Hip replacement

Engineering immunomodulatory and osteoinductive implant surfaces via mussel adhesion-mediated ion coordination and molecular clicking

Immune response and new tissue formation are important aspects of tissue repair. However, only a single aspect is generally considered in previous biomedical interventions, and the synergistic effect is unclear. Here, a dual-effect coating with immobilized immunomodulatory metal ions (e.g., Zn²⁺) and osteoinductive growth factors (e.g., BMP-2 peptide) is designed via mussel adhesion-mediated ion coordination and molecular clicking strategy. Compared to the bare TiO₂ group, Zn²⁺ can increase M2 macrophage recruitment by up to 92.5% in vivo and upregulate the expression of M2 cytokine IL-10 by 84.5%; while the dual-effect of Zn²⁺ and BMP-2 peptide can increase M2 macrophages recruitment by up to 124.7% in vivo and upregulate the expression of M2 cytokine IL-10 by 171%. These benefits eventually significantly enhance bone-implant mechanical fixation (203.3 N) and new bone ingrowth (82.1%) compared to the bare TiO₂ (98.6 N and 45.1%, respectively). Taken together, the dual-effect coating can be utilized to synergistically modulate the osteoimmune microenvironment at the bone-implant interface, enhancing bone regeneration for successful implantation.

Immune response and new tissue formation are important aspects of tissue repair but often only one aspect is considered in biomedical interventions. Here, the authors report on the use of a mussel-like surface coating to immobilize immune modulating metal ions and growth factors and demonstrated improved in vivo outcomes.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Socioeconomic status and use of analgesic drugs before and after primary hip arthroplasty: a population-based cohort study of 103,209 patients during 1996-2018

Background and purpose - Total hip arthroplasty (THA) is an effective and common procedure. However, persistent pain and analgesic requirement up to 2 years after THA surgery are common. We examined the trends in the utilization of analgesics before and after THA, overall, and in relation to socioeconomic status (SES) in a populationbased cohort. Patients and methods - We used the Danish Hip Arthroplasty Register to identify 103,209 patients who underwent THA between 1996 and 2018. Data on prescriptions and SES markers was obtained from Danish medical databases. Prevalence rates of redeemed prescriptions for analgesics with 95% confidence intervals were calculated for 4 quarters before and 4 quarters after THA for the entire THA population, and by 3 SES markers (education, cohabiting status, and wealth). Results - Overall, the prevalence of analgesic use prior to surgery was 42% at 9-12 months and 59% at 0-3 months before the THA. The prevalence of analgesics reached its highest at 64% 0-3 months after THA but declined to 27% at 9-12 months after THA. Low education, living alone, and having low wealth (low SES) were associated with higher prevalence of analgesics use both before and after THA. Interpretation - 59% of patients used analgesics 0-3 months before surgery, which could indicate that THA might not be considered the last option for treatment and that surgery criteria might depend more on factors such as patient preferences or hip function. Moreover, health professionals should prioritize the use of a detailed plan when phasing out analgesics after THA to counteract unnecessary use, especially when treating patients with low SES.

The role of nanopores constructed on micropitted titanium surface on immune responses of macrophages and the potential mechanisms

Delayed transition of pro-inflammatory M1 to pro-healing M2 of macrophages (MΦs) on implant surface is one of the most important reasons accounting for poor osseointegration. The present work proposes to...

Postoperative Patient-reported Pain and Opioid Consumption After Total Hip Arthroplasty: A Comparison of the Direct Anterior and Posterior Approaches

INTRODUCTION

Although one of the touted benefits of the direct anterior approach (DAA) includes decreased postoperative pain, there is no consensus on the effect of surgical approach on postoperative pain and subsequent analgesic consumption.

METHODS

Consecutive patients undergoing total hip arthroplasty by a single surgeon from May 2016 to March 2020 were identified. Procedures were categorized as DAA or posterior approach. Patient demographics and surgical details were assessed. Patient-reported maximum pain by postoperative day (POD), total opioid consumption during hospitalization, and whether the patient required a refill of opioid prescription within 3 months after discharge were compared between the two surgical approaches through multivariate analyses.

RESULTS

A total of 611 patients were included in this study (447 DAA and 164 posterior approaches). On multivariate analyses that controlled for preoperative/intraoperative differences, patients in the DAA group had lower average maximum reported pain (0 to 10 scale) on POD #0 (6.5 versus 6.8, P = 0.034) and POD #1 (5.4 versus 6.1, P = 0.018). However, the DAA was not associated with a statistically significant reduction in total inpatient oral morphine equivalents consumed (79.8 versus 100.1, P = 0.486). Furthermore, there was no association between surgical approach and opioid prescription refill within 3 months after discharge (P = 0.864).

DISCUSSION

The DAA was associated with slightly lower patient-reported pain. Furthermore, statistical analysis did not provide the necessary evidence to reject the null hypothesis, which was that there would be no difference in opioid utilization between the two approaches. Other perioperative factors may be more important to opioid use reduction than the surgical approach alone.

A Critical Review of the Design, Manufacture, and Evaluation of Bone Joint Replacements for Bone Repair

With the change of people’s living habits, bone trauma has become a common clinical disease. A large number of bone joint replacements is performed every year around the world. Bone joint replacement is a major approach for restoring the functionalities of human joints caused by bone traumas or some chronic bone diseases. However, the current bone joint replacement products still cannot meet the increasing demands and there is still room to increase the performance of the current products. The structural design of the implant is crucial because the performance of the implant relies heavily on its geometry and microarchitecture. Bionic design learning from the natural structure is widely used. With the progress of technology, machine learning can be used to optimize the structure of bone implants, which may become the focus of research in the future. In addition, the optimization of the microstructure of bone implants also has an important impact on its performance. The widely used design algorithm for the optimization of bone joint replacements is reviewed in the present study. Regarding the manufacturing of the implant, the emerging additive manufacturing technique provides more room for the design of complex microstructures. The additive manufacturing technique has enabled the production of bone joint replacements with more complex internal structures, which makes the design process more convenient. Numerical modeling plays an important role in the evaluation of the performance of an implant. For example, theoretical and numerical analysis can be carried out by establishing a musculoskeletal model to prepare for the practical use of bone implants. Besides, the in vitro and in vivo testing can provide mechanical properties of bone implants that are more in line with the implant recipient’s situation. In the present study, the progress of the design, manufacture, and evaluation of the orthopedic implant, especially the joint replacement, is critically reviewed.

Use of muscular flaps for the treatment of hip prosthetic joint infection: a systematic review

BACKGROUND

Deep periprosthetic infection after total hip arthroplasty (THA) is a serious and challenging complication for the orthopedic surgeon. Muscular flaps may represent a valid management option for the treatment of this condition. We present a systematic literature review about the use of muscular flaps for the treatment of hip prosthetic joint infection.

METHODS

The review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seventy-seven articles, out of 279 titles, were considered eligible for the full-text analysis. Finally 15 studies that met inclusion criteria were included in this review.

RESULTS

Overall, 210 patients (49% males, 48.6% females and 2.4% not reported) suffering from THA infection treated with muscular flaps were collected. The mean age was 69.6 years. Mean follow-up, reported in all studies, was 3.3 years. The results presented by the different authors, highlight the effectiveness of muscular flaps for the treatment of periprosthetic infection, in terms of function, limb salvage, prevention of the recurrences, cost-effectiveness, and quality of life postoperatively.

CONCLUSIONS

Muscle flaps provide an excellent management option for patients with persistent infection after total hip arthroplasty.

Effect of an Elevated Preoperative International Normalized Ratio on Transfusion and Complications in Primary Total Hip Arthroplasty with the Enhanced Recovery after Surgery Protocol

Objective

To verify whether an elevated preoperative international normalized ratio (INR) increases transfusion and complications independently in primary total hip arthroplasty (THA) with the management of an enhanced recovery after surgery (EARS) protocol.

Methods

We retrospectively reviewed the database of adults who underwent primary THA between 2014 and 2018 by the same surgeon. A total of 552 patients were assigned into three groups by preoperative INR class: INR ≤ 0.9, 0.9 < INR < 1.0, and INR ≥ 1.0. We regarded transfusion within 90 days during the same hospitalization as the primary outcome. We also included perioperative blood loss, maximum Hb drop, postoperative anaemia requiring medicine, and length of hospital stay (LOS) during the same hospitalization in the study. Complications and reoperation at 90 days and mortality at 90 days and 12 months were also included in the study. Univariable analyses were utilized to compare baselines and outcomes among the three groups. Multivariate logistic regressions were used to adjust for differences at baseline among the groups.

Results

All patients had an INR < 1.5 preoperatively and were managed with the ERAS protocol. Among them, 93 (16.8%) patients had INR ≤ 0.9, 268 (48.6%) patients had 0.9 < INR < 1.0, and 191 (34.6%) patients had INR ≥ 1.0. In the univariable analyses, as the INR increased, the transfusion rates increased from 1.08% for INR ≤ 0.9, to 1.12% for 0.9 < INR < 1.0 and to 5.76% for INR ≥ 1.0 (P < 0.05). The overall complication rate increased from 10.8% for INR ≤ 0.9, to 16.4% for 0.9 < INR < 1.0, and to 22.5% for INR ≥ 1.0 (P < 0.05). The length of stay (LOS) in the INR ≥ 1.0 group was 5.7 ± 2.2 days, which was significantly longer than that in the INR ≤ 0.9 group (4.7 ± 1.6 days, P = 0.000) and 0.9 < INR < 1.0 group (5.1 ± 2.0 days, P = 0.007). No statistical significance was detected among the groups regarding blood loss, maximum Hb drop, or the incidence of postoperative anaemia that required medicine. There was no significant difference in reoperation or mortality among the groups. When controlling for demographic and comorbidity characteristics, there was no statistically significant difference in the odds of transfusion during the same hospitalization or overall complications at 90 days among the groups (P > 0.05).

