The Modular Universal Tumour And Revision System (MUTARS®) in endoprosthetic revision surgery

The aim of this study was to present the clinical and functional results of revision surgery after failed hip endoprostheses using the Modular Universal Tumour And Revision System (MUTARS (R)). Functional results of the hip endoprostheses were recorded by applying the Harris hip score. The extent of the presurgical radiological bone defect was measured according to the classification system of the German orthopaedic association (DGOOC). Indications for revision surgery on 45 patients (21 female, 24 male) were aseptic loosening (19 patients), infection (16 patients), or periprosthetic fracture (Vancouver classification B2, B3 and C, in nine patients). Revision surgery was performed after 8.6 years on average (min. 0.6; max. 14.25 years). Large defects of the proximal femur (80% medial or lateral diaphysis; 20% meta-diaphysis according to DGOOC classification) were adequately reconstructed. The average follow-up was 38.6 months. Complications occurred in eight patients: one luxation, two aseptic loosenings, and five reinfections were diagnosed. The Harris hip score (presurgical 30; postsurgical 78) showed significant improvement after revision surgery. Regarding the extent of the patients' bone defects, good functional results were achieved. The comparatively low number of luxations and loosenings is due to the high modularity of the prosthesis with arbitrary antetorsion in the hip joint. However, high reinfection rates in mega-implants still constitute a problem and should be the subject of further studies.