ASA class is associated with early revision and reoperation after total hip arthroplasty: an analysis of the Geneva and Swedish Hip Arthroplasty Registries

Figures & data

Table 1. Preoperative patient characteristics by ASA class

	GAR				SHAR
	ASA I	ASA II	ASA III–IV	Total	ASA I	ASA II	ASA III–IV	Total
	n = 481	n = 3,496	n = 1,342	n = 5,319	n = 29,280	n = 72,857	n = 20,104	n = 122,241
Women, n (%)	259 (54)	2,106 (60)	767 (57)	3,132 (59)	16,112 (55)	41,460 (59)	9,885 (53)	67,149 (57)
Age (mean, SD)	60.1 (12.3)	68.8 (11.7)	76.1 (10.1)	69.9 (12.2)	62.5 (10.7)	69.2 (9.7)	72.9 (9.8)	68.2 (10.5)
Age categories, n (%)
< 55	150 (31)	393 (11)	42 (3.1)	585 (11)	6,325 (22)	5,152 (7.1)	863 (4.3)	12,340 (10)
55–64	127 (26)	667 (19)	109 (8.1)	903 (17)	9,679 (33)	15,756 (22)	2,701 (13)	28,136 (23)
65–74	152 (32)	1,226 (35)	357 (27)	1,735 (33)	9,766 (33)	29,660 (41)	6,999 (35)	46,425 (38)
75–84	49 (10)	1,024 (29)	550 (41)	1,623 (31)	3,225 (11)	19,423 (27)	7,648 (38)	30,296 (25)
≥ 85	3 (0.6)	186 (5.3)	284 (21)	473 (8.9)	285 (1.0)	2,866 (3.9)	1,893 (9.4)	5,044 (4.1)
BMI (mean, SD)	24.8 (3.3)	26.8 (4.7)	27.3 (5.6)	26.8 (4.9)	26.1 (3.8)	27.4 (4.4)	28.7 (5.6)	27.3 (4.6)
BMI categories, n (%)
< 18.5	13 (2.7)	63 (1.8)	43 (3.3)	119 (2.3)	195 (0.6)	531 (0.7)	240 (1.2)	966 (0.8)
18.5–24	245 (51)	1,280 (37)	437 (33)	1,962 (37)	11,405 (38)	20,933 (29)	5,008 (26)	37,346 (31)
25–29	193 (40)	1,303 (38)	441 (33)	1,937 (37)	12,868 (43)	31,374 (44)	6,955 (36)	51,197 (43)
30–34	27 (5.6)	642 (19)	288 (22)	957 (18)	3476 (12)	14,512 (20)	4,520 (23)	22,508 (19)
35–39	2 (0.4)	156 (4.5)	85 (6.4)	243 (4.6)	416 (1.3)	3,234 (4.5)	2,115 (11)	5,765 (4.8)
≥ 40	0 (0.0)	26 (0.7)	27 (2.0)	53 (1.0)	66 (0.2)	529 (0.7)	629 (3.2)	1,224 (1.0)
Missing data	1	26	21	48	854	1,744	637	3,235
Diagnosis, n (%)
Primary OA	375 (78)	2,817 (81)	1,007 (75)	4,199 (79)	26,644 (91)	67,221 (92)	17,666 (88)	111,531 (92)
Secondary OA	106 (22)	679 (19)	335 (25)	1,120 (21)	2,636 (9.0)	5,636 (7.7)	2,438 (12)	10,710 (8.8)

Table 2. Incidence of revision and other reoperation within 5 years of primary THA by ASA score

	Total number	Revision Cumulative incidence (CI)		Total number	Other reoperation Cumulative incidence (CI)
	(%)	3 months	5 years	(%)	3 months	5 years
Geneva
All patients	126 (2.4)	1.1 (0.8–1.4)	2.6 (2.1–3.0)	95 (1.8)	0.7 (0.5–0.9)	1.9 (1.5–2.3)
ASA I	10 (2.1)	0.6 (0.0–1.3)	2.3 (0.9–3.8)	9 (1.9)	0.4 (0.0–1.0)	2.0 (0.7–3.4)
ASA II	73 (2.1)	0.7 (0.4–1.0)	2.3 (1.8–2.8)	58 (1.7)	0.7 (0.4–0.9)	1.8 (1.3–2.2)
ASA III–IV	43 (3.2)	2.3 (1.5–3.1)	3.3 (2.3–4.3)	28 (2.1)	0.9 (0.0 –1.4)	2.2 (1.4–3.0)
Sweden
All patients	2,353 (1.9)	0.9 (0.8–0.9)	2.3 (2.2–2.4)	878 (0.7)	0.4 (0.4–0.4)	0.8 (0.8–0.9)
ASA I	444 (1.5)	0.5 (0.4–0.6)	1.9 (1.7–2.1)	145 (0.5)	0.2 (0.2–0.3)	0.6 (0.5–0.7)
ASA II	1,364 (1.9)	0.8 (0.7–0.9)	2.3 (2.2–2.4)	522 (0.7)	0.4 (0.3–0.4)	0.8 (0.8–0.9)
ASA III–IV	545 (2.7)	1.6 (1.4–1.7)	3.3 (3.0–3.6)	211 (1.0)	0.7 (0.6–0.8)	1.2 (1.0–1.4)