Conclusions

Elevated preoperative INR cannot increase transfusion or complication rates independently in primary THA with the management of the ERAS protocol. With the improvement in the ERAS protocol and the use of tranexamic acid (TXA), an INR < 1.5 is still a conventional safe threshold for THA surgery.

Capacitive interdigitated system of high osteoinductive/conductive performance for personalized acting-sensing implants

Replacement orthopedic surgeries are among the most common surgeries worldwide, but clinically used passive implants cannot prevent failure rates and inherent revision arthroplasties. Optimized non-instrumented implants, resorting to preclinically tested bioactive coatings, improve initial osseointegration but lack long-term personalized actuation on the bone-implant interface. Novel bioelectronic devices comprising biophysical stimulators and sensing systems are thus emerging, aiming for long-term control of peri-implant bone growth through biointerface monitoring. These acting-sensing dual systems require high frequency (HF) operations able to stimulate osteoinduction/osteoconduction, including matrix maturation and mineralization. A sensing-compatible capacitive stimulator of thin interdigitated electrodes and delivering an electrical 60 kHz HF stimulation, 30 min/day, is here shown to promote osteoconduction in pre-osteoblasts and osteoinduction in human adipose-derived mesenchymal stem cells (hASCs). HF stimulation through this capacitive interdigitated system had significant effects on osteoblasts' collagen-I synthesis, matrix, and mineral deposition. A proteomic analysis of microvesicles released from electrically-stimulated osteoblasts revealed regulation of osteodifferentiation and mineralization-related proteins (e.g. Tgfb3, Ttyh3, Itih1, Aldh1a1). Proteomics data are available via ProteomeXchange with the identifier PXD028551. Further, under HF stimulation, hASCs exhibited higher osteogenic commitment and enhanced hydroxyapatite deposition. These promising osteoinductive/conductive capacitive stimulators will integrate novel bioelectronic implants able to monitor the bone-implant interface and deliver personalized stimulation to peri-implant tissues.

Association between surgeon grade and implant survival following hip and knee replacement: a systematic review and meta-analysis

OBJECTIVE

To investigate the association between surgeon grade (trainee vs consultant) and implant survival following primary hip and knee replacement.

DESIGN

A systematic review and meta-analysis of observational studies.

DATA SOURCES

MEDLINE and Embase from inception to 6 October 2021.

SETTING

Units performing primary hip and/or knee replacements since 1990.

PARTICIPANTS

Adult patients undergoing either a primary hip or knee replacement, predominantly for osteoarthritis.

INTERVENTION

Whether the surgeon recorded as performing the procedure was a trainee or not.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was net implant survival reported as a Kaplan-Meier survival estimate. The secondary outcome was crude revision rate. Both outcomes were reported according to surgeon grade.

RESULTS

Nine cohort studies capturing 4066 total hip replacements (THRs), 936 total knee replacements (TKRs) and 1357 unicompartmental knee replacements (UKRs) were included (5 THR studies, 2 TKR studies and 2 UKR studies). The pooled net implant survival estimates for THRs at 5 years were 97.9% (95% CI 96.6% to 99.2%) for trainees and 98.1% (95% CI 97.1% to 99.2%) for consultants. The relative risk of revision of THRs at 5 and 10 years was 0.88 (95% CI 0.46 to 1.70) and 0.68 (95% CI 0.37 to 1.26), respectively. For TKRs, the net implant survival estimates at 10 years were 96.2% (95% CI 94.0% to 98.4%) for trainees and 95.1% (95% CI 93.0% to 97.2%) for consultants. We report a narrative summary of UKR outcomes.

CONCLUSIONS

There is no strong evidence in the existing literature that trainee surgeons have worse outcomes compared with consultants, in terms of the net survival or crude revision rate of hip and knee replacements at 5-10 years follow-up. These findings are limited by the quality of the existing published data and are applicable to countries with established orthopaedic training programmes.

PROSPERO REGISTRATION NUMBER

CRD42019150494.

A novel efficient and precise technique for removing acetabular osteophytes in patients undergoing total hip arthroplasty: the SH-9Hospital acetabular edge file

Background

Total hip arthroplasty (THA) is frequently performed in patients with end-stage hip disease. Periacetabular osteophytes are common during THA; however, these osteophytes should be removed intraoperatively to avoid potential impingement between osteophytes and femoral prostheses and decrease dislocation risk. There are no current standard procedures or surgical technique criteria to remove these osteophytes. Osteophytes around the acetabulum are usually removed with an osteotome, yet this presents certain disadvantages. Hence, this study aimed to introduce a novel and more efficient technique than the aforementioned one, the SH-9Hospital acetabular edge file.

Methods

Fifty-four patients (54 hips) who underwent primary THA using osteotome and the SH-9Hospital acetabular edge file to remove periacetabular osteophytes intraoperatively were retrospectively studied. Clinical and radiographic data were obtained for all patients intra- and postoperatively.

Results

The mean osteophyte removal time was 274.6±102.7 s and 51.3±21.1 s in the osteotome and SH-9Hospital acetabular edge file groups, respectively. Intraoperative images and postoperative radiographs showed that acetabular osteophytes were removed thoroughly and precisely by the acetabular edge file and that there was no iatrogenic injury and prostheses malposition in both groups.

Conclusions

The SH-9Hospital acetabular edge file was a novel, efficient, highly precise, and repeatable method for removing periacetabular osteophytes in patients undergoing total hip arthroplasty.

Total hip arthroplasty versus progressive resistance training in patients with severe hip osteoarthritis: protocol for a multicentre, parallel-group, randomised controlled superiority trial

INTRODUCTION

Hip osteoarthritis (OA) is the leading cause for total hip arthroplasty (THA). Although, being considered as the surgery of the century up to 23% of the patients report long-term pain, and deficits in physical function and muscle strength may persist after THA. Progressive resistance training (PRT) appears to improve multiple outcomes moderately in patients with hip OA. Current treatment selection is based on low-level evidence as no randomised controlled trials have compared THA to non-surgical treatment. The primary aim of this trial is to investigate whether THA followed by standard care is superior to 12 weeks of supervised PRT followed by 12 weeks of optional unsupervised PRT for improving hip pain and function in patients with severe hip OA.

METHODS AND ANALYSIS

This is a protocol for a multicentre, parallel-group, assessor-blinded, randomised controlled superiority trial conducted at four hospitals across three healthcare regions in Denmark. 120 patients aged ≥50 years with clinical and radiographic hip OA found eligible for THA by an orthopaedic surgeon will be randomised to THA followed by standard care, or 12 weeks of PRT (allocation 1:1). The primary outcome will be change in patient-reported hip pain and function, measured using the Oxford Hip Score, from baseline to 6 months after initiating the treatment. Key secondary outcomes will be change in the Hip disability and Osteoarthritis Outcome Score subscales, University of California Los Angeles Activity Score, 40 m fast-paced walk test, 30 s chair stand test and occurrence of serious adverse events. Patients declining participation in the trial will be invited into a prospective observational cohort study.

ETHICS AND DISSEMINATION

The trial has been approved by The Regional Committees on Health Research Ethics for Southern Denmark (Project-ID: S-20180158). All results will be presented in peer-reviewed scientific journals and international conferences.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT04070027).

A micro/nano-biomimetic coating on titanium orchestrates osteo/angio-genesis and osteoimmunomodulation for advanced osseointegration

Osseointegration is a sophisticated bone and implant healing process comprising of initial hematoma formation, immediate osteoimmunomodulation, angiogenesis, and osteogenesis. To fulfill rapid and satisfying osseointegration, this study developed a biomimetic implant coating that could confer the intraosseous implants a systematical regulation of the participatory processes. Herein, we shaped dissimilar nano-scale (NS) to form highly biomimetic structures of natural extracellular matrix (ECM) of the host bone and bone healing hematoma with micro/nano-scale (MNS) titania fiber-like network on the surface of titanium (Ti) implants. In vitro experiments revealed that the MNS not only facilitated osteogenic and angiogenic differentiation of bone marrow stromal cells (BMSCs) and endothelial cells, respectively, but also suppressed M1 macrophages (MΦs), whereas, stimulated pro-healing M2 phenotype. Notably, BMSCs on MNS surfaces enabled a significant immunomodulatory effect on MΦs resulting in the downregulation of inflammation-related cell signaling pathways. The favorable osteoimmune microenvironment manipulated by MNS further facilitated osteo-/angio-genesis via the crosstalk of multi-signaling pathways. In vivo evaluation mirrored the aforementioned results, and depicted that MNS induced ameliorative osseointegration when compared with the NS as well as the pristine Ti implant. The study demonstrated the modulatory effect of the multifaceted biomimetic structure on spatiotemporal regulation of the participatory processes during osseointegration.

Is the Preoperative Use of Antidepressants and Benzodiazepines Associated with Opioid and Other Analgesic Use After Hip and Knee Arthroplasty?

BACKGROUND

Mental health disorders can occur in patients with pain conditions, and there have been reports of an increased risk of persistent pain after THA and TKA among patients who have psychological distress. Persistent pain may result in the prolonged consumption of opioids and other analgesics, which may expose patients to adverse drug events and narcotic habituation or addiction. However, the degree to which preoperative use of antidepressants or benzodiazepines is associated with prolonged analgesic use after surgery is not well quantified.

