Cognitive impairment influences the risk of reoperation after hip fracture surgery: results of 87,573 operations reported to the Norwegian Hip Fracture Register

Figures & data

Figure 1. Flowchart.

Table 1. Baseline data for patients by cognitive function. Values are frequency (%) unless otherwise specified

Factor	Total	No	Cognitive impairment Uncertain	Yes
Total	87,573	54,859 (63)	8,985 (10)	23,729 (27)
Women	62,751 (72)	39,182 (71)	6,332 (71)	17,237 (73)
Mean age (SD)	83.2 (7.5)	82.0 (7.8)	84.8 (7.0)	85.5 (6.4)
Age group
65–74	12,611 (14)	10,388 (19)	793 (8.8)	1,430 (6.0)
75–79	12,837 (15)	9,120 (17)	1,099 (12)	2,618 (11)
80–84	20,309 (23)	12,727 (23)	2,028 (23)	5,554 (23)
85–89	23,494 (27)	13,247 (24)	2,754 (31)	7,493 (32)
≥ 90	18,322 (21)	9,377 (17)	2,311 (26)	6,634 (28)
ASA class
ASA 1 + 2	32,293 (37)	24,298 (44)	2,485 (28)	5,510 (23)
ASA 3 + 4	55,280 (63)	30,561 (56)	6,500 (72)	18,219 (77)
Fracture type
Undisplaced FNF	12,782 (15)	8,166 (15)	1,223 (14)	3,393 (14)
Displaced FNF	37,006 (42)	22,978 (42)	3,780 (42)	10,248 (43)
Basocervical FNF	3,112 (3.6)	1,918 (3.5)	328 (3.7)	866 (3.6)
Trochanteric A1 ^a	14,768 (17)	9,168 (17)	1,549 (17)	4,051 (17)
Trochanteric A2 ^a	14,012 (16)	8,743 (16)	1,512 (17)	3,757 (16)
Trochanteric A3 ^a	1,439 (1.6)	931 (1.7)	143 (1.6)	365 (1.5)
Subtrochanteric	4,454 (5.1)	2,955 (5.4)	450 (5.0)	1,049 (4.4)
Primary operation
Screw osteosynthesis	16,938 (19)	10,483 (19)	1,707 (19)	4,748 (20)
Hemiarthroplasty	32,667 (37)	20,522 (37)	3,284 (37)	8,861 (37)
Sliding hip screw	27,161 (31)	16,956 (31)	2,827 (31)	7,378 (31)
Short IM nail	7,265 (8.3)	4,529 (8.3)	815 (9.1)	1,921 (8.1)
Long IM nail	3,542 (4.0)	2,369 (4.3)	352 (3.9)	821 (3.5)
Surgical approach
Anterior/anterolateral	2,495 (7.6)	1,604 (7.8)	254 (7.7)	637 (7.2)
Lateral	26,401 (81)	16,596 (81)	2,680 (82)	7,125 (80)
Posterior	3,286 (10)	2,008 (9,8)	308 (9.4)	970 (11)
Other/missing data	485 (1.5)	314 (1.5)	42 (1.3)	129 (1.4)
Fixation of HA
Cemented	24,278 (74)	15,353 (75)	2,408 (73)	6,517 (74)
Uncemented	7,851 (24)	4,854 (24)	804 (25)	2,193 (25)
Missing data	538 (1.6)	315 (1.5)	72 (2.2)	151 (1.7)

FNF = femoral neck fracture, IM = intramedullary, HA = hemiarthroplasty.

a AO/OTA classification.

Table 2. Number of reoperations and risk of reoperation after hip fracture surgery by cognitive function using Cox regression model and Fine and Gray model with adjustments for age, sex, ASA classification, fracture type, and treatment

Cognitive impairment	Total n	Reoperation n (%)	Cox regression Hazard Rate ratio (95% CI)	Fine and Gray Hazard Rate ratio (95% CI)
Total	87,573	6,568 (7.5)
No	54,859	4,860 (8.9)	1 Reference	1 Reference
Uncertain	8,985	598 (6.7)	0.91 (0.83–0.99)	0.91 (0.84–0.99)
Yes	23,729	1,110 (4.7)	0.71 (0.66–0.76)	0.69 (0.65–0.74)
Hemiarthroplasty	32,667	1,425 (4.4)
No	20,522	873 (4.3)	1 Reference	1 Reference
Uncertain	3,284	169 (5.1)	1.3 (1.1–1.6)	1.3 (1.1–1.6)
Yes	8,861	383 (4.3)	1.2 (1.1–1.4)	1.2 (1.0–1.3)
Osteosynthesis	54,906	5,143 (9.4)
No	34,337	3,987 (11)	1 Reference	1 Reference
Uncertain	5,701	429 (7.5)	0.81 (0.73–0.89)	0.85 (0.77–0.94)
Yes	14,868	727 (4.9)	0.58 (0.53–0.63)	0.62 (0.57–0.67)

Table 3. Reasons for reoperation after hemiarthroplasty and osteosynthesis. Reoperations appear in the order of our hierarchy. Values are frequency (%)

Factor	Total	No	Cognitive impairment Uncertain	Yes
All reoperations	6,568 (7.5)	4,860 (8.9)	598 (6.7)	1,110 (4.7)
Reoperation after hemiarthroplasty	1,425 (4.4)	873 (4.4)	169 (5.1)	383 (4.3)
Infection	672 (2.1)	416 (2.0)	81 (2.5)	175 (2.0)
Periprosthetic fracture	151 (0.5)	90 (0.4)	17 (0.5)	44 (0.5)
Dislocation of prosthesis	395 (1.2)	206 (1.0)	55 (1.7)	134 (1.5)
Loosening of hemiarthroplasty	18 (0.1)	17 (0.1)	0 (0.0)	1 (0.0)
Sequelae of femoral neck fracture ^a	31 (0.1)	24 (0.1)	2 (0.1)	5 (0.1)
Other reason	158 (0.5)	120 (0.5)	14 (0.4)	24 (0.3)
Reoperation after osteosynthesis	5,143 (9.4)	3,987 (12)	429 (7.5)	727 (4.9)
Infection	225 (0.4)	136 (0.4)	29 (0.5)	60 (0.4)
Peri-implant fracture	363 (0.7)	247 (0.7)	34 (0.6)	82 (0.6)
Avascular necrosis	346 (0.6)	248 (0.7)	29 (0.5)	69 (0.5)
Osteosynthesis failure	1,541 (2.8)	1022 (3.0)	172 (3.0)	320 (2.2)
Cut-out	142 (0.3)	107 (0.3)	12 (0.2)	23 (0.2)
Non-union	276 (0.5)	212 (0.6)	27 (0.5)	37 (0.2)
Sequelae of proximal femoral fracture ^a	1,744 (3.2)	1,568 (4.6)	96 (1.7)	80 (0.5)
Local pain due to osteosynthesis material	360 (0.7)	318 (0.9)	15 (0.3)	27 (0.2)
Other reason	173 (0.3)	129 (0.4)	15 (0.3)	29 (0.2)

a Reoperation with total hip arthroplasty reported to the Norwegian Arthroplasty Register.