Survival of 11,390 Continuum cups in primary total hip arthroplasty based on data from the Finnish Arthroplasty Register

Figures & data

Table 1. Acetabular cups included in the study

Cup design	n (%)
Continuum (ZimmerBiomet, Warsaw, IN, USA)	11,390 (27)
Reference group	30,372 (73)
•Exceed (ZimmerBiomet, Warsaw, IN, USA)	1,550 (4)
•G7 (ZimmerBiomet, Warsaw, IN, USA)	1,121 (3)
•Pinnacle (DePuy, Warsaw, IN, USA)	14,844 (36)
•R3 (Smith & Nephew, Andover, MA, USA)	7,289 (18)
•Trident (shell) (Stryker, Mahwah, NJ, USA)	4,279 (10
•Vision Ringloc (ZimmerBiomet, Warsaw, IN, USA)	1,280 (3)

Table 3. Demographic data of the time period after data content revision in the Finnish Arthroplasty Register starting May 15, 2014. Values are frequency (%) unless stated otherwise

Data	Continuum group	Reference group
Mean age (SD)	67 (11)	66 (11)
BMI (SD)	28 (5)	28 (5)
Male sex	3,609 (42)	7,547 (46)
Diagnosis
•Primary osteoarthritis	7,324 (85)	13,852 (85)
•Rheumatoid arthritis	137 (2)	195 (1)
•Other ^a	1,113 (13)	2,278 (14)
Femoral head size of prosthesis
•28 mm	29 (0.3)	107 (1)
•32 mm	1,832 (21)	3,369 (21)
•36 mm	6,713 (78)	12,849 (79)
Status at end of follow-up
•Not revised	8,202 (96)	15,792 (97)
•Revised	372 (4)	533 (3)
Liner material
•Ceramic	619 (7)	2,249 (14)
•Highly cross-linked polyethylene	7,955 (93)	14,041 (86)
Elevated liner
•No	4,385 (55)	8,648 (62)
•Yes	3,570 (45)	5,393 (38)
Approach
•Posterior	6,654 (78)	12,884 (81)
•Anterolateral (modified Hardinge)	1,667 (20)	2,864 (18)
•Anterior (Watson-Jones)	15 (0.2)	11 (0.1)
•Anterior (Smith-Peterson)	143 (2)	137 (1)
Trochanteric osteotomy performed	1 (0.01)	1 (0.01)
ASA class
•1	1,281 (15)	2,163 (14)
•2	4,132 (49)	8,260 (52)
•3	2,992 (35)	5,308 (33)
•4	104 (1)	189 (1)
Femoral stem fixation
•Uncemented	5,502 (65)	13,209 (81)
•Cemented	3,030 (36)	3,057 (19)

a Fractures (5% Continuum group vs. 4% control group), avascular necrosis (3% vs. 3%), osteoarthritis due to hip dysplasia (2% vs. 2%), tumors (1% vs. 1%), congenital hip dislocation (0.5% vs. 0.3%), inflammatory arthritis (0.3% vs. 0.4%), Legg–Perthes–Calve disease (0.3% vs. 0.2%), femoral head epiphyseolysis (0.2% vs. 0.1%), status post purulent arthritis (0.1% vs. 0%).

Table 4. Indication for revision prior to data content revision (May 15, 2014) of the Finnish Register. Values are frequency (%)

Main reason for revision^a	Continuum group	Reference group
Aseptic loosening
•Cup and stem	0 (0)	2 (1)
•Cup	2 (4)	15 (5)
•Stem	3 (6)	17 (5)
Infection	7 (13)	56 (18)
Dislocation	21 (39)	88 (28)
Component malposition	3 (6)	31 (10)
Fracture	13 (24)	72 (23)
Component breakage	0 (	4 (1)
Other	5 (9)	28 (9)

a No data available concerning indication for revision from 83 revisions.

Table 5. Indication for revision after new indications for revision were added at the data content revision (May 15, 2014) of the Finnish Register. Values are frequency (%)

Main reason for revision^a	Continuum group	Reference group
Aseptic loosening
•Cup	5 (1)	10 (2)
•Stem	15 (4)	26 (4)
Osteolysis
•Cup	2 (1)	8 (1)
•Stem	1 (0.3)	11 (2)
Liner wear	0 (0)	2 (2)
Component breakage
•Cup	0 (0)	1 (0.2)
•Liner	1 (0.3)	11 (2)
•Head	1 (0.3)	1 (0.2)
•Modular neck	0 (0)	1 (0.2)
Infection	100 (26)	194 (30)
Dislocation	132 (34)	153 (24)
Component malposition
•Cup	12 (3)	23 (4)
•Stem	1 (0.3)	14 (2)
Periprosthetic fracture
•Acetabulum	6 (2)	2 (0.3)
•Femur	73 (19)	105 (17)
Adverse reaction to metal debris	2 (1)	5 (1)
Squeaking	2 (1)	5 (1)
Unexplained pain	10 (3)	32 (5)
Leg length discrepancy repair	4 (1)	10 (2)
Other	17 (4)	24 (4)

a No data available concerning indication for revision from 83 revisions.

Figure 1. Kaplan–Meier survival for Continuum group and reference group with revision for any reason as the endpoint. 95% CI levels presented in blue and red.

Figure 2. Kaplan–Meier survival for Continuum group and reference group with revision for infection as endpoint. 95% CI levels presented in blue and red.

Figure 3. Kaplan–Meier survival for Continuum group and reference group with revision for dislocation as endpoint. 95% CI levels presented in blue and red.

Figure 4. Kaplan–Meier survival by subgroup analysis of Continuum THA with or without elevated liner. Endpoint: revision for dislocations. 95% CI levels presented in blue and red.