QUESTION/PURPOSES

(1) Is the preoperative use of antidepressants or benzodiazepine medications associated with a greater postoperative use of opioids, NSAIDs, or acetaminophen? (2) Is the proportion of patients still using opioid analgesics 1 year after arthroplasty higher among patients who were taking antidepressants or benzodiazepine medications before surgery, after controlling for relevant confounding variables? (3) Does analgesic drug use decrease after surgery in patients with a history of antidepressant or benzodiazepine use? (4) Does the proportion of patients using antidepressants or benzodiazepines change after joint arthroplasty compared with before?

METHODS

Of the 10,138 patients who underwent hip arthroplasty and the 9930 patients who underwent knee arthroplasty at Coxa Hospital for Joint Replacement, Tampere, Finland, between 2002 and 2013, those who had primary joint arthroplasty for primary osteoarthritis (64% [6502 of 10,138] of patients with hip surgery and 82% [8099 of 9930] who had knee surgery) were considered potentially eligible. After exclusion of another 8% (845 of 10,138) and 13% (1308 of 9930) of patients because they had revision or another joint arthroplasty within 2 years of the index surgery, 56% (5657 of 10,138) of patients with hip arthroplasty and 68% (6791 of 9930) of patients with knee arthroplasty were included in this retrospective registry study. Patients who filled prescriptions for antidepressants or benzodiazepines were identified from a nationwide drug prescription register, and information on the filled prescriptions for opioids (mild and strong), NSAIDs, and acetaminophen were extracted from the same database. For the analyses, subgroups were created according to the status of benzodiazepine and antidepressant use during the 6 months before surgery. First, the proportions of patients who used opioids and any analgesics (that is, opioids, NSAIDs, or acetaminophen) were calculated. Then, multivariable logistic regression adjusted with age, gender, joint, Charlson Comorbidity Index, BMI, laterality (unilateral/same-day bilateral), and preoperative analgesic use was performed to calculate odds ratios for any analgesic use and opioid use 1 year postoperatively. Additionally, the proportion of patients who used antidepressants and benzodiazepines was calculated for 2 years before and 2 years after surgery.

RESULTS

At 1 year postoperatively, patients with a history of antidepressant or benzodiazepine use were more likely to fill prescriptions for any analgesics than were patients without a history of antidepressant or benzodiazepine use (adjusted odds ratios 1.9 [95% confidence interval 1.6 to 2.2]; p < 0.001 and 1.8 [95% CI 1.6 to 2.0]; p < 0.001, respectively). Similarly, patients with a history of antidepressant or benzodiazepine use were more likely to fill prescriptions for opioids than patients without a history of antidepressant or benzodiazepine use (adjusted ORs 2.1 [95% CI 1.7 to 2.7]; p < 0.001 and 2.0 [95% CI 1.6 to 2.4]; p < 0.001, respectively). Nevertheless, the proportion of patients who filled any analgesic prescription was smaller 1 year after surgery than preoperatively in patients with a history of antidepressant (42% [439 of 1038] versus 55% [568 of 1038]; p < 0.001) and/or benzodiazepine use (40% [801 of 2008] versus 55% [1098 of 2008]; p < 0.001). The proportion of patients who used antidepressants and/or benzodiazepines was essentially stable during the observation period.

CONCLUSION

Surgeons should be aware of the increased risk of prolonged opioid and other analgesic use after surgery among patients who were on preoperative antidepressant and/or benzodiazepine therapy, and they should have candid discussions with patients referred for elective joint arthroplasty about this possibility. Further studies are needed to identify the most effective methods to reduce prolonged postoperative opioid use among these patients.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Comorbidity indices in orthopaedic surgery: a narrative review focused on hip and knee arthroplasty

Comorbidity indices currently used to estimate negative postoperative outcomes in orthopaedic surgery were originally developed among non-orthopaedic patient populations.

While current indices were initially intended to predict short-term mortality, they have since been used for other purposes as well.

As the rate of hip and knee arthroplasty steadily rises, understanding the magnitude of the effect of comorbid disease on postoperative outcomes has become increasingly more important.

Currently, the ASA classification is the most commonly used comorbidity measure and is systematically recorded by the majority of national arthroplasty registries.

Consideration should be given to developing an updated, standardized approach for comorbidity assessment and reporting in orthopaedic surgery, especially within the setting of elective hip and knee arthroplasty.

Cite this article: EFORT Open Rev 2021;6:629-640. DOI: 10.1302/2058-5241.6.200124

Preoperative bacteriuria positivity on urinalysis increases wound complications in primary total hip arthroplasty regardless of the urine culture result

BACKGROUND

Current evidence does not recommend screening urine culture and curing asymptomatic bacteriuria (ASB) before joint arthroplasty. The bacteriuria count on pre-operative urinalysis is a more common clinical parameter. We aimed to investigate whether the bacteriuria count on preoperative urinalysis can increase postoperative wound complications in primary total hip arthroplasty (THA).

METHODS

We conducted a retrospective study that included patients who underwent primary THA in our institution from 2012 to 2018. We obtained preoperative urinalysis results before THA during the same hospitalization and identified patients with abnormal urinalysis. Receiver operating characteristic (ROC) curves were first generated to evaluate the predicted value of leukocyte esterase (LE), nitrite, bacteriuria, and pyuria in the urinalysis for superficial wound infection. Then, all included patients were divided into two groups according to the preoperative urinalysis: a bacteriuria-positive group and a bacteriuria-negative group. The primary outcome was the superficial wound infection rate within 3 months postoperatively, and the secondary outcomes included wound leakage, prosthetic joint infection (PJI), pulmonary infection, urinary tract infection (UTI), readmission rate within 3 months postoperatively, and length of stay (LOS) during hospitalization. We utilized univariable analyses to compare the outcomes between the two groups. A multivariable logistic regression model was generated to explore the potential association between bacteriuria and the risk of superficial wound infection, wound leakage, and readmission rate controlling for baseline values.

RESULTS

A total of 963 patients were included in the study. One hundred sixty patients had abnormal urinalysis. The AUCs for LE, nitrite, bacteriuria, and pyuria were 0.507 (95% confidence interval (CI), 0.315 to 0.698), 0.551 (0.347 to 0.756), 0.675 (0.467 to 0.882), and 0.529 (0.331 to 0.728), respectively. Bacteriuria was diagnostically superior to LE, nitrite, and pyuria. Among the 963 patients, 95 had a positive bacteriuria on preoperative urinalysis, and only 9 (9.5%) had a positive urine culture. Compared with the bacteriuria-negative group, the bacteriuria-positive group had a higher superficial wound infection rate (4.2% vs. 0.6%, P = 0.008), higher wound leakage rate (11.6% vs. 4.5%, P = 0.007), higher readmission rate (5.3% vs. 1.3%, P = 0.015) within 3 months postoperatively and longer LOS (6.19 ± 2.89 days vs. 5.58 ± 2.14 days, P = 0.011). After adjustment, the bacteriuria-positive group had a significantly increased risk of superficial wound infection (OR = 7.587, 95%CI: 2.002 to 28.755, P = 0.003), wound leakage (OR = 3.044, 95%CI: 1.461 to 6.342, P = 0.003), and readmission (OR = 4.410, 95%CI: 1.485 to 13.097, P = 0.008).

CONCLUSION

Preoperative bacteriuria positivity on urinalysis significantly increased the risk of postoperative wound complications, readmission, and LOS in primary THA regardless of the result of the urine culture. Urinalysis is a fast and cost-acceptable test whose advantages have been underestimated.

LEVEL OF EVIDENCE

Level III, observational study.

Capsular repair vs capsulectomy in total hip arthroplasty

BACKGROUND

A major complication of total hip arthroplasty is dislocation. The hip joint capsule can be incised and repaired, or can be excised.

SOURCES OF DATA

We performed a systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines focusing on capsular repair and capsulectomy.

AREAS OF AGREEMENT

We identified 31 articles (17 272 patients). Capsular repair produced a lower blood loss (465.2 vs 709.2 ml), and the procedure lasted 102.5 vs 96.08 min in patients who underwent capsulectomy. The patients undergoing capsulectomy experienced a dislocation rate of 3.06%, whereas in the patients undergoing capsular repair, the dislocation rate was 0.65%.

AREAS OF CONTROVERSY

Most studies are retrospective observational studies, with no prospective randomized trials.

GROWING POINTS

Capsular preservation is association with a lower dislocation rate and a lower blood loss. Capsular excision does take statistically less time, but it is uncertain how a 6 min difference is clinically relevant.

AREAS TIMELY FOR DEVELOPING RESEARCH

Appropriately powered randomized clinical trials should be conducted to better define the association between the chosen implants, approach and outcome.

Reporting of Comorbidities in Total Hip and Knee Arthroplasty Clinical Literature: A Systematic Review

BACKGROUND

The effects of comorbid disease remain an area of interest. Concurrent diagnoses not only affect clinical outcomes but also affect health-care reimbursement. As the rate of arthroplasty increases, consistent risk stratification is imperative. Therefore, our aim was to ascertain how comorbidities have been reported in the recent total hip arthroplasty (THA) and total knee arthroplasty (TKA)-related literature; we also wanted to quantify the use of comorbidity scores for the assessment of comorbid disease in arthroplasty research.

METHODS

A systematic review of the recent THA and TKA literature that was published between January 1, 2019, and September 21, 2020, was performed using the PubMed and MEDLINE databases. Clinical studies that provided data on comorbidities were evaluated for method of comorbidity reporting. The prevalence of comorbidity reporting was assessed, and the manner of reporting was analyzed.

