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Patient characteristics

By type of knee prosthesis
By diagnosis

Knee » Patient characteristics » By type of knee prosthesis

TABLE Patient characteristics of all patients with a registered primary knee arthroplasty by type of knee arthroplasty in the Netherlands in 2021

	TKA	UKA	PFA	Total¹
N (%)	21,444 (78)	5,648 (20)	107 (0)	27,217
Mean age (years) (SD)	69.3 (8.9)	65.4 (8.8)	54.6 (9.0)	68.4 (9.0)
Age (years) (%)
<50	1	3	24	2
50-59	13	24	46	16
60-69	34	40	23	35
70-79	40	28	7	37
≥80	12	5	0	10
Gender (%)
Men	38	46	29	39
Women	62	54	71	61
ASA score (%)
I	10	16	30	12
II	65	69	58	64
III-IV	25	15	12	23
Type of hospital (%)
General	76	66	74	74
UMC	1	1	3	1
Private	23	33	23	25
Diagnosis (%)
Osteoarthritis	96	99	94	97
Post-traumatic	2	0	5	1
Rheumatoid arthritis	1	0	1	1
Osteonecrosis	1	1	0	1
Other	0	0	0	0
Charnley-score (%)
A One knee joint affected	38	47	47	40
B1 Both knee joints affected	34	33	29	34
B2 Contralateral knee joint with a total knee prosthesis	24	18	19	23
C Multiple joints affected or chronic disease that affects quality of life	4	2	5	3
Mean Body Mass Index (kg/m²) (SD)	29.4 (4.9)	28.9 (4.4)	28.3 (4.7)	29.3 (4.8)
Body Mass Index (kg/m²) (%)
Underweight (≤18,5)	0	0	2	0
Normal weight (>18,5-25)	19	20	26	19
Overweight (>25-30)	42	44	37	42
Obesity (>30-40)	36	34	34	36
Morbid obesity (>40)	3	1	1	3
Smoking (%)
No	93	93	90	93
Yes	7	7	10	7

¹ Also contains 18 (0.1%) primary knee arthroplasties of which the type of prosthesis was not registered.
TKA: total knee arthroplasty; UKA: unicondylar knee arthropalsty; PFA: patellofemoral knee arthroplasty; General: general hospital; UMC: university medical centre; Private: private hospital; SD: standard deviation.

Knee » Patient characteristics » By diagnosis

TABLE Patient characteristics of all patients with a registered primary knee arthroplasty by type of diagnosis in the Netherlands in 2021

	Osteoarthritis	Post-traumatic	Rheumatoid arthritis	Osteonecrosis	Total¹
N (%)	26,187 (96)	359 (1)	258 (1)	141 (1)	27,217
Mean age (years) (SD)	68.5 (8.9)	62.8 (10.8)	65.3 (11.2)	69.0 (11.7)	68.4 (9.0)
Age (years) (%)
<50	1	9	6	4	2
50-59	15	31	21	11	16
60-69	35	31	33	29	35
70-79	38	22	31	38	37
≥80	11	7	8	18	10
Gender (%)
Men	39	46	25	35	39
Women	61	54	75	65	61
ASA score (%)
I	12	17	3	7	12
II	65	65	67	58	64
III-IV	23	18	30	35	23
Type of hospital (%)
General	74	69	74	74	74
UMC	1	8	5	5	1
Private	25	23	21	21	25
Charnley-score (%)
A One knee joint affected	39	69	19	74	40
B1 Both knee joints affected	34	20	41	18	34
B2 Contralateral knee joint with a total knee prosthesis	23	7	14	7	23
C Multiple joints affected or chronic disease that affects quality of life	3	4	26	2	3
Mean Body Mass Index (kg/m²) (SD)	29.3 (4.8)	28.5 (4.6)	28.1 (4.8)	28.7 (4.6)	29.3 (4.8)
Body Mass Index (kg/m²) (%)
Underweight (≤18,5)	0	0	1	1	0
Normal weight (>18,5-25)	19	25	28	23	19
Overweight (>25-30)	42	45	40	42	42
Obesity (>30-40)	36	28	29	33	36
Morbid obesity (>40)	3	3	2	1	3
Smoking (%)
No	93	89	92	94	93
Yes	7	11	8	6	7

Please note: In 2021, 121 (0.4%) patients had a primary knee arthroplasty after a diagnosis that is not listed in the table. Of 151 (0.6%) primary knee arthroplasties the diagnosis was not registered.
General: general hospital; UMC: university medical centre; Private: private hospital; SD: standard deviation.