Survival outcomes of cemented compared to uncemented stems in primary total hip replacement

Hydroxyapatite ceramic-coated femoral components in younger patients followed up for 27 to 32 years

Aims

This study reports the results of 38 total hip arthroplasties (THAs) in 33 patients aged less than 50 years, using the JRI Furlong hydroxyapatite ceramic (HAC)-coated femoral component.

Methods

We describe the survival, radiological, and functional outcomes of 33 patients (38 THAs) at a mean follow-up of 27 years (25 to 32) between 1988 and 2018.

Results

Of the surviving 30 patients (34 THAs), there were four periprosthetic fractures: one underwent femoral revision after 21 years, two had surgical fixation as the stem was deemed stable, and one was treated nonoperatively due to the patient's comorbidities. The periprosthetic fracture patients showed radiological evidence of change in bone stock around the femoral stem, which may have contributed to the fractures; this was reflected in change of the canal flare index at the proximal femur. Two patients (two hips) were lost to follow-up. Using aseptic loosening as the endpoint, 16 patients (18 hips; 48%) needed acetabular revision. None of the femoral components were revised for aseptic loosening, demonstrating 100% survival. The estimate of the cumulative proportion surviving for revisions due to any cause was 0.97 (standard error 0.03).

Conclusion

In young patients with high demands, the Furlong HAC-coated femoral component gives excellent long-term results.

Outcomes Following Total Hip Arthroplasty in Patients Who Have Charcot Neuroarthropathy of the Hip

BACKGROUND

Historically, Charcot neuroarthropathy hip (CNH) was deemed a contraindication for total hip arthroplasty (THA). However, as implant design and surgical techniques advance, THA for CNH has been performed and documented in literature. Information regarding the outcomes of THA for CNH is limited. The objective of the study was to assess outcomes following THA in patients who have CNH.

METHODS

Patients who have CNH underwent primary THA and had at least 2 years of follow-up were identified in a national insurance database. For comparison, a 1:10 matched control cohort of patients who did not have CNH was created based on age, sex, and relevant comorbidities. Eight hundred and ninety-five CNH patients who underwent primary THA were compared to 8,785 controls. Medical outcomes, emergency department visits, hospital readmissions, and surgical outcomes including revisions between cohorts were evaluated using multivariate logistic regressions.

RESULTS

The CNH patients were found to have higher risks of 90-day wound complications (P = .014), periprosthetic joint infection (P = .013) (P = .021), dislocation (P < .001) (P < .001), aseptic loosening (P = .040) (P = .002), periprosthetic fracture (P = .003) (P < .001), and revision (P < .001) (P < .001) at 1-year and 2-year follow-up, respectively.

CONCLUSION

While patients who have CNH are at a higher risk of wound and implant-related complications, they are comparatively lower than previously reported in literature. Orthopaedic surgeons should be cognizant of the increased risk in this population to provide appropriate preoperative counseling and enhanced perioperative medical management.

Functional Outcome of Uncemented Total Hip Replacement in Low Socioeconomic Group Using Modified Harris Hip Score: A Prospective Midterm Follow-Up Study

Background Total hip replacement is a safe and effective surgery with excellent outcomes in most patients with hip arthritis. The aim of this study was to evaluate functional outcomes and complications of total hip replacement among patients with low socioeconomic status in India. Methods We assessed 50 patients whose incomes fell below the poverty line and who underwent uncemented total hip replacement. We used a modified Harris Hip Score, replacing two items (one measuring range of motion and one measuring deformity) with two new ones (one related to return to professional activity and another regarding sexual activity). Results At the final follow-up, patients' modified Harris Hip Score improved from a preoperative mean value of 13.28 (0-46) to a postoperative mean value of 88.52 (64-100), suggesting marked improvement in functional outcome (p<0.001). In total, 32 (64%) patients returned to their original profession, and 12 (24%) switched to alternate work with mild pain. All patients reported satisfaction with their sexual activity at the final follow-up. Conclusions Many patients in India whose income is below the poverty line work in manual labor professions (e.g., farmers, masons, and cobblers) that increase their risk of hip damage. Total hip replacement is beneficial for these patients, offering good personal and professional quality of life after the surgery.

Cemented Femoral Fixation in Total Hip Arthroplasty Reduces the Risk of Periprosthetic Femur Fracture in Patients 65 Years and Older: An Analysis from the American Joint Replacement Registry

BACKGROUND

Periprosthetic femur fracture (PPFx) is a devastating complication after total hip arthroplasty (THA). Despite concerns for increased PPFx, cementless fixation predominates in the United States (US). This study utilized the American Joint Replacement Registry (AJRR) to compare PPFx risk between cemented and cementless femoral fixation for THA.

METHODS

An analysis of primary THA cases in patients aged 65 years and older was performed with AJRR data linked to Centers for Medicare and Medicaid Services (CMS) data from 2012 to 2020. Analyses compared cemented to cementless femoral fixation. We identified 279,052 primary THAs, 266,040 (95.3%) with cementless and 13,012 (4.7%) with cemented femoral fixation. Cox proportional hazard regression analyses evaluated the association of fixation and PPFx risk, while adjusting for sex, age and competing risk of mortality. Cumulative incidence function (CIF) survival curves evaluated time to PPFx.

RESULTS

Age ≥ 80 years (P<0.0001) and women (P<0.0001) were associated with PPFx. Compared to cemented stems, cementless stems had an elevated risk of PPFx (Hazards Ratio 7.70, [95% Confidence interval 3.2-18.6], P<0.0001). The CIF curves demonstrated an increased risk for PPFx across all time points for cementless stems, with equal magnitude of risk to eight years.

CONCLUSION

Cementless femoral fixation in THA continues to predominate in the US, with cementless femoral fixation demonstrating increased risk of PPFx in patients 65 years or older. Surgeons should consider greater use of cemented femoral fixation in this population to decrease the risk of PPFx.

Clinical and Functional Outcomes of the Exeter V40 Short Stem in Primary and Revision Arthroplasty: Does the Indication Affect Outcomes in the Short Term?

Purpose

A variety of short Exeter stems designed specifically for use in performance of total hip arthroplasty (THA) in primary and revision settings have recently been introduced. Some have been used 'off label' for hip reconstruction. The aim of this study is to report clinical and radiological results from the Exeter V40 125 mm stem in performance of primary THA and revision THA.

Materials and Methods

This study had a retrospective design. Insertion of 58 (24 primary, 34 revision) Exeter V40 125 mm stems was performed between 2015 and 2017. The minimum follow-up period was two years. Assessment of the Oxford hip score (OHS), EuroQol-5 Dimension (EQ-5D), and radiological follow-up was performed at one and two years.

Results

In the primary group, the preoperative, mean OHS was 13.29. The mean OHS was 32.86 and 23.39 at one-year and two-year post-surgery, respectively. The mean EQ-5D-3L scores were at 0.14, 0.59, and 0.35, preoperatively, at one-year follow-up and two-year follow-up, respectively. In the revision group, the mean preoperative OHS was 19.41. The mean OHS was 30.55 and 26.05 at one-year and two-year post-surgery, respectively. The mean EQ-5D-3L scores were 0.33, 0.61, and 0.48 preoperatively, at one-year follow-up and two-year follow-up, respectively. No progressive or new radiolucent lines were observed around any stem at the time of the final follow-up in all patients in both groups.

Conclusion

Encouraging results regarding use of Exeter V40 125 mm stems have been reported up to two years following surgery in primary and revision THA settings.

The 45-year evolution of the Mathys RM monoblock cups: have the paradigm shifts been worthwhile?

INTRODUCTION

The Robert Mathys (RM) monoblock uncemented cup is a design less commonly used in primary total hip replacement. It's purported advantages over modular cemented cups are: (1) its modulus of elasticity approximating bone, thus mimicking load transmission and the biomechanical behaviour of the cup to better match stresses on the acetabulum, leading to bone-preservation; and (2) as a 1-piece cup there is absence of a mobile interface between a liner and shell, preventing backside wear. Since its inception in 1983 there have been 3 major design changes: the RM Classic, the RM Pressfit, and the RM Vitamys with the most modern polyethylene (vitamin E).

