What are the risk factors for dislocation in primary total hip arthroplasty? A multicenter case-control study of 128 unstable and 438 stable hips

Incidence of heterotopic ossification following total hip arthroplasty by approach: a systematic review

BACKGROUND

Heterotopic ossification (HO) formation has been increasingly recognized as a complication of major orthopedic surgeries, particularly total hip arthroplasty (THA). Though, the overall incidence of HO following THA has been well-documented, it is often not reported by severity or by surgical approach.

QUESTIONS/PURPOSES

(1) What are the demographics of patients with HO? (2) What is the severity of HO following THA using the Brooker classification? (3) What is the incidence and class of HO following different THA approaches (anterior, posterior, posterolateral, anterolateral, superior, lateral, trans-gluteal)? (4) What are the number and training level of surgeons who performed each procedure?

METHODS

The PubMed, Embase, and Web of Science databases were queried, and PRISMA guidelines were followed. Qualitative and quantitative analyses were performed using Microsoft Excel.

RESULTS

We isolated 26 studies evaluating 6512 total hip arthroplasties (THA). The mean HO percentage overall was 28.8%, mostly Class I (54.2%) or Class II (29.6%). The highest percentage of HO was associated with the modified direct lateral (57.2%) and the traditional lateral (34.6%) approaches. The lowest HO percentages were identified following posterolateral (12.8%) and direct superior approaches (1%). Most studies reported a singular senior surgeon operating within the same approach for all patients.

CONCLUSIONS

The traditional lateral and modified direct lateral approaches to THA resulted in the highest percentage of HO postoperatively. However, most ossification cases were not clinically significant and did not strongly affect overall patient morbidity. Further studies are warranted to identify an association between severity of ossification and different arthroplasty approaches.

Sex-based differences in neck selectivity in total hip arthroplasty using a modular femoral neck system

BACKGROUND

Dislocation is a major complication of total hip arthroplasty (THA). The modular femoral neck system provides practical advantages by allowing adjustment of neck version and length in the presence of intraoperative instability. Anatomical studies have identified morphological differences in the hip joint between men and women. Despite sex-based differences in hip morphology, it remains unclear whether such differences affect neck selectivity in THA using a modular neck system and whether this approach achieves anatomical reconstruction, thereby reducing complications such as dislocation. This study aimed to investigate gender differences in neck selectivity in THA with the modular neck system and assess the clinical impact of the modular neck system.

METHODS

A total of 163 THAs using a modular neck system were included in this study. Data on the type of modular neck and intraoperative range of motion (ROM) were retrieved from patient records. Pre- and post-operative leg length differences (LLD) were examined as part of the radiographic assessment. Dislocation was investigated as a postoperative complication.

RESULTS

Neck selectivity did not significantly differ between men and women. The comparison of pre- and post-operative LLD revealed a tendency for varus necks to improve LLD more than version-controlled necks. Furthermore, no significant correlation was found between intraoperative ROM and neck selectivity, or postoperative dislocation and neck selectivity.

CONCLUSIONS

This study on THA with a modular neck system provided valuable insights into sex-based differences in neck selectivity and highlighted the potential benefits of the modular neck system in addressing LLD and preventing postoperative dislocation.

Closed reduction of dislocated hip prosthesis using a traction table

This article describes three cases in which a dislocated hip prosthesis was reduced by a new reduction technique - that we previously described - using traction table. The dissociation of a prosthesis is a rare but serious complication of closed reduction manoeuvre. The new reduction manoeuvre using a traction table may be a good option to avoid dissociation of the prosthesis during closed reduction for treatment of dislocation after total hip arthroplasty.

Total hip arthroplasty in patients with colostomy: impact on inpatient complications, hospital costs, and length of stay

INTRODUCTION

The presence of permanent end-colostomy is traditionally thought of as a risk factor for complications following orthopedic joint replacement; however, literature supporting this association is scarce. This study aims to discern how length of stay, cost of stay, and inpatient complications following total hip arthroplasty (THA) are impacted by presence of colostomy.

METHODS

Data from the National Inpatient Sample was analyzed by International Classification of Diseases, 10th Revision, Clinical Modification regarding THA in patients with and without end-colostomy. Unmatched and matched analyses comparing length of stay, cost of stay, and post-operative adverse outcomes between the two groups were conducted. In the unmatched analysis, 445 THA patients with colostomy were compared to 367,449 THA patients without colostomy. The colostomy patients were then matched for age, sex, race, diabetes, obesity, and the matched groups consisted of 445 patients with and 425 patients without colostomy, respectively.

RESULTS

Compared to the THA without colostomy group, the colostomy group was significantly older, had longer hospital stays, and greater cost of stay. When matched for age and comorbidities, length of hospital stay (p < 0.001) and cost of stay (p = 0.002) remained significantly higher. The colostomy group was at significantly increased risk for periprosthetic fracture, dislocation, and infection compared to all THA patients. When matched for age and common comorbidities, the colostomy group had significantly higher risk in only periprosthetic dislocation [p = 0.003, OR 11.8 (1.6-4.6, 95% CI)] and periprosthetic infection [p < 0.05, OR 2.7 (0.97-7.7 95% CI)].

CONCLUSION

Patients with colostomy are at risk of longer hospital courses and greater incurred costs following THA compared to patients without colostomy. They are additionally at significantly increased risk of periprosthetic dislocation and periprosthetic infection, warranting treatment as high-risk patients.

STUDY DESIGN

Retrospective cohort study.

The Association of Sacro-Femoro-Pubic Angle and Postoperative Dislocation Following Total Hip Arthroplasty

BACKGROUND

Spino-pelvic orientation may affect dislocation risk following total hip arthroplasty (THA). It can be measured on lateral lumbo-pelvic radiographs. The sacro-femoro-pubic (SFP) angle, measured on an antero-posterior (AP) pelvis radiograph, is a reliable proxy for pelvic tilt, a measurement of spino-pelvic orientation measured on a lateral lumbo-pelvic radiograph. The purpose of this study was to investigate the relationship between SFP angle and dislocation following THA.

METHODS

An Institutional Review Board-approved retrospective case-control study was conducted at a single academic center. We matched 71 dislocators (cases) to 71 nondislocators (controls) following THA performed by 1 of 10 surgeons between September 2001 and December 2010. Two authors (readers) independently calculated SFP angle from single preoperative AP pelvis radiographs. Readers were blinded to cases and controls. Conditional logistic regressions were used to identify factors differentiating cases and controls.

RESULTS

The data did not show a clinically relevant or statistically significant difference in SFP angles after adjusting for gender, American Society of Anesthesiologists classification, prosthetic head size, age at time of THA, measurement laterality, and surgeon.

CONCLUSION

We did not find an association between preoperative SFP angle and dislocation following THA in our cohort. Based on our data, SFP angle as measured on a single AP pelvis radiograph should not be used to assess dislocation risk prior to THA.

Risk Factors for Dislocation following Total Hip Arthroplasty in Developmental Dysplasia of the Hip: A Systematic Review and Meta-Analysis

PURPOSE

This systematic review and meta-analysis aimed to identify risk factors of dislocation after total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH).

METHODS

A systematic literature review was performed on 18th August 2022 using Medline, Embase, Scopus, Web of Science electronic databases, and a manual search. The study was conducted according to the PRISMA guidelines and registered with PROSPERO. Statistical analysis includes assessment of heterogeneity and data synthesis using RevMan 5.4.

RESULTS

Review of five studies including 2865 patients and 116 dislocated hips found that lower body mass index (BMI) (SMD = 0.22, p = 0.04, I2 = 0%), Crowe classification type IV versus I, II, and III (OR = 2.70, p = 0.004, I2 = 51%), higher cup inclination (SMD = 0.39 p = 0.0007, I2 = 0%), femoral head size < 28 mm (OR = 5.07, p = 0.003, I2 = 71%), lateral surgical approach (OR = 1.96, p = 0.02, I2 = 0%), and postoperative infection (OR = 6.26, p < 0.0001, I2 = 0%) were significant risk factors. However, age, gender, cup anteversion, femoral osteotomy, vertical (V-COR) centre of rotation, intraoperative fracture, preoperative and postoperative leg length discrepancy (LLD) and previous hip surgery were not found to be significant risk factors.

CONCLUSION

This study underscores importance of these risk factors in THA planning for DDH patients to reduce dislocation risk. Further research needed to understand mechanisms.

Survivorship of the dual-mobility construct in elective primary total hip replacement: a systematic review and meta-analysis including registry data

INTRODUCTION

Dislocation is a common complication associated with total hip replacement (THR). Dual-mobility constructs (DMC-THR) may be used in high-risk patients and have design features that may reduce the risk of dislocation. We aimed to report overall pooled estimates of all-cause construct survival for elective primary DMC-THR. Secondary outcomes included unadjusted dislocation rate, revision for instability, infection and fracture.

METHODS

MEDLINE, EMBASE, Web of Science, Cochrane Library and National Joint Registry reports were systematically searched (CRD42020189664). Studies reporting revision (all-cause) survival estimates and confidence intervals by brand and construct including DMC bearings were included. A meta-analysis was performed weighting series by the standard error.

RESULTS

Thirty-seven studies reporting 39 case series were identified; nine (10,494 DMC-THR) were included. Fourteen series (23,020 DMC-THR) from five national registries were included. Pooled case series data for all-cause construct survival was 99.7% (95% CI 99.5-100) at 5 years, 95.7% (95% CI 94.9-96.5) at 10 years, 96.1% (95% CI 91.8-100) at 15 years and 77% (95% CI 74.4-82.0) at 20 years. Pooled joint registry data showed an all-cause construct survivorship of 97.8% (95% CI 97.3-98.4) at 5 years and 96.3% (95% CI 95.6-96.9) at 10 years.

CONCLUSIONS

Survivorship of DMC-THR in primary THR is acceptable according to the national revision benchmark published by National Institute for Clinical Excellence (NICE).

Dislocation and survival rate of dual mobility cups in revision total hip arthroplasty in patients with high risk of instability

PURPOSE

Instability remains as an unsolved complication after revision total hip arthroplasty (rTHA). Dual mobility (DM) cups have decreased dislocation rate in rTHA; however, there are few clinical studies that evaluate the risk of dislocation after rTHA in patients with high risk of instability.

