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

Abstract

ObjectiveTo 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.MethodsFrom 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.ResultsThere 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.ConclusionThe intraoperative, radiological, and clinical evaluations in both groups showed good outcomes and there was no statistically significant difference between the two groups.

Future of total hip arthroplasty with the Metha short stem in modern surgeries

“…In our material, 23 procedures (12.6%) of hip arthroplasty with Metha stem were performed for sterile necrosis of the femoral bone head. Our results are similar to those of the above-mentioned studies and fully confirm the reports of other authors 32 – 34 .…”

No significant differences in 60‐day postoperative complication rates between conventional and shortened stems

“…A recent study on the Dutch Arthroplasty Register [39] analysed 228,917 cementless conventional stems and 3,352 cementless short stems and found no significant differences in 10‐year stem revision rates (2.3% vs 3.0%), although today’s predominant short stems (Fitmore and Optimys) had lower revision rates than other less frequently used short stems (4.5%). In addition, prior clinical studies comparing conventional versus short stems found no significant differences in subsidence (0% vs 0% [19, 22]; 1% vs 0% [16]; 0% vs 2%, p = 0.554 [36]) or misalignment (0% vs 0% [19]; 2% vs 4%, p = 0.313 [36]; 1% vs 5%, p = 0.111 [13]); however, these clinical studies were underpowered to detect significant differences across groups. Based on this data, the present study performed an a priori sample size calculation to determine the number of patients that would be needed in each group to provide a significant difference in subsidence and misalignment.…”

“…In contrast, radiographic outcomes were not widely evaluated; three systematic reviews reported contradictory findings regarding bone mineral density [23, 43, 44], while one systematic review reported no significant differences in femoral offset and limb length discrepancy [12]. A number of comparative clinical studies have reported radiographic outcomes of conventional versus short stems, with cohorts varying between 25–132 per group [13, 16, 19–22, 36, 37, 42], which may be underpowered to detect significant differences across groups, considering the small incidence of subsidence (0–2%) and misalignment (0–5%) [13, 16, 19, 22, 36]. In terms of subsidence, Kato et al [16] reported only one case ≥ 2 mm in the conventional group and Shin et al [36] reported only one case ≥ 2 mm in the short group, while Lacko et al [22] and Kim et al [19] reported no cases ≥ 2 mm and ≥ 3 mm respectively in either group.…”

“…A number of comparative clinical studies have reported radiographic outcomes of conventional versus short stems, with cohorts varying between 25–132 per group [13, 16, 19–22, 36, 37, 42], which may be underpowered to detect significant differences across groups, considering the small incidence of subsidence (0–2%) and misalignment (0–5%) [13, 16, 19, 22, 36]. In terms of subsidence, Kato et al [16] reported only one case ≥ 2 mm in the conventional group and Shin et al [36] reported only one case ≥ 2 mm in the short group, while Lacko et al [22] and Kim et al [19] reported no cases ≥ 2 mm and ≥ 3 mm respectively in either group. In terms of misalignment, Kim et al [19] reported no cases ≥ 5° in either group, while Shin et al [36] reported 2 versus 1 case ≥ 5° in the short and conventional groups respectively ( p = 0.554).…”

“…In terms of subsidence, Kato et al [16] reported only one case ≥ 2 mm in the conventional group and Shin et al [36] reported only one case ≥ 2 mm in the short group, while Lacko et al [22] and Kim et al [19] reported no cases ≥ 2 mm and ≥ 3 mm respectively in either group. In terms of misalignment, Kim et al [19] reported no cases ≥ 5° in either group, while Shin et al [36] reported 2 versus 1 case ≥ 5° in the short and conventional groups respectively ( p = 0.554).…”