Patient injuries in primary total hip replacement

Figures & data

Table 1. Compensation criteria

Main criteria^a:	Compensatable if:
Treatment injury	An experienced clinician would have acted differently and thus avoided the severe harm and/or injury to the patient.
Infection injury	Based on patient’s comorbidities and medications, the preoperative infection risk is below 2% and the consequences for the patient are sufficiently severe.
Unreasonable injury	A severe injury that led to permanent harm or death and was unpredictable judging by her illness and health status in general and the healthcare or medical care given.
Specific treatment injury events:	Compensatable if^b:
Postoperative infection	The patient has suffered a DSSI that has led to severe consequences e.g. (1–) 2 subsequent reoperations/revisions or permanent removal of the implant (Girdlestone procedure) and prolonged aftercare.
Cup or stem malposition	Component malpositioning leading to significant clinical symptoms/adverse event leading to reoperation(s). Could have been avoided with more careful surgical execution.
Cup or stem instability	Component instability could have been avoided with more careful surgical execution, and has led to a reoperation.
Leg length discrepancy	Unplanned postoperative leg length discrepancy of more than 1.5 cm.
Fracture	The fracture has been overlooked during the operation or the osteosynthesis has been inadequate.
Nerve or vascular injury	Inability to protect the surrounding nerves or vasculature during the operation (e.g. documented direct injury, inability to locate and protect the ischias nerve when using posterolateral approach, unintentional leg length discrepancy leading to paresis, severe vascular injury).
Delay in treatment	A delay that has led to the severe harm/injury to the patient.
Insufficient diagnostics	Some significant clinical or radiological findings have been overlooked or misdiagnosed, leading to severe harm/injury to the patient.

a Defined in detail in the Patient Injury Act (Järvelin et al. 2012).

b Each claim is evaluated individually; thus, the criteria here are directional.

DSSI: deep surgical site infection.

Table 2. Patient and operation characteristics (expressed as %)

			Age		Sex		Diagnosis		Operation		Hospital volume
		n	≥ 65	< 65	Men	Women	POA^a	Other	NFB30^b	Other	≥ 400	< 400
A	Non-claimants	42,579	58	42	44	56	86	14	52	48	33	67
	All claimants	563	52	48	43	57	86	14	58	42	21	79
	p-value		0.005^c	0.6		0.6		0.005^c	< 0.001^c
B	Non-claimants	43,021	58	42	44	56	86	14	52	48	33	67
	Infections	121	57	43	61	39	89	11	54	46	23	77
	p-value		0.9		< 0.001^c	0.4		0.8		0.03^c
C	Non-claimants	42,700	58	42	44	56	86	14	52	48	33	67
	Treatment injuries	442	47	53	38	62	85	15	60	40	21	79
	p-value		< 0.001^c	0.01^c	0.3		0.002^c	0.001^c
D	Denied	313	50	50	41	59	84	16	58	42	24	76
	Compensated	250	48	52	45	55	87	13	58	42	18	82
	p-value		0.2		0.3		0.3		1.0		0.05
E	< 400 (group 1–3)	443	52	48	44	56	88	12	58	42	…	…
	≥ 400 (group 4)	120	50	50	40	60	76	24	58	42	…	…
	p-value		0.4		0.4	< 0.001^c	0.5

The patient and operation characteristics of total hip replacement (THR) recipients in Finland between 2005 and 2010 are presented as percentages of all in the group. Patients were characterized based on age, sex, and diagnosis. Operations were characterized based on operation type and hospital volume. Lines A, B, and C show the comparison of variables associated with claim filing among all claimants, infection claimants, and treatment injury claimants compared to all THR recipients who did not file a claim (“non-claimants”). Rows marked D show a comparison of the characteristics of denied and compensated claimants. Rows marked E show the characteristics of patients who were operated in high-volume hospitals (group 4) and lower-volume hospitals (groups 1–3).

a Primary osteoarthrosis (POA).

b Cementless THR based on NOMESCO classification of surgical codes.

c Statistically significant. Calculated using chi-square test. Any p-values < 0.05 were considered statistically significant.

