Recent advances in joint arthroplasty

transcript

Recent Advances in Joint Arthroplasty

Presenter : Dr Saumya AgarwalJunior resident Dept of Orthopaedics J.N.Medical College

and Dr. Prabhakar Kore Hospital and MRC, Belgaum

So many Recent Advances….

After all it’s a Orthopaedicians choice

INDEXRecent Advances in• Hip Arthroplasty• Knee Arthroplasty• Shoulder Arthroplasty• Elbow Arthroplasty• Ankle Arthroplasty• Spine Arthroplasty• Radial Head Arthroplasty• CMC Joint Arthroplasty• PIP Joint Arthroplasty

Hip Arthroplasty

APPLIED BIOMECHANICS

Goal of THR

Biomechanically sound, stable hip joint by restoration of normal center of rotation of femoral head

The location of center of rotation of femoral head is determined by

1. Vertical offset2. Horizontal(medial) offset3. Anterior offset (Anteversion)

HEAD NECK RATIO

• AFFECTS ROM ,IMPINGEMENT,STABILITY OF ARTICULATION.

Specialized femoral components for replacement of variable length of proximal femur. Stem can be combined with TKR to replace entire femur

Madras Joint Replacement Center 13

Short Stem Hip replacement

Indications for Proxima or short stem Hip replacement

• Any patient with Hip arthritis for whom a total hip replacement is the permanent solution but Proxima will preserve more bone than a total hip replacement.

• Bone stock should be intact.

• Those patients with disease in the head which is more extensive making “ Resurfacing” unsuitable. For eg- Avascular necrosis

Proxima is a bone preserving hip replacement

• Neck portion of femur is preserved

• Only head is removed.

• The shaft of the femur is not entered or reamed, once again preserving bone.

Comparison of total hip & Proxima

• Total hip removes the neck portion

• In short stem replacement neck portion is preserved

Advantages of Proxima

• Less soft tissue dissection• Less bony resection• Large diameter Head- less chance of

dislocation• Fluid film lubrication – leads to less wear of

the implant• Metal on metal bearings- less wear

Hip Resurfacing Surgery

Candidates for hip resurfacing

• Young & active patients with hip arthritis or secondary osteo-arthritis

• avascular necrosis• ankylosing spondylitis• post traumatic arthritis• DDH• Slipped capital femoral epiphysis• Primary OA in young patients

www.hipsurgery.in

Surgical technique Femoral reaming

Technique- Femoral head cemented in

www.hipsurgery.in

Acetabular reaming & component insertion

• Uncemented cup• Fixation by

circumferential fins (Durom)

• Hydoxy apatite coating

• Cobalt chrome molybdenum

• High carbon content

www.hipsurgery.in

Post op x ray

• Proper position of femoral component

• Proper inclination of acetabular component

• Proper depth of acetabular cup

What is Minimally Invasive Hip Surgery?

• A new surgical technique

• Uses traditional hip implants

• Two different techniques, including mini-incision and two-incision.

Traditional VS Minimally Invasive Hip Replacement Surgery

Traditional Hip Replacement Surgery– Proven in clinical studies and

successfully performed for decades

– Allows surgeon full visualization of operative area

– Larger incision (8-10 inches)– More disruption of muscles and

tissues

Minimally Invasive Hip Replacement Surgery– Long-term effects and success

are not established.– Restricted visualization of

operation area. – Smaller incisions (2-4 inches)– Potentially less disruption of

muscles and tissues– May lead to less blood loss

and postoperative pain

Traditional Hip Replacement Surgery– Average hospital stay

is five days– Average recovery

time of approx. 3 months (individuals will vary)

Minimally Invasive Hip Replacement Surgery– May lead to a

shortened hospital stay, less than 5 days.

