Intrapelvic pin migration after periacetabular reconstruction and arthroplasty of the hip in metastatic pelvic disease—a case report

Abstract

In January 1997, a 62-year-old man was diagnosed with a hypernephroma of the right kidney and bilat-eral pulmonary metastases. He underwent a right nephrectomy as initial surgery. Histology showed a 16-mm granular cell renal carcinoma of the lower part of the right kidney. He received chemotherapy with α-interferon for the following 11 months. In November 1999, CT showed a 4-cm osteolytic lesion from the right posterior inferior iliac spine to the roof of the acetabulum. The medial and lat-eral bony borders were partially destroyed and the lesion was therefore classified as class III accord-ing to Harrington (1981).The patient underwent local radiation therapy in December 1999, and a second course of chemo-therapy with vinblastine. Immune modulation ther-apy with α-interferon showed a partial remission of the pulmonary metastases. In addition, he received intravenous treatment with bisphosphonates. In February 2000, the patient sustained a patho-logical fracture of the right iliac wing with medial and cranial dislocation of the entire acetabulum.A second course of radiation therapy was given in August 2000. In April 2001, the patient presented with an advanced right periacetabular fracture (Figure 1). A periacetabular reconstruction and a total hip arthroplasty was performed. A reinforcement cage (Burch-Schneider, Protek, Switzerland) was com-bined with a cemented standard stem with a 28-mm metal ball head and cemented polyethylene inlay. After reduction of the fracture, structural continu-ity was achieved and reinforced with 3 Steinmann pins using the compound osteosynthesis tech-nique, i.e. the pins were entirely covered with bone cement, which filled the gap. 1 pin was inserted from the superior iliac crest to the cranial part of the acetabulum, and 2 pins through the center of the acetabulum. One of these pins was unthreaded (Figure 2). The pins were cut off flush with the iliac crest.The patient quickly regained pain-free walking using 2 crutches. At routine follow-up (6 months), he was satisfied with the functional result (Figure 3).In November 2001, the patient suffered an epi-sode of transient hematuria and was treated under the suspicion of urinary tract infection. An abdomi-nal sonography showed mild hepatic steatosis but no other abnormalities. 9 months after surgery, a routine pelvic radiograph (Figure 4) showed migration of one of the Steinmann pins. A CT scan was performed, which showed the dislocation of the pin into the pelvic cavity very close to the blad-der, the anterior side of the rectum and the prostate (Figure 5). There was no sign of any penetration of the neighbouring organs. The dislocated pin was removed under general anesthesia by a modified ilio-inguinal approach without difficulty. The his-tological findings showed no signs of local tumor