Small Head metal-on-metal Total Hip Arthroplasty shows Satis
The Metasul articular interface was introduced as a promising second-generation MoM THA with advanced production technology, better clearances, and increased metal hardness. The failure of cup osseointegration caused the manufacturer to recall these implants.

168 consecutive primary Metasul THAs were performed in 144 patients. Most patients received a cementless femoral and porous-coated acetabular component with 28 mm head. A competing risk analysis was done for determination separately for bearing surface-related, recalled bearing failure and end point revision for any reason. For clinical patient evaluation HHS and UCLA scores were used. Cobalt and Chromium ions levels measurement and standard radiographic assessment was done.

--Of the 168 THAs, 19 hips were revised at a mean period of 15 years as follows: 12 of them were due to recalled acetabular component, 5 hips had non interface related complication and 2 true interface surface failure.

--The survival distribution function of all hips with revision for any reason was 88.4%, for bearing interface-relation 98.8%, and 92.6% for recalled cups.

--The mean Harris Hip Score and UCLA scores were 85 and 6 respectively and the median Co and Cr blood level were 1.0 and 0.91 microg/L.

In conclusion, except the recalled elements, the Metasul articular interface has performed exceptionally well in this relatively young population over a minimum of 15 years of follow-up. In the entire cohort, there were two interface-related updates.