Total hip arthroplasty: Survival and modes of failure

3D preoperative predictions of in vivo hip stability and edge loading for neutral and lipped liners

Hip dislocation is one of the leading causes of failure and revision surgery for total hip arthroplasty. To reduce dislocation rates, lipped liners have been designed with an elevated portion of the rim, to increase jump distance and maintain greater contact area. While it has been documented that lipped liners help reduce dislocation, the objective of this study is to investigate whether lipped liners also help reduce smaller instances of hip micromotion, separation, and edge loading. This study uses an advanced three-dimensional preoperative planning tool to analyze 10 patients, each implanted with both a neutral and lipped liner. Patients within the simulation performed stance phase of gait, and each cup was implanted with the rotation center aligned with the preoperative acetabulum center as well as shifted medially by 2, 4, 6, 8, and 10 mm, yielding 120 total simulations. Specific postoperative outcomes-of-interest included specified component offset, resultant in vivo hip forces, hip separation, and contact area to evaluate edge loading. The planner predicted a reduction in hip separation and an increase in articulating contact area for when using a lipped liner compared to a neutral liner. Additionally, regardless of liner type, increases in hip separation corresponded to decreases in contact area, therefore resulting in edge loading of the liner. Together, this indicates that improper component alignment and offsets may lead to an increase in hip separation and edge loading, but the use of a lipped liner may provide improved stability and resistance to this micromotion.

Bone graft incorporation failure with inappropriate limb load transfer can lead to aseptic acetabular loosening of metal-on-metal prosthesis: A case report

BACKGROUND

Aseptic acetabular loosening can result from various factors that can be categorized into groups: patient-related, surgeon-related and implant-related. We present a case of a 63-year-old patient who at first underwent a total hip arthroplasty (THA) using a metal-on-metal bearing due to hip arthrosis. Follow-up visits revealed no complications after the procedure. Two years after the THA, acetabular component loosening occurred due to subsequent trauma of the opposite hip, necessitating a revision THA using a ceramic-on-ceramic bearing.

CASE SUMMARY

We aim to illustrate a rare case where the primary reason for undergoing THA revision was not only incomplete bone graft incorporation but also improper limb load distribution. Following the revision arthroplasty, a 9-year follow-up visit revealed improvements in all evaluation measures on questionnaire compared to the state before surgery: Harris Hip Score (before surgery: 15; after surgery: 95), Western Ontario and McMaster Universities Arthritis Index (before surgery: 96; after surgery: 0), and Visual Analogue Scale (before surgery: 10; after surgery: 1).

CONCLUSION

Opposite-hip trauma caused a weight transfer to the limb after a THA procedure. This process led to a stress shielding effect, resulting in acetabular component loosening.

Synovial calprotectin in prosthetic joint infection. A systematic review and meta-analysis of the literature

INTRODUCTION

Calprotectin is a protein endowed with antimicrobial properties, rendering it a distinctive marker for infection. Two methods are currently available for the assay of calprotectin: the enzyme-linked immunosorbent assay (ELISA) and the lateral flow test (LFT). We aimed to assess the diagnostic accuracy of synovial fluid calprotectin and to compare the accuracy of the laboratory-based test and the qualitative assessment for the diagnosis of hip and knee prosthetic infection.

MATERIALS AND METHODS

We searched (from inception to November 2023) MEDLINE, Scopus, EMBASE, Web of Science, and Cochrane for studies on calprotectin in the diagnosis of periprosthetic joint infection (PJI). Sensitivity, specificity, positive and negative likelihood ratio (LR), and diagnostic odds ratio were analyzed. The receiver-operating curve for each method was calculated.

RESULTS

We included 14 articles in our meta-analysis, including 902 patients who underwent total hip and knee arthroplasties revision; 331 (37%) had a joint infection according to MSIS, MSIS-modified criteria, ICM 2018 and EBJIS 2021. Considering the false-positive result rate of 6% and false-negative result rate of 7%, pooled sensitivity and specificity were 0.92 (95% CI 0.89-0.94) and 0.93 (0.91-0.95), respectively. The area under the curve (AUC) was 0.93 (95% CI 0.91-0.94). No statistical differences in terms of sensitivity and specificity were found between ELISA and LFT. The pooled sensitivity and specificity of the two calprotectin assessment methods were: LFT 0.90 (95% CI 0.869-0.935) and 0.92 (95% CI 0.894-0.941), respectively; ELISA 0.96 (95% CI 0.914-0.986) and 0.97 (95% CI 0.934-0.988), respectively. The diagnostic odds ratio of the ELISA was superior to that of the LFT (906.6667, 95% CI 271.2686-3030.3712 versus 113.8886, 95% CI 70.4001-184.2414; p < 0.001). The AUC for ELISA and LFT was 0.968 (95% CI 0.944-0.984) and 0.915 (95% CI 0.895-0.933), respectively.

CONCLUSIONS

Detection of synovial calprotectin is an accurate test for diagnosis of hip and knee prosthetic infections. The diagnostic accuracy of the two calprotectin assessment methods is almost comparable. The LFT is a valid, rapid, and more available diagnostic tool, particularly to rule out PJI.

Pseudomonas aeruginosa Bacteriophages and Their Clinical Applications

Antimicrobial resistance poses a serious risk to contemporary healthcare since it reduces the number of bacterial illnesses that may be treated with antibiotics, particularly for patients with long-term conditions like cystic fibrosis (CF). People with a genetic predisposition to CF often have recurrent bacterial infections in their lungs due to a buildup of sticky mucus, necessitating long-term antibiotic treatment. Pseudomonas aeruginosa infections are a major cause of CF lung illness, and P. aeruginosa airway isolates are frequently resistant to many antibiotics. Bacteriophages (also known as phages), viruses that infect bacteria, are a viable substitute for antimicrobials to treat P. aeruginosa infections in individuals with CF. Here, we reviewed the utilization of P. aeruginosa bacteriophages both in vivo and in vitro, as well as in the treatment of illnesses and diseases, and the outcomes of the latter.

High femoral offset as a risk factor for aseptic femoral component loosening in cementless primary total hip arthroplasty

PURPOSE

Lateralized stems in primary cementless total hip arthroplasty (THA) showed to be associated with aseptic femoral loosening. However, femoral head length also affects femoral offset but was not considered so far. This study analyzed the impact of high femoral offset (hFO) combinations, formed by lateralized stems or large femoral head lengths, on aseptic femoral component loosening.

METHODS

Retrospective cohort study was performed including all patients that underwent primary cementless THA at our institution between July 2004 and December 2016. Patients were screened for aseptic femoral component loosening and grouped in aseptic loosening (AL) and non-aseptic loosening (nAL) group. Medical records were screened; implant details were noted and classified in hFO and standard femoral offset (sFO) combinations. Supposed risk factors for aseptic loosening were analyzed.

RESULTS

Two thousand four hundred fifty-nine THA could be included, containing 14 THA (0.6%) with aseptic femoral component loosening. The AL group contained 11 hFO combinations (78.6%), whereas in the nAL group, 1315 hFO combinations (53.8%) were used. Subgroup analysis showed significant difference between two groups for hFO combinations (p = 0.014), age (p = 0.002), NSAR (p = 0.001), and bilateral THA on same day (p = 0.001). The multiple logistic regression analysis showed that hFO combination was the only variable for increased probability of aseptic loosening (OR, 3.7; p = 0.04).

CONCLUSION

High femoral offset combinations, formed by lateralized stems or large femoral head lengths in our collective of standard straight stems implanted by an anterior approach, show a 3.7-fold increased probability for aseptic femoral component loosening. Adjustment of the postoperative protocol may be considered in these cases to ensure proper stem ingrowth.

Risk factors for femoral stem fracture following total hip arthroplasty: a systematic review and meta analysis

BACKGROUND

Femoral stem fracture following total hip arthroplasty (THA) is an infrequent but nevertheless devastating complication, with an increasing worldwide prevalence as demand for primary THA continues to increase. The aim of this study was to perform a systematic review and meta-analysis of risk factors for femoral stem fracture to help identify at risk patients.

METHODS

A systematic search was conducted on EMBASE, MEDLINE and AMED to identify relevant studies. Data regarding study design, source, population, intervention, and outcomes was collated. Data extraction was performed on a custom form generated using Cochrane recommended methodology and analysis of risk factors performed including odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

A total of 15 studies reporting a total of 402 stem fractures in 49 723 THAs were identified. The median time from index procedure to stem fracture was 68 months (IQR 42.5-118) whilst mean age at index surgery was 61.8 years (SD 6.9). Male gender (OR = 3.27, 95% CI = 2.59-4.13, p < 0.001), patient weight above 80 kg (OR = 3.55, 95% CI = 2.88-4.37, p < 0.001), age under 63 years (OR = 1.22, 95% CI = 1.01-1.49, p < 0.001), varus stem alignment (OR = 5.77, 95% CI = 3.83-8.7, p < 0.001), use of modular implants (OR = 1.95, 95% CI = 1.56-2.44, p < 0.01) and undergoing revision arthroplasty (OR = 3.33, 95% CI = 2.70-4.1, p < 0.001) were significant risk factors for prosthetic stem fracture. A risk window of 15 years post-surgery was identified.

CONCLUSIONS

This review concludes that patient weight, younger age, male sex, varus stem alignment, revision arthroplasty and use of modular stems are significant risk factors for femoral stem fracture. Modifying these risk factors where possible may help reduce incidence of femoral stem fracture in at risk patients.

The influence of biological DMARDs on aseptic arthroplasty loosening: a retrospective cohort study

OBJECTIVE

To investigate whether biological DMARDs affect the risk of aseptic loosening after total hip/knee arthroplasty (THA/TKA) in patients with RA.

