There are numerous studies in the current literature that have demonstrated altered levels of various biomarkers in the serum of patients with implant loosening. Despite increasing interest in the biology of implant incorporation there are no studies investigating the changes in biological marker (of either osteoblastic or osteoclastic activity) levels during the integration of the bone-implant interface. Such a study would provide data about the biological profile of normal integration and would be helpful for future monitoring of implant prosthetic performance (either normal or abnormal). We present data from a study performed on 100 osteoarthritic patients, who underwent cementless THA (Synergy, Reflexion Interfit, Smith & Nephew) and 100 non arthritic volunteers. Serial measurements of serum biochemical markers (bone formation and resorption), of cytokines and of other biological mediators and growth factors were evaluated at regular intervals over the course of six years. Curves of per cent changes from baseline and marker variability curves have been created for each marker which are indicative of the incorporation process. Evaluating markers of osteoblastic activity, a first response, with average values below baseline, was observed at the level of the seventh day (perhaps as a response to local trauma). A second osteo-productive response was observed between the third week and 9 months (peak average values at the level of the 6. th. month). At the 1st year time interval, average values reached baseline and remained at this level up to the 6th postoperative year. Evaluating markers of osteoclastic activity, a first response, with average values above baseline, was observed at the level of the seventh day (perhaps as a response to local trauma). A second osteoclastic response was observed between the third week and 3 months (perhaps a coupling response to enhanced osteoblastic activity). At 6 months, average values reached baseline and remained at this level up to the 6th postoperative year. It seems that bone implant interface in cementless total hip arthroplasty remains active up to the 9. th. postoperative month. Possible future deviation from such ‘individual normal’ curves will be indicative of the initiation of the osteolysis process and loss of fixation

Recent studies about hip stability after total hip arthroplasties (THA) concerned differences regarding bearings: ceramic on ceramic (CoC) presenting less dislocations on the long term compared to metal or ceramic on polyethylene. The hypothesis is a difference in the healing process of periarticular tissues, with a stronger fibrous tissue for the first one, and more foreign body reaction, joint effusion with the others.

NMR Imaging of the pelvis showing both hips using novel MR MAVRIC program for metal artefacts suppression, were performed in 10 patients, 15 THA and 2 non-pathological contralateral hips. Eight hips had CoC bearings, 3 of which were impacted cementless bulky ceramic implant, and 5 had a metal back. 7 hips had CoP bearings, 4 of which were cemented.

Native capsules showed a mean thickness of 6.6mm. For CoC bearings, capsule thickness ranged from 7mm to 9.6 mm with a mean thickness of 8mm. For CoP bearings, capsule thickness ranged from 3mm to 8.4mm, with a mean thickness of 6.1mm. Neocapsule appeared clearly in all COC bearings observed, while for CoP, sometimes it was less dense with fatty aspect, 3 hips out of 7 having a very thin capsule under 4mm.

It is possible to observe and quantify new capsule after THR and measure differences although not significant regarding bearings on limited number of samples. More patients might be included, but the tendencies observed here might explain better long term stability in vivo observed with Coc.

The management of severe acetabular bone defects poses a complex challenge in revision hip arthroplasty. Although biological fixation materials are currently dominant, cage has played an important role in complex acetabular revision in the past decades, especially when a biological prosthesis is not available. The purpose of this study is to report the long-term clinical and radiographic results of Paprosky type Ⅲ acetabular bone defects revised with cage and morselized allografts. We retrospectively analyzed 45 patients who underwent revision hip arthroplasty with cage and morselized allografts between January 2007 and January 2019. Forty-three patients were followed up. There were 19 Paprosky type IIIA bone defect patients and 24 Paprosky type IIIB bone defect patients and 7 patients of the 24 were also with pelvic discontinuity. Clinical assessment included Harris Hip Score (HHS) and Short Form-12 (SF-12). Radiographic assessment included cage stability, allografts incorporation, and center of rotation. All patients were followed up with a mean follow-up of 10.6 years, HHS and SF-12 improved significantly at last follow-up in comparison to the preoperative. There were 2 re-revisions, one at 5 years after surgery, another at 13.6 years after surgery. Two patients had nonprogressive radiolucency in zone III and the junction of zone II and zone III at the bone implant interface. Allografts of 40 (93%) cases incorporated fully. The combination of cage and morselized allograft is an alternative option for acetabular revision with Paprosky type III bone defects with satisfactory long-term follow-up results

