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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Metal ion levels post primary unilateral total knee arthroplasty
Scientific title
Do the patients with well functioning total knee replacement have normal blood metal ion levels compare to normal population?
Secondary ID [1] 283392 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
blood metal ion levels after total knee replacement in the minimum period of one year. 290289 0
Condition category
Condition code
Surgery 290683 290683 0 0
Other surgery
Blood 290698 290698 0 0
Other blood disorders
Musculoskeletal 290699 290699 0 0
Other muscular and skeletal disorders

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Whole blood Chromium and serum Cobalt levels were measured in 22 patients , one year after primary total knee arthroplasty,two types of prosthesis were used,11 patients had triathlon knee system and 11 patients had ACS knee system.
Intervention code [1] 288118 0
Not applicable
Comparator / control treatment
not applicable
Control group

Primary outcome [1] 290702 0
metal ion concentration at one year after surgery

Whole blood levels of Chromium and plasma levels of Cobalt were measured. The primary endpoint was metal ion concentration at one year after surgery.
Blood samples were analysed for Cobalt and Chromium levels by Sullivan Nicolaides Pathology, Queensland. Samples were collected from patients into EDTA trace element vacutainers (Becton Dickinson, Franklin Lakes, NJ) using a stainless steel needle at a collection center and transported to the laboratory at ambient temperature for analysis.
Whole blood Chromium was analysed initially, followed by plasma Cobalt levels. Samples were diluted 1 in 20 with diluent and distilled water using a Starlet Robot (Hamilton Robotics, Reno, NV) by directly sampling from the barcoded EDTA trace element tube after thorough mixing. The diluted samples were vortexed and transferred to an Agilent 7500CE inductively coupled plasma mass spectrometer (ICPMS) equipped with Octopole reaction cells (Agilent Technologies, Santa Clara, CA) for analysis. Helium gas was used in the reaction cell for both Chromium and Cobalt analysis to reduce interference from polyatomic species formed in the plasma. The ICPMS counts for each analyte were processed using the Agilent 7500CE software. A calibration graph was constructed using the counts obtained from the ICPMS expressed as a ratio to the internal standard counts for each analytical run and specimen type. Quality control samples were run every 20 samples and their acceptability was checked.
The results were calculated from the calibration graphs, and downloaded to the laboratory computer for authorization. Sullivan Nicolaides Pathology defined levels of <20 nmol/L for Cobalt and 10-100 nmol/L for Chromium as normal for an Australian population using the method of testing mentioned above
Timepoint [1] 290702 0
one year after surgery
Secondary outcome [1] 305069 0
comparison of blood metal ion levels between cemented and uncemented prosthesis,we compared the results from above mentioned methods between these two groups of patients
Timepoint [1] 305069 0
one year after surgery

Key inclusion criteria
1. Minimum one year post primary unilateral total knee arthroplasty with no other metal implants
2. Well-functioning knee based on clinical findings; including pain, range of movement and stability of the knee. Active patients with no pain, no limited rang of movement, mobility without any walking aids and stable knee in clinical assessment were included in this study.
3. No clinical signs or symptoms of infection
4. No radiographic signs of loosening
Minimum age
58 Years
Maximum age
84 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Patients with prosthesis or metal work elsewhere in the body, systemic disease affecting metal metabolism, renal impairment (including chronic renal failure with eGFR < 30) or chronic/occupational exposure to metal ions were excluded from this study.

Study design
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 1587 0
The Prince Charles Hospital - Chermside

Funding & Sponsors
Funding source category [1] 288115 0
Self funded/Unfunded
Name [1] 288115 0
Address [1] 288115 0
Country [1] 288115 0
Primary sponsor type
prince charles hospital
Rode Rd Chermside QLD 4032
Secondary sponsor category [1] 286836 0
Name [1] 286836 0
Address [1] 286836 0
Country [1] 286836 0

Ethics approval
Ethics application status

Brief summary
BACKGROUND: Metal ion release from metal implants through the processes of mechanical wear and corrosion has been one of the main concerns post total joint arthroplasty. However, there have been very few studies to show metal ion exposure post total knee implants.
AIM: The aim of this study was to investigate whether blood metal ion levels are raised in patients with well-functioning unilateral primary total knee arthroplasty one year after surgery.
METHODS: Whole blood Chromium and serum Cobalt levels were measured in 22 patients following primary total knee arthroplasty. Eleven patients had the cemented triathlon knee system and 11 patients had uncemented ACS knee system with multilayer coatings.
RESULTS: Whole bloods Chromium and serum Cobalt levels were within the normal range.
CONCLUSION: On the basis of our results, there does not appear to be any significant rise in blood metal ion levels following well-functioning total knee arthroplasty in one-year post surgery.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 43622 0
Dr Amin Masoumiganjgah
Address 43622 0
prince charles hospital
Rode Rd Chermside QLD 4032
Country 43622 0
Phone 43622 0
Fax 43622 0
Email 43622 0
Contact person for public queries
Name 43623 0
Prof Ross Crawford
Address 43623 0
Orthopaedic Research Unit
Institute of Health and Biomedical Innovation,
Queensland University of Technology,
The Prince Charles Hospital
Rode Road, Chermside
Queensland 4032
Country 43623 0
Phone 43623 0
+61 7 3139 4481
Fax 43623 0
Email 43623 0
Contact person for scientific queries
Name 43624 0
Dr Sarah L Whitehouse
Address 43624 0
Queensland University of Technology,
The Prince Charles Hospital
Rode Road, Chermside
Queensland 4032
Country 43624 0
Phone 43624 0
+61 7 3139 4481
Fax 43624 0
Email 43624 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary