N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases

Table 1

Chelation therapy in metal hip-implanted patients: in table patient’s medical history, clinical manifestations, chelating agents, and metals blood levels before and after chelation treatment concerning the presented cases and those published in literature are reported.

Age/sex	Comorbidity	Hip type	Latency from implant to symptoms or blood metals	⁢Clinical manifestations		Implant revision	Co/Cr blood levels acme before chelation	Chelating therapy (cycles)	Co/Cr blood levels after chelation	Reference
				Local	Systemic
58/F	Type 2 D; Hypert.	MOP	6–9 months	Prosthesis wear and local metallosis	Visual/hearing loss; II–VII cranial nerve disorders; Sensorimotor disorders; Mild hypothyroidism	Yes	Co 549 mcg/L; Cr 54 mcg/L	EDTA i.v.; (25 one-day cycles)	Reduced (not specified)	[7]
56/M	Type 2 D	MOM	14–20 months	Prosthesis wear and hip dislocation	Hearing loss; Sensorimotor disorders; Walking difficulties; Pericardial effusion; Cardiomegaly; Subclinical hypothyroidism	Yes	Co 506 mcg/L; Cr 14.3 mcg/L	DMPS oral (14 mg/kg/day for 6 days, 4 mg/kg for 5 days, and; 4 mg/kg for 4 days)	Reduced (not specified)	[8]
52/M	—	MOP	Not specified	Periarticular painful fluctuant mass with black fluid at aspiration	Dilated cardiomyopathy; Pericardial effusion; Liver failure; Hypothyroidism; EXITUS due to severe MOF	No	Co 1085 mcg/L; Cr not reported	Dimercaprol; (1 three-day cycle)	Co decrease (by 33%)	[9]
55/M	—	MOP	24 months	Myositis ossificans like picture	Visual/hearing loss; Cardiomyopathy; Hypothyroidism	Yes	Co 885 mcg/L; Cr 48.8 mcg/L	DMPS; (Not specified)	Not specified	[10]
75/M	—	MOM	60 months	Prosthesis wear and local metallosis	Asthenia; Dilated cardiomyopathy; Pericardial effusion	Yes	Co 46.5 mcg/L; Cr 76.1 mcg/L	NAC oral + i.v.; (i.v.: 150 mg/kg bolus + 300 mg/kg/d for 10 days); (Oral: 2 seven-day cycles at 100 mg/kg/d for each cycle)	Co/Cr decrease (by 51% and 40%)	[11]
67/M	Cochlear implant Hypert.	MOM	30 months	Little fluid collection near the acetabular cup	No	No	Co 22.5 mcg/L; Cr 7.4 mcg/L	NAC oral; (Oral 300 mg/kg/day for 10 days)	Co/Cr decrease (by 86% and 87%)	Case  1
81/F	COPD, SLE; Mitral/Aort. reg.; Renal imp.; Euthyr. goiter; Hypert., cataracts	MOM	65 months	Fluid collection near hip prosthesis	No	No	Co 21.1 mcg/L; Cr 11.8	NAC oral; (Oral 300 mg/kg/day for 9 days)	Co/Cr decrease (by 45% and 24%)	Case  2

M/F: male/female; Type 2 D: type 2 diabetes; Hypert.: hypertension; COPD: chronic obstructive pulmonary disease; SLE: systemic lupus erythematosus; Mitral/Aort. reg.: moderate mitral and aortic valve regurgitation; Renal imp.: mild renal impairment; Euthyr. goiter: Euthyroid multinodular goiter; Co: cobalt; Cr: chromium; MOP: metal on polyethylene; MOM: metal-on-metal; EDTA: edetate calcium disodium; DMPS: sodium 2,3-dimercaptopropane sulfonate; NAC: N-acetyl-cysteine; the prosthesis has been implanted after the rupture of a previous ceramic hip implant.