Comparative Analysis between Short Stem and Conventional Femoral Stem in Patients with Osteonecrosis of Femoral Head: Metha Stem and Excia Stem.

Objective: To compare the intraoperative, radiological, and clinical short-term outcomes of cementless total hip arthroplasties (THA) using a short stem (SS) and a conventional femoral stem (CS) in a randomized prospective control study.

Methods: From June 2011 to October 2017, patients who underwent cementless THA for idiopathic osteonecrosis of the femoral head were recruited. Patients had a minimum 2 years of follow-up after the operation. The patients were divided into two groups: those who underwent THA using an SS and those who underwent THA using a CS. SS were used in 34 patients (41 hips) and CS were used in 41 patients (45 hips). In both groups, the same cup was used in all cases, and the mean follow-up periods were 63 (26-101) months in the SS and 64 (26-101) months in the CS groups. Intraoperative, clinical, and radiological evaluations were performed for the two groups.

Results: There was no difference in the demographics of the two groups. There was one patient with a proximal femoral crack in the SS group and one with a distal femoral crack in the CS group. Clinically, the mean Harris hip score was improved in both groups at 2-year follow-up. Radiographically endosteal osseointegrations were found in 40 of 41 cases in the SS group and in 44 of 45 cases in the CS group. There was one case of dislocation in each group. In the SS group, the acetabular cup was changed and repositioned 7 months after the initial operation. Stem loosening, infection, ceramic breakage, and varus/valgus change were not observed. There was a statistically significant lower stress shielding effect in the SS group. There were no differences in vertical/parallel offset and leg length discrepancy.

Conclusion: The intraoperative, radiological, and clinical evaluations in both groups showed good outcomes and there was no statistically significant difference between the two groups.