PHA and EPS production from industrial wastewater by conventional activated sludge, membrane bioreactor and aerobic granular sludge technologies: A comprehensive comparison

The present study has focused on the mainstream integration of polyhydroxyalkanoate (PHA) production with industrial wastewater treatment by exploiting three different technologies all operating in sequencing batch reactors (SBR): conventional activated sludge (AS-SBR), membrane bioreactor (AS-MBR) and aerobic granular sludge (AGS). A full aerobic feast/famine strategy was adopted to obtain enrichment of biomass with PHA-storing bacteria. All the systems were operated at different organic loading (OLR) rate equal to 1-2-3 kgCOD/m3∙d in three respective experimental periods. The AS-MBR showed the better and stable carbon removal performance, whereas the effluent quality of the AS-SBR and AGS deteriorated at high OLR. Biomass enrichment with PHA-storing bacteria was successfully obtained in all the systems. The AS-MBR improved the PHA productivity with increasing OLR (max 35% w/w), whereas the AS-SBR reduced the PHA content (max 20% w/w) above an OLR threshold of 2 kgCOD/m3∙d. In contrast, in the AGS the increase of OLR resulted in a significant decrease in PHA productivity (max 14% w/w) and a concomitant increase of extracellular polymers (EPS) production (max 75% w/w). Results demonstrated that organic carbon was mainly driven towards the intracellular storage pathway in the AS-SBR (max yield 51%) and MBR (max yield 61%), whereas additional stressors in AGS (e.g., hydraulic selection pressure, shear forces) induced bacteria to channel the COD into extracellular storage compounds (max yield 50%) necessary to maintain the granule's structure. The results of the present study indicated that full-aerobic feast/famine strategy was more suitable for flocculent sludge-based technologies, although biofilm-like systems could open new scenarios for other biopolymers recovery (e.g., EPS). Moreover, the AS-MBR resulted the most suitable technology for the integration of PHA production in a mainstream industrial wastewater treatment plant, considering the greater process stability and the potential reclamation of the treated wastewater.

Infrapatellar branch of the saphenous nerve lesion following tibial nailing: it is possible to avoid it?

BACKGROUND

Iatrogenic injury to the infrapatellar branches of saphenous nerve is a common complication following tibial nailing. This lesion seems to be directly related to the surgical approach adopted for nail insertion. The aim of the present study was to systematically review the current literature in order to assess the eventual superiority of one surgical approach for tibial nailing over the others in limiting the neurological impairment related to infrapatellar branch injury.

MATERIALS AND METHODS

The available literature was systematically screened searching papers dealing with iatrogenic injury to the infrapatellar branch of saphenous nerve after intramedullary tibial nailing. The terms "Saphenous" and "Infrapatellar branch" were used in combination with "intramedullary nailing" and "tibial fractures", supplying no limits regarding the publication year. Only publications in English were considered. Case reports, technical notes, instructional course, literature reviews, biomechanical and/ or in vitro studies were all excluded. Coleman methodological score was performed in all the retained articles.

RESULTS

Four articles matched the inclusion criteria. There were one original article and three retrospective study. Hypoesthesia and a larger extension of the area of sensory-loss were more frequently observed after vertical incision approach in three out of four articles. A trend towards a lower rate of iatrogenic nerve damage using a transverse incision was found in the remaining one, without any statistical significance.

CONCLUSIONS

In order to avoid infrapatellar nerve lesion, horizontal or oblique incisions or percutaneous approaches should be favored, although in some cases a longitudinal incision is required. Limited-extension incisions could minimize the risk and the incidence of this complication.

Hip-spine relationship: clinical evidence and biomechanical issues

The hip-spine relationship is a critical consideration in total hip arthroplasty (THA) procedures. While THA is generally successful in patient, complications such as instability and dislocation can arise. These issues are significantly influenced by the alignment of implant components and the overall balance of the spine and pelvis, known as spinopelvic balance. Patients with alteration of those parameters, in particular rigid spines, often due to fusion surgery, face a higher risk of THA complications, with an emphasis on complications in instability, impingement and dislocation. For these reasons, over the years, computer modelling and simulation techniques have been developed to support clinicians in the different steps of surgery. The aim of the current review is to present current knowledge on hip-spine relationship to serve as a common platform of discussion among clinicians and engineers. The offered overview aims to update the reader on the main critical aspects of the issue, from both a theoretical and practical perspective, and to be a valuable introductory tool for those approaching this problem for the first time.

Are there gender-specific differences in hip and knee cartilage composition and degeneration? A systematic literature review

The aim of the present review is to systematically analyse the current literature about gender differences in hip or knee cartilage composition and degeneration, to help explaining how and why osteoarthritis affects women more often and more severely than men. A systematic review of the literature in English was performed. Eleven studies on 1962 patients (905 females and 787 males) that reported differences on cartilage composition between males and females were included. Nine evaluated the knee, one the hip, and one both. They were heterogeneous in their methods: one conducted histological analyses, and all the others evaluated cartilage characteristics (volume, width, and composition) through magnetic resonance imaging. All authors reported gender differences in both volume and morphology of the cartilage, from infancy to menopause. In fact, a study on 92 healthy children statistically showed significant gender differences in cartilage thickness at all sites, even after adjustment for age, body, and bone size. Gender differences become more evident after menopause, when women have a lower cartilage volume and a higher cartilage loss. Men show significantly higher knee and hip cartilage volumes than women, and women carry a significantly greater risk to develop osteoarthritis. This is in part due to body and bone size, but also depends on qualitative and quantitative differences in the composition of cartilage and its degeneration rate after menopause. Structural changes in cartilage that occur between genders during ageing have significance in the development of osteoarthritis.

High three-dimensional accuracy of component placement and lower limb alignment using a robotic arm-assisted system and gap-balancing instrument in total knee arthroplasty

PURPOSE

It was hypothesized that robotic arm-assisted total knee arthroplasty (RA-TKA) using additionally a gap-balancing instrumentation will show high accuracy in executing the planning in femoral and tibial component placement throughout the range of knee motion (ROM) during TKA surgery.

METHODS

Prospectively collected data were analysed for patients undergoing RA-TKA. A cruciate retaining cemented design was implanted using the MAKO® robotic system. Lower limb alignment at 0°, 30°, 45°, 60° and 90° of flexion was recorded at the beginning of surgery and finally after implantation of the components. A ligament tensioner was inserted after tibial precut to measure the extension and flexion gap, and final component placement was planned based on 3D CT images. Femoral and tibial component placement was measured in all three planes.