METHODS

In a retrospective cohort study of the New Zealand Joint Registry, all designs of RM acetabular cup were reviewed. Data were included from1998 to 2018. All-cause revision rates, reasons for revision and the Oxford Hip Score (OHS) were assessed.

RESULTS

In total 13,272 acetabular cups were included. The all-cause revision rates did not differ between the designs. Revision rates for aseptic loosening in the RM Vitamys were lower, but the follow-up was shorter and more larger heads were used. There was no difference in the OHS.

CONCLUSION

All implant designs were safe. The use of larger heads led to a decrease in revisions due to dislocation. It has to be waited out whether the RM Vitamys performs superior in the long-term due to the highly cross-linked polyethylene.

Are we getting better at cementing femoral stems in total hip arthroplasty? A 5-year institutional trend

INTRODUCTION

Femoral stem cementation provides excellent implant longevity with a low periprosthetic fracture rate among patients with compromised bone quality or abnormal anatomy. We radiologically evaluated the quality of the femoral cement mantle in patients undergoing THA to examine whether cementation quality improved with increased institutional experience.

METHODS

A retrospective study of 542 primary elective THAs performed using cemented stems from 2016 to 2021 at a high-volume orthopedic specialty center was conducted. Immediate post-operative anterior-posterior (AP) and lateral radiographs were evaluated to assess cement mantle quality based on the Barrack classification. Cement mantles were deemed satisfactory (Barrack A and B) or unsatisfactory (Barrack C and D). Regression was performed to identify predictors of unsatisfactory cementation quality.

RESULTS

The annual cemented primary THA volume increased throughout the study period from 14 cases in 2016 to 201 cases in 2021. Overall, the majority of cement mantles were deemed satisfactory; 91.7% on AP radiographs and 91.0% on lateral radiographs. Satisfactory cementation on AP radiograph achievement rates improved during the study period, which coincided with greater annual volume (p < 0.001). No association was found between posterior and direct anterior surgical approaches and satisfactory cementation quality on both AP and lateral radiographs.

CONCLUSION

Majority of femoral stems had satisfactory cementation quality. Higher institutional annual cemented THA volume was associated with improved cementation quality. Residency and fellowship training programs should place greater emphasis on the importance of femoral stem cementation for appropriately indicated patients.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Survival and performance of a dual tapered-wedge fully HA-coated press fit femoral stem

INTRODUCTION

Fully hydroxyapatite-coated titanium alloy double-tapered stems have been successful implant designs for THA. The Novation Element Stem (Exactech, Gainesville, FL) is one of several of these implants following a modified Corail design philosophy. Although a great deal is known about the results of the Corail stem, little is known about the more recent Corail-inspired implants. The authors evaluated the clinical outcomes, radiographic findings and survival statistics of the collarless version of the Element Stem when used routinely in a diverse patient population.

METHODS

A retrospective review was performed for all primary THR cases from 2010 to 2018. Patient demographics and HHS/OHS/patient satisfaction scores were obtained. Radiographs were evaluated for stem subsidence, radiolucencies, and bone responses to the implant.

RESULTS

One hundred and fifty seven Element Stems were implanted with greater than 2 years of radiographic follow-up, while 105 Element Stems implanted during the study period had a survival of 5 years or more. Average HHS was 91.7 and average OHS was 44.0. 54 of 157 hips had radiolucencies, all of which included a proximal zonal radiolucency. Average subsidence was 3.33 mm; 18 hips had subsidence > 4 mm. There were 8 revisions for: aseptic loosening (4), trauma-related peri-prosthetic fractures, and early proximal-medial fractures. At 5 years, the all-cause survival rate is 92.4%, 96.2% based only on aseptic loosening and 98.1% based only on proximal medial fractures.

CONCLUSION

Clinical outcomes using the collarless Novation Element Stem are good, but early proximal medial fracture is still a factor in patients with poor-quality bone. Proximal radiolucencies progressing to aseptic loosening post-operatively are also a concern. The 11.5% rate of subsidence is comparable to other fully HA-coated collarless stems. This study provides a thorough critical analysis of outcomes and midterm survival data of this dual tapered-wedge fully HA-coated collarless stem used routinely in a diverse patient population.

TOTAL HIP ARTHROPLASTY IN THE PUBLIC HEALTH SYSTEM OF SÃO PAULO: COMPARING TYPES OF FIXATION

ABSTRACT Brazil lacks registries on the prevalence of primary total hip arthroplasty (THA) fixation methods. Objective: (i) to describe the demographic profile of patients who underwent THA in the public health system of the municipality of São Paulo during the last 12 years and (ii) to compare fixation methods regarding costs, hospital stay length, and death rates. Methods: This is an ecological study conducted with data available on TabNet, a platform belonging to DATASUS. Public data (from the government health system) on THA procedures performed in São Paulo from 2008 to 2019 were extracted. Gender, age, city region, THA fixation method, number of surgeries, costs, hospital stay length, and death rates were analyzed. Results: We analyzed 7,673 THA, of which 6220 (81%) were performed via cementless/hybrid fixation and 1453 (19%), via the cemented technique. Cementless/hybrid fixation had a higher cost (US$ 495.27) than the cemented one (p < 0.001). Nevertheless, hospital stay length was 0.87 days longer for cemented fixation than the cementless/hybrid one. We found no significant difference in death rates between THA fixation methods. Conclusion: THA cementless/hybrid fixation is prevalent in the municipality of São Paulo, which had higher total costs and shorter hospitalizations than cemented fixation. We found no difference between THA fixation methods and death rates. Level of Evidence IV, Case Series.

How do 3D-printed primary uncemented acetabular components compare with established uncemented acetabular cups? The experience of the New Zealand National Joint Registry

BACKGROUND

3D-printed or additive manufactured acetabular implants are an exciting new technology being used in hip surgery with increasing frequency especially in complex acetabular reconstructions. However, the performance of acetabular components produced by this method for primary THR is unknown.

METHODS

41,272 uncemented cups in primary THR for OA were identified in the NZJR for the purposed of this study. There were 39,080 uncemented cups in the control group (15,798 Pinnacle cups, 12,724 Trident cups and 10,558 RM Pressfit cups) compared to 2192 3D-printed uncemented implants (1397 Delta TT cups, 640 Ti Por and 155 Polymax cups). All-cause revision rates and reasons for revision were examined. Kaplan-Meier survival analysis was performed.

RESULTS

3D-printed cups were inserted into younger, fitter patients with a higher mean BMI compared to those in the control group (p < 0.001). The overall all-cause revision rate for 3D-printed cups was not significantly different to the controls: 0.77/100 cys (95% CI 0.59-1) compared to 0.55/100 cys (95% CI 0.52-0.58) in the control group (p = 0.058, Hazards ratio 1.29, 95% CI 0.992-1.678). There was no difference in aseptic cup loosening or deep infection rates between either group or indeed individual implant designs.

CONCLUSIONS

3D-printed uncemented cups provide reliable survivorship and clinical results in primary THR comparable to established designs manufactured by traditional means. The theoretical concerns of increased rates of fatigue failure or deep infection are unsubstantiated.

The risk of revision following total hip arthroplasty in patients with inflammatory bowel disease, a registry based study

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the intestinal tract and is associated with decreased bone mineral density. IBD patients are at higher risk of osteopenia, osteoporosis and fracture compared to non-IBD patients. The impact of IBD on the performance of orthopedic implants has not been well studied. We hypothesized that a history of IBD at the time of primary total hip arthroplasty (THA) would increase the risk of subsequent failure as assessed by revision surgery. A retrospective implant survival analysis was completed using the Swedish Hip Arthroplasty Registry and the Sweden National Patient Register. A total of 150,073 patients undergoing THA for osteoarthritis within an 18-year period were included in the study. THA patients with (n = 2,604) and without (n = 147,469) a history of IBD at the time of THA were compared with primary revision as the main endpoint and adjusted using sex, age category and comorbidity (Elixhauser scores) as covariates. We found that patients with a history of IBD had a relatively higher risk of revision surgery for septic causes while the non-IBD patients had a relatively higher risk of revision for aseptic causes (p = 0.004). Our findings suggest there may be an association between gut health and THA performance.