In primary total hip arthroplasty (THA) for patients with Crowe II or higher classes developmental dysplasia of the hip (DDH) or rapidly destructive coxopathy (RDC), the placement of the cup can be challenging due to superior and lateral acetabular bone defects. Traditionally, bone grafts from resected femoral heads were used to fill these defects, but bulk graft poses a risk of collapse, especially in DDH with hypoplastic femoral heads or in RDC where good quality bone is scarce. Recently, porous metal augments have shown promising outcomes in revision surgeries, yet reports on their efficacy in primary THA are limited. This study retrospectively evaluated 27 patients (30 hips) who underwent primary THA using cementless cups and porous titanium acetabular augments for DDH or RDC, with follow-up periods ranging from 2 to 10 years (average 4.1 years). The cohort included 22 females (24 hips) and 5 males (6 hips), with an average age of 67 years at the time of surgery. The findings at the final follow-up showed no radiographic evidence of loosening or radiolucency around the cups and augments, indicating successful biological fixation in all cases. Clinically, there was a significant improvement in the WOMAC score from an average of 39.1±14.7 preoperatively to 5.1±6.4 postoperatively. These results suggest that the use of cementless cups and porous titanium acetabular augments in primary THA for DDH and RDC can lead to high levels of clinical improvement and reliable biological fixation, indicating their potential as a viable solution for managing challenging acetabular defects in these conditions

Aims. Aseptic loosening is a leading cause of uncemented arthroplasty failure, often accompanied by fibrotic tissue at the bone-implant interface. A biological target, neutrophil extracellular traps (NETs), was investigated as a crucial connection between the innate immune system’s response to injury, fibrotic tissue development, and proper bone healing. Prevalence of NETs in peri-implant fibrotic tissue from aseptic loosening patients was assessed. A murine model of osseointegration failure was used to test the hypothesis that inhibition (through Pad4-/- mice that display defects in peptidyl arginine deiminase 4 (PAD4), an essential protein required for NETs) or resolution (via DNase 1 treatment, an enzyme that degrades the cytotoxic DNA matrix) of NETs can prevent osseointegration failure and formation of peri-implant fibrotic tissue. Methods. Patient peri-implant fibrotic tissue was analyzed for NETs biomarkers. To enhance osseointegration in loose implant conditions, an innate immune system pathway (NETs) was either inhibited (Pad4-/- mice) or resolved with a pharmacological agent (DNase 1) in a murine model of osseointegration failure. Results. NETs biomarkers were identified in peri-implant fibrotic tissue collected from aseptic loosening patients and at the bone-implant interface in a murine model of osseointegration failure. Inhibition (Pad4-/-) or resolution (DNase 1) of NETs improved osseointegration and reduced fibrotic tissue despite loose implant conditions in mice. Conclusion. This study identifies a biological target (NETs) for potential noninvasive treatments of aseptic loosening by discovering a novel connection between the innate immune system and post-injury bone remodelling caused by implant loosening. By inhibiting or resolving NETs in an osseointegration failure murine model, fibrotic tissue encapsulation around an implant is reduced and osseointegration is enhanced, despite loose implant conditions. Cite this article: Bone Joint J 2021;103-B(7 Supple B):135–144

