Patient presentation: At 67 years of age, Evelyn had been in constant pain due to the failure of her two previous hip replacements. Suffering from developmental hip dysplasia her whole life, Evelyn underwent her first hip replacement at age 37 years. This was revised at age 52 years when a new plastic liner was inserted. Polyethylene wear debris from the two previous hip replacements had caused loosening of the cementless shell which was causing the pain in Evelyn’s left hip. The walls of the hip socket were also very thin due to bone loss.
Treatment and rationale: Evelyn’s surgeon recommended an Ossis custom acetabulum implant to overcome the significant defect and restore the acetabulum allowing an acetabulum cup component to be cemented in place.
How: CT scan data were used to develop a patient-specific 3D model, which was used to create an implant to improve the patient’s anatomy. Initial fixation was obtained using seven strategically-placed locking screws at locations determined by computer modeling of Evelyn’s hip anatomy. The screws were manufactured into flanges (four superior to the acetabulum passing through the shell into the ilium, and three inferior to the acetabulum, placed into the ischium and pubic ramus). Secondary fixation was via osseointegration with the porous mesh of the prosthesis. The implant was manufactured entirely from implant-grade titanium alloy. The modification consisted of removal of the HA coating which could absorb in situ and cause a breakdown in bond between the cement and cup.
Outcomes: The surgery went well and Evelyn was able to leave hospital just four days after the operation. Looking well, Evelyn was able to enjoy her garden at home and was very grateful to be pain free. She was looking forward to spending time with her family and getting back into her gardening.