Different Designs of Proximal Femoral Stems for Total Hip Arthroplasty: Mid-Term Clinical and Patient-Reported Functional Outcomes

INTRODUCTION

A comprehensive comparison of the performance of different femoral stem geometries in total hip arthroplasty (THA) is yet to be described. The primary aim of this study was to evaluate objective and subjective outcome measures in primary THA with different femoral implant styles.

METHODS

Stems were classified into the following five classes: cemented, conical, fit and fill, modular, and wedge. The objective outcomes of interest were the length of inpatient hospital stay (LOS), 90-day readmission rate, one-year revision rate, and two-year mortality rate. Preoperative and postoperative patient-reported outcome measures (PROMs), including hip disability and osteoarthritis outcome score (HOOS) - physical function shortform (HOOS-PS), patient-reported outcomes measurement information system physical function short form 10a (PROMIS PF-10a), and patient-reported outcomes measurement information system - short form - mental 10a (PROMIS M-10a) were recorded and compared between different classes.

RESULTS

Patients with a wedge stem had a significantly lower LOS versus every other stem group, while patients with a cemented stem had the highest LOS, approximately twofold that of the wedge stem group. Accounting for potential confounders, the conical and fit and fill groups had a significantly higher two-year mortality rate than the wedge stem group. Fit and fill stems conferred a slight risk of revision THA at one-year compared to wedge stems. There was no significant difference in the rates of failure to achieve the minimal clinically important difference (MCID) for the PROMs.

CONCLUSION

Placement of wedge stems resulted in a significantly lower LOS compared to every other stem class and a lower mortality rate than the conical, fit and fill, and modular stems. As for the 90-day readmission, one-year revision, and the rates of failure to achieve the MCID for general or hip-specific PROMs, stem design had no meaningful effect.

Use of a Plasma-Sprayed Titanium-Hydroxyapatite Femoral Stem in Hip Arthroplasty in Patients Older than 70 Years. Is Cementless Fixation a Reliable Option in the Elderly?

Background: Although cementless implants are increasing in popularity, the use of cementless femoral stems for total hip arthroplasty (THA) and hip hemiarthroplasty (HH) in elderly patients remains controversial. The aim of this study was to report the outcomes of a cementless stem used in a large multicentric cohort of elderly patients receiving elective THA and HH for displaced femoral neck fracture. Methods: A total of 293 patients (301 hips) aged 70 years or older (mean age, 78 years; range, 70–93) who received the same cementless plasma-sprayed porous titanium–hydroxyapatite stem were retrospectively evaluated after primary THA and HH to investigate stem survival, complications, and clinical and radiographic results. Results: Cumulative stem survival was 98.5% (95% CI, 96.4–99.4%; 91 hips at risks) with revision due to any reason as the end-point at 10-year follow-up (mean 8.6 years, range 4–12). No stem was revised due to aseptic loosening. The mean Forgotten Joint Score was 98.7. Radiographically, the implants showed complete osseointegration, with slight stress-shieling signs in less than 10% of the hips. Conclusion: The use of cementless stems was proven to be a reliable and versatile option even in elderly patients for elective THA and HH for femoral neck fracture.

Advancing of titanium medical implants by surface engineering: recent progress and challenges

Introduction:Titanium (Ti) and their alloys are used as main implant materials in orthopedics and dentistry for decades having superior mechanical properties, chemical stability and biocompatibility. Their rejections due lack of biointegration and bacterial infection are concerning with considerable healthcare costs and impacts on patients. To address these limitations, conventional Ti implants need improvements where the use of surface nanoengineering approaches and the development of a new generation of implants are recognized as promising strategies.Areas covered:This review presents an overview of recent progress on the application of surface engineering methods to advance Ti implants enable to address their key limitations. Several promising surface engineering strategies are presented and critically discussed to generate advanced surface properties and nano-topographies (tubular, porous, pillars) able not only to improve their biointegration, antibacterial performances, but also to provide multiple functions such as drug delivery, therapy, sensing, communication and health monitoring underpinning the development of new generation and smart medical implants.Expert opinion:Recent advances in cell biology, materials science, nanotechnology and additive manufacturing has progressively influencing improvements of conventional Ti implants toward the development of the next generation of implants with improved performances and multifunctionality. Current research and development are in early stage, but progressing with promising results and examples of moving into in-vivo studies an translation into real applications.

The lifetime risk of revision following total hip arthroplasty

AIMS

Joint registries typically use revision of an implant as an endpoint and report survival rates after a defined number of years. However, reporting lifetime risk of revision may be more meaningful, especially in younger patients. We aimed to assess lifetime risk of revision for patients in defined age groups at the time of primary surgery.

METHODS

The New Zealand Joint Registry (NZJR) was used to obtain rates and causes of revision for all primary total hip arthroplasties (THAs) performed between January 1999 and December 2016. The NZJR is linked to the New Zealand Registry of Births, Deaths and Marriages to obtain complete and accurate data. Patients were stratified by age at primary surgery, and lifetime risk of revision calculated according to age, sex, and American Society of Anesthesiologists (ASA) classification. The most common causes for revision were also analyzed for each age group.

RESULTS

The overall, ten-year implant survival rate was 93.6% (95% confidence interval (CI) 93.4% to 93.8%). It was lowest in the youngest age group (46 to 50 years), rising sequentially with increasing age to 97.5% in the oldest group (90 to 95 years). Lifetime risk of revision surgery was 27.6% (95% CI 27.3% to 27.8%) in those aged 46 to 50 years, decreasing with age to 1.1% (95% CI 0.0% to 5.8%) in those aged 90 to 95 years at the time of primary surgery. Higher ASA grades were associated with an increased lifetime risk of revision across all ages. The commonest causes for revision THA were aseptic loosening, infection, periprosthetic fracture, and dislocation.

CONCLUSION

When counselling patients preoperatively, the lifetime risk of revision may be a more meaningful and useful measure of longer-term outcome than implant survival at defined time periods. This study highlights the considerably increased likelihood of subsequent revision surgery in younger age groups. Cite this article: Bone Joint J 2021;103-B(3):479-485.

Assessment of Titanate Nanolayers in Terms of Their Physicochemical and Biological Properties

The surface modification of titanium substrates and its alloys in order to improve their osseointegration properties is one of widely studied issues related to the design and production of modern orthopedic and dental implants. In this paper, we discuss the results concerning Ti6Al4V substrate surface modification by (a) alkaline treatment with a 7 M NaOH solution, and (b) production of a porous coating (anodic oxidation with the use of potential U = 5 V) and then treating its surface in the abovementioned alkaline solution. We compared the apatite-forming ability of unmodified and surface-modified titanium alloy in simulated body fluid (SBF) for 1–4 weeks. Analysis of the X-ray diffraction patterns of synthesized coatings allowed their structure characterization before and after immersing in SBF. The obtained nanolayers were studied using Raman spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and scanning electron microscopy (SEM) images. Elemental analysis was carried out using X-ray energy dispersion spectroscopy (SEM EDX). Wettability and biointegration activity (on the basis of the degree of integration of MG-63 osteoblast-like cells, L929 fibroblasts, and adipose-derived mesenchymal stem cells cultured in vitro on the sample surface) were also evaluated. The obtained results proved that the surfaces of Ti6Al4V and Ti6Al4V covered by TiO₂ nanoporous coatings, which were modified by titanate layers, promote apatite formation in the environment of body fluids and possess optimal biointegration properties for fibroblasts and osteoblasts.