Pelvic discontinuity is a separation through the acetabulum with the ilium displacing superiorly and the ischium/pubis displacing inferiorly. This is a biomechanically challenging environment with a high rate of failure for standard acetabular components. The cup-cage reconstruction involves the use of a highly porous metal cup to achieve biological bone ingrowth on both sides of the pelvic discontinuity and an ilioischial cage to provide secure fixation across the discontinuity and bring the articulating hip center to the correct level. The purpose of this study was to report long term follow up of the use of the cup-cage to treat pelvic discontinuity. All hip revision procedures between January 2003 and January 2022 where a cup-cage was used for a hip with a pelvic discontinuity were included in this retrospective review. All patients received a Trabecular Metal Revision Shell with either a ZCA cage or TMARS cage (Zimmer-Biomet Inc.). Pelvic discontinuity was diagnosed on pre-operative radiographs and/or intraoperatively. Kaplan-Meier survival analysis was performed with failure defined as revision of the cup-cage reconstruction. Fifty-seven cup-cages in 56 patients were included with an average follow-up of 6.25 years (0.10 to 19.98 years). The average age of patients was 72.09 years (43 to 92 years) and 70.2% of patients were female. The five year Kaplan-Meier survival was 92.0% (95% CI 84.55 to 99.45) and the ten year survival was 80.5% (95% CI 58.35 to 102.65). There were 5 major complications that required revision of the cup-cage reconstruction (3 infections and 2 mechanical failures). There were 9 complications that required re-operation without revision of the cup-cage reconstruction (5 dislocations, 3 washouts for infection and one femoral revision for aseptic loosening). In our hands the cup-cage reconstruction has provided a reliable tool to address pelvic discontinuity with an acceptable complication rate

Aims. Developmental dysplasia of the hip (DDH) is a complex musculoskeletal disease that occurs mostly in children. This study aimed to investigate the molecular changes in the hip joint capsule of patients with DDH. Methods. High-throughput sequencing was used to identify genes that were differentially expressed in hip joint capsules between healthy controls and DDH patients. Biological assays including cell cycle, viability, apoptosis, immunofluorescence, reverse transcription polymerase chain reaction (RT-PCR), and western blotting were performed to determine the roles of the differentially expressed genes in DDH pathology. Results. More than 1,000 genes were differentially expressed in hip joint capsules between healthy controls and DDH. Both gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that extracellular matrix (ECM) modifications, muscle system processes, and cell proliferation were markedly influenced by the differentially expressed genes. Expression of Collagen Type I Alpha 1 Chain (COL1A1), COL3A1, matrix metalloproteinase-1 (MMP1), MMP3, MMP9, and MMP13 was downregulated in DDH, with the loss of collagen fibres in the joint capsule. Expression of transforming growth factor beta 1 (TGF-β1) was downregulated, while that of TGF-β2, Mothers against decapentaplegic homolog 3 (SMAD3), and WNT11 were upregulated in DDH, and alpha smooth muscle actin (αSMA), a key myofibroblast marker, showed marginal increase. In vitro studies showed that fibroblast proliferation was suppressed in DDH, which was associated with cell cycle arrest in G0/G1 and G2/M phases. Cell cycle regulators including Cyclin B1 (CCNB1), Cyclin E2 (CCNE2), Cyclin A2 (CCNA2), Cyclin-dependent kinase 1 (CDK1), E2F1, cell division cycle 6 (CDC6), and CDC7 were downregulated in DDH. Conclusion. DDH is associated with the loss of collagen fibres and fibroblasts, which may cause loose joint capsule formation. However, the degree of differentiation of fibroblasts to myofibroblasts needs further study. Cite this article: Bone Joint Res 2021;10(9):558–570