Table 3. Associations with the risk of revision (time-invariant HR unless specified)

	GAR cohort	SHAR cohort
Model	HR (CI)	HR (CI)
Univariable model
ASA I	1 (ref)	1 (ref)
ASA II	1.0 (0.5–2.0)	1.6 (1.4–2.0) ^a,f
		1.1 (0.9–1.3) ^b,f
ASA III–IV	3.4 (1.6–7.4) ^a,c	3.2 (2.6–3.9) ^a,f
	0.7 (0.3–1.7) ^b,c	1.3 (1.1–1.6) ^b,f
Multivariable model
ASA I	1 (ref)	1 (ref)
ASA II	1.0 (0.5–1.9)	1.7 (1.4–2.1) ^a,g
		1.2 (1.0–1.3) ^b,g
ASA III–IV	2.7 (1.2–5.9) ^a,d	3.3 (2.6–4.0) ^a,g
	0.7 (0.3–1.7) ^b,d	1.4 (1.1–1.6) ^b,g
Sex
Male	1 (ref)	1 (ref)
Female	0.8 (0.6–1.1)	0.7 (0.6–0.7)
Diagnosis
Primary OA	1 (ref)	1 (ref)
Secondary OA	2.4 (1.7–3.5)	1.4 (1.3–1.6)
BMI
< 35	1 (ref)	1 (ref)
≥ 35	3.7 (2.3–6.0)	2.6 (2.2–3.1) ^a,h
		1.2 (1.0–1.5) ^b,h
Age
< 85 y	1 (ref)	1 (ref)
≥ 85 y	1.6 (0.8–3.3) ^a,e	1.9 (1.5–2.4) ^a,i
	0.2 (0.1–1.7) ^b,e	0.6 (0.4–0.8) ^b,i

^a HR within the first 3 months.

^b HR after 3 months and within 5 years.

^c The change in HR within the first 3 months and after was statistically significant (p < 0.001).

^d The change in HR within the first 3 months and after was statistically significant (p = 0.002).

^e A change in HR within the first 3 months and after was suspected (p = 0.07).

^f The change in HR within the first 3 months and after was statistically significant (ASA II: p < 0.001, ASA III–IV: p < 0.001).

^g The change in HR within the first 3 months and after was statistically significant (ASA II: p < 0.001, ASA III–IV: p < 0.001).

^h The change in HR within the first 3 months and after was statistically significant (p < 0.001).

ⁱ The change in HR within the first 3 months and after was statistically significant (p < 0.001).

Table 4. Associations with the risk of other reoperation (time-invariant HR unless specified)

	GAR cohort	SHAR cohort
Model	HR (CI)	HR (CI)
Univariable model
ASA I	1 (ref)	1 (ref)
ASA II	0.9 (0.5–1.8)	1.8 (1.3–2.4)a^,f
		1.2 (1.0–1.6)b^,f
ASA III–IV	1.2 (0.6–2.5)	3.2 (2.3–4.3)a^,f
		1.6 (1.2–2.1)b^,f
Multivariable model
ASA I	1 (ref)	1 (ref)
ASA II	0.9 (0.4–1.7)	1.7 (1.2–2.2)a^,g
		1.1 (0.9–1.5)b^,g
ASA III–IV	1.1 (0.5–2.4)	2.7 (2.0–3.7)a^,g
		1.4 (1.0–1.8)b^,g
Sex
Male	1 (ref)	1 (ref)
Female	0.8 (0.4–1.6)a^,c	0.6 (0.5–0.8)a^,h
	1.8 (1.0–3.2)b^,c	1.0 (0.8–1.2)b^,h
Diagnosis
Primary OA	1 (ref)	1 (ref)
Secondary OA	3.1 (1.6–6.0)a^,d	1.8 (1.5–2.2)
	0.7 (0.4–1.5)b^,d
BMI
< 35	1 (ref)	1 (ref)
≥ 35	4.5 (1.9–10.3)a^,e	2.6 (1.9–3.4)a^,i
	1.1 (0.4–2.9)b^,e	1.2 (0.8–1.7)b^,i
Age
< 85 y	1 (ref)	1 (ref)
≥ 85 y	0.9 (0.4–2.0)	1.9 (1.4–2.4)

^aHR within the first 3 months.