METHODS

Between 2007 and 2019, 95 consecutive rTHA using a DM cup, in 93 patients with instability risk factors were retrospectively reviewed. Instability risk factors were defined as follows: deficient abductor mechanism (22.1%), previous dislocation (68.4%), Paprosky 3 acetabular bone defect (21.1%), neuromuscular disease (4.2%), lumbar spine arthrodesis (6.3%), and more than one previous surgery (33.6%). Mean follow-up was 4.3 ± 2.4 years. Clinical and radiographic parameters were reported. DM cup survival was determined using a Kaplan-Meier analysis with re-revision for any cause as the end-point. Surgical complications and re-dislocation rate was recorded.

RESULTS

Seven DM cups were re-revised; three due to aseptic loosening, three due to peri-prosthetic joint infection (PJI), and one due to instability. At seven years follow-up, the survival rate of the DM cup using re-revision for any reason as the end-point was 82.4% (95% confidence interval, 66.4-98.4%). There were 12 (12.6%) complications: two (2.1%) dislocations, six (6.3%) PJI, four (4.2%) peri-prosthetic fractures.

CONCLUSION

Our findings suggest DM cups are effective reducing dislocation rate in rTHA in patients with a high risk of instability, without increasing early aseptic loosening and with a low rate of dislocation. Nevertheless, longer follow-up is needed to confirm implant stability and dislocation rates in the long term.

Modular dual mobility articulation in primary and revision hip arthroplasty: lights and shadows

PURPOSE

The use of dual mobility cups in total hip arthroplasty has gained popularity in light of the fact it enables to reduce dislocation through increased jumping distance (JD) and impingement-free arc of movement. Modular Dual Mobility Cup (modular DMC) systems have been recently introduced to enable the use of dual mobility cups with standard metal-backed shells. The objective of this study was twofold: calculate the JD for each modular DMC system and conduct a systematic literature review to report clinical outcomes and reasons for failure of this construct.

METHODS

The JD was calculated using the Sariali formula: JD = 2Rsin [(π/2 - Ψ - arcsin (offset/R))/2]. A qualitative systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search for English and French articles between January 2000 and July 2020 was run on PubMed, EMBASE, Google Scholar, and Scopus with the primary objective of finding articles about modular DMC systems.

RESULTS

We identified eight 8 different manufacturers of modular DMC systems and 327 publications on the subject. After screening for duplicates and eligibility, we identified 229 publications: 206 articles were excluded because they contained no reports on modular DMC systems, whereas other three were not included because they focused on biomechanical aspects. Among the 11 included articles, 2 were prospective case series, 9 were retrospective case series. True dislocation occurred in 25 cases (0.9%), and six of them were solved by closed reduction without necessity of revision, while all 5 intraprosthetic dislocations were operated.

CONCLUSIONS

Modular DMCs are a valid method to deal with complex THA instability, with good clinical and patient-reported outcomes, low complication rates, and low revision rates at early follow-up. We would advise cautious optimism on the role of modular DMC implants, as it seems safer to use ceramic instead of metallic heads whenever possible to avoid the increase cobalt and chromium trace ion serum levels.

Malseating of Modular Dual Mobility Liners: High Prevalence in Revision Total Hip Arthroplasty

BACKGROUND

Modular dual mobility (MDM) acetabular components have become increasingly more popular in total hip arthroplasty (THA). Uncertainty remains regarding liner malseating and its consequences after 5 to 10 years, especially in patients who undergo revision THA. The objective of this study was to analyze the prevalence of malseating and implant survivorship of patients who underwent revision THA using an MDM liner.

METHODS

We retrospectively identified patients who had a minimum 2-year follow-up and underwent revision THA using an MDM liner. Patient demographics, implant details, mortality, and all-cause revisions were recorded. Patients who had radiographic follow-up were assessed for malseating. Kaplan Meier survival was used to determine implant survivorship. We included 143 hips in 141 patients. Mean age was 70 years (35 - 93 years) and 86 patients (60.1%) were female.

RESULTS

Overall implant survival was 89.3% (95% Confidence Interval (CI) 0.843 - 0.946) at a mean follow-up of 6 years (range 2 to 10) years. There were eight patients excluded from malseating assessment. Upon radiological review, 15 liners (11.1%) were malseated. Survival for all-cause revision for patients with malseated liners was 80.0% (12/15, 95% CI 0.62 - 0.99, P= 0.15) versus 91.5% in patients who had non-malseated liners (110/120, 95% CI 0.86 - 0.96). There were no intraprosthetic dislocations and 3.5% of the patients were revised due to instability. No liners were revised due to malseating, and no patients who had malseated liners were revised due to instability.

CONCLUSIONS

Using MDM components in our cohort comprised of revision THA was associated with a high prevalence of malseating and an overall survival of 89.3% at a mean follow up of 6 years. Malseating does not appear to impact implant survival at a mean follow-up of 6 years.

Using mesh in capsule anatomical reconstruction to enhance the stability of high-dislocation-risk hip arthroplasty: a randomized controlled trial

BACKGROUND

Dislocation is a common complication after total hip arthroplasty (THA). This study aimed to compare the outcomes of mesh reconstruction versus conventional capsular repair in maintaining capsular integrity and preventing dislocation after THA.

METHODS

This was a prospective, randomized controlled study of consecutive patients. A total of 124 high-dislocation-risk THAs were identified and randomized into two groups, one using mesh reconstruction and the other using the conventional capsular repair method. Perioperative data and radiological data were collected. Patients were followed up regularly. The main indices were the capsular integrity assessed by magnetic resonance imaging (MRI) and hip dislocation rate. The secondary indices included the Harris hip score (HHS), complications, and satisfaction.

RESULTS

A total of 106 patients completed the follow-up and the average follow-up times were 19 ± 3.1 and 18 ± 3.3 months. The operation time of the mesh group was longer than that of the conventional group (P < 0.001). There were minor differences in acetabular anteversion and abduction angle, and the other data showed no differences. MRI results indicated that the success rate of capsular repair was higher in the mesh group (50 hips, 98%) than in the conventional group (37 hips, 67%) (P < 0.001), and the others failed the repair. Three dislocations occurred in the conventional group, while none occurred in the mesh group. The preoperative HHS (30 points) and postoperative HHS (82 points) of the mesh group were similar to those (35 points, 83 points) of the conventional group (P = 0.164, P = 0.328). Satisfaction had no difference (P = 0.532).

CONCLUSIONS

Compared to conventional repair, mesh reconstruction can effectively maintain capsular integrity and decrease dislocation risk after THA without increasing complications.

LEVEL OF EVIDENCE

Therapeutic study, Level IA.

Does the Dual Mobility Cup Reduce Dislocation After Primary Total Hip Arthroplasty in Elderly Patients at High Risk of Dislocation?

OBJECTIVE

The dual mobility cup (DMC) is designed to extend the longevity of the prosthesis by improving stability, enhancing the range of motion, and decreasing impingement without increasing wear. We hypothesized that DMC would reduce the risk of dislocation in elderly patients. This study aimed to investigate the clinical and radiographic outcomes of DMC-total hip arthroplasty (THA) in elderly patients at high risk of dislocation.

METHODS

From June 2016 to March 2020, 94 patients with a mean age of 77.7 years (97 hips) who underwent a posterolateral approach for DMC-THA in our department were followed up for at least one year. Preoperative and postoperative pelvic tilt angles (PTA) and DMC orientation were prospectively collected for all patients. Intraoperative and postoperative complications were recorded. A parametric test was used for normal distribution, and a non-parametric test was used for non-normal distribution.

RESULTS

Abduction and anteversion angles of the cup were 42.4 and 18.0° in the supine position immediately postoperative. The average PTA for patients in the supine and standing positions were 26.5 and 34.5°, respectively. When moving from the supine to the standing position, patients experienced a mean posterior pelvic tilt of 9°. No intraoperative acetabular-related complications were recorded. Postoperative complications included early infection in one patient (1.0%) and dislocation in one patient (1.0%).

CONCLUSION

Our study demonstrates that DMC-THA provides satisfactory short-term outcomes in elderly patients at a high risk of dislocation, regardless of the change in PTA resulting from postural transition.

Specificity of estimating femoral anteversion using linea aspera version for total hip arthroplasty: A three-dimensional computed tomography study

Femoral anteversion is an important parameter that can prevent complication following total hip arthroplasty (THA) caused by improper positioning of the implant. However, assessing femoral anteversion can be challenging in situation with significant defect of the femoral neck. In this study, linea aspera version was nominated as alternative parameter to femoral anteversion. So, the main objective of this study is to determine whether femoral anteversion correlates with linea aspera version. Cross-sectional study. Three-dimensional images of 100 femora were generated and their femoral anteversion and linea aspera version was measured. Correlation between the parameters was calculated. The mean linea aspera version was 7.27° ± 12.17° (mean ± standard deviation) while the mean femoral anteversion was 11.84° ± 10.06°. The linea aspera version was inversely correlated with the femoral anteversion with a correlation coefficient of -0.85. Linea aspera should be considered as an additional bony landmark to assess proper implant positioning in THA.

Lumbar spinal fusion does not increase early dislocation risk in primary total hip arthroplasty through the direct anterior approach

INTRODUCTION

Patients with total hip arthroplasty (THA) and a concomitant lumbar spinal fusion (LSF) might have an increased incidence of revision surgery and postoperative complications such as early THA dislocation. The direct anterior approach (DAA) has gained popularity in THA due to its soft tissue-preserving nature and the relatively low dislocation risk. The purpose of the present study was to examine whether LSF patients undergoing minimally invasive THA through the DAA might have an increased risk of prosthetic-related complications compared to matched-control patients without a LSF.

MATERIALS AND METHODS

Patients who underwent THA through the DAA in our institution from January 2014 to December 2018 were identified. A total of 30 primary THA also underwent LSF within 3 months from the initial operation. These patients were randomly matched (1:3) for sex, age, and body mass index with patients who underwent primary THA in our institution without a history of LSF (control group). Peri and postoperative complications, revisions, radiographic and clinical outcomes were assessed retrospectively.

RESULTS

LSF patients who underwent THA through the DAA did not have an increased risk of prosthetic-related complications compared to matched-control subjects without a LSF (6.6% versus 4.4%, P < 0.05). The functional and radiological outcomes were similar between groups.

CONCLUSION

LSF patients undergoing THA could benefit from the DAA similarly to patients without LSF and without increased rate of early THA dislocation. Although the complex interplay between the lumbar spine and hip in THA patients warrants further investigation, the outcomes of THA through the DAA in LSF patients appear promising.

LEVEL OF EVIDENCE

Retrospective case-control study, III.