METHODS

We retrospectively identified all patients suffering from RA who underwent THA/TKA at our academic centre between 2002 and 2015 and linked them with an existing prospective observational RA database at our institution. The risk of aseptic loosening was estimated using radiological signs of component loosening (RCL). A time-dependent Cox regression analysis was used to compare the risk of implant loosening between patients treated with traditional DMARDS and biological DMARDs, or alternately both over time.

RESULTS

A total of 155 consecutive total joint arthroplasties (TJAs) (103 TKA vs 52 THA) was retrospectively included in the study. Mean age at implantation was 59 ± 13 years. Mean follow-up time was 69 ± 43 months. Overall, 48 (31%) TJAs showed signs of RCL, with 28 (27.2%) RCLs occurring after TKA compared with 20 after THA (38.5%). A significant difference regarding the incidence of RCL between the traditional DMARDs group (39 cases of RCL, 35%) and the biological DMARDs group (nine cases of RCL, 21%) (P = 0.026) was observed using the log-rank test. This was also true when using a time-dependent Cox regression with therapy as well as arthroplasty location (hip vs knee) as variables (P = 0.0447).

CONCLUSION

Biological DMARDs may reduce the incidence of aseptic loosening after TJA in patients with RA compared with traditional DMARDs. This effect seems to be more pronounced after TKA than THA.

Investigation of stair ascending and descending activities on the lifespan of hip implants

Total hip arthroplasty (THA) surgeries among young patients are on the increase, so it is crucial to predict the lifespan of hip implants correctly and produce solutions to improve longevity. Current implants are designed and tested against walking conditions to predict the wear rates. However, it would be reasonable to include the additional effects of other daily life activities on wear rates to predict convergent results to clinical outputs. In this study, 14 participants are recruited to perform stair ascending (AS), descending (DS), and walking activities to obtain kinematic and kinetic data for each cycle using marker based Qualisys motion capture (MOCAP) system. AnyBody Modeling System using the Calibrated Anatomical System Technique (CAST) full body marker set are performed Multibody simulations. The 3D generic musculoskeletal model used in this study is a marker-based full-body motion capture model (AMMR,2.3.1 MoCapModel) consisting of the upper extremity and the Twente Lower Extremity Model (TLEM2). The dynamic wear prediction model detailing the intermittent and overall wear rates for CoCr-on-XLPE bearing couple is developed to investigate the wear mechanism under 3D loading for AS, DS, and walking activities over 5 million cycles (Mc) by using finite element modelling technique. The volumetric wear rates of XLPE liner under AS, DS, and walking activities over 5-Mc are predicted as 27.43, 23.22, and 18.84 mm3/Mc respectively. Additionally, the wear rate was predicted by combining stair activities and gait cycles based on the walk-to-stair ratio. By adding the effect of stair activities, the volumetric wear rate of XLPE is predicted as 22.02 mm3/Mc which is equivalent to 19.41% of walking. In conclusion, in this study, the effect of including other daily life activities is demonstrated and evidence is provided by matching them to the clinical data as opposed to simulator test results of implants under ISO 14242 boundary conditions.

Femoral revision in total hip arthroplasty using a cementless modular stem: clinical and radiological results with a 8-year follow-up

INTRODUCTION

Modular femoral components allow for patient-specific restoration of hip joint geometry and the reconstruction of extensive bone defects in revision total hip arthroplasty (THA); however, potential problems of modular implants such as taper corrosion and the risk of implant fracture continue to be of concern. The aim of the present study was to evaluate the clinical and radiological results of a cementless modular revision stem following revision surgery due to aseptic loosening and periprosthetic fracture and to assess patient-reported outcome measures (PROMs) in these patients at mid-term follow-up.

MATERIALS AND METHODS

In this study, a consecutive cohort of 75 patients who underwent primary revision THA at our institution using a modular cementless stem design (MRP-TITAN stem) was retrospectively evaluated at a mean follow-up of 7.7 years. Kaplan-Meier survivorship analyses were performed with revision of the femoral component for any reason as the end point. The Harris-Hip Score, the UCLA Activity Score, the Forgotten Joint Score and the SF-12 Score were used for clinical assessment. We used the Wilcoxon signed rank test to compare pre- and postoperative clinical scores.

RESULTS

Overall stem survival with the endpoint stem re-revision for any reason was 85.4% at a mean follow-up of 7.7 years (range 2.4-14 years). Stem survival was 89.5% in the aseptic loosening group and 78.3% in the periprosthetic fracture group with no statistically significant difference between both groups (p = 0.107). One patient had to be revised due to taper fracture. PROMs improved significantly up to the latest follow-up, and radiographic evaluation showed full osseointegration of all stems in this cohort.

CONCLUSIONS

Revision THA using a modular cementless titanium revision stem demonstrated adequate clinical and radiological results at mid- to long-term follow-up in this cohort. Cementless revision stems are a useful treatment option to restore the anatomy, especially in deformed hips and in complex revision hip arthroplasty. However, there are some significant disadvantages related to an increased risk of mechanical failure such as corrosion/fretting damage and implant fracture. Future high-quality prospective studies with longer follow-up are necessary to confirm the supposed advantages.

Radiographic signs and hip pain 5 years after THA with a cemented stem predict future revision for aseptic loosening: a prospective cohort study

BACKGROUND AND PURPOSE

We aimed to evaluate the long-term predictive value of radiographic abnormality and/or hip pain assessed 5 years following primary total hip arthroplasty (THA) and the occurrence of revision for aseptic loosening between 5 and 25 years postoperatively.

PATIENTS AND METHODS

We included all primary THAs performed between 1996 and 2011 (same uncemented cup, polyethylene-ceramic bearing, 28 mm head, cemented stem) and prospectively enrolled in the institutional registry, for whom baseline and follow-up radiographs were available. At 5 years radiographically we assessed femoral osteolysis and/or stem migration. Pain was evaluated with the Harris Hip pain subscore. Kaplan-Meier survival and Cox regression analyses were performed.

RESULTS

1,317 primary THAs were included. 25 THAs (2%) were revised for aseptic stem loosening. Any abnormal radiographic sign at 5 years was present in 191 THAs (14%). Occasional hip pain was reported by 20% and slight to severe pain by 12% of patients at 5 years. In patients < 60 years, 10 of the 12 later revised for aseptic stem loosening had abnormal radiographs at 5 years vs. 5 of the 13 later revised in those ≥ 60 years. Hazard ratios (HR) were 34 (95% confidence interval [CI] 7-155) in younger vs. 4 (CI 1-11) in the older group. HR for association of hip pain at 5 years with future revision was 3 (CI 1-5).

CONCLUSION

The presence of abnormal radiographic signs 5 years after THA was strongly associated with later revision for aseptic stem loosening, especially in patients < 60 years. The association between pain at 5 years and future revision was much weaker.

An analysis of the prevalence and risk factors of deep vein thrombosis in non-fracture patients awaiting total hip arthroplasty: a retrospective study of 1244 cases

BACKGROUND

Deep vein thrombosis (DVT) has been one of the most dangerous complications in total hip arthroplasty (THA). If a patient's pre-surgical DVT is overlooked, it can easily be mistaken for a post-operative thrombus and lead to an increased risk of DVT during and after surgery. This retrospective study was to explore the incidence and associated risk factors of deep vein thrombosis (DVT) in non-fracture patients before total hip arthroplasty (THA).

METHODS

From September 2015 to September 2020, 1242 patients admitted for THA were enrolled with 1120 patients (90.2%) for primary THA and 122 patients (9.8%) for revision THA. An experienced sonographer performed a bedside ultrasound to detect DVT in bilateral lower limbs preoperatively. Univariate and logistic regression analysis was performed to identify the independent risk factors.

RESULTS

38 patients (3.1%) were detected with preoperative DVT. Univariate analysis showed that age (P < 0.001), D-dimer level (P = 0.002), female patients (P = 0.016), revision THA (P < 0.001), Barthel Index score (P = 0.010) were significantly associated with preoperative DVT. In subgroup comparison, the incidence of DVT increased with age significantly (P < 0.001) and D-dimer level (P < 0.001). In logistic regression analysis, age ≥ 75 years old (odds ratio [OR] 3.678, 95% CI [2.197-18.721], P < 0.001), gender (OR 2.709, 95% CI [1.244-5.896], P = 0.012), higher D-dimer ≥ 0.5 mg/l (OR 6.841, 95% CI [2.197-18.721], P < 0.001) and revision THA (OR 2.240, 95% CI [1.143-5.372], P = 0.05) were confirmed as the independent risk factors.

CONCLUSIONS

The incidence of preoperative DVT in non-fracture patients was 3.1%, with 2.4% in primary THA and 9.0% in revision THA. Age ≥ 75 years old, female, D-dimer ≥ 0.5 mg/l, and revision THA were independent risk factors. When evaluating the risk factors associated with thrombus formation preoperatively, it is important to take these into account before surgery.

Liaw's Ellipse Anteversion Method for Distinguishing Acetabular Component Retroversion from Anteversion on Plain Radiographs

Improper acetabulum component position is a significant risk factor for postoperative dislocation after total hip arthroplasty. Several radiographic two-dimensional methods exist for measuring acetabulum component anteversion, but they cannot distinguish between anteversion and retroversion. "Liaw's version," initially proposed as a simple mathematical standardized two-dimensional method, was modified to the computerized ellipse method, proving superior accuracy to traditional two-dimensional methods. In this article, we demonstrated its application in detecting and measuring retroverted acetabulum component. We obtained anteroposterior pelvis radiographs from a patient undergoing total hip arthroplasty on the day of surgery and 2 weeks postoperatively. The computerized ellipse method was used to measure the acetabulum component orientation. Upon comparison, the difference between θ assigned to be retroverted (9.52-8.56 = 0.96) is much smaller than the difference between θ assigned to be anteverted (23.81-18.86 = 4.95), leading us to determine retroversion. This was further confirmed by computed tomography at the 6-week follow-up. We propose that using the computerized ellipse method to measure Liaw's version can be a valuable tool in identifying acetabulum component retroversion on anteroposterior radiographs during routine postoperative follow-up and retrospective assessments of total hip arthroplasty patients.