Periprosthetic fractures of the femur in primary total hip arthroplasty: a New Zealand Joint Registry analysis

BACKGROUND

Periprosthetic femoral fractures around total hip arthroplasty (THA) are increasing annually, and are a major cause for revision surgery in the New Zealand Joint Registry (NZJR). The aim of this study was to determine the timing and risk factors for periprosthetic femoral fractures in THA requiring revision surgery in the NZJR.

METHODS

All patients with a primary THA who sustained a periprosthetic femoral fracture requiring revision THA recorded in the NZJR were reviewed to determine age, gender, body mass index, American Society of Anesthesiologists (ASA) rating and femoral stem fixation (cemented or uncemented). Revision rates were calculated per 100 component years (cy), and risk factors determined in the first 90 days, and beyond.

RESULTS

Between 1999 and 2017, there were 713 revision THA for periprosthetic femoral fractures. Early revision THA was significantly associated with ASA score and body mass index ≥40. There was no gender difference (P = 0.274). The revision rate in uncemented femoral stems (1.12/100 cy) was significantly higher (p < 0.001) than cemented stems (0.16/100 cy). After 90 days, the revision rate was significantly higher with increasing age (P < 0.001), males (P < 0.001) and higher ASA score (P < 0.001). The difference between cemented (0.07/100 cy) and uncemented (0.05/100 cy) stems did not reach statistical significance (P = 0.108).

CONCLUSION

The rate of revision THA for periprosthetic femoral fracture is higher in uncemented femoral stems in the first 90 days, and is significantly associated with ASA score and morbid obesity. After 90 days, the rate is lower for uncemented femoral stems, but did not reach statistical significance.

Fixation Method and Subsequent Revision Rates for Elective Primary Hip Arthroplasty in People Aged 70 Years and Older: Analysis of National Administrative Data Sets by the UK Getting It Right First Time Program

BACKGROUND

We aimed to understand the role of fixation method in predicting subsequent revision rates in people aged 70 years and older undergoing elective primary total hip arthroplasty (THA) within the UK National Health Service (NHS).

METHODS

Data on elective primary THAs conducted in people aged 70 years and older between April 1, 2012, and March 31, 2018, and subsequent revisions conducted up to March 31, 2019, were extracted from the Hospital Episodes Statistics database for all NHS procedures in England. A flexible parametric competing risks model was used to identify the role of fixation method in predicting revision and adjust for age, sex, frailty, year of surgery, and all-cause mortality.

RESULTS

Data were available for 190,656 procedures. Crude revision rates at 1-7 years follow-up in those who had cemented, hybrid/reverse hybrid, and uncemented fixation were 1.8%, 1.8%, and 2.3%, respectively. There was a high level of variation between NHS trusts in the proportionate use of fixation method. The differences in the hazard of revision between uncemented and cemented fixation (hazard ratio, 1.238 [95% confidence interval, 1.148-1.336]) and hybrid/reverse hybrid fixation (hazard ratio, 1.184 [95% confidence interval, 1.082-1.297]) were both significant. In secondary analysis, there was evidence that revision rates in trusts where uncemented fixation predominated were not significantly lower for uncemented fixation compared to all other fixation methods.

CONCLUSIONS

Revision rates were significantly higher for elective primary THA in people aged 70 years and older who have uncemented fixation, compared to those who had cemented and hybrid/reverse hybrid fixation.

Revision Following Cemented and Uncemented Oxford-III Primary Medial Unicompartmental Knee Replacements: A 19-Year Analysis from the New Zealand Joint Registry

BACKGROUND

Oxford-III unicompartmental knee replacements (UKRs) are among the most commonly used prostheses to treat isolated medial compartment osteoarthritis (OA). However, the best mode of implant fixation for primary UKRs remains a source of debate. The hypothesis of this study was that the biologically superior fixation of uncemented Oxford-III primary UKRs would translate into a lower revision rate when compared with cemented Oxford-III primary UKRs used to treat isolated medial compartment OA.

METHODS

Data on all Oxford-III primary UKRs (n = 8,733) completed for isolated medial compartment OA from January 2000 to December 2018 were obtained from the New Zealand Joint Registry (NZJR). Revision rates were documented for each fixation type and analyzed for associations with patient sex and age at surgery. A multivariate Cox proportional-hazards analysis was completed to determine if type of fixation was an independent risk factor for revision of Oxford-III UKRs.

RESULTS

Statistical analysis revealed a >1.8-fold greater revision risk for cemented Oxford-III UKRs compared with uncemented Oxford-III UKRs (p = 0.001) when considered independently of other risk factors. Furthermore, compared with uncemented fixation, cemented fixation was associated with a 2.9-fold (p < 0.001) increase in revision risk for women <65 years old and a 1.7-fold (p = 0.008) increase in revision risk for men 55 to 74 years old. There was no significant difference in the risk of revision between fixation methods for women ≥65 years old and men ≥75 years old.

CONCLUSIONS

We found that the type of fixation was an independent risk factor for revision of Oxford-III UKRs used in the treatment of isolated medial compartment OA. Uncemented Oxford-III primary UKRs had superior implant survivorship in women <65 years old and men 55 to 74 years old. Age and sex are important factors to consider when determining the type of fixation for Oxford-III primary UKRs used to treat isolated medial compartment OA.

LEVEL OF EVIDENCE

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

Total Hip Arthroplasty in Patients With Sickle Cell Disease: A Comprehensive Systematic Review

BACKGROUND

Total hip arthroplasty (THA) is a common treatment for end-stage osteonecrosis of the hip in patients with sickle cell disease (SCD). This patient population presents unique challenges in the perioperative period. This systematic review aims to investigate the existing literature on the outcomes, complications, and survivorship of primary THA in SCD patients.

METHODS

A systematic search using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed of PubMed, MEDLINE, EMBASE, and Cochrane databases for clinical studies on THA in SCD patients. Studies on primary THA in SCD patients with a mean follow-up greater than 90 days were included.

RESULTS

Sixteen studies containing 5193 SCD patients met criteria for inclusion. The Coleman Quality of Evidence score ranged from poor to moderate. SCD patients had a significant increase in Harris Hip Scores and Merle d'Aubigne Scores after undergoing THA. Compared to non-SCD patients, SCD patients had increased hospital length-of-stay, 30-day and 90-day readmission rates, and rates of medical complications, including pain crises, acute chest syndrome, cardiac complications, sepsis, and mortality. SCD patients also had increased rates of surgical complications, including wound complications, infection, periprosthetic fracture, and aseptic loosening. Overall, THA revision rates were higher in SCD patients relative to those with primary osteoarthritis.

CONCLUSION

THA remains an effective treatment modality for osteonecrosis of the hip in SCD patients. However, these patients are at increased risk of medical and surgical complications. Surgeons should be aware of the unique challenges in this patient population when counseling and managing these patients in the perioperative period.

A Large-Scale Fifteen-Year Minimum Survivorship of a Cementless Triple Tapered Femoral Stem

BACKGROUND

This study reports the long-term outcomes of a metaphyseal fit-and-fill cementless femoral component in total hip arthroplasty (THA) with a follow-up of 15-19 years.

METHODS

We conducted a retrospective review of 376 consecutive THAs (345 patients), using a triple tapered stem performed between 2000 and 2003 with a view to assessing survivorship and radiological and functional outcomes. Images were assessed for initial alignment, terminal osteolysis, or subsidence, while clinical outcomes were assessed using the St Michael's Hip Score.

