Total hip replacement for the treatment of end stage arthritis of the hip: a systematic review and meta-analysis

How-To Create an Orthopaedic Systematic Review: A Step-by-Step Guide. Part III: Executing a Meta-Analysis

At the top of the evidence-based pyramid, systematic reviews stand out as the most powerful, synthesizing findings from numerous primary studies. Specifically, a quantitative systematic review, known as a meta-analysis, combines results from various studies to address a specific research question. This review serves as a guide on how to: (1) design; (2) perform; and (3) publish an orthopedic arthroplasty systematic review. In Part III, we focus on how to design and perform a meta-analysis. We delineate the advantages and disadvantages of meta-analyses compared to systematic reviews, acknowledging their potential challenges due to time constraints and the complexities posed by study heterogeneity and data availability. Despite these obstacles, a well-executed meta-analysis contributes precision and heightened statistical power, standing at the apex of the evidence-based pyramid. The design of a meta-analysis closely mirrors that of a systematic review, but necessitates the inclusion of effect sizes, variability measures, sample sizes, outcome measures, and overall study characteristics. Effective data presentation involves the use of forest plots, along with analyses for heterogeneities and subgroups. Widely-used software tools are common in this domain, and there is a growing trend toward incorporating artificial intelligence software. Ultimately, the intention is for these papers to act as foundational resources for individuals interested in conducting systematic reviews and meta-analyses in the context of orthopaedic arthroplasty, where applicable.

Income and Insurance Status Impact Access to Health Care for Hip Osteoarthritis

Purpose

To explore differences in the affordability of and accessibility to health care among adults with hip osteoarthritis with respect to race/ethnicity, income, and insurance status.

Methods

This cross-sectional retrospective study was conducted using 2016 National Health Interview Survey (NHIS) data. NHIS data collection occurred continuously from January to December 2016. Individuals belonging to households and noninstitutionalized groups were included in the study. Because NHIS randomized surveys are conducted face-to-face on an annual basis, follow-up data are not collected.

Results

Answers from 38,158,634 weighted respondents with a mean age of 58.33 ± 0.33 years were assessed. Among adults with hip osteoarthritis, those with public insurance had increased odds of delaying care owing to lack of transportation and had decreased odds of delaying care and follow-up care owing to cost. Individuals who were uninsured or who belonged to lower income brackets were associated with increased odds of being unable to afford or utilize health care.

Conclusions

In this study, we found that income bracket and insurance status affect the accessibility to health care among adults with hip osteoarthritis in the United States.

Level of Evidence

Level IV, prognostic case series.

Assessing the predictive capacity of machine learning models using patient-specific variables in determining in-hospital outcomes after THA

Background

Machine learning is a subset of artificial intelligence using algorithmic modeling to progressively learn and create predictive models. Clinical application of machine learning can aid physicians through identification of risk factors and implications of predicted patient outcomes.

Aims

The aim of this study was to compare patient-specific and situation perioperative variables through optimized machine learning models to predict postoperative outcomes.

Methods

Data from 2016 to 2017 from the National Inpatient Sample was used to identify 177,442 discharges undergoing primary total hip arthroplasty, which were included in the training, testing, and validation of 10 machine learning models. 15 predictive variables consisting of 8 patient-specific and 7 situational specific variables were utilized to predict 3 outcome variables: length of stay, discharge, and mortality. The machine learning models were assessed in responsiveness via area under the curve and reliability.

Results

For all outcomes, Linear Support Vector Machine had the highest responsiveness among all models when using all variables. When utilizing patient-specific variables only, responsiveness of the top 3 models ranged between 0.639 and 0.717 for length of stay, 0.703-0.786 for discharge disposition, and 0.887-0.952 for mortality. The top 3 models utilizing situational variables only produced responsiveness of 0.552-0.589 for length of stay, 0.543-0.574 for discharge disposition, and 0.469-0.536 for mortality.

Conclusions

Linear Support Vector Machine was the most responsive machine learning model of the 10 algorithms trained, while decision list was most reliable. Responsiveness was observed to be consistently higher with patient-specific variables than situational variables, emphasizing the predictive capacity and value of patient-specific variables. The current practice in machine learning literature generally deploys a single model, it is suboptimal to develop optimized models for application into clinical practice. The limitation of other algorithms may prohibit potential more reliable and responsive models.Level of Evidence III.

Discharge Planning and Challenges for Patients With Asian Lifestyles Following Total Hip Arthroplasty: National Survey Design in Japan

This study examined discharge planning and challenges for patients following total hip arthroplasty in Japan. A cross-sectional national survey of 500 hospitals was conducted in May 2019. Discharge planning education tended to include content on dislocation prevention, including prevention while using a squat toilet and crouching down to sit on the floor or sleep on a futon on the floor-activities common in many Asian communities that require a maximum flexion of the hip joint. The challenges of discharge planning included diverse lifestyles, aging issues, lack of assistance at home, lack of consensus on dislocation prevention intervention, limitation of standardized care, interprofessional collaboration, and lack of time to educate family. Tailored discharge planning can be challenging, particularly for aged patients who practice "floor culture", i.e., sleeping, sitting and eating on the floor. Discharge planning needs to be task shifted from the surgeon to the nurse to enhance nurses' empowerment in Japan.

