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• This self-learning activity was approved for 1.0 Category A ARRT CE credits by the AHRA
• Directed readings, home study courses, or internet activities reported in a biennium may not be repeated for credit in the same or any subsequent biennium
COMPANY CONFIDENTIAL © COPYRIGHT 2016-2017 ConforMIS, Inc. 2
Outline
COMPANY CONFIDENTIAL© COPYRIGHT 2016-2017 ConforMIS, Inc. 3
KNEE ANATOMYIMAGINGOA PATHOLOGYSURGICAL TREATMENTSPOST SURGICAL FIT ASSESMENT
HIP ANATOMYIMAGINGOA PATHOLOGYSURGICAL TREATMENTS
Knee Anatomy
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Osseous Structures Femur-
Longest, largest, strongest skeletal bone
Cylindrical shaft made up of cortical bone and fat filled medullary
Condyles defined by trochlea anteriorly and intercondylar notch posteriorly
• Image from:http://en.wikipedia.org/wiki/Femur
Knee Anatomy
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Osseous StructuresPatella-
Flat triangular sesamoid bone marking the anterior most portion of the knee joint
Thick superior border (base) and pointed inferior border (apex)
Cancellous bone enveloped by the quadriceps tendon
Image from: http://www.fpnotebook.com/_media/orthoLegPatellaAntGrayBB255.gif
Knee Anatomy
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Osseous Structures Tibia-
Large superior portion, head, divided into two distinct portions, the medial and lateral condyles, separated by the tibial spine
Flat superior surface is called the plateau
Articulates with the femoral condyles Tibial tuberosity found on the anterior
portion serves as an articulation point for the patellar ligament
Fibula- Most slender of the long bones Articulates anteriorly and laterally with
the lateral tibial condyle
Images from:http://en.wikipedia.org/wiki/Tibiahttp://en.wikipedia.org/wiki/Knee
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Medial femoral condyle
Femoral shaft, distal end
Lateral femoral condyle
Patella
Medial tibial plateau
Head of fibula
Lateral tibial plateau
Knee Anatomy
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Femoral shaft, distal end
Patella
Tibial plateau
Head of fibulaTibial Tuberosity
Femoral condyles
Knee Anatomy
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Cartilage Dense connective tissue
Made up of chondrocytes which produce the extracellular matrix of water, collagen, and proteoglycan
Collagen is mostly type II, provides strength and structure No blood supply, nourishment is supplied by synovial fluid
Thickness Normally between 2 and 5mm’s Thickness can be correlated with highest peak pressure areas. The thickest cartilage in the
body is found in the patellofemoral joint Four distinct zones Superficial zone- highest collagen content which is aligned parallel to the articular surface,
lowest concentration of proteoglycan, 10% to 20% of the overall thickness Transitional zone- 40% to 60% of the overall thickness, collagen organization is random,
composed almost exclusively of proteoglycans Radial zone- distributes load and resists compression with parallel oriented highly organized
collagen fibers, and lowest water content Calcified cartilage zone- contains the tidemark which signals the transition between calcified
and uncalcified cartilage
Knee Anatomy
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Articular Cartilage
Knee Anatomy
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Joint Support External Support
Fibrous Capsule Encloses the joint, consists of
synovial membrane, thin connective tissue which secretes synovial fluid. This thick, high viscosity fluid helps lubricate the knee and reduce friction.
