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8/7/2019 Parvizi_UKA

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UKA: When Would I Do It?

Professor of Orthopaedic Surgery

Vice chairman for Research

The Rothman Institute at Thomas

Jefferson University Interest:

Regenerative Medicine

Tissue engineering

Outcome Research

Design: Self Protective Smart Implants

Enjoys Biking, Hiking, Travel, Reading

and Opera

Contact: www.neareastspine.orgJavad Parvizi , MD, FRCS
http://www.neareastspine.org/http://www.neareastspine.org/


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UKA: When Would I Do It?

Javad Parvizi MD

Professor

Rothman Institute at Thomas JeffersonUniversity, Philadelphia

SPINE Meeting, Beirut June 24-26, 2010


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Research support:

NIH OREF

DOD

Aircast

MTF

Stryker Orthopaedics Pfizer

The Knee Society

Kimberly Clark

Ortho McNeill

Adolor

Cubist

3M

KCI

Zimmer

Biomet

Consultant for:

Stryker Orthopaedics

Intellectual Property: Smartech

Smith and Nephew

Stryker Orthopeadics

CyruMed

Conflict of Interest


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Unicompartmental Arthritis

Surgical Options

High Tibial Osteotomy

Unicondylar Knee Arthroplasty

Total Knee Arthroplasty

Arthrodesis

Arthroscopy


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History

Introduced in 1972 (Unicondylar)

Flat all-polyethylene tibialcomponent in sagittal plane

Conforming design in frontal plane

Polyethylene sizes 7.5mm, 9mm,

12.5mm, custom


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History

1976-Insalls original series at 2-4 year follow-up:

Medial replacement (19)-25% Excellent, 32% Good

Lateral replacement (5)-60% Excellent, 40% Good

POOR RESULTS AS COMPARED TO TKA

Insall J, Walker P. Unicondylar knee replacement. Clin Orthop. 1976


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Why such poor results?

5/8 fair and poor results due to patellofemoral complaints

15/24 (63%) had patellectomy

3/8 components loosened

Flat polyethylene Cement was found embedded in the unreplaced articular

surfaces

Patients were not allowed to flex knee for 10-14 days

Insall J, Walker P. Unicondylar knee replacement. Clin Orthop. 1976; 00(120):83-85.

Insall J, Aglietti. A five to seven-year follow-up of unicondylar arthroplasty. J Bone Joint

Surg Am. 1980 Dec; 62(8):1329-37.


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Classic IndicationsKozin SC and Scott R. Unicondylar knee arthroplasty. JBJS. 1989

Unicompartmental disease

Age>60

Low demand Weight 90o


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ContraindicationsThornhill RS, Scott RD. Unicompartmental total knee arthroplasty. Orthop Clin North Am.

1989

Inflammatory arthritis

Hemachromatosis Gout/Pseudogout

Neuropathic Arthropathy

Beware of bicondylarosteonecrosis


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UKA vs. HTO IndicationsThornhill TS. Unicompartmental knee arthroplasty. Clin Orthop. 1986

UKA HTO

Age >70


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6%

13/228(Patients eligible for UKA who were undergoing TKA)

Stern SH, Becker MW, Insall JN. Unicondylar knee arthroplasty. Anevaluation of selection criteria. Clin Orthop. 1993 Jan; (286): 143-8.


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8%19/250

(Patients eligible for UKA who were undergoing TKA)

Sculco, TP. Orthopaedic Crossfirecan we justify unicondylar arthroplasty as a temporizing procedure? Inopposition. J Arthroplasty. 2002


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UKA: Market Share of Knee

Arthroplasty

North America: 25% market share

Bourne RB. Reevaluating the unicondylar knee arthroplasty. Orthopaedics. 2001Sep;24(9):885-86.


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Prosthesis

EIUS (Osteonics)

Marmor (Smith&Nephew)

Oxford (Biomet)

PCA (Osteonics)

St Georg (Link)

Repicci (Repicci)


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Metal-backed tibial componentsDeshmukh RV, Scott RD. Unicompartmental knee arthroplasty: Long-term results. Clin Orthop

Rel Res 2001 Nov; 393:272-278.

Advantages

? Improved fixation

Disadvantages

Decreased poly thickness

or increased boneresection


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Meniscal-bearing designDeshmukh RV, Scott RD. Unicompartmental knee arthroplasty: Long-term results.

Clin Orthop Rel Res 2001 Nov; 393:272-278

Advantages

? Less loosening

Disadvantages

Technically demanding


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Problems

Aseptic loosening (Tibial componentfixation)

Polyethylene wear

Progression of arthritis

Poor patient selection

Patellofemoral disease

Insall J, Aglietti. A five to seven-year follow-up of unicondylar arthroplasty. J BoneJoint Surg Am. 1980 Dec; 62(8):1329-37.


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Polyethylene wear

Thin tibial polyethylene

Polyethylene gamma-irradiated in air

Polyethylene fusion defects

Undercorrection of deformity

Blunn GW et al. Polyethylene wear in unicondylar knee prosthesis. Acta Orthop Scand 1992 ; 63(3):247-255.

Palmer SH, Morrison PJ, Ross AC. Early catastrophic tibial component wear after unicompartmental knee arthroplasty.Clin Orthop 1998; 350: 143-48.

Engh GA, McAuley JP. Unicondylar arthroplasty: an option for high-demand patients with gonarthrosis. Instr CourseLect. 1999; 48:143-48.


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Why do UKAs fail?

Meta-analysis of 290 UKA followed for an

average of 10 years.

51/290 (18%) revised

Aseptic loosening 22/51 (43%)

Progressive arthritis 17/51 (33%)

Engh GA, McAuley JP. Unicondylar arthroplasty: an option for high-demand patientswith gonarthrosis. Instr Course Lect. 1999; 48:143-48.


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Keys to Success

Patient Selection


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UKA not indicated for:

Inflammatory arthritis

Tricompartmental disease

ACL deficiency with OA

Symptomatic patello-femoraldisease


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What Cannot be Corrected with

UKA?

Varus or valgus

Poor ROM

Flexion contracture (


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UKA best for isolated varus

deformity


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UKA Problems

Instrumentation

Less predictable

than TKA

TKA better limb alignment

and component position

Fisher et al., JOA 2003


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Keys to Success

Proper patient selection Avoid overcorrection

Avoid undercorrection

Minimal bone resection

Good polyethylene

Have revision components available

for conversion to TKA


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Keys to Success




Good polyethylene




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Keys to Success




Good polyethylene




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Keys to Success




Good polyethylene




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May Need to Convert from UKA to

TKA


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Thank You

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