Aims. The purpose of this study was to evaluate the biological fixation of a 3D printed porous implant, with and without different hydroxyapatite (HA) coatings, in a canine model. Materials and Methods. A canine transcortical model was used to evaluate the characteristics of bone ingrowth of Ti6Al4V cylindrical implants fabricated using laser rapid manufacturing (LRM). At four and 12 weeks post-implantation, we performed histological analysis and mechanical push-out testing on three groups of implants: a HA-free control (LRM), LRM with precipitated HA (LRM-PA), and LRM with plasma-sprayed HA (LRM-PSHA). Results. Substantial bone ingrowth was observed in all LRM implants, with and without HA, at both time periods. Bone ingrowth increased from 42% to 52% at four weeks, to 60% to 65% at 12 weeks. Mechanical tests indicated a minimum shear fixation strength of 20 MPa to 24 MPa at four weeks, and 34 MPa to 40 MPa at 12 weeks. There was no significant difference in the amount of bone ingrowth or in the shear strength between the three implant types at either time period. Conclusion. At four and 12 weeks, the 3D printed porous implants exhibited consistent bone ingrowth and high mechanical shear strength. Based on the results of this study, we confirmed the suitability of this novel new additive manufacturing porous material for biological fixation by bone ingrowth. Cite this article: Bone Joint J 2019;101-B(6 Supple B):62–67

In a recent phase 2 superiority clinical trial we demonstrated that a single dose of 60mg of the human monoclonal antibody denosumab inhibits osteolytic lesion activity in patients undergoing revision total hip arthroplasty (THA), demonstrating proof of biological efficacy for this clinical application. Here, we examined the effect that denosumab has on disease biology at the osteolysis tissue level. Osteolytic tissue taken from the prosthesis-bone lesion interface at revision surgery in patients with osteolysis (n=10 participants that had received a single 60 mg dose of denosumab 8 weeks prior to revision surgery and n=10 that had received placebo) was examined for total genetic message activity and protein levels using whole genome sequencing and mass spectrometry, respectively. The top five upregulated enriched pathways with denosumab treatment included inflammatory response, myeloid cell activation, myeloid leukocyte migration, neutrophil and granulocyte activation (p<6.26 × 10. −28. ). Cell morphogenesis was amongst the most downregulated pathways (p<3.42 ×10. −23. ). Finally, comparison of the trial mRNA and protein data versus mouse single cell RNA sequencing data of the same pathway blockade in mouse tibia showed the same direction of effect, suggesting that giving the drug causes then cells responsible for osteolysis to disperse into a more immature form (128 of 189 genes (z=4.87, P<0.0001) disease and functional pathways at the mRNA level and 10 of 11 (z=2.72, P=0.0065) at the protein level). In this first-in-man study we identify multiple genes and pathways within periprosthetic osteolysis tissue that are affected by denosumab treatment. The dominant pathways involved upregulation of innate inflammatory signaling and downregulation of cell morphogenesis. We also found enrichment of similar disease and functional pathways at both the mRNA and protein levels versus mRNA pathway enrichment found in mouse osteomorphs. These data provide the first human data of the mechanistic effect of denosumab treatment on inflammatory osteolytic lesion activity after joint replacement that is necessary to support its clinical application. ∗Winner of The Bone & Joint Journal prize∗

To date there is no medical treatment alternative to surgery for osteolysis after THA. In this proof-of-concept clinical trial we examined the effect of a human monoclonal antibody against osteoclasts versus placebo on osteolytic lesion activity in patients undergoing revision surgery. Patients scheduled for revision for symptomatic osteolysis were randomised (1:1) to receive either denosumab 60mg or placebo subcutaneously eight weeks prior to operation. At surgery, biopsies from the osteolytic membrane-bone interface were taken for histomorphometric analysis of osteoclast number. Secondary outcome measures included systemic bone turnover markers. 22 subjects completed the study (10 denosumab). The denosumab group had 83% (−63 to −97), P=0.011 fewer osteoclasts at osteolytic lesion sites, 87% lower osteoclast surface (−65 to −95, P=0.009), and 72% lower eroded surface (−35 to −93, P=0.020) versus the placebo group. At surgery, serum CTX-I, TRAP5b and PINP were 80% (−65 to −95, p<0.001), 57% (−40 to −90, p<0.001), and 44% (−41 to −65, p<0.001) lower in the denosumab versus placebo groups, respectively. The rate of adverse events (denosumab 6, placebo 7) were similar between groups (P>0.05). These data provide a biological basis for a definitive clinical trial using pain, function and prosthesis survival as the study endpoints. As osteolysis/ aseptic loosening is the leading cause of prosthesis failure world-wide, the establishment of a non-surgical solution would reduce patient suffering and dramatically reducing the cost to healthcare economies

