zimmer modular revision stem failure on total hip arthroplasty due to stem fracture from cone taper stem junction

The incidence of zimmer modular revision (zmr) hip system fractures is rare. the materialof the component decreases the risk of corrosion which titanium-based modular would lowerthe degree of degradation despite cold welding of the component. in this case presentation,we will discuss 2 cases of implant failure from the cone taper junction of the stem and discussthe susceptible causes of the failure. the new generation of surgery products has numeroussuccessful outcomes and has facilitated the way for modern orthopedic surgeons. despite thehigh rate of satisfying results, reports of implant failure are rare. we present 2 patients in similarsituations referring to the same model implant failure. it can be noticed that the force tolerancebecause of their weight might be a risk factor and some other factors may be missed, includingproviding sufficient distal bone support for the implant.