2008/07/23

A. Grubl et alJBJS (B), Aug 2006,

Polyethylene debris, wear particles peri-prosthetic osteolysis long-term failure

Change bearing surfaces ceramic / metal

Co-Cr-Mo

Al2O3 ( 氧化鋁 )

THR without cement in 100 consecutive patients

50 patients metal-on-metal articulation,

50 patients ceramic-on-polyethylene bearing

Metal particles: cobalt and chromium ions ↑

P Sauvé; J Mountney; T Khan; J De Beer; et al

Journal of Bone and Joint Surgery; May 2007; 89,

cobalt and chromium: 3~5 X ↑ Source of metal ions Metal-on-

metal articulations 3 patients: revision with metal-on-PE

the levels of metal ions were within the normal range

Ring and other metal-on-metal THRs: early failure some into fourth decade polar bearing with sufficient clearance good orientation of the component avoiding

impingement No polyethylene, no subsequent

osteolysis Wear rates between 40 and 100 times

lower than those of metal-on-PE bearing surfaces !!

Cobalt Chromosomal abnormalities potential for

malignant change Reduce osteoblastic activity Inhibit the production of type-I collagen and

osteocalcin and alkaline phosphatase activity toxic to cultured human synovial fibroblasts Peripheral blood CD+ T-cell counts are

significantly reduced Hypersensitivity

Women of child-bearing age cobalt ions cross the placenta !!

Aluminium: Various neurological disorders

Alzheimer’s disease Osteomalacia

Prospective, randomized Clinical trial Ceramic-on-ceramic / metal-on-metal Serum aluminium / cobalt levels

Including: Unilateral primary osteoarthritis Avascular necrosis of the hip

Excluding: Rheumatoid arthritis Renal malfunction Other metal implants

Nov, 2000 to Feb, 2002 28 patients Randomly to receive ceramic or

metal bearing

26 OA 2 AVN 18 Female 10 man Mean age 62.2 years old. (32 to 81) Mean BMI 28.1 (19.6 to 37.3)

Ceramic on ceramic

Metal on metal

Patient No. 15 13

Female : male

8 : 7 10 : 3

Mean age 58.2 (32 to 81)66.8 (56 to 78)

All the same prosthesis except bearing surface Ti-Al-Nb alloy (CSF-Gamma, Zimmer)

Ceramic / metal inlay Ceramic inserts: Al2O3

Metal inserts: Co-Cr-Mo

Transgluteal approach (lateral) supine Intra-operation X-ray:

Cup inclination ≦ 45 degree

Blood: Needles: no cobalt Glass tube Pre-OP and 12 months after OP

Serum Al and Co level 5100-ZL atomic absorption

spectrometer (Perkin Elmer, Shelton, Connecticut)

Wavelengths: 309.3 and 242.5 nm Lower limitation:

Al: 0.5 μg/l; (define 0.25) Co: 0.3 μg/l; (define 0.15)

Functional result Harris hip score University of California at Los Angeles

activity score (UCLA)

Pain Limp Support Distanc

e Sitting Enter

public transportation

Stairs Put on

shoes Deformi

ty ROM

SAS P value ≦ 0.05: statistically

significant Sign test for paired data

Ceramic on ceramic

Metal on metal

Pre-OP Pre-OP

Post-OP Post-OP

Aluminium 1.3 (0.25 to 8.4)1.9 (0.25 to 4.4)

1.1 (0.25 to 2.3) P =10.9 (0.25 to 3.9)

P = 0.012

Cobalt < 0.3 < 0.3

0.4 (0.15 to 0.7)P= 0.508

1.4 (0.5 to 10.5)

P < 0.001

Harris hip score

58.4 (24.4 to 82.3)

50.4 (15.1 to 71.4)

86.6 (41.5 to 100)

85.1 (61.1 to 100)

UCLA 7 /10, 90% satisfied or very satisfied

Mean inclination of cup

44.2° (34° to 54°)

Cobalt and chromium ion ↑: metal on metal THR

Aluminium: no increasing in metal-on-metal THR, but ceramic-on-ceramic ??

Ceramic-on-ceramic bearings: Low wear rate High biocompatibility

No evidence of systemic release of aluminium in the ceramic-on-ceramic or metal-on-metal groups

Serum cobalt ↑in metal-on-metal group

In vitro comparison of Metasul metal-on-metal and Cerasul ceramic-on-ceramic bearing

Stanmore Mk-III hip simulator 2~5 X 106 cycles Similar abrasive wear behavior

Prospective, randomised study 514 patients, Alumina ceramic bearing vs. Co-Cr

metal-on-PE bearing Mid-term result: no significant

difference in clinical performance

In vivo Ceramic-on-ceramic bearings are

NOT associated with elevated levels of serum aluminium.

Cobalt level at one year was significant increasing in metal on metal group