Statins, bone biology and revision arthroplasty: review of clinical and experimental evidence

Osteoarthritis is a painful, disabling condition which is increasing in prevalence as a result of an ageing population. With no recognized disease-limiting therapeutics, arthroplasty of the hip and knee is the most common and effective treatment for lower limb osteoarthritis, however lower limb arthroplasty has a finite life-span and a proportion of patients will require revision arthroplasty. With increasing life expectancy and an increasing proportion of younger (<65 years) patients undergoing arthroplasty, the demand for revision arthroplasty after implant failure is also set to increase.

Statins are cholesterol-modulating drugs widely used for cardiovascular risk reduction which have been noted to have pleiotropic effects including potentially influencing arthroplasty survival. In vitro studies have demonstrated pleiotropic effects in human bone cells, including enhancement of osteoblastogenesis following simvastatin exposure, and in vivo studies have demonstrated that intraperitoneal simvastatin can increase peri-implant bone growth in rats following titanium tibial implant insertion. There is evidence that statins may also influence osseointegration, enhancing bone growth at the bone–implant interface, subsequently improving the functional survival of implants. Data from the Danish Hip Arthroplasty Registry and the Clinical Practice Research Datalink in the UK suggest a reduction in the risk of lower limb revision arthroplasty in statin ever-users versus never-users, and a time-dependent effect of statins in reducing the risk of revision. In this article we review the clinical and experimental evidence linking statins and risk of revision arthroplasty.

Neck-sparing short femoral stems: A meta-analysis

BACKGROUND

Neck sparing short femoral stems are supposed to ease restoration of the proximal femoral anatomy and physiological hip biomechanics. This stem design is of particular interest as they have the potential to generate prosthetic hips that have higher functional performance with an improved lifespan, and revise more easily. Unlike previously published meta-analysis, this meta-analysis was initiated to determine if neck sparing short femoral stems compared to conventional stems: (1) resulted in improved functional performance; (2) reduced risk of thigh pain; (3) reduced risk of reoperation/revision, and 4) reduced stress shielding related bone loss in the proximal femur.

MATERIAL AND METHODS

Literature databases were searched between 1st January 2005 and 30th March 2019. The primary search was conducted using the electronic databases MEDLINE, EMBASE, PubMed, Open Grey, Trip Pro, Evidence Search, and Cochrane. Eligible studies were assessed for homogeneity, with continuous outcomes expressed as standardized mean difference with 95% confidence interval and dichotomous data as odds-ratio with 95% confidence interval.

RESULTS

Ten randomised clinical trials were eligible; these trials included 1259 total hip arthroplasty procedures, inclusive of 616 neck sparing short stems and 643 conventional stems. We were not able to find a significant functional advantage of using neck sparing short stems based on Harris Hip scores (0.0850; 95% CI: -0.03 to 0.20 [p=0.40]) and WOMAC scores (-0.0605; 95% CI: -0.03 to 0.15 [p=0.87]). We found a trend in favour of neck sparing short stems to reduce the risk of thigh pain but this was non significant (odds ratio of 0.11; 95% CI: 0.03 to 0.43 [p=0.178]). Neck sparing short stems were associated with similar early- to mid-term dislocation and revision rates compared to conventional stems with odds ratio of 1.435 (95% CI: 0.545 to 3.780 [p=0.968]) and of 0.581 (95% CI: 0.220 to 1.532 [p=0.972]), respectively. Neck sparing short stems were found to have less bone loss in both Gruen zones 1 and 7 (3.324; 95% CI: -7.683 to 1.036 [p<0.001], and of -4.632; 95% CI: -9682 to 0.418 [p<0.001], respectively).

DISCUSSION/CONCLUSION

Neck sparing short femoral stems achieve excellent early to mid-term outcomes in both clinical and radiological outcome scores that are in keeping with conventional stems functionally. Hitherto, results from this meta-analysis suggest that neck-sparing stems may achieve better maintenance of bone mineral density than their conventional counterparts, in addition to fewer cases of thigh pain.

LEVEL OF EVIDENCE

I; meta-analysis.