RESULTS

Forty-five (11.9%) hips were lost to follow-up, 20 (5.31%) had died before our 15-year cutoff follow-up, and 4 (1.06%) had declined follow-up early on, leaving 307 hips (81.64%, 276 patients) available for both clinical and radiological follow-up at a minimum of 15 years (range 15-19). The mean age at the time of operation was 49.6 years (range 19-71) and the cohort included 131 (42.67%) male and 145 (47.23%) female patients. Seven stems (2.28%) were revised: 4 due to periprosthetic fractures, 2 for periprosthetic joint infection, and 1 for adverse reaction to metal debris at the trunnion. The St Michael's Hip Score improved from 14.2 (range 9-23) preoperatively to 22.3 (range 13 to 25) at the last documented follow-up (P = .000). Kaplan-Meier survivorship with stem revision for any reason as the end point was 97.70%. Worst-case scenario Kaplan-Meier survivorship, where all lost to follow-up are considered as failures, was 85.3%. No stem was revised for aseptic loosening.

CONCLUSION

This triple tapered stem in THA shows excellent survivorship beyond a minimum of 15 years.

Short-term results of a new self-locking cementless femoral stem: a prospective cohort study of the Lima MasterSL

BACKGROUND

Total hip arthroplasty is a successful treatment for hip osteoarthritis. Primary and secondary implant fixation is dependent on implant design and plays an important role in the longevity of an implant. In this study, we assessed the self-locking cementless Master^SL femoral stem.

MATERIALS AND METHODS

In this single-centre prospective study, 50 consecutive hips with the indication for total hip arthroplasty, who met the inclusion criteria, received the Master^SL stem from LIMA Corporate. Patients had pre- and post-operative clinical and radiological assessment and completed patient-reported outcome measures [Oxford Hip Score (OHS), Harris Hip Score (HHS) and Forgotten Joint Score (FJS)] at the 6-week and 6-, 12- and 24-month mark. Post-operative X-rays were assessed for osteointegration (Engh Score), alignment and subsidence.

RESULTS

After 2 years, aseptic survival was 100%. One hip had to be explanted due to early deep infection and was excluded from the study. At 2 years, the patients reported a significant improved HHS and OHS of 95.3 ± 5.8 and 46.1 ± 3.6 (mean ± standard deviation), respectively, compared to preoperatively. The mean ± standard deviation for the FJS was 86.4 ± 18.7 with two-thirds of the patients reporting a score above 85. The mean Engh score is 15.1 ± 5.9 (mean ± standard deviation) with no patient scoring below 1 which suggests good osteointegration in all femoral stems.

CONCLUSIONS

The Master^SL femoral stem performed well in this short-term follow-up study, with high patient satisfaction and good signs of osteointegration. Long-term follow-up will be necessary to evaluate longevity.

LEVEL OF EVIDENCE

Level 3, Prospective cohort study.

TRIAL REGISTRATION

The study was registered on the 30.03.2016 with Australia New Zealand Clinical Trials Registry (ACTRN12617000550303).

Fixation, sex, and age: highest risk of revision for uncemented stems in elderly women - data from 66,995 primary total hip arthroplasties in the Norwegian Arthroplasty Register

Background and purpose - There is no consensus on best method of fixation in hip arthroplasty. We investigated different modes of fixation in primary total hip arthroplasty (THA) and the influence of age and sex, to assess need for a differentiated approach.Patients and methods - The study was based on data from the Norwegian Arthroplasty Register in the period 2005-2017. Included were all-cemented, all-uncemented, reverse hybrid (uncemented stem and cemented cup), and hybrid (cemented stem and uncemented cup) THA designs that were commonly used, contemporary and well documented, using different causes of revision as endpoints.Results - From the included 66,995 primary THAs, 2,242 (3.3%) were revised. Compared with all-cemented THAs, all-uncemented had a higher risk of revision due to any cause (RR 1.4; CI 1.2-1.6), mainly due to an increased risk of periprosthetic fracture (RR 5.2; CI 3.2-8.5) and dislocation (RR 2.2; CI 1.5-3.0). Women had considerably higher risk of revision due to periprosthetic fracture after all-uncemented THA (RR 12; CI 6-25), compared with cemented. All-uncemented THAs in women of age 55-75 years (RR 1.3; CI 1.0-1.7) and over 75 years of age (RR 1.8; CI 1.2-2.7), and reverse hybrid THAs in women over the age of 75 (RR 1.5; CI 1.1-1.9) had higher risk of revision compared with cemented. Hybrid THAs (RR 1.0; CI 0.9-1.2) and reverse hybrid THAs (RR 1.0; CI 0.7-1.3) had similar risk of revision due to any cause as cemented THAs.Interpretation - Uncemented stems (all-uncemented and reverse hybrid THAs) had increased risk of revision in women over 55 years of age, mainly due to periprosthetic fracture and dislocation, and should probably not be used in THA in these patients.

Albumin-Enriched Fibrin Hydrogel Embedded in Active Ferromagnetic Networks Improves Osteoblast Differentiation and Vascular Self-Organisation

Porous coatings on prosthetic implants encourage implant fixation. Enhanced fixation may be achieved using a magneto-active porous coating that can deform elastically in vivo on the application of an external magnetic field, straining in-growing bone. Such a coating, made of 444 ferritic stainless steel fibres, was previously characterised in terms of its mechanical and cellular responses. In this work, co-cultures of human osteoblasts and endothelial cells were seeded into a novel fibrin-based hydrogel embedded in a 444 ferritic stainless steel fibre network. Albumin was successfully incorporated into fibrin hydrogels improving the specific permeability and the diffusion of fluorescently tagged dextrans without affecting their Young’s modulus. The beneficial effect of albumin was demonstrated by the upregulation of osteogenic and angiogenic gene expression. Furthermore, mineralisation, extracellular matrix production, and formation of vessel-like structures were enhanced in albumin-enriched fibrin hydrogels compared to fibrin hydrogels. Collectively, the results indicate that the albumin-enriched fibrin hydrogel is a promising bio-matrix for bone tissue engineering and orthopaedic applications.

Risk factors for periprosthetic femoral fractures around total hip arthroplasty: a systematic review and meta-analysis

BACKGROUND

Periprosthetic fractures are becoming increasingly common, often leading to poor patient outcomes. The aim of this study was to identify risk factors associated with periprosthetic femoral fractures (PPFFx).

METHODS

Two independent reviewers conducted a systematic review of the databases MEDLINE, Embase and Cochrane Library according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, from the earliest available date to December 2017. We included all clinical articles reporting more than 100 post-operative PPFFx around total hip arthroplasty (THA). Outcomes included demographics, fracture type, risk factors and time to fracture.

RESULTS

A total of 12 868 PPFFx were reported across 18 eligible studies; 64% occurred following primary THA and 36% occurred after revision THA, and 66% of all fractures were in females. Vancouver B2 fractures were the most common type (39%). We found the odds of sustaining a PPFFx is significantly lower after a primary THA compared to revision THA (odds ratio 0.31, 95% confidence interval 0.24-0.40, P < 0.00001). The incidence of PPFFx is 2.96 per 1000 person-years following primary THA compared to 9.08 per 1000 person-years following revision THA (odds ratio 0.33, 95% confidence interval 0.27-0.40). The time to fracture was 6.03 years following primary THA and 4.08 years following revision THA. Gender and cementation did not significantly affect the odds of fracture.

CONCLUSION

The odds of sustaining a PPFFx following revision THA is three times greater compared to primary THA. Other risk factors including gender and cementation did not affect the odds of fracture.

Is single-anaesthetic bilateral total hip replacement using cemented stems safe and appropriate? A review of four decades of practice

BACKGROUND

Symptomatic bilateral hip osteoarthritis can be treated surgically with either staged or single-anaesthetic bilateral total hip replacement (BTHR). Today the typical candidate for BTHR is more likely to receive cementless implants. We present the experience of BTHR at our institution using cemented stems combined with cemented and uncemented sockets and, to our knowledge, the largest prospective single-centre series.

PATIENTS AND METHODS

This cohort study reviews all patients (319 patients: 638 hips) having BTHR at our institution between December 1977 and December 2015. No case was lost to follow-up. Data were collected prospectively but reviewed retrospectively. Length of stay and complication rates were included, and data were compared with Hospital Episode Statistics figures for operations carried out between March 2005 and June 2014 to confirm local database validity. Patient experience and Oxford Hip Scores were obtained for a subgroup of this cohort, comparing them with patients who underwent bilateral staged operations performed within 1 year.

