A Comparison of Radiographic Outcomes After Total Hip Arthroplasty Between the Posterior Approach and Direct Anterior Approach With Intraoperative Fluoroscopy

Background

Radiographic outcomes after total hip arthroplasty (THA) have been linked to clinical outcomes. The direct anterior approach (DAA) for THA has been criticized by some for providing limited exposure and compromised implant position but allows for routine use of intraoperative fluoroscopy. We sought to determine whether radiographic measurements differed by THA approach using prospective cohorts.

Decreased accuracy of acetabular cup placement for imageless navigation in obese patients

Background

Optimal acetabular cup position is an important determinant of the success of total hip arthroplasty (THA), and navigation systems have been developed and applied to improve placement precision. However, the registration method touching bony landmarks through soft tissues may decrease the accuracy in obese cases and in patients with acetabular dysplasia.

Methods

Placement accuracy in 69 joints in which THA was performed with imageless navigation was calculated by comparing the placement angle in the anterior pelvic plane and the placement angle in the x-ray table plane with the patient in the supine position. We defined the difference between the placement angle in the anterior pelvic plane and the angle displayed on the navigation screen as the error and the difference between the placement angle in the plane of the x-ray table and the target angle of acetabular component position as the difference in target angle. Patients were divided into obese (BMI ≥ 25) and nonobese (BMI < 25) groups and into acetabular dysplasia and nondysplasia groups.

Results

The mean ± SD navigation errors for all cases were 2.4° ± 2.0° for inclination and 3.7° ± 2.3° for anteversion. The mean difference in target angle for all cases was 2.8° ± 2.5° for inclination and 4.2° ± 3.0° for anteversion. The error in anteversion was significantly higher in the obese group (4.8° ± 2.5°) than in the nonobese group (3.2° ± 2.6°) (P = 0.01). No significant difference was observed between the acetabular dysplasia and nondysplasia groups.

Conclusions

Imageless navigation can be performed with an error of approximately 3° at the anterior pelvic plane. However, accuracy was found to decrease in obese cases.     

Acetabular reconstruction with the Kerboull-type plate at mid-term follow-up: survivorship analysis and prognostic factors for loosening

Introduction

Successful reconstruction during total hip arthroplasty for acetabular bone defects remains challenging. The purpose of our study was to evaluate clinical and radiographic results and performed a survivorship analysis for patients with acetabular bone loss undergoing total hip arthroplasty (THA) or revision THA using Kerboull-type acetabular reinforcement device(KT plate). Additionally, some independent prognostic factors for radiographic failure were identified.

Methods

A retrospective cohort study was conducted. Thirty patients (36 hips) were available for follow-up examination between 1997 and 2012, with a mean follow-up period of 10 years. We evaluated clinical and radiographic results. The mean patient age at the time of the operation was 66 years.

Results

Failure occurred in 6 cases, and further revisions were required for 2 hips. With failure for any reason as an endpoint, the cumulative survival at 10 years was 85%. Survival analysis at 10 years with failure as the endpoint revealed that the inclination angle of the KT plate ≤ 45° group showed higher survivorship than the inclination angle > 45° group (95.8 vs. 63.6%, P = 0.0047).

Conclusions

With a mean follow-up of 10 years, the clinical and radiographic outcomes were satisfactory. While this study group was small, the results suggest that prosthesis longevity may be improved by setting the inclination angle of this reinforcement device at ≤ 45°.

     

Medial placement of the acetabular component in an alumina-on-alumina total hip arthroplasty: a comparative study with propensity score matching

Purpose

In an alumina-on-alumina total hip arthroplasty (THA), recommended with a small inclination angle <45°, the acetabular component (cup) may be positioned more medially to be covered almost completely by host bone. The purpose of this study was to identify the correlating factors and to evaluate the outcomes of medial placement of the cup in patients with alumina-on-alumina THAs.

Methods

Using the propensity score matching with age, gender, body mass index, initial diagnosis, and the length of follow-up as variables, 38 hips with a medialized cup and 38 hips with a non-medialized one were identified from 389 hips in 347 who patients underwent primary alumina-on-alumina THA and followed up for more than 7 years. Clinical and radiological outcomes were compared between the two groups.