– May reduce recovery time

Traditional Hip Replacement Surgery

Minimally Invasive Hip Replacement Surgery

Benefits of Minimally Invasive Hip Surgery

• Less trauma to the body.• Healing and rehabilitation potentially

quicker.• Shorter hospital stays • Allows for immediate stability of the hip• Lower risk of dislocation.• Potentially less postoperative pain.• Cosmetically appealing

Ideal Candidate

• Suffering from hip arthritis • Failed response to:

– Medicines– Exercise– Weight-management

• Deciding factors include:– Medical history– Weight– General health– Body structure, including bone structure– Extent and pattern of arthritis

Inappropriate Candidates

• Severely obese (BMI of 40 or greater)• Very muscular • Undergoing complex revision surgeries

Minimally Invasive Hip TechniquesTwo-Incision

• 2 incisions• Approximately 2 inches in length• On both front and rear of thigh• Fluoroscopy may be used.

Mini-Incision• 1 incision• Approximately 3 to 4 inches in length• Either front or rear of thigh• Fluoroscopy is not used.

Techniques: Two Incision vs Mini Incision

Two-Incision Mini-Incision

Recovery After Surgery

• MIH benefits shown in the first 3 months of recovery

• Patient must follow hip precautions:– Not crossing their legs– Take care when bending

• Avoid high-impact and contact sports.

Risk Factors

• Factors that may affect the rate of complications including– Surgeon skill– Weight, age and overall health of the patient– Current lifestyle and activities of the patient– Presence of osteoporosis or other conditions

that weaken bones– Patient compliance with physician instructions

Potential Complications and Risks

• Hematoma– Occurs when blood enters the wound after

surgery. – If excessive, will be drained.

• Hip Fracture– Occurs during or after surgery– Caused by:

• Weak bones• Falling• Failure to follow hip precautions

Potential Complications and Risks

• Infection– About 1% change of infection after surgery

• Dislocation– Occurs when the ball of the hip comes out

of the socket.– Caused by:

• size• Blood clots

The Zimmer Biomet M/L Taper Hip Prosthesis offers a slim anterior / posterior dimension and bone-conserving alternative for patients, while the collarless prosthesis optimizes the clinically proven tapered wedge fixation philosophy while providing secure mediolateral stability.

As a combined system, the M/L Taper with Kinectiv®Technology introduces a system of modular stem and neck components designed to help the surgeon optimally restore the hip joint center intraoperatively by addressing leg length, offset, and version independently, while the broad array of neck options efficiently targets a wide range of male and female anatomies.

What is Dual Mobility ?

Head articulates within a retentive polyethylenePolyethylene is free to move in metalback shell in a NON RETENTIVE way Do not confuse with bipolar cups

Why have Dual Mobility? • Improve prosthetic stability, significantly reduce the risk of dislocation • Increase amplitude of movement before impingement

• To reduce wear, « Low Friction Arthroplasty »

• To reduce shear forces at the bone interface which contribute to implant loosening

Indications:Primary hip replacements, (at risk of dislocation) •Elderly patients (> 65 or 70) •Non compliant patients (dementia, alcohol..) •Tumours •Joint laxity (neuro muscular disorders, age) •DDH•RA•Revisions, The risk of dislocation after revisions increases

Mallory-Head artificial joint using the proximal multiporous coated system, clinical and radiological results were determined to be excellent based on stable osseous integration, low revision rate, and thigh pain.

Knee Arthroplasty

INDICATIONS• Severe arthritis

• Young pts with systemic arthritis with multiple joint involvement

• Osteonecrosis with subchondral collapse of a femoral condyle

• Severe pain from chondrocalcinosis and pseudogout in elderly

• Severe patello femoral arthritis rarely

CONTRA-INDICATIONS

• Recent/current knee sepsis

• Remote source of ongoing infection

• Extensor mechanism discontinuity

• Recurvatum deformity secondary to muscle weakness

• Presence of painless, well functioning knee arthrodesis

Mechanical Alignment

TKA aims at restoring the mechanical axis of the lower limb by:Sequential soft tissue

