Total hip arthroplasty in young adults, with focus on Perthes' disease and slipped capital femoral epiphysis

Figures & data

Flow of patients and THAs through the study.

Table 1. Baseline characteristics of attendees and non-attendees for the cohort and for subjects with THA secondary to Perthes'/SCFE reported to the NAR

	Attendees	95% CI	Non-attendees	95% CI	p-value
Number of patients	500		232
Male, n (%)	218 (44%)	39–48	127 (55%)	48–61	0.008
Age at THA, mean	28.7	28–29	28.3	27–29	0.5
Type of underlying diagnosis, n (%)
Primary osteoarthrosis	28 (5.6%)	3.5–7.7	19 (8.3%)	4.6–12	0.2
JIA / RA	81 (16.1%)	13–20	25 (11%)	6.7–15	0.06
Sequelae of femoral neck fracture	26 (5.2%)	3.2–7.2	19 (8.3%)	4.6–12	0.1
Sequelae of DDH	129 (25.7%)	22–30	44(19%)	14–24	0.052
Sequelae of Perthes'/ SCFE	91 (18.1%)	15–22	42 (18%)	13–23	1.0
Ankylosing spondylitis	20 (4.0%)	2.2–5.8	8 (3.5%)	1.1–5.8	0.7
Acute femoral neck fracture	2 (0.4%)	–1.6 to 2.4	0		0.3
Others	126 (25.1%)	21–29	73 (32%)	25–38	0.06
Perthes' disease/SCFE	91		42
Male, n (%)	61 (67%)	57–77	32 (76%)	9.3–18	0.3
Age at THA, mean	27.5	26–29	25.8	24–28	0.2

JIA: juvenile idiopathic arthritis; RA: rheumatoid arthritis; DDH: developmental dysplasia of the hip;

SCFE: slipped capital femoral epiphysis.

Table 2. Validation of diagnoses reported to the Norwegian Arthroplasty Register based on the original medical records and patient self-reporting

Diagnosis as reported to the NAR	No. of THAs	Correct diagnosis	95% CI
Primary osteoarthrosis	31	19 (61%)	44–79
JIA / RA	112	109 (97%)	94–100
Sequelae of femoral neck fracture	26	25 (96%)	87–104
Sequelae of DDH	150	132 (88%)	83–93
Sequelae of Perthes'/SCFE	94	89 (95%)	90–99
Ankylosing spondylitis (morbus Bechterew)	28	28 (100%)	100–100
Acute fracture of the femoral neck	2	2 (100%)	100–100
Others, specified	145	134 (92%)	84–101
Missing diagnosis	4	0	0–0
Total	592	538

Abbreviations: See Table 1.

Table 3. Frequency of different hip disorders after validation. In 5 hips, 2 diagnosis were likely: 2 hips showed RA and DDH (same patient) and 3 hips showed DDH and Perthes' disease

Diagnosis	Correct numbers after validation (hips)
Primary arthrosis	18
JIA / RA	110
Sequelae of femoral neck fracture	31
Sequelae of DDH	142
Sequelae of Perthes' disease	72
Sequelae of SCFE	29
Ankylosing spondylitis	30
Acute fracture of the femoral neck	2
Others, specified	162
Missing diagnosis	0

Abbreviations: See Table 1.

Table 4. EQ-5D index for patients with different diagnoses

Diagnosis	EQ-5D scores ^a	(95% CI)
Primary osteoarthrosis	73	61–85
JIA / RA	66	61–71
Sequelae of femoral neck fracture	68	59–77
Sequelae of DDH	69	65–73
Sequelae of Perthes	74	70–79
Sequelae of SCFE	81	75–87
Ankylosing spondylithis	73	64–82
Acute fracture of the femoral neck ^b	44	36–52
Others, specified	74	70–78
All diagnoses	71	69–73

^a 0 = worse imaginable health; 100 = best possible health.

^b Only 2 patients were operated due to acute fracture of the femoral neck.