TABLE OF CONTENTS Case Study A
A housewife born in 1941 had a history of tuberculosis of the left hip. She had a fusion of her hip done in 1947 with limb length corrective surgery. It was done at the level of mid-shaft with a femoral plate, and the implant was secured to the site using screws. The implant was an 8-cm four-hole bone plate, with four 4-mm diameter screws, and 28 mm in length. The plate and screws were not removed until 1997 (50 years later), when the patient complained of thigh and knee pain with an associated swelling on the right side. Histology of the tissue surrounding the implant site showed features consistent with foreign body reaction. The fibrous tissue was observed to have deposits of a black foreign material. No malignancies were seen in the tissue specimens. In removing the plate, the proximal quarter with its two proximal screws had to be broken off to ease the removal of the implant. Figure 3 11(a) shows that one end of the plate was badly corroded, especially under the screw heads, while the screws and the other end of the plate were less affected. The X-ray image in Figure 3-11(b) reveals that the less corroded end of the plate was protected by an overgrown layer of bone; the remains of a drill bit accidentally left in the patient at the time of the original operation can also be seen. Analysis revealed that the plate was constructed from a ferritic stainless...