releases

Correction of bone defects by grafts or prosthetic augments

Prosthetic DesignHi flex design

• Cultural / pt expectation• Cut more posterior

condyle

Preop flexion - most significant - Gatha etal 2008

No difference in ROM - Mehin JBJS 2010

No difference in ROM Sumino Int Ortho 2010

• Small incisions that measure 4- 5 inches

• Cause less pain• Less blood loss• Less requirement for

analgesics• Faster recovery

Minimally invasive knee replacements

Standard TKR incision

Minimally invasive TKR incision

Minimally invasive knee replacements

Incision for MIS knee 4 inch incision for TKR

• Increasing number of patients < 50 years seeking knee replacements.

• Special considerations of material, technique needed. Oxinium knee is an example of a TKR for young patients.

Knee replacements for young patients

Features of Oxinium knee

• Made of Oxinium• Ceramic surface coating• Metal base• 4900 times harder than standard knee prosthesis• Less friction• Durable• Non allergenic to people with Nickel allergy

Advantages of patient specific instruments with Oxinium knee

• Accurate implantation• Life of implant is prolonged to 30 years. • Faster operation time • Less chance of infection• Possible to do both knees in one sitting• Smaller surgical scars

The Persona Knee:

Is the most anatomically accurate size increments in a knee implant system

Provides uncompromising fit

Allows for intuitive alignment accuracy

Facilitates natural knee motion

Reduces the need for surgical compromises, optimizing patient outcomes

The patented ATTUNE GRADIUS™ Curve is the gradually reducing femoral radius designed to provide a smooth transition from stability to rotational freedom through a patient's range of motion.

The LOGICLOCK™ Tibial Base has a patented central locking design that provides the architecture for the system that optimizes kinematics, while reducing backside micromotion to the lowest reported levels in the industry.

The proprietary s-curve of the SOFCAM™ Contact is designed to provide a smooth engagement for gradual femoral rollback and stability in flexion, while reducing stresses transferred to the tibial spine.

The GLIDERIGHT™ Articulation encompasses a trochlear groove designed to accommodate patient variation and soft tissue interaction, and patella components designed to optimize patella tracking while maintaining bone coverage.

Advances in Knee Joint Replacement

• Newer materials which increase longevity of the implant.• Cement-less fixation of knee implants.• Smart tools like the I-Assist provide intra operative navigation.• Validated soft tissue balancing tools – E-Libra• Kinematically aligned knee replacement vs Mechanically aligned

knee replacement. • Biological knee replacements – Can be done in incremental

steps in India with tissue bank assistance.• Customized implants – These are available abroad.

Materials

• Femoral components made of Oxidized zirconium

• Plastic tray made of highly cross linked polyethylene.

• Vitamin E incorporated durable poly inserts

• The technique involves the attachment of active or passive trackers on femur and tibia, which are then tracked by a computer-assisted camera.

• Computer gives real-time feedback about alignment of bony cuts in all three anatomic planes, which allows surgeon to make changes and to measure the accuracy of the bony cuts.

• Computer navigation systems also can aid in determin ing the proper implant size as well as alignment. Soft tissue balancing and measurement of flexion and extension gaps during the procedure are other significant advantages to computer-assisted TKA.

• Objective measurement of the gaps ensures proper soft tissue balancing and gaps that will provide a stable joint throughout a range of motion.

• Another advantage of computer navigation is avoidance of violation of the femoral intramedullary canal, which may reduce blood loss and cardiac-related complications because fewer emboli are placed into the venous system than with placement of an intramedullary alignment rod.

Smart tools

• I-Assist smart tool • Ortho align smart tool.

• Soft tissue balancing tools

ROBOTICS IN THA• ROBODOC autonomously mills a cavity into the

femur for the implantation of a cementless femoral component.

• Two fiducials are inserted preoperatively into the femur (one in the distal supracondylar region and one in the greater trochanter).