RESULTS

A total of 104 patients were included (mean age 69.4 ± 9 years; 44 male, 60 female). The difference in component placement after planning and final implantation showed less valgus of 0.7° ± 1.4° (p < 0.001), less external rotation of 0.6° ± 1.9° (p = 0.001) and less flexion of 0.9° ± 1.8° (p < 0.001) for the femoral component. The tibial component was placed in more varus of 0.2° ± 0.9° (p = 0.056) and more posterior slope of 0.5° ± 0.9° (p < 0.001). The lower limb alignment in extension was 4.4° ± 5.2° of varus of the native knee and changed to 1.2° ± 1.9° of varus after TKA (p < 0.01).

CONCLUSION

Robotic-assisted TKA helps to achieve the target of alignment and component placement very close to the planning. It allows optimal component placement of off-the-shelf implants respecting patient's specific anatomy.

LEVEL OF EVIDENCE

Level II.

Long-term survival and complication rate of cementless prosthetic stems in primary total hip arthroplasty categorized by types according to Mont classification: a regional registry-based study on 53,626 implants

INTRODUCTION

The purpose of this retrospective registry-based study is to assess survival and causes of failure of cementless stem implants used in total hip arthroplasty (THAs), to ascertain if there are differences when these are categorized according to the six types described by Mont.

METHODS

Data collected from the regional registry regarding all primary THAs performed from 2000 to 2019 were analyzed. Femoral prosthetic stems were divided into the six types of Mont classification. For each stem type, number of implants, survival and causes of failure were evaluated and compared.

RESULTS

The most frequently implanted stem type was the 3c type (53.4%). Type 1 had the lowest stem failure rate (1.6%), and type 6 showed the highest (3.9%). Periprosthetic fracture was the most frequent complication in type 6, accounting for 34.5% of failures. Aseptic loosening was the main complication in type 2 stems, accounting for 36.4% of failures. Pairwise comparisons showed significant higher survival of type 1 compared to type 3c (p = 0.000026) and type 6 (p = 0.000076), and between type 3a compared to type 3c (p = 0.03) and type 6 (p = 0.026).

CONCLUSION

Significant variations in implant survival rates were found among the six Mont-types of cementless stems. These findings emphasize the paramount importance of stem design and fixation area in determining long-term survival, providing a guidance for orthopedic surgeons in the selection of the most appropriate stem for primary THA, contributing to our understanding of cementless stem performance, presenting invaluable insights to further improve patient outcomes in THA surgery.

The Medium- to Long-Term Results of Vascular-Sparing Subcapital Osteotomy (VASSCO) for Pediatric Patients with Chronic Slipped Capital Femoral Epiphysis

Background: In patients affected by chronic slipped capital femoral epiphysis (C-SCFE), the performance of a subcapital osteotomy is an effective procedure to correct the deformity at the proximal femur. However, the rate of postoperative complications is very high, with iatrogenic avascular necrosis of the femoral head (AVN) being the most bothersome. To overcome the risk of AVN, the modified Dunn procedure according to Ganz and, more recently, the Vascular Sparing Subcapital Osteotomy (VASSCO) technique have been proposed; however, only short-term follow-up studies are available on the latter technique being used. The aim of this study is therefore to show our mid-term clinical and radiological results with the VASSCO technique. Materials and Methods: A total of 26 patients underwent VASSCO for moderate or severe stable C-SCFE between 2012 and April 2016 with an average 10-year follow-up (range 8-12 years). The outcomes was evaluated using the HHS and pre- and postoperative ROM. The radiological outcomes and complications were collected. Results: No major intraoperative complications occurred; three patients reported postoperative transient apraxia of the lateral femoral cutaneous nerve, which completely recovered in six months. All the radiological outcomes showed substantial improvement postoperatively. One case patient developed AVN of the femoral head and required a total hip arthroplasty after 12 years. Conclusions: The current data suggest that VASSCO osteotomy is a reliable technique with very good clinical results at mid-term follow-up; it could be considered a valuable alternative to using more complex techniques to restore the proximal femoral anatomy in moderate to severe C-SCFE.

Combined recovery of polyhydroxyalkanoates and reclaimed water in the mainstream of a WWTP for agro-food industrial wastewater valorisation by membrane bioreactor technology

The present study investigated the combined production of reclaimed water for reuse purposes and polyhydroxyalkanoates (PHA) from an agro-food industrial wastewater. A pilot plant implementing a two-stage process for PHA production was studied. It consisted of a mainstream sequencing batch membrane bioreactor (SBMBR) in which selection of PHA-accumulating organisms and wastewater treatment were carried out in, and a side-stream fed-batch reactor (FBR) where the excess sludge from the SBMBR was used for PHA accumulation. The performance of the SBMBR was compared with that of a conventional sequencing batch reactor (SBR) treating the same wastewater under different food to microorganisms' ratios (F/M) ranging between 0.125 and 0.650 kgCOD kgTSS-3 d-1. The SBMBR enabled to obtain very high-quality effluent in compliance with the relevant national (Italy) and European regulations (Italian DM 185/03 and EU, 2020/741) in the field of wastewater reclamation, whereas the performances in the SBR collapsed at F/M higher than 0.50 kgCOD kgTSS-1d-1. A maximum intracellular storage of 45% (w/w) and a production yield of 0.63 gPHA L-1h-1 were achieved when the SBMBR system was operated with a F/M ratio close to 0.50 kgCOD kgTSS-1d-1. This resulted approximately 35% higher than those observed in the SBR, since the ultrafiltration membrane avoided the washout of dispersed and filamentous bacteria capable of storing PHA. Furthermore, while maximizing PHA productivity in conventional SBR systems led to process dysfunctions, in the SBMBR system it helped mitigate these issues by reducing membrane fouling behaviour. The results of this study supported the possibility to achieve combined recovery of reclaimed water and high-value added bioproducts using membrane technology, leading the way for agro-food industrial wastewater valorization in the frame of a circular economy model.

Inflammatory Biomarkers and Gait Impairment in Older Adults: A Systematic Review

Peripheral inflammation and gait speed alterations are common in several neurological disorders and in the aging process, but the association between the two is not well established. The aim of this systematic literary review is to determine whether proinflammatory markers are a positive predictor for gait impairments and their complications, such as falls in older adults, and may represent a risk factor for slow gait speed and its complications. The systematic review was performed in line with the Preferred Report Items for Systematic Review and Meta-Analyses (PRISMA). A protocol for literature searches was structured a priori and designed according to the International Perspective Register of Systemic Review (PROSPERO: CRD42023451108). Peer-reviewed original articles were identified by searching seven electronic databases: Excerpta Medica Database (EMBASE), SciVerse (ScienceDirect), Scopus, PubMed, Medline, Web of Science, and the Cochrane Library. The search strategy was formulated based on a combination of controlled descriptors and/or keywords related to the topic and a manual search was conducted of the reference lists from the initially selected studies to identify other eligible studies. The studies were thoroughly screened using the following inclusion criteria: older adults, spatiotemporal gait characteristics, and proinflammatory markers. A meta-analysis was not performed due to the heterogeneity of the studies, and the results were narratively synthesized. Due to the clinical and methodological heterogeneity, the studies were combined in a narrative synthesis, grouped by the type of biomarkers evaluated. A standardized data extraction form was used to collect the following methodological outcome variables from each of the included studies: author, year, population, age, sample size, spatiotemporal gait parameters such as gait velocity, and proinflammatory markers such as TNF-α, high sensitivity C-reactive (CRP) proteins, and IL-6. We included 21 out of 51 studies in our review, which examined the association between inflammatory biomarkers and gait impairment. This review highlights the role of TNF-α, CRP, and IL-6 in gait impairment. Biomarkers play an important role in the decision-making process, and IL-6 can be an effective biomarker in establishing the diagnosis of slow gait speed. Further longitudinal research is needed to establish the use of molecular biomarkers in monitoring gait impairment.