Real-world 2-year clinical and economic outcomes among patients receiving a medial collared, triple tapered primary hip system versus other implants for total hip arthroplasty

OBJECTIVE

To evaluate real-world outcomes of patients receiving ACTIS, a medial collared, triple-tapered (MCTT) hip system vs. other implants, for primary total hip arthroplasty (THA).

METHODS

Patients with THA between 2016-2021 from Mercy Healthcare Systems-Orthopedics Database were evaluated. The primary outcome was the 2-year revision. Secondary outcomes included operating room (OR) time, length of stay (LOS), and discharge disposition. Fine Stratification and Weighting (FSW) controlled for baseline characteristic differences between ACTIS and other implant groups. Cox proportional regression evaluated the hazard ratio (HR) for revision.

RESULTS

Among 9,225 patients with 10,205 THAs (mean [SD] age 66.8 [11.3] years, 56.0% female), MCTT was implanted in 1,591 hips and other implants in 8,614 hips. The balanced cohort included all 10,205 procedures (54.2% female; age 65.5 [11.3]; 14.1% Elixhauser index ≥5; 84.5% MCTT, 82.2% other since 2018; obesity 43.6% MCTT, 43.0% other). Two-year revision was 0.9% for MCTT and 1.8% for other implants (p = .021). HR for revision MCTT vs. other was 0.53 (95% CI 0.30-0.92; p = .023). Mean (SD) OR time was 69.07 (18.93) minutes for MCTT, 83.69 (43.88) for other implants (p < .001). LOS was 1.99 (1.15) days for MCTT, 2.45 (2.91) for other implants (p < .001). MCTT patients were more likely to be discharged home (90.7% vs 33.8%, p < .001) and less likely to be discharged to skilled nursing facilities (SNF) (4.2% vs 9.6%, p < .001). One-year cost savings per patient with MCTT was projected at $2,342.

CONCLUSIONS

MCTT patients had fewer revisions, reduced OR time, shorter LOS, more home and less SNF discharge, leading to cost savings.

Bisphosphonates' use and risk of aseptic loosening following total hip arthroplasty: a systematic review

Purpose

The main indication of bisphosphonates (BPs) is osteoporosis treatment. However, there is growing interest in the peri- and postoperative use of BPs to mitigate total hip arthroplasty (THA) aseptic loosening (AL) risk. This systematic review aimed to evaluate the implant survival and the AL rate in patients with elective THA receiving BPs compared to those that do not receive BPs. Secondary outcomes included the comparison of revision rate, postoperative complications, and patients' functional scores.

Methods

This systematic review was conducted under the PRISMA 2020 guidelines with a pre-registered PROSPERO protocol. Three engines and grey literature were searched up until May 2022. Randomized and nonrandomized controlled trials and comparative cohort studies assessing BP and control therapy impact on THA survival were included.

Results

Twelve studies embraced the inclusion criteria. A total of 99 678 patients and 99 696 THAs were included; 10 025 patients received BPs (BP group), and 89 129 made up the control group. The overall revision and AL rates were lower in the BP group (2.17% and 1.85%) than in the control group (4.06% and 3.2%). Periprosthetic fracture (PPF) cases were higher in the BP group (0.24%) than in the control group (0.04%); however, the majority of PPF cases were derived from a single study. Further complication risk was similar between groups. Most studies reported comparable functional scores between groups.

Conclusion

BP treatment after elective THA seems to reduce the overall revision and AL risk. Other complications' risk and functional scores were similar between groups. Further high-quality studies are needed to validate the results due to the multifactorial AL pathogenesis.

Epidemiology of revision hip replacement surgery in the UK over the past 15 years-an analysis from the National Joint Registry

OBJECTIVES

To investigate trends in the incidence rate and main indication for revision hip replacement (rHR) over the past 15 years in the UK.

DESIGN

Repeated national cross-sectional study from 2006 to 2020.

SETTING/PARTICIPANTS

rHR procedures were identified from the National Joint Registry for England, Wales, Northern Ireland, the Isle of Man and the States of Guernsey. Population statistics were obtained from the Office for National Statistics.

MAIN OUTCOME MEASURES

Crude incidence rates of rHR.

RESULTS

The incidence rate of rHR doubled from 11 per 100 000 adults in 2006 (95% CI 10.7 to 11.3) to a peak of 22 per 100 000 adults (95% CI 22 to 23) in 2012, before falling to 17 per 100 000 adults in 2019 (95% CI 16 to 17) (24.5% decrease from peak). The incidence rate of rHR reduced by 39% in 2020 compared with 2019 (during the COVID-19 pandemic). The most frequent indications for rHR between 2006 and 2019 were loosening/lysis (27.8%), unexplained pain (15.1%) and dislocation/instability (14.7%). There were incremental increases in the annual number and incidence rates of rHR for fracture, infection, dislocation/instability and a decrease in rHR for aseptic loosening/lysis.

CONCLUSIONS

The incidence rate of rHR doubled from 2006 to 2012, likely due to high early failure rates of metal-on-metal hip replacements. The incidence of rHR then decreased by approximately 25% from 2012 to 2019, followed by a large decrease during the COVID-19 pandemic. The decrease in the number of rHR performed for aseptic loosening/lysis may reflect improved wear and implant longevity. Increased healthcare resource will be required to care for the increasing numbers of patients undergoing rHR for fracture and infection.

Reactive Peri-Arthroplasty Pseudotumors: A Rare Cause of Hip Pain and Iatrogenic Sciatica

Total hip arthroplasty (THA) is the preferred treatment for patients with hip joint disorders refractory to conservative management. While original implants were designed to articulate a metallic femoral head onto a polyethylene liner, the popularity of "metal-on-metal" (MoM) hip implants surged in the early 21st century due to their perceived superior long-term durability and lower revision rates. However, subsequent follow-up studies showed high failure rates due to inflammatory responses to periprosthetic metallic debris leading to lymphocytic proliferation, soft tissue necrosis or fibrosis, systemic metal toxicity, and/or the development of cystic pseudotumors. Although these discoveries resulted in a significant decrease in MoM THA and revision procedures, the majority of MoM hip implants persist in the adult population. In this case report and review, we report the presentation, diagnostic work-up, and management of an 84-year-old status-post MoM THA who presented with unilateral leg tenderness and poor ambulation secondary to pseudotumor-induced sciatica.

Understanding the 30-day mortality burden after revision total hip arthroplasty

BACKGROUND

Revision total hip arthroplasty (THA) is a challenging procedure that burdens the healthcare system. Despite being associated with worse outcomes relative to its primary counterpart, postoperative mortality after revision THA remains ill-defined. The present study aimed to (1) establish the overall 30-day mortality rate after revision THA and (2) explore the mortality rate stratified by age, comorbidity burden, and aseptic versus septic failure.

METHODS

The American College of Surgeons - National Surgical Quality Improvement Program (ACS-NSQIP) database was retrospectively reviewed for all patients who underwent revision THA from 2011 to 2019. A total of 23,501 patients were identified and grouped into mortality (n = 161) and mortality-free (n = 23,340) cohorts. Patient demographics, comorbidities, and aseptic/septic failure were evaluated.

RESULTS

The overall 30-day mortality was 0.69%. The mortality rate by age group (normalised per 1000 patients) was 0 (18-39 years [Y]), 0.67 (40-49 Y), 1.10 (50-59 Y), 2.58 (60-69 Y), 6.15 (70-79 Y) 19.32 (80-89 Y), and 58.22 (90+Y) (p < 0.001). The mortality rate by ASA classification (normalised per 1000 patients) was 0 (ASA I), 1.47 (ASA II), 6.94 (ASA III), 45.42 (ASA IV), and 200 (ASA V) (p < 0.001). The 30-day mortality rate for the septic and aseptic cohorts was 1.03% and 0.65%, respectively (p = 0.038). CCI scores (p < 0.001), diabetes (p < 0.001), systematic sepsis (p < 0.001), poor functional status (p < 0.001), BMI < 24.9 kg/m2 (p < 0.001), and dirty/infected wounds (p < 0.001) were all associated with increased mortality risk.

CONCLUSIONS

1 in 145 patients will suffer mortality during the 30 days after revision THA. PJI-related revision THA was associated with 1.5-fold increase in 30-day mortality rate compared to its aseptic counterpart. Certain patient determinants and baseline comorbidities, as measured by ASA and CCI scores, were associated with higher 30-day mortality rates. Therefore, it is imperative to identify such risk factors and implement perioperative patient optimisation pathways to mitigate the risk among vulnerable patients.

Readmission rate and healthcare utilization outcomes of computer-assisted fluoroscopy-based hip navigation versus manual total hip arthroplasty

INTRODUCTION

The study evaluates the technology of fluoroscopy-based hip navigation that has shown to improve implant positioning in total hip arthroplasty (THA).

METHODS

Premier Healthcare data for patients undergoing manual THA or fluoroscopy-based hip navigation THA between 1 January 2016-30 September 2021, were analyzed 90- and 365-day post-THA. The primary outcome was inpatient readmission. Secondary outcomes were operating room (OR) time, length of stay, discharge status, and hospital costs. Baseline covariate differences were balanced using fine stratification and analyzed using generalized linear models.