Table 3. The relative risks (RRs) of claims, patient injuries, and specific technical error types in Groups 1–3 with Group 4 as reference group

	Hospital group (annual volume)^a
	All	Group 4 (≥ 400)	Group 3 (200–399)		Group 2 (100–199)		Group 1 (< 100)
	n = 21,571^b	n = 7,032^b	n = 3,525^b		n = 6,326^b		n = 4,688^b
	n	N	N	RR (95% CI)	N	RR (95% CI)	N	RR (95% CI)
Risks for filed claims:
All	563	120	98	1.6 (1.3–2.1)^d	205	1.9 (1.5–2.4)^d	140	1.8 (1.4–2.2)^d
Infection	121	28	18	1.3 (0.7–2.3)	47	1.9 (1.1–3.0)^d	28	1.5 (0.9–2.5)
Treatment injury	442	92	80	1.7 (1.3–2.3)^d	158	1.9 (1.5–2.5)^d	112	1.8 (1.4–2.4)^d
Risks for compensated claims:
All	250	44	40	1.8 (1.2–2.8)^d	106	2.7 (1.9–3.8)^d^e	60	2.1 (1.4–2.4)^d
Infection (intolerable injury)	53	12	6	1.0 (0.4–2.7)	23	2.1 (1.1–4.3)^d	12	1.5 (0.7–3.3)
Treatment injury (avoidable injury)	197	32	34	2.1 (1.3–3.4)^d	83	2.9 (1.9–4.3)^d	48	2.3 (1.4–3.5)^d
Risks for specific avoidable injuries:
Any technical error	189	30	31	2.1 (1.3-3.4)^d	83	3.1 (2.0-4.7)^d	45	2.3 (1.4-3.6)^d
Any cup-side error	80	6	14	4.7 (1.8–12)^d	40	7.4 (3.1–18)^d	20	5.0 (2.0–12)
Cup malposition	58	3	9	6.0 (1.6–22)^d	29	11 (3.3–35)^d	17	8.5 (2.5–29)^d
Any stem-side error	54	10	7	1.4 (0.5–3.7)^d	23	2.6 (1.2–5.4)^d	14	2.1 (0.9–4.7)^d
Stem malposition	33	6	3	1.0 (0.3–4.0)	15	2.8 (1.1–7.2)^d	9	2.3 (0.8–6.3)^d
Instable implant	44	7	9	2.6 (1.0–6.9)	19	3.0 (1.3–7.2)^d	9	1.9 (0.7–5.2)
Implant malposition	99	11	12	2.2 (1.0–4.9)	47	4.8 (2.5–9.2)^d^,f	29	4.0 (2.0–7.9)^d
Nerve and vascular injuries	43	13	7	1.1 (0.4–2.7)	16	1.4 (0.7–2.8)	7	0.8 (0.3–2.0)
Leg length discrepancy	19	6	3	1.0 (0.3–4.0)	8	1.5 (0.5–4.3)	2	0.5 (0.1–2.5)
Fracture treatment	22	2	4	4.0 (0.7–23)	8	4.5 (0.9–21)	8	6.0 (1.3–28)^d
Other surgical errors c	29	1	5	10 (1.2–85)^d	9	10 (1.3–79)^d	14	21 (2.8–160)^d
Multiple technical errors	34	1	5	10 (1.2–85)^d	12	12 (1.6–95)^d	16	22 (3.0–170)^d

Table shows the relative risks (RRs) and 95% confidence intervals (CIs) when group 4 hospitals were the reference group (RR = 1.00). No significant differences between group 1 and group 3 hospitals or between group 1 and group 2 hospitals were detected.

a Average annual primary THR volume of each hospital in the group.

b 3-year average volume of all hospitals in the group calculated between the years 2005 and 2010.

c Compensated errors associated with closure, cementing, drain pipe removal, failure to remove osteophytes, unfounded use of special implants, or use of non-compatible components.

d Statistically significant values compared to ≥ 400 hospitals.

^{e and f}show the statistically significant values compared to group 3 hospitals (RR of group 3 = 1.00).

^eRR = 1.5 (95% CI: 1.0–2.1). ^fRR = 2.2 (95% CI: 1.2–4.1).

Figure 1. Flow chart of data collection. NFB: any primary hip arthroplasty operation; NFC: any hip revision operation; NFJ: any hip fracture operation; NGB: any primary knee arthroplasty; NGC: any revision knee arthroplasty. ^a 2 claims of 10 were from high-volume hospitals (group 4). 9 claims were treatment injury claims, and 1 was an infection claim (group 3).

Figure 2. Types of patient injury. a Nerve or vascular lesions/injuries. b Percentage (%) of all perioperative technical errors. c Unplanned leg length difference of > 2 cm due to stem malposition. d Two patients had 3 errors.

Figure 3. Hospital volume and patient injuries. A. The association between high THR volume and lower incidence of claims filed, compensated claims, and perioperative technical errors. B. The number of compensated claimants with avoidable technical errors in each individual hospital performing total hip replacements (THRs) relative to hospital volume. Hospitals with over 50 primary THRs per year were included. The thick red line represents the average rate of compensated claimants with perioperative technical errors in Finnish hospitals. Hospitals below the line performed better than the national average.

Järvelin J, Häkkinen U, Rosenqvist G, Remes V. Factors predisposing to claims and compensations for patient injuries following total hip and knee arthroplasty. Acta Orthop 2012; 83(2): 190–6.

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