Cementless Primary Stems in Revision Hip Arthroplasty: A Narrative Review

Cementless primary stems in revision hip arthroplasties may be conservative options to preserve bone stock and provide adequate reconstruction of the hip biomechanics. However, there is still little evidence about indications, limitations, and outcomes. This narrative review showed that conventional standard stems were adopted in different revision settings, up to Paprosky IIIA grade bone defects. In cases of acceptable metaphyseal bone stock, when a scratch fit of at least 4 cm can be achieved, a conventional cementless stem may be an adequate solution. Mid-term clinical and radiographic outcomes and survival rates were similar to long revision stems, whereas complications, surgical time, and costs were lower among conventional stems. However, unsuitable contexts for conventional stems included canal diameters larger than 18 mm and failed revision stems with cortical weakening. Even short stems can be considered in revisions, in order to preserve bone stock and stay proximal to femoral remodeling zones and bone/cement plugs. Short stems were successfully adopted up to Paprosky IIIA bone defects, achieving mid-term survival rates not inferior to long revision stems. Ageing, osteoporosis, and intraoperative femoral fractures were the main negative prognostic factors. In very select cases, a downsizing technique (from longer to shorter stems) may be adopted to simplify the procedure and reduce complications.

Direct Anterior Approach in Total Hip Arthroplasty for Severe Crowe IV Dysplasia: Retrospective Clinical and Radiological Study

Background and Objectives: total hip arthroplasty (THA) for Crowe IV hip dysplasia poses challenges due to severe leg shortening, muscle retraction and bone stock issues, leading to an increased neurological complication, and revision rate. The direct anterior approach (DAA) is used for minimally invasive THA but its role in Crowe IV dysplasia is unclear. This retrospective study examines if DAA effectively restores hip biomechanics in Crowe IV dysplasia patients with <4 cm leg length discrepancy, managing soft tissue and yielding functional improvement, limb length correction, and limited complications. Materials and Methods: 19 patients with unilateral Crowe IV hip osteoarthritis and <4 cm leg length discrepancy undergoing DAA THA were reviewed. Surgery involved gradual soft tissue release, precise acetabular cup positioning, and stem placement without femoral osteotomy. Results: results were evaluated clinically and radiographically, with complications recorded. Follow-up revealed significant Harris Hip Score and limb length discrepancy improvements. Abductor muscle insufficiency was present in 21%. The acetabular component was accurately placed, centralizing the prosthetic joint's rotation. Complications occurred in 16% of cases, including fractures, nerve issues, and infection. DAA in THA showcased positive outcomes for hip function, limb length, and biomechanics in Crowe IV dysplasia. Conclusions: the technique enabled accurate cup positioning and rotation center adjustment. Complications were managed well without implant revisions. DAA is a viable option for Crowe IV dysplasia, restoring hip function, biomechanics, and reducing limb length discrepancy. Larger, longer studies are needed for validation.

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

BACKGROUND

Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.

METHODS

This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.

RESULTS

The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (β coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.

CONCLUSION

Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely.

Surgical approach to correction of severe knee malalignment in a pediatric population in Tanzania

AIM

Severe knee malalignment in children usually needs surgery with different options available in surgical approaches. The aim of this study was to report the results of the surgical correction of severe knee malalignment in children treated with femoral and tibial osteotomy, temporarily fixed with percutaneous Kirschner wires, in a low- and middle-income country (LMIC), with limited medical resources.

Chronological Changes in Sagittal Femoral Bowing after Primary Cementless Total Hip Arthroplasty: A Comparative 3D CT Study

Little is known about dynamic changes of femoral anatomy after total hip arthroplasty (THA), in particular about sagittal femoral bowing (SFB). A 3D CT study was designed to evaluate the chronological changes of SFB after cementless femoral stem implantation for primary THA. Ten patients who underwent unilateral primary THA with a cementless femoral stem, with 2 consecutive CT scans (extending from the fourth lumbar vertebra to the tibial plateaus), performed before THA and at least 3 years after THA, were enrolled. The 3D models of femurs were created using image segmentation software. Using the two CT scans, SFB values of the proximal and middle thirds were calculated on the replaced and untreated sides by two different observers. Eight anatomical stems and two conical stems were involved. The post-operative CT was performed at an average follow-up of 6.5 years after THA (range: 3-12.5). The measurements performed by the two observers did not differ in the proximal and middle regions. A significant difference between the pre-operative and post-operative SFB compared to the untreated side was found in the proximal femur segment (p = 0.004). Use of a cementless stem in THA induced chronological changes in SFB of the proximal femur, after a minimum timespan of 3 years.

Comparison of single taper and dual taper versions of the same stem design in total hip arthroplasty for primary osteoarthritis

BACKGROUND

In total hip arthroplasty (THA), the outcomes of single taper (ST) and dual taper (DT) versions of the same stem design have been scarcely studied. A registry study comparing ST and DT versions of the same stem design was designed, aiming to assess: (1) the survival rates and the hazard ratios for failure; (2) the survival rates and the hazard ratios for failure using stem-focused endpoints.

MATERIAL AND METHODS

A regional arthroplasty registry was interrogated about stem designs with ST and DT versions in cementless THAs performed for primary osteoarthritis. Only the same cup and ceramic-on-ceramic bearings were included: the DT stems had a titanium-on-titanium modularity. Demographic and implant features were recorded. Survival rates and hazard ratios were evaluated and compared. Stem-focused endpoints were also investigated.

RESULTS

A total of 5359 THAs were included, with three stem designs. The two versions of every stem showed different demographics and implant-related features: ST versions were preferentially implanted in heavier young men. For each stem, the two versions had similar survival rates at 5 years (p = 0.076; p = 0.319; p = 0.616) and similar adjusted hazard ratios for failures (p = 0.084; p = 0.308; p = 0.729). When stem-focused endpoints were adopted, the ST and DT versions of the three stems achieved similar survival rates (p = 0.710; p = 0.784; p = 0.983) and similar adjusted hazard ratios (p = 0.647; p = 0.858; p = 0.787). Three neck breakages occurred (0.0007% of all the modular implants).