RESULTS

Among 4,080 fluoroscopy-based hip navigation THA and 429,533 manual THA balanced patients, hip-related readmission rates were statistically significantly lower for the fluoroscopy-based hip navigation THA cohort vs. manual THA for both 90-day (odd ratio [95% CI]: 0.69 [0.52 to 0.91] and 365-day (0.63 [0.49 to 0.81] follow-up. OR time was higher with fluoroscopy-based hip navigation THA vs. manual THA (134.65 vs. 132.04 minutes); however, fluoroscopy-based hip navigation THA patients were more likely to be discharged to home (93.73% vs. 90.11%) vs. manual THA. Hospital costs were not different between cohorts at 90- and 365-day post-operative.

CONCLUSIONS

Fluoroscopy-based hip navigation THA resulted in fewer readmissions, greater discharge to home, and similar hospital costs compared to manual THA.

Multi-functional bioactive silver- and copper-doped diamond-like carbon coatings for medical implants

Diamond-like carbon (DLC) coatings doped with bioactive elements of silver (Ag) and copper (Cu) have been receiving increasing attention in the last decade, particularly in the last 5 years, due to their potential to offer a combination of enhanced antimicrobial and mechanical performance. These multi-functional bioactive DLC coatings offer great potential to impart the next generation of load-bearing medical implants with improved wear resistance and strong potency against microbial infections. This review begins with an overview of the status and issues with current total joint implant materials and the state-of-the art in DLC coatings and their application to medical implants. A detailed discussion of recent advances in wear resistant bioactive DLC coatings is then presented with a focus on doping the DLC matrix with controlled quantities of Ag and Cu elements. It is shown that both Ag and Cu doping can impart strong antimicrobial potency against a range of Gram-positive and Gram-negative bacteria, but this is always accompanied so far by a reduction in mechanical performance of the DLC coating matrix. The article concludes with discussion of potential synthesis methods to accurately control bioactive element doping without jeopardising mechanical properties and gives an outlook to the potential long-term impact of developing a superior multifunctional bioactive DLC coating on implant device performance and patient health and wellbeing. STATEMENT OF SIGNIFICANCE: Multi-functional diamond-like carbon (DLC) coatings doped with bioactive elements of silver (Ag) and copper (Cu) offer great potential to impart the next generation of load-bearing medical implants with improved wear resistance and strong potency against microbial infections. This article provides a critical review of the state-of-the-art in Ag and Cu doped DLC coatings, beginning with an overview of the current applications of DLC coatings in implant technology followed by a detailed discussion of Ag/Cu doped DLC coatings with particular focus on the relationship between their mechanical and antimicrobial performance. Finally, it ends with a discussion on the potential long-term impact of developing a truly multifunctional ultra-hard wearing bioactive DLC coating to extend the lifetime of total joint implants.

Dynamic computational wear model of PEEK-on-XLPE bearing couple in total hip replacements

Understanding wear mechanisms is a key factor to prevent primary failures causing revision surgery in total hip replacement (THR) applications. This study introduces a wear prediction model of (Polyetheretherketone) PEEK-on-XLPE (cross-linked polyethylene) bearing couple utilized to investigate the wear mechanism under 3D-gait cycle loading over 5 million cycles (Mc). A 32-mm PEEK femoral head and 4-mm thick XLPE bearing liner with a 3-mm PEEK shell are modeled in a 3D explicit finite element modeling (FEM) program. The volumetric and linear wear rates of XLPE liner per every million cycles were predicted as 1.965 mm³/Mc, and 0.0032 mm/Mc respectively. These results are consistent with the literature. PEEK-on-XLPE bearing couple exhibits a promising wear performance used in THR application. The wear pattern evolution of the model is similar to that of conventional polyethylene liners. Therefore, PEEK could be proposed as an alternative material to the CoCr head, especially used in XLPE-bearing couples. The wear prediction model could be utilized to improve the design parameters with the aim of prolonging the life span of hip implants.

Antimicrobial activity of ion-substituted calcium phosphates: A systematic review

In this systematic review, the antimicrobial effect of ion-substituted calcium phosphate biomaterials was quantitatively assessed. The literature was systematically searched up to the 6th of December 2021. Study selection and data extraction was performed in duplo by two independent reviewers with a modified version of the OHAT tool for risk of bias assessment. Any differences were resolved by consensus or by a referee. A mixed effects model was used to investigate the relation between the degree of ionic substitution and bacterial reduction. Of 1016 identified studies, 108 were included in the analysis. The methodological quality of included studies ranged from 6 to 16 out of 18 (average 11.4). Selenite, copper, zinc, rubidium, gadolinium, silver and samarium had a clear antimicrobial effect, with a log reduction in bacteria count of 0.23, 1.8, 2.1, 3.6, 5.8, 7.4 and 10 per atomic% of substitution, respectively. There was considerable between-study variation, which could partially be explained by differences in material formulation, study quality and microbial strain. Future research should focus on clinically relevant scenarios in vitro and the translation to in vivo prevention of PJI.

Surgeon Estimations of Acetabular Cup Orientation Using Intraoperative Fluoroscopic Imagining Are Unreliable

Background

Accurate acetabular cup orientation is associated with decreased revision rates and improved outcomes of primary total hip arthroplasty. This study assesses surgeon's ability to estimate both the acetabular component inclination and anteversion angles via intraoperative fluoroscopy (IF) images.

Methods

We surveyed orthopedic surgeons to estimate acetabular component inclination and anteversion based on 20 IF images of total hip arthroplasty through a direct anterior approach. Postoperative computed-tomography scans were used to calculate the true inclination and anteversion component angles. The absolute difference between the true and estimated values was calculated to determine the mean and standard deviation of the survey results. Interrater reliability was determined through interclass correlation coefficients.

Results

A majority of surgeons preferred the direct anterior approach (83.3%) and utilized IF during surgery (70%). Surgeons surveyed were on average 5.9° away from the true value of inclination (standard deviation = 4.7) and 8.8° away from the true value of anteversion (standard deviation = 6.0). Respondents were within 5° of both inclination and anteversion in 19.7% of cases, and within 10° in 57.3% of cases. All surgeons were determined to have poor reliability in estimating anteversion (interclass correlation coefficient < 0.5). Only 2 surgeons were determined to have moderate reliability when estimating inclination.

Conclusions

Surgeons, when solely relying on IF for the estimation of anteversion and inclination, are unreliable. Utilization of other techniques in conjunction with IF would improve observer reliability.

Demographic changes and surgery caseloads for hip arthroplasty over the last 50 years: a retrospective study

AIMS OF THE STUDY

Data on the demographic changes over time for hip arthroplasty are rare in Switzerland. The aim of the study was to evaluate the influence of these changes on the distribution of age, gender, operated hip side, place of residence and caseload per surgeon over the last 50 years of hip arthroplasty at the Kantonsspital St. Gallen.

METHODS

For this retrospective explorative study, data were collected from the operating theatre journals of hip replacements performed at Kantonsspital St. Gallen from 1969 to 2019. Every fifth year was included, which resulted in 5-year sampling rate over the observation period. The journals were handwritten until 1999 and digital from 2004 to 2019. The following data were obtained: age, sex, type of hip arthroplasty, side of operated hip, place of residence and name of main surgeon. Apart from overall descriptive statistics, we applied the Mann-Whitney U-test to test for differences in age and the binomial test for categorical variables. A linear regression model was applied to investigate the relationship between patients' ages and historical data of life expectancy of the Swiss population.

RESULTS

We included 2,963 patients, of whom 1,318 were men (median age = 67 yr., p25 = 59 yr., p75 = 74 yr.) and 1,608 women (median age = 72 yr., p25 = 63 yr., p75 = 79 yr.). Overall, women were significantly older than men, irrespective of whether they received primary total hip arthroplasty (median age = 70 yr. vs 66 yr., p25 = 61 yr. vs 58 yr., p75 = 77 yr. vs 73 yr., p <0.001), hemiarthroplasty (median age = 84 yr. vs 78.5 yr., p25 = 78 yr. vs 71 yr., p75 = 89 yr. vs 85 yr., p <0.001) or total revision arthroplasty (median age = 71 yr. vs 70 yr., p25 = 64.25 yr. vs 63 yr., p75 = 78 yr. vs 75 yr., p = 0.036). A trend toward rising median age is evident looking at the whole period observed from 1969 to 2019. Except for women in the total revision arthroplasty group (r = 0.226), a high correlation between increasing median age of patients undergoing hip replacement and life expectancy was found (r ≥0.663). Significantly more primary total hip prostheses (p = 0.003) and hip hemiprostheses (p <0.001) were implanted in women than in men between 1969 and 2019. Overall, no significant difference in side distribution was seen in the primary total hip arthroplasty (p = 0.061), total revision arthroplasty (p = 1.000) and hemiarthroplasty (p = 0.365) group. In contrast to earlier years, most patients in recent years are operated on by high-volume surgeons (>50 operations per surgeon per year).

CONCLUSIONS

Demographic changes of patients undergoing total hip replacement reflect the overall demographic changes in the Swiss population. Over the last 50 years the indication for prosthetic hip replacements has not been extended to younger ages. The caseload in hip arthroplasty has changed over the last 50 years towards high-volume surgeons.

The promising role of bacteriophage therapy in managing total hip and knee arthroplasty related periprosthetic joint infection, a systematic review

PURPOSE

Total hip and knee arthroplasty periprosthetic joint infection (PJI) poses a management dilemma owing to the emergence of resistant organisms. A promising option is Bacteriophage therapy (BT) was used as an adjuvant for PJI management, aiming at treating resistant infections, decreasing morbidity, and mortality. The current review aimed to demonstrate the role and safety of using BT as an adjuvant to treat PJIs.

METHODS

A systematic search was performed through four databases (Embase, PubMed, Web of Science, and Scopus) up to March 2022, according to the predetermined inclusion and exclusion criteria.

