Total hip arthroplasty using a short stem Stem design, position and size influence the development of bone trabeculae and appearance of radiolucent lines around the stem

Background The purpose of this study was to investigate the clinical and radiographic results of total hip arthroplasty (THA) using a short cementless stem. Methods A total of 106 cementless THAs using this short stem were investigated. The length of the stems ranged from 90-110mm. The average age of the patients at the time of surgery was 50.9 years. The average follow-up period was 64 months. The Harris Hip Score was used for clinical evaluation. The valgus angles of the stems and changes in radiographic findings around the stem after surgery were retrospectively reviewed on anteroposterior radiographs of the hip. Results The average preoperative and postoperative Harris Hip Scores were 52.0 and 93.9, respectively. The average valgus angle of the stems was 2.8 +/- 3.91. Bone trabeculae development was observed around the curve of the distal one-third of the stems in 87 hips. Radiolucent lines around the stems were seen in 29 hips. Stem subsidence of more than 2mm was observed in three hips where intraoperative femoral fractures had not occurred. The valgus angles of these three stems were 12 degrees, 13 degrees and - 8 degrees. In the third hip, the inserted stem was small relative to the proximal femur. These three hips did not exhibit any development of bone trabeculae but did show radiolucent lines. Conclusions Clinical results of THA using a short stem were generally satisfactory. The stem position and size were important for the bone trabeculae development and to prevent stem subsidence with radiolucent lines.