The Effect of Functional Pelvic Tilt on the Three-Dimensional Acetabular Cup Orientation in Total Hip Arthroplasty Dislocations

BackgroundAnterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-acetabular positions. This case-control study compares changes in 3-D acetabular cup orientation during functional pelvic tilt between posterior THA dislocations vs stable THAs.MethodsStanding and sitting 3-D cup orientation was compared between fifteen posterior dislocations vs 233 prospectively followed stable THAs. 3-D cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version, and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position.ResultsThe standing cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P = .039). Compared with the controls, from standing to sitting, they showed less posterior pelvic tilt (P < .001). This led to a significant lower coronal inclination (P < .001) and sagittal ante-inclination (P < .001) in the sitting position but similar transverse version (P = .366).ConclusionsComparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. By contrast, the transverse version was not significantly different in both positions. This confirms the importance of biplanar data on functional cup orientation.Level of EvidenceDiagnostic, Level III.     

Unrecognized Acetabular Component Rotation With Formation of a Pseudoarticulation After Total Hip Arthroplasty

We report an unusual case of an 82-year–old woman who presented with bilateral knee pain and advanced tibial-femoral and patellofemoral arthrosis. A preoperative total lower extremity film revealed an unrecognized, asymptomatic, dislocated right total hip arthroplasty with a rotated acetabular component that likely occurred 12 years earlier. The dislocated prosthetic femoral head appeared to be articulating with a pseudoacetabulum that had formed superiorly and laterally to the acetabular cup. The patient was unaware of any incident where she noticed an acute change after her hip arthroplasty surgery. We believed the patient to have a chronically dislocated hip that was pain free and quite functional for many years, an unusual condition that has not been reported previously in the literature.     

Contemporary Porous Titanium Acetabular Components for Total Hip Arthroplasty After Pelvic Radiation

BackgroundPatients undergoing primary total hip arthroplasty (THA) following pelvic radiation have historically had poor survivorship free of aseptic acetabular component loosening. However, several series have reported improved results with tantalum acetabular components. The purpose of this study is to assess implant survivorship, radiographic results, and clinical outcomes of contemporary, porous titanium acetabular components in the setting of prior pelvic radiation.MethodsWe retrospectively reviewed 33 patients (38 hips) with prior pelvic radiation between 2006 and 2016 who underwent primary THA. The mean overall pelvic radiation dose was 6300 cGy with a mean latency period to THA of 5 years. The most common acetabular component was Pinnacle (DePuy Synthes) in 76%. Eight-seven percent of cups were fixed with screws. The mean age at primary THA was 74 years, 76% were male, and the mean body mass index was 30 kg/m². Mean follow-up was 5 years.ResultsThe 10-year survivorship free of revision for aseptic loosening, free of any revision, and free of any reoperation were 100%, 89%, and 89%, respectively, when accounting for death as a competing risk. There were 3 revisions; one each for taper corrosion, recurrent dislocation, and infection. Radiographically, all cups had evidence of osteointegration and none had radiographic evidence of loosening. The mean Harris Hip Score improved from 50 to 84 postoperatively (P < .0001).ConclusionContemporary porous titanium acetabular components with supplemental screws provided excellent implant fixation in patients with prior therapeutic pelvic radiation. At 10 years, 100% of these components were free of revision for aseptic loosening and 100% were radiographically well-fixed.Level of EvidenceLevel IV, Therapeutic.     

Total Hip Arthroplasty Patients With Fixed Spinopelvic Alignment Are at Higher Risk of Hip Dislocation

Background

Sitting radiographs have been used as a pre-operative tool to plan patient-specific total hip arthroplasty (THA) component position that would improve hip stability. Previous work has demonstrated that spinal mobility may impact functional acetabular position when seated. We sought to determine whether patients who dislocate following THA have different sitting spinopelvic alignment or acetabular component orientation compared to patients who did not dislocate.

Patient Obesity Influences Pelvic Lift During Cup Insertion in Total Hip Arthroplasty Through a Lateral Transgluteal Approach in Supine Position

Background

Movement of the pelvis during implantation of total hip arthroplasty (THA) has a major influence on the positioning of the acetabular cup. Strong traction caused by retractors leads to iatrogenic pelvic lift and can thus be partly responsible for cup malpositioning. The objective of this study was to investigate such factors that influence pelvic lift.