Simulated Performance of a Xenohybrid Bone Graft (SmartBone®) in the Treatment of Acetabular Prosthetic Reconstruction

Total hip arthroplasty (THA) is a surgical procedure for the replacement of hip joints with artificial prostheses. Several approaches are currently employed in the treatment of this kind of defect. Overall, the most common method involves using a quite invasive metallic support (a Burch-Schneider ring). Moreover, valid alternatives and less invasive techniques still need to be supported by novel material development. In this work, we evaluated the performance of SmartBone®, a xenohybrid bone graft composed of a bovine bone matrix reinforced with biodegradable polymers and collagen, as an effective support in acetabular prosthesis reconstruction. Specifically, the material's mechanical properties were experimentally determined (E = ~1.25 GPa, Ef = ~0.34 GPa, and Et = ~0.49 GPa) and used for simulation of the hip joint system with a SmartBone® insert. Moreover, a comparison with a similar case treated with a Burch-Schneider ring was also conducted. It was found that it is possible to perform THA revision surgeries without the insertion of an invasive metal support and it can be nicely combined with SmartBone®'s osteointegration characteristics. The material can withstand the loads independently (σmax = ~12 MPa) or be supported by a thinner titanium plate in contact with the bone in the worst cases. This way, improved bone regeneration can be achieved.

Effectiveness and Tolerability of Repeated Courses of Viscosupplementation in Symptomatic Hip Osteoarthritis: A Retrospective Observational Cohort Study of High Molecular Weight vs. Medium Molecular Weight Hyaluronic Acid vs. No Viscosupplementation

Background: Nonsurgical management of symptomatic hip osteoarthritis needs real-world evidence. We evaluated the effectiveness and tolerability of US-guided intra-articular treatment of two hyaluronic acids (HAs) commercially available in Italy and investigated predictors of response.

Methods: Outpatient records including three cohorts: 122 subjects treated with medium (1,500–3,200 kDa; Hyalubrix^®) molecular weight (MW) or high (hylan G-F20; Synvisc^®) MW HAs and 20 controls taking NSAIDs/analgesics on demand were retrospectively analyzed. Pain VAS score, WOMAC, NSAID/analgesic consumption, and causes of suspension were available at 1, 6, 12, and 24 months after first administration. As selection bias usually affects observational retrospective studies, a quasi-randomization process was attained by performing propensity score approach.

Results: Propensity score adjustment successfully allowed comparisons among balanced groups of treatments. VAS and WOMAC considerably decreased over time in treated groups independently of the radiological grade (p<0.001). On the other hand, the control group showed only a slight and rather uneven variation in VAS. Mean score changes were comparable in both HA cohorts from the earliest stages (ΔVAS(HA1,500–3,200kDa)_T1vsT0 = −20%; ΔVAS(hylan G-F20)_T1vsT0 = −23%/ΔWOMAC(HA1,500–3,200kDa)_T1vsT0 = −17%; ΔWOMAC(hylan G-F20)_T1vsT0 = −19%), reaching a further substantial reduction after 12 months (ΔVAS(HA1,500–3,200kDa)_T12vsT0 = −52%; ΔVAS(hylan G-F20)_T12vsT0 = −53%/ΔWOMAC(HA1,500–3,200kDa)_T12vsT0 = −45%; and ΔWOMAC(hylan G-F20)_T12vsT0 = −47%). Almost 11% (=13/122) of ineffectiveness and few moderate local side effects 3% (=4/122) were detected.

Conclusions: Viscosupplementation in a real-life setting seems to provide a sound alternative in pain management in comparison to oral NSAIDs/analgesics, guaranteeing a reduced intake of pain killer medications. Analgesic effectiveness, functional recovery, and reduced joint stiffness extend and improve over 12 and 24 months, suggesting that repeated administrations achieve an additive effect.

Disease-modifying drugs in osteoarthritis: current understanding and future therapeutics

INTRODUCTION

Osteoarthritis (OA) is a leading cause of pain and disability among adults with a current prevalence of around 15% and a predicted prevalence of 35% in 2030 for symptomatic OA. It is increasingly recognized as a heterogeneous multi-faceted joint disease with multi-tissue involvement of varying severity. Current therapeutic regimens for OA are only partially effective and often have significant associated toxicities. There are no disease-modifying drugs approved by the regulatory bodies. Areas covered: We reviewed the opportunities within key OA pathogenetic mechanism: cartilage catabolism/anabolism, pathological remodeling of subchondral bone and synovial inflammation to identify targeted disease-modifying osteoarthritis drugs, based on compounds currently in Phase II and III stages of clinical development in which x-ray and/or MRI was used as the structural outcome with/without symptomatic outcomes according to regulatory requirements. Expert opinion: Given the heterogeneity of the OA disease process and complex overlapping among these phenotypes, a 'one size fits all' approach used in most clinical trials would unlikely be practical and equally effective in all patients, as well as in all anatomical OA sites. On the other hand, it is a challenge to develop a targeted drug with high activity, specificity, potency, and bioavailability in the absence of toxicity for long-term use in this chronic disease of predominantly older adults. Further research and insight into evaluation methods for drug-targeted identification of early OA and specific characterization of phenotypes, improvement of methodological designs, and development/refinement of sensitive imaging and biomarkers will help pave the way to the successful discovery of disease-modifying drugs and the optimal administration strategies in clinical practice.