RESULTS

The rates for mortality, deep vein thrombosis, non-fatal myocardial infarction within 6 months were each 0.3% (1 episode) and non-fatal pulmonary embolism 0.6% (2 episodes). There were no intraoperative periprosthetic fractures or readmissions within 30 days.

CONCLUSIONS

Our study shows a low risk of complications when using cemented and hybrid BTHRs for selected patients and the risk of complications compares favourably with published results. Available functional scores compared favourably to a comparison group of patients undergoing bilateral staged procedures, and a positive impression on treatment experience from a subgroup of interviewed BTHR patients was noticeable.

Implant Fixation and Risk of Prosthetic Joint Infection Following Primary Total Hip Replacement: Meta-Analysis of Observational Cohort and Randomised Intervention Studies

Prosthetic joint infection (PJI), although uncommon, is a dreaded and devastating complication of total hip replacement (THR). Whether implant-related factors, such as the fixation method, influences the risk of PJI following THR is contentious. We conducted a systematic review and meta-analysis to evaluate the body of evidence linking fixation methods (cemented, uncemented, hybrid, or reverse hybrid) with the risk of PJI following primary THR. Observational studies and randomised controlled trials (RCTs) comparing fixation methods, and reporting PJI incidence following THR, were identified through MEDLINE, Embase, Web of Science, Cochrane Library, and reference lists of relevant studies up to 24 April 2019. Summary measures were relative risks (RRs) (95% confidence intervals, CIs). We identified 22 eligible articles (based on 11 distinct observational cohort studies comprising 2,260,428 THRs and 4 RCTs comprising 945 THRs). In pooled analyses of observational studies, all cemented fixations (plain and antibiotic combined), plain cemented fixations, hybrid fixations, and reverse hybrid fixations were each associated with an increased overall PJI risk when compared with uncemented fixations: 1.10 (95% CI: 1.04–1.17), 1.50 (95% CI: 1.27–1.77), 1.49 (95% CI: 1.36–1.64), and 1.49 (95% CI: 1.14–1.95), respectively. However, in the first six months, uncemented fixations were associated with increased PJI risk when compared to all cemented fixations. Compared to antibiotic-loaded cemented fixations, plain cemented fixations were associated with an increased PJI risk (1.52; 95% CI: 1.36–1.70). One RCT showed an increased PJI risk comparing plain cemented fixations with antibiotic-loaded cemented fixations. Uncemented and antibiotic-loaded cemented fixations remain options for the prevention of PJI in primary THR.

Does the femoral offset affect replacements? The results from a National Joint Registry

BACKGROUND

Femoral component offset influences the torque forces exerted on a femoral stem and may therefore adversely affect femoral component survival. This study investigated the influence of femoral component offset on revision rates for primary total hip replacements (THR) registered on the New Zealand Joint Registry (NZJR).

METHODS

There were 106,139 primary THRs registered, resulting in 4960 revisions for any cause. There were 46,242 THRs performed using the five commonest femoral components listed on the NZJR. A total of 41,100 were done for primary osteoarthritis of which 40,548 had all the offset information available for analysis. We defined low offset as < 42 mm, standard as 42-48 mm and high offset as > 48 mm offset and examined revision rates according to the reasons for revision. We performed survival analyses for both cemented and uncemented femoral components grouped by the different offsets.

RESULTS

The all-cause revision rate was 0.54/100 component years (cys). Stems with < 42 mm offset had a revision rate of 0.58/100 cys (mean 0.58; 95% confidence interval (CI) 0.53-0.63), 42-48 mm offset 0.47 (95% CI 0.43-0.52) and > 48 mm offset 0.67 (95% CI 0.57-0.79). There was no significant difference in all-cause revision rates between varying stem offsets in uncemented stems adjusting for age and gender. In cemented stems both high and low offset stems were more likely to be revised. Uncemented stems of all offsets were more likely to undergo revision for femoral fracture.

CONCLUSIONS

Femoral component offset affects the overall all-cause revision rate of the most commonly used cemented stem, but not uncemented stem designs. In cemented stems offset influences the rate of revision for loosening and periprosthetic fractures.

The Morphology, Structure, Mechanical Properties and Biocompatibility of Nanotubular Titania Coatings before and after Autoclaving Process

The autoclaving process is one of the sterilization procedures of implantable devices. Therefore, it is important to assess the impact of hot steam at high pressure on the morphology, structure, and properties of implants modified by nanocomposite coatings. In our works, we focused on studies on amorphous titania nanotubes produced by titanium alloy (Ti6Al4V) electrochemical oxidation in the potential range 5⁻60 V. Half of the samples were drying in argon stream at room temperature, and the second ones were drying additionally with the use of immersion in acetone and drying at 396 K. Samples were subjected to autoclaving and after sterilization they were structurally and morphologically characterized using Raman spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) and scanning electron microscopy (SEM). They were characterized in terms of wettability, mechanical properties, and biocompatibility. Obtained results proved that the autoclaving of amorphous titania nanotube coatings produced at lower potentials (5⁻15 V) does not affect their morphology and structure regardless of the drying method before autoclaving. Nanotubular coatings produced using higher potentials (20⁻60 V) require removal of adsorbed water particles from their surface. Otherwise, autoclaving leads to the destruction of the architecture of nanotubular coatings, which is associated with the changing of their mechanical and biointegration properties.

Periprosthetic fracture fixation of the femur following total hip arthroplasty: A review of biomechanical testing - Part II

BACKGROUND

Periprosthetic femoral fracture is a severe complication of total hip arthroplasty. A previous review published in 2011 summarised the biomechanical studies regarding periprosthetic femoral fracture and its fixation techniques. Since then, there have been several commercially available fracture plates designed specifically for the treatment of these fractures. However, several clinical studies still report failure of fixation treatments used for these fractures.

METHODS

The current literature on biomechanical models of periprosthetic femoral fracture fixation since 2010 to present is reviewed. The methodologies involved in the experimental and computational studies of periprosthetic femoral fracture fixation are described and compared with particular focus on the recent developments.

FINDINGS

Several issues raised in the previous review paper have been addressed by current studies; such as validating computational results with experimental data. Current experimental studies are more sophisticated in design. Computational studies have been useful in studying fixation methods or conditions (such as bone healing) that are difficult to study in vivo or in vitro. However, a few issues still remain and are highlighted.

INTERPRETATION

The increased use of computational studies in investigating periprosthetic femoral fracture fixation techniques has proven valuable. Existing protocols for testing periprosthetic femoral fracture fixation need to be standardised in order to make more direct and conclusive comparisons between studies. A consensus on the 'optimum' treatment method for periprosthetic femoral fracture fixation needs to be achieved.

Fourteen-year experience with short cemented stems in total hip replacement

PURPOSE

The age of the population requiring total hip replacement (THR) is increasing and this may lead to a return of cemented stems. Advantages of a short cemented femoral device include preservation of metaphyseal bone, easier insertion, and easier cement removal in case of revision. The purpose of this study is to describe the rationale and assess midterm results of unique innovative short cemented double-tapered polished stem applied with contemporary cementing techniques.

METHODS

Our experience with this short cemented stem includes two different groups of elderly patients. Group 1 (prototype version of the short stem) from January 2005 to January 2008 counts 43 THR. Group 2 (final commercial version of the short stem) from January 2013 to January 2015 counts 54 THR. The average age in groups 1 and 2 was 79 and 75 respectively. Patients underwent clinical follow-up with the Harris Hip Score (HHS) and completed radiographic evaluation.

RESULTS

Thirty-one patients of group 1 had died for reasons unrelated to their THR. The surviving 9 hips have a follow-up of 11.2 years. In group 2, eight  patients died for reasons unrelated to their THR. Follow-up for the surviving 40 patients is 4.6 years. HHS improved in both groups. In 34/43 hips of group 1 and in 41/54 of group 2 we observed a Barrack grade A cement mantle. Survival with revision of the stem for aseptic loosening as the endpoint was 100%.