Accurate Acetabular Component Orientation After Total Hip Arthroplasty Using an Acetabular Alignment Guide

Between February 2005 and August 2006, we recorded acetabular component orientation in 90 patients (100 hips) who underwent primary total hip arthroplasty (THA), to determine whether using an alignment guide ensures accurate acetabular positioning. In the alignment-guide group (46 patients; 48 hips), a guide was placed on the pelvis, a Kirschner wire (K-wire) was attached to the guide, and orientation of the acetabular component was confirmed by both the surgeon and an assistant. In the control group (44 patients; 52 hips), a K-wire was not used and the angle was confirmed by the surgeon alone. Radiographic acetabular component inclination and anteversion and computed tomography anteversion were determined. There was no significant difference in mean component orientation between the 2 groups. However, the SD was significantly smaller in the alignment-guide group, showing that consistent acetabular component orientation in primary THA is highly reproducible when an acetabular alignment guide with an attached K-wire is used.     

Efficacy of the Anatomical-Pelvic-Plane Positioner in Total Hip Arthroplasty in the Lateral Decubitus Position

Background

Total hip arthroplasty in the lateral position involves particularly large variance in the sagittal tilt of pelvis fixation, which affects the imprecision of the cup anteversion leading to poor outcomes. We have added an additional compression pad to an existing device, also to be used in the lateral position, but theoretically enabling fixation on the anatomical pelvic plane (APP) serving as the reference plane. The present study aims to evaluate the usefulness of this device in comparison with the conventional device.

Cementless Total Hip Arthroplasty With Modified Oblique Femoral Shortening Osteotomy in Crowe Type IV Congenital Hip Dislocation

Midterm results of cementless total hip arthroplasty in patients with Crowe type IV congenital dislocation of the hip were evaluated. A modified oblique subtrochanteric shortening osteotomy was used in all patients. A cylindrical femoral stem was used in all patients to stabilize the osteotomy. Mean follow-up was 82 months in 20 hips of 16 patients. Mean Merle D'Aubigné pain score increased from 2.52 to 5.65 points, function score improved from 4.0 to 5.3 points, and mobility score improved from 3.95 to 5.35. Mean greater trochanter height relative to the estimated hip center was 6.8 ± 2.0 cm preoperatively and − 1 ± 0.2 cm postoperatively. Complications were dislocations in 3 patients, which were successfully managed without redislocation and fracture of greater trochanter in 3 patients, which healed uneventfully in 2 but with residual Trendelenburg gait in one. Total hip arthroplasty with modified oblique subtrochanteric shortening osteotomy is an effective technique for the treatment for Crowe type IV hip dislocation.     

Prevalence of Sagittal Spinal Deformity Among Patients Undergoing Total Hip Arthroplasty

BackgroundThe important relationship between sagittal spinal alignment and total hip arthroplasty (THA) is becoming well recognized. Prior research has shown a significant relationship between sagittal spinal deformity (SSD) and THA instability. This study aims at determining the prevalence of SSD among preoperative THA patients.MethodsA multicenter database of preoperative THA patients was analyzed. Radiographic parameters measured from standing radiographs included anterior pelvic plane tilt, spinopelvic tilt, and lumbar lordosis (LL); pelvic incidence (PI) was measured from computed tomography scans. Lumbar flatback was defined as PI-LL mismatch >10°, balanced as PI-LL of −10° to 10°, and hyperlordosis as PI-LL <−10°.ResultsA total of 1088 patients were analyzed (mean, 64 years; 48% female). And 59% (n = 644) of patients had balanced alignment, 16% (n = 174) had a PI-LL > 10°, and 4% (n = 46) had a PI-LL > 20° (severe flatback deformity). The prevalence of hyperlordosis was 25% (n = 270). Flatback patients tended to be older than balanced and hyperlordotic patients (69.5 vs 64.0 vs 60.8 years, P < .001). Spinopelvic tilt was more posterior in flatback compared to balanced and hyperlordotic patients (24.7° vs 15.4° vs 7.0°) as was anterior pelvic plane tilt (−7.1° vs −2.0° vs 2.5°) and PI (64.1° vs 56.8° vs 49.0°), all P < .001.ConclusionOnly 59% of patients undergoing THA have normally aligned lumbar spines. Flatback SSD was observed in 16% (4% with severe flatback deformity) and there was a 25% prevalence of hyperlordosis. Lumbar flatback was associated with increasing age, posterior pelvic tilt, and larger PI. The relatively high prevalence of spinal deformity in this population reinforces the importance of considering spinopelvic alignment in THA planning and risk stratification.     