CONCLUSIONS

ST and DT versions of the same stem design did not show any differences in terms of survival rates and hazard ratios for failures at 5 years.

LEVEL OF EVIDENCE

IV.

Single-taper conical tapered stem in total hip arthroplasty for developmental dysplasia of the hip: A long-term evaluation

INTRODUCTION

Conical tapered stems may be useful implants to manage the reconstruction of complex dysplastic anatomies. The aims of this paper were to assess: 1) the preoperative CT features of the dysplastic femurs; 2) survival rates, complications and reasons for revision; 3) the clinical outcomes; 4) the radiographic outcomes of single-taper conical stems in dysplasia (defined as center edge angle < 20°) at a long-term follow-up.

HYPOTHESIS

Monoblock conical stem provides a 10-year survival rate of at least 95%, with excellent clinical outcomes and bony ingrowth.

MATERIALS AND METHODS

In total, 100 THAs in 85 patients (15 bilateral cases) were enrolled. The average age of the patients at surgery was 50.9±11.5 years. Assessment of the native femoral morphology was performed using CT-scan, coronal (neck-shaft angle, offset, center of rotation position) and axial parameters (anteversion, mediolateral and anteroposterior femoral diameters). Clinical (HHS score) and radiological (osseointegration, subsidence and offset reconstruction) outcomes were evaluated at the last available follow-up.

RESULTS

The mean follow-up was 9.34±5.61 years. Severely distorted anatomies from Crowe I to Crowe IV were included, with a mean canal flare of 4.3 and a mean femoral antetorsion of 34°. The survival rates were stable at long-term (98.9% at 10 and 15 years): no aseptic loosening occurred. The mean postoperative HHS was 89.8±6.8 points. Ninety-nine percent of the stems showed bone ingrowth, from 6 months to the last available follow-up. Subsidence occurred in 18% of the cases (mean value: 2.5mm, range: 1-6mm) in the first month, with subsequent stabilization. A mild proximal stress shielding occurred in 28% of the THAs. Radiolucent lines were detected in the 8% of the cases. There was a postoperative loss of offset in 12% of the cases.

DISCUSSION

Conical stems in dysplastic hips achieved bony ingrowth at long-term outcome, even in complex anatomies. Subsidence, proximal stress shielding and imperfect offset restoration may occur with this implant.

LEVEL OF PROOF

IV; retrospective study.

Higher failure rate of secondary patellar resurfacing following bicompartmental knee arthroplasty

INTRODUCTION

The role of secondary patellar resurfacing (SPR) in anterior knee pain (AKP) is still debated in literature. A regional arthroplasty registry was investigated, aiming to: (1) assess the survival rate of SPR; and (2) compare SPR to tricompartmental TKA.

MATERIALS AND METHODS

The regional arthroplasty registry RIPO was investigated about all SPRs performed after bicompartmental arthroplasty. The survival rates and the reasons for revision were assessed as any other factor that could have influenced implants failure. SPR survivorship was compared to tricompartmental TKAs.

RESULTS

406 SPRs performed after bicompartmental arthroplasty were analyzed. The survival rates were 80.6% (CI 95% 75.9-84.5) at 5 years and 77.6% (CI 95% 72.4-82) at 7 years. Half of the SPRs was performed 0.9-2.4 years after the index bicompartmental arthroplasty. SPR achieved lower survival than tricompartmental TKA (80.6% vs 96.7%, p < 0.001), with an adjusted hazard ratio for failure of 5.5 (CI 95% 4.2-7.1, p < 0.001). SPRs performed within 2 years after primary implant had a significantly higher rates of failure when compared to tricompartmental TKA (HR: 6.4, CI 95% 4.8-8.4, p < 0.001).

CONCLUSION

SPR after bicompartmental knee arthroplasty showed modest 5- and 7-year survival rates, worse than primary tricompartmental TKA. When SPRs are performed within 2 years after primary arthroplasty, a significant higher risk of failure should be expected, highlighting than appropriate pre-operative work-up and patient selection is crucial for SPR successful outcome.

LEVEL OF EVIDENCE

III, therapeutic study.

Isolated Femoral or Tibial Component Revision in Total Knee Arthroplasty: A Systematic Review

OBJECTIVE

The purpose of this systematic review is to assess clinical and radiographic outcomes, complications rates, rates and reasons of re-revision of isolated femoral or tibial component revisions, comparing them with total knee revisions.

METHODS

A review of the published literature was performed using Medline, Embase and Cochrane libraries. The terms "isolate" and "revision" and "knee arthroplasty" or "knee replacement" were together used as MESH terms. Partial knee replacement, non-English literature, case reports and papers published before 2000 were excluded.

RESULTS

Out of 911 papers, six papers met the inclusion criteria. Mean MINORS scores achieved quite low values (13.33 and 13.67). No study encompassed revisions for septic loosening or infection. Total revisions performed for instability and wear achieved better clinical outcomes: in the other cases, partial and total revisions showed no differences in clinical outcomes. Both the cohorts showed similar radiographic features. Lesser bleeding and shorter operative times were observed in partial revisions compared to total revisions. The re-revision rates were similar in most of comparative studies: only one study noticed a significant difference in the failure rate between partial (25% at 3 years) and full (7% at 3.5 years) revisions.

CONCLUSIONS

The poor quality of the studies precluded sound conclusions. Isolated tibial or femoral component revision is an option when the other component is well-fixed and positioned and in absence of chronic periprosthetic infection; nevertheless, it should be carefully evaluated when the reasons for revision are wear or instability.

Total Knee Arthroplasty (TKA): When Do the Risks of TKA Overcome the Benefits? Double Risk of Failure in Patients up to 65 Years Old

OBJECTIVE

The aim of this study was to document the survival rate in the middle-aged patient group up to 65 years old and to compare it with other age groups of patients undergoing total knee arthroplasty (TKA) for knee osteoarthritis (OA).

DESIGN

The Register of Orthopaedic Prosthetic Implants (RIPO) regional registry was used to analyze the results of patients <80 years old affected by primary OA and treated with TKA from 2000 to 2019. The database was investigated according to the age group: younger than 50 years, 50-65 years, or 66-79 years, with the aim to estimate revision surgeries and implant survivorship.