RESULTS

Our systematic review included 11 case reports of 13 patients in which 14 joints (11 TKAs and three THAs) were treated. The patients' average age was 73.7 years, underwent an average of 4.5 previous surgeries. The most common organism was the Staphylococcus aureus species. All patients underwent surgical debridement; for the 13 patients, eight received a cocktail, and five received monophage therapy. All patients received postoperative suppressive antibiotic therapy. After an average follow-up of 14.5 months, all patients had satisfactory outcomes. No recurrence of infection in any patient. Transaminitis complicating BT was developed in three patients, needed stoppage in only one, and the condition was reversible and non-life-threatening.

CONCLUSION

BT is a safe and potentially effective adjuvant therapy for treating resistant and relapsing PJIs. However, further investigations are needed to clarify some BT-related issues to create effective and reproducible therapeutics. Furthermore, new ethical regulations should be implemented to facilitate its widespread use.

Sarcopenia Is Associated with an Increased Risk of Postoperative Complications Following Total Hip Arthroplasty for Osteoarthritis

Sarcopenia is a state of catabolic muscle wasting prevalent in geriatric patients. Likewise, osteoarthritis is an age-related musculoskeletal disease affecting patients with similar demographics. Late-stage hip osteoarthritis is often treated with total hip arthroplasty (THA). As sarcopenia influences the surgical outcomes, this study aimed to assess the impact of sarcopenia on the outcomes of THA. A 1:3 matched case-control study of sarcopenic to control patients was performed using a large national database. In total, 3992 patients were analyzed. Sarcopenic patients undergoing THA were more likely to experience dislocation (odds ratio (OR) = 2.19, 95% confidence interval (CI) 1.21-3.91) within 1 year of THA. Furthermore, sarcopenic patients had higher urinary tract infection rates (OR = 1.79, CI 1.32-2.42) and a greater risk of 90-day hospital readmission (hazard ratio (HR) = 1.39, CI 1.10-1.77). Sarcopenic patients experienced more falls (OR = 1.62, CI 1.10-2.39) and fragility fractures (OR = 1.77, CI 1.34-2.31). Similarly, sarcopenic patients had higher day of surgery costs (USD 13,534 vs. USD 10,504) and 90-day costs (USD 17,139 vs. USD 13,394) compared with the controls. Ultimately, sarcopenic patients undergoing THA experience higher rates of postoperative complications and incur greater medical costs. Given the potential risks, orthopedic surgeons may consider treating or reducing the severity of sarcopenia before surgery.

Developing Patient-Specific Statistical Reconstructions of Healthy Anatomical Structures to Improve Patient Outcomes

There are still numerous problems with modern joint replacement prostheses, which negatively influence patient health and recovery. For example, it is especially important to avoid failures and complications following hip arthroplasty because the loss of hip joint function is commonly associated with increased demand on the healthcare system, reoperation, loss of independence, physical disability, and death. The current study uses hip arthroplasty as a model system to present a new strategy of computationally generating patient-specific statistical reconstructions of complete healthy anatomical structures from computed tomography (CT) scans of damaged anatomical structures. The 3D model morphological data were evaluated from damaged femurs repaired with prosthetic devices and the respective damaged femurs that had been restored using statistical reconstruction. The results from all morphological measurements (i.e., maximum femoral length, Hausdorff distance, femoral neck anteversion, length of rotational center divergence, and angle of inclination) indicated that the values of femurs repaired with traditional prostheses did not fall within the +/-3 standard deviations of the respective patient-specific healthy anatomical structures. These results demonstrate that there are quantitative differences in the morphology of femurs repaired with traditional prostheses and the morphology of patient-specific statistical reconstructions. This approach of generating patient-specific statistical reconstructions of healthy anatomical structures might help to inform prosthetic designs so that new prostheses more closely resemble natural healthy morphology and preserve biomechanical function. Additionally, the patient-specific statistical reconstructions of healthy anatomical structures might be valuable for surgeons in that prosthetic devices could be selected and positioned to more accurately restore natural biomechanical function. All in all, this contribution establishes the novel approach of generating patient-specific statistical reconstructions of healthy anatomical structures from the CT scans of individuals' damaged anatomical structures to improve treatments and patient outcomes.

Mechanical failure of total hip arthroplasties and associated risk factors

INTRODUCTION

Mechanical failure of total hip arthroplasties is a rare but devastating complication. With increasing numbers in primary arthroplasty implantation, revision surgeries are indicated more often. Therefore, understanding the mechanism and the location of failure is essential in determining proper treatment. Aim of this study was to identify mechanical failures of all total hip arthroplasties performed in a major academic center as well as the associated risk factors such as BMI and sports.

METHODS

A retrospective trial was conducted using our prospective arthroplasty database. Database was searched for all patients presenting with mechanical failures of total hip arthroplasty (THA) to the emergency department between 2011 and 2019. All medical charts and radiographs as well as surgical reports were analyzed to identify demographics, implant choice in addition to location of failure and subsequent treatment.

RESULTS

In total, 13 patients suffering from mechanical total hip implant failure were found. The femoral neck (conus) was broken in four patients, the stem in five cases, one broken inlay, two cup failures and one conus dislocation. The mean BMI was 31.42 ± 5.29 kg/m² including five patients who have obesity class II. In all cases, revision surgeries were indicated. No structural causes or underlying risk factors such as repeated physical load (i.e. in sports) were identified.

CONCLUSION

Implant failure does not seem to correlate with participation in sports or BMI. Catastrophic failure of implants is a technical challenge requiring special extraction instruments that can be difficult even for experienced surgeons. It should be noted that functional outcome is often worse for this group of patients after surgery than comparing against those revised for loosening.

LEVEL OF EVIDENCE

III, Retrospective Trial.

Abductor muscle function after anterolateral approach in patients with unilateral end-stage hip osteoarthritis undergoing total hip arthroplasty: A prospective study

Background

Total hip arthroplasty (THA) is a successful procedure for treating end-stage hip osteoarthritis (OA). Regarding the surgical approach for THA, the anterolateral (AL) approach, which requires anterior hemimyotomy of the gluteus medius muscle, has shown a long-term favorable outcome. However, to date, complete information related to hip abductor muscle outcomes after the AL approach is unavailable. This study therefore aimed to evaluate the postoperative outcome of patients who undergo THA using the AL approach in terms of hip abductor muscle recovery, pain, function, and muscle healing status.

Methods

Twenty patients diagnosed with unilateral end-stage hip OA underwent cementless THA with the AL approach. All patient procedures were performed by a single surgeon. Preoperative and postoperative data were collected at 2-week, 6-week, 3-month, and 6-month follow-up periods. Hip abductor muscle power was measured via handheld dynamometer. The healing of the musculotendinous repair was evaluated with magnetic resonance imaging at 9 months.

Results

After THA, hip abductor muscle power in the operated hip significantly increased as early as 3 months post-procedure when compared with the preoperative value (p < 0.05). The other parameters-including pain score, Harris hip score, and WOMAC score-significantly improved as early as 2 weeks post-operation (p < 0.05). In all patients, MRI scans showed good healing of the muscle repair site without a gap in the gluteus medius muscle. However, three patients (15%) had some fibrosis and tendon swelling at the repair site.

Conclusion

This study demonstrated that patients with end-stage hip OA could experience significantly improved hip abductor motor function as early as 3 months after undergoing THA with the AL approach. Moreover, despite patients experiencing anterior hemimyotomy of the gluteus medius muscle, no significant complications emerged at the muscle repair site in the AL approach.

Vitamin D Metabolic Pathway Components in Orthopedic Patientes-Systematic Review

Vitamin D takes part in the functioning of many processes that ensure the homeostasis of the body. In orthopedics, it is indicated as an inseparable element ensuring proper bone growth and functioning, and its deficiencies are indicated in various diseases, mainly in the proper structure and function of the skeleton. In this review, we focus on the most important components of the vitamin D metabolic pathway, in correlation with selected orthopedic conditions. Records were obtained from the PubMed database in a timeline of 2010-2022. The keywords were as follows: vitamin D/cholesterol/vitamin D binding protein/ VDBP/Cytochrome/CYP24A1/CYP 27B1/Vitamin D receptor/VDR/ + diseases (ACL reconstruction, rotator cuff, arthroplasty knee/hip/shoulder). The recent original studies were analyzed, discussed, and the most important data were shown. The vast majority of articles concern the metabolite of vitamin D (25(OH)D), which is measured as a standard in diagnostic laboratories. Even though there is a lot of valuable information in the literature, we believe that the other elements of the vitamin D pathway also deserve attention and suggest their research in correlation with orthopedic disorders to supplement the missing knowledge on this topic.

SuperPath® vs. direct anterior approach : A retrospective comparison between two minimally invasive approaches in total hip arthroplasty

OBJECTIVE

Minimally invasive approaches are subject to controversy in orthopedic surgery. The aim of the current study was to compare the radiographic parameters between two minimally invasive approaches in total hip arthroplasty.

MATERIAL AND METHODS

Between January 2018 and February 2019, the radiographic parameters of 80 patients undergoing total hip arthroplasty via minimally invasive approaches (DAA: n = 40; SuperPath® SP: n = 40) have been measured. The radiographic analysis was performed with digital software tool mediCad® (HECTEC™ GmbH, Landshut, Germany).

