Excellent long-term survival of an uncemented press-fit stem and screw cup in young patients: Follow-up of 75 hips for 15–18 years

Figures & data

Table 1.  Diagnoses

	Hips
Primary osteoarthritis	26
Dysplasia, secondary osteoarthritis	21
Sequelae of CLP/slipped capital femoral epiphysis	7
Other secondary osteoarthritis	7
Rheumatoid arthritis	6
Avascular femoral head necrosis due to immunological/cytostatic treatment	5
Sequealae of femoral neck frature	3
Total	75

Table 2.  Breakdown of patient numbers according to Charnley categories. A: unilateral hip disorder; B: bilateral hip disorder; C: other conditions directly impeding mobility

Charnley category	At surgery	At follow-up
A	22	10
B	37	26
C	11	11
Total	70	47

Figure 1. The Zweymüller SL stem.

Figure 2. The Endler metal- (c.p. titanium-) backed screw cup.

Figure 3. Frontal radiograph with Gruen femoral zones 1–7 and De Lee-Charnley acetabular zones I—III. Polyethylene wear was estimated along a line from the superior to the inferior edge margins of the cup. The distances from the superior (A) and the inferior (B) edge margins to the femoral head were measured with a manual calliper. Linear wear was calculated using the formula (A-B) /2.The measurements were corrected for magnification using the 32-mm diameter of the femoral head.

short-legendFigure 4.

Table 3.  Characteristics of the reoperated hips

A	B	C	D	E	F	G	H	I^a	J	K^a	L^a	M^a
1^b	F	56	20	Primary OA	2	4	Loosening	F+A	No	No	F+A	No
2^b	F	58	20	Primary OA	2	10	Loosening	F	Yes	Prox. F	F+A	Yes–F
3	F	52	27	Dysplasia	1	9	Wear	No	Yes^c	No	A	No
4	F	49	34	Dysplasia	1	10	Pain, wear	No	Yes	Prox. F	A	Yes–F
5	F	50	31	Primary OA	1	10	Pain, wear	No	Yes	Prox. F	A	Yes–F
6	M	58	29	Sepuele femoral neck fracture	1	11	Neck fracture of the stem	No	No	No	F	No
7	M	43	25	Primary OA	2	12	Pain, wear	No	Yes	Prox. F	A	Yes–F+A
8	M	51	22	Primary OA	1	13	Wear	No	Yes^c	A	A	Yes–A

^a F-femur; A–acetabulum

^b hips 1 and 2 represent the bilaterally reoperated patient.

A Hip

B Sex: F–female, M–male

C Age at surgery

D BMI at surgery

E Indication

F Charnley category

G Time to revision

H Cause of reoperation

I Loosening

J Wear (^c excessive)

K Osteolysis

L Exchange of component

M Bone grafting

Figure 5. Kaplan-Meier estimated survival curves, both components, all revisions.

Figure 6. Kaplan-Meier estimated cup survival curves, all revisions.

Figure 7. Kaplan-Meier estimated stem survival curves, all revisions.