^bHR after 3 months and within 5 years.

^cA change in HR within the first 3 months and after was suspected (p = 0.08).

^dThe change in HR within the first 3 months and after was statisti-cally significant (p = 0.003).

^eA change in HR within the first 3 months and after was suspected (p = 0.05).

^fThe change in HR within the first 3 months and after was statisti-cally significant (ASA II: p = 0.05, ASA III–IV: p = 0.001).

^gThe change in HR within the first 3 months and after was statisti-cally significant for ASA II (p = 0.05) and close to statistical signifi-cance for ASA III–IV (p = 0.05).

^hThe change in HR within the first 3 months and after was statisti-cally significant (p < 0.001).

ⁱThe change in HR within the first 3 months and after was statisti-cally significant (p = 0.001).

Table 5. Indications for revision and other reoperation within 3 months by ASA grade

	Geneva				Sweden
	ASA I	ASA II	ASA III–IV	Total	ASA I	ASA II	ASA III–IV	Total
Factor	n = 481	n = 3,496	n = 1,342	n = 5,319	n = 29,280	n = 72,857	n = 20,104	n = 122,241
Indications for revision, n (%)
Dislocation	1 (0.2)	5 (0.1)	12 (0.9)	18 (0.3)	30 (0.1)	103 (0.1)	57 (0.3)	190 (0.2)
Infection	1 (0.2)	8 (0.2)	7 (0.5)	16 (0.3)	81 (0.3)	356 (0.5)	195 (1)	632 (0.5)
Periprosthetic fracture	0	6 (0.2)	7 (0.5)	13 (0.2)	24 (0.1)	80 (0.1)	42 (0.2)	146 (0.1)
Aseptic loosening	0	4 (0.1)	3 (0.2)	7 (0.1)	8 (< 0.1)	21 (< 0.1)	8 (< 0.1)	37 (< 0.1)
Implant malposition	0	1 (< 0.1)	1 (0.1)	2 (< 0.1)	3 (< 0.1)	8 (< 0.1)	3 (< 0.1)	14 (< 0.1)
Other ^a	1 (0.2)	1 (< 0.1)	1 (0.1)	3 (0.1)	1 (< 0.1)	2 (< 0.1)	3 (< 0.1)	6 (< 0.1)
Unknown	0	0	0	0	2 (< 0.1)	3 (< 0.1)	0	5 (< 0.1)
Total	3 (0.6)	25 (0.7)	31 (2.3)	59 (1.1)	149 (0.5)	573 (0.8)	308 (1.5)	1,030 (0.8)
Indications for reoperation, n (%)
Infection	1 (0.2)	11 (0.3)	3 (0.2)	15 (0.3)	45 (0.2)	219 (0.3)	106 (0.5)	370 (0.3)
Periprosthetic fracture	0	3 (0.1)	6 (0.4)	9 (0.2)	4 (< 0.1)	16 (< 0.1)	10 (< 0.1)	30 (< 0.1)
Hematoma	1 (0.2)	4 (0.1)	1 (0.1)	6 (0.1)	1 (< 0.1)	9 (< 0.1)	8 (< 0.1)	18 (< 0.1)
Abductor avulsion	0	2 (0.1)	1 (0.1)	3 (0.1)	1 (< 0.1)	1 (< 0.1)	0	2 (< 0.1)
Dislocation	0	0	0	0	3 (< 0.1)	8 (< 0.1)	1 (< 0.1)	12 (< 0.1)
Cement problem	0	0	0	0	1 (< 0.1)	3 (< 0.1)	2 (< 0.1)	6 (< 0.1)
Other ^b	0	3 (0.1)	1 (0.1)	4 (0.1)	2 (< 0.1)	7 (< 0.1)	1 (< 0.1)	10 (< 0.1)
Unknown	0	0	0	0	1 (< 0.1)	3 (< 0.1)	2 (< 0.1)	6 (< 0.1)
Total	2 (0.4)	23 (0.7)	12 (0.9)	37 (0.7)	58 (0.2)	266 (0.4)	130 (0.6)	454 (0.4)

^a Other includes: infection suspected but not confirmed; hematoma; other material left in joint; nerve injury; delayed healing; pain.

^b Other includes: infection suspected but not confirmed; pain; allergy to suture; other material left in joint; aseptic loosening.

Cumulative incidence of revision in (A) GAR and (B) SHAR and cumulative incidence of other reoperation in (C) GAR and (D) SHAR by ASA class (95% CI shown in shading). The association with ASA class was statistically significant in SHAR (p < 0.001 for both revision and other reoperation). In GAR, the p-value was 0.07 for revision but the difference was statistically significant between ASA class III or IV and ASA class I or II (p = 0.02). No association with ASA class was detected in GAR for other reoperation (p = 0.6).