CONCLUSIONS

This study confirms the effectiveness of a short, polished, collarless, tapered cemented stem implanted with contemporary cementing techniques which appears as successful as the standard sized components.

A Wedge-Shaped Uncemented Femoral Component: Survivorship in Patients Younger Than 50 Years at a Mean Follow-Up of 22 Years

BACKGROUND

This study presents the results of the long-term survival of a wedge-shaped uncemented femoral component in a cohort of young patients with a follow-up of 20-25 years.

METHODS

In a consecutive series of 85 patients (100 hips), aged less than 50 years at the time of primary total hip arthroplasty, the long-term survival of the Cementless Spotorno femoral component was analyzed by performing a Kaplan-Meier survival analysis (95% confidence interval [CI]).

RESULTS

The mean follow-up was 22 years (range, 19.7-25.5). The clinical and radiographic outcomes were satisfactory. The overall survival rate of the femoral component was 93.4% after 23.8 years (95% CI, 85.9%-97.0%). Survival with revision for aseptic loosening as the end point was 94.4% (95% CI, 87.0%-97.6%) after 23.8 years.

CONCLUSION

This study shows an excellent long-term survival of this specific wedge-shaped uncemented femoral component after 20 to 25 years in patients younger than 50 years.

Reverse hybrid total hip arthroplasty

Aims

This study aimed to evaluate implant survival of reverse hybrid total hip arthroplasty (THA) at medium-term follow-up.

Patients and Methods

A consecutive series of 1082 THAs in 982 patients with mean follow-up of 7.9 years (5 to 11.3) is presented. Mean age was 69.2 years (21 to 94). Of these, 194 (17.9%) were in patients under 60 years, 663 (61.3%) in female patients and 348 (32.2%) performed by a trainee. Head size was 28 mm in 953 hips (88.1%) or 32 mm in 129 hips (11.9%). Survival analysis was performed and subgroups compared using log rank tests.

Results

Ten-year survival (122 hips at risk) was 97.2% (95% confidence interval (CI) 95.77 to 98.11) for all-cause revision. There was no difference in survival by age (p = 0.50), gender (p = 0.78), head size (p = 0.63) or surgeon grade (p = 0.36). No acetabular components underwent revision for aseptic loosening in the entire series. Four (0.4%) aseptic stem failures occurred early at a mean of 2.5 years (0.6 to 4.8) and were associated with age under 60 years (p = 0.015). There was no difference in survival by gender (p = 0.12), head size (p = 0.43) or surgeon grade (p = 0.77) for stem revision.

Conclusion

This is the largest reported study into reverse hybrid THA and it confirms successful outcomes, irrespective of age, gender, head size and surgeon grade. Cite this article: Bone Joint J 2018;100-B:1010-17.

Antibacterial surface modification of titanium implants in orthopaedics

The use of biomaterials in orthopaedics for joint replacement, fracture healing and bone regeneration is a rapidly expanding field. Infection of these biomaterials is a major healthcare burden, leading to significant morbidity and mortality. Furthermore, the cost to healthcare systems is increasing dramatically. With advances in implant design and production, research has predominately focussed on osseointegration; however, modification of implant material, surface topography and chemistry can also provide antibacterial activity. With the increasing burden of infection, it is vitally important that we consider the bacterial interaction with the biomaterial and the host when designing and manufacturing future implants. During this review, we will elucidate the interaction between patient, biomaterial surface and bacteria. We aim to review current and developing surface modifications with a view towards antibacterial orthopaedic implants for clinical applications.

Human Skeletal Stem Cell Response to Multiscale Topography Induced by Large Area Electron Beam Irradiation Surface Treatment

The healthcare socio-economic environment is irreversibly changing as a consequence of an increasing aging population, consequent functional impairment, and patient quality of life expectations. The increasing complexity of ensuing clinical scenarios compels a critical search for novel musculoskeletal regenerative and replacement strategies. While joint arthroplasty is a highly effective treatment for arthritis and osteoporosis, further innovation and refinement of uncemented implants are essential in order to improve implant integration and reduce implant revision rate. This is critical given financial restraints and the drive to improve cost-effectiveness and quality of life outcomes. Multi-scale modulation of implant surfaces, offers an innovative approach to enhancement in implant performance. In the current study, we have examined the potential of large area electron beam melting to alter the surface nanotopography in titanium alloy (Ti6Al4V). We evaluated the in vitro osteogenic response of human skeletal stem cells to the resultant nanotopography, providing evidence of the relationship between the biological response, particularly Collagen type I and Osteocalcin gene activation, and surface nanoroughness. The current studies demonstrate osteogenic gene induction and morphological cell changes to be significantly enhanced on a topography Ra of ~40 nm with clinical implications therein for implant surface treatment and generation.

Effects of interfacial micromotions on vitality and differentiation of human osteoblasts

Objectives

Enhanced micromotions between the implant and surrounding bone can impair osseointegration, resulting in fibrous encapsulation and aseptic loosening of the implant. Since the effect of micromotions on human bone cells is sparsely investigated, an in vitro system, which allows application of micromotions on bone cells and subsequent investigation of bone cell activity, was developed.

Methods

Micromotions ranging from 25 µm to 100 µm were applied as sine or triangle signal with 1 Hz frequency to human osteoblasts seeded on collagen scaffolds. Micromotions were applied for six hours per day over three days. During the micromotions, a static pressure of 527 Pa was exerted on the cells by Ti6Al4V cylinders. Osteoblasts loaded with Ti6Al4V cylinders and unloaded osteoblasts without micromotions served as controls. Subsequently, cell viability, expression of the osteogenic markers collagen type I, alkaline phosphatase, and osteocalcin, as well as gene expression of osteoprotegerin, receptor activator of NF-κB ligand, matrix metalloproteinase-1, and tissue inhibitor of metalloproteinase-1, were investigated.

Results

Live and dead cell numbers were higher after 25 µm sine and 50 µm triangle micromotions compared with loaded controls. Collagen type I synthesis was downregulated in respective samples. The metabolic activity and osteocalcin expression level were higher in samples treated with 25 µm micromotions compared with the loaded controls. Furthermore, static loading and micromotions decreased the osteoprotegerin/receptor activator of NF-κB ligand ratio.

Conclusion

Our system enables investigation of the behaviour of bone cells at the bone-implant interface under shear stress induced by micromotions. We could demonstrate that micromotions applied under static pressure conditions have a significant impact on the activity of osteoblasts seeded on collagen scaffolds. In future studies, higher mechanical stress will be applied and different implant surface structures will be considered.

Cite this article: J. Ziebart, S. Fan, C. Schulze, P. W. Kämmerer, R. Bader, A. Jonitz-Heincke. Effects of interfacial micromotions on vitality and differentiation of human osteoblasts. Bone Joint Res 2018;7:187–195. DOI: 10.1302/2046-3758.72.BJR-2017-0228.R1.

Biomechanics of a cemented short stem: Standard vs. line-to-line cementation techniques. A biomechanical in-vitro study involving six osteoporotic pairs of human cadaver femurs

BACKGROUND

Short-stem total hip arthroplasty (THA) potentially offers advantages compared to conventional THA, including sparing bone and soft tissue and being a facilitated and less traumatic implantation. However, the indication is limited to patients with sufficient bone quality. Cemented short-stem THA might provide an alternative to conventional cemented THA. To date, no cemented short stem is available on the market.

METHODS

In the present in vitro study, primary stability of a new cemented short stem was evaluated, comparing standard (undersized stem) versus line-to-line (same-sized stem) cementing techniques, using six pairs of human cadaver femurs. Primary stability, including reversible micromotion and irreversible migration, was assessed in a dynamic material-testing machine. Fracture load was tested and fracture pattern analyzed.