Introduction of New Technologies in Orthopaedic Surgery

The introduction of new devices, biologics, and combination products to the orthopaedic marketplace is increasing rapidly. The majority of these new technologies obtain clearance to market by demonstrating substantial equivalence to a predicate (previously approved device) according to the U.S. Food and Drug Administration (FDA) 510(k) process. Surgeons play a critical role in the introduction of new technologies to patients and must take a leadership role in promoting safe, efficacious, appropriate, and cost-effective care, especially for operative procedures. Surgeons should monitor and document their patients' clinical outcomes and adverse events when using new technology, to ensure that the new technology is performing as desired.

Nano-sized Al2O3 particle-induced autophagy reduces osteolysis in aseptic loosening of total hip arthroplasty by negative feedback regulation of RANKL expression in fibroblasts

Aseptic loosening is mainly caused by wear debris generated by friction that can increase the expression of receptor activation of nuclear factor (NF)-κB (RANKL). RANKL has been shown to support the differentiation and maturation of osteoclasts. Although autophagy is a key metabolic pathway for maintaining the metabolic homeostasis of cells, no study has determined whether autophagy induced by Al₂O₃ particles is involved in the pathogenesis of aseptic loosening. The aim of this study was to evaluate RANKL levels in patients experiencing aseptic loosening after total hip arthroplasty (THA) and hip osteoarthritis (hOA) and to consequently clarify the relationship between RANKL and LC3II expression. We determined the levels of RANKL and autophagy in fibroblasts treated with Al₂O₃ particles in vitro while using shBECN-1 interference lentivirus vectors to block the autophagy pathway and BECN-1 overexpression lentivirus vectors to promote autophagy. We established a novel rat model of femoral head replacement and analyzed the effects of Al₂O₃ particles on autophagy levels and RANKL expression in synovial tissues in vivo. The RANKL levels in the revision total hip arthroplasty (rTHA) group were higher than those in the hOA group. In patients with rTHA with a ceramic interface, LC3II expression was high, whereas RANKL expression was low. The in vitro results showed that Al₂O₃ particles promoted fibroblast autophagy in a time- and dose-dependent manner and that RANKL expression was negatively correlated with autophagy. The in vivo results further confirmed these findings. Al₂O₃ particles induced fibroblast autophagy, which reduced RANKL expression. Decreasing the autophagy level promoted osteolysis and aseptic prosthetic loosening, whereas increasing the autophagy level reversed this trend.

Cross-Linked Polyethylene for Total Hip Arthroplasty Markedly Reduces Revision Surgery at 16 Years

BACKGROUND

Total hip arthroplasty (THA) is an effective operation for the management of end-stage hip osteoarthritis, but long-term success can be limited by wear of the polyethylene bearing surface. Cross-linking conventional polyethylene has resulted in lower wear rates and a reduction in bone lysis in both laboratory and clinical studies. The aim of this study was to compare the rates of revision between cross-linked polyethylene (XLPE) and conventional non-cross-linked polyethylene (CPE) at 16 years after THAs performed for the treatment of osteoarthritis.

METHODS

We performed an observational study of data, from a national registry, on all patients who underwent THA for osteoarthritis in Australia from 1999 through December 31, 2016. The outcomes of THAs performed with CPE were compared with those of THAs performed with XLPE, along with an analysis of the effect of age, sex, femoral head size, the method of acetabular and femoral component fixation, and the reasons and types of revision. The principal outcome measure was the time to the first revision, determined using Kaplan-Meier estimates of survivorship.

RESULTS

CPE was used in 41,171 procedures, and XLPE was used in 199,131. The mean ages of the men and women treated with CPE were 70.0 years (standard deviation [SD] = 9.9 years) and 72.5 years (SD = 9.7 years), respectively, whereas the men and women who received XLPE were slightly younger (mean age, 68.6 years [SD = 10.3 years] and 70.7 years [SD = 9.9 years], respectively. XLPE was associated with a lower rate of revision than CPE at 6 months, and this difference became more apparent with time. The 16-year cumulative percentage of revisions of the primary THAs was 11.7% (95% confidence interval [CI] = 11.1% to 12.3%]) in the CPE group and 6.2% (95% CI = 5.7% to 6.7%) in the XLPE group. The hazard ratio at 9 years was 3.02 (p = 0.001).

CONCLUSIONS

The use of XLPE has resulted in a significant reduction in the rate of revision at 16 years following THA for osteoarthritis. This evidence suggests that the longevity of THA is likely to be improved, which may enable younger patients to undergo surgery, confident of a reduced need for revision in the long term.