RESULTS

A total of 45,488 TKAs for primary OA were included in the analysis (M: 11,388; F: 27,846). The percentage of patients <65 years old increased from 13.5% to 24.8% between 2000 and 2019 (P < 0.0001). The survival analysis showed an overall influence of age on the implant revision rate (P < 0.0001), with an estimated survival rate of 78.7%, 89.4%, and 94.8% at 15 years in the 3 groups, respectively. Compared with the older-aged group, the relative risk of failure was 3.1 (95% confidence interval [CI] = 2.2-4.3; P < 0.001) higher in patients <50 years old and 1.8 (95% CI = 1.6-2.0; P < 0.001) higher in patients 50-65 years old.

CONCLUSIONS

TKA use in the middle-aged patient population up to 65 years old increased significantly over time. These patients present a double risk of failure with respect to older patients. This is particularly important considering the increasing life expectancy and the emergence of new joint preserving strategies, which could postpone the need for TKA to an older age.

Titanium modular stems in total hip arthroplasty due to developmental dysplasia: a registry comparison with single-taper implants

INTRODUCTION

The routine use of proximal femoral modularity was discouraged in total hip arthroplasties (THAs). However, titanium dual-taper (DT) implants may provide some advantages over single-taper (ST) stems in cases of complex deformity. A registry study comparing ST and DT stems in dysplasia was designed, aiming to assess: (1) survival rates at long-term; (2) reasons for revision; (3) the profile of failed implants.

METHODS

The arthroplasty registry RIPO was investigated for cementless THAs performed for dysplasia since 2000. ST implants were compared to titanium-on-titanium DT stems. Demographics and implant features were collected. Survival rates and reasons for revision were compared. The profile of DT stem failures in dysplasia was defined.

RESULTS

6429 implants were included in the study, 3642 ST and 2787 DT. The demographic and implant features of the 2 cohorts were not comparable. The DT cohort achieved higher survival rates at long-term (93.9% vs. 91.6%, p = 0.018). DT implants showed a higher rate of implant breakage (0.6%, p = 0.011) and a lower rate of aseptic loosening (p = 0.005). There were no differences in terms of revisions for dislocation. No metallosis occurred. There were more revisions in DT implants in males <65 years, with a 28-mm head size or smaller.

CONCLUSIONS

Modularity did not result in lower survival rates in dysplastic patients and may even reduce the rate of aseptic loosening in comparison to ST stems. The rate of implant breakage is not negligible. Younger males are not good candidates for titanium DT stems.

Mid-term outcomes of revision hip arthroplasty due to titanium modular neck failure

INTRODUCTION

The current strategy for modular neck failures in total hip arthroplasty (THA) is calibrated on CrCo neck failures. Stem revision is usually required, but the procedure is challenging and achieves modest outcomes (up to 20% of re-revisions at short-term). No study reports revision strategies and outcomes after Ti neck failures. Aims of the study were to evaluate: (1) demographic and implant features of the cohort to be revised, (2) intra-operative findings and surgical revision strategies and (3) clinical and radiological post-revision outcomes.

MATERIALS AND METHODS

Hospital database was enquired about revisions due to Ti neck failures in primary THAs. Sixty-five revisions were enrolled (all with the same modular system). Neck exchange was attempted as the first-line treatment. Patients were clinically and radiographically evaluated after revision.

RESULTS

The revision cohort encompassed fatigue neck fractures occurred 4.4 ± 2.6 years after THA: patients < 65 years and/or > 80 kg (98.5%) were predominant. Fifty-three neck exchanges were performed (81.5%). Eleven failures required stem revisions (16.9%), generally due to demanding neck extraction. Six complications occurred after neck exchange (11.3%), among them 2 acute infections requiring surgery (3.8%). Among stem revisions, one aseptic loosening and one neck re-fracture (18.5%) required re-revisions. At a mean follow-up of 7.1 ± 4 years, the neck exchange cohort achieved a mean HHS of 89.1 ± 6.3 (stem revisions: 84.1 ± 10.9).

CONCLUSIONS

Revisions for Ti neck failures were predominantly performed due to fatigue fractures. In case of failures, neck exchange is a feasible procedure in most of the cases, with good outcomes at 7 years.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Revision Hip Arthroplasty Using a Modular Head-Neck Adapter System and a Ceramic Head: 5-Year Clinical and Radiographic Outcomes

INTRODUCTION

A modular head-neck adapter system may help surgeons restore the proximal hip biomechanics in revision hip arthroplasty. However, the clinical and radiographic 5-year outcomes of the system are still scarcely reported. The aim of this study is the assessment of (1) complications and survival rates, (2) clinical and (3) radiological outcomes of the modular head-neck adapter system with a ceramic head in revision hip arthroplasty at 5 years.

METHODS

32 revision hip arthroplasties using a modular head-neck adapter system and a ceramic head were retrospectively recorded. Preoperative demographic and implant features were collected. Clinical and radiographic outcomes, failures and reasons for re-revisions were recorded at the last follow-up.

RESULTS

A mean follow-up of 59.8 ± 26 months was achieved. The survival rate was 90.6% at 5 years. Post-operative complications occurred in nine cases (28.1%): two dislocations (6.2%), one aseptic cup loosening (3.1%) requiring re-revision, one (3.1%) persistent pelvic pseudotumor requiring embolization. No mechanical failures of the adapter or ceramic head occurred. The mean post-operative HHS score was 84.4 points. Thirteen cases (40.6%) showed optimal radiographic cup osseointegration, and 17 hips (53.1%) showed valid stem osseointegration. The mean post-operative femoral offset was 48.84 mm, larger than the contralateral side (p = 0.02). The post-operative lateralization of the hip joint was 38.09 mm, close to the contralateral side (p = 0.4).

CONCLUSIONS

In revisions, the modular head-neck adapter system with ceramic head provided good clinical outcomes and acceptable radiographic reconstruction of hip biomechanics, with a survival rate of 87.9% at 5 years.

The Potential Role of Gut Bacteriome Dysbiosis as a Leading Cause of Periprosthetic Infection: A Comprehensive Literature Review

(1) Background: Periprosthetic joint infections (PJIs) represent a small yet important risk when undertaking a joint arthroplasty; they occur in approximately 1-2% of treatments. These infections create a medical and financial burden for patients and healthcare systems. Despite the introduction of recognized best clinical practices during arthroplasty operations, it is not yet possible to further reduce the risk of infection after surgery. The purpose of this review is to raise awareness of the potential role of gut dysbiosis in the development of PJIs and to highlight the potential of the gut bacteriome as a possible target for preventing them. (2) Methods: We compiled all the available data from five databases, examining the effects of gut dysbiosis in human and murine studies, following PRISMA guidelines, for a total of five reviewed studies. (3) Results: One human and one murine study found the Trojan horse theory applicable. Additionally, inflammatory bowel diseases, gut permeability, and oral antibiotic ingestion all appeared to play a role in promoting gut dysbiosis to cause PJIs, according to the other three studies. (4) Conclusions: Gut dysbiosis is linked to an increased risk of PJI.