Results

Preoperative acetabular medial wall thickness and the cup inclination angle were significantly smaller in the medialization group compared to the non-medialization group. Center edge angle, cup size, and coverage by host bone were not significantly different between the two groups. The hip center of rotation was significantly medialized in the medialization group. The Harris hip scores were not significantly different between the two groups. No component loosening or osteolysis was observed and no revision was required in either groups.

Conclusions

Thin acetabular medial wall and a small inclination angle of the cup were the correlating factors of medial placement of the cup in patients who underwent an alumina-on-alumina THA. Medial placement did not lead to differences in the clinical or radiological outcomes.     

Total Hip Arthroplasty in the Spinal Deformity Population: Does Degree of Sagittal Deformity Affect Rates of Safe Zone Placement,Instability, or Revision?

Background

Changes in spinal alignment and pelvic tilt alter acetabular orientation in predictable ways, which may have implications on stability of total hip arthroplasty (THA). Patients with sagittal spinal deformity represent a subset of patients who may be at particularly high risk of THA instability because of postural compensation for abnormal spinal alignment.

Cementless Total Hip Arthroplasty for Patients with Crowe Type III or IV Developmental Dysplasia of the Hip: Two-Stage Total Hip Arthroplasty Following Skeletal Traction after Soft Tissue Release for Irreducible Hips

Background

Total hip arthroplasty (THA) for severe developmental dysplasia of the hip (DDH) is a technically demanding procedure for arthroplasty surgeons, and it is often difficult to reduce the hip joint without soft tissue release due to severe flexion contracture. We performed two-stage THAs in irreducible hips with expected lengthening of the affected limb after THA of over 2.5 cm or with flexion contractures of greater than 30 degrees in order to place the acetabular cup in the true acetabulum and to prevent neurologic deficits associated with acute elongation of the limb. The purpose of this study is to evaluate the outcomes of cementless THA in patients with severe DDH with a special focus on the results of two-stage THA.

Methods

Retrospective clinical and radiological evaluations were done on 17 patients with Crowe type III or IV developmental DDH treated by THA. There were 14 women and 3 men with a mean age of 52.3 years. Follow-ups averaged 52 months. Six cases were treated with two-stage THA followed by surgical hip liberalization and skeletal traction for 2 weeks.

Results

The mean Harris hip score improved from 40.9 to 89.1, and mean leg length discrepancy (LLD) in 13 unilateral cases was reduced from 2.95 to 0.8 cm. In the patients who underwent two-stage surgery, no nerve palsy was observed, and the single one-stage patient with incomplete peroneal nerve palsy recovered fully 4 weeks postoperatively.

Conclusions

The short-term clinical and radiographic outcomes of primary cementless THA for patients with Crowe type III or IV DDH were encouraging. Two-stage THA followed by skeletal traction after soft tissue release could provide alternative solutions to the minimization of limb shortenings or LLD without neurologic deficits in highly selected patients.     

Complete polyethylene wear-through and secondary breakage of the expansion cup in a ceramic-polyethylene total hip arthroplasty

Introduction

Catastrophic polyethylene failure is an uncommon complication of ceramic-on-polyethylene total hip arthroplasty (THA) because of the favourable tribological characteristics of these implants. We present a case of a 50-year-old woman who formerly underwent bilateral ceramic-on-polyethylene THA with expansion acetabular cups and eleven years later presented with unilateral THA dislocation, secondary to catastrophic polyethylene failure and metal shell fracture.

Case presentation

The patient came to our hospital for worsening pain in her left hip and an acute incapacity to bear weight on her left lower limb. Twelve and eleven years earlier she had undergone bilateral ceramic-on-polyethylene THA with acetabular expansion components of identical size on both sides. Radiographically, the left femoral head appeared superiorly dislocated and severe polyethylene wear was detected. The inclination angles of the left and right cups were 60° and 44°, respectively. The patient underwent left acetabular revision, and complete polyethylene wear-through with fracture of a cranial lobe of the expansion metal shell was noted at surgery. One large osteolytic lesion in the roof of the acetabulum and diffuse periarticular metallosis were also present. These findings required the use of a Burch–Schneider reinforcement cage. Two years later the patient is functioning well and has full autonomy in her activities of daily living.

