Research Article: Revision of metal-on-metal hip arthroplasty in a tertiary center

Date Published: June 31, 2013

Publisher: Informa Healthcare

Author(s): Alexander D Liddle, Keshtra Satchithananda, Johann Henckel, Shiraz A Sabah, Karuniyan V Vipulendran, Angus Lewis, John A Skinner, Adam W M Mitchell, Alister J Hart.

http://doi.org/10.3109/17453674.2013.797313

Abstract

Operative findings during revision of metal-on-metal hip arthroplasty (MOMHA) vary widely and can involve massive soft tissue and bone disruption. As a result, planning of theater time and resources is difficult, surgery is challenging, and outcomes are often poor. We describe our experience with revision of MOMHA and provide recommendations for management.

We present the findings and outcomes of 39 consecutive MOMHAs (in 35 patients) revised in a tertiary unit (median follow-up time 30 (12–54) months). The patients underwent a preoperative work-up including CT, metal artifact reduction sequence (MARS) MRI, and blood metal ion levels.

We determined 5 categories of failure. 8 of 39 hips had conventional failure mechanisms including infection and impingement. Of the other 31 hips, 14 showed synovitis without significant disruption of soft tissue; 6 had a cystic pseudotumor with significant soft tissue disruption; 7 had significant osteolysis; and 4 had a solid pseudotumor. Each category of failure had specific surgical hazards that could be addressed preoperatively. There were 2 reoperations and 1 patient (2 hips) died of an unrelated cause. Median Oxford hip score (OHS) was 37 (9–48); median change (ΔOHS) was 17 (–10 to 41) points. ΔOHS was similar in all groups—except those patients with solid pseudotumors and those revised to metal-on-metal bearings, who fared worse.

Planning in revision MOMHA is aided by knowledge of the different categories of failure to enable choice of appropriate personnel, theater time, and equipment. With this knowledge, satisfactory outcomes can be achieved in revision of metal-on-metal hip arthroplasty.

Partial Text

We present preoperative and outcome data on all patients who were revised for a painful MOMHA at our institution between 2007 and 2010. 39 hips in 35 patients (32 females) were revised during the study period. The median age was 61 (25–74) years. For all patients, data in the following categories were collected prospectively: preoperative and postoperative functional scoring, radiological findings, blood analysis (trace metal analysis, renal function tests, inflammatory markers), histology, and microbiology.

Most of the patients were tertiary referrals and this is reflected in the heterogeneity of implant designs revised (Table 1). Most cases were resurfacing prostheses (32/39), and most of these (21/32) were Birmingham Hip Resurfacings (Smith and Nephew Inc., Memphis, TN). Median survivorship after implantation of the primary prosthesis was 47 (11–131) months. Median preoperative OHS was 15 (2–31). Median follow-up time was 30 (12–54) months.

This paper outlines our experience of revision of MOMHA, gained over a 4-year period in a tertiary referral unit, with a median follow-up time of 30 months. Due to the nature of the unit’s practice, the study population shows great heterogeneity of demographics, implant type, and manufacturer, and as a result we have encountered a wide variety of failure mechanisms. This has provided a challenge, which has been addressed using a multidisciplinary approach to preoperative planning, revision surgery, and postoperative follow-up. As the revision burden of this type of implant increases, these challenges are being encountered by more surgeons and more units. It is our intention that the lessons we have learned will be of help to units with less experience.

 

Source:

http://doi.org/10.3109/17453674.2013.797313