Extracapsular Ligaments Anterior - Patella ligament Lateral – Lateral collateral ligament Medial – Medial collateral ligament Posterior- Oblique popliteal ligament
and arcuate ligamentImage from:http://papruddenmor.blogspot.com/2011_05_01_archive.html
Knee Anatomy
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Joint Support Internal Support
Anterior cruciate ligament (ACL) – provides rotation for the joint and prevents displacement anteriorly
Posterior cruciate ligament (PCL)- prevents posterior draw
Image from:
http://www.ehealthmd.com/yms_images/anterior_cruciate_375.jpg
Knee Anatomy
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Menisci (from Greek meniskos, “crescent”) Medial and Lateral Fibrocartilaginous concave semicircles Articulates with the tibial plateaus Provides gliding surface for knee movement and absorbs tension
Knee Anatomy
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Muscular SupportExtensorsQuadriceps femoris muscle group
Rectus femorisVastus lateralis,Vastus medialusVastus intermediusFlexorsHamstring muscle group SemitendinosusSemimembranosusBiceps femorisAssisting musclesGracilisSartoriusPopliteus
Vastus medialusQuadriceps tendon
Cancellous bone
Vastus lateralis
Biceps femorisSemimembranosus
Cortical bone
Sartorius
Knee Anatomy
Knee Anatomy
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Lateral collateral ligament
Anterior cruciate ligament
Medial compartment
Lateral compartment
Lateral femoral condyle
Medial femoral condyle
Anterior cruciate ligament
Head of the fibula
Tibial plateau
Knee Anatomy
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Patellofemoral compartmentQuadriceps tendon
Patellar tendon
Tibial spine
Posterior cruciate ligament
Cartilage bone interface
Articular cartilage
Lateral meniscus
Knee Imaging
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Knee anatomy and pathology is generally demonstrated using
Routine radiographs, CR/DRCT with or without arthrogram contrastMR with or without arthrogram contrast
Knee Imaging
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CRAPLateralTangential (sunrise)Full Leg – used for alignment measurement
DemonstratesCartilage loss/Joint space narrowingOsteophytes/bone spursSubchondral cystsSclerosisBone marrow edemaTraumatic injuries
Knee Imaging
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UnacceptableAcceptable
AP - Position central ray at right angles to the joint space with no rotation. The resulting image should demonstrate the epicondyles in profile and the intercondylar eminence of the tibia centered within the intercondylar fossa of the femur
Knee Imaging
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Acceptable Unacceptable
Lateral -Position central ray at right angles to the joint space with no rotation of the knee. The resulting image should demonstrate the posterior aspects of the femoral condyles superimposed.
Knee Imaging
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CTDemonstrates:
Joint space narrowingSubchondral cysts Sclerosis Osteophyte formations
CT ArthrogramThe use of diluted contrast in joint delineates articular cartilage and ligaments
MRIDemonstrates
Grade of articular cartilage damageLigaments integrityMeniscal tears
*Knee MR protocols vary from site to site and can be dependent on the system
used to acquire the images*
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Knee Pathology Pathology commonly associated with patients considering a
knee arthroplasty Osteoarthritis (OA) – defined as chronic inflammation characterized by
degeneration of the joints causing pain, stiffness, and swelling. OA is sometimes referred to as degenerative joint disease (DJD). Radiographically OA can be identified by the presence of osteophytes, bone edema, sclerosis, joint space narrowing and cyst formations.
Osteochondritis Defects (or Dissecans) (OCD) is characterized by cracks that occur in the articular cartilage and the underlying subchondral bone as a result of decreased blood flow. Avascular necrosis (AVN) or bone death as a result of the loss of blood flow leaves the articular cartilage vulnerable. Fragmentation of cartilage and bone, and subsequently loose bodies occur within the joint space, causing pain and additional damage. Radiographically loose bodies (bone fragments) can be seen. MR images demonstrate and stage OCD lesions in the cartilage.
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Osteoarthritis (OA)Morbidity
Affects as many as 26.9 million AmericansOne of the most common causes of disability due to limitations in joint movement. By age 40 almost 90% of the American population will have some form of OA in their weight-bearing joints OA results in 632,000 joint replacements each year300,000 TKR surgeries annually in the US for end-stage arthritis of the knee joint.Causes ObesityGeneticsTraumaMetabolic disordersSymptomsPain SwellingLoss of mobility
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OsteoarthritisJoint space narrowing
AP Lateral
Osteophyte formation
Tangential View (aka sunrise or merchant view)
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OsteoarthritisJoint space narrowing
Note- Because the image was acquired bilaterally neither knee is demonstrated in a true AP position since the central beam was focused between the knees.
