Relatively High Complication and Revision Rates of the Mayo^® Metaphysical Conservative Femoral Stem in Young Patients.

Abstract

The Mayo metaphysical conservative femoral stem (Zimmer, Warsaw, Indiana) is a wedge-shaped implant designed to transfer loads proximally, reduce femoral destruction, and enable the preservation of bone stock in the proximal femur. Thus, it is a potentially preferred prosthesis for active, non-elderly patients who may require additional future surgeries. This retrospective case study analyzed the outcomes of consecutive patients who underwent total hip replacements with this stem between May 2001 and February 2013. All patients underwent clinical assessment, radiological evaluation for the presence and development of radiolucent lines, and functional assessment (numerical analog scale, Harris hip score, and Short Form-12 questionnaire). Ninety-five hips (79 patients) were available for analysis. The patients' mean age was 43 years (range, 18-64 years), and the mean follow-up was 97 months (range, 26.9-166 months). The postoperative clinical assessments and functional assessments revealed significant improvements. Sixteen patients (20.3%) had 18 orthopedic complications, the most common of which were an intraoperative femoral fracture and implant dislocation requiring revision surgeries in 10 hips (10.5%). Radiological analysis revealed evidence of femoral remodeling in 64 (67.4%) implants, spot welds (neocortex) in 35 (36.8%), and osteolysis in 3 (3.2%). These results suggest that the conservative hip femoral implant has an unacceptable complication rate for non-elderly patients. [Orthopedics. 2018; 41(4):e516-e522.].