Many authors have described component position and leg length discrepancy (LLD) after total hip arthroplasty (THA) as the most important factors for good postoperative outcomes. However, regarding the relationships between component position and different approaches for THA, the optimal approach for component position and LLD remains unknown. The aims of this study were to compare these factors among the direct anterior, posterolateral, and direct lateral approaches on postoperative radiographs retrospectively, and determine which approach leads to good orientation in THA. We retrospectively evaluated 150 patients who underwent unilateral primary THA in our department between January 2009 and December 2014, with the direct anterior, posterolateral, or direct lateral approach used in 50 patients each. Patients with significant hip dysplasia (Crowe 3 or 4), advanced erosive arthritis, prevented osteotomy of the contralateral hip, and body mass index (BMI) of more than 30 were excluded. The mean age, sex, and preoperative diagnosis of the affected hip were equally distributed in patients who underwent THA with the different approaches. The mean BMI did not differ significantly among the groups. The radiographic measurements included cup inclination angle, dispersion of cup inclination from 40°, and LLD on an anteroposterior pelvic radiograph, and cup anteversion angle and dispersion of cup anteversion from 20° on a cross-table lateral radiograph postoperatively. We also measured the ratios of patients with both cup inclination of 30–50° and cup anteversion of 10–30° (target zone in our department), femoral stem varus/valgus, and LLD of 10 mm or less. Statistical analyses used an unpaired Introduction
Methods
We perform PAO via a modified Smith-Petersen approach. The purpose of this study was to investigate the result of PAO via a modified Smith-Petersen approach at a minimum 10-years' follow-up. We retrospectively reviewed 209 hips in 179 patients with acetabular dysplasia who underwent PAO with a modified Smith-Petersen approach from August 1995 to April 2010. Exclusion criteria were as follows: under 10 year follow-up, incomplete clinical or radiographic data. Harris hip score (HHS) was investigated preoperatively, at the time of most improvement and at the final follow-up for clinical evaluation. Tönnis classification was investigated preoperatively and at the final follow-up for evaluation of osteoarthritis. Center edge (CE) angle and acetabular roof obliquity (ARO) were investigated preoperatively, postoperatively and at the final-follow up for radiographic evaluation. Tönnis classification and radiographic parameters were investigated on anterior-posterior radiographs. Patients of conversion of PAO to total hip arthroplasty (THA) were investigated for preparing Kaplan Myer survival analysis. The Wilcoxon signed-rank test was used to compare changes in HHS and radiographic parameters between the preoperative and the postoperative values. Statistical significance was defined a priori as p < 0.05.Introduction
Methods
The Mayo-Stem is short and tapered in the anteroposterior and mediolateral directions, designed to enhance early fixation through multiple point contact in the proximal medullary cavity. The purpose of this study was to investigate the clinical and radiographic results of total hip arthroplasty (THA) using this short stem in younger patients. A total of 97 cementless THAs using this short stem were investigated. The length of the stem used ranged from 90mm to 110 mm. The average age of the patients at the time of surgery was 50.9 years (33–64 years). The average follow-up period was 64 months (38–108 months). The Harris hip score was used for clinical evaluation. The valgus angles of the stems and the changes in radiographic findings around the stems after surgery were investigated on the AP radiographs of hip. The average Harris hip score was 52.0 points pre-operatively and 93.9 points at the latest follow-up. An intraoperative femoral fissure fracture of the proximal femur occurred in 15 hips (15.4%), which were treated by circlage wires. The average valgus angle of the stem was 3.5° (range: −6°–18°). The development of bone trabeculae was seen around the curve of the stem (Gruen zones 3 and 5) in 79.4 % of hips one year after surgery. A radiolucent line was found on the lateral side of the stem (Gruen zones 1, 2, and 3) in 13.4 % of hips, which occurred in connection with the development of bone trabeculae. Subsidence of the stems (>
2mm) was seen in three hips in which intraoperative femoral fissure fracture had not occurred. These hips did not get the development of bone trabeculae. In two hips of the three hips, the valgus angles of the stems were 15° and 17° respectively. In the case of the third hip, the stem was small to the proximal femur. Overall the clinical result of THA using a short-stem was basically gratifying. The development of bone trabeculae, the stem size to the proximal femur and the stem position were important factors for the fixation of stem. Intraoperative fissure fracture treated by circlage wires and radiolucent lines with the development of bone trabeculae did not affect the fixation of stem.