Weight bearing AP knees
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Osteoarthritis
Image from:http://www.washingtonknee.com/knee-treatments/knee-osteoarthritis/
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ICRS Hyaline Cartilage Lesion Classification System
Grade 1- Superficial lesions, cracks, and indentationsGrade 2 - Fraying, lesions extending down to <50% of cartilage depthGrade 3 - Partial loss of cartilage thickness, cartilage defects extending down to >50% of cartilage depth as well as down to calcified layerGrade 4 - Complete loss of cartilage thickness, bone only
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Grade 4 articular cartilage loss- exposed subchondral bone, complete loss of cartilage
Grade 3 articular cartilage loss - >50% Grade 3 articular
cartilage loss - > 50%
Grade 4 articular cartilage loss- exposed subchondral bone, complete loss of cartilage
Cartilage LossMR images
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Grade 3 articular cartilage loss - >50%
Grade 3 articular cartilage loss - > 50%
Grade 4 articular cartilage loss- exposed subchondral bone, complete loss of cartilage
Grade 4 articular cartilage loss- exposed subchondral bone, complete loss of cartilage
Cartilage LossCT Arthrogram images
Subchondral CystMR images
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Grade 3 articular cartilage loss - > 50%
Osteophyte formation
Osteophyte formation
Subchondral cystSubchondral cyst
Subchondral cyst
Subchondral cyst
Subchondral CystCT Images
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Grade 3 articular cartilage loss - > 50%
Osteophyte formation
Osteophyte formation
Subchondral cystSubchondral cyst
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SclerosisCR Images
Sclerotic changes – increased bone density
Sclerotic changes – increased bone density
Bone Marrow EdemaMR Image
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Bone marrow edema
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Results From interrupted blood flow to the area Injury to the cartilage and underlying bone
Osteochondritis Defect (OCD)
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Osteochondritis Defect (OCD)
Stage Appearance on MRI & Stability of lesion Stage 1- Articular Cartilage Damage only Stage 2 - Cartilage injury with underlying fracture
a. Surrounding bony edema b. Without edema
Stage 3 - Detached but non-displaced fragment Stage 4 - Detached and displaced fragment
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Stage II OCD
Stage II OCD
OCDMR images
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Stage II OCDStage II OCD
Stage III OCDStage IV OCD
OCDMR images
Surgical Treatments - Knee
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Surgeons-Seek the least invasive methodEncourage bone preservation
Less bleeding and post surgical painShorter recovery timesStill have bone to work with for potential revisions; Prosthesis failure rate requiring revision is ~1 percent per year
Surgical Treatments - Knee
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Arthroscopy – via a scope inserted through a small incision the surgeon views the joint capsule and can perform small repairs including removal of damaged cartilage and any loose bodies.
Hemi-Arthroplasty –
Uni-compartmental Arthroplasty – this procedure replaces only the damaged area of a single joint compartment with a prosthetic device.
Duo-compartmental Arthroplasty – this procedure replaces only the damaged area of the patella femoral joint and either the medial or the lateral compartment with a prosthetic device.
Osteotomy – a high tibial osteotomy involves removal of a wedge shaped piece of bone that results in realignment allowing the patients weight to be distributed away from the damage compartment.
Total Knee Arthroplasty – involves replacing all joint surfaces
Surgical Treatments - Knee
“The success of primary TKR in most patients is stronglysupported by more than 20 years of followup data. Thereappears to be rapid and substantial improvement in thepatient's pain, functional status, and overall health-relatedquality of life in about 90 percent of patients; about 85 percentof patients are satisfied with the results of surgery.”
-NIH Consensus Statement on Total Knee Replacement
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Surgical Treatments - Knee
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ConforMIS iUni® is a Uni-Compartmental Device
ConforMIS iTotal® is a Total Knee Device
ConforMIS iDuo® is a Bi-Compartmental Device
ConforMIS CT Order Form
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ConforMIS CT ProtocolPatient IdentificationDICOM data reflects patient’s legal name with supporting documentation.