RESULTS

Patients treated with DAA showed significantly higher inclination (SP: 39.7° ± 7.3° vs. DAA: 44.7° ± 5.3°) and significantly lower cup anteversion values (SP: 31.2° ± 7.9° vs. DAA: 27. 5° ± 5.3°, p < 0.001) than patients undergoing THA via SP postoperatively. The horizontal femoral offset was neither preoperatively nor postoperatively higher in DAA than in SP cohort (preoperative: p = 0.71, postoperative: p = 0.25) (preoperative: SP:37.2 mm ± 7.3 vs. DAA 38.2 mm ± 7.5; postoperative: SP: 38.0 mm ± 7.2 vs. DAA: 40.5 mm ± 7.0). At both times, the acetabular offset was significantly higher in DAA cohort than in SP cohort (preoperative: SP: 32.9 mm ± 5.9 vs. DAA: 36.8 mm ± 4.9; postoperative: SP: 28.9 mm ± 4.2 vs. DAA: 33.4 mm ± 3.8) (preoperative: 0.001; postoperative: p < 0.001). The vertical height was preoperatively and postoperatively not significantly higher in SP cohort than in DAA cohort (preoperative: SP: 16.1 mm ± 4.1 vs. DAA: 15.5 mm ± 4.9; postoperative: SP: 16.6 mm ± 4.6 vs. DAA: 16.1 mm ± 4.6) (preoperative: p = 0.77; postoperative: p = 0.58). The preoperatively existing leg length discrepancy of the affected leg could be compensated via surgery without showing significant differences between the two cohorts (preoperative: SP: -3.2 mm ± 5.4 vs. DAA: 1.9 mm ± 4.9; postoperative: SP: 1.5 mm ± 5.4 vs. DAA: 4.8 mm ± 5.6) (preoperative: p = 0.34; postoperative: p = 0.09).

CONCLUSION

The current study demonstrates suitable cup positioning and stem alignment in the coronal plane using minimal-invasive approaches DAA and Superpath®.

Extended Trochanteric Osteotomy Closure Performed Before or After Canal Preparation and Stem Impaction Does Not Affect Axial Stability

BACKGROUND

An extended trochanteric osteotomy (ETO) safely addresses femoral component removal during challenging revision total hip arthroplasty. However, no prior study has evaluated whether a difference in axial stability exists between ETO closure performed before (reconstitution) or after (scaffolding) canal preparation and stem impaction. We hypothesized that given the absence of clinical reports of outcome differences despite the wide use of both practices, no significant difference in the initial axial stability would exist between the 2 fixation techniques.

METHODS

ETOs were performed and repaired using the reconstitution technique for the 6 right-sided femora and the scaffolding technique for the six left-sided femora. The 195-mm long, 3.5°-tapered splined titanium monobloc stems were impacted into 6 matched pairs of human fresh cadaveric femora. Three beaded cables were placed in a standardized fashion on each specimen, 1 for prophylaxis against osteotomy propagation during reaming/impaction and 2 to close the ETO. Stepwise axial loading was performed to 2600 N or until failure, which was defined as subsidence >5 mm or femoral/cable fracture.

RESULTS

All specimens successfully resisted axial testing, with no stem in either ETO repair group subsiding >2 mm. The mean subsidence for the reconstitution group was 0.9 ± 0.4 mm, compared to 1.2 ± 0.5 mm for the scaffolding group (P = .2).

CONCLUSION

In this cadaveric model with satisfactory proximal bone stock, no difference existed between the reconstitution and scaffolding ETO repair techniques, and both provide sufficient immediate axial stability in a simulated revision total hip arthroplasty setting under physiologic loads.

Differences in Patient-Reported Outcome Measures Between Primary and Revision Total Hip Arthroplasty: Realistic Patient Expectations for Patients With Low Baseline Activity

Primary total hip arthroplasty (pTHA) and revision total hip arthroplasty (rTHA) are not often compared in terms of patient-reported outcome measures (PROMs). However, surgeons and patients need to better understand the differences in PROMs between primary and revision surgery to set realistic patient expectations and recovery milestones. A matched cohort study of pTHA to rTHA was performed with our arthroplasty database of a single surgeon's experience from 2012 to 2018. There was a significant difference in both pre-operative assessment and change from preoperative to postoperative assessment of the PROMs. Patients undergoing pTHA had higher visual analog scale (VAS) pain scores (67.9 vs 57.9, P=.004). Those undergoing rTHA had higher Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (57.1 vs 50.1, P=.008) and Veterans RAND 12 Item Health Survey (VR-12) (33.5 vs 33.1, P=.01) scores. However, a significant change was noted in the difference from preoperative to postoperative scores between the pTHA and rTHA groups: Harris Hip Score (HHS) total score (pTHA 30.7 vs rTHA 4.4, P<.001), WOMAC score (pTHA 29.3 vs rTHA 12.2, P<.001), and VAS pain score (pTHA -48.3 vs rTHA -26.5, P<.001) as well as groin pain (pTHA 1.4% vs rTHA 7.1%, P=.02). Further, PROMs after rTHA were inferior to those after pTHA with several outcome instruments, including HHS, WOMAC score, and VAS pain score. In addition, groin pain was significantly greater in the rTHA cohort compared with the pTHA cohort at the latest follow-up. This study allows surgeons and patients to better understand the differences in PROMs to set realistic patient expectations and recovery milestones. [Orthopedics. 2022;45(4):251-255.].

Postoperative Musculoskeletal Imaging and Interventions Following Hip Preservation Surgery, Deformity Correction, and Hip Arthroplasty

Total hip arthroplasty and hip preservation surgeries have substantially increased over the past few decades. Musculoskeletal imaging and interventions are cornerstones of comprehensive postoperative care and surveillance in patients undergoing established and more recently introduced hip surgeries. Hence the radiologist's role continues to evolve and expand. A strong understanding of hip joint anatomy and biomechanics, surgical procedures, expected normal postoperative imaging appearances, and postoperative complications ensures accurate imaging interpretation, intervention, and optimal patient care. This article presents surgical principles and procedural details pertinent to postoperative imaging evaluation strategies after common hip surgeries, such as radiography, ultrasonography, computed tomography, and magnetic resonance imaging. We review and illustrate the expected postoperative imaging appearances and complications following chondrolabral repair, acetabuloplasty, osteochondroplasty, periacetabular osteotomy, realigning and derotational femoral osteotomies, and hip arthroplasty.

When is Surgery Performed? Trends, Demographic Associations, and Phenotypical Characterization of Baseline Patient-Reported Outcomes Before Total Hip Arthroplasty

BACKGROUND

Evaluating trends and drivers of baseline patient-reported outcome measures (PROMs) is critical to understanding when patients and providers elect to undergo surgery. We aimed to assess the following: (1) 5-year trends in baseline PROMs pre-THA (total hip arthroplasty) stratified by patient determinants; (2) patient factor associated with poor preoperative hip pain/function; (3) phenotypes of combined pain/function PROMs at baseline; and (4) intersurgeon variability in PROM thresholds at surgery.

METHODS

A prospective cohort of 6,902 primary THAs was enrolled (January 2016 to December 2020). Patient/surgeon details and PROMs were collected at point of care preoperatively. Outcomes included trends (5 years; 20 quarters) in Hip disability and Osteoarthritis Outcome Score (HOOS)-Pain and HOOS-PS (Physical Function Short-Form), stratified by patient demographics. Patients were further classified into phenotype categories of above or equal to median pain/function (P+PS+); below median pain/function (P-PS-); above or equal to median pain but below median function (P+PS-); and below median pain but above or equal to median function (P-PS+).

RESULTS

Baseline HOOS-Pain was consistent across the study period (P-trend = .166), while HOOS-PS demonstrated increasing function (P-trend = .015). Such trends were appreciable in males, females, and White (P-trend < .001, each) but not Black patients (P-trend = .67). Higher odds ratio (OR) of low baseline HOOS-Pain and HOOS-PS were detected among females (HOOS-Pain: OR 1.75, 95% confidence interval [CI] 1.55-1.98, P < .001; HOOS-PS: OR 1.56, 95% CI 1.38-1.77, P < .001), Black patients (HOOS-Pain: OR 1.64, 95% CI 1.35-2.82, P < .001; HOOS-PS: OR 1.59, 95% CI 1.34-1.89, P < .001), and smokers (HOOS-Pain: OR 1.56, 95% CI 1.29-1.89, P < .001; HOOS-PS: OR 1.52, 95% CI 1.25-1.85, P < .001). The P-PS- cohort (32.4%) had lowest age (65.2 ± 11.1 years), highest body mass index (31.6 ± 6.9 kg/m²), females (64.8%), Black (15.8%), and current smokers (12.2%). There was significant intersurgeon preoperative PROM variation in HOOS-Pain and HOOS-PS (P < .001, each).

CONCLUSION

In contrast to the general population, Black patients have consistently received THA at lower functional levels throughout the 5-year period. Females, smokers, and Black patients were more likely to have poorer pain and function at THA. PROMs assessment as combined pain-function phenotypes may provide a more comprehensive interpretation of patient status preoperatively.

Deep Learning for Radiographic Measurement of Femoral Component Subsidence Following Total Hip Arthroplasty

Femoral component subsidence following total hip arthroplasty (THA) is a worrisome radiographic finding. This study developed and evaluated a deep learning tool to automatically quantify femoral component subsidence between two serial anteroposterior (AP) hip radiographs. The authors' institutional arthroplasty registry was used to retrospectively identify patients who underwent primary THA from 2000 to 2020. A deep learning dynamic U-Net model was trained to automatically segment femur, implant, and magnification markers on a dataset of 500 randomly selected AP hip radiographs from 386 patients with polished tapered cemented femoral stems. An image processing algorithm was then developed to measure subsidence by automatically annotating reference points on the femur and implant, calibrating that with respect to magnification markers. Algorithm and manual subsidence measurements by two independent orthopedic surgeon reviewers in 135 randomly selected patients were compared. The mean, median, and SD of measurement discrepancy between the automatic and manual measurements were 0.6, 0.3, and 0.7 mm, respectively, and did not demonstrate a systematic tendency between human and machine. Automatic and manual measurements were strongly correlated and showed no evidence of significant differences. In contrast to the manual approach, the deep learning tool needs no user input to perform subsidence measurements. Keywords: Total Hip Arthroplasty, Femoral Component Subsidence, Artificial Intelligence, Deep Learning, Semantic Segmentation, Hip, Joints Supplemental material is available for this article. © RSNA, 2022.