RESULTS

Among 659 articles, a total of 207 studies (31.4%) reported comorbidities and met our inclusion criteria. Of the 207 studies that reported comorbidities, only 57% used a comorbidity index to report comorbid disease. Of all of the indices, the American Society of Anesthesiologists (ASA) Physical Status Classification System was the score that was most commonly used (TKA, 86.2%; THA, 83.3%). Additional scores were used at varying frequencies. For TKA, the scores included the Charlson Comorbidity Index (CCI) (15.5%); the New York Heart Association (NYHA) Functional Classification (3.4%); and the CCI-Deyo (adapted by Deyo et al.), the age-adjusted CCI, the Cumulative Illness Rating Scale (CIRS), and the Readmission Risk Assessment Tool (RRAT) (1.7% each). For THA, the scores included the CCI (16.7%), the Elixhauser Comorbidity Measure (ECM) (6.7%), and the CCI-Deyo (1.7%).

CONCLUSIONS

Considering the impact of comorbid disease on outcomes, complications, and, ultimately, reimbursement, standardized risk stratification in arthroplasty is necessary. Current studies demonstrate inconsistent comorbidity reporting, making it challenging to further characterize the impact of comorbidities on outcomes. Future research should target the development of a standardized data-driven model for comorbidity assessment in the orthopaedic patient population.

Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation

Instrumented implants can improve the clinical outcome of total hip replacements (THRs). To overcome the drawbacks of external energy supply and batteries, energy harvesting is a promising approach to power energy-autonomous implants. Therefore, we recently presented a new piezoelectric-based energy harvesting concept for THRs. In this study, the performance of the proposed energy harvesting system was numerically and experimentally investigated. First, we numerically reproduced our previous results for the physiologically based loading situation in a simplified setup. Thereafter, this configuration was experimentally realised by the implantation of a functional model of the energy harvesting concept into an artificial bone segment. Additionally, the piezoelectric element alone was investigated to analyse the predictive power of the numerical model. We measured the generated voltage for a load profile for walking and calculated the power output. The maximum power for the directly loaded piezoelectric element and the functional model were 28.6 and 10.2 µW, respectively. Numerically, 72.7 µW was calculated. The curve progressions were qualitatively in good accordance with the numerical data. The deviations were explained by sensitivity analysis and model simplifications, e.g., material data or lower acting force levels by malalignment and differences between virtual and experimental implantation. The findings verify the feasibility of the proposed energy harvesting concept and form the basis for design optimisations with increased power output.

Prognostic factors of total hip replacement during a 2-year period in participants enrolled in supervised education and exercise therapy: a prognostic study of 3657 participants with hip osteoarthritis

Background

Evidence on prognostic factors associated with progression to total hip replacement (THR) in hip osteoarthritis (OA) is for the most patient- and disease-specific characteristics either conflicting or inconclusive. Therefore, the objectives of this study of participants with hip OA enrolled in a structured program of supervised education and exercise therapy were to describe the rate of THR and to identify prognostic factors for receiving THR within the following 2 years.

Methods

Participants aged ≥ 45 years with hip OA enrolled in Good Life with osteoArthritis in Denmark (GLA:D®) from July 2014 to March 2017 were included. Potential prognostic factors included demographic and disease-specific baseline characteristics and measures of physical activity and quality of life (QoL). Information on THR was retrieved from The Danish National Patient Registry. A multivariable Cox proportional hazards model was developed.

Results

Of 3657 included participants, 30% received a THR within 2 years. Of the 100 participants already wait-listed for THR, 60% had the procedure. Of 22 candidate prognostic factors, 14 were statistically significant for receiving THR. Factors associated with a faster rate of THR included being “male” (HR 1.43), having “self-reported radiographic hip OA” (HR 2.32), being “wait-listed for THR” (HR 2.17), and having a higher “pain intensity” (HR 1.01). In contrast, faster “walking speed” (HR 0.64), better “hip-related QoL” (HR 0.98), and having “three or more comorbidities” (HR 0.62) were predictive of a slower rate of THR.

Conclusion

During the 2-year follow-up period, 30% of the cohort received a THR. Notably, 40% of those wait-listed for THR when entering the program did not receive THR within 2 years. A number of baseline prognostic factors for receiving THR were identified.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02608-6.

Total hip revision with custom-made spacer and prosthesis: A case report

BACKGROUND

Both periprosthetic joint infections (PJIs) and severe femoral segmental defects are catastrophic complications of total hip arthroplasty (THA), and both present a significant challenge in revisional surgery. There are limited data available to guide clinical decision making when both occur concurrently.

CASE SUMMARY

A 61-year-old woman presented with a 6-mo history of a sinus tract at the site of her original THA incision. Radiological imaging revealed a total hip joint implant with an ipsilateral segmental femoral defect. Based on histological, radiological, laboratory, and clinical features, a diagnosis of concurrent chronic PJI and segmental femoral defect (Type IIIB, Paprosky classification) was made. After multidisciplinary team discussion, three-dimensional (3D)-printed, custom-made antibiotic spacers were created that could be used to mold antibiotic-loaded cement spacer. These were placed following PJI debridement in the first stage of revision surgery. After the PJI was eliminated, a 3D-printed, custom-made, femoral prosthesis was created to repair the considerable femoral defect. After 20-mo follow-up, the patient had excellent functional outcomes with a near-normal range of hip movement. So far, neither evidence of recurrent infection nor loosening of the prosthesis has been observed.

CONCLUSION

We describe a case of “two-stage, custom-made” total hip revision to treat PJI with a concurrent segmental femoral defect. Use of a personalized, 3D-printed spacer and proximal femoral prosthesis led to satisfactory hip function and no early postoperative complications. Use of a customized implant provides surgeons with an alternative option for patients where no suitable spacer or implant is available. However, the long-term function, longevity, and cost-effectiveness of the use of custom-made prostheses have yet to be fully explored.

Iodine Immobilized Metal-Organic Framework for NIR-Triggered Antibacterial Therapy on Orthopedic Implants

Iodine has been known as an effective disinfectant with broad-spectrum antimicrobial potency yet without drug resistance risk when used in clinic. However, the exploration of iodine for antibacterial therapy in orthopedics remains sparse due to its volatile nature and poor solubility. Herein, leveraging the superior absorption capability of metal-organic frameworks (MOFs) and their inherent photocatalytic properties, iodine-loaded MOF surface is presented to realize responsive iodine release along with intracellular reactive oxygen species(ROS) oxidation under near-infrared (NIR) exposure to achieve synergistic antibacterial effect. Iodine is successfully loaded using vapor deposition process onto zeolitic imidazolate framework-8(ZIF-8), which is immobilized onto micro arc oxidized titanium via a hydrothermal approach. The combination of NIR-triggered iodine release and ZIF-8 mediated ROS oxidative stress substantially augments the antibacterial efficacy of this approach both in vitro and in vivo. Furthermore, this composite coating also supported osteogenic differentiation of bone marrow stromal cells, as well as improved osseointegration of coated implants using an intramedullary rat model, suggesting improvement of antibacterial efficacy does not impair osteogenic potential of the implants. Altogether, immobilization of iodine via MOF on orthopedic implants with synergistic antibacterial effect can be a promising strategy to combat bacterial infections.

Cobalt ions induce metabolic stress in synovial fibroblasts and secretion of cytokines/chemokines that may be diagnostic markers for adverse local tissue reactions to hip implants

Adverse local tissue reactions (ALTRs) are a prominent cause of hip implant failure. ALTRs are characterized by aseptic necrosis and leukocyte infiltration of synovial tissue. The prevalence of ALTRs in hips with failing metal implants, with highest rates occurring in patients with metal-on-metal articulations, suggests a role for CoCrMo corrosion in ALTR formation. Although hypersensitivity reactions are the most accepted etiology, the precise cellular mechanism driving ALTR pathogenesis remains enigmatic. Here we show that cobalt ions released by failing hip implants induce mitochondrial stress and cytokine secretion by synovial fibroblasts: the presumptive initiators of ALTR pathogenesis. We found that in-vitro treatment of synovial fibroblasts with cobalt, but not chromium, generated gene expression changes indicative of hypoxia and mitophagy responses also observed in ALTRs biopsies. Inflammatory factors secreted by cobalt-exposed synovial fibroblasts were among those most concentrated in ALTR synovial fluid. Furthermore, both conditioned media from cobalt-exposed synovial fibroblasts, and synovial fluid from ALTRs patients, elicit endothelial activation and monocyte migration. Finally, we identify the IL16/CTACK ratio in synovial fluid as a possible diagnostic marker of ALTRs. Our results provide evidence suggesting that metal ions induce cell stress in synovial fibroblasts that promote an inflammatory response consistent with initiating ALTR formation. STATEMENT OF SIGNIFICANCE: We demonstrate that the cytotoxic effects of cobalt ions on the synovial cells (fibroblast) is sufficient to trigger inflammation on hip joints with metal implants. Cobalt ions affect mitochondrial function, leading to the auto phagocytosis of mitochondria and trigger a hypoxic response. The cell's hypoxic response includes secretion of cytokines that are capable of trigger inflammation by activating blood vessels and enhancing leukocyte migration. Among the secreted cytokines is IL-16, which is highly concentrated in the synovial fluid of the patients with adverse local tissue reactions and could be use as diagnostic marker. In conclusion we define the cells of the hip joint as key players in triggering the adverse reactions to hip implants and providing biomarkers for early diagnosis of adverse reactions to hip implants.