The goal of the study was to describe the features of the aseptic loosening of the cup in CoC THR and to determine factors that affect the time to revision. It is a retrospective study including all patients who had a revision of CoC THR for aseptic failure fixation of the cup, between 2007 and 2017. 55 patients (27 women, 28 men) (56 hips) were included in the study. Eight hips (13 %) had also a stem exchange. At the primary T HR, the mean age of the patients was 47.9 years (17–72), 28 press fit cups had screws, the mean diameter of the cup was 51.2 mm (46–62) and the mean inclination was 52° (37–67). Clinical and radiological data were retrospectively recorded by an observer different to the initial operators. The mean age of the patients at the revision was 55.4 years (26–84). The mean time to revision was 90.1 months (14–240), and was significantly greater in patients aged less than 52 years, in cups without screws and with a 28mm head. The trend curve of the time to cup revision showed a bimodal distribution at three and ten years. 20 cups had migrated (33%). Bone loss was rated type 1 in 41 hips (73.0%), type 2 in 12 hips and type 3 in three hips). The mean diameter of the new cup was 52.3 mm (46–64). It was inferior to that of the initial cup in 26 hips (46.4%). 31 cups were impacted (55.5%) and 25 needed to be cemented (45.5%). No macroscopic wear was detected on the ceramic implant. Aseptic loosening of the cup in CoC THA does not appear to increase over time, supporting the fact that the failure is unrelated to wear and is not due to a biological mechanism. The occurrence of two peaks of frequency over time may suggest that different mechanisms occur

Hemiarthroplasty (HA) and total hip arthroplasty (THA) have both been well described as effective methods of management for displaced femoral neck fractures in the elderly. THA has superior functional outcomes and lower long-term revision rates, while HA is associated with lower dislocation rates and faster operative times. While HA remains an appropriate management option in low-demand patients, it is commonly complicated by acetabular erosion. However, there is no consensus about the preferred method of treatment in self-sufficient, physically active patients with normal cognition. The aim of this study was to evaluate the impact of age in geriatric patients with acetabular wear after bipolar HA. We retrospectively reviewed the records of all cases of femoral neck fractures treated with bipolar HA in our institution, during the period 2013 – 2020. According to the age at the time of fracture, patients were separated in 3 groups: Group A (age 70 – 75), group B (age 75 – 80) and group C (age > 80). Acetabular wear was defined as failure of the acetabulum, which needed revision to THA. A total of 1410 patients (861 females and 549 males, mean age 77,2 years) were included in the study. 359 patients were included in Group A, 592 in Group B and 459 in Group C. Mean follow-up was 3.2 years. There were no significant differences in sex distribution, injury side, fracture pattern, BMI, ASA score, bipolar head diameter and leg length discrepancy among the 3 groups. The incidence of acetabular wear and need for revision to THA was 6.13%, 4.22% and 1.96% respectively (p = 0.009). The higher rate of acetabular wear in patients less than 75 years suggests that THA is a more viable option for these patients. In group 75–80 years old decision for HA or THA should be made upon patient's activity status and biological age while above the age of 80 years old, Hemi seems to be the preferred solution