Patient PositionThe patient’s foot is perpendicular to the table.Toes up, use positioning aids if available.Device in the opposite knee? Bend that knee prior to acquiring any images to avoid scatter (see image). If available use an artifact reduction technique.No pillows or sponges under the knee or ankle of interest.Immobilization is essential, remind the patient to hold as still as possible.Remove foreign objects from field.
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ConforMIS CT ProtocolExam Acquisition and Scan Review (also see side two)Bilateral Imaging is acceptable. Please reconstruct each leg independently.Review all images before the patient leaves the scan table. Anatomy cut-off? Reconstruct to include all anatomy. Motion or positional changes detected? All anatomic areas must be reacquired in their entirety.
Exam Archive and Transfer— Send all images to ConforMIS ASAPRetain a permanent copy of the study. Retain the raw data for as long as possible.Send ALL acquired data including the scout, images and dose page.Send via ConforMIS secure web, cloud sharing networks, direct connection or overnight priority shipping.
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Protocol BuildWe recommend building a ConforMIS protocol in your CT scanner(s) with all of the appropriate rangesTable increment should not exceed slice thicknessKV/MaS Settings should be set at your standard setting for each of the anatomic ranges to be scanned. ConforMIS suggests employing dose reduction techniques whenever possible. All scans should be acquired in the helical/spiral mode, rotation speed not less than 1sec, pitch as close to 1:1 as possible, using the body filterFrom the full leg scout the hip, knee and ankle images may be acquired in a single scan acquisition (alternatively these anatomic areas can be acquired in separate series) Provide reconstructed series in the coronal and sagittal planes of the kneeSend all images that are acquired including the scout and dose page if available*
ConforMIS CT Protocol
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Examples of Unacceptable Motion for ConforMIS Protocol CT Scans
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Examples of Unacceptable Motion for ConforMIS Protocol CT Scans
Multiple areas of excessive motion
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Examples of Unacceptable Motion for ConforMIS Protocol CT Scans
Motion is difficult to see on coronal reconstruction image. It is essential to review all series to detect motion.
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Examples of Unacceptable Motion for ConforMIS Protocol CT Scans
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Examples of Unacceptable Motion for ConforMIS Protocol CT Scans
The “wavy” appearance evident on these images indicates a problem with table motion. It can also happen when the gantry tilt is not at zero, although it may read zero. These issues need to be addressed before scanning ConforMIS protocol studies
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Post Surgical Radiographic AssessmentRoutine CR images are acquired as part of a clinical
assessment of patients post knee arthroplasty to evaluate for common post operative complications that can cause pain and the need for revision surgeries.
