Does a titanium sleeve reduce the frequency of pseudotumors in metal-on-metal total hip arthroplasty at 5-7years follow-up?
Little is known about pseudotumor frequency and risk factors for pseudotumor formation among different types of metal-on-metal (MoM) hip arthroplasties. A lower release of chromium and cobalt have been reported in MoM hip arthroplasties with a titanium sleeve compared to MoM designs without a titanium sleeve, but yet it is unknown whether a titanium sleeve reduces the pseudotumor frequency. We conducted a cross-sectional study to investigate: 1) pseudotumor frequency, 2) risk factors of pseudotumor formation 3) and correlations between pseudotumors, serum metal-ions, implant position, and clinical symptoms.



We expected a lower pseudotumor frequency in MoM hip articulation with a titanium sleeve than reported in MoM hip articulation designs using chromium-cobalt sleeve.



A consecutive series of 41 patients/49 hips (31 males), mean age 52 (28-68) years, participated in a 5.5±0.5 (4-6.5) year follow-up study of their M2a_Magnum hip articulation (Biomet Inc., Warsaw, Indiana, USA). Patients were evaluated with magnetic resonance imaging (MRI), measurements of serum metal-ions, plain radiographs, and clinical outcome measures of Harris Hip Score (HHS) and Oxford Hip Score (OHS).



Eighteen of 47 hips (38%) had MRI-verified pseudotumors, all cystic, with a mean dimension of 10.6×25.6×41mm. Digital measurements on plain radiographs revealed a higher cup anteversion in patients with a pseudotumor of mean 28.4°±5.05° compared to mean 23.5°±6.5° in patients without a pseudotumor (P=0.009). Serum metal-ion concentrations, acetabular cup inclination and measures of HHS and OHS were similar between patients with and without a pseudotumor (P>0.46).



At 5.5±0.5years after surgery, MRI-verified cystic pseudotumors were frequently observed in M2a_Magnum hip articulations despite the use of titanium sleeves. The pseudotumors were related to high cup anteversion angles but not related to high serum metal-ions or clinical symptoms.



IV: cross-sectional study.
Department of Orthopaedics, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark. Electronic address: mettehh20@gmail.dk.
M H
MH
Hjorth
Department of Radiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark.
N
N
Egund
Department of Orthopaedics, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark; Centre of Research in Rehabilitation (CORIR), Department of Clinical Medicine, Aarhus University, Denmark.
I
I
Mechlenburg
Department of Radiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark.
J
J
Gelineck
Department of Orthopaedics, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
S S
SS
Jakobsen
Department of Orthopaedics, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark; Orthopaedic Research Unit, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
K
K
Soballe
Orthopaedic Research Unit, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark; Department of Clinical Medicine, Aarhus University, Denmark.
M
M
Stilling
D000077:Acetabulum; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D002857:Chromium / Q000097:blood; D003035:Cobalt / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006104:Granuloma, Plasma Cell / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008875:Middle Aged; D011474:Prosthesis Design; D011859:Radiography; D012307:Risk Factors; D014025:Titanium
D002857:Chromium; D003035:Cobalt; D014025:Titanium
Clinical outcome measures; Magnetic resonance imaging; Metal-on-metal total hip arthroplasty; Pseudotumor; Serum metal-ion levels; Titanium sleeve