Complications After Revision Total Hip Arthroplasty in the Medicare Population

Background

The purpose of this study was to identify the incidence and types of complications after revision total hip arthroplasty (THA) within the first year, and determine the relative risk factors for these complications and of re-revision.

股骨粗隆下截骨短缩结合全髋置换术治疗高位先天性髋关节脱位

目的讨论股骨粗隆下截骨短缩结合全髋关节置换治疗先天性髋关节脱位的初步经验。方法本组7例高位先天性髋关节脱位,其中CroweⅢ型2例,CroweⅣ型5例。采用股骨粗隆下截骨短缩结合非骨水泥全髋关节置换术,其中5例进行了髋臼结构性植骨。术后随访Harris评分、肢体长度、步态、Trendelenburg征以及放射学改变。结果术后平均随访29.1个月,股骨截骨处及髋臼植骨均愈合,旋转中心平均下降53mm(39～63mm)。Harris评分由术前35.9分(32～42分)转为术后84.6分(68～96分);其中疼痛评分术前为14.3分(10～20分),术后为40.3分(30～44分)。屈髋活动度术前平均为85.7°(60°～125°),术后为84.3°(70°～100°)。1例Trendelenburg征术后持续阳性;2例术后出现股神经损伤表现,术后6周恢复。无感染、脱位、假体松动等并发症出现。结论短期随访表明,股骨粗隆下截骨短缩结合非骨水泥全髋关节置换术是治疗高位先天性髋关节脱位可靠有效的方法。     

A Reliable Femoral Osteotomy in Total Hip Arthroplasty for Hartofilakidis Type C Developmental Dysplasia of the Hip: Proximal Femoral Reconstruction

BackgroundProcedure of the femur is extremely challenging during total hip arthroplasty (THA) for Hartofilakidis type C developmental dysplasia of the hip. The main purpose of this study is to compare the clinical effectiveness of proximal femoral reconstruction (PFR) with subtrochanteric transverse osteotomy (STO).MethodsBetween 2006 and 2015, 33 primary THAs in 26 patients were performed with PFR and 16 hips in 13 patients underwent STO. The mean follow-up was 4.2 (range, 2.2-10.8) years in PFR group and 5.9 (range, 3.5-11.3) years in STO group. At the final follow-up, clinical scores and radiographic results were evaluated for 33 hips in PFR group and 15 hips in STO group.ResultsPostoperative Harris hip scores and implant position did not differ between the treatment groups. The mean length of the oblique osteotomy line at proximal femur was 6.9 cm (range, 5.8-7.6 cm) in PFR group. The amount of bone union occurred within 6 months after surgery was 24 (72.7%) hips in PFR group and 9 (60.0%) in STO group. Three major postoperative complications occurred in PFR group, and medial femoral calcar erosion was noted in 1 hip in STO group.ConclusionSimilar with STO, the clinical results of PFR technique are a reliable solution for femoral procedure during THA in patients with Hartofilakidis type C developmental dysplasia of the hip.     

Acetabular Component Position and the Risk of Dislocation Following Primary and Revision Total Hip Arthroplasty: A Matched Cohort Analysis

Background

Recently, the importance of acetabular component positioning in the Lewinnek “safe zone” in preventing prosthetic dislocation following total hip arthroplasty (THA) has been questioned. The purpose of this study was to determine the proportion of acetabular components within the Lewinnek safe zone between primary and revision THAs that have sustained a dislocation vs matched controls without a dislocation event.

Chronological Changes in Axial Alignment of the Ipsilateral Hip and Knee After Total Hip Arthroplasty

Background

Internal rotation of the hip and lateral patellar tilt increases after total hip arthroplasty (THA). However, it remains unknown whether these parameters change with time after the index THA.