Improvement of surgical time and functional results after do-it-yourself 3D-printed model preoperative planning in acetabular defects Paprosky IIA-IIIB

INTRODUCTION

The correct positioning of the implant in revision total hip arthroplasty (rTHA) is critical to obtaining substantial functional outcomes, and to avoiding complications. Current literature supports three-dimensional (3D)-printed models as potentially useful tools for preplanning, as well as the "do it yourself (DIY)" methodology to reduce both the time and costs of this procedure. However, no study has determined the efficacy of both methods combined in a cohort of patients with severe acetabular defects. In the lack of bibliography, we performed rTHA after preoperative planning by DIY-3D-printed models to evaluate its influence in: 1) the surgical time, 2) the functional scores, 3) the intra and postoperative complications, and 4) the reconstruction of the center of rotation (COR) of the hip.

HYPOTHESIS

Preoperative planning through 3D-DIY printed models will both improve the accuracy of the implant positioning, and the surgical time, leading the latter to improved functional scores and reduced complications.

MATERIALS & METHODS

A comparative study of 21 patients with Paprosky IIB to IIIB acetabular defects who underwent rTHA after 3D-printed model preoperative planning by the DIY method between 2016 and 2019 was conducted. A historical cohort of 24 patients served as the comparator. Surgical time, reconstruction of the COR, functional scores, and complications were analyzed.

RESULTS

The mean follow-up was 32.4 (range, 12 to 60) months. All the patients showed significant improvement of the Harris hip score (HHS) after the operation (3D group: 26.58±10.73; control group 22.47±15.43 (p=0.00)). In the 3D-printed model preoperative planning group the mean operation time and the intraoperative complications were significantly lower (156.15±43.03min vs 187.5±54.38min (p=0.045); and 19% vs 62.5% (p=0.003), respectively), and the HHS and patient satisfaction score (PSS) were significantly greater (83.74±8.49 vs 75.59±11.46 (p=0.019); and 8.17±0.88 vs 7.36±1.17 (p=0.023), respectively). No differences were found in the postoperative complications, nor in the restoration of the COR as determined from the acetabular index, verticalization or horizontalization, although the acetabular index was closer to the intended one in the 3D-printed model planning group (46.67°±7.63 vs 49.22±8.1 (p=0.284)).

CONCLUSION

Preoperative planning of severe acetabular defects through 3D-printed models shortens the surgical time, leading to a decrease in complications and thus to better functional outcomes and greater patient satisfaction. Moreover, the DIY philosophy could decrease both the time and costs of traditional 3D planning.

LEVEL OF EVIDENCE

III, retrospective case matched study.

Development of prediction models for complications after primary total hip and knee arthroplasty: a single-centre retrospective cohort study in the Netherlands

OBJECTIVE

The aim of this study was to develop prediction models for patients with total hip arthroplasty (THA) and total knee arthroplasty (TKA) to predict the risk for surgical complications based on personal factors, comorbidities and medication use.

DESIGN

Retrospective cohort study.

SETTING

Tertiary care in outpatient clinic of university medical centre.

PARTICIPANTS

3776 patients with a primary THA or TKA between 2004 and 2018.

PRIMARY AND SECONDARY OUTCOME MEASURES

Multivariable logistic regression models were developed for primary outcome surgical site infection (SSI), and secondary outcomes venous thromboembolism (VTE), postoperative bleeding (POB), luxation, delirium and nerve damage (NER).

RESULTS

For SSI, age, smoking status, body mass index, presence of immunological disorder, diabetes mellitus, liver disease and use of non-steroidal anti-inflammatory drugs were included. An area under the receiver operating characteristic curve (AUC) of 71.9% (95% CI=69.4% to 74.4%) was found. For this model, liver disease showed to be the strongest predictor with an OR of 10.7 (95% CI=2.4 to 46.6). The models for POB and NER showed AUCs of 73.0% (95% CI=70.7% to 75.4%) and 76.6% (95% CI=73.2% to 80.0%), respectively. For delirium an AUC of 85.9% (95% CI=83.8% to 87.9%) was found, and for the predictive algorithms for luxation and VTE we found least favourable results (AUC=58.4% (95% CI=55.0% to 61.8%) and AUC=66.3% (95% CI=62.7% to 69.9%)).

CONCLUSIONS

Discriminative ability was reasonable for SSI and predicted probabilities ranged from 0.01% to 51.0%. We expect this to enhance shared decision-making in considering THA or TKA since current counselling is predicated on population-based probability of risk, rather than using personalised prediction. We consider our models for SSI, delirium and NER appropriate for clinical use when taking underestimation and overestimation of predicted risk into account. For VTE and POB, caution concerning overestimation exceeding a predicted probability of 0.08 for VTE and 0.05 for POB should be taken into account. Furthermore, future studies should evaluate clinical impact and whether the models are feasible in an external population.

Current Evidence for Spinopelvic Characteristics Influencing Total Hip Arthroplasty Dislocation Risk

BACKGROUND

Decreased pelvic mobility and pelvic retroversion may result from spinal degeneration and lead to changes in the orientation of the acetabular implant after total hip arthroplasty (THA). While multiple patient and surgery-related factors contribute to THA dislocations, there is increasing evidence that sagittal spinopelvic dynamics are relevant for THA stability. The aim of this systematic review was to assess the relationship between previously described sagittal spinopelvic characteristics and implant dislocations after primary THA.

METHODS

A comprehensive literature search in the PubMed and Embase databases was conducted for studies reporting on spinopelvic morphology, alignment, pathology, or surgery and THA dislocations. Risk of bias was assessed using the MINORS criteria. Because of high heterogeneity in study methodology, a synthesis of best evidence was performed. Odds ratios (ORs), relative risks (RRs), and effect sizes (g) were calculated.

RESULTS

Fifteen studies (1,007,900 THAs) with quality scores of 15 to 23 out of 24 were included. Nine different spinopelvic alignment parameters (8 studies, g = 0.14 to 2.02), spinal pathology (2 studies, OR = 1.9 to 29.2), and previous spinal fusion surgery (8 studies, OR = 1.59 to 23.7, RR = 3.0) were found to be related to THA dislocation. Conflicting results were found for another sagittal pelvic morphology parameter, pelvic incidence.

CONCLUSIONS

Several sagittal spinopelvic patient characteristics were found to be related to THA dislocation, and the associated risks were greater than for other patient and surgery-related factors. Future research is needed to determine which of those characteristics and parameters should be taken into account in patients undergoing primary THA.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Utility of Lesser Trochanter Version to Estimate Femoral Anteversion in Total Hip Arthroplasty: A Three-Dimensional Computed Tomography Study

Objective: Femoral anteversion is an important parameter that can prevent complication following total hip arthroplasty (THA) caused by improper positioning of the implant. However, assessing the femoral anteversion can be challenging in situations with significant defect of the femoral neck. In this study, the lesser trochanter version was nominated as alternative parameter to femoral anteversion. So, the main objective of this study is to determine whether the femoral anteversion correlates with the lesser trochanter version. Design: Retrospective study. Methods: Three-dimensional images of 100 femora were generated and their femoral anteversion and lesser trochanter version was measured. Correlation between the parameters were calculated. Results: The mean lesser trochanter version was 38.54° ± 7.86° (mean ± SD), while the mean femoral anteversion was 11.84° ± 10.06°. The lesser trochanter version was inversely correlated with the femoral anteversion with a correlation coefficient of −0.72. Conclusions: The lesser trochanter should be considered as an additional bony landmark to assess proper implant positioning in THA.

Dislocation risk after robotic arm-assisted total hip arthroplasty: a comparison of anterior, lateral and posterolateral approaches

AIMS

Dislocation is a major cause of early failure after THA and is highly influenced by surgical approach and component positioning. Robotic-arm assisted arthroplasty has been developed in an attempt to improve component positioning and reduce postoperative complications.The purpose of this study was to compare the rate of dislocation after robotic total hip arthroplasty through 3 different surgical approaches.

MATERIALS AND METHODS

All patients who had undergone robotic arm-assisted THA at 3 centres between 2014 and 2019 were reviewed. After applying exclusion criteria, 1059 patients were included in the study. An anterior approach was used in 323 patients, a lateral approach in 394 and a posterior approach in 342 patients.Episodes of dislocation were recorded after 6 months follow-up. Stem anteversion, cup anteversion, cup inclination and combined anteversion were collected using the integrated navigation system.Cumulative incidence (CI), incidence rate (IR) and risk ratio (RR) were calculated with a confidence interval of 95%.

RESULTS

3 cases of dislocation (2 posterior approach, 1 anterior approach) were recorded, with a dislocation rate of 0.28% and an IR of 0.14%.The rate of placement of the cup in the Lewinnek safe zone was 82.2% for the posterior approach, 82.0% for the lateral approach and 95.4% for the anterior approach.The rate of placement in the combined version safe zone was 98.0% for the posterior approach, 73.0% for the lateral approach and 47.1% for the anterior approach.The incidence rate of dislocation was 0.30% for the anterior approach, 0.34% for the posterior approach and 0% for the lateral approach.

CONCLUSIONS

The robotic arm-assisted technique is associated with a low risk of dislocation. The combined version technique appears to be a reliable way to reduce the risk of dislocation through the posterolateral approach but does not appear to be essential when using the lateral and anterior approaches.

Long-term survival of the Lefèvre retentive cup: 12-year follow-up analysis of 466 consecutive cases

INTRODUCTION

The Lefèvre retentive cup is a salvage solution for total hip replacement at high risk of dislocation. Only a few studies have reported the medium or long-term survival; most often, only a small number of patients were included in these studies. This led us to conduct a retrospective analysis of a large population to determine: 1) the 10-year survival rate after primary or revision arthroplasty, 2) the complication rate.

HYPOTHESIS

The dislocation rate is<5% for revision arthroplasty and<2% for primary arthroplasty.

MATERIAL AND METHODS

This single-center retrospective study included 466 consecutive total hip replacements performed with the Lefèvre retentive cup with a 12-year theoretical minimum follow-up (1/1/1998 to 31/8/2006). There were 257 indications for primary arthroplasty and 209 for revision arthroplasty. The cohort had 316 women and the mean age at surgery was 72.9years (30.2-89.9). The mean follow-up was 10.2±5 years (0.1-19.3). A statistical analysis was done based on the Kaplan-Meier survival curves in two subsets of patients: primary and revision surgery.

