Dow

corning• Semi-Constrained Metal/Polymer Joint Toe

(Metatarsophalangeal) Prosthesis– Companies: Ascension Orthopedics, Biomet, Acumed

Laminoplasty

A surgical procedure for treatingspinal stenosis by relieving pressureon the spinal cord• The MOUNTAINEER LaminoplastySystem is a complete set of implantsand instruments designed to allow fora systematic approach to laminoplastyprocedures in the cervical spine.Stenosis = abnormal narrowing of a bodily canal or passageway

Cartilage injuries• Disease, accidents and age• Limited repair capability: avascular• Differences in the types of cartilage lesions• No absolutely approved and perfect method• Tissue engineering as a newtreatment method based oncells, scaffolds and growth factors

Methods for Articular Cartilage Repair orRegeneration

Limitations• Needs two surgeries• Ages 15 to 45• Defect size (6mm×7mm)• BMI < 30• Not used in the presence ofosteoarthritis, inflammatorydisease, rheumatoid arthritis• Not used for patients whoseknee meniscus has beensurgically removed

Application of natural biomaterials

Commonly Used Scaffolds in Autologous ChondrocyteImplantation (even distribution and settlement of cells in the defect)

Injections for Knee Pains• Corticosteroid injections for osteoarthritis as an antiinflammatorytreatment• Hyaluronic acid injections as viscosupplementation– Exercise and simple pain medications no longer effectively manageknee pain caused by oseoarthritis– Injections reintroduce healthy joint fluid– Injections restores cushioning and lubricating properties to the kneejoint• Orthovisc® (high molecular weight hyaluronan)• FDA approved non-drug therapy• Made from ultra-pure natural hyaluronan, a naturally occuring lubricantfound in healthy knee joints• Provide up to six months of pain relief

Meniscectomy• Remove the damaged portion of the meniscus– Starts by making several small incisions in the knee, and insertion avery small video camera called an arthroscope– The surgeon watches on a video screen while probing the meniscus– Surgical instruments are used to remove the torn portion of meniscus– A small motorized cutter is used to trim and shape the cut edge of themeniscus– The joint is flushed with sterile saline to wash away debris from theinjury or from the surgery– The entrances are closed with sutures• Tip:– Special fasteners, called suture anchors, are sometimes used to anchorthe torn edges of the meniscus together for younger patients

PTFE Ligament Prosthesis

Ligament Repair

• A graft taken either from the individual with the injury or a donor• Small incisions for insertion an arthroscope to determine the extent of the injury the

appropriate surgical procedure• The torn pieces of the ligament are removed• The pathway for the new ligament is prepared• A guide wire is drilled in the thighbone (femur)• A drill is placed over the guide wire and a hole equal to the graft size is drilled

through the bone• A stitch is connected from the femur to a guide wire and this is pulled through

predrilled holes in the thighbone and shinbone• Fixation of the surgeons choice is then placed in the thighbone• The new ligament graft is then tensioned and a second method of fixation is placed in

the shinbone to secure the new ligament to the surrounding bone• After reconstructing the ligament, the portals are closed with stitches or surgical tape

Fibrin sealantsProduction of a fibrin clot as an adhesive and wound-covering agent• In synthetic process the fibrinogen is at a much higherconcentration (70 mg/ml) than that in human plasma• After mixing fibrinogen polymerized to fibrin monomers and A white

fibrin clot is initiated under the action of thrombin And CaCl2• Aprotinin, an inhibitor of fibrinolysis, may also be Included in solution

A

Advantages of FibrinIt is hemostatic• It adheres to connective tissue• It promotes wound healing• It is biodegradable with excellent tissue tolerance