This study aimed to investigate the incidence of ≥ 5 mm asymmetry in lower and whole leg lengths (LLs) in patients with unilateral osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH-OA) and primary hip osteoarthritis (PHOA), and the relationship between lower and whole LL asymmetries and femoral length asymmetry. In total, 116 patients who underwent unilateral total hip arthroplasty were included in this study. Of these, 93 had DDH-OA and 23 had PHOA. Patients with DDH-OA were categorized into three groups: Crowe grade I, II/III, and IV. Anatomical femoral length, femoral length greater trochanter (GT), femoral length lesser trochanter (LT), tibial length, foot height, lower LL, and whole LL were evaluated using preoperative CT data of the whole leg in the supine position. Asymmetry was evaluated in the Crowe I, II/III, IV, and PHOA groups.Aims
Methods
This study aimed to develop and validate a fully automated system that quantifies proximal femoral bone mineral density (BMD) from CT images. The study analyzed 978 pairs of hip CT and dual-energy X-ray absorptiometry (DXA) measurements of the proximal femur (DXA-BMD) collected from three institutions. From the CT images, the femur and a calibration phantom were automatically segmented using previously trained deep-learning models. The Hounsfield units of each voxel were converted into density (mg/cm3). Then, a deep-learning model trained by manual landmark selection of 315 cases was developed to select the landmarks at the proximal femur to rotate the CT volume to the neutral position. Finally, the CT volume of the femur was projected onto the coronal plane, and the areal BMD of the proximal femur (CT-aBMD) was quantified. CT-aBMD correlated to DXA-BMD, and a receiver operating characteristic (ROC) analysis quantified the accuracy in diagnosing osteoporosis.Aims
Methods
Pelvic incidence (PI) is considered an important anatomical parameter for determining the sagittal balance of the spine. The contribution of an abnormal PI to hip osteoarthritis (OA) remains controversial. In this study, we aimed to investigate the relationship between PI and hip OA, and the difference in PI between hip OA without anatomical abnormalities (primary OA) and hip OA with developmental dysplasia of the hip (DDH-OA). In this study, 100 patients each of primary OA, DDH-OA, and control subjects with no history of hip disease were included. CT images were used to measure PI, sagittal femoral head coverage, α angle, and acetabular anteversion. PI was also subdivided into three categories: high PI (larger than 64.0°), medium PI (42.0° to 64.0°), and low PI (less than 42.0°). The anterior centre edge angles, posterior centre edge angles, and total sagittal femoral head coverage were measured. The correlations between PI and sagittal femoral head coverage, α angle, and acetabular anteversion were examined.Aims
Methods
The purposes of this study were to evaluate the accuracy and feasibility of a robotic preparation for acetabular metal augments in patients with developmental dysplasia of the hip (DDH). Mako robotic arm reaming was used in 7 DDH to prepare the bony cavities for both Trident PSL cups and Tritanium acetabular wedge augments in six hips with Crowe 2 or 3 DDH. In CT-based planning, a properly sized cup was placed in the original acetabulum, and the same sized cup was also placed to fit the superolateral acetabular defect. The coordinates of the planned positions of cup and augment were recorded to manage the robotic arm reaming. After registration of the patient's pelvis, robotic reaming was performed first for the augment, then, for the cup by changing the target position of reaming as planned. The accuracy of the cup and augment placement was assessed on postoperative CT. To evaluate the feasibility of the robotic procedure, the OR time and blood loss were compared with those of 13 patients who received the same cup and augment systems with a conventional technique. All procedures were done without fracture or fixation failure. There were no differences in OR time or blood loss between the two procedures. Postoperative CT measurements of the distance between the cup center and the augment sphere center showed less than 2mm difference from the Mako preoperative planning. Although a longer time of follow up evaluation is mandatory, our robotic acetabular augment preparation technique is accurate and feasible.
The aim of this study was to examine whether hips with unilateral osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH) have significant asymmetry in femoral length, and to determine potential related factors. We enrolled 90 patients (82 female, eight male) with DDH showing unilateral OA changes, and 43 healthy volunteers (26 female, 17 male) as controls. The mean age was 61.8 years (39 to 93) for the DDH groups, and 71.2 years (57 to 84) for the control group. Using a CT-based coordinate measurement system, we evaluated the following vertical distances: top of the greater trochanter to the knee centre (femoral length GT), most medial prominence of the lesser trochanter to the knee centre (femoral length LT), and top of the greater trochanter to the medial prominence of the lesser trochanter (intertrochanteric distance), along with assessments of femoral neck anteversion and neck shaft angle.Aims
Patients and Methods
The purposes of this study were to review retrospectively the 10-year outcome of cementless total hip arthroplasty (THA) using an active robot system in the femoral canal preparation for an anatomic short stem and navigation in the cup placement through a mini incision posterior approach. We reviewed all patients who underwent THA with this procedure in 53 hips between 2004 and 2007. There were no intraoperative fracture nor navigation- or robotic-related complications. All implant sizes were same as planned ones. All cases were followed up at least two years and all implants showed bone ingrowth stable according to the Engh's criteria. After then, six patients died of unrelated causes. Two patients (three hips) could not come to the 10-year follow-up examination. The remaining 44 hips were followed for 10 to 12 years (11 years on average). There is no dislocation. The average JOA hip score improved from 48 preoperatively to 96 at the final examination. On the postoperative x-ray measurements, the average cup radiographic inclination was 39° and the radiographic anteversion was 14°. There was no stem which showed more than 2° of varus or valgus alignment. There was no case who showed more than 5mm of limb length discrepancy. Postoperative CT images of 38 hips were obtained at 2 weeks. After matching the coordinates of the pelvis and femur with the preoperative planning, we got very small differences in alignment parameters between the measured values and the planed ones. The difference differences between the plan and measured values were −0.1° in cup inclination, −1.4° in cup anteversion, stem 0.5° in coronal alignment, 0.6° in stem sagittal alignment, and −1.6° in stem anteversion, respectively. We conclude that our robotic femoral preparation for a short anatomical stem and navigated cup placement thru a mini-posterior approach was safe and feasible without affecting the accuracy of the procedure. There were no long term adverse effect of the procedure.