LEVEL OF EVIDENCE

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

Load transfer and periprosthetic fractures after total hip arthoplasty: Comparison of periprosthetic fractures of femora implanted with cementless distal-load or proximal-load femoral components and measurement of the femoral strain at the time of implantation

BACKGROUND

Little is known about the causes and mechanisms underlying periprosthetic fractures around femoral components particularly in relation to the stem design. In an in vitro study 20 pairs of fresh cadaveric femora were loaded to fracture axially and transversally.

FINDINGS

When proximal femoral strain was measured at the time of impaction of cementless stems the load transfer was determined by the underlying anatomy rather than by the shape of the stem, so that the so-called "load transfer" properties - proximal or distal - ascribed to stem designs are a myth. The axial-load and the transverse-load model were then exposed to loads to failure (fracture) and showed a biphasic pattern throughout independent of the impact direction. In the second phase, the fracture phase proper, the bone behaved like a brittle solid. Failure occurred very rapidly within less than 5 milliseconds. The forces to failure were between 2 and 11 kN. Most of the fractures (82.5%) occurred above the stem tip.

INTERPRETATION

Note that the study was confined to early preosteointegration fractures. Neither the stem design nor the impact direction, i.e. on the knee or on the side of the hip, was related to the fracture morphology.

Surgical Space Suits Increase Particle and Microbiological Emission Rates in a Simulated Surgical Environment

BACKGROUND

The role of space suits in the prevention of orthopedic prosthetic joint infection remains unclear. Recent evidence suggests that space suits may in fact contribute to increased infection rates, with bioaerosol emissions from space suits identified as a potential cause. This study aimed to compare the particle and microbiological emission rates (PER and MER) of space suits and standard surgical clothing.

METHODS

A comparison of emission rates between space suits and standard surgical clothing was performed in a simulated surgical environment during 5 separate experiments. Particle counts were analyzed with 2 separate particle counters capable of detecting particles between 0.1 and 20 μm. An Andersen impactor was used to sample bacteria, with culture counts performed at 24 and 48 hours.

RESULTS

Four experiments consistently showed statistically significant increases in both PER and MER when space suits are used compared with standard surgical clothing. One experiment showed inconsistent results, with a trend toward increases in both PER and MER when space suits are used compared with standard surgical clothing.

CONCLUSION

Space suits cause increased PER and MER compared with standard surgical clothing. This finding provides mechanistic evidence to support the increased prosthetic joint infection rates observed in clinical studies.

Quality assessment of systematic reviews on total hip or knee arthroplasty using mod-AMSTAR

Background

Increasing numbers of systematic reviews (SRs) on total knee arthroplasty (TKA) and total hip arthroplasty (THA) have been published in recent years, but their quality has been unclear. The purpose of this study is to evaluate the methodological quality of SRs on TKA and THA.

Methods

We searched Ovid-Medline, Ovid-Embase, Cochrane Databases (including HTA, DARE, and CDSR), CBM, CNKI, Wang Fang, and VIP, from January 2014 to December 2015 for THA and TKA. The quality of SRs was assessed using the modified 25-item “Assessment of Multiple Systematic Reviews” (mod-AMSTAR) tool, which was based on the AMSTAR scale. A T-test, nonparametric test, and linear regression were conducted to assess the relationship between bibliographical characteristics and methodological quality.

Results

Sixty-three SRs were included, from which the majority of SRs (50, 79.4%) were conducted in Asia. Only 4 reviews were rated as high quality, and most were weak in providing a priori design (6, 9.5%), not limiting the publication type (8, 13%), providing an excluded primary studies list (4, 6.3%) and reporting support for the included primary studies (1, 1.6%). Reviews published in English journals performed better than did Chinese journals in duplicate data extraction (81.3% vs 46.7%, p = 0.017; 70.8% vs 33.3%, p = 0.009) and providing source of support for the SR (87.5% vs 33.3%, P < 0.001). Reviews published in journals with a higher impact factor were associated with a higher mod-AMSTAR score (regression coefficient: 0.38, 95%CI: 0.11–0.65; P = 0.006).

Conclusion

The methodological quality of the included SRs is far from satisfactory. Authors of SRs should conform to the recommendations outlined in the mod-AMSTAR items. Areas needing improvement were providing a priori design, not limiting the publication type, providing an excluded primary studies list, and reporting conflicts of interest.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0488-8) contains supplementary material, which is available to authorized users.

R3 Cup Does Not Have a High Failure Rate in Conventional Bearings: A Minimum of 5-Year Follow-Up

BACKGROUND

The R3 cementless acetabular system was first marketed in Australia and Europe in 2007. Previous papers have shown high failure rates of the R3 cup with up to 24% with metal-on-metal bearing. There are currently no medium term clinical results on this cup. The aim of the study is to review our results of the R3 acetabular cup with conventional bearings with a minimum of 5-year follow-up.