ACL surgery: reasons for failure and management

Despite the general success of anterior cruciate ligament reconstructions (ACL-R), there are still studies reporting a high failure rate. Orthopedic surgeons are therefore increasingly confronted with the treatment of ACL retears, which are often accompanied by other lesions, such as meniscus tears and cartilage damage and which, if overlooked, can lead to poor postoperative clinical outcomes. The literature shows a wide variety of causes for ACL-R failure. Main causes are further trauma and possible technical errors during surgery, among which the position of the femoral tunnel is thought to be one of the most important. A successful postoperative outcome after ACL-revision surgery requires good preoperative planning, including a thorough evaluation of patient's medical history, e.g. instability during daily or sports activity, increased general joint laxity, and hints for a low-grade infection. A careful clinical examination should be performed. Additionally, comprehensive imaging is necessary. Besides a magnetic resonance imaging, a CT scan is helpful to determine location of tunnel apertures and to analyze for tunnel enlargement. A lateral knee radiograph is helpful to determine the tibial slope. The range of surgical options for the treatment of ACL-R failure is broad today. Orthopedic surgeons and experts in Sports Medicine must deal with various possible associated injuries of the knee or unfavorable anatomical conditions for ACL-R. The aim of this review was to highlight predictors and reasons of failures of ACL-R as well as describe diagnostic procedures to individualize treatment strategies for improved outcome after revision ACL-R.

Patient Reported Outcome Measures (PROMs) in Surgery: Evaluation after Minimally Invasive Reduction and Percutaneous K-Wires Fixation for Intra-Articular Calcaneal Fractures

Background: The optimal surgical treatment of intra-articular calcaneal fractures (IACF) is still under debate. In the literature, results are based on clinical or radiographical findings. Few studies have evaluated the effect of patient expectations on patient-reported outcomes after surgery and little is known about outcomes directly reported by the patient who experienced it. Patient reported outcome measures (PROMs) may represent a viable and useful tool for evaluating the efficacy of the procedure and can be considered as an indicators of health-care quality. The aim of this study is to evaluate PROMs after minimally invasive reduction and percutaneous Kirschner-wires fixation for IACF, and to compare PROMs to pre-operative and last follow-up radiographic findings. Methods: 33 consecutive patients with IACF treated with minimally invasive reduction and percutaneous K-wires fixation were included. Data collection included demographics, pre-operative and last available Böhler and Gissane angle X-rays, foot function index (FFI), and foot and ankle outcome score (FAOS). Results: At a mean follow up of 36.7 months, the mean FFI score was 24.3 ± 19.9 and the mean FAOS score was 68 ± 24.8. Patients with better Gissane angle showed better activity limitations FFI subscores. Moreover, worse pre-operative Gissane and Böhler angle were significantly associated with a worse total FAOS score and subscores. Conclusions: Minimally invasive reduction and percutaneous K-wires fixation provided satisfactory PROMs. Despite these results, prospective randomized studies are required to confirm the validity and reliability of PROMs in evaluating different treatments.

One-stage complete eradication and revision hip due to pseudotumor in metal-on-metal hip arthroplasty

Background

The correct management and treatment of pseudotumors due to metal-on-metal (MOM) hip arthroplasty are still debated. The purpose of this study is to analyze the surgical treatment and the clinical and radiographic 3-year outcomes of MOM arthroplasty revisions due to pseudotumor treated with a strategy of excision and revision.

Methods

Consecutive, retrospective series of 21 patients (8 males/13 females) with pseudotumor due to MOM hip arthroplasty was surgically treated at a single tertiary center. Demographic, clinical, radiological and implant-related features were collected pre-operatively. Post-revision clinical and radiographic parameters were evaluated. Chromium (Cr) and cobalt (Co) blood samples were collected before and after surgery.

Results

Three patients (14.2%) with pseudotumor underwent a resection arthroplasty due to infection (perioperative finding) and could not be reimplanted due to septic relapses. Twenty (95.2%) pseudotumors were completely resected. Revisions [2 total hip reimplantations (11.1%) and 16 isolated component revisions (88.9%)] were performed with non-MOM couplings. A clinical improvement at a mean post-revision follow-up 3.3 years [standard deviation (SD), ±2.2 years] was observed, from 50.3 (SD, ±4.6) to 88.3 (SD, ±9.2) Harris hip score (HHS) points (P<0.001). Among revisions, there were 5 complications (23.8%): 1 dislocation, 1 psoas impingement, and 3 infections (14.2%). No re-revision was carried out. Three (14.2%) pseudotumors recurred: 1 was surgically treated, 1 was treated with selective arterial embolization, and 1 clinically followed. At the final follow-up, Cr and Co blood ions beyond the threshold decreased from 85.7% cases to 0% in the seven patients that could be evaluated.

Conclusions

The one-stage strategy of radical excision and revision with non-MOM couplings in pseudotumors due to MOM hip arthroplasty achieved good 3-year outcomes. However, complications were frequent (23%). Recurrences were not rare (14%) and did not require implant re-revision.

Hip Labral Morphological Changes in Patients with Femoroacetabular Impingement Speed Up the Onset of Early Osteoarthritis

Over the last decade, evidence has mounted for a prominent etiologic role of femoroacetabular impingement (FAI) in the development of early hip osteoarthritis (OA). The aim of this study was to compare the ultrastructure and tissue composition of the hip labrum in healthy and pathological conditions, as FAI and OA, to provide understanding of structural changes which might be helpful in the future to design targeted therapies and improve treatment indications. We analyzed labral tissue samples from five healthy multi-organ donors (MCDs) (median age, 38 years), five FAI patients (median age, 37 years) and five late-stage OA patients undergoing total hip replacement (median age, 56 years). We evaluated morpho-functional by histology and transmission electron microscopy. Extracellular matrix (ECM) structure changes were similar in specimens from FAI compared to those from patients with OA (more severe in the latter) showing disorganization of collagen fibers and increased proteoglycan content. In FAI and in OA nuclei the chromatin was condensed, organelle degenerated and cytoplasm vacuolized. Areas of calcification were mainly observed in FAI and OA labrum, as well as apoptotic-like features. We showed that labral tissue of patients with FAI had similar pathological alterations of tissue obtained from OA patients, suggesting that FAI patients might have high susceptibility to develop OA.

Using Wearable Inertial Sensors to Monitor Effectiveness of Different Types of Customized Orthoses during CrossFit® Training

BACKGROUND

Dynamic balance plays a key role in high-impact sports, such as CrossFit, where athletes are required to maintain balance in various weightlifting exercises. The loss of balance in these sport-specific movements may not only affect athlete performance, but also increase the risk of injuries.

OBJECTIVES

The aim of the study is to achieve greater insight into the balance and athlete position during the CrossFit training by means of inertial sensors, with a particular focus on the role of different custom foot orthoses (CFOs) in order to detect correlations with the role of the cavus foot.