FINDINGS

Both cementation techniques (standard vs. line-to-line) displayed comparable results with respect to primary stability without any statistical differences (micromotion: 17.5 μm vs. 9.6 μm (p = 0.063); migration: 9.5 μm vs. 38.2 μm (p = 0.188)). Regarding fracture load, again, no difference was observed (3670 N vs. 3687 N (p = 0.063)). In all cases, proximal fractures of Vancouver type B3 occurred.

INTERPRETATION

The present in vitro study demonstrates that the line-to-line cementation technique, which is favourable regarding the philosophy of short stem THA, can be further pursued in the course of the development of a cemented short stem. Further investigations should address how well the cemented short stem compares to well-established cemented straight-stem designs.

Nano-carrier based drug delivery systems for sustained antimicrobial agent release from orthopaedic cementous material

Total joint replacement (TJR), such as hip and knee replacement, is a popular procedure worldwide. Prosthetic joint infections (PJI) after this procedure have been widely reported, where treatment of such infections is complex with high cost and prolonged hospital stay. In cemented arthroplasties, the use of antibiotic loaded bone cement (ALBC) is a standard practice for the prophylaxis and treatment of PJI. Recently, the development of bacterial resistance by pathogenic microorganisms against most commonly used antibiotics increased the interest in alternative approaches for antimicrobial delivery systems such as nanotechnology. This review summarizes the efforts made to improve the antimicrobial properties of PMMA bone cements using nanotechnology based antibiotic and non-antibiotic delivery systems to overcome drawbacks of ALBC in the prophylaxis and treatment of PJIs after hip and knee replacement.

Total hip arthroplasty: a still evolving technique

It has been advocated that total hip arthroplasty (THA) is probably the most successful surgical intervention performed in Medicine. In the 1960s, Sir John Charnley not only introduced, but also modified and improved the technique of cemented arthroplasties. The concepts on biological fixation established by Pillar and Galante served as the foundation for the development of uncemented implants that are now used worldwide. Currently, THA is a worldwide widespread surgery performed on millions of people. However, keeping abreast of the large number of information available on these procedures, especially on implant fixation, designs, different tribological pairings, and the long-term results can be challenging at times. This article is a brief update on the main aspects of THA.

Acetabulum-Only Revision Total Hip Arthroplasty Is Associated With Good Functional Outcomes and Survivorship

BACKGROUND

The coexistence of a stable femoral and a loose acetabular component may pose a clinical dilemma for the surgeon. Our study aims at comparing the intermediate functional outcomes and survivorship of acetabulum-only revision total hip arthroplasty (ArTHA) with an age-matched and gender-matched total revision THA (TrTHA) group.

METHODS

We retrospectively reviewed prospectively collected data on the pain, function, and total Harris Hip Scores (HHS) and complication profile for ArTHA and TrTHA cohorts from our regional arthroplasty database. Kaplan-Meier survivorship, with the need for repeat revision surgery as the end point, was used for survival analysis.

RESULTS

Among 538 cases, there were fewer acute medical complications in ArTHA and a similar dislocation rate for both cohorts. Preoperative HHS for pain, function, and total were better in the ArTHA cohort, but only the function score reached statistical significance. No significant differences in subsequent years for all aspects of HHS, except the function score was significantly better in the ArTHA cohort at year 1. And 10.0% of ArTHAs and 7.8% of TrTHAs had required rerevision. The 5-year survivorship was 90.3% (95% confidence interval ± 2.1%) for the ArTHA cohort and 92.7% (95% confidence interval ± 1.8%) for the TrTHA cohort (P = .394). The ArTHA with posterior approach (n = 118) group had the lowest dislocation rate and the best trend of functional outcomes.

CONCLUSION

ArTHA can provide similar functional outcomes and dislocation rate to TrTHA, with an acceptable rerevision rate. The posterior approach in this study was not associated with a significant dislocation rate.

Micromotion-induced peri-prosthetic fluid flow around a cementless femoral stem

Micromotion-induced interstitial fluid flow at the bone-implant interface has been proposed to play an important role in aseptic loosening of cementless implants. High fluid velocities are thought to promote aseptic loosening through activation of osteoclasts, shear stress induced control of mesenchymal stem cells differentiation, or transport of molecules. In this study, our objectives were to characterize and quantify micromotion-induced fluid flow around a cementless femoral stem using finite element modeling. With a 2D model of the bone-implant interface and full-factorial design, we first evaluated the relative influence of material properties, and bone-implant micromotion and gap on fluid velocity. Transverse sections around a femoral stem were built from computed tomography images, while boundary conditions were obtained from experimental measurements on the same femur. In a second step, a 3D model was built from the same data-set to estimate the shear stress experienced by cells hosted in the peri-implant tissues. The full-factorial design analysis showed that local micromotion had the most influence on peak fluid velocity at the interface. Remarkable variations in fluid velocity were observed in the macrostructures at the surface of the implant in the 2D transverse sections of the stem. The 3D model predicted peak fluid velocities extending up to 2.2 mm/s in the granulation tissue and to 3.9 mm/s in the trabecular bone. Peak shear stresses on the cells hosted in these tissues ranged from 0.1 to 12.5 Pa. These results offer insight into mechanical stimuli encountered at the bone-implant interface.

Comparative Study of Surgical Management of Fracture Neck of Femur with Cemented Versus Uncemented Bipolar Hemiarthroplasty

INTRODUCTION

There is evidence for use of cemented hemiarthroplasty resulting in greater anchoring and lesser peri prosthetic fracture. However, this procedure results in more haemodynamic instability and cardiopulmonary complications termed as 'cement reaction' or bone cement implantation syndrome. There has been a heightened interest among surgeons to compare cemented and uncemented hemiarthroplasty for fracture neck of femur.

AIM

To compare cemented and uncemented hemiarthroplasty in terms of blood loss during the procedure, post-operative complications, mortality, functional recovery and long term clinical outcome.

MATERIALS AND METHODS

In a prospective study spanning 8 years from January 2006 to January 2014 in a tertiary care hospital, 52 cases of fracture of neck were selected. Twenty four patients underwent cemented and 28 patients underwent uncemented hemiarthroplasty. Mean follow up duration was 59.3 months. Harris Hip Score evaluation was done at each follow up. Radiological evaluation was done at each follow up for calcar length and periprosthetic fractures.

RESULTS

Mean age of patients was 70 years. Harris Hip scores at 3, 6 and 12 months did not show statistically significant differences. Periprosthetic osteolysis or loosening was not seen in the present study. No complications noted in uncemented hemiarthroplasty. Four patients who had cemented hemiarthroplasty had infections. No mortality occurred during admission and within 12 months after surgery.

CONCLUSION

No significant difference was noted between the cemented and uncemented hemiarthroplasty procedures on long term follow up in terms of functionality. No re-operations and no mortality reported. Cemented hemiarthroplasty had more blood loss and minimal post-operative complications.

UNCEMENTED ARTHROPLASTY AFTER HIP METASTATIC DISEASE AND MULTIPLE MYELOMA

Objective:

To describe a case series using a combination of narrative, graphical exploratory analysis and Bayesian Network modeling.

Methods:

Case series with 34 patients undergoing uncemented and hybrid arthroplasty procedures secondary to hip pain or fracture secondary to metastatic disease or multiple myeloma.

Results:

The most common tumors included gastrointestinal, multiple myeloma and breast cancer. Most devices were total arthroplasty (n = 16, 84.2%) rather than partial and uncemented arthroplasty (n = 12, 63.2%) rather than hybrid. The average time between surgery and deambulation was 20 days, the average length of hospital stay was 13 days, and the average patient survival was 589 days. Only one infection was reported. Uncemented and hybrid arthroplasty devices did not differ regarding time to walk, as well as the length of hospital stay in this sample.

Conclusion:

Our model may be used as a prior for the addition of subsequent patient samples, personalizing, thus, its recommendations to other patient populations. Level of Evidence IV, Case series.