RESULTS

At the final review, 264 patients had died because of reasons unrelated to the procedures (mean 7.8±4.7years after the procedure), 48 were lost to follow-up (mean 3.0±3.3years after the procedure), and 39 patients (8%) had undergone acetabular revision of which 12 were for infection (2.5%), 25 were for loosening (5.4%) (5 femoral loosening only) and 2 were for dislocation (0.4%). In all, there were 10/466 dislocations (2.1%) of which 5/257 (1.9%) were in the primary group and 5/209 (2.4%) were in the revision group: 2 had a cup exchange and 8 were reduced by closed procedures. The probability of survival free of mechanical complications at 10years was estimated at 94.8%±1.6% (95% CI: 91.6%-98.0%) for the primary group and 87.8%±2.7% (95% CI: 82.4%-93.2%) for the revision groups (p=0.0017). There were 39 re-operations in the overall cohort: 1/257 (0.4%) for dislocation, 7/257 (2.7%) for aseptic loosening and 3/257 (1.2%) for infection in the primary group, while in the revision group, 1/209 (0.5%) was for dislocation, 18/209 (8.6%) for aseptic loosening and 9/209 (4.3%) for infection.

CONCLUSION

The Lefèvre retentive cup has good long-term survival with a low mechanical complication rate, both in primary and revision surgery. To us, this implant appears to be a reliable salvage procedure for total hip replacement in patients at high risk for dislocation.

LEVEL OF EVIDENCE

IV; retrospective study without control group.

Cementless hydroxyapatite-coated stem with dual mobility and posterior approach in over-80 year-old patients with osteoarthritis: Rates of dislocation and periprosthetic fracture at a mean 8 years' follow-up

BACKGROUND

Straight cementless stems are common in primary total hip arthroplasty (THA) in the elderly, but controversial due to higher risk of loosening and periprosthetic fracture (PPF). Apart from registries, results for the Corail implant and dual mobility (DM) in over-80 years-old are not known, notably in case of systematic association to a DM cup. We therefore performed a retrospective analysis of Corail implants in patients aged≥80years at implantation for osteoarthritis of the hip, assessing 1) PPF rate and survival for cementless straight stems associated to DM cups, 2) complications, and dislocation in particular, and 3) clinical scores.

HYPOTHESIS

PPF and dislocation rates are low in THA with cementless straight stem associated to DM cup in patients aged≥80years.

PATIENTS METHODS

A retrospective study was conducted in our department for the period July 2007 to December 2012. Inclusion criteria were age≥80years, with primary THA for osteoarthritis. Exclusion criteria were revision procedure and femoral neck fracture. One hundred and twenty-eight consecutive THAs were included, in 120 patients, with a minimum 5years' follow-up. Clinical results were assessed on Harris Hip Score (HHS) and Oxford Hip Score (OHS). Data were collected for PPF or dislocation and other complications.

RESULTS

At a mean 8±1 years' follow-up (range, 5-10 years), 66 patients (55%, for 68 hips) were alive, 48 (40%, for 54 hips) had died, and 6 (5%, for 6 hips) were lost to follow-up. Median age at surgery was 83years (range, 80-93years). Mean OHS at last follow-up was 41±6 (range, 21-48) and HHS 83±14 (range, 23-100) with mean gain of 32 points (95% CI, [28-36]; p<0.001)). There were 2 cases (1.6%) of PPF, at 2 and 65months, and no dislocations or cases of aseptic loosening. There were 2 cases (1.6%) of intraoperative calcar fracture, treated by wire cerclage with immediate complete weight-bearing, without further complications. With death as a competing risk, cumulative 10-year incidence of femoral stem revision was 1.6% [95% CI: 0.4-6.5], and cumulative incidence of all-cause revision was 4.1% [95% CI: 1.7-9.7].

DISCUSSION

In an over-80 year-old population, primary THA with straight cementless stem and 2nd generation dual mobility cup was an effective option with low risk of PPF or dislocation after a minimum 5-year of follow-up.

LEVEL OF EVIDENCE

IV; retrospective study.

A high body mass index tilts the pelvis caudally in the lateral decubitus position for total hip arthroplasty

BACKGROUND

Accurate cup placement is essential for obtaining excellent outcomes in total hip arthroplasty (THA). We evaluated the pelvic lateral tilt of the patient (which affects the incline of the acetabular cup in THA) and investigated the factors affecting it.

METHODS

We reviewed the medical records of THA procedures performed at our hospital between October 2015 and January 2021 for which an anteroposterior pelvic radiograph was always taken preoperatively once the patient was placed in the lateral decubitus position. These radiographs were used to measure the lateral pelvic tilt in each case. We analysed whether patient factors (sex, body mass index [BMI], range of motion of abduction or adduction in both hips, surgical history of both hips, and lumbar Cobb angle) influenced the tilt.

RESULTS

We reviewed 363 cases (341 primary, 22 revision). The mean pelvic lateral tilt was 4.1°, and the operated hip was located on the caudal side compared to the unoperated hip. Statistical analyses revealed that the patient BMI and surgical history of the operated and unoperated hips significantly influenced tilt.

CONCLUSIONS

The pelvis in the lateral decubitus position leaned 4.1° to the caudal side, most commonly due to a high BMI. Surgeons should consider this when performing acetabular cup implantation in THA.

The Impact of Femoral Component Cementation on Fracture and Mortality Risk in Elective Total Hip Arthroplasty: Analysis from a National Medicare Sample

BACKGROUND

Complications following elective total hip arthroplasty (THA) are rare but potentially devastating. The impact of femoral component cementation on the risk of periprosthetic femoral fractures and early perioperative death has not been studied in a nationally representative population in the United States.

METHODS

Elective primary THAs performed with or without cement among elderly patients were identified from Medicare claims from 2017 to 2018. We performed separate nested case-control analyses matched 1:2 on age, sex, race/ethnicity, comorbidities, payment model, census division of facility, and exposure time and compared fixation mode between (1) groups with and without 90-day periprosthetic femoral fracture and (2) groups with and without 30-day mortality.

RESULTS

A total of 118,675 THAs were included. The 90-day periprosthetic femoral fracture rate was 2.0%, and the 30-day mortality rate was 0.18%. Cases were successfully matched. The risk of periprosthetic femoral fracture was significantly lower among female patients with cement fixation compared with matched controls with cementless fixation (OR = 0.83; 95% CI, 0.69 to 1.00; p = 0.05); this finding was not evident among male patients (p = 0.94). In contrast, the 30-day mortality risk was higher among male patients with cement fixation compared with matched controls with cementless fixation (OR = 2.09; 95% CI, 1.12 to 3.87; p = 0.02). The association between cement usage and mortality among female patients almost reached significance (OR = 1.74; 95% CI, 0.98 to 3.11; p = 0.06).

CONCLUSIONS

In elderly patients managed with THA, cemented stems were associated with lower rates of periprosthetic femoral fracture among female patients but not male patients. The association between cemented stems and higher rates of 30-day mortality was significant for male patients and almost reached significance for female patients, although the absolute rates of mortality were very low. For surgeons who can competently perform THA with cement, our data support the use of a cemented stem to avoid periprosthetic femoral fracture in elderly female patients.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Calculation of the 3-D femoral component's orientation in total hip arthroplasty using a trigonometric algorithm

Femoral component orientation plays a key role in implant stability and therefore the success rate of total hip arthroplasty. To date, this topic has been studied using various definitions and a variety of imaging modalities and protocols. The aim of this study is a proof of concept that a new algorithm can be used to describe the femoral component’s 3D orientation on the three orthogonal anatomical planes and relative to its mechanical axis using input from two orthogonal planes. CT scans of 18 patients with a total of 22 hip arthroplasties were collected. From these, orthogonal coronal and sagittal projections of the complete femur were acquired in the scanning position (MIPs) and relative to the femoral mechanical axis (corrected MIPs). On these images, the orientation of the neck of the femoral component in space and relative to the femoral axis, respectively, was measured by coronal inclination (CI_F), sagittal inclination (SI_F) and transverse version (TV_F). With the algorithm, TV_F was also calculated based on CI_F and SI_F. Differences between measured and calculated TV_F and intra- and inter-observer reliability were evaluated using intra-class correlation coefficients (ICC). The error of non-orthogonal imaging (85° angle between the sagittal and coronal reconstructions) was tested on a third series of MIPs. The ICC between the calculated TV_F and manually measured TV_F, in space and relative to the femoral axis, was 0.98 for both with median absolute differences of 1.3 and 1.5°. For non-orthogonal images this was 0.70 with a median absolute difference of 5°. ICCs for intra-observer and inter-observer reliability for the calculated TV_F values were 0.98 and 0.88, respectively. With this algorithm the transverse orientation of the neck of the femoral component can be assessed in space and relative to the mechanical femoral axis by combining its sagittal and coronal orientation. As long as the imaging visualizes two orthogonal planes, the orientation of an implant can be assessed in 3-D, regardless of the imaging modality.

Outcomes and survival of a modern dual mobility cup and uncemented collared stem in displaced femoral neck fractures at a minimum 5-year follow-up

INTRODUCTION

The choice of implant type for total hip replacement in the treatment of femoral neck fractures remains debated. Some authors advocate for the systematic use of cemented stems, while others do not use dual mobility first-line. We therefore conducted a retrospective study using a dual mobility cup (DMC) and an uncemented collared stem (UCS) in order to: (1) confirm the low dislocation rate in this indication, (2) assess other surgical complications, in particular periprosthetic fractures, (3) ensure that these benefits are maintained over time, at a minimum follow-up of 5 years and, (4) assess the rate of revision of the implants.

HYPOTHESIS

Our hypothesis was that the dual mobility dislocation rate for the treatment of femoral neck fractures was lower than for bipolar hemiarthroplasties or single mobility hip prostheses.

PATIENTS AND METHODS

A retrospective study of 244 femoral neck fractures (242 patients) treated with DMC and UCS was conducted, between 2013 and 2014. The mean age was 83±10 years (60-104). The occurrence of dislocation, periprosthetic fracture, infection of the surgical site, loosening, reoperation and revision were investigated. The HOOS Joint Replacement (JR) score was collected. The cumulative incidence with mortality was used as a competing risk.

RESULTS

The mean follow-up was 6 years±0.5 (5-7). At the last follow-up, 108 patients (50%) had died. Twenty-three patients (9.5%) were lost to follow-up. One case of symptomatic aseptic loosening of DMC was observed. The cumulative incidence of dislocations and periprosthetic fractures at 5 years were 2% (95% CI: 0.9-5.4) and 3% (95% CI: 1.2-6), respectively. The 5-year cumulative incidence of surgical site infections was 3.5% (95% CI: 1.8-7). The cumulative incidence of reoperations at 5 years was 7% (95% CI: 4.5-11). The causes of reoperation were periprosthetic fracture (n=6), infection (n=8), postoperative hematoma (n=2) and cup malposition (n=2). The cumulative incidence of a revision at 5 years was 2.7% (95% CI: 1.2-6). The cumulative incidence of a surgical complication from any cause at 5 years was 9% (95% CI: 6.7-14.8). The mean HOOS JR score was 79±5 (52-92).