The management of prosthetic joint infection (PJI) has been widely performed for total hip arthroplasties (THA), but none has compared it with hip resurfacing arthroplasty (RSA). We also carried out a retrospective case-control study comparing the surgical treatment of PJI by surgical debridement and implant retention between RSA and THA in order to clarify whether there was a difference in terms of (1) successful healing of PJI (2) functional scores after recovery (3) risk factors for recurrence of PJI. Our hypothesis was that simple debridement with prosthesis retention regardless of the timeframe allowed to obtain a higher success rate for RSA compared to THA. From 2010 to 2018, a single-center case-control study based on 3056 RSA found 13 PJI were age-matched (based on the 139 THA PJI treated) with 15 THA PJI (mean age of 53 years old (47–58) for THA and 59 (45–66) for RSA (p=0.34)). We compared their survival (absence of infectious recurrence) and the means differences between the 2 groups (demographical, clinical and biological data). There was no difference between the 2 groups concerning: age (p=0.3), BMI (p=0.4), initial diagnosis (p=0.4), operating time for primary surgery (p=0.3), the presence of a postoperative hematoma (p=0.4), the type of bacteria (p=0.5), the total duration of antibiotic therapy (p=0.9) and the type of antibiotic therapy (p=0.6). Early postoperative infections (less than 6 weeks) occurred in 7/13 RSA cases (54%) compared to 11/15 THA cases (73%). At the mean follow-up of 5 years (2–7), the success rate without recurrence was significantly higher in the RSA group 100% versus 66.7% (10/15) for the THA group (p=0.044). At the last follow-up, the Oxford Hip Score was higher in the RSA versus THA group's (14 versus 22 p=0.004). Simple surgical debridement an RSA without changing implants after PJI can be done regardless of the time to onset of infection. This is secondary to the absence of metaphyseal bone invasion and the low content of joint fluid

Introduction. Patients with rheumatoid arthritis (RA) have a higher risk of surgical site infection (PJI) than patients with osteoarthritis (OA). Disease modifying therapy is in widespread use in RA patients, and biologic medications may increase Staphylococcus aureus colonization rates. Because S. aureus colonization likely increases risk of surgical infection, perioperative assessments and therapies to decrease the risk of invasive S.aureus infections may be warranted. The objective of this study was to determine if there was a difference in S. aureus carriage among patients with RA, OA, and RA on biologics (RA+B). Methods. An a priori power analysis determined 123 participants per group were needed to detect a relative difference of 20% among groups with 80% power. After IRB approval, patients were screened; included patients met American College of Rheumatology classification criteria. Patients were approached between April 2017 and May 2018 and asked to perform a nasal swab while on site using the Center for Disease Control's swabbing protocol; questionnaires pertaining to their current health status were collected. Swabs were inoculated onto ChromAgar/ChromID MRSA plates for detection of S. aureus. Mann-Whitney U and Chi-square tests were used to evaluate baseline differences between groups. Logistic regression evaluated the associations between groups and S. aureus carriage. All statistical analyses were performed using SAS Software version 9.3 (SAS Institute, Cary, NC); statistical significance was defined as p<0.05. Results. Overall the patient cohort evaluated had a mean age of 66 (+/-13.7), BMI of 29 (+/-28.2), and were predominantly female (78%) .28% of the cohort was on antibiotics within three months prior to the nasal swab, 18% were currently on steroids, and 24% had been hospitalized within the last year. We found differences in age (p<0.001), BMI (p<0.001), sex (p<0.001), diabetes (p=0.04), steroid use (p=0.02), antibiotic use (p<0.001), and hospitalizations within the last year (p<0.001). S. aureus carriage was most prevalent in RA+B37%, followed by RA (24%), and OA (20%). After multivariate adjustment, RA+B was found to have increased odds of S. aureus (OR=1.80, 95% CI 1.00–3.22); p=0.047) compared to RA group. Use of glucocorticoids, hospitalization, or diabetes did not increase the odds of S. aureus carriage. The OA group had decreased odds of S. aureus growth when compared to the RA group; however, this was not found to be statistically significant (p=0.987). Conclusion. RA patients treated with biologics have an increased prevalence of S. aureus colonization. Since nasal S. aureus carriage may play a role in the pathogenesis of surgical infections, S. aureus decolonization should be considered in RA patients on biologics prior to elective surgery