Total Hip Replacement in Patients with Rheumatoid Arthritis: Trends in Incidence and Complication Rates Over 35 Years

INTRODUCTION

Advances in rheumatoid arthritis (RA) management have made disease remission achievable. We evaluated trends in total hip replacement (THR) and postoperative outcomes in patients with RA in Western Australia (WA) over more than three decades.

METHODS

This was a retrospective analysis of routinely collected prospective data from a state-wide registry containing longitudinally linked administrative health data based on International Classification of Diseases (ICD) diagnostic and procedural codes. We included patients with two or more diagnostic codes for RA (between 1980 and 2015) and studied THR incidence rates (THR IR) and complication rates (revision, peri-prosthetic fracture, infection, venous thrombosis, and mechanical loosening). Survival rates were estimated by Kaplan-Meier method and predictors analyzed by Cox regression.

RESULTS

We followed 9201 RA patients over 111,625 person-years, during which 1560 patients (16.9%) underwent THR. From 1985 to 2015, THR IR (per 1000 RA patient-years) decreased from 20.8 (95% CI 20.1-21.5) to 7.3 (95% CI 7.2-7.5), and 5-year THR-free survival increased from 84.3 to 95.3% (1980-2015). Ten-year prosthetic survival was 91.2%. Complication rates in the first 5 years post-THR decreased significantly from 13.1 to 3.7% (p < 0.001). Mechanical complications such as loosening and periprosthetic fracture rates decreased significantly (> 35%, P < 0.05), while infection and revision did not change over the observation period (p > 0.05).

CONCLUSIONS

Over the last 30 years in RA patients, THR IR and mechanical complication rates decreased significantly, but the medical complication of infection has not changed significantly.

An Online Learning Tool to Obtain, Optimize, and Interpret Radiographs During Total Hip Arthroplasty

Total hip arthroplasty (THA) is a common orthopedic procedure which has been growing in popularity with the elderly population. With more surgeons completing anterior THAs, intraoperative radiographs have become commonplace. Unfortunately, there is a lack of education in regard to obtaining, optimizing, and interpreting these radiographs. The purpose of this study was to develop and test the efficacy of an online learning tool that medical students, residents, and C-arm technicians could use to improve their understanding of THA radiography. The learning tool taught users how to obtain an optimal AP pelvis radiograph and how to interpret radiographs so THA components could be placed in their optimal position. This learning tool was sent to medical students, orthopedic surgery residents, and C-arm technicians along with a pre-test, post-test, and feedback survey. Twenty users (eleven medical students and nine orthopedic surgery residents) completed the learning tool. Post-test scores (M=96.4%, SD=2.9%) were significantly greater than pre-test scores (M=68.3%, SD=23.9%) for all users (t=5.5069, P<.0001). The user's level of training was positively correlated with pre-test scores. Surveys from the users revealed that the learning tool provided significant learning opportunities, was relatively easy to understand, but was slightly too long. Users felt that this learning tool would be best suited for senior medical students, junior orthopedic surgery residents, and C-arm technicians. With the positive results of this study, the authors hope to further develop this learning tool for widespread adoption and to develop similar learning tools in the future.

Mesenchymal Stromal Cells (MSCs) Isolated from Various Tissues of the Human Arthritic Knee Joint Possess Similar Multipotent Differentiation Potential

(1) Background: The mesenchymal stromal cells (MSCs) of different tissue origins are applied in cell-based chondrogenic regeneration. However, there is a lack of comparability determining the most suitable cell source for the tissue engineering (TE) of cartilage. The purpose of this study was to compare the in vitro chondrogenic potential of MSC-like cells from different tissue sources (bone marrow, meniscus, anterior cruciate ligament, synovial membrane, and the infrapatellar fat pad removed during total knee arthroplasty (TKA)) and define which cell source is best suited for cartilage regeneration. (2) Methods: MSC-like cells were isolated from five donors and expanded using adherent monolayer cultures. Differentiation was induced by culture media containing specific growth factors. Transforming growth factor (TGF)-ß1 was used as the growth factor for chondrogenic differentiation. Osteogenesis and adipogenesis were induced in monolayer cultures for 27 days, while pellet cell cultures were used for chondrogenesis for 21 days. Control cultures were maintained under the same conditions. After, the differentiation period samples were analyzed, using histological and immunohistochemical staining, as well as molecularbiological analysis by RT-PCR, to assess the expression of specific marker genes. (3) Results: Plastic-adherent growth and in vitro trilineage differentiation capacity of all isolated cells were proven. Flow cytometry revealed the clear co-expression of surface markers CD44, CD73, CD90, and CD105 on all isolated cells. Adipogenesis was validated through the formation of lipid droplets, while osteogenesis was proven by the formation of calcium deposits within differentiated cell cultures. The formation of proteoglycans was observed during chondrogenesis in pellet cultures, with immunohistochemical staining revealing an increased relative gene expression of collagen type II. RT-PCR proved an elevated expression of specific marker genes after successful differentiation, with no significant differences regarding different cell source of native tissue. (4) Conclusions: Irrespective of the cell source of native tissue, all MSC-like cells showed multipotent differentiation potential in vitro. The multipotent differentiation capacity did not differ significantly, and chondrogenic differentiation was proven in all pellet cultures. Therefore, cell suitability for cell-based cartilage therapies and tissue engineering is given for various tissue origins that are routinely removed during total knee arthroplasty (TKA). This study might provide essential information for the clinical tool of cell harvesting, leading to more flexibility in cell availability.

Staphylococcus aureus genotype variation among and within periprosthetic joint infections

Staphylococcus aureus is a common organism in orthopedic infections, but little is known about the genetic diversity of strains during an infectious process. Using periprosthetic joint infection (PJI) as a model, a prospective study was designed to quantify genetic variation among S. aureus strains both among and within patients. Whole genome sequencing and multilocus sequence typing was performed to genotype these two populations at high resolution. In nasal cultures, 78% of strains were of clonal complexes CC5, CC8, and CC30. In PJI cultures, only 63% could be classified in these common clonal complexes. The PJI cultures had a larger proportion of atypical strains, and these atypical strains were associated with poor host status and compromised immune conditions. Mutations in genes involved in fibronectin binding (ebh, fnbA, clfA, and clfB) systematically distinguished later PJI isolates from the first PJI isolate from each patient. Repeated mutations in S. aureus genes associated with extracellular matrix binding were identified, suggesting adaptive, parallel evolution of S. aureus during the development of PJI.

Revision Risk in a Cohort of US Patients Younger Than 55 Undergoing Primary Elective Total Hip Arthroplasty

BACKGROUND

As indications for elective total hip arthroplasty (THA) expand to younger patients, we sought to (1) compare revision risk following primary elective THA in patients <55 years at the time of their THA to patients aged ≥65 years and (2) identify specific risk factors for revision in patients <55 years.

METHODS

A Kaiser Permanente's total joint replacement registry was used to conduct a cohort study including primary elective THA patients aged ≥18 (2001-2018). In total, 11,671 patients <55 years and 53,106 patients ≥65 years were included. Multiple Cox regression was used to evaluate cause-specific revision risk, including septic revision, aseptic loosening, instability, and periprosthetic fracture. Stepwise Cox regression was used to identify patient and surgical factors associated with cause-specific revision in patients <55 years.

RESULTS

Patients <55 years had a higher risk of septic revision (hazard ratio [HR] = 1.30, 95% confidence interval [CI] = 1.02-1.66), aseptic loosening (HR = 2.60, 95% CI = 1.99-3.40), and instability (HR = 1.35, 95% CI = 1.09-1.68), but a lower risk of revision for periprosthetic fracture (HR = 0.36, 95% CI = 0.22-0.59) compared to patients aged ≥65 years. In the <55 age group, risk factors for septic revision included higher body mass index, drug abuse, and liver disease. Hypertension, anterior approach, and ceramic-on-ceramic were associated with aseptic loosening. White race, American Society of Anesthesiologists classification ≥3, smoker, paralysis, posterior approach, ceramic-on-ceramic, and smaller head diameter were associated with instability.

CONCLUSION

Identified risk factors varied depending on the cause for revision. Although septic revisions were related to patient characteristics, more modifiable factors, such as implant or surgical approach, were associated with revision due to aseptic loosening and instability.

LEVEL OF EVIDENCE

III.

Impaired regenerative capacity and senescence-associated secretory phenotype in mesenchymal stromal cells from samples of patients with aseptic joint arthroplasty loosening

Aseptic loosening of total hip and knee joint replacements is the most common indication for revision surgery after primary hip and knee arthroplasty. Research suggests that exposure and uptake of wear by mesenchymal stromal cells (MSC) and macrophages results in the secretion of proinflammatory cytokines and local osteolysis, but also impaired cell viability and regenerative capacity of MSC. Therefore, this in vitro study compared the regenerative and differentiation capacity of MSC derived from patients undergoing primary total hip arthroplasty (MSCprim) to MSC derived from patients undergoing revision surgery after aseptic loosening of total hip and knee joint implants (MSCrev). Regenerative capacity was examined by measuring the cumulative population doubling (CPD) in addition to the number of passages until cells stopped proliferating. Osteogenesis and adipogenesis in monolayer cultures were assessed using histological stainings. Furthermore, RT-PCR was performed to evaluate the relative expression of osteogenic and adipogenic marker genes as well as the expression of markers for a senescence-associated secretory phenotype (SASP). MSCrev possessed a limited regenerative capacity in comparison to MSCprim. Interestingly, MSCrev also showed an impaired osteogenic and adipogenic differentiation capacity compared to MSCprim and displayed a SASP early after isolation. Whether this is the cause or the consequence of the aseptic loosening of total joint implants remains unclear. Future research should focus on the identification of specific cell markers on MSCprim, which may influence complication rates such as aseptic loosening of total joint arthroplasty to further individualize and optimize total joint arthroplasty.