The Patient-Specific Combined Target Zone for Morpho-Functional Planning of Total Hip Arthroplasty

Background Relevant criteria for total hip arthroplasty (THA) planning have been introduced in the literature which include the hip range of motion, bony coverage, anterior cup overhang, leg length discrepancy, edge loading risk, and wear. The optimal implant design and alignment depends on the patient’s anatomy and patient-specific functional parameters such as the pelvic tilt. The approaches proposed in literature often consider one or more criteria for THA planning. but to the best of our knowledge none of them follow an integrated approach including all criteria for the definition of a patient-specific combined target zone (PSCTZ). Questions/purposes (1) How can we calculate suitable THA implant and implantation parameters for a specific patient considering all relevant criteria? (2) Are the resulting target zones in the range of conventional safe zones? (3) Do patients who fulfil these combined criteria have a better outcome score? Methods A method is presented that calculates individual target zones based on the morphology, range of motion and load acting on the hip joint and merges them into the PSCTZ. In a retrospective analysis of 198 THA patients, it was calculated whether the patients were inside or outside the Lewinnek safe zone, Dorr combined anteversion range and PSCTZ. The postoperative Harris Hip Scores (HHS) between insiders and outsiders were compared. Results 11 patients were inside the PSCTZ. Patients inside and outside the PSCTZ showed no significant difference in the HHS. However, a significant higher HHS was observed for the insiders of two of the three sub-target zones incorporated in the PSCTZ. By combining the sub-target zones in the PSCTZ, all PSCTZ insiders except one had an HHS higher than 90. Conclusions The results might suggest that, for a prosthesis implanted in the PSCTZ a low outcome score of the patient is less likely than using the conventional safe zones by Lewinnek and Dorr. For future studies, a larger cohort of patients inside the PSCTZ is needed which can only be achieved if the cases are planned prospectively with the method introduced in this paper. Clinical Relevance The method presented in this paper could help the surgeon combining multiple different criteria during THA planning and find the suitable implant design and alignment for a specific patient.

Causes, risk factors, and costs associated with ninety-day readmissions following primary total hip arthroplasty for femoral neck fractures

INTRODUCTION

Risk factors associated with primary THA readmissions have not yet been thoroughly analyzed when stratified by underlying indication. Given that a majority of THAs are done electively in the context of osteoarthritis (OA), it remains to be explored whether or not THAs performed non-electively in the trauma setting have different readmission patterns. Therefore, the aims of this study were to identify: 1) causes of readmissions; 2) patient-related risk-factors for readmissions; and 3) costs associated with the reasons for readmissions.

MATERIALS AND METHODS

Patients who sustained a femoral neck fracture and underwent primary THA from 2005 to 2014 were identified. Those subsequently readmitted within 90-days following the procedure comprised the study cohort whereas those not readmitted served as the comparison cohort. Primary outcomes included identifying causes of readmissions, identifying patient-related risk-factors associated with readmissions and determining healthcare expenditures associated with the different readmission etiologies. A regression analysis was used to calculate the odds (OR) for readmissions. A p-value less than 0.01 was considered to be statistically significant.

RESULTS

The regression model demonstrated the greatest patient-related risk factors included: electrolyte and fluid disorders (OR: 1.80, p < 0.0001), morbid obesity (OR: 1.60, p < 0.0001), pathologic weight loss (OR: 1.58, p < 0.0001), congestive heart failure (OR: 1.41, p < 0.0001), were the leading risk factors for readmissions. Pulmonary-related causes ($42,357.71) of readmission were the leading driver of costs of care.

CONCLUSION

Orthopaedic surgeons should identify and optimize pre-operative management of patient-related risk factors that increase readmissions following primary THA for femoral neck fractures. Additionally, pulmonary-related causes of readmission lead to the highest costs of care.

LEVEL OF EVIDENCE

III.

Cross-sectional Analysis of Recommendations for the Treatment of Hip and Knee Osteoarthritis in Clinical Guidelines

OBJECTIVE

To compare guideline recommendations for hip and knee osteoarthritis (OA) and their level of evidence.

DATA SOURCES

MEDLINE, Embase, the Cochrane Library, and websites of professional societies were searched in June 2020 using keywords such as knee or hip osteoarthritis, degenerative arthritis, guideline, and practice guideline.

STUDY SELECTION

General treatment guidelines for OA of the hip or knee published in English. After 461 abstracts were screened, 31 publications (17 guidelines from 10 professional societies) were included for analysis.

DATA EXTRACTION

Three reviewers assessed the quality of the guidelines according to the Appraisal of Guidelines for Research and Evaluation II tool. The rating of evidence and strength of recommendation was extracted and standardized into the Grading of Recommendations Assessment, Development, and Evaluation criteria.

DATA SYNTHESIS

Of the 17 guidelines included, 6 (35%) were of high quality, 10 (59%) of moderate quality, and 1 (6%) of low quality. Guidelines published after 2017 were of good quality. Although guidelines generally agreed on a nonsurgical multimodal concept, including patient education, exercise, and weight loss in obese, some recommendations remained vague and the level of evidence varied widely. In pharmacologic treatment, oral nonsteroidal anti-inflammatory drugs were the mainstay for pain management. Guidelines published after 2017 were more cautious in their recommendation for the use of paracetamol and strong opioids. Disagreement was observed for chondroitin sulfate, glucosamine, and intra-articular hyaluronic acid injections. Recommendations were conflicting for the use of insoles, braces, and transcutaneous electrical stimulation. The main indications for hip/knee arthroplasty were severe, persisting pain and loss of function despite nonsurgical treatment. No guideline defined a minimum time of conservative treatment before surgery.

CONCLUSIONS

We found a wide variation in evidence and strength of recommendations for OA treatment. Recommendations on when to refer patients for surgery remained unclear.

Return to Competitive Level of Play and Performance in Regular Golfers After Total Hip Arthroplasty: Analysis of 599 Patients at Minimum 2-Year Follow-Up

BACKGROUND

Total hip arthroplasty (THA) is performed in an increasingly younger and athletic population. Regular and competitive golfers are concerned with the likelihood of recovering their preoperative level of play. The purpose of this study was to assess the impact of primary THA on golfers' game, with a minimum follow-up of two years.

METHODS

Questionnaires were sent to the French Golf Federation's golfing members. Those who were older than 40 years and had undergone a unilateral primary THA provided information on the timing of return to play, pain during golfing, transportation mode, drive length, handicap and weekly playtime, before hip replacement, and postoperatively. In addition, data relating to the surgical procedure were collected.

RESULTS

Surveys were completed by 883 competitive golfers of which 599 were eligible for inclusion. The mean time to return to a complete 18-hole course was 4.73 months (SD 4.15, range: 0.7-36). Participants surveyed at a minimum 2 years after THA played at a higher level than before surgery with a handicap improvement of 1.8 (P < .01) and increased their mean weekly playtime from 8.8 to 9.3 hours (P = .24, NS). Eighty-eight percent reported an increased or no change in drive distance. Hip pain while playing golf decreased after surgery (6.8 to 2.5 on the visual analog scale, P < .001).

CONCLUSION

This study highlighted that hip arthroplasty allowed regular and competitive golfers to return to the course with better golfing comfort than before surgery and with an objective improvement in driving distance and level of play.

High prevalence and undertreatment of osteoporosis in elderly patients undergoing total hip arthroplasty

We detected a high prevalence of low bone mineral density assessed by DXA in 268 elderly patients with end-stage osteoarthritis scheduled for total hip arthroplasty (18% osteoporosis, 41% osteopenia). Therefore, and due to the identified concomitant undertreatment, routine DXA measurements should be considered in elderly patients prior to surgery.

INTRODUCTION

Bone quality represents a decisive factor for osseointegration, durability, and complications of an implanted prosthesis. Although the risk of osteoporosis increases with age and the assessment of bone mineral density (BMD) prior to total hip arthroplasty (THA) is recommended in elderly patients, a systematic, unbiased analysis of such patients is not available in the literature.

METHODS

In this retrospective study, we examined 268 elderly patients (age ≥70 years) who underwent dual-energy X-ray absorptiometry (DXA) within 3 months prior to primary THA. Demographics, medical history, radiographic OA grade, and stem fixation method (i.e., cemented or cementless) were obtained.

RESULTS

In total, 153 (57%) cemented and 115 (43%) cementless stem fixations during THA were performed. Forty-nine patients (18%) were diagnosed with osteoporosis (T-score ≤-2.5), 110 patients (41%) with osteopenia (T-score ≤-1.0), and 109 patients (41%) with normal BMD (T-score >-1.0). Importantly, 36/49 patients (73%) with osteoporosis were not diagnosed before, resulting in a relevant undertreatment. Female sex and low body mass index (BMI) were the main factors negatively influencing the bone mineral density (BMD).

CONCLUSIONS

Due to a high incidence of undiagnosed and untreated osteoporosis in elderly patients with potential effects on the success of osseointegration as well as other clinical outcomes, DXA measurements should be included in the clinical routine for these patients prior to THA.

The effect of fascia iliaca block on postoperative pain and analgesic consumption for patients undergoing primary total hip arthroplasty: a meta-analysis of randomized controlled trials

Background

The primary aim of this systematic review and meta-analysis was to compare postoperative pain, analgesic consumption, and complications after fascia iliaca block (FIB) versus control for patients undergoing primary total hip arthroplasty (THA). Second, we compared the outcomes of FIB versus placebo. Finally, we sought to evaluate pain and analgesic consumption after preoperative and postoperative FIB.

Methods

We performed a systematic literature search in MEDLINE, Embase, Scopus, Web of Science, Google Scholar, ClinicalTrials.gov, and CENTRAL through February 2021 to identify randomized controlled trials (RCTs) that evaluated the efficacy of FIB versus control for patients undergoing primary THA. All analyses were conducted on intent-to-treat data with a random-effects model.