METHODS

Patients who were implanted with the R3 acetabular cup were identified from our center's arthroplasty database. A total of 293 consecutive total hip arthroplasties were performed in 286 patients. The primary outcome was revision. The secondary outcomes were the Oxford Hip Scores (OHS) and radiographic evaluation.

RESULTS

The mean age of the patients was 69.4 years. The mean preoperative OHS was 23 (range 10-34) and the mean OHS was 40 (range 33-48) at the final follow-up. Radiological evaluation showed an excellent ARA score in all patients at 5 years. None of the R3 cups showed osteolysis at the final follow-up. There were 3 revisions in our series, of which 2 R3 cups were revised. The risk of revision was 1.11% at 5 years.

CONCLUSION

Our experience of using the R3 acetabular system with conventional bearings showed high survivorship and is consistent with the allocated Orthopaedic Data Evaluation Panel rating of 5A* as rated in 2015 in the United Kingdom.

Choice of implant combinations in total hip replacement: systematic review and network meta-analysis

Objective To compare the survival of different implant combinations for primary total hip replacement (THR). Design Systematic review and network meta-analysis. Data sources Medline, Embase, The Cochrane Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, and the EU Clinical Trials Register.Review methods Published randomised controlled trials comparing different implant combinations. Implant combinations were defined by bearing surface materials (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, or metal-on-metal), head size (large ≥36 mm or small <36 mm), and fixation technique (cemented, uncemented, hybrid, or reverse hybrid). Our reference implant combination was metal-on-polyethylene (not highly cross linked), small head, and cemented. The primary outcome was revision surgery at 0-2 years and 2-10 years after primary THR. The secondary outcome was the Harris hip score reported by clinicians.Results 77 studies were included in the systematic review, and 15 studies (3177 hips) in the network meta-analysis for revision. There was no evidence that the risk of revision surgery was reduced by other implant combinations compared with the reference implant combination. Although estimates are imprecise, metal-on-metal, small head, cemented implants (hazard ratio 4.4, 95% credible interval 1.6 to 16.6) and resurfacing (12.1, 2.1 to 120.3) increase the risk of revision at 0-2 years after primary THR compared with the reference implant combination. Similar results were observed for the 2-10 years period. 31 studies (2888 patients) were included in the analysis of Harris hip score. No implant combination had a better score than the reference implant combination.Conclusions Newer implant combinations were not found to be better than the reference implant combination (metal-on-polyethylene (not highly cross linked), small head, cemented) in terms of risk of revision surgery or Harris hip score. Metal-on-metal, small head, cemented implants and resurfacing increased the risk of revision surgery compared with the reference implant combination. The results were consistent with observational evidence and were replicated in sensitivity analysis but were limited by poor reporting across studies.Systematic review registration PROSPERO CRD42015019435.

Cortisol inhibits mTOR signaling in avascular necrosis of the femoral head

BACKGROUND

ANFH is a major health problem, to which long lasting and definitive treatments are lacking. The aim of this study is to study RNA alterations attributed to cortisol-induced ANFH.

METHODS

Rat models were stratified into three groups: in vitro group (n = 20) for molecular biological assays, control group (n = 3), and ANFH group induced using lipopolysaccharide and dexamethasone (n = 3). Bone marrow-derived endothelial progenitor cells (BM-EPCs) were extracted from the rats. An RNA expression array was performed on BM-EPCs, and enriched genes were subject to pathway analysis. In vitro studies following findings of array results were also performed using the isolated BM-EPCs.

RESULTS

Significant alterations in mammalian target of rapamycin (mTOR) and HIF signaling pathways were identified in BM-EPCs of ANFH. By applying cortisol and dexamethasone to BM-EPCs, significant changes in mTOR and HIF elements were identified. The alteration of HIF pathways appeared to be downstream of mTOR signaling. Glucocorticoid receptor (GR) expression was related to glucocorticoid-dependent mRNA expression of mTOR/HIF genes. mTOR-dependent angiogenesis but not anabolism was the target of GR in ANFH. Inhibition of mTOR signaling also induced apoptosis of BM-EPCs via CHOP-dependent DR5 induction in response to GR stimulation.

CONCLUSION

Decreased mTOR signaling in response to GR stimulation leading to downregulated HIF pathway as well as increased apoptosis could be the pathophysiology.

Better early functional outcome after short stem total hip arthroplasty? A prospective blinded randomised controlled multicentre trial comparing the Collum Femoris Preserving stem with a Zweymuller straight cementless stem total hip replacement for the treatment of primary osteoarthritis of the hip

OBJECTIVES

Primary aim was to compare the functional results at 3 months and 2 years between short and conventional cementless stem total hip arthroplasty (THA). Secondary aim was to determine the feasibility of a double-blind implant-related trial.

