|Beitragstitel||Prosthetic loosening due to metallosis caused by disintegration of the Sulmesh layer of a Fitmore cup|
After total hip arthroplasty metallosis (adverse reaction to metal debris ARMD, aseptic lymphocytic vasculitis associated lesion ALVAL) is mainly associated to metal-on-metal bearing surfaces utilizing large heads (≥ 36mm) and trunnionosis, defined as metal wear at the head-neck junction of a total hip implant.
We report a case where disintegration of the osteo-integrated parts of the Sulmesh layer of a Fitmore cup created metallosis and loosening of a total hip arthroplasty.
An 81 year-old woman presented in our outpatient department with mechanical pain in the groin when walking or sitting 15 years after left total hip arthroplasty. The arthroplasty consisted of a Fitmore cup with a Metasul 28 mm inlay and a non-cemented Spotorno stem. Clinical examination showed a reduced and painful passive mobility of the left hip. Standard radiographs revealed loosening of the prosthetic cup and stem. Loosening was confirmed with a CT-scan, but additionally parts of the Sulmesh layer were detached from the acetabular cup. No signs of prosthetic joint infection were present with laboratory examination and analysis of synovial fluid aspiration.
During revision arthroplasty using a transfemoral approach soft tissues and bone showed an extensive metallosis which was debrided meticulously. Both prosthetic components were loose. After removal of the cup, parts of the Sulmesh coating remained integrated in the acetabular bone and were correspondingly missing on the back of the cup. Macroscopically no other reasons for this extensive metallosis were seen by analyzing the surfaces of the prosthetic head, the cup and also the taper.
The acetabulum was reconstructed by impaction grafting of the bone deficiencies, a Burch-Schneider antiprotrusio cage and a cemented UHMW-PE flat profile inlay. On the femoral side a cemented MS-30 stem was implanted. Tissue analysis showed that metallosis was caused exclusively by titanium debris.
This case shows that a delamination of the Sulmesh layer can be the cause of metallosis and prosthetic loosening.