Results

Twelve RCTs with a total of 815 patients were included. There was no difference in postoperative pain (P = 0.64), analgesic consumption (P = 0.14), or complication rate (P = 0.99) between FIB and control groups. Moreover, no difference in postoperative pain (P = 0.26), analgesic consumption (P = 0.06), or complication rate (P = 0.71) was found between FIB and placebo. Moreover, sensitivity analysis suggested that no significant difference in postoperative pain, analgesic consumption, or complication rate was present between FIB and control in studies that used preoperative and postoperative FIB.

Conclusion

FIB was not found to be superior to placebo or various anesthetic techniques for patients undergoing primary THA, as measured by postoperative pain, analgesic consumption, and complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02585-1.

Diagnostic Performance of Dual-Energy CT for Detecting Painful Hip Prosthesis Loosening

Background Revisions of hip prostheses are increasing, and conventional radiography (CR) is a primary tool for managing -complications. However, dual-energy CT (DECT) with virtual monoenergetic imaging is capable of reducing periprosthetic metal artifacts compared with standard CT. Purpose To compare the diagnostic performance of DECT and CR in detecting hip prosthesis loosening, using surgery as a reference for diagnosis. Materials and Methods This retrospective single-center study conducted between January 2018 and October 2020 included -consecutive patients with unilateral painful hip prostheses. Two independent readers (with 15 years and 4 years of experience) who were blinded to clinical findings evaluated CR and DECT images. At imaging, diagnosis of loosening prosthesis was made for -periprosthetic radiolucency greater than or equal to 2 mm wide or the presence of two or more secondary findings, including -periprosthetic osteolysis, angulation of the implant, fracture, or abnormal periosteal reaction. For each reader and for each imaging parameter, -sensitivity and specificity were calculated. The diagnostic performance of each imaging tool was compared by using the McNemar test. Interobserver agreements were calculated with Cohen κ statistics. Statistical software was used. Results Overall, 178 patients (mean age ± standard deviation, 74 years ± 20; 96 men) were included (121 undergoing surgery, 57 follow-up). Overall, 87 of 178 patients (49%) were diagnosed with a loosened prosthesis. DECT had higher sensitivity and specificity than CR for both reader 1 (94% [82 of 87 examinations; 95% CI: 87, 98] and 93% [85 of 91 examinations; 95% CI: 86, 97] vs 84% [73 of 87 examinations; 95% CI: 74, 91] and 91% [83 of 91 examinations; 95% CI: 83, 96], respectively; P < .001) and reader 2 (92% [80 of 87 examinations; 95% CI: 84, 97] and 95% [86 of 91 examinations; 95% CI: 88, 98] vs 80% [70 of 87 -examinations; 95% CI: 71, 88] and 91% [83 of 91 examinations; 95% CI: 83, 96], respectively; P = .001), with better interobserver agreement (κ, 0.88 [95% CI: 0.81, 0.95] vs 0.78 [95% CI: 0.69, 0.88]). Conclusion Dual-energy CT showed better diagnostic performance than conventional radiography in diagnosing hip prosthesis loosening. See also the editorial by Lutz in this issue. © RSNA, 2021.

The Hip-Spine Relationship in Total Hip Arthroplasty: How to Execute the Plan

BACKGROUND

Patients with spinopelvic pathology, including lumbar spine stiffness and sagittal spinal deformity, are at increased risk for postoperative complications, including instability, dislocation, and revision after total hip arthroplasty (THA). Recent evidence has suggested that the Lewinnek safe zone should no longer be considered an appropriate target for all patients, especially those with spinopelvic pathology, as the safe zone is a dynamic rather than static target. There are 2 distinct issues for arthroplasty surgeons to consider: lumbar spinal stiffness and sagittal spinal deformity, each of which has its own management.

METHODS

In order to manage patients with spinopelvic pathology undergoing THA, a basic understanding of spinopelvic parameters, including sagittal balance, sacral slope, and anterior pelvic plane, is essential. Techniques outlined in this manuscript describe a systematic preoperative work-up and intraoperative management of acetabular component positioning according to patient-specific spinopelvic parameters, ensuring optimal component placement and a reduced risk for impingement, instability, and poor postoperative outcomes.

RESULTS

Evaluation of each patient's spinopelvic parameters informs patient classification according to the Hip-Spine Classification for THA. Patient classification is determined by the presence of spinal stiffness and spinal deformity, with corresponding scoring and classification into one of the 4 categories used to determine risk for postoperative dislocation, define patient-specific cup positioning, and create their functional safe zone.

CONCLUSION

A simple 2-step preoperative assessment with measurements of the anterior pelvic plane and the sacral slope on standing and seated lateral X-rays will identify patients at high risk for postoperative dislocation due to spinal deformity and/or stiffness. Accounting for spinopelvic pathology and adhering to the Hip-Spine Classification guidelines for acetabular component positioning can help reduce the burden of instability and revisions in this complex patient population.

Clinical considerations for reposition of a dislocated hip: A qualitative study

BACKGROUND

A well-known complication of having hip alloplasty surgery is dislocation of the prothesis. This affects 2%-4% of the patients, and 75% of the dislocations occur within the first year after surgery. The aim of our study was to gain knowledge about the clinical considerations underlying the choice of anaesthesia for, and treatment of, patients with dislocated hips by specialists in anaesthesiology and orthopaedic surgery.

METHODS

We used semi-structured group interviews of specialists in anaesthesiology and orthopaedic surgery. An interview guide was developed and pilot tested before the group interviews. In total, 25 specialists participated, recruited from two university hospitals in Denmark. Data saturation was reached after seven group interviews. Inductive content analysis was used in the data analysis.

RESULTS

We identified four overall themes, describing essential considerations made by the specialists: "Adhering to the principle of minimal intervention", "Ensuring patient safety through optimal working conditions", "Organisational considerations" and "Pain induced gastric retention".

CONCLUSION

Our study illustrates different clinical considerations made by specialists in anaesthesiology and orthopaedic surgery in relation to the treatment of patients with dislocated hips. Our results hope to promote mutual understanding in joint clinical decision-making in relation to patients with dislocated hips as well as to inspire less-experienced anaesthesiologists and orthopaedic surgeons. Additionally, our results suggest a set of "rules of thumb" for how jointly to decide on the repositioning site of the patient during the procedure.

Total Ankle Arthroplasty With Valgus Deformity

BACKGROUND

A substantial coronal plane deformity is common in the context of end-stage ankle osteoarthritis. Recent literature shows a trend toward extending the indication of total ankle arthroplasty in increasingly severe coronal deformities, showing promising results when correct alignment is achieved. Nevertheless, the results of lateral transfibular total ankle replacement (LTTAR) in valgus has not been extensively studied. We aimed to evaluate if the outcomes of LTTAR in ankles with valgus deformity were similar to those with no major deformity at short-term follow-up.

METHODS

This retrospective cohort study included 228 LTTARs. Patients were classified into 2 groups according to the preoperative coronal plane tibiotalar angle (TTS): neutral (less than 10 degrees of coronal deformity, 209 patients) and valgus (above 10 degrees of valgus, 19 patients). Clinical evaluation was performed using the American Orthopaedic Foot & Ankle Society (AOFAS) score, visual analog scale (VAS), 12-Item Short Form Health Survey 12 (SF-12) regarding its Physical and Mental Component Summary items. The radiographic evaluation considered anteroposterior and lateral ankle radiographs. Complications were also registered and classified as major or minor. The minimum follow-up was 2 years.

RESULTS

The average AOFAS, VAS, and SF-12 scores improved significantly postoperatively (P < .001), without differences between groups. At final radiographic follow-up, the valgus alignment group did not show significant differences with the neutral alignment group regarding TTS, lateral distal tibial angle, or anterior distal tibial angle (P > .05).

CONCLUSION

LTTAR in cases with valgus deformity achieved and maintained correction at short-term follow-up, as obtained in neutral alignment ankles. Clinical outcomes improved significantly regardless of preoperative valgus deformity.

LEVEL OF EVIDENCE

Prognostic Level III, retrospective cohort study.

The association between psychological factors and pain exacerbations in hip osteoarthritis

OBJECTIVES

To evaluate the association between psychological factors and pain exacerbations in people with hip OA.

METHODS

Eligible participants with symptomatic hip OA were instructed to complete online questionnaires every 10 days over a 90-day follow-up period. In addition, they were required to complete the questionnaire whenever they perceived they were experiencing a hip pain exacerbation. Hip pain exacerbation was defined as an increase of 2 points in pain intensity compared with baseline on an 11-point numeric rating scale (0-10). The Depression, Anxiety and Stress Scale-21 Items, Positive and Negative Affect Schedule, Pain Catastrophizing Scale and Pain Self-Efficacy Questionnaire were used to evaluate psychological factors. The associations of these with risk of hip pain exacerbation were examined by conditional logistic regression.

RESULTS

Of 252 participants recruited, 131 (52.0%) contributed both case and control period data and were included in the analysis. A significant association was found between Pain Catastrophizing Scale overall score (1 point increase) with hip pain exacerbations (odds ratio: 1.07, 95% CI: 1.04, 1.11). An increase of a minimal important change (5.5 points) of Pain Self-Efficacy Questionnaire score was associated with a lower odds of pain exacerbations (odds ratio: 0.74, 95% CI: 0.65, 0.85). No significant associations were found between Depression, Anxiety and Stress Scale-21 Items or Positive and Negative Affect Schedule scores with hip pain exacerbations.