Assess for fit – overhang or underhang of either component can lead to post–op pain
Alignment – one of the goals of PKR or TKR is to restore mechanical alignment
Loosening – Failure of PKR and TKR can be associated with component loosening
Osteolysis – bone reabsorption can occur in the area of the prosthetic
Wear – can occur in some of the components of the prosthetic
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Post Surgical Radiographic AssessmentProper positioning is critical- unless directed to do so
by your radiologists or the orthopedic surgeon avoid bilateral images. The central beam should be directed at the knee joint
Weight bearing full leg –assess for alignment and leg length
AP and Lateral – assess for component position and fit
Tangential (aka sunrise or merchant view) – demonstrates the PF joint
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Post Surgical Radiographic AssessmentAPAcceptable positioning Poor positioning
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Post Surgical Radiographic AssessmentLateral
Acceptable positioning Poor positioning
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Post Surgical Radiographic AssessmentSunrise or Merchant View
Acceptable positioning Poor positioning
Hip Anatomy
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• Image and information from: http://www.healthpages.org/anatomy-function/hip-structure-function-common-problems/
Osseous StructuresHip
Ball (femoral head) and socket joint (acetabulum) joining the pelvis and femur
Acetabulum – composed of the innominate bone which includes the ilium, pubis, and ishium forming the socket into which the femoral head fits
Ilium
Ischium
pubis
Hip Anatomy
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Osseous Structures
Image from:http://www.wikiradiography.net/page/Hip+Radiographic+Anatomy
Hip Anatomy
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• Image and information from: https://www.studyblue.com/notes/note/n/practical-2-structure-set-2/deck/8022588
• http://www.healthpages.org/anatomy-function/hip-structure-function-common-problems/
CartilageLabrum- The labrum is a
fibrocartilaginous structure that outlines the acetabular socket, usually triangular in shape
Hip Anatomy
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• Image and information from: http://mywwwzone.heckyeahllc.netdna-cdn.com/wp-content/uploads/2010/07/liofemoral-ligament.png
• http://www.healthpages.org/anatomy-function/hip-structure-function-common-problems/
LigamentsIliofemoral ligament -
strongest ligament in the body
Ischiofemoral ligamentsPubofemoral
These ligaments surround the hip joint providing stability
Hip Anatomy
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Hip motion is performed when several muscles act simultaneously. Several muscles are responsible for each directional motion. Some play a primary role in carrying out the motion and others function in a secondary role.
Hip Anatomy
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Muscles of the Hip – allow for movement, most contribute to more than one type of movementFour Main Groups
Gluteal group - gluteus maximus, gluteus medius, gluteus minimus, and tensor fasciae latae.
Adductor group - adductor brevis, adductor longus, adductor magnus, pectineus, and gracilis
Iliopsoas group - iliacus and psoas major Lateral rotator group - externus and internus obturators, the
piriformis, the superior and inferior gemelli, and the quadratus femoris.***The rectus femoris and satorius contribute to hip motion but are generally considered as primarily knee muscles***
Hip Anatomy
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• Image from: https://en.wikipedia.org/wiki/Muscles_of_the_hip
Hip Anatomy
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Hip MovementFlexion - BendingExtensions - StraighteningAbduction – Moving the leg outward away from the bodyAdduction - Moving the leg outward away from the bodyMedial rotationLateral rotationCircumduction
Hip Anatomy
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Flexion -Iliopsoas group -
iliacus and psoas major
Rectus femorisSatoriusTensor fascia lataePectineusAdductors longus
and brevisGracilis
Extension -Gluteus MaximusSemitendinosusBiceps FemorisSemimembranosus
Hip Anatomy
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Adduction -Adductor brevisAdductor magnusAdductor longusAdductor minumusPectineusGracilisObturator externus
Abduction –Gluteus MediusGluteus MinimusTensor Fascia Latae
Hip Anatomy
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Medial Rotation -Gluteus mediusGluteus minimusTensor fascia lataeAdductor brevis and
longusAdductor magnus
Lateral Rotation -Superior gemellusInferior gemellusObturator externusObturator internusQuadratus femorisPiriformis
Diagnostic Imaging
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Hip anatomy and pathology is generally demonstrated using
Routine radiographs, CR/DRCT with or without arthrogram contrastMR with or without arthrogram contrast
Diagnostic Imaging
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CR – Protocol variable by site but generally
AP Full pelvis - usually for the initial evaluationAffected hip only – subsequent evaluations
Lateral
DemonstratesJoint narrowingSclerosisOsteophytesBone cysts
Diagnostic Imaging
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AP – Full Pelvis - Position the central ray at the mid point between syphysis pubis and ASIS. Internally rotate the patients foot 15o to 20o. Ensure there is no rotation.
Image from: https://www.dreamstime.com/photos-images/medical-xray-spine-pelvis.html
Diagnostic Imaging
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AP – Unilateral - Position the central ray perpendicular to the femoral neck in question, at the mid point between syphysis pubis and ASIS over head of femur. Internally rotate the patients foot 15o to 20o. Ensure there is no rotation.