METHODS

A total of 42 CrossFit^® athletes, aged 25 to 42 years, were enrolled in this study. One-way ANOVA tests with post-hoc analysis of variance were used to compare foot posture groups and effects of different types of customized foot orthoses.

RESULTS

When comparing the effects of CFOs with the respective balance basal level during the pistol squat exercise, we observed a significant (p = 0.0001) decrease in the sway area, antero-posterior displacement (APD) and medio-lateral displacement (MLD) compared to the basal using both types of CFOs.

CONCLUSION

No significant positive effects of CFOs were observed in some static tests. On the contrary, positive effects of CFOs and, in particular, postural insoles, are relevant to dynamic balance.

Age and Sex Influence the Use of Modular Femoral Components in Total Hip Arthroplasty Performed for Primary Osteoarthritis

The impact of age and sex on femoral component choices in modular total hip arthroplasty (THA) is still unknown. A regional arthroplasty registry was interrogated about a modular stem in THA performed for primary osteoarthritis, with the aims to assess the influence of age and sex on stems sizes and neck choices. A total of 6830 THAs were included: all THAs had a modular stem (with 15 necks and 27 combinations per side). Patients were stratified by age in decades and sex. Necks were grouped according to the type of correction. The percentage of larger stem sizes increased in males and in elder patients (p < 0.001). Standard necks were overrepresented in males aged 40-59 and underrepresented in males aged 70 or older (p < 0.001). Half of the necks provided other corrections than standard or offset, especially in males aged 40-49 and females aged 70 or older (p < 0.001). Offset necks were predominant in elder patients (p < 0.001). Version-correcting necks were prevalent in younger males and older females (p < 0.001). Varus necks were implanted in one-third of the cases. The four commonest necks showed age and sex specific patterns. In the registry, age and sex impacted stem size and neck choices in THA performed for primary osteoarthritis.

Insights on mechanisms of excess sludge minimization in an oxic-settling-anaerobic process under different operating conditions and plant configurations

In the present research, insights about the mechanisms of excess sludge minimization occurring in an oxic-settling-anaerobic (OSA) were provided. The investigation involved two systems operating in parallel. In particular, a conventional activated sludge (CAS) system as control and a system implementing the OSA process both having a pre-denitrification scheme were considered. Five periods (P1-P5) were studied, during which several operating conditions and configurations were tested. Specifically, the hydraulic retention time (HRT) in the anaerobic reactor of the OSA system (P1 8 h, P2-P3 12 h, P4 8 h, P5 12 h) and the return sludge from the anaerobic to the anoxic (scheme A) (P1-P2) or aerobic (scheme B) mainstream reactors (P3-P5) were investigated. The results highlighted that the excess sludge production in the OSA was lower in all the configurations (12-41%). In more detail, the observed yield (Y_obs) was reduced from 0.50-0.89 gTSS gCOD^-1 (control) to 0.22 -0.34 gTSS gCOD^-1 in the OSA process. The highest excess sludge reduction (40%) was achieved when the OSA was operated according to scheme B and HRT of 12 h in the anaerobic reactor (P3). Generally, scheme A enabled the establishment of cell lysis and extracellular polymeric substances (EPS) destructuration, leading to a worsening of process performances when high anaerobic HRT (>8 h) was imposed. In contrast, scheme B enabled the establishment of maintenance metabolism in addition to the uncoupling metabolism, while cell lysis and EPS destruction were minimized. This allowed obtaining higher sludge reduction yield without compromising the effluent quality.

Constraint in complex primary total knee arthroplasty: rotating hinge versus condylar constrained implants

INTRODUCTION

Condylar constrained knee arthroplasties (CCKAs) and rotating hinge knee arthroplasties (RHKAs) achieved good outcomes in complex primary total knee arthroplasties (TKAs); however, long-term comparative studies are few. Using an arthroplasty registry, we sought to assess and compare in CCKAs and RHKAs: (1) the intra-operative rates of complications, (2) the survival rates, (3) the reasons for revision, and (4) the adjusted hazard ratios for failure.

MATERIALS AND METHODS

1432 constrained implants in primary TKAs performed for non-oncological indications were included: 703 RHKAs, 729 CCKAs. The two groups were comparable regarding age and gender. Kaplan-Meier curves were used to compare survival rates, multivariate analyses to assess the hazard ratios for failures.

RESULTS

The mean follow-up was 4.1 years (range 0-16.3) for CCKAs and 6.8 years (0-18.1) for RHKAs. The intra/peri-operative complications were similar in both the cohorts, with similar rates of femoral and tibial fractures. 10-year implant survival rates were similar in both the cohorts (91.9%, CI 95% 89.2-93.9% in RHKAs; 93.4%, CI 95% 90.3-95.6% in CCKAs). Periprosthetic infection was the most common reason for revision in the two cohorts, followed by aseptic loosening. Breakage occurred in 3 RHKAs (0.4%). CCKAs and RHKAs had a similar distribution of revision causes. Males aged less than 60 had significantly more failures, regardless the constraint degree. Unstemmed CCKAs significantly failed more than RHKAs and stemmed CCKAs.

CONCLUSIONS

Both modern CCKAs and RHKAs are viable long-term solutions in complex primary TKAs. More failures should be expected in males aged less than 60.

LEVEL OF EVIDENCE

IV, Therapeutic study.

Preoperative and postoperative risk factors for periprosthetic joint infection in primary total hip arthroplasty: A 1-year experience

BACKGROUND

Periprosthetic joint infection (PJI) in primary total hip replacement (THR) is one of the most important threats in orthopedic surgery, so one important surgeon’s target is to avoid or early diagnose a PJI. Although the incidence of PJI is very low (0.69%) in our department, with an average follow-up of 595 d, this infection poses a serious threat due to the difficulties of treatment and the lower functional outcomes after healing.

AIM

To study the incidence of PJI in all operations occurring in the year 2016 in our department to look for predictive signs of potential infection.

METHODS

We counted 583 THR for 578 patients and observed only 4 cases of infection (0.69%) with a mean follow-up of 596 d (min 30, max 1451). We reviewed all medical records to collect the data: duration and time of the surgery, presence, type and duration of the antibiotic therapy, preoperative diagnosis, blood values before and after surgery, transfusions, presence of preoperative drugs (in particularly anticoagulants and antiaggregant, corticosteroids and immunosuppressants), presence of some comorbidities (high body mass index, blood hypertension, chronic obstructive pulmonary disease, cardiac ischemia, diabetes, rheumatological conditions, previous local infections).

