Pseudotumor and repeated dislocation after total hip arthroplasty with ceramic-on-metal bearing: a case report.

Pseudotumor is a rare complication following total hip arthroplasty (THA) with ceramic-on-metal (CoM) bearings. There is still in controversy about the using of CoM bearings when conducting surgery. We reported a case of a 47-year-old woman who underwent cementless CoM bearing THA because of left Crowe type III dislocation of the hip (DDH) in December 2009. One year after THA, she presented at our hospital complaining of crunching noise, pain, and decreased level of function. A revision surgery was performed because of left hip instability in December 2010, we adjusted the excessive anteversion of stem and replaced the head by using the long-neck ceramic head. In February 2019, she was admitted to our hospital complaining of repeated dislocation and fracture of greater trochanter. During the re-revision surgery, a pseudotumor and grey synovial sac were revealed. The metal liner was replaced with a ceramic liner and the greater trochanter was reattached using the Cable-Ready system. Clinical outcome was successful at 6 months postoperatively. This case vividly demonstrated CoM bearing should be avoided in THA. The pseudotumor highly destructed the periprosthetic soft tissues and the bone, which leaded to dislocation and periprosthetic fracture. The surgeon should be aware of the complication so that prompt diagnosis and treatment can be performed.