Background: The patient who suitable for short stem THA must has good neck quality for initial stable fixation. In Thailand, the majority of patients are end stage osteonecrosis and have relatively narrow neck diameter so it’s may be increased risk of intraoperative femoral fractures and leading to stem failure.
Objective: Evaluate the initial clinical and radiographic results of short stem THA over a maximum follow-up period of about 24 months, paying special attention to early problem.
Material and Method: The case series of 50 patients receiving short stem THA during March 2010 to September 2011. There were 15 cases of Mayo stem and 35 cases of Metha stem. The appearance of bone trabeculae development and radiolucent line at 1 year postoperative was reviewed using Gruen’s classification. The Harris hip score was recorded at 6 months, 12 months and 24 months postoperative for evaluated the clinical results.
Results: In Mayo stem group, the mean age of patient was 44.2 years (range, 19-58) with the mean BMI of 20.9 (range, 16.9-
28.1). There were 2 cases of intraoperative fractures and were treated with cerclage wires, 1 case had 3 mm subsidence with radiolucent line in zone 1, 2. Bone trabeculae was developed at zone 2 (60%), 6 (86.7%), 7 (53.3%) and radiolucent line was observed at zone 1 (6.7%) and zone 2 (6.7%). In Metha stem group, the mean age of patient was 43.9 years (range, 24-59) with the mean BMI of 22.2 (range, 16.5-32.3). There was 1 case of intraoperative fracture and was treated with cerclage wire, no further subsidence was observed. Bone trabeculae was developed at zone 1 (15.4%), 3 (79.9%), 6 (100%), 7 (92.3%) and no radiolucent line was observed. The mean Harris hip score was significantly improved from 44.9 (range, 22.7-59.7) preoperatively to 95.9 (range, 87-100) at 6 months (p < 0.01) in both stem design.
Conclusion: The clinical results of short stem THA are generally satisfactory. The short term results are promising and the learning curve acceptable. Its design enable preservation of the bone stock and the bone trabeculae appears to confirm the assumption of proximal force transmission. It is a promising option for young and active patients.

Keywords: Arthroplasty, Hip, Short stem