Serum Metal Ion Concentrations in Paediatric Patients following Total Knee Arthroplasty Using Megaprostheses

Table 1

Demographic data of the study population and mean metal ion levels in μg/L (range) in the different prosthesis groups. The value indicates differences between several implant groups compared to the fixed hinge group. Furthermore, correlations between Co and Cr levels in the implant groups as well as metal ion concentrations and follow-up are shown (THA: total hip arthroplasty; RHK: rotating hinge knee arthroplasty; yr/yrs: year/years; mths: months; FU: follow-up).

	Fixed hinge prostheses	Preoperative THA	MoM THA 1 yr	MoM THA 2 yrs	Standard RHK	Megaprostheses RHK
Mean age (yrs)	14 (10 to 23)	52 (40 to 61)	n.a.	n.a.	73 (60 to 81)	49 (15 to 83)
Sex ratio (m : f)	9 : 2	17 : 15	17 : 15	17 : 15	4 : 4	12 : 5
Mean follow-up (mths)	108 (67 to 163)	n.a.	12 (12 to 12)	24 (24 to 24)	37 (15 to 62)	34 (9 to 67)
Co serum (μg/L)	4.7 (0.4 to 12.8)	0.3 (0 to 5.4)	6.0 (0 to 58.5)	9.3 (0.3 to 78.2)	0.3 (0 to 0.7)	7.5 (0 to 47.0)
Cr serum (μg/L)	4.01 (1.48 to 8.91)	0.68 (0.07 to 7.53)	5.86 (1.11 to 26.56)	8.31 (0.71 to 51.98)	0.33 (0.06 to 0.95)	2.98 (0.12 to 24.90)
P value Co/Cr	—	<0.001/<0.001	0.852/0.731	0.501/0.235	0.002/<0.001	0.312/0.002
Correlation Co : Cr	0.742 ()	0.945 ()	0.869 ()	0.967 ()	0.764 ()	0.945 ()
Correlation Co : FU	0.240 ()	x	x	x	0.099 ()	0.300 ()
Correlation Cr : FU	0.137 ()	x	x	x	0.007 ()	0.373 ()