DESIGN

A prospective blinded randomised controlled multicentre trial in patients with osteoarthritis of the hip. All patients, research assistants, clinical assessors, investigators and data analysts were blinded to the type of prosthesis.

POPULATION

150 patients between 18 and 70 years with osteoarthritis of the hip, 75 in the short stem and 75 in the conventional stem group. Mean age: 60 years (SD 7).

INTERVENTIONS

the Collum Femoris Preserving short stem versus the Zweymuller Alloclassic conventional stem.

MAIN OUTCOME MEASURES

The Dutch version of the Hip Disability and Osteoarthritis Outcome Score (HOOS). Secondary outcomes measures: Harris Hip Score, the Physical Component Scale of the SF12, the Timed Up and Go test, Pain and the EQ-5D. Feasibility outcomes: continued blinding, protocol adherence and follow-up success rate.

RESULTS

No significant difference between the two groups. Mean HOOS total score in the short stem group increased 32.7 points from 36.6 (95% CI 32.9 to 40.2) preoperatively to 69.3 (95% CI 66.4 to 72.1) at 3 months follow-up. Mean HOOS total score in the conventional straight stem group increased 36.3 points from 37.1 (95% CI 33.9 to 40.3) preoperatively to 73.4 (95% CI 70.3 to 76.4) at 3 months follow-up. 91.2% of patients remained blinded at 2 years follow-up. Both protocol adherence and follow-up success rate were 98%.

CONCLUSIONS

Functional result at 3 months and 2 years after short stem THA is not superior to conventional cementless THA. There were more perioperative and postoperative complications in the short stem group. Direct comparison of two hip implants in a double-blinded randomised controlled trial is feasible.

TRIAL REGISTRATION NUMBER

NTR1560.

Short stem total hip arthroplasty: Potential explanations for persistent post-surgical thigh pain

Short stem uncemented femoral implants were developed with the aim of preserving proximal bone stock for future revisions, improving biomechanical reconstruction, aiding insertion through smaller incisions and potentially decreasing or limiting the incidence of thigh pain. Despite all the advantages of short stem designs, it remains unclear whether they are able to limit post-surgical thigh pain. In patients with short stem hip arthroplasty and persistent thigh pain, it is of the utmost importance to understand the potential etiologies of this chronic pain for selecting the appropriate treatment strategy. Therefore, this manuscript explores the hypothetical etiologies of persistent thigh pain in short stem total hip arthroplasty, including both peripheral factors (structural or biomechanical causes) and central factors (involvement of the central nervous system). First, intrinsic causes (e.g. aseptic femoral loosening and prosthetic joint infection) and extrinsic sources (e.g. muscle pathology or spinal pathology) of persistent thigh pain related to hip arthroplasty are explained. In addition, other specific peripheral causes for thigh pain related to the short stem prosthetic reconstruction (e.g. stem malalignment and micro-motion) are unraveled. Second, the etiology of persistent thigh pain after short stem hip arthroplasty is interpreted in a broader concept than the biomechanical approach where peripheral structural injury is believed to be the sole driver of persistent thigh pain. Over the past decades evidence has emerged of the involvement of sensitization of central nervous system nociceptive pathways (i.e. central sensitization) in several chronic pain disorders. In this manuscript it is explained that there might be a relevant role for altered central nociceptive processing in patients with persistent pain after joint arthroplasty or revision surgery. Recognition of a potential role for centrally-mediated changes in pain processing in total hip replacement surgery has important implications for treatment. Comprehensive treatment addressing peripheral factors as well as neurophysiological changes occurring in the nervous system may help to improve outcomes in patients with short stem hip arthroplasty and chronic thigh pain. Working within a biopsychosocial approach in orthopaedic surgery, specifically in relation to total hip arthroplasty, could be very important and may lead to more satisfaction. Further research is warranted.

A bias-adjusted evidence synthesis of RCT and observational data: the case of total hip replacement

Evaluation of clinical effectiveness of medical devices differs in some aspects from the evaluation of pharmaceuticals. One of the main challenges identified is lack of robust evidence and a will to make use of experimental and observational studies (OSs) in quantitative evidence synthesis accounting for internal and external biases. Using a case study of total hip replacement to compare the risk of revision of cemented and uncemented implant fixation modalities, we pooled treatment effect estimates from OS and RCTs, and simplified existing methods for bias-adjusted evidence synthesis to enhance practical application. We performed an elicitation exercise using methodological and clinical experts to determine the strength of beliefs about the magnitude of internal and external bias affecting estimates of treatment effect. We incorporated the bias-adjusted treatment effects into a generalized evidence synthesis, calculating both frequentist and Bayesian statistical models. We estimated relative risks as summary effect estimates with 95% confidence/credibility intervals to capture uncertainty. When we compared alternative approaches to synthesizing evidence, we found that the pooled effect size strongly depended on the inclusion of observational data as well as on the use bias-adjusted estimates. We demonstrated the feasibility of using observational studies in meta-analyses to complement RCTs and incorporate evidence from a wider spectrum of clinically relevant studies and healthcare settings. To ensure internal validity, OS data require sufficient correction for confounding and selection bias, either through study design and primary analysis, or by applying post-hoc bias adjustments to the results. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd.