Aims. The prevalence of ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is rising in concert with life expectancy, putting more patients at risk for interprosthetic femur fractures (IPFFs). Our study aimed to assess treatment methodologies, implant survivorship, and IPFF clinical outcomes. Methods. A total of 76 patients treated for an IPFF from February 1985 to April 2018 were reviewed. Prior to fracture, at the hip/knee sites respectively, 46 femora had primary/primary, 21 had revision/primary, three had primary/revision, and six had revision/revision components. Mean age and BMI were 74 years (33 to 99) and 30 kg/m. 2. (21 to 46), respectively. Mean follow-up after fracture treatment was seven years (2 to 24). Results. Overall, 59 fractures were classified as Vancouver C (Unified Classification System (UCS) D), 17 were Vancouver B (UCS B). In total, 57 patients (75%) were treated with open reduction and internal fixation (ORIF); three developed nonunion, three developed periprosthetic joint infection, and two developed aseptic loosening. In all, 18 patients (24%) underwent revision arthroplasty including 13 revision THAs, four distal femoral arthroplasties (DFAs), and one revision TKA: of these, one patient developed aseptic loosening and two developed nonunion. Survivorship free from any reoperation was 82% (95% confidence interval (CI) 66.9% to 90.6%) and 77% (95% CI 49.4% to 90.7%) in the ORIF and revision groups at two years, respectively. ORIF patients who went on to union tended to have stemmed knee components and greater mean interprosthetic distance (IPD = 189 mm (SD 73.6) vs 163 mm (SD 36.7); p = 0.546) than nonunited fractures. Patients who went on to nonunion in the revision arthroplasty group had higher medullary diameter: cortical width ratio (2.5 (SD 1.7) vs 1.3 (SD 0.3); p = 0.008) and lower IPD (36 mm (SD 30.6) vs 214 mm (SD 32.1); p < 0.001). At latest follow-up, 95% of patients (n = 72) were ambulatory. Conclusion. Interprosthetic femur fractures are technically and biologically challenging cases. Individualized approaches to internal fixation versus revision arthroplasty led to an 81% (95% CI 68.3% to 88.6%) survivorship free from reoperation at two years with 95% of patients ambulatory. Continued improvements in management are warranted. Cite this article: Bone Joint J 2021;103-B(7 Supple B):122–128

Aims. Posterior tilt of the pelvis with sitting provides biological acetabular opening. Our goal was to study the post-operative interaction of skeletal mobility and sagittal acetabular component position. Materials and Methods. This was a radiographic study of 160 hips (151 patients) who prospectively had lateral spinopelvic hip radiographs for skeletal and implant measurements. Intra-operative acetabular component position was determined according to the pre-operative spinal mobility. Sagittal implant measurements of ante-inclination and sacral acetabular angle were used as surrogate measurements for the risk of impingement, and intra-operative acetabular component angles were compared with these. Results. Post-operatively, ante-inclination and sacral acetabular angles were within normal range in 133 hips (83.1%). A total of seven hips (4.4%) had pathological imbalance and were biologically or surgically fused hips. In all, 23 of 24 hips had pre-operative dangerous spinal imbalance corrected. Conclusions. In all, 145 of 160 hips (90%) were considered safe from impingement. Patients with highest risk are those with biological or surgical spinal fusion; patients with dangerous spinal imbalance can be safe with correct acetabular component position. The clinical relevance of the study is that it correlates acetabular component position to spinal pelvic mobility which provides guidelines for total hip arthroplasty. Cite this article: Bone Joint J 2017;99-B(1 Supple A):37–45

Aims

Current diagnostic tools are not always able to effectively identify periprosthetic joint infections (PJIs). Recent studies suggest that circulating microRNAs (miRNAs) undergo changes under pathological conditions such as infection. The aim of this study was to analyze miRNA expression in hip arthroplasty PJI patients.