• A CT scan is taken of the femur with fine slice images ,transferred to a 3D computer modelling station called ORTHODOC

• Intraoperatively, the surgeon exposes and prepares the femur, cuts off the femoral head.

• The femur is then fixed to the robot base by a special clamp and a bone motion sensor/monitor is activated.

ADVANTAGE

• Overall fit of the implant surface with the cavity is better than 98% in the robot-assisted procedure versus 23% with conventional surgical techniques.

• No intraoperative femoral fractures.

• Improve the long-term performance of the prosthesis as well as improved bone growth around the prosthesis

• The leg-length equality and varus-valgus orientation of the stem were significantly better.

• Reduce the incidence of clinically significant pulmonary embolism during cementless THA.

DISADVANTAGES

• More operative time• More muscle damage leads to higher

dislocation rate.

ROBOTICS IN TKA

• Accuracy of orientation of femoral, tibial and patellar components are important in obtaining proper joint kinematics and has been shown to affect the longevity of total knee arthoplasty.

• Potential benefits of using cementless designs over cemented techniques also become more feasible with the use of robot-assisted TKA.

• Tibial component position was within 2 degrees of neutral, and the overall flatness of the tibial cut was 0.4 to 0.8 mm compared with 0.6 to 1.6 mm with conventional cutting techniques.

• Tibiofemoral alignment between preoperative and postoperative measurements was improved from 2.6 degrees using conventional techniques to 0.8 degrees with the use of robot-assisted TKA.

Total Shoulder Arthroplasty

Description• Prosthesis design alters the

center of rotation by moving it medially and inferiorly

• This increases the deltoid moment arm and deltoid tension

• Enhanced mechanical advantage of deltoid compensates for the deficient rotator cuff

• Deltoid becomes the primary elevator of the shoulder joint

1. Achieve functional range of motion while allowing for adequate soft tissue healing

2. Maximize use of upper extremity for daily activities at or above shoulder height

3. Educate patient to safely manage their rehabilitation and use of their arm throughout post-operative rehabilitation

Goal of Procedure

• Glenohumeral joints with severe arthropathy and severe rotator cuff deficiency or a joint in which a previous TSA has failed (also with cuff deficiency)

• Joint must be structurally and anatomically suited to receive device– Cementless metaglene component

• Functional Deltoid

Indications for RTSA

Resurfacing the shoulder

Total Elbow Arthroplasty

Total Elbow Arthroplasty• Poor bone stock and destruction of joint• Modern linked semiconstrained implants• Advantages

– Undisturbed extensor mechanism– Reliably restored stability– Predictable range of motion– Minimal pain and limited motion

• Disadvantage– Implant-related complications– Limit use of the upper extremity

Implants Selection

Stryker’s Solar Total Elbow

Zimmer’s Coonrad-Morrey Total Elbow

Total Ankle Arthroplasty

Constrained

– Greater stability but with reduced motion

– Increased stresses at the bone – cement – implant interfaces leading to early loosening and failure

Ex – St. George/Buchholz, Imperial College London Hospital, Conaxial and Mayo designs

Unconstrained

– Improved ROM in multiple planes but with reduced stability

– Less stress at the bone – cement – implant interface

Ex – Waugh / Irvine, Smith and Newton Prostheses

‘Old generation’ ankle replacements consisted of a polyethylene tibial component and a metallic talar component.

NEW GEN IMPLANTS

• The new generation implants presently in use can be classified – (a) as two- or three-component designs and

– (b) as fixed or mobile-bearing designs.

The INBONE™ ankle (Boulder, USA)

• This is the only TAA with an intramedullary alignment system design.

• Over 200 INBONE™ ankle replacements have been performed in the USA.

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The ESKA ankle prosthesis (Germany)

TNK prosthesis • FIRST CERAMIC

PROSTHESIS

The tibial stem and the deep sulcus of the talar component accommodating a matching polyethylene surface, allowing

inversion/eversion motion, are characteristic features of the Buechel–Pappas ankle replacement.