To confirm whether developmental dysplasia of
the hip has a risk of hip impingement, we analysed maximum ranges
of movement to the point of bony impingement, and impingement location
using three-dimensional (3D) surface models of the pelvis and femur
in combination with 3D morphology of the hip joint using computer-assisted methods.
Results of computed tomography were examined for 52 hip joints with
DDH and 73 normal healthy hip joints. DDH shows larger maximum extension
(p = 0.001) and internal rotation at 90° flexion (p <
0.001).
Similar maximum flexion (p = 0.835) and external rotation (p = 0.713)
were observed between groups, while high rates of extra-articular
impingement were noticed in these directions in DDH (p <
0.001).
Smaller cranial acetabular anteversion (p = 0.048), centre-edge
angles (p <
0.001), a circumferentially shallower acetabulum,
larger femoral neck anteversion (p <
0.001), and larger alpha
angle were identified in DDH. Risk of anterior impingement in retroverted
DDH hips is similar to that in retroverted normal hips in excessive
adduction but minimal in less adduction. These findings might be
borne in mind when considering the possibility of extra-articular
posterior impingement in DDH being a source of pain, particularly
for patients with a highly anteverted femoral neck. Cite this article:
We investigated differences in the location and
mode of labral tears between dysplastic hips and hips with femoroacetabular
impingement (FAI). We also investigated the relationship between
labral tear and adjacent cartilage damage. We retrospectively studied
72 symptomatic hips (in 68 patients: 19 men and 49 women) with radiological
evidence of dysplasia or FAI on high-resolution CT arthrography.
The incidence and location of labral tears and modes of tear associated
with the base of the labrum (Mode 1) or body of the labrum (Mode
2) were compared among FAI, mildly dysplastic and severely dysplastic
hips. The locations predominantly involved with labral tears were
different in FAI and mild dysplastic hips (anterior and anterosuperior
zones) and in severely dysplastic hips (anterosuperior and superior
zones) around the acetabulum. Significant differences were observed
in the prevalence of Mode 1 Hip pathology is significantly related to the locations and modes
of labral tears. Mode 1 tears may be a risk factor for the development
of adjacent acetabular cartilage damage. Cite this article:
The long-term results of grafting with hydroxyapatite granules for acetabular deficiency in revision total hip replacement are not well known. We have evaluated the results of revision using a modular cup with hydroxyapatite grafting for Paprosky type 2 and 3 acetabular defects at a minimum of ten years’ follow-up. We retrospectively reviewed 49 acetabular revisions at a mean of 135 months (120 to 178). There was one type 2B, ten 2C, 28 3A and ten 3B hips. With loosening as the endpoint, the survival rate was 74.2% (95% confidence interval 58.3 to 90.1). Radiologically, four of the type 3A hips (14%) and six of the type 3B hips (60%) showed aseptic loosening with collapse of the hydroxyapatite layer, whereas no loosening occurred in type 2 hips. There was consolidation of the hydroxyapatite layer in 33 hips (66%). Loosening was detected in nine of 29 hips (31%) without cement and in one of 20 hips (5%) with cement (p = 0.03, Fisher’s exact probability test). The linear wear and annual wear rate did not correlate with loosening. These results suggest that the long-term results of hydroxyapatite grafting with cement for type 2 and 3A hips are encouraging.
We compared a modular neck system with a non-modular system in a cementless anatomical total hip replacement (THR). Each group consisted of 74 hips with developmental hip dysplasia. Both groups had the same cementless acetabular component and the same articulation, which consisted of a conventional polyethylene liner and a 28 mm alumina head. The mean follow-up was 14.5 years (13 to 15), at which point there were significant differences in the mean total Harris hip score (modular/non-modular: 98.6 (64 to 100)/93.8 (68 to 100)), the mean range of abduction (32° (15° to 40°)/28 (0° to 40°)), use of a 10° elevated liner (31%/100%), the incidence of osteolysis (27%/79.7%) and the incidence of equal leg lengths (≥ 6 mm, 92%/61%). There was no disassociation or fracture of the modular neck. The modular system reduces the need for an elevated liner, thereby reducing the incidence of osteolysis. It gives a better range of movement and allows the surgeon to make an accurate adjustment of leg length.