RESULTS

No preoperative, intraoperative, or postoperative analysis showed a higher incidence of PJI. We did not find any class with evident major odds of PJI. In our study, we did not find any border value to predict PJI and all patients had similar values in both groups (non-PJI and PJI). Only some categories, such as female patients, showed more frequency of PJI, but this difference related to sex was not statistically significant.

CONCLUSION

We did not find any category with a higher risk of PJI in THR, probably due to the lack of few cases of infection.

Environmental commitment of large US publicly traded companies producing healthcare equipment: a cross-sectional comparative study

The environmental commitment of healthcare stakeholders is poorly described despite the sector pollution and the social needs of more sustainable behaviors. A cross-sectional study comparing the environment commitment of US publicly traded companies producing healthcare equipment (HE), healthcare companies (H), and large capitalization corporates (LC) was designed. Using a financial database, the 20 largest US publicly traded companies by market capitalization were selected for each cohort. The last available sustainability report was investigated, aiming to assess (1) the year and the method of dissemination of the last report; (2) the adhesion to environmental standards; (3) the presence of environmental policies, quantitative targets, and tracking; (4) the third-party evaluations about company environmental sustainability. HE companies published sustainability reports in time (p = 0.048), usually as standalone reports (p < 0.001). Half of HE companies adhered to standards, less than the control groups (p < 0.001). HE companies had an acceptable environmental policy, improving over the time and posing targets, similarly to control groups (p > 0.05). The number of companies reporting quantitative targets/tracking about carbon footprint, water, and renewable energy managements differed among the three cohorts (p = 0.013, p = 0.013, and p < 0.001, respectively), with HE cohort achieving the lowest rates (70%, 70%, and 50%, respectively). Carbon neutrality and all renewable energy statements were rare among HE companies (10% and 5% of companies, p < 0.007). In HE, CDP (The Carbon Disclosure Project) scores were lower than controls (p < 0.001). US publicly traded companies producing healthcare equipment demonstrated to be far less committed to environmental sustainability than healthcare companies and large capitalization corporates. Level of evidence: IV.

Which stem in total hip arthroplasty for developmental hip dysplasia? A comparative study using a 3D CT-based software for pre-operative surgical planning

Background

Stem choice in total hip arthroplasty (THA) for hip dysplasia is still controversial. The aims of the study were to evaluate (1) which stem design provided the highest percentage of adequate reconstructions in THA for dysplasia and (2) any correlation between the reconstructions provided by the stems and the native femoral morphology.

Materials and methods

150 CT scans including 200 adult dysplastic hips were randomly selected. Using the 3D CT-based software Hip-Op for surgical planning, the native hip anatomy was studied. Then, a single wedge tapered stem, an anatomical stem and a conical tapered stem were simulated in every hip. An adequate reconstruction of hip biomechanics was obtained when combined anteversion, offset restoration, coronal and sagittal tilt, canal filling and leg lengthening were inside the normal ranges.

Results

Conical stems achieved the highest percentage of adequate reconstructions (87%, p < 0.0001). The anatomical stem was the worst performer. Single wedge and anatomical stem acceptability was mainly influenced by the combined anteversion. Stem anteversion was correlated with the femoral anteversion (fair correlation), the calcar femorale (fair) and the mediolateral femoral diameter at isthmus (poor). When the femoral anteversion was ≥ 25°, combined anteversion was very acceptable for the conical stem (99.2%), whereas the rate of acceptable combined anteversion for the single wedge tapered stem was 71.4%, and that for the anatomical stem was 51.6% (p < 0.0001).

Conclusions

Stem choice in developmental hip dysplasia is mainly driven by appropriate combined anteversion, which is dependent on the coronal and axial femoral morphologies. As a rule of thumb, tapered stems are adequate when femoral anteversion is < 25°; conical stems should be adopted for higher anteversions.

Level of evidence

IV.

A case-driven hypothesis for multi-stage crack growth mechanism in fourth-generation ceramic head fracture

BACKGROUND

Ceramic bearings are used in total hip arthroplasty due to their excellent wear behaviour and biocompatibility. The major concern related to their use is material brittleness, which significantly impacts on the risk of fracture of ceramic components. Fracture toughness improvement has contributed to the decrease in fracture rate, at least of the prosthetic head. However, the root cause behind these rare events is not fully understood. This study evaluated head fracture occurrence in a sizeable cohort of patients with fourth-generation ceramic-on-ceramic implants and described the circumstances reported by patients in the rare cases of head fracture.

METHODS

The clinical survivorship of 29,495 hip prostheses, with fourth-generation ceramic bearings, was determined using data from a joint replacement registry. The average follow-up period was 5.2 years (range 0.1-15.6). Retrieval analysis was performed in one case for which the ceramic components were available.

RESULTS

Clinical outcomes confirmed the extremely low fracture rate of fourth-generation ceramic heads: only two out of 29,495 heads fractured. The two fractures, both involving 36 mm heads, occurred without a concurrent or previous remarkable trauma. Considering the feature of the fractured head, a multi-stage crack growth mechanism has been hypothesized to occur following damage at the head-neck taper interface.

CONCLUSIONS

Surgeons must continue to pay attention to the assembly of the femoral head: achieving a proper head seating on a clean taper is a prerequisite to decrease the risk of occurrence of any damage process within head-neck junction, which may cause high stress concentration at the contact surface, promoting crack nucleation and propagation even in toughened ceramics.

Isolated arthroscopic treatment of intra-articular pathologies in mild hip dysplasia: a short-term case control study

PURPOSE

The aim is to compare the results of isolated hip arthroscopy in patients with borderline dysplasia with Lateral center edge angle (LCEA) between 18° and 25° with a control group of patients with normal LCEA (> 25°).

METHODS

Fifty hip arthroscopies performed in 45 patients were retrospectively evaluated. Exclusion criteria were: age > 40, hip arthritis > grade 2 according to Tonnis classification, femoral head avascular necrosis, pediatric's orthopaedics conditions and true dysplasia with LCEA < 18°.Two groups were identified: group A with 15 hips with LCEA between 25° and 18° and Group control B made of 35 hips with LCEA > 25°.

RESULTS

The groups were homogeneous for demography and pre-operative WOMAC and HOOS. Osteoplasty for CAM were performed in 100% of patients in both groups, only in 12 hips (34.4%) in group B we had both femoral and acetabular osteoplasty. Labral repair was performed in 86% of patients in group A, in 60% of patients in group B, capsular plication in 93% of group A, in 5% of case of group B. WOMAC and HOOS statically significant improved in both groups at final follow-up (24 months). No cases in both groups required conversion to total hip arthroplasty. Clinical outcomes of study group were comparable to the control group.

CONCLUSION

Even if the present small series is not conclusive, we suggest isolated arthroscopic management of patients with FAI and LCEA between 18° and 25°, but capsular plication and careful labral management are strongly recommended.

LEVEL OF EVIDENCE

Level IV.