Unicompartmental Arthroplasty

John GoodfellowNuffield Orthopaedic

Centre, Oxford

AnteromedialOsteoarthritis

(30% of OA knees)

Fixed Bearing UKR

• Wear inescapable Incongruous

• Thin polyethylene• Catastrophic failure

Meniscal function

Phase 1 1976

Polyethylene Wear

• Average penetration rate

0.03mm per year• Average time for 1mm

penetration 33 years

10 year retrieval

Indications

Criteria

• Antero-medial OA• Intact ACL• Full thickness lateral• Correctable varus• FFD less than 15°• 1 in 3 OA knees

Not Contraindications

• Patello-femoral joint• Chondrocalcinosis• Obesity• Age• Activity

0%

20%

40%

60%

80%

100%

0 5 10

Time post operation (years)

Su

rviv

al

UKR - Designer’s series

• 10 year survival 98%• Murray et al JBJS 1998

0

20

40

60

80

100

0 5 10 15 20Years

Sur

viva

l %Svard & Price (AAOS 2006)

20 yr survival 92% CI 15.1

10 yr 90% Good or Excellent HSS (n=187)

Minimally Invasive Surgery

MIS results – Early Recovery• Less Bleeding

• Lower Morbidity

• Shorter Hospital Stay

• Quicker Flexion

• Time to recovery:

3x faster than TKR (p<0.001)

2x faster than open UKR (p<0.001)

Functional recovery

0%

50%

100%

150%

TKR Open Minimal

Unilateral

Bilateral

National Registers

• Measured by revision, failure rate of UKR at 10yrs is approx x 2 TKR

• National failure rates of UKR are higher than reports from Specialist Centres

• Failure rates of UKR vary with the experience of the surgeon

Dependence on Surgical Experience(Roberttson et al)

Instructional Courses

• To diminish the ‘learning curve’

• To teach indications

• To improve surgical technique