Introduction. The prevalence of ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is rising in concert with life expectancy, putting more patients at risk for interprosthetic femur fractures (IPFF). Our study aimed to assess treatment methodologies, implant survivorship, and clinical outcomes of patients with IPFF. Methods. 77 patients treated for an IPFF from 1985–2017 at a single large referral center were reviewed. Prior to the fracture, at the hip/knee sites respectively 46 femurs had primary/primary, 21 had revision/primary, 3 had primary/revision and 7 had revision/revision components. Mean age and BMI were 74 years and 30 kg/m. 2. , respectively. Mean follow-up after fracture treatment was 7 years. Results. Sixty fractures were classified as Vancouver C (UCS D) while 17 were Vancouver B (UCS B). Fifty-seven patients (74%) were treated with ORIF; 3 developed a non-union, 3 developed a PJI, and 2 developed aseptic loosening. Nineteen patients (25%) were treated with revision arthroplasty including: 13 revision THAs, 4 distal femoral replacements, 1 revision TKA, and 1 total femoral replacement of which 2 developed aseptic loosening and 2 developed a non-union. Survivorship free from any reoperation for the entire cohort was 79% at 2 years. Patients in the ORIF group who went on to union tended to have stemmed components and greater interprosthetic distance (IPD=189mm vs. 163mm, p=0.55) than non-united fractures. Patients who went on to nonunion in the revision arthroplasty group had higher medullary diameter: cortical width ratio (2.5 vs. 1.3, p=0.01) and lower IPD (36mm vs. 202mm, p=0.002). 95% of patients were ambulatory at latest follow-up. Conclusion. Interprosthetic femur fractures are technically and biologically challenging cases. An individualized approach of internal fixation versus revision arthroplasty led to a 79% success rate free of reoperation at 2 years with 95% of patients ambulatory. Continued improvements in management are warranted

Objectives. We investigated the reliability of the cobalt-chromium (CoCr) synovial joint fluid ratio (JFR) in identifying the presence of a severe aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) response and/or suboptimal taper performance (SOTP) following metal-on-metal (MoM) hip arthroplasty. We then examined the possibility that the CoCr JFR may influence the serum partitioning of Co and Cr. Methods. For part A, we included all revision surgeries carried out at our unit with the relevant data, including volumetric wear analysis, joint fluid (JF) Co and Cr concentrations, and ALVAL grade (n = 315). Receiver operating characteristic curves were constructed to assess the reliability of the CoCr JFR in identifying severe ALVAL and/or SOTP. For part B, we included only patients with unilateral prostheses who had given matched serum and whole blood samples for Co and Cr analysis (n = 155). Multiple regression was used to examine the influence of JF concentrations on the serum partitioning of Co and Cr in the blood. Results. A CoCr JFR > 1 showed a specificity of 83% (77% to 88%) and sensitivity of 63% (55% to 70%) for the detection of severe ALVAL and/or SOTP. In patients with CoCr JFRs > 1, the median blood Cr to serum Cr ratio was 0.99, compared with 0.71 in patients with CoCr JFRs < 1 (p < 0.001). Regression analysis demonstrated that the blood Cr to serum Cr value was positively associated with the JF Co concentration (p = 0.011) and inversely related to the JF Cr concentration (p < 0.001). Conclusion. Elevations in CoCr JFRs are associated with adverse biological (severe ALVAL) or tribocorrosive processes (SOTP). Comparison of serum Cr with blood Cr concentrations may be a useful additional clinical tool to help to identify these conditions. Cite this article: D. J. Langton, S. Natu, C. F. Harrington, J. G. Bowsher, A. V. F. Nargol. Is the synovial fluid cobalt-to-chromium ratio related to the serum partitioning of metal debris following metal-on-metal hip arthroplasty? Bone Joint Res 2019;8:146–155. DOI: 10.1302/2046-3758.83.BJR-2018-0049.R1

Aims

This study aimed to assess the carbon footprint associated with total hip arthroplasty (THA) in a UK hospital setting, considering various components within the operating theatre. The primary objective was to identify actionable areas for reducing carbon emissions and promoting sustainable orthopaedic practices.