CONCLUSION

Both pain catastrophizing and pain self-efficacy beliefs were associated with pain exacerbations in people with hip OA, but other psychological factors including depression, anxiety and stress or positive and negative affects, were not associated with pain exacerbations.

Comparison of Outcomes After Robotic-Assisted or Conventional Total Hip Arthroplasty at a Minimum 2-Year Follow-up: A Systematic Review

BACKGROUND

This systematic review aimed to present an updated analysis of the evidence comparing outcomes between robotic-assisted total hip arthroplasty (robotic THA) and conventional manual total hip arthroplasty (manual THA).

METHODS

A PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) systematic review was performed using the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, PubMed, MEDLINE, and Embase. Controlled studies comparing primary robotic THA and manual THA utilizing patient-reported outcome measures (PROMs) at a minimum follow-up of 2 years were included. We also compared radiographic outcomes, dislocation rates, and revision surgical procedures between groups. The ROBINS-I (Risk of Bias in Non-Randomized Studies - of Interventions) and Cochrane Risk of Bias 2.0 tools were used to assess study quality and risk of bias.

RESULTS

Of 765 studies identified, 7 articles comparing robotic THA with manual THA met inclusion criteria. A total of 658 patients were assessed, 335 of whom underwent robotic THA. The majority of studies found no significant differences (p > 0.05) in PROMs between the 2 techniques. Two low-quality studies (Level III) found significantly better postoperative PROMs favoring robotic THA at 2 years. When assessing radiographic outcomes, 6 studies showed that robotic THA resulted in more consistent and accurate component placement. No differences in postoperative dislocations, complications, or revision rates were found between groups except in 1 study, which found significantly more dislocations and revisions in the robotic THA cohort. Reported operative times were a mean of 12 to 25 minutes longer when using robotic THA.

CONCLUSIONS

The existing literature comparing robotic THA and manual THA is scarce and low-quality, with findings limited by methodological flaws in study design. Although evidence exists to support increased accuracy and reproducibility of THA component placement with robotic THA, this has not been shown to reduce postoperative dislocation and revision rates. Based on the available evidence, functional outcomes are comparable between techniques, and robotic THA appears to be associated with longer operative times. To fully evaluate the utility of robotic THA, additional well-designed, prospective controlled studies with continuous long-term monitoring are required.

LEVEL OF EVIDENCE

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

The Influence of Geographic Region on Hip and Knee Arthroplasty Literature From 1988 to 2018

Total joint arthroplasty constitutes a major focus of publications within orthopaedics. Because research expands and investigators from around the world contribute, it is important to understand the dynamics of publication.

Drug Release from Thermo-Responsive Polymer Brush Coatings to Control Bacterial Colonization and Biofilm Growth on Titanium Implants

Despite decades of biomedical advances, the colonization of implant devices with bacterial biofilms is still a leading cause of implant failure. Clearly, new strategies and materials that suppress both initial and later stage bacterial colonization are required in this context. Ideal would be the implementation of a bactericidal functionality in the implants that is temporally and spatially triggered in an autonomous fashion at the infection site. Herein, the fabrication and validation of functional titanium-based implants with triggered antibiotic release function afforded via an intelligent polymer coating is reported. In particular, thermo-responsive poly(di(ethylene glycol) methyl ether methacrylate) (PDEGMA) brushes on titanium implants synthesized via a surface-initiated atom transfer radical polymerization with activators regenerated through the electron transfer technique (ARGET ATRP) allows for a controlled and thermally triggered release of the antibiotic levofloxacin at the wound site. Antibiotic loaded brushes are investigated as a function of thickness, loading capacity for antibiotics, and temperature. At temperatures of the infection site >37 °C the lower critical solution temperature behavior of the brushes afforded the triggered release. Hence, in addition to the known antifouling effects, the PDEGMA coating ensured enhanced bactericidal effects, as demonstrated in initial in vivo tests with rodents infected with Staphylococcus aureus.

Antibacterial application of gentamicin-silk protein coating with smart release function on titanium, polyethylene, and Al2O3 materials

Peri-implant infection after hip and knee arthroplasty is a common and serious complication. Titanium (Ti), polyethylene (PE), and Al₂O₃ materials used as joint prosthesis materials have good biocompatibility and mechanical strength but no antibacterial effect. This study aimed to provide a theoretical basis for the design and manufacture of joint prosthesis materials with antibacterial effect. We applied a coating of gentamicin-silk protein (GS-Silk) on the surface of these materials. We characterized the Ti, PE, and Al₂O₃ materials coated with GS-Silk (experimental group) and performed in vivo and in vitro experiments to test antibacterial activity. Scanning electron microscopy confirmed successful GS-Silk coating, and infrared spectroscopy confirmed successful loading of gentamicin onto the three materials. Nanoscratch test proved that the GS-Silk coating is relatively reliable on the surface of these three materials. The antibacterial effect of the coating in vitro and in vivo was verified by performing bacteriostatic ring test in vitro, bacterial adhesion test, and subendothelial implant infection test. We demonstrated that GS-Silk coating can effectively load gentamicin onto Ti, PE, and Al₂O₃ materials and change the gentamicin release rate with a change in the solution pH to achieve intelligent release. The GS-Silk coating is relatively reliable on the surface of these three materials. Ti, PE, and Al₂O₃ materials coated with GS-Silk have good antibacterial ability, both in vivo and in vitro.

Systematic review of primary total hip arthroplasty using titanium-titanium modular-neck prostheses: the true risk of revision

AIMS

Modular-neck femoral implants are used to enable more variability in femoral neck version, offset and length. It has been reported that these implants carry a higher rate of revision. The aim of this review was to assess the overall and cause-specific revision rate of titanium-titanium alloy modular-neck implants in primary total hip arthroplasty (THA).

METHODS

A systematic review was conducted following PRISMA guidelines and utilising multiple databases. All results were screened for eligibility. Studies published from 2000 onwards, using a current-generation, titanium-titanium, modular-neck implant were included. Overall and cause-specific revision rates were analysed, comparing to fixed-neck prostheses where applicable.

RESULTS

920 studies were screened. After applying exclusion criteria, 23 were assessed in full and 14 included. These consisted of 12 case series and 2 joint registry analyses. 21,841 patients underwent a modular-neck implant with a weighted mean follow-up of 5.7 years, mean age of 62.4 years, and average body mass index (BMI) of 28.4kg/m². The overall revision rate was 3.95% and 2.98% for modular and fixed-neck prostheses, respectively. For studies with >5 years follow-up the mean revision rate was 3.08%. There was no difference in cause-specific revision rates by implant design. Mean improvement in Harris Hip Score was 41.9.

CONCLUSIONS

At medium-term, revision rates for titanium-titanium primary modular-neck THA are acceptable. These prostheses are a sensible management option in patients with considerable anatomical hip deformity not amenable to correction with standard fixed-neck implants. Patients of male gender, high BMI and requiring prostheses with a larger neck, offset or head are at higher risk of implant failure.

The influence of bariatric surgery on hip and knee joint pain: a systematic review

Obesity increases the risk of osteoarthritis and the chance of needing joint replacement arthroplasty to reduce lower limb joint pain. Although nonsurgical weight loss interventions can reduce hip and knee joint pain, bariatric surgery may be a more feasible treatment option for people with severe obesity. However, it is unclear whether weight loss through bariatric surgery can positively influence hip and knee joint pain. Our objective was to evaluate the influence of bariatric surgery on hip and knee joint pain in people with obesity by conducting a systematic review of the literature. The PubMed, EMBASE, and Cochrane bibliographic databases were searched for studies published between 1947 and September 2019. Risk of bias of the identified studies was independently assessed by 2 reviewers using JBI's Critical Appraisal Checklist for Case Series and the Newcastle-Ottawa Scale. This review included 23 studies, all of which evaluated knee pain and 9 of which also evaluated hip pain. Reported results regarding hip pain intensity and the proportion of participants with hip pain were too limited to draw useful conclusions. Reported results regarding knee pain suggest that weight loss after bariatric surgery reduced knee pain intensity, as well as the proportion of participants with knee pain. The overall risk of bias of the majority of included studies (83%; n = 19) was judged to be unclear to high. Four small studies were judged as having a low risk of bias. Results of this systematic review suggest that bariatric surgery can positively influence hip and knee joint pain, but conclusive evidence is lacking because most of the included studies were judged as having plausible bias overall and in their key domains. Well-designed randomized controlled trials evaluating the influence of bariatric surgery on hip and knee joint pain using standardized joint pain measures are needed.

Is convention hip precaution necessary after total hip arthroplasty?

Background:

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

Methods:

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

Results:

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

Conclusion:

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

[Decision for total hip arthroplasty-the surgeons' view]

BACKGROUND

The decision for total hip arthroplasty (THA) is based on pain, loss of function, radiological changes and failed conservative therapy. These criteria are rarely based on systematic research and have not been integrated in generally accepted treatment guidelines. Aim of our study was, therefore, to analyse which decision criteria German orthopaedic and trauma surgeons use in order to recommend THA for patients with hip osteoarthritis.

MATERIALS AND METHODS

From 10/2019 to 07/2020 we conducted a nation-wide survey among 218 orthopaedic and trauma surgeons about their criteria for and against THA surgery, as well as their treatment objectives.

RESULTS

147 fully completed questionnaires were analysed. Pain (99%), limitation of movement (99%), as well as impairment of walking distance (97%), and the subjective burden (97%) were the most frequent criteria. 97% and 96% of surgeons consider prescription of analgesics and physical therapy, as well as a lack of their effectiveness, as criteria for THA. 87% see radiological changes grade Kellgren & Lawrence III as threshold. A recommendation against surgery is triggered by obesity (BMI ≥ 40 kg/m²) in 48% and by the presence of an active infection in 96%.