Conclusion

The correct inclination of the acetabular component is necessary to prevent accelerated polyethylene wear in THA, even though favourable articular bearing surfaces have been used (e.g., ceramic-on-polyethylene coupling). Should the cup appear well fixed and fairly oriented on follow-up radiographies, the early detection of severe polyethylene wear may permit a revision of only the femoral head and acetabular liner.     

Effectiveness of an accelerometer-based portable navigation for intraoperative adjustment of leg length discrepancy in total hip arthroplasty in the supine position

BackgroundThis study aimed to examine the accuracy of the HipAlign® accelerometer-based portable navigation system by measuring the intraoperative leg length change of patients who underwent total hip arthroplasty (THA) and comparing the measured leg length discrepancy (LLD) determined by the navigation system and a freehand technique.MethodsA total of 61 patients who underwent THA using the anterolateral approach in the supine position were included in this study and divided into two groups: those who underwent THA with navigation (Group N; N = 31) and with the freehand technique (Group F; N = 30). Statistical analyses were performed to compare the intraoperative leg length change, pre- and post-LLD, absolute values of post-LLD, and the number of patients with the postoperative LLD within 10 mm and 5 mm between the two groups. Additionally, we examined the correlation between the leg length change obtained through intraoperative navigation and measured from the radiographs. Moreover, to evaluate the navigation accuracy, we examined the correlation between the absolute error of leg length change and cup orientation.ResultsThe postoperative LLD was significantly lower and the number of patients with the postoperative LLD within 5 mm was significantly higher in Group N, compared with Group F. Additionally, the amount of leg length change measured intraoperatively by the navigation system was strongly correlated with the values obtained by the postoperative radiographic measurement with a small absolute error and minimal wasted time. Moreover, a significant positive correlation was found between the absolute error of the leg length change and that of the cup inclination.ConclusionsOur study demonstrates that the accelerometer-based portable navigation system is useful for the intraoperative adjustment of leg length discrepancy during THA for patients in the supine position, as it provides good accuracy and minimizes required time for use.     

The value of computed tomography based navigation in revision total hip arthroplasty

Purpose

This study investigates the accuracy of a computed tomography (CT)-based navigation system for accurate acetabular component placement during revision total hip arthroplasty (THA).

Methods

We performed a retrospective review of 30 hips in 26 patients who underwent cementless revision THA using a CT-based navigation system; the control group consisted of 25 hips in 25 patients who underwent cementless primary THA using the same system. We analysed the deviation of anteversion and inclination angles among the pre-operative plan, intra-operative records from the navigation system and data from postoperative CT scans.

Results

There were no significant differences between groups (P < 0.05) in terms of mean deviation between pre-operative planning and postoperative measurements or between intraoperative records and postoperative measurements.

Conclusion

CT-based navigation in revision THA is a useful tool that enables the surgeon to implant the acetabular component at the precise angle determined in pre-operative planning.     

Evaluation of the accuracy of acetabular cup orientation using the accelerometer-based portable navigation system

BackgroundAccurate orientation of acetabular and femoral components is important during total hip arthroplasty (THA). In recent years, several navigation systems have been developed. However, these navigation systems for THA are unpopular worldwide because of their high cost. We assessed the orientation accuracy of cups inserted using a disposable accelerometer-based portable navigation system for THAs.MethodsThis was a prospective cohort study. We analyzed 63 hips with navigation prospectively and 30 hips without navigation retrospectively as historical control. The patients underwent THA via the mini anterolateral approach in the supine position using an accelerometer-based portable navigation system. We compared the preoperative target angles, intraoperative cup angles using navigation records, postoperative angles using postoperative CT data, measurement errors of cup angles, and clinical parameters such as sex, treated side, age at surgery, and body mass index (BMI).ResultsThe average absolute error (postoperative CT-navigation record) was 2.7 ± 2.1° (inclination) and 2.7 ± 1.8° (anteversion), and the absolute error (postoperative CT-preoperative target angle) was 2.6 ± 1.9° (inclination) and 2.7 ± 2.2° (anteversion). The absolute error between postoperative CT and target angle with navigation was significantly lower than the error without navigation (inclination; p = 0.025, anteversion; p = 0.005). Cup malalignment (absolute difference of inclination or anteversion between postoperative CT and preoperative target angle of over 5°) was significantly associated with BMI value (OR: 1.3, 95% CI: 1.1–1.7). The absolute measurement error of cup inclination and anteversion was significantly correlated with patients’ BMI (inclination error: correlation coefficient = 0.53, p < 0.001, anteversion error: correlation coefficient = 0.58, p < 0.001).ConclusionsThe clinical accuracy of accelerometer-based portable navigation is precise for the orientation of cup placement, although accurate cup placement was affected by high BMI. This is the first study to report the accuracy of accelerometer-based portable navigation for THA in the supine position.     