The Impact of Total Hip Arthroplasty on Pelvic Motion and Functional Component Position is Highly Variable

Background

This study's purpose was to determine the impact of THA implantation on pelvic motion, and to assess motion in patients with a history of lumbar fusion or prosthetic dislocation.

Squatting After Total Hip Arthroplasty: Patient-Reported Outcomes and In Vivo Three-Dimensional Kinematic Study

BackgroundSquatting is an important function for many daily activities, but has not been well documented after total hip arthroplasty (THA). This study investigated the participation rate of squatting and in vivo kinematics during squatting.MethodsA survey questionnaire about squatting was mailed to patients who underwent primary THA and 328 patients returned acceptable responses. Additionally, 32 hips were evaluated for dynamic 3-dimensional kinematics of squatting using density-based image-matching techniques. Multivariate analyses were applied to determine which factors were associated with anterior liner-to-neck distance at maximum hip flexion.ResultsPatients who could easily squat significantly increased this ability postoperatively (23.5% vs 46%, P < .01). In 29.5% of the patients there was still no ability to squat after THA; the main reason was anxiety of dislocation (34.2%). Kinematic analysis revealed that maximum hip flexion averaged 80.7° ± 12.3° with 12.8° ± 10.7° of posterior pelvic tilt and 9.7 ± 3.0 mm of anterior liner-to-neck distance. Neither liner-to-neck, bone-to-bone, nor bone-to-implant contact was observed in any of the hips. Larger hip flexion and smaller cup anteversion were negatively associated with the anterior liner-to-neck distance at maximum hip flexion (P < .05).ConclusionPostoperatively, approximately 70% of patients squatted easily or with support. Anxiety of dislocation made patients avoid squatting after THA. In vivo squatting kinematics suggest no danger of impingement or subsequent dislocation, but excessively large hip flexion and small cup anteversion remain as risks.     

A Safe Zone for Acetabular Component Position in Metal-On-Metal Hip Resurfacing Arthroplasty: Winner of the 2012 HAP PAUL Award

A safe zone for acetabular component positioning in hip resurfacing (RAIL: Relative Acetabular Inclination Limit) was calculated based on implant size and acetabular inclination angle (AIA). For AIA below the RAIL, there were no adverse wear failures or dislocations, and only 1% of cases with ion levels above 10 μg/L. Other than high inclination angle and small bearing size, female gender was the only other factor that correlated with high ion levels in the multivariate analysis. Seven hundred sixty-one hip resurfacing cases are included in this study. The UCLA activity score, femoral shaft angle, body mass index, weight, American Society of Anesthesiologists score, combined range of motion, diagnosis, age, gender, implant brand, AIA, bearing size, and duration of implantation were analyzed to determine the potential risk factors for elevated metal ion levels. These findings apply to sub hemispheric metal-on-metal bearings with similar coverage arcs as the Biomet and Corin hip resurfacing brands. Additional problems may occur when these bearings are connected with trunions on stems for total hip arthroplasty.     

Comparison of Total Hip Arthroplasty With and Without Femoral Shortening Osteotomy for Unilateral Mild to Moderate High Hip Dislocation

Background

This study compares the outcome between THA with and without femoral shortening osteotomy for unilateral mild to moderate high hip dislocation in developmental dysplasia of the hip patients.

Standing Versus Supine Radiographs to Evaluate Femoral Head Penetration in the Polyethylene Liner After Total Hip Arthroplasty

The linear penetration rates for ceramic femoral heads on conventional and highly cross-linked polyethylene were measured and compared with radiographs taken in the standing and supine position taken three weeks postoperatively and at final follow-up. Seventy-five patients (83 hips) with conventional polyethylene (group-1) and two hundred and seventy five patients (300 hips) with highly cross-linked polyethylene (group-2) were studied. Follow-up periods were 14.5 years in group-1 and 8.6 years in group-2. The average penetration rates in group-1 were 0.17 mm/year in supine position and 0.18 mm/year in standing position (P < 0.05). On the other hand, the rates in group-2 were 0.03 mm/year and 0.04 mm/year respectively (P < 0.05). Although there were statistical differences between groups, 0.01 mm differences are probably not clinically relevant.