Revisions of Monoblock Metal-on-metal THAs Have High Early Complication Rates

Background Isolated revision of the acetabular component in the setting of total hip arthroplasty has an increased risk of dislocation. With local soft tissue destruction frequently associated with failed metal-on-metal (MoM) bearings, it is presumed that acetabular revision of these hips will have even greater risk of complications. However, no study directly compares the complications of MoM with metal-on-polyethylene (MoP) acetabular revisions. Questions/purposes In the context of a large database analysis, we asked the following questions: (1) Are there differences in early medical or wound complications after isolated acetabular revision of MoM and MoP bearing surfaces? (2) Are there differences in the frequency of dislocation, deep infection, and rerevision based on the bearing surface of the original implant? Methods A review of the 100% Medicare database from 2005 to 2012 was performed using International Classification of Diseases, 9th Revision and Current Procedural Terminology codes. We identified 451 patients with a MoM bearing and 628 patients with a MoP bearing who had an isolated acetabular revision and a minimum followup of 2 years. The incidence, odds ratios, and 95% confidence intervals for early medical or wound complications were calculated using a univariate analysis at 30 days with patient sex and age group-adjusted analysis for blood transfusion. The incidence, odds ratio, and 95% confidence intervals for dislocation, deep infection, and rerevision were calculated using a univariate analysis at 30 day, 90 days, 1 year, and 2 years using a subgroup analysis with the Cochran-Mantel-Haenszel test to adjust for patient gender and age groups. Results There were no differences between the MoM and MoP isolated acetabular revisions in the incidence of 30-day local complications.

Section: Discussioncontrasting

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Complications Are Not Increased With Acetabular Revision of Metal-on-metal Total Hip Arthroplasty

Penrose

Seyler

Wellman

et al. 2016

“…As there are no other published studies reporting on difficulties of head removal except FDA case reports, we cannot compare our results with those of other studies. In general, revisions of MoM implants have a high risk for complications [15,20]. In the current study, we compared revisions of MoM implants (M 2 a-Magnum TM groups) in which the head could be removed with or without problems.…”

Section: Discussionmentioning

confidence: 99%

Modular to Monoblock: Difficulties of Detaching the M2a-MagnumTM Head Are Common in Metal-on-metal Revisions

Mäntymäki

Mäkelä

Vahlberg

et al. 2016

Background Modern hip implants typically feature modular heads, which allow for easy exchange and removal from the femoral stem at the time of revision. However, owing to fretting, corrosion, or cold welding, the modular head may be difficult or impossible to separate from the underlying trunnion, especially if the implant has titanium interfaces between the head and the stem. We have repeatedly encountered difficulty removing the titanium sleeve adapter in the M 2 a-Magnum TM implant. Although the manufacturer warns about this complication and cases with these difficulties have been reported to the United States FDA, we believed this topic is important to study, because the frequency of difficulties in head removal is unknown and the complications related to this event have not been characterized. Although the global use of metal-on-metal implants in THAs has decreased dramatically during the last several years, many thousands remain in service and therefore still might require revision. It is crucial to be prepared with special tools, including a femoral head extraction tool and diamond saw. The patient has to be informed of the possibility of a more extensive operation than preoperatively planned. Level of Evidence Level III, therapeutic study.123 Clin Orthop Relat Res (2016) 474:1999-2005 DOI 10.1007/s11999-016-4774-7 Clinical Orthopaedics and Related Research ® A Publication of The Association of Bone and Joint Surgeons® stem revision owing to difficulties with head removal.

“…Risk factors for component revision were younger age at surgery, higher cup angle of inclination, and female sex. Revisions for ARMD can be complex with extensive bone loss and damage to the surrounding soft tissue encountered intraoperatively and prone to complications and rerevisions [38,47,51].…”

Section: Introductionmentioning

confidence: 99%

Adverse Reactions to Metal on Metal Are Not Exclusive to Large Heads in Total Hip Arthroplasty

Lombardi

Berend

Adams

et al. 2016

Background There is some suggestion that smaller diameter heads in metal-on-metal total hip arthroplasty (MoM THA) may be less prone to the adverse reactions to metal debris (ARMD) seen with large-diameter heads. Questions/purposes We reviewed our population of patients with small head (B 32 mm) MoM THA to determine (1) the frequency of ARMD; (2) potential risk factors for ARMD in this population; and (3) the etiology of revision and Kaplan-Meier survivorship with revision for all causes. Methods Small-diameter head MoM devices were used in 9% (347 of 3753) of primary THAs during the study period (January 1996 to March 2005. We generally used these implants in younger, more active, higher-demand patients. Three hundred hips (258 patients) had MoM THA using a titanium modular acetabular component with a cobaltchromium tapered insert and were available for review with minimum 2-year followup (mean, 10 years; range, 2-19 years). Complete followup was available in 86% of hips (300 of 347). Clinical records and radiographs were reviewed to determine the frequency and etiology of revision. Kaplan-Meier survivorship analysis was performed. Results ARMD frequency was 5% (14 of 300 hips) and represented 70% (14 of 20) of revisions performed. Using multivariate analysis, no variable tested, including height, weight, body mass index, age, cup diameter, cup angle, use of screws, stem diameter, stem type, head diameter, preoperative clinical score, diagnosis, activity level, or sex, was significant as a risk factor for revision. Twenty hips have been revised: two for infection, four for aseptic loosening, and 14 for ARMD. Kaplan-Meier analysis The institution of one or more of the authors (AVL, KRB, JBA, KLS) has received funding from Biomet, Inc (Warsaw, IN, USA), Pacira Pharmaceuticals Inc (Parsippany, NJ, USA), and Orthosensor (Dania Beach, FL, USA). One of the authors certifies that he (AVL) has or may receive payments or benefits, during the study period, an amount of more than USD 1,000,001 from Biomet, Inc, an amount of USD 10,000 to USD 100,000 from Innomed, Inc (Savannah, GA, USA), an amount of less than USD 10,000 from Pacira Pharmaceuticals Inc, and an amount of less than USD 10,000 from Orthosensor. One of the authors certifies that he (KRB) has or may receive payments or benefits, during the study period, an amount of more than USD 1,000,001 from Biomet, Inc. revealed survival free of component revision for all causes was 95% at 10 years (95% confidence interval [CI], 91%-97%), 92% at 15 years (95% CI, 87%-95%), and 72% at 19 years (95% CI, 43%-90%), and survival free of component revision for aseptic causes was 96% at 10 years (95% CI, 92%-98%), 92% at 15 years (95% CI, 88%-95%), and 73% at 19 years (95%