Adverse reaction to metal debris after ReCap-M2A-Magnum large-diameter-head metal-on-metal total hip arthroplasty

Figures & data

Table 1. Patient characteristics and results (74 patients, 80 hips). Data on swelling, clicking, sensation of subluxation, mean OHS (range), and OHS classification are given hipwise for 77 hips (data for 3 hips are missing). The data for mean inclination angle of the cup (range) are given hipwise for 80 hips

	Total	ARMD	ARMD probable or possible	ARMD not found
Patients, n	74	11	29	34
Males, n	24	4	13	7
Mean age, years (range)	67 (42–82)	66 (58–75)	70 (53–82)	65 (42–81)
Mean follow-up, years (range)	6.0 (5.5–6.7)	6.0 (5.6–6.3)	5.9 (5.5–6.3)	6.0 (5.6–6.7)
Mean serum cobalt, µg/L (range)	3.7 (0.4–42.5)	12.8 (2.9–42.5)	2.2 (0.8–7.7)	2.1 (0.4–4.4)
Mean serum chromium, µg/L (range)	3.6 (0.5–49.1)	12.4 (2.5–49.1)	2.1 (0.5–7.2)	2.0 (0.6–4.2)
Hips, n	80	11	32	37
Swelling, n	9	4	3	2
Clicking, n	16	6	5	5
Subluxation sensation, n	14	5	4	5
Mean inclination angle of the cup, degrees (range)	45 (23–62)	46 (37–62)	46 (28–57)	44 (23–55)
Mean OHSa (range)	41 (13–48)	36 (13–48)	41 (15–48)	42 (23–48)
OHS excellent, n	52	4	23	25
OHS good, n	10	1	4	5
OHS fair, n	9	5	2	2
OHS poor, n	6	1	2	3

ARMD: adverse reaction to metal debris.

OHS: Oxford hip score: 42–48, excellent; 34–41, good; 27–33, fair; 0–26, poor.

Table 2. Data on the 3 patients who required revision because of an adverse reaction to metal debris (ARMD)

A	B	C	D	E	F	G	H	I	J	K	L	M	N
58 F	33	M	No	Yes	Yes	2.5	3.8	41	Solid mass and fluid 60 × 30 × 30 mm	Pseudotumor	Cold-welded	ETO + revision of stem and cup	Neg
71 M	29	M	Yes	No	Yes	4.9	6.6	57	Fluid 29 × 76 × 62 mm	Milk-like yellowish fluid	Cold-welded	Revision of the stem + Avantage	Neg
65 F	32	M	Yes	Yes	No	13.5	24.0	45	Fluid 90 × 130 × 70 mm	Milk-like yellowish fluid, pseudotumor, gluteus medius muscle necrosis	Corrosion of trunnion and adapter	Avantage	Neg

A Age and gender

B OHS, See Table 1

C Pain

 M = Moderate

D Clicking

E Subluxation sensation

F Swelling

G Serum chromium level µg/L

H serum cobalt level µg/L

I Cup inclination angle in degrees

J Magnetic resonance imaging

K Status of the hip at revision (all had ARMD)

L Status of the trunnion/head at revision

 Cold-welded = the Magnum head could not be detached from the adapter and trunnion

M The procedure performed in revision

 ETO = extended trochanter osteotomy to revise the stem

 Avantage = the Biomet Dual-Mobility E1 mobile polyethylene liner.

N Bacterial culture

Table 3. Data on 8 patients who were considered to have ARMD but who had not undergone revision surgery. See Table 2 for explanation of abbreviations

A	B	C	D	E	F	G	H	I	J	K
70 M	47	No	No	No	No	49.1	11.3	41	Fluid 60 × 70 × 20 mm	Revision scheduled
60 F	37	Mild	No	Yes	No	7.8	10.0	53	Fluid 25 × 35 × 40 mm	Strict follow-up
61 M	32	Moderate	Yes	No	No	26.1	42.5	62	Fluid 60 × 70 × 22 mm	Revision scheduled
66 F	48	No	Yes	No	No	2.9	2.9	37	Solid and fluid 76 × 30 × 1 mm and 30 × 20 × 20 mm	Strict follow-up
66 F	45	Mild	Yes	Yes	No	10.2	6.7	50	No findings	Strict follow-up
63 M	47	Mild	No	No	Yes	9.1	8.4	40	Solid 60 × 60 × 90 mm	Revision scheduled
75 F	27	Moderate	Yes	Yes	No	5.4	14.1	39	Fluid 47 × 13 × 70 mm	Patient did not want revision
71 F	13	Hard	No	No	Yes	4.8	10.0	42	No findings	Strict follow-up

A–J: See Table 2

K Status of the patient

Table 4. Associations between certain risk factors for ARMD in patients with ARMD and patients without ARMD. Odds ratios (ORs) and 95% confidence intervals (CIs) by univariable multinomial logistic regression analysis. A sensation of subluxation, clicking, and a poor OHS score were related to ARMD. One unit increase in OHS score was considered statistically significant in the definite ARMD group

	ARMD vs. ARMD not found		ARMD probable or possible vs. ARMD not found
	OR (95% CI)	p-value	OR (95% CI)	p-value
Age	1.0 (0.95–1.1)	0.5	1.1 (1.0–1.2)	0.02
Gender (female vs. male)	0.6 (0.1–2.4)	0.4	0.4 (0.1–1.0)	0.05
Side	4.4 (1.0–19)	0.05	0.8 (0.3–2.0)	0.6
Subluxation sensation	5.0 (1.1–23)	0.04	0.9 (0.2–3.7)	0.9
Clicking	7.2 (1.6–33)	0.01	1.2 (0.3–4.4)	0.8
Swelling	9.4 (1.4–62)	0.02	1.8 (0.3–11)	0.5
Inclination angle of the cup	1.0 (0.95–1.1)	0.4	1.0 (0.97–1.1)	0.2
OHS score	1.1 (1.0–1.2)	0.03	1.0 (0.95–1.1)	0.7
OHS poor and fair vs. good and excellent	7.2 (1.6–33)	0.01	0.9 (0.2–3.7)	0.9
Bilateral ReCap-M2a-Magnum	0.4 (0.05–3.9)	0.5	0.6 (0.2–2.3)	0.5
Bilateral MoM THA	0.6 (0.1–2.4)	0.4	0.6 (0.2–1.6)	0.3
Bilateral THA	0.4 (0.1–1.8)	0.2	0.7 (0.3–1.7)	0.4