Three-component designs

The STAR prosthesis uses two bars for tibial component fixation.

The Scandinavian Total Ankle Replacement (STAR)

Screw fixation is a characteristic element of the HINTEGRA prosthesis.

The SALTO ankle prosthesis ‘fixed-bearing’ version is used in the USA, whereas the original ‘mobile-bearing’ design is used in Europe.

The SALTO Talaris™ anatomic ankle (Tornier)

The Agility prosthesis, a two-component design, requires tibio-fibular fixation.

Benefits of Agility implant– Greater ankle support and longer-term stability

than earlier implants– Multiple sizes for a more precise fit– More natural joint movement than is possible

with ankle fusion surgery

• A unique feature of the Agility is the addition of a syndesmotic fusion to allow load transfer from the tibial component to both bones of the leg.

Spine Arthroplasty

Cervical Intervertebral Total Disc Replacement

Indications• Symptomatic cerνical disk disease in only one

vertebral level between C3 –C7 defιned as neck or arm (radicular) pain, and/or functional/neurologic defιcit with at least one of the following conditions confιrmed by imaging (CT, MRI, or X-rays)

• Herniated nucleus pulposus • Spondylosis (presence of osteophytes) • loss of disk height• Age between 18 and 60 years

Bryan Cervical Disk Replacement

DESIGN FEATURESShell

Wings: anterior stop

Post: “soft” stop in maximum ROM

Internal polished concave spherical surface

External convex surface with porous coating

Low friction, wear resistant, elastic material.2 convex spherical surfaces

Nucleus

The Prodisc-C: Concept for Cervical Disk Arthroplasty (semi-constrained)

Lumbar Intervertebral Total Disc Replacement

SB Charité

• The SB Charité prosthesis is the most widely used so far.

• SB Charité prosthesis has „unconstrained“ kinematics.

SB Charité

• Due to the biconvex shape of the polyethylene core,

the intervertebral disc space also has to be distracted more when using the SB Charité prosthesis as compared to the other types of prosthesis in order not to damage the polyethylene.

A-Mav™

Maverick Implant Design

HA Coating• Calcium phosphorus• Provides a geometry which

is conductive to bony on growth

• Rough surface provides increased friction for a press fit

Prodisc II

• Like the SB Charité prosthesis, it consists of two endplates made of a CrCoMo alloy with a pure titanium Plasmapore® surface to improve osseointegration.

Acroflex disc• The two titanium endplates

are joined together by an HP-100 silicone elastomer core.

• Osseointegration occurs via a rough surface and via small spikes attached to the ventral third.

• The prosthesis is inserted as a whole using centrally inserted distraction forceps.

RADIAL HEAD REPLACEMENT• To prevent proximal migration of the radius• Silicon implant poor outcome : SILICON SYNOVITIS• Titanium/vitallium metallic implant of choice

Indication:• Extensive communition of radial head/excess bone loss• Elbow instability:• essex lapresti lesion,• coronoid fracture,• elbow dislocation,• collateral ligament injury,• olecranon fracture

RADIAL HEAD REPLACEMENT

• LOOSE STEMMED PROSTHESIS• THAT ACTS AS A STIFF SPACER

BIPOLAR PROSTHESIS

• That is cemented into the neck of the radius

COMPLICATIONS:• Overstuffing of joint • capitellar wear problems• Malalignment instability

CMC Joint Arthroplasty

PIP Joint Arthroplasty

REFERENCES

• Joint conclave• Internet• Depuy• Zimmer • Synthes • Campbell textbook of Orthopaedics• Rockwood fracture in Adults• Biomet

QUESTIONS IN EXAMS

Long question • Recent advances in joint replacement surgeries

Short questions• Hip resurfacing• Minimally invasive hip surgery• Computer assisted surgery• Robotics in orthopaedics

LET’S WELCOME THE FUTURE

Recent advances in joint arthroplasty

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