DISCUSSION

The cumulative incidence of dislocation at 5 years is low and other surgical complications (including periprosthetic fractures) do not increase during this period for DMC associated with UCS, in femoral neck fractures. The use of this type of implant is reliable in the treatment of femoral neck fractures.

LEVEL OF EVIDENCE

IV; retrospective study without control group.

Sexual activity resumption after total hip arthroplasty: A satisfaction survey in 101 patients

BACKGROUND

We are not aware of studies conducted in France to assess information provided by surgeons about the impact of total hip arthroplasty (THA) on sexual activity or sexual activity resumption after THA. The objectives of this study in a cohort of patients seen after THA were to evaluate: (1) the time to sexual activity resumption, (2) whether sexual activity resumption was discussed with the surgeon and whether the patients wanted information on this point, and (3) the modalities and experience of sexual activity resumption according to demographic features.

HYPOTHESIS

Age and sex influence the timing and modalities of sexual activity resumption after THA.

METHODS

We conducted a single-centre prospective cohort study in consecutive patients who received follow-up for 6months after THA. Each patient completed an anonymised questionnaire on preoperative sexual activity, modalities of postoperative sexual activity resumption, information delivered by the surgeon, and expectations regarding the delivered information. The patients also specified their age and sex on the questionnaire.

RESULTS

Of 101 included patients, 49 were still sexually active before surgery. Of these 49 patients, 35 (71.4%) reported no difference in the frequency of sexual activity before and after THA. Only 4 (8.2%) patients did not resume sexual activity during follow-up. Older age was associated with a lower demand for information [odds ratio, 0.95; 95% confidence interval: 0.91-0.99 (p=0.01)]. Compared to the females, the males more often recovered similar sexual activity to that before surgery regarding frequency [18/20 vs. 17/29 (p=0.02)] and quality of sexual positions [15/20 vs. 9/29 (p=0.003)]. Males resumed sexual activity on average during the first 3weeks [10/20 (p=0.02)], compared to after 6weeks for most females [13/29 (p=0.03)]. Age was not associated with the time to sexual activity resumption [ρ=0.0868; 95% confidence interval: -0.205 to 0.365 (p=0.56)].

DISCUSSION

Among patients who were sexually active before surgery, 71.4% reported having resumed the same frequency of sexual activity 6months after surgery. The main difficulty in both males and females was fear of prosthetic hip dislocation, which was related in part to insufficient preoperative information. Males resumed sexual activity earlier than did females. In patients who were sexually active before surgery, age was not associated with the resumption of sexual activity after surgery.

LEVEL OF EVIDENCE

IV, prospective study with no control group.

Risk factors of dislocation after total hip arthroplasty in patients with developmental dysplasia of the hip

PURPOSE

Dislocation following total hip arthroplasty (THA) is a well-known complication. However, there is little data on its rate and predictors in patients with developmental dysplasia of the hip (DDH). The current study is aimed to determine the rate and specific risk factors of dislocation following THA in DDH patients.

METHODS

All the medico-surgical records of primary THAs from January 2014 to January 2019 were retrospectively reviewed. They were categorized into three main groups: primary OA, DDH, and others. Pre-operative and post-operative radiographs, past medical and surgical history, and surgical notes were reviewed in DDH cases.

RESULTS

In a total of 171 patients with DDH, 21 suffered from dislocation after THA (12%) which was significantly more frequent than those with primary OA. In univariate analysis, higher grade of dysplasia, smaller head size, intra-operative fracture, Wagner Cone stem, failure of offset restoration, and implanting the cup outside the Lewinnek's safe zone were identified as predictors of dislocation. In multiple regression analysis, however, only higher Crowe grade, intra-operative fracture, and post-operative acetabular offset less than 16 mm were independent predictors of dislocation.

CONCLUSION

Dysplastic hips can be more prone to post-THA dislocation than those with primary OA. Higher grades of dysplasia, failure of offset restoration, and intra-operative fracture can increase the rate of dislocation in this group of patients.

The role of the femoral component orientation on dislocations in THA: a systematic review

INTRODUCTION

Dislocation remains a major complication in total hip arthroplasty (THA), in which femoral component orientation is considered a key parameter. New imaging modalities and definitions on femoral component orientation have been introduced, describing orientation in different planes. This study aims to systematically review the relevance of the different orientation parameters on implant stability.

METHODS

A systematic review was performed according to the PRISMA guidelines to identify articles in the PubMed and EMBASE databases that study the relation between any femoral component orientation parameters and implant stability in primary THA.

RESULTS

After screening for inclusion and exclusion criteria and quality assessment, nine articles were included. Definitions to describe the femoral component orientation and methodologies to assess its relevance for implant stability differed greatly, with lack of consensus. Seven retrospective case-control studies reported on the relevance of the transversal plane orientation: Low femoral- or low combined femoral and acetabular anteversion was statistical significantly related with more posterior dislocations, and high femoral- or combined femoral and acetabular anteversion with anterior dislocations in two studies. There were insufficient data on sagittal and coronal component orientation in relation to implant stability.

CONCLUSION

Because of incomparable definitions, limited quality and heterogeneity in methodology of the included studies, there is only weak evidence that the degree of transverse component version is related with implant stability in primary THA. Recommendations about the optimal orientation of the femoral component in all three anatomical planes cannot be provided. Future studies should uniformly define the three-dimensional orientation of the femoral component and systematically describe implant stability.

Acetabular Component and Liner Selection for the Prevention of Dislocation After Primary Total Hip Arthroplasty

»

Primary total hip arthroplasty (THA) is a reproducible and efficacious procedure for patients with end-stage osteoarthritis; however, dislocation remains the most common cause of revision arthroplasty.

»

Technological advancements in acetabular component design and liner options, in conjunction with a more comprehensive understanding of the spinopelvic factors that influence dislocation, will likely reduce the risk of dislocation and revision over time.

»

The contemporary liner and shell options for primary THA, in order of increasing constraint and stability, include (1) neutral, (2) lateralized, (3) face-changing (oblique), (4) lipped (high-wall) with or without lateralization, (5) modular and anatomic dual-mobility, and (6) constrained options.

»

Different liner designs can alter functional anteversion, inclination, and jump distance, and can be used to minimize a single predictable dislocation vector (lipped [high-wall] liners) or multiple vectors of instability risk when the dislocation direction is unpredictable (dual-mobility liners).

»

Liner selection should be based on the patient-specific risk of dislocation, including static anatomic (e.g., large anterior inferior iliac spine or greater trochanter morphology), dynamic anatomic (e.g., limited sitting-standing change in the sacral slope), and demographic or medical (e.g., neurocognitive disorders and obesity) risk factors.

Minimally invasive anterolateral approach versus lateral transmuscular approach for total hip arthroplasty: A systematic review and meta-analysis

BACKGROUND

Total hip arthroplasty (THA) using a minimally invasive (MI) approach is a commonly performed procedure, and several approaches are now being used clinically. The MI anterolateral (MIAL) approach is one of the MI approaches used in clinical practice. Whether the MIAL approach is superior to non-MI approaches remains controversial. To resolve this controversy, we performed a systematic review and a meta-analysis of results of THA procedures that used the MIAL approach. We assessed whether the MIAL approach was superior to the lateral transmuscular (LT) approach in terms of operative time, operative blood loss, radiological parameters, and clinical outcomes.

METHODS

We performed a methodical search for all literature published on PubMed, Web of Science, and the Cochrane Library, and pooled data using the RevMan software. A p value < 0.05 was considered statistically significant. We calculated the mean differences (MD) for continuous data with 95% confidence intervals (CI) for each outcome.

RESULTS

This meta-analysis included 6 studies. Pooled results indicated no statistically significant differences between the groups in terms of operative time (MD = 5.13, 95% CI -2.49 to 12.75, p = 0.19), cup abduction angle (MD = 1.64, 95% CI -1.32 to 4.60, p = 0.28), and cup anteversion angle (MD = 0.75, 95% CI -1.09 to 2.59, p = 0.43). Operative blood loss was significantly greater in those who underwent THA via the MIAL approach than those who underwent THA via the LT approach (MD = 68.01, 95% CI 14.69 to 121.33, p = 0.01). The postoperative Harris hip score (HHS) assessed at the time of final follow-up was significantly higher in those who underwent THA via the MIAL approach than those who underwent THA via the LT approach (MD = 1.41, 95% CI 0.50 to 2.33, p = 0.002).

CONCLUSION

We conclude that the MIAL approach is superior to the LT approach in terms of clinical outcomes.

LEVEL OF EVIDENCE

Level Ⅱ.

The effect of cemented acetabular component geometry on the risk of revision for instability or loosening : a study of 224,874 primary hip arthroplasties from the National Joint Registry

AIMS

To determine if primary cemented acetabular component geometry (long posterior wall (LPW), hooded, or offset reorientating) influences the risk of revision total hip arthroplasty (THA) for instability or loosening.

METHODS

The National Joint Registry (NJR) dataset was analyzed for primary THAs performed between 2003 and 2017. A cohort of 224,874 cemented acetabular components were included. The effect of acetabular component geometry on the risk of revision for instability or for loosening was investigated using log-binomial regression adjusting for age, sex, American Society of Anesthesiologists grade, indication, side, institution type, operating surgeon grade, surgical approach, polyethylene crosslinking, and prosthetic head size. A competing risk survival analysis was performed with the competing risks being revision for other indications or death.

RESULTS

The distribution of acetabular component geometries was: LPW 81.2%; hooded 18.7%; and offset reorientating 0.1%. There were 3,313 (1.5%) revision THAs performed, of which 815 (0.4%) were for instability and 838 (0.4%) were for loosening. Compared to the LPW group, the adjusted subhazard ratio of revision for instability in the hooded group was 2.31 (p < 0.001) and 4.12 (p = 0.047) in the offset reorientating group. Likewise, the subhazard ratio of revision for loosening was 2.65 (p < 0.001) in the hooded group and 13.61 (p < 0.001) in the offset reorientating group. A time-varying subhazard ratio of revision for instability (hooded vs LPW) was found, being greatest within the first three months.