CONCLUSIONS

Current surgeons' practice criteria of recommendations for THA in Germany seem to reflect widely nationally and internationally discussed recommendations. Particular attention is given to patient factors like pain, loss of function and subjective burden, as well as previous conservative treatment and contraindications, like poorly controlled diabetes or an active infection, whereas morbid obesity is not seen as contraindication by all surgeons.

Three-dimensional analysis of the cortical contact state of short and conventional stems in different stem positions in total hip arthroplasty

BACKGROUND

Despite the increasing use of short cementless stems in total hip arthroplasty, their potential benefits have yet to be confirmed. We evaluated the cortical contact state of short and conventional stems in different femoral canal types and stem positions using a CT-based 3-dimensional templating software.

METHODS

We reviewed 153 hips in 153 patients, grouped according to femoral canal type-normal (68), champagne-flute (41), and stove-pipe canal (44). We investigated the influence of stem position on the contact state by evaluating three situations of stem anteversion (original anteversion, +5°anteverted, and +5°retroverted), three stem positions, neutral +2°extended, and +2°flexed positions using Taperloc Complete Microplasty^Ⓡ stem.

FINDINGS

The contact values of all zones between both stems in all canal types exhibited no significant differences. The values in zones 1, 2, 6, and 7 of both stems in 5° retroverted and anteverted, 2° extended and flexed positions were not significantly different compared to those of the neutral position. However, the values in zones 3, 4, and 5 of both stems were significantly greater compared to those of the neutral position in 2° extended and flexed positions; these values were also significantly larger in all canal types for the conventional stem.

INTERPRETATION

We demonstrated that the short and conventional stems can achieve the same proximal cortical contact in any femoral canal, regardless of the stem position. However, extended and flexed stem positions increase the distal contact, especially in conventional stems. Furthermore, the distal contact increases for the retroverted stem insertions.

An alternative ex vivo method to evaluate the osseointegration of Ti-6Al-4V alloy also combined with collagen

Due to the increasing number of orthopedic implantation surgery and advancements in biomaterial manufacturing, chemistry and topography, there is an increasing need of reliable and rapid methods for the preclinical investigation of osseointegration and bone ingrowth. Implant surface composition and topography increase osteogenicity, osteoinductivity, osteoconductivity and osseointegration of a prosthesis. Among the biomaterials used to manufacture an orthopedic prosthesis, titanium alloy (Ti-6Al-4V) is the most used. Type I collagen (COLL I) induces cell function, adhesion, differentiation and bone extracellular matrix component secretion and it is reported to improve osseointegration if immobilized on the alloy surface. The aim of the present study was to evaluate the feasibility of an alternative ex vivo model, developed by culturing rabbit cortical bone segments with Ti-6Al-4V alloy cylinders (Ti-POR), fabricated through the process of electron beam melting (EBM), to evaluate osseointegration. In addition, a comparison was made with Ti-POR coated with COLL I (Ti-POR-COLL) to evaluate osseointegration in terms of bone-to-implant contact (BIC) and new bone formation (nBAr/TAr) at 30, 60 and 90 d of culture. After 30 and 60 d of culture, BIC and nBAr/TAr resulted significantly higher in Ti-POR-COLL implants than in Ti-POR. No differences have been found at 90 d of culture. With the developed model it was possible to distinguish the biomaterial properties and behavior. This study defined and confirmed for the first time the validity of the alternative ex vivo method to evaluate osseointegration and that COLL I improves osseointegration and bone growth of Ti-6Al-4V fabricated through EBM.

Towards an effective sensing technology to monitor micro-scale interface loosening of bioelectronic implants

Instrumented implants are being developed with a radically innovative design to significantly reduce revision surgeries. Although bone replacements are among the most prevalent surgeries performed worldwide, implant failure rate usually surpasses 10%. High sophisticated multifunctional bioelectronic implants are being researched to incorporate cosurface capacitive architectures with ability to deliver personalized electric stimuli to peri-implant target tissues. However, the ability of these architectures to detect bone-implant interface states has never been explored. Moreover, although more than forty technologies were already proposed to detect implant loosening, none is able to ensure effective monitoring of the bone-implant debonding, mainly during the early stages of loosening. This work shows, for the first time, that cosurface capacitive sensors are a promising technology to provide an effective monitoring of bone-implant interfaces during the daily living of patients. Indeed, in vitro experimental tests and simulation with computational models highlight that both striped and circular capacitive architectures are able to detect micro-scale and macro-scale interface bonding, debonding or loosening, mainly when bonding is weakening or loosening is occurring. The proposed cosurface technologies hold potential to implement highly effective and personalized sensing systems such that the performance of multifunctional bioelectronic implants can be strongly improved. Findings were reported open a new research line on sensing technologies for bioelectronic implants, which may conduct to great impacts in the coming years.

TiO2 bioactive implant surfaces doped with specific amount of Sr modulate mineralization

One of the main problems that remain in the implant industry is poor osseointegration due to bioinertness of implants. In order to promote bioactivity, calcium (Ca), phosphorus (P) and strontium (Sr) were incorporated into a TiO₂ porous layer produced by micro-arc oxidation. Ca and P as bioactive elements are already well reported in the literature, however, the knowledge of the effect of Sr is still limited. In the present work, the effect of various amounts of Sr was evaluated and the morphology, chemical composition and crystal structure of the oxide layer were investigated. Furthermore, in vitro studies were carried out using human osteoblast-like cells. The oxide layer formed showed a triplex structure, where higher incorporation of Sr increased Ca/P ratio, amount of rutile and promoted the formation of SrTiO₃ compound. Biological tests revealed that lower concentrations of Sr did not compromise initial cell adhesion neither viability and interestingly improved mineralization. However, higher concentration of Sr (and consequent higher amount of rutile) showed to induce collagen secretion but with compromised mineralization, possibly due to a delayed mineralization process or induced precipitation of deficient hydroxyapatite. Ca-P-TiO₂ porous layer with less concentration of Sr seems to be an ideal candidate for bone implants.

Calcified cartilage in patients with osteoarthritis of the hip compared to that of healthy subjects. A design-based histological study

OBJECTIVE

Calcified cartilage is suggested to be involved in the pathogenesis of osteoarthritis (OA) by facilitating endochondral ossification at the bone-cartilage unit. Therefore, the objective was to quantify the volume and surface area of the calcified cartilage in the femoral head in OA patients and healthy subjects.

MATERIALS AND METHODS

We used design-based stereological principles, i.e., systematic uniform random sampling and vertical uniform random sections of the entire femoral head. We investigated the articular and calcified cartilage and femoral head surface area and volume, excluding fovea capitis and marginal osteophytes, in 20 patients with OA and 15 healthy subjects.

RESULTS

The volume of the calcified cartilage was significantly larger for the patients with OA compared with the healthy subjects (mean difference [95% CI]) (284 [110,457] mm³, p = 0.002). The upper and lower surface area of the calcified cartilage, i.e. the tidemark and cement line, were both significantly larger for OA patients compared with the healthy subjects (17.8 [8.4,27.3] cm², p < 0.001) and (38.7 [20.8,56.7] cm², p = 0.002), respectively. The volume of the calcified cartilage and the volume of the femoral head were significantly correlated for the patients with OA (Spearman's ρ = 0.51, p = 0.021), but not for the healthy subjects (ρ = 0.41, p = 0.123).

CONCLUSIONS

Patients with OA had a larger femoral head surface area and more calcified cartilage compared to healthy subjects. The volume of the calcified cartilage correlated positively with the volume of the femoral head for patients with OA, but not for healthy subjects. This strongly supports the existing view that bone growth in OA is associated with endochondral ossification.

Risk factors of postoperative delirium in the knee and hip replacement patients: a systematic review and meta-analysis

BACKGROUND

The risk factors of postoperative delirium (POD), a serious while preventable complication, developed by patients undergoing knee and replacement surgery are still under investigation. In this systematic review and meta-analysis, we identified risk factors associated with POD in knee and hip replacement.

METHODS

PubMed, Ovid MEDLINE, and Ovid EMBASE were used to identify original researches. The studies evaluating the risk factors of POD after knee and hip replacement were reviewed, and the qualities of the included studies were assessed with Newcastle-Ottawa Scale. Data were extracted, pooled, and a meta-analysis was completed RESULT: Twenty-two studies were finally included with a total of 11934 patients who underwent knee or hip replacement and 1841 developed POD with an incidence of 17.6% (95% confidential interval (CI) 13.2-22.0%). Eighteen significant risk factors were identified including advanced age (odds ratio (OR) 1.15 95% CI 1.08-1.22), cognitive impairment (OR 6.84, 95% CI 3.27-14.33), history of cerebrovascular events (OR 2.51, 95% CI 1.28-4.91), knee replacement (OR 1.42, 95% CI 1.00-2.02), blood loss (standardized mean difference (SMD) 0.30, 95% CI 0.15-0.44), dementia (OR 3.09, 95% CI 2.10-4.56), neurologic disorders (OR 2.26, 95% CI 1.23-4.15), psychiatric illness (OR 2.74, 95% CI 1.34-5.62), and obstructive sleep apnea (OR 4.17, 95% CI 1.72-10.09) along with several comorbidity evaluation scores and laboratory markers.

CONCLUSION

We identified risk factors consistently associated with the incidence of POD in knee and hip replacement. Strategies and interventions should be implemented to the patients receiving knee or hip replacement with potential risk factors identified in this meta-analysis.