Fracture of hydroxyapatite coated prostheses: a report of two cases of stem failure in hip hemiarthroplasty

Hydroxyapatite (HA)-coated implants for hemiarthroplasty for fractures of the femoral neck offer the advantages of stable and permanent fixation. Since April 1994, we have treated 562 patients using the JRI Furlong HA-coated hemiarthroplasty system at the Worthing and Southlands Hospitals. Fracture of the fully-HA-coated stainless steel stem was seen in two patients. To our knowledge, this complication has not been reported in the literature. In both cases, the stem was well bonded distally and was loose proximally. The possible causes of stem fracture in these two cases could be related to stress shielding and the use of stainless steel implants. In addition, the junction between the wide proximal and narrow distal part might have served as a weak spot. We would advise surgeons to be aware of the complication of stem failure while using an HA-coated implant for hemiarthroplasty for femoral neck fracture in an active patient.