Effect of pelvic obliquity on the orientation of the acetabular component in total hip arthroplasty

In infrapelvic obliquity, coronal pelvic malrotation entails a change in the spatial location of the bony acetabulum. In the present study, 77 patients presented with infrapelvic obliquity with types 1 and 2 hip pathologies in which the pelvis is lower and higher, respectively, on the short-leg side. The 2 types were classified into 3 subtypes (A, B, and C) according to the severity of the pelvic obliquity (0°-3°, 3°-6°, and >6°). Angles of inclination of pelvic obliquity postoperatively, anteversions, and inclinations (abduction angle) for acetabular components were measured after total hip arthroplasty. Increased inclination (mean, 8.79°) was observed in type 1C, where the angle of inclination to pelvic obliquity postoperatively was minimally corrected. This increase may lead to cup instability. Rebalancing the pelvis in these cases with preoperative skeletal traction and/or sufficient release of hip contractures may be necessary. A correction of the mean inclination of the cup by 8.79° is required.     

侧卧位时头尾侧骨盆倾斜对全髋关节置换髋臼杯外展角的影响及校正

 目的 探讨侧卧位时骨盆向头尾侧倾斜的程度及其对髋关节置换术中髋臼假体外展角的影响及校正方法。方法 将50例62髋拟行全髋关节置换术的患者随机分为校正组及对照组,均采用侧卧位后外侧入路手术。对照组25例28髋以常规方法放置髋臼假体,校正组25例34髋进行水平仪及铅垂法校正后放置髋臼假体。术后测量两组患者髋臼杯外展角,并比较与术中预估的差异。结果 校正组在侧卧位未校正前骨盆整体倾斜-1.647°±4.512°,向头侧倾斜-(4.989°±2.778°),向尾侧倾斜2.587°±1.927°;头侧倾斜偏离大于尾侧,差异有统计学意义。校正组术后髋臼杯外展角为42.685°±3.355°,术中预估与术后测量偏差1.962°±1.515°;对照组术后髋臼杯外展角为44.534°±4.844°,术中预估与术后测量偏差4.244°±3.042°;校正组偏差小于对照组,差异有统计学意义。结论 侧卧位时头尾侧骨盆倾斜影响术者对髋臼外展角的判断,可能造成髋臼假体放置角度不准确。通过水平仪及铅垂法进行校正可提高判定髋臼假体外展角的准确性。     

Does Patients' Perception of Leg Length After Total Hip Arthroplasty Correlate With Anatomical Leg Length?

Background

This study assessed the correlation among the patients' perception of the leg length discrepancy (LLD) after total hip arthroplasty (THA) and the anatomical and functional leg length, pelvic and knee alignments, and foot height.

Does Standing Affect Acetabular Component Inclination and Version After THA?

Background  

Avoiding complications after hip arthroplasty with hard-on-hard bearings, especially metal-on-metal, correlates with the position of the acetabular component. Supine imaging with conventional radiography has traditionally been utilized to assess component inclination (abduction), as well as anteversion, after THA and surface replacement arthroplasty (SRA). However, most adverse events with hard bearings (excessive wear and squeaking) have occurred with loading. Standing imaging, therefore, should provide more appropriate measurements.     