Pelvic tilt and functional acetabular position after total hip arthroplasty: an EOS 2D/3D radiographic study

PURPOSE

In total hip arthroplasty (THA), the functional anatomy of the spinopelvic unit should be taken into account to provide the correct functional positioning of the implant. The relationship between the spine and the pelvis in the sagittal plane is represented by pelvic tilt (PT). The sacral slope (SS) has been proposed as a more reliable parameter than the anterior pelvic plane (APP) to express the PT. This study investigated the relationship between the APP and the SS; and the relationship between the APP and the SS, respectively, with the postoperative acetabular orientation.

METHODS

45 patients undergoing primary THA were prospectively enrolled. The EOS 2D/3D system was used to perform the radiographic evaluation before and 3 months after surgery. The following parameters were measured in both standing and sitting position: SS, APP, acetabular anteversion (AA) and inclination (AI).

RESULTS

The SS values did not show any correlation with the values of the APP angle. The changes of the SS in the transition from the standing to the sitting position significantly correlated with the changes of the AA (r = -0.61; p < 0.0001). A weak correlation was found between the APP angle and the AA in standing position (r = -0.35; p = 0.02).

CONCLUSIONS

The SS accurately expresses the functional orientation of the pelvis in the sagittal plane, and the functional orientation of the cup after hip replacement. Therefore, SS could be taken into account by navigation systems in order to achieve a patient-specific functional position of the acetabular cup.

Antibiotic Therapy in 2-Stage Revision for Periprosthetic Joint Infection: A Systematic Review

BACKGROUND

Patients undergoing total joint arthroplasty (TJA) are at risk for developing periprosthetic joint infection (PJI). To treat PJI, orthopaedic surgeons can perform 1-stage or 2-stage revision arthroplasty. Although 2-stage revision yields superior long-term outcomes, the optimal antibiotic therapy duration and route of administration between stages remain uncertain. In this systematic review, we aimed to identify if variations in antibiotic therapy, duration, and administration during 2-stage hip or knee revision arthroplasty affect PJI eradication rates and surgical outcome measures.

METHODS

A literature search was performed using the PubMed and Google Scholar databases to identify all original reports from January 2000 to June 2021 involving 2-stage revision arthroplasty to treat PJI. Studies were included if they specified antibiotic duration, an intravenous (IV) route of antibiotic administration, type of antibiotic, and 2-stage revision PJI eradication rate and had a mean or median follow-up of at least 2 years after the second-stage operation. Included studies were classified into 3 groups based on the length of IV antibiotic therapy after prosthesis explantation: prolonged IV antibiotic therapy of 4 to 6 weeks, shortened IV antibiotic therapy of ≤2 weeks, and shortened course of IV antibiotic therapy followed by 6 to 12 weeks of oral antibiotics.

RESULTS

Nine studies were included. Three studies utilizing a prolonged IV antibiotic therapy had PJI eradication rates of 79% to 96%. Four studies using a shortened IV antibiotic therapy showed PJI eradication rates of 88% to 100%. Finally, 2 studies utilizing a shortened course of IV antibiotic therapy with oral antibiotics had PJI eradication rates of 95% and 97%. There was no significant difference in eradication rates across IV antibiotic duration strategies, despite a diverse array of cultured microorganisms across the studies.

CONCLUSIONS

Although the numbers are small, this systematic review suggests that prolonged IV antibiotic duration, shortened IV antibiotic duration, and shortened IV antibiotic duration supplemented with oral antibiotics confer similar PJI eradication rates after hip or knee arthroplasty.

LEVEL OF EVIDENCE

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

German surgeons' technical preferences for performing total hip arthroplasties: a survey from the National Endoprosthesis Society

PURPOSE

The goal of our study was to conduct an online survey that highlights patterns of practice during total hip arthroplasty (THA).

METHODS

The survey was conducted in June and August 2020. Three hundred thirteen members of the German Society for Endoprosthesis participated in the survey.

RESULTS

The anterolateral approach is by far the most popular approach used for primary total hip arthroplasty, followed by the anterior approach during minimally invasive (55% for the anterolateral and 29% for the anterior) and regular surgery (52% for the anterolateral and 20% for the anterior). Two-thirds of the orthopaedic surgeons do not use drainages during THA. Moreover, 80% of the survey participants routinely apply tranexamic acid during surgery. Surgeons who perform minimally invasive surgery for THA use more frequently fast-track-concepts for post-operative rehabilitation. According to the interviewees, the application of fast-track-concepts leads to reduced periods of hospital stay after THA.

CONCLUSION

Our data demonstrate that patterns of practice during THA in Germany are in line with the evidence provided by current literature. This study can be seen as a stimulus to conduct similar surveys in other countries in order to promote minimally invasive surgery for THA.

Updates in biomaterials of bearing surfaces in total hip arthroplasty

Total hip arthroplasty (THA) is one of the most successful surgical procedures. It entails replacement of the damaged or diseased joint surface with artificial materials. Various materials had been developed and used to achieve optimal outcomes, including longer survivorship and minimal complications. The primary materials used in the manufacture of THA implants are polymers, metal alloys, and ceramics. The failures of THA mainly result from aseptic loosening due to the production of wear particles and the development of periprosthetic joint injection. A lot of advancement and introduction of new biomaterials in THA implants’ armamentarium are designed to avoid the common failure mechanisms and improve the longevity of the implants. In this review, we discussed various aspects of commonly used biomaterials in THA implants, to provide some updated information.

Does Pelvic Orientation Influence Wear Measurement of the Acetabular Cup in Total Hip Arthroplasty—An Experimental Study

Roentgen stereophotogrammetric analysis (RSA) is the gold standard to detect in vivo material wear of the bearing couples in hip arthroplasty. Some surgical planning tools offer the opportunity to detect wear by using standard a.p. radiographs (2Dwear), whilst RSA (3Dwear) needs a special radiological setup. The aims of this study are to prove the interchangeable applicability of a 2Dwear approach next to RSA and to assess the influence of different pelvic positions on measurement outcomes. An implant-bone model was used to mimic three different wear scenarios in seven pelvic-femur alignment positions. RSA and a.p. radiographs of the reference and a follow-up (simulated wear) pose were acquired. Accuracy and precision were worse for the 2Dwear approach (0.206 mm; 0.159 mm) in comparison to the 3Dwear approach (0.043 mm; 0.017 mm). Changing the pelvic position significantly influenced the 2Dwear results (4 of 7, p < 0.05), whilst 3Dwear results showed almost no change. The 3Dwear is superior to the 2Dwear approach, as it is less susceptible to changes in pelvic position. However, the results suggest that a 2Dwear approach may be an alternative method if the wear present is in the range of 100–500 µm and a.p. radiographs are available with the pelvis projected in a neutral position.

The Use of Intraoperative Digital Radiography Alignment Software to Assess Implant Placement in Total Hip Arthroplasty

PURPOSE OF REVIEW

Total hip arthroplasty (THA) is a highly successful surgery with growing rates of utilization in the USA, but surgical outliers leading to postoperative complications remain a concern. There is need for a standard system of accurate, predictable intraoperative evaluation to decrease component positioning outliers. Many current intraoperative imaging systems have shown promise, but there are drawbacks that have led to slow adoption. Digital radiography, in conjunction with Radlink™ technology, is a potential solution to this problem. This review summarizes the clinical application and scientific literature regarding the use of Radlink™ in THA.

RECENT FINDINGS

Traditional surgeon-directed component placement can result in surgical outliers. This is especially true not only among low-volume arthroplasty surgeons, but can also occur with experienced, high-volume surgeons. Digital radiography allows for more precise and accurate placement of the acetabular cup in a targeted range in an effort to improve THA outcomes. Intraoperative images are obtained quickly, and they are accurate when compared to postoperative images. Additionally, the use of Radlink™ results in a significant decrease in leg length and femoral offset outliers. The adoption of Radlink™ technology in THA can significantly decrease surgical outliers, especially errors in acetabular cup placement, leg length, and femoral offset. Digital radiography avoids many of the previous aversions to intraoperative imaging as it produces a fast, reliable image with little radiation exposure and minimal interruption to workflow. There is the potential for Radlink™ use to provide superior patient outcomes, as a decrease in surgical outliers can minimize implant malpositioning with resultant need for revision THAs. Radlink™ may also provide benefit in analyzing other parameters, such as component sizing.

Management strategies for prosthetic joint infection: long-term infection control rates, overall survival rates, functional and quality of life outcomes

DAIR (debridement, antibiotics, and implant retention), one-stage and two-stage revision surgery are the most common management strategies for prosthetic joint infection (PJI) management. Our knowledge concerning their efficacy is based on short to medium-term low-quality studies.

Most studies report infection recurrence rates or infection-free time intervals. However, long-term survival rates of the infection-free joints, functional and quality of life outcome data are of paramount importance.

DAIR, one-stage and two-stage revision strategies are not unique surgical techniques, presenting several variables. Infection control rates for the above strategies vary from 75% to 90%, but comparisons are difficult because different indications and patient selection criteria are used in each strategy.

Recent outcome data show that DAIR and one-stage revision in selected patients (based on host, bacteriological, soft tissue and type of infection criteria) may present improved functional and quality of life outcomes and reduced costs for health systems as compared to those of two-stage revision.

It is expected that health system administrators and providers will apply pressure on surgeons and departments towards the wider use of DAIR and one-stage revision strategies. It is the orthopaedic surgeon’s responsibility to conduct quality studies in order to fully clarify the indications and outcomes of the different revision strategies.

Cite this article: EFORT Open Rev 2021;6:727-734. DOI: 10.1302/2058-5241.6.210008