CONCLUSION

This registry-based study confirms a significantly higher risk of revision after cemented THA for instability and for loosening when a hooded or offset reorientating acetabular component is used, compared to a LPW component. Further research is required to clarify if certain patients benefit from the use of hooded or offset reorientating components, but we recommend caution when using such components in routine clinical practice. Cite this article: Bone Joint J 2021;103-B(11):1669-1677.

Femoral Head and Liner Exchange in Patients with Atraumatic Dislocation. Results of a Retrospective Study with 6 Years Follow-Up

Background and Objectives: Femoral head and liner exchange is an established treatment for polyethylene wear but has had a more limited role in the treatment of other conditions including dislocation, because of concerns about an increased postoperative dislocation rate. Some authors have considered dislocation associated with polyethylene wear to be a contraindication for this procedure. Materials and Methods: Our retrospective review evaluated the outcome of head and liner exchange in a small consecutively operated heterogeneous cohort of 20 patients who presented with dislocation unrelated to trauma, component malposition or component loosening. Of this group, 12 had prior primary total hip arthroplasty, and 8 had prior revision total hip arthroplasty, and included 4 patients with prior revision for dislocation. Mean follow-up was 6 ± 3.5 years (range 1–145 months). Results: Kaplan–Meier analysis revealed a revision-free implant survival from any cause of 80% (confidence interval 95%:64.3–99.6%) at 5 years after head and liner exchange (index surgery). At final follow-up, 83.3% of patients (n = 10) with prior primary total hip arthroplasty and 62.5% of patients (n = 5) with prior revision total hip arthroplasty, had not required subsequent revision for any cause. None (0%) of the primary total hip arthroplasty group and 3 (38%) of the revision arthroplasty group had required revision for further dislocation. Of the eight revision arthroplasty patients, four had a prior revision for dislocation and three of these four patients required further revision for dislocation after index surgery. The fourth patient had no dislocation after index surgery. One additional patient who had prior revision surgery for femoral component fracture suffered dislocation after index surgery, but was successfully treated with closed reduction. Conclusions: In our study population, femoral head and liner exchange was an effective treatment option for patients with prior primary total hip arthroplasty and also for a highly select group of revision total arthroplasty patients with no prior history of dislocation. Femoral head and liner exchange does not appear to be a viable treatment option for patients who have had revision total arthroplasty after prior dislocations.

Does obesity affect acetabular cup position, spinopelvic function and sagittal spinal alignment? A prospective investigation with standing and sitting assessment of primary hip arthroplasty patients

Background

Total hip arthroplasty (THA) instability is influenced by acetabular component positioning, spinopelvic function and sagittal spinal alignment. Obesity is considered as a risk factor of THA instability, but the causal relationship remains unknown. This study aimed to investigate the influence of BMI on (1) spinopelvic function (lumbar flexibility, pelvic mobility and hip motion), (2) sagittal spinal alignment pre- and postoperatively and (3) acetabular cup position postoperatively in primary THA patients in a prospective setting.

Methods

One hundred ninety patients receiving primary total hip arthroplasty were enrolled in a prospective cohort study and retrospectively analysed. All patients received stereoradiography (EOS) in standing and relaxed sitting position pre-and postoperatively. C7-sagittal vertical axis (C7-SVA), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), anterior plane pelvic tilt (APPT), and pelvic femoral angle (PFA) were assessed. Key parameters of the spinopelvic function were defined as lumbar flexibility (∆ LL = LL_standing − LL_sitting), pelvic mobility (∆ PT = PT_standing − PT_sitting) and hip motion (∆ PFA = PFA_standing − PFA_sitting). Pelvic mobility was further defined based on ∆ PT as stiff, normal and hypermobile (∆ PT < 10°; 10°–30°; > 30°). The patients were stratified to BMI according to WHO definition: normal BMI ≥ 18.5–24.9 kg/m² (n = 68), overweight ≥ 25.0–29.9 kg/m² (n = 81) and obese ≥ 30–39.9 kg/m² (n = 41). Post-hoc analysis according to Hochberg's GT2 was applied to determine differences between BMI groups.

Results

Standing cup inclination was significant higher in the obese group compared to the normal BMI group (45.3° vs. 40.1°; p = 0.015) whereas standing cup anteversion was significantly decreased (22.0° vs. 25.3°; p = 0.011). There were no significant differences for spinopelvic function key parameter lumbar flexibility (∆ LL), pelvic mobility (∆ PT) and hip motion (∆ PFA) in relation to BMI stratified groups. The obese group demonstrated significant enhanced pelvic retroversion compared to the normal BMI group (APPT − 1.8° vs. 2.4°; p = 0.028). The preoperative proportion of stiff pelvic mobility was decreased in the obese group (12.2%) compared to normal (25.0%) and overweight (27.2%) groups. Spinal sagittal alignment in C7-SVA and PI-LL mismatch demonstrated significantly greater imbalance in the obese group compared to the normal BMI group (68.6 mm vs. 42.6 mm, p = 0.002 and 7.7° vs. 1.2°, p = 0.032, respectively) The proportion of patients with imbalanced C7-SVA was higher in the obese (58.5%) than in the normal BMI group (44.1%).

Conclusions

The significantly increased spinal sagittal imbalance with altered pelvic mechanics is a potential cause for the reported increased risk of THA dislocations in obese patients. Consequently, the increased spinal sagittal imbalance in combination with normal pelvic mobility need to be taken into account when performing THA in obese patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02716-8.

The Use of Computer Navigation in Total Hip Arthroplasty Is Associated with a Reduced Rate of Revision for Dislocation: A Study of 6,912 Navigated THA Procedures from the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

The use of computer navigation has been shown to produce more accurate cup positioning when compared with non-navigated total hip arthroplasty (THA), but so far there is only limited evidence to show its effect on clinical outcomes. The present study analyzed data from the Australian Orthopaedic Association National Joint Replacement Registry to assess the impact of computer navigation on the rates of all-cause revision and revision for dislocation following THA.

METHODS

Data for all non-navigated and navigated primary THAs performed for osteoarthritis in Australia from January 1, 2009, to December 31, 2019, were examined to assess the rate of revision. We analyzed the effects of navigation on rate, reason, and type of revision. Hazard ratios (HRs) from Cox proportional hazard models, adjusted for age, sex, and head size, were utilized. Because of known prosthesis-specific differences in outcomes, we performed a further analysis of the 5 acetabular and femoral component combinations most commonly used with navigation.

RESULTS

Computer navigation was utilized in 6,912 primary THAs for osteoarthritis, with the use of navigation increasing from 1.9% in 2009 to 4.4% of all primary THAs performed in 2019. There was no difference in the rate of all-cause revision between navigated and non-navigated THAs looking at the entire group. There was a lower rate of revision for dislocation in the navigation THA cohort. The cumulative percent revision for dislocation at 10 years was 0.4% (95% confidence interval [CI], 0.2% to 0.6%) for navigated compared with 0.8% (95% CI, 0.8% to 0.9%) for non-navigated THAs (HR adjusted for age, sex, and head size, 0.46; 95% CI, 0.29 to 0.74; p = 0.002). In the 5 component combinations most commonly used with navigation, the rate of all-cause revision was significantly lower when these components were navigated compared with non-navigated. The cumulative percent revision at 10 years for these 5 prostheses combined was 2.4% (95% CI, 1.6% to 3.4%) for navigated compared with 4.2% (95% CI, 4.0% to 4.5%) for non-navigated THAs (HR, 0.64; 95% CI, 0.48 to 0.86; p = 0.003).

CONCLUSIONS

This study showed that the use of computer navigation was associated with a reduced rate of revision for dislocation following THA. Furthermore, in the component combinations most commonly used with navigation there was also a reduction in the rate of all-cause revision.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

A Comparison of Revision Rates for Dislocation and Aseptic Causes Between Dual Mobility and Large Femoral Head Bearings in Primary Total Hip Arthroplasty With Subanalysis by Acetabular Component Size: An Analysis of 106,163 Primary Total Hip Arthroplasties

BACKGROUND

Dual mobility (DM) and large femoral head bearings (≥36 mm) both decrease the risk of dislocation in total hip arthroplasty (THA). There is limited comparable data in primary THA. This study compared the revision rates for dislocation and aseptic causes between DM and large femoral heads and subanalyzed by acetabular component size.

METHODS

Data from the Australian Orthopedic Association National Joint Replacement Registry were analyzed for patients undergoing primary THA for osteoarthritis from January 2008 (the year of first recorded DM use) to December 2019. All DM and large femoral head bearings were identified. The primary outcome measure was the cumulative percent revision (CPR) for dislocation and for all aseptic causes. The results were adjusted by age, sex, and femoral fixation. A subanalysis was performed stratifying acetabular component diameter <58 m and ≥58 mm.

RESULTS

There were 4942 DM and 101,221 large femoral head bearings recorded. There was no difference in the CPR for dislocation (HR = 0.69 (95% CI 0.42, 1.13), P = .138) or aseptic causes (HR = 0.91 (95% CI 0.70, 1.18), P = .457). When stratified by acetabular component size, DM reduced the CPR for dislocation in acetabular component diameter <58 mm (HR = 0.55 (95% CI 0.30, 1.00), P = .049). There was no difference for diameter ≥58 mm. There was no difference in aseptic revision when stratified by acetabular component diameter.

CONCLUSION

There is no difference in revision rates for dislocation or aseptic causes between DM and large femoral heads in primary THA. When stratified by acetabular component size, DM reduces dislocation for acetabular component diameter <58 mm.

LEVEL OF EVIDENCE

Level III.

Can a simple iPad app improve C-arm based component position in anterior THA?

INTRODUCTION

Correct acetabular component positioning improves hip biomechanics, impingement free range of motion and may lead to a reduced risk of postoperative dislocation. The C-arm is a simple and cost-effective tool for THA in a supine position, however, evaluation of the images can be challenging due to parallax. The current study aimed to investigate whether a software app-based measurement technique can control acetabular component position and leg length in anterior THA.

MATERIALS AND METHODS

Ninety-three patients with end-stage osteoarthritis aged 65.2 ± 9.6 years (range 30-86 years) were included in this prospective study. All patients underwent direct anterior THA using a Hana orthopedic surgery table. C-arm imaging and an iPad software app were used to determine intraoperative acetabular anteversion, inclination and leg length discrepancy. The app provides a measuring tool that is applied to intraoperative c-arm images. The intraoperative measurements were compared to the measurements of standard postoperative AP-pelvis radiographs.