Efficacy of intra-articular magnesium for postoperative analgesia in total hip arthroplasty

The aim of the present study was to compare the efficacy of intra-articular magnesium sulphate and a saline placebo for postoperative pain control following total hip arthroplasty (THA). Sixty patients underwent THA and were randomly allocated into two groups to receive intra-articular injections of either 10 ml magnesium sulphate (100 mg/ml; magnesium group, n=30) or 10 ml normal saline solution (control group, n=30). Postoperative analgesia was maintained by intravenous morphine injection. The outcome measurements were visual analogue score (VAS), morphine consumption and Harris hip score (HHS). The two groups were well matched. The outcome of VAS at rest was significantly lower at postoperative hours 6 and 12 in the magnesium group as compared with the control group, although the difference was insignificant preoperatively and at postoperative hours 2, 4, 24 and 48, and days 3, 7 and 14. This indicator during activity was also lower in the magnesium group at postoperative hour 24 than that of the control group, although the difference was insignificant preoperatively and at hour 48, and days 7 and 14. The consumption of morphine (the total quantity) at 0-6, 6-12 and 0-48 h in the magnesium group was significantly lower than in the control group, although no significant differences were observed at 12-24 and 24-48 h between the groups. The improvements of HHS from preoperative to postoperative scores were statistically significant, however, no significant differences were identified between groups. Thus, the findings indicate that intra-articular magnesium sulphate injections provided improved pain control and reduced the need for morphine when compared with a saline placebo following THA.

The effect of intravertebral anesthesia on bone cement implantation syndrome in aged patients: A single-center 5-year retrospective study

The aim of the study was to assess the effect of commonly used intravertebral anesthesia on bone cement implantation syndrome (BCIS) in aged patients undergoing hemiarthroplasty.The medical records of 1210 aged patients receiving hemiarthroplasty under intravertebral anesthesia were retrospectively reviewed. Anesthesia charts for all patients were reviewed for central venous pressure, mean arterial pressure, arterial oxygen saturation, and heart rate before, during, and after cementation. Each patient was classified into no BCIS (grade 0) or BCIS grade 1, 2, or 3 according to the degree of hypotension, arterial desaturation, or loss of consciousness around cementation. Changes in these grades after cementation were compared according to the ways of intravertebral anesthesia used.Among all included patients, 72.2% (874/1210) showed grade 1 or higher grade of BCIS after cementation. Compared with spinal-epidural anesthesia, single epidural anesthesia showed adjusted odds ratios (95% confidence interval) of 1.25 (1.13-1.43) for grade 1, 1.36 (0.83-2.06) for grade 2, and 3.55 (1.52-7.06) for marked postoperatively grade 3 of BCIS versus grade 0 (Type III P < 0.0001).Single epidural anesthesia was associated with increased odds for elevation of these grades after cementation compared with spinal-epidural anesthesia.

Lifetime cost effectiveness of different brands of prosthesis used for total hip arthroplasty: a study using the NJR dataset

There is little evidence on the cost effectiveness of different brands of hip prostheses. We compared lifetime cost effectiveness of frequently used brands within types of prosthesis including cemented (Exeter V40 Contemporary, Exeter V40 Duration and Exeter V40 Elite Plus Ogee), cementless (Corail Pinnacle, Accolade Trident, and Taperloc Exceed) and hybrid (Exeter V40 Trilogy, Exeter V40 Trident, and CPT Trilogy). We used data from three linked English national databases to estimate the lifetime risk of revision, quality-adjusted life years (QALYs) and cost. For women with osteoarthritis aged 70 years, the Exeter V40 Elite Plus Ogee had the lowest risk of revision (5.9% revision risk, 9.0 QALYs) and the CPT Trilogy had the highest QALYs (10.9% revision risk, 9.3 QALYs). Compared with the Corail Pinnacle (9.3% revision risk, 9.22 QALYs), the most commonly used brand, and assuming a willingness-to-pay of £20,000 per QALY gain, the CPT Trilogy is most cost effective, with an incremental net monetary benefit of £876. Differences in cost effectiveness between the hybrid CPT Trilogy and Exeter V40 Trident and the cementless Corail Pinnacle and Taperloc Exceed were small, and a cautious interpretation is required, given the limitations of the available information. However, it is unlikely that cemented brands are among the most cost effective. Similar patterns of results were observed for men and other ages. The gain in quality of life after total hip arthroplasty, rather than the risk of revision, was the main driver of cost effectiveness. Cite this article: Bone Joint J 2015;97-B:762-70.