Lumbar Spine Fusion and Symptoms of Leg Length Discrepancy After Hip Arthroplasty

BackgroundHip length discrepancy (HLD) is common after total hip arthroplasty (THA); however, the effect of spinal fusion on perceived leg length discrepancy (LLD) symptoms after THA has not been examined. This study tested the hypothesis that LLD symptoms are increased in patients who underwent lumbar spinal fusion and THA, compared with patients with THA only.MethodsThis retrospective cohort study included 67 patients who underwent lumbar spinal fusion and THA, along with 78 matched control patients who underwent THA only. Hip and spine measurements were taken on postoperative, standing anterior-posterior pelvic, lateral lumbar, and anterior-posterior lumbar spinal radiographs. Perceived LLD symptoms were assessed via telephone survey.ResultsBetween the spinal fusion and control groups, there was no significant difference in HLD (M = 7.10 mm, SE = 0.70 and M = 5.60 mm, SE = 0.49) (P = .403). The spinal fusion patients reported more frequently noticing a difference in the length of their legs than the control group (P = .046) and reported limping “all the time” compared with the control group (P = .001). Among all patients with an HLD ≤10 mm, those in the spinal fusion group reported limping at a higher frequency than patients in the control group (P = .008). Patients in the spinal fusion group were also more likely to report worsened back pain after THA (P = .011) than the control group.ConclusionFrequencies of a perceived LLD, limping, and worsened back pain after THA were increased in patients with THA and a spinal fusion compared with patients who had THA only, even in a population with HLD traditionally considered to be subclinical. The results indicate that in patients with prior spinal fusion, precautions should be taken to avoid even minor LLD in the setting of THA.     

Acetabular and Femoral Component Positioning Using Direct Anterior Approach Versus Posterior Approach in Total Hip Arthroplasty

PurposeDirect anterior approach (DAA) has recently become popular in total hip arthroplasty (THA). However, irrespective of the surgical approach used, component malposition is an important factor affecting function and complications after THA. This study aims to compare component positioning on the femoral and acetabular side between DAA and posterior approach (PA) to the hip joint. We hypothesized that the two approaches are similar in terms of component positioning.MethodsWe prospectively studied 50 patients, matched according to age, sex, and body mass index, undergoing THA, divided non-randomly into 2 groups. Group 1 comprised 25 patients (35 hips) undergoing THA using DAA and group 2 comprised 25 patients (25 hips) undergoing THA using PA. Ten patients from group 1 had simultaneous bilateral THA. Radiological parameters studied were acetabular inclination (AI), coronal femoral stem alignment (CFA), leg length difference (LLD), acetabular cup version (AV), and femoral stem version (FV).ResultsThere was no significant difference in AI, CFA, LLD, AV, and FV between the two groups. Excellent to good inter and intra-observer reliability expressed in terms of intraclass correlation coefficient (ICC) was noted for all the radiographic measurements.ConclusionBoth DAA and PA for THA achieve comparable radiological component positioning. DAA may not provide any advantage over PA in terms of positioning of the prosthesis.Level of EvidenceLevel II, non-randomized comparative study.     

Evaluation of transesophageal atrial pacing in the prone and lateral positions

OBJECTIVE: To develop recommendations for positioning the second-generation pacing esophageal stethoscope for transesophageal atrial pacing in patients positioned prone (P), right lateral decubitus (RLD), and left lateral decubitus (LLD). DESIGN: Prospective; patients assigned consecutively. SETTING: Tertiary and university hospitals. PARTICIPANTS: Thirty (10 in each position group) adult patients undergoing surgery. INTERVENTIONS: The optimal depths of insertions (DOI) where pacing current threshold was minimal (THmin) were determined first when supine, then after positioning. MEASUREMENTS AND MAIN RESULTS: Transesophageal atrial pacing was successful in all patients supine and after positioning. The optimal DOI varied from 2 cm less deep to 4 cm deeper in positioned patients compared with supine patients. Patients positioned P required equal or up to 8 mA greater current outputs to achieve transesophageal atrial pacing; LLD and RLD patients may require up to 8 mA greater or lesser current compared with supine patients. CONCLUSION: Transesophageal atrial pacing can be used safely and effectively in patients positioned P, RLD, and LLD. Recommendations are presented for positioning the pacing esophageal stethoscope. Emphasis is given to using the lowest DOIs and smallest currents to reduce the chance of transesophageal ventricular pacing.     

Does a Cemented Cage Improve Revision THA for Severe Acetabular Defects?

Background  

Evidence suggests a growing incidence of revision total hip arthroplasty (THA) including a subset with large acetabular defects. Revision THA for severe acetabular bone loss is associated with a relatively high rate of mechanical failure.