RESULTS

Intraoperative software app-based anteversion measurements averaged 20.5° (range 16.0° to 24.0°) compared to 20.9° (range 14.7° to 25.6°) postoperatively. Mean intraoperative inclination was 40.5° (range 35° to 48°) compared to postoperative 40.7° (range 35° to 49°). Mean intraoperative leg length discrepancy was 0.9 mm (range - 4-5 mm) compared to postoperative 0.6 mm (range - 5-6 mm). A strong Pearson's correlation was observed between the intraoperative and postoperative measurements for anteversion (r = .701; P < .0001), inclination (r = .816; P < .0001) and leg length discrepancy (r = .542; P < .0001).

CONCLUSIONS

The software app used in the current study allowed for a simple and accurate measurement of intraoperative cup position and leg length in direct anterior THA.

Total Hip Arthroplasty (THA) for Femoral Neck Fractures: Comparison between Standard and Dual Mobility Implants

The purpose of this retrospective study is to compare the short-term clinical and radiological results between standard and dual mobility THA for femoral neck fractures (FNF) in older patients. The hypothesis is that the dual mobility cup (DMC) has the same outcomes but a lower dislocation rate than the standard THA. The study population included 56 patients (mean age 77.7 years, range 71–85) that underwent THA for displaced FNF. Patients were divided in two comparable groups for baseline characteristics (age, sex and comorbidities): 28 patients underwent THA with a standard cup (SC) and 28 THA with DMCs. The clinical records and radiograms were reviewed to search relevant data in their postoperative history. Two postoperative dislocations occurred in the SC group and none in the DMC group. At an average follow up of 23 months (12–40), 48 patients were available for the final evaluation. The WOMAC score for all patients averaged 6.26 (0–46) and was slightly better in the DMC group (4.94 vs. 7.58; p-value = 0.41); scores were significantly better in presence of neurological comorbidities (p-value = 0.04), in the absence of diabetes (p-value = 0.04) and in the case of psychiatric disorders (p-value = 0.02). Radiographic evaluation at one year showed signs of osteointegration in 42/48 (87.5%) acetabular components (20 DMCs, 22 SC). According to our experience, DMCs proved to be a valid option for the treatment of displaced FNF in older patients, since it allowed them to achieve short-term outcomes comparable to conventional THA, while decreasing the incidence of postoperative dislocations.

Instability After Total Hip Arthroplasty and the Role of Advanced and Robotic Technology

Instability remains the leading cause of reoperation following total hip arthroplasty (THA). In this article, the risk factors for instability after THA are reviewed, including patient-related characteristics, surgical techniques, positioning of implants, and the role of advanced technology and robotics as a platform that may reduce the incidence of instability.

Pelvic Tilt and the Pubic Symphysis to Sacrococcygeal Junction Distance: Risk Factors for Hip Dislocation Observed on Anteroposterior Pelvis Radiographs

BACKGROUND

Dislocation after total hip arthroplasty (THA) is among the most common causes of early revision in contemporary practice. Abnormal spinopelvic alignment increases risk for dislocation, but methods to identify such are limited and can be complex. We sought to determine the effect of pelvic tilt, using a novel radiographic measurement, on dislocation risk by evaluating those with and without a history of dislocation.

METHODS

Using our institutional total joint registry, we identified 10,082 primary THAs performed between 2006 and 2015. Postoperatively, 177 dislocated (1.7%). Dislocators were matched 1:1 to control patients who did not dislocate. Pelvic tilt was calculated using the pubic symphysis to sacrococcygeal junction distance (PSCD) from a supine anteroposterior pelvis radiograph both preoperatively and postoperatively. The association between dislocation and both pelvic tilt and PSCD was then evaluated by logistic regression. Mean follow-up was 3 years.

RESULTS

Patients who dislocated had more posterior pelvic tilt (mean pelvic tilt of 57° vs 60°; P = .02) and smaller PSCDs (mean 41 mm vs 46 mm; P = .04) than controls. Patients with a PSCD <0 mm (symphysis above sacrococcygeal junction) had 9-fold odds of dislocation compared to those with a PSCD >50 (odds ratio 9; P = .006).

CONCLUSION

Patients who dislocated following primary THA had more posterior pelvic tilt. Additionally, those with a PSCD <0 had 9-fold odds of dislocation. Assessing the PSCD can alert a surgeon of increased risk for dislocation and identification of a negative PSCD should encourage further investigation or optimization of the preoperative plan to minimize dislocation risk.

LEVEL OF EVIDENCE

Level IV, case-control study.

Difference in tapered wedge stem alignment between supine and lateral position in cementless total hip arthroplasty via modified Watson-Jones anterolateral approach

BACKGROUND

Whether different body positions during surgery affect postoperative stem alignment in total hip arthroplasty (THA) remains unclear. The purpose of this study was to clarify differences in tapered wedge stem alignment between supine and lateral positions in THA under the modified Watson-Jones anterolateral approach.

METHODS

We reviewed 242 consecutive, primary cementless THAs performed with ceramic-on-cross-linked polyethylene via the modified Watson-Jones approach in either supine or lateral positions between 2009 and 2015 (supine group: 113 cases; lateral group: 129 cases). No specific reasons to select supine or lateral positions for the surgery were given during the study period. Computed tomography was performed pre- and postoperatively to measure preoperative femoral anteversion and postoperative stem anteversion, respectively. Stem alignment in coronal and sagittal planes was also evaluated.

RESULTS

Mean difference in stem anteversion and femoral anteversion was 8.6 ± 9.4 in the supine position and 13.0 ± 11.4 in the lateral position (p = 0.0013). Although no significant difference was seen between groups for stem alignment in the coronal plane, flexed implantation was more likely in the supine group (46/113, 40.7%) than in the lateral group (20/129, 15.5%). A significant correlation was found between femoral anteversion and stem anteversion in both the supine and lateral groups (r = 0.68, p < 0.0001 and r = 0.52, p < 0.0001, respectively).

CONCLUSION

Although stem anteversion was more strongly correlated with femoral anteversion in the supine position than in the lateral position, neutral position in the sagittal plane was more likely to be found with the lateral position than with the supine position. Surgeons can achieve ideal stem positioning by considering these results in the modified Watson-Jones approach in both the supine and lateral positions.

Use of a modular hip dual-mobility articulation in patients with high risk of dislocation: a relatively small-sized acetabulum in Asian patients may limit its use

BACKGROUND

Dual-mobility hip component is widely used in Europe and North America, because it effectively reduces hip dislocation in primary and revision total hip arthroplasties. However, reports were limited on the use of dual-mobility articulation in Asian populations.

PURPOSE

The aim of this retrospective study was to review the use of modular dual-mobility hip articulation in Asian patients with the high risk factor for hip dislocation. We also discussed the potential concern on the use of dual-mobility articulation in Asian patients.

METHODS

From Jan 2018 to June 2019, 17 patients were included in this study. The mean age of the patients was (73.8 ± 9.5) years (range: 57-88 years). The mean size of acetabular cup and modular DM liner were (49.5 ± 3.4) mm (range, 46-58 mm) and (40.7 ± 3.4) mm (range, 38-48 mm), respectively. The mean follow-up period was (15.8 ± 3.9) months (range, 11-24 months). The primary outcome was the rate of hip dislocation. The secondary outcomes included the Harris Hip Score. Differences were considered statistically significant at p < 0.05.

RESULTS

Hip dislocation, loosening, peri-prosthetic fractures, or intra-prosthetic dislocation was not found in the series. The mean preoperative and postoperative Harris Hip Scores were 42.2 ± 17.2 (range, 15-80) and 74.7 ± 13.5 (range, 52-97), respectively, giving a mean improvement of 32.5 ± 17.2 (range, 4-72). The improvement was statistically significant (p < 0.05).

CONCLUSIONS

In Asian patients with high risk of hip dislocation, the use of modular dual-mobility hip component produces promising outcomes without hip dislocation, but the relatively small-sized acetabulum may limit it widespread application in other populations worldwide.

TRIAL REGISTRATION

HKUCTR-2913 .

Is convention hip precaution necessary after total hip arthroplasty?

Background:

Dislocation is one of the most common causes of revision after total hip arthroplasty (THA). Standard hip precautions are thought to enhance soft-tissue healing and reduce dislocations. However, lifestyle restrictions affect a patient’s rehabilitation, quality of life (QOL), and satisfactions. We aim to compare conventional (CP) and minimal hip precautions (MP) after THA.

Methods:

Retrospective review of prospectively collected data in posterolateral approach THA. Chief surgeon assigns patients to CP or MP group. CP group had to sleep supine, used elevated toilet seats and chairs, avoid hip flexion greater than 90°, and no internal rotation or adduction for 6 weeks. MP group had no restrictions in hip movements, except for the combined flexion, adduction and internal rotation. All had a minimum 1-year follow-up. The number of dislocations, length of stay (LOS), time to independent toileting, Harris Hip Scores, QOL, and health perceptions, assessed by EuroQol 5D-5L, was compared between CP and MP groups.

Results:

Fifty-five THAs were included. CP group consisted of 17 primary and 12 revision THAs; MP group consisted of 21 primary and 5 revision THAs. There were two dislocations and both are revisions in CP group. Overall rate of dislocation was 6.9% in CP group and no dislocation in MP group (p-value > 0.05). MP group had shorter LOS (12 vs 19 days, p-value 0.04), higher EQ5D-5L health perception scores at 1-year (81.7 vs 70.9, p-value 0.01).

Conclusion:

MP group had shorter LOS and better health perceptions 1-year after THA with no increase in dislocation rates.

Cemented Dual Mobility Cup for Primary Total Hip Arthroplasty in Elder Patients with High-Risk Instability

Several studies have shown that double mobility (DM) cups reduce postoperative dislocations. Does the cemented dual mobility cup reduce dislocations in a specific cohort of elder patients with a high dislocation risk? Our hypothesis is that this implant is optimal for elder patients because it reduces early dislocation. We have retrospectively reviewed elder patients who underwent total hip arthroplasty (THA) with cemented double mobility cup between March 2009 and January 2018. The inclusion criteria were patients (>75 years) who were operated on for primary THA (osteoarthritis or necrosis) with a cemented dual mobility cup and a high-risk instability (at least two patient-dependent risk factors for instability). The exclusion criteria were revision surgeries or hip fracture. In all the cases, the same surgical approach was performed with a Watson Jones modified approach in supine position. We have collected demographic data, instability risk factors. Patients were classified using the Devane's score, Merle d'Aubigné score and the patient's likelihood of falling with the Morse Fall Scale. Surgical and follow-up complications were collected from their medical history. Sixty-eight arthroplasties (68 patients) were included in the study. The median age was 81.7 years (SD 6.4), and the American Society of Anesthesiologists (ASA) score showed a distribution: II 27.94%, III 63.24% and IV 8.82%. Devane's score was less than five in all of the cases. At least two patient-dependent risk factors for instability (87% had three or more) were present in each case. The median follow-up time was 49.04 months (SD 22.6). Complications observed were two cases of infection and one case of aseptic loosening at 15 months which required revision surgery. We did not observe any prosthetic dislocation. The cemented dual mobility cup is an excellent surgical option on primary total hip arthroplasties for elder patients with high-risk instability.

