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INTRODUCTION: Osteolysis around the prosthesis following total hip arthroplasty (THA) is usually expanded slowly in the mid to long term, not progressive in the short term. Hematoma around the prosthesis is a rare phenomenon after a period of 1 year or more after surgery other than metal on metal THA. In addition, there are no studies reporting that hydroxyapatite (HA) itself has a possibility to cause osteolysis or hematoma after THA. This case has a particular disease phenomenon with three unusual factors, such as progressive osteolysis, hematoma, and HA debris in granulation tissue, following revision THA. CASE REPORT: A 79-year-old woman with pain in the left hip joint underwent a revision THA, using HA mesh and ultra high molecular weight polyethylene fiber cable for impaction bone grafting to fill a bone defect in the proximal femur in 2011. There were no abnormal findings clinically or on radiograph until 2014. Moderate osteolysis was observed at the lesser trochanter and the area distal to the greater trochanter on the radiograph in 2015. The synovial fluid culture was negative. On magnetic resonance imaging examination, the margin showed a low-density shell in both the T1- and T2-weighted images, and the inside was a mosaic mass, with mixed low- and high-density are as extending in a multidirectional manner. During surgery, cystic mass covered with a thick membrane was found around the artificial hip joint, and the inside of the capsule was full of solid and fluid hematoma and dark blood. There was no apparent wear and tear debris of the implant. On pathological examination, evidence of chronic hematoma, granulation tissue, and HA debris, interspersed inside the granulation tissue were observed. CONCLUSION: We experienced an extremely rare case with osteolysis and hematoma that progressively expanded in a short period of time after revision THA using HA mesh, which seemed to be caused by, crushed HA and resulted in osteolysis accompanied by hematoma. This case revealed that HA it has a possibility to cause osteolysis or hematoma after THA.
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A 6-field technique using lateral beams in conformal radiotherapy was developed for patients with bilateral supraclavicular lymph node metastasis of lung cancer. The possibility of using this technique in practice was evaluated. Six fields with the same isocenter point (IP) were arranged. Two fields using anterior-posterior opposed beams involved all of the planning target volume (PTV). The next 2 fields using off-cord oblique beams involved the PTV inferior to the IP. The remaining 2 fields using lateral opposed beams, that shielded the spinal cord, involved the PTV superior to the IP. The oblique 2 fields and lateral 2 fields were connected using a half-beam technique. In 6 patients with non-small-cell lung cancer (NSCLC, n = 4) or small-cell lung cancer (SCLC, n = 2), treatment re-planning based on this technique was performed. This technique was applicable in 4 patients with NSCLC, in whom the general criteria of radiotherapy for lung cancer were met. In 2 patients with SCLC, the cumulative volume of lung that received more than 20 Gy exceeded 37% of the total lung volume. This technique was usable in 67% of the patients and was not necessarily contraindicated in the other 33%.