Image from : https://www.google.com/search?q=Hip+Radiograph&biw=1920&bih=897&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjR56vUi7fOAhUCSBQKHW1jDXIQ_AUIBigB#imgrc=VwiKQMXwndKEaM%3A
Diagnostic Imaging
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AP oblique– Demonstrates the lateral aspects of the femoral head and trochanters. Patients hips and knees are flexed 90o with the feet up, soles facing or touching if possible, and the knees abducted 45o (frog leg). The CR should be placed between the ASIS and the pubic symphysis angled cephalad 10-15o. For unilateral imaging center on the affected acetabulum.
Information and image from: http://cdn.auntminnie.com/user/documents/content_documents/X-Ray_Patient_Positioning_Manual_080402.pdf
Diagnostic Imaging
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CTDemonstrates
Joint space narrowingSubchondral cysts Sclerosis Osteophyte formationsReconstructions
Axial Sagittal Coronal images
CT ArthrogramThe use of diluted contrast in joint delineates articular cartilage and ligaments and some soft tissue structures
MR Demonstrates
Grade articular cartilage damageLigaments integrityMeniscal tears
*Hip MR protocols vary from site to site and can be dependent on the system used to acquire the
images*
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Osteoarthritis (OA)
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Osteoarthritis
Image from: http://www.parkclinic.com.au/home/conditions-treatment/hip/hip-osteoarthritis/
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Grading Hip Osteoarthritis (OA)Radiographic Assessment
Grade 0 - NormalGrade 1 – Possible joint space narrowing and small osteophytes Grade 2 – Joint space narrowing, small osteophytes, sclerosis in acetabulumGrade 3 – Marked joint space narrowing, small osteophytes, sclerosis and cysts, with deformity of the femoral head and acetabulumGrade 4 – Extreme joint space narrowing, bone on bone, large osteophytes and severe deformities
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Osteoarthritis CT Images Sclerosis
Osteophyte
Cysts
Joint space narrowing
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Osteoarthritis CT Images
Sclerosis
Osteophyte
Cysts
Joint space narrowing
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Osteoarthritis CT Images
Femoral head deformityJoint space narrowing
Osteophyte
Cysts
Sclerosis
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Surgical Treatment of Hip OAPatients requiring hip arthroplasty
have moderate to severe arthritis in the hip, including osteoarthritis, rheumatoid arthritis or post-traumatic arthritis, that causes pain and/or interferes with daily living
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Surgeons-Seek the least invasive methodEncourage bone preservation
Less bleeding and post surgical painShorter recovery timesStill have bone to work with for potential
revisions; Approximately 15% of hip arthroplasties annually in the US are revisions
Surgical Treatment of Hip OA
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Arthroscopy – via a scope inserted through a small incision the surgeon views the joint capsule and can perform small repairs including removal of damaged cartilage and any loose bodies.
Osteotomy – Acetabular bone cuts are made to realign the hip to a more natural position
Varus Rotational Osteotomy (VRO) – Corrects femoral neck valgus anatomy (too straight)
Pelvic Osteotomy – Addresses acetabular deformities
Total Hip Arthroplasty – involves the removal of the femoral head and damaged surface of the acetabulum. The replacement implant consists of a metal or ceramic ball (replaces femoral head) on a femoral stem , a metal socket (replaces the acetabulum) and a liner between the ball and socket to provide a gliding surface.
Surgical Treatment of Hip OA
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Post Surgical Radiographic Assessment CR images – AP, Lateral, Frog lateral and or cross table lateral are
acquired as part of a clinical assessment of patients post knee arthroplasty to evaluate for common post operative complications that can cause pain and the need for revision surgeries.
AP and Lateral – Must include full femoral stem and cement. Assess for component loosening, stem failure and infection
Frog lateral – Evaluate the proximal portion of the femoral component
Cross table lateral – Evaluate the position of the acetabular component and the integrity of the surrounding osseous structures
Weight bearing or push pull views – Demonstrates implant loosening or component wear
Full leg – Determine leg length differences