Salvage reconstruction of hip ligaments using absorbable material to treat recurrent instability of revision THA without abductor mechanism

Dual-mobility and constrained cups can stabilise most recurrent dislocations of total hip arthroplasty (THA), but may fail in case of hip abductor mechanism loss. For such complex situations, we developed an original artificial iliofemoral and ischiofemoral ligament reconstruction technique using a polyglactin 910 mesh (Vicryl ™) associated to repositioning of a Lefèvre constrained liner adapted to hip range of motion to prevent cam effects. The technique was implemented in 2 patients showing recurrent dislocation after THA, associating total femur replacement and cemented constrained liner in a metal reinforcement ring. In one of the 2 cases, the abductor mechanism had been entirely sacrificed. This simple and accessible salvage technique prevented recurrence of dislocation at 12 months' follow-up in these complex cases, previously subject to several episodes per year.

Is a portable accelerometer-based navigation system useful in total hip arthroplasty?: A systematic review and meta-analysis

BACKGROUND

Precise implant alignment is a crucial prognostic factor for successful outcomes following total hip arthroplasty (THA). A portable accelerometer-based navigation (PN) device may achieve the same accuracy as that achieved by the computer-assisted navigation surgery technique, with the convenience of a conventional technique. Although the usefulness of PN in THA (PN-THA) has been reported, whether it is more accurate than performing THA with a conventional technique (CON-THA) remains controversial. The difference in surgical time between PN-THA and CON-THA is also unclear. Therefore, we conducted a systematic review and meta-analysis of studies comparing results of PN-THA with those of CON-THA. We focused on the following question: is PN-THA superior to CON-THA in terms of radiological parameters and surgical time?

PATIENTS AND METHODS

A literature search was conducted in PubMed, Web of Science, and Cochrane Library, to identify studies that met the following inclusion criteria: randomised controlled trials (RCT) or non-RCT, studies involving patients who underwent PN-THA and patients who underwent CON-THA, studies including data on radiological parameters and surgical outcomes. Author names, publication year, country, study design, surgical approach, demographic characteristics of the participants (diagnosis, gender, age, and body mass index), and surgical outcomes (the radiological parameters and the surgical time) were extracted. We calculated the mean differences (MDs) for continuous data with 95% confidence intervals (CIs) for each outcome. p<0.05 was considered significant.

RESULTS

Three studies were included in this meta-analysis. The meta-analysis showed that absolute deviation of the postoperative measured angles from the target position for the cup anteversion was significantly smaller in PN-THA than in CON-THA (MD=-1.70, 95% CI=-2.91 to -0.50, [p=0.005]). There was no significant difference in the absolute deviation of the postoperative measured angles from the target position for cup abduction between the groups (MD=-1.82, 95% CI=-4.32-0.67, [p=0.15]). The surgical time was significantly longer in PN-THA than in CON-THA (MD=8.58, 95% CI=4.05-13.10, [p=0.0002]).

DISCUSSION

This systematic review and meta-analysis of studies comparing the results of PN-THA with those of CON-THA showed that the PN-THA is advantageous for precise cup implantation compared to CON-THA, although PN-THA has a longer surgical time compared to CON-THA.

LEVEL OF EVIDENCE

III.

Impact of Acetabular Implant Design on Aseptic Failure in Total Hip Arthroplasty

Background

Failure of cementless acetabular osseointegration is rare in total hip arthroplasty. Nevertheless, new fixation surfaces continue to be introduced. Novel implants may lack large diameter, constrained bearings, or dual mobility (DM) bearings to address instability. We compared clinical and radiographic outcomes for acetabular components with differing fixation surfaces and bearing options, focusing on the relationship between fixation surface and osseointegration and the relationship between bearing options and dislocation rate.

Methods

We retrospectively reviewed 463 total hip arthroplasties implanted with 3 different acetabular components between 2012 and 2016. Records were reviewed for demographics, clinical scores, and complications. Radiographs were examined for evidence of acetabular osteointegration. Analysis of variance and chi-square tests were used to compare cohorts.

Results

All cohorts had 100% survivorship free of acetabular fixation failure with no differences in clinical scores. Dislocation occurred in 1.3% of cases (n = 6). Analysis of the “transition” sizes, for which brand determined the maximum bearing diameter, revealed a significantly higher dislocation rate (3/50, 6%) in implants with limited bearing options. All 4 revisions for recurrent dislocation involved well-positioned components that did not accept large diameter, constrained bearings, or DM bearings, resulting in 3 shell revisions to expand bearing options. Femoral revisions were associated with dislocation risk but did not vary between cohorts.

Conclusion

Dislocation was the primary mechanical cause for acetabular revision, while acetabular fixation failure was not encountered. We caution against selecting “new and improved” acetabular components without options for large diameter, constrained bearings, or DM bearings, even when enabling technology makes component positioning reliable.

A Complication-Based Comparison Between the Posterior and Direct Lateral Approaches to Total Hip Arthroplasty: A Single-Center Experience

Introduction

Many approaches to performing total hip arthroplasty (THA) exist, primarily due to an insufficient amount of research that would favor one approach over the other. This study aimed to compare the risk of nerve injury, dislocation, Trendelenburg gait, and stem malposition between the direct lateral and posterior approaches to THA.

Methods

The study was a retrospective cohort study, and it was conducted in King Abdulaziz Medical City. It was directed toward adult patients who underwent THA from November 1, 2003, to November 1, 2018. All figures were obtained through the BESTCare system (ezCareTech, Saudi Arabia). Categorical variables were presented as frequencies and proportions. Quantitative variables were measured as mean and standard deviation. Fisher's exact test was used to compare the risk of complications between the two approaches.

Results

The posterior approach displayed a greater risk of stem malposition (p< 0.001) when compared with the direct lateral approach. However, neither approach showed a higher risk of dislocation, nerve injury, or Trendelenburg gait.

Conclusions

A higher risk of stem malposition was observed in the posterior approach, and there were no remarkable variances between the two approaches in the risk of dislocation, nerve injury, and Trendelenburg gait. Until more meticulous nationwide studies are available to provide evidence that would favor an approach over the other, the choice of surgical approach for THA remains to depend on the patient's characteristics and the surgeon's prior experience. Regardless of the approach, preoperative, intraoperative, and postoperative factors that increase the risk of complications should also be identified and addressed adequately.

Minimally invasive posterolateral hip approach with SPARTAQUUS (Spare the Piriformis And Respect The Active QUadratus femoris and gluteus mediUS) technique

Interest in the different surgical approaches to total hip arthroplasty remains high, but without any real consensus on which approach is the most beneficial. Several recent technical innovations have made it possible to reduce the risk of dislocation, therefore improving the efficacy of the posterolateral approach. Since 2003, we have been using a modified minimally invasive posterolateral approach called SPARTAQUUS (Spare the Piriformis And Respect The Active QUadratus femoris and gluteus mediUS), which spares the piriformis tendon, the quadratus femoris muscle and the gluteus medius muscle, and involves direct capsular repair. The "active posterosuperior hammock" effect of the piriformis tendon is therefore coupled with the "passive posterosuperior hammock" effect of the capsular repair, thus limiting the risks of posterior dislocation of the prosthetic hip joint.

Unstable total hip replacement: why? Clinical and radiological aspects

INTRODUCTION

Dislocation after total hip arthroplasty (THA) is the most common cause of revision hip surgery in the United States, ahead of aseptic loosening and infection, and is responsible for considerable economic cost related to frequent readmission and/or revision surgery. The aim of this article is to identify the clinical and radiological factors related to the unstable total hip replacement.

METHODS

We performed a literature search to assess current strategies to define clinical and radiological characteristics of dislocation after primary THA using the PubMed platform. The characteristics related to THA instability were divided into patient related factors, implant related factors and surgeon experience.

RESULTS

Patient-related factors for instability identified are: age; inflammatory joint disease; prior hip surgery; preoperative diagnosis; comorbidity; ASA score; presence of spino-pelvic abnormality; and neurological disability. Gender, simultaneous bilateral THA and restrictive postoperative precautions do not influence rate of THA dislocation. Implant related factors identified are: surgical approach; component malposition; femoral head size; and the use of dual-mobility or constrained solution. Surgeon experience also reduces the rate of dislocation.

DISCUSSION

Dislocation is a major complication of THAs, and causes include patient-derived factors, surgical factors, or both. It is imperative to determine the cause of the instability via a complete patient and radiographic evaluation and to adjust the reconstruction strategy accordingly.

Do All Rigid and Unbalanced Spines Present the Same Risk of Dislocation After Total Hip Arthroplasty? A Comparison Study Between Patients With Ankylosing Spondylitis and History of Spinal Fusion

BACKGROUND

Spines with ankylosis or with a history of lumbosacral fusions have been collectively classified as rigid and unbalanced, and associated with an increased rate of dislocation after total hip arthroplasty (THA). It remains unknown whether the cause of spinal arthrodesis influences the dislocation rate.

METHODS

A retrospective study was conducted from January 2000 to December 2017, with an institutional review board's approval to identify 2 cohorts with a history of THA: one with ankylosing spondylitis (AS) involving the lumbosacral spine and another cohort with a history of lumbosacral spinal fusion (SF). A chart review was performed to collect demographic and surgical variables. Lumbar lordosis angle (LLA), acetabular anteversion, and inclination angle measurements were taken for each patient. Kaplan-Meier survivorship curves were constructed and multivariable Cox regression was performed for analysis.

RESULTS

The AS and SF cohorts consisted of 142 and 135 patients, respectively. The SF group had a greater mean LLA (34.18°) than the AS group (21°). A total of 16 patients (11.85%) suffered from dislocation after primary elective THA in the SF group, whereas 4 patients (2.82%) in the AS group. After multivariable Cox regression analysis, increasing LLA and hips outside of the Lewinnek safe zone were found to be associated with a higher hazard of dislocation after THA.

CONCLUSION

We found that the degree of lumbar spine curvature is more associated with dislocation after THA than the history of SF itself; specifically, an increase in lumbar lordosis angle of 1º increases the probability of dislocation by 13% among AS and SF patients.