Failure mechanisms in uncemented Kudo type 5 elbow prosthesis in patients with rheumatoid arthritis: 7 of 49 ulnar components revised because of loosening after 2–10 years

Figures & data

Figure 1. The Kudo elbow prosthesis. Upper panel shows both components with a porous coat. Lower panel shows both components without a porous coat. The all-polyethyl-ene ulna component is not pictured.

Figure 2. Schematics used to determine the malalignment of the components. A–D: ideal alignment of the components; the axis of the component is parallel to the defined axis of the humerus and ulna, respectively. Deviation from the axis in valgus-varus and flexion-extension was measured in degrees (arrow).

Figure 3. Postoperative lateral and AP radiograph (case 25; Table). The humeral component is positioned in varus; the ulnar component is positioned in varus and flexion. The malalignment relative to the axis of the bone is illustrated. Also, note the subluxation with valgus tilt of the prosthesis.

Details of all 49 patients in the series

A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q	R
1	41	–	2	90	1	1	–	–	–	–	–	0	E	0	–	90	11.0
2	30	–	2	100	1	1	1	–	–	–	–	0	G	2	–	90	10.6
3	32	–	0	95	1	–	–	–	–	–	–	0	G	0	–	100	10.2
4	76	–	2	50	1	–	–	–	–	–	–	0	G	0	–	110	10.2
5	48	–	2	70	1	1	–	–	–	–	+	0	E	2	–	105	9.5
6	54	–	2	60	1	–	–	–	–	–	–	0	G	1	–	100	9.4
7	56	–	2	70	1	–	–	–	–	–	–	0	E	0	–	95	9.4
8	53	–	2	110	1	1	–	–	–	–/+	–	1	E	0	–	105	9.1
9	43	–	2	60	1	–	–	+	7.6	+/–	–	2	(E)	(0)	–	(100)	(8.6)
10	53	–	2	100	1	–	–	–	–	–/+	–	0	E	1	–	115	8.7
11	56	–	2	95	1	–	–	–	–	+/–	–	0	E	0	–	90	8.8
12	51	–	1	30	1	–	–	–	–	–	–	0	E	0	–	90	8.5
13	55	–	2	40	1	3	2	–	–	–	–	1	E	0	–	90	8.5
14	33	–	0	110	1	–	–	–	–	–	–	0	G	0	+	110	8.4
15	31	–	2	110	1	1	1	–	–	–	–	0	E	1	–	100	8.3
16	28	–	2	80	1	–	–	+	4.5	+/–	+	0	(G)	(0)	–	(80)	(6.0)
17	53	–	3	40	1	1,6	1,4	–	–	–	–	0	F	0	–	100	8.1
18	78	–	0	95	1	1,2,4	–	–	–	–	–	0	E	0	–	110	7.9
19	74	–	2	90	1	–	–	–	–	–	–	0	F	0	–	110	7.7
20	79	–	0	60	1	–	–	–	–	–	–	1	E	0	–	100	7.4
21	68	+	1	115	2	1,5	3	–	–	+/–	–	0	E	2	–	120	7.1
22	75	–	3	50	2	1	–	–	–	+/–	+	0	F	1	–	100	7.1
23	32	–	2	110	1	–	–	–	–	–	–	0	E	0	–	132	6.9
24	23	–	3	65	1	6	4	–	–	–	–	0	E	0	–	100	7.1
25	73	–	3	125	2	–	–	+	4.6	+/–	+	2	(P)	(2)	–	(90)	(6.8)
26	24	–	3	115	2	6	4,5	–	–	–	–	0	E	0	–	105	6.8
27	69	–	3	90	2	–	–	–	–	–	–	2	E	0	–	130	6.6
28	56	–	3	70	2	1	–	–	–	–	–	0	E	0	–	100	6.4
29	73	–	3	90	2	–	–	–	–	–	–	0	F	0	–	110	6.4
30	56	–	0	110	2	–	–	–	–	–	–	0	E	0	–	75	6.2
31	55	–	0	70	1	–	–	+	6.3	+/–	+	0	(E)	(0)	–	(90)	(6.2)
32	62	–	0	95	2	–	–	–	–	–	–	0	F	0	–	60	6.1
33	69	+	0	110	2	–	–	–	–	–	–	2	E	2	–	100	6.0
34	50	–	0	120	1	1	1	–	–	–	+	0	E	2	–	100	6.0
35	66	–	0	105	2	–	–	–	–	–	–	0	E	1	–	110	6.0
36	56	–	0	90	2	–	–	–	–	+/–		1	G	0	–	90	6.0
37	60	–	0	120	2	–	–	+	4.0	+/–	+	2	(E)	(0)	+	(110)	(6.0)
38	55	–	0	70	1	–	–	–	–	–	–	0	E	0	–	105	5.7
39	57	–	0	115	2	–	–	–	–	–	–	0	E	0	–	85	5.7
40	35	–	0	70	2	–	–	–	–	–	–	0	E	0	+	90	5.2
41	65	–	0	100	2	–	–	–	–	–	–	0	E	0	–	95	5.0
42	83	+	0	60	2	–	–	–	–	–	–	0	E	0	–	120	5.0
43	36	–	0	45	2	–	–	–	–	–	–	0	G	0	–	75	4.7
44	52	+	0	85	2	–	–	–	–	–	–	0	E	2	–	130	(4.0)
45	66	–	0	100	2	–	–	–	–	–	–	2	E	0	–	95	4.0
46	84	–	0	85	2	–	–	–	–	–	–	0	E	0	–	80	4.0
47	72	–	0	110	1	–	–	+	1.6	+/–	–	2	(E)	(0)	(+)	(85)	(4.0)
48	76	–	0	100	1	–	–	+	1.5	+/–	–	1	(P)	(0)	–	(105)	(3.4)
49	69	–	2	140	2	–	–	–	–	+/–	+	0	P	0	–	125	2.0

Figure 4. Lateral and AP radiographs of the same prosthesis as in Figure 3, 2 years after insertion. There is marked osteolysis around the ulnar stem (white arrows).

Figure 5. Lateral and AP radiographs of the same prosthesis at the time of revision (4.6 years after implantation); osteolysis around the ulnar stem has caused fracture of the ulna (white arrows).

Legends to Table

A Case no.	2 intravenous antibiotics
B Age at surgery	3 cerclage wiring
C Ulnar neuropatphy preoperatively	4 arthrolysis
D Stability	5 loose fragment removed
0 stable	I Revision
1 < 3 mm joint opening	J Time to revision, years
2 3–6 mm joint opening	K Radiolucency ulnar/humeral component
3 < 6 mm joint opening	L Valgus tilt and subluxation of the prosthesis
E Range of motion preoperatively	M Alignment of ulna
F Size of ulnar stem	0 0°–5°
1 short	1 5°–10°
2 long	2 < 10°
G Complications peri- and postoperatively,	N EFA elbow function assessment scale score
excluding revisions	E excellent
1 ulnar neuropathy	G good
2 radial nerve neuropathy	F fair
3 superficial wound infection	P poor
4 medial epicondyle fracture	O Stability of prosthesis (as in D)
5 ulnar fracture	P Ulnar neuropathy
6 reduced range of motion	Q ROM at follow-up
H Treatment	R Follow-up, years
1 decompression