Impact of fixation method on femoral bone loss: a retrospective evaluation of stem loosening in first-time revision total hip arthroplasty among two hundred and fifty five patients.

PURPOSE: Implant loosening represent the most common indication for stem revision in hip revision arthroplasty. This study compares femoral bone loss and the risk of initial revisions between cemented and uncemented loosened primary stems, investigating the impact of fixation method at primary implantation on femoral bone defects. METHODS: This retrospective study reviewed 255 patients who underwent their first revision for stem loosening from 2010 to 2022, receiving either cemented or uncemented stem implants. Femoral bone loss was preoperatively measured using the Paprosky classification through radiographic evaluations. Kaplan-Meier analysis estimated the survival probability of the original stem, and the hazard ratio assessed the relative risk of revision for uncemented versus cemented stems in the first postoperative year and the following two to ten years. RESULTS: Cemented stems showed a higher prevalence of significant bone loss (type 3b and 4 defects: 32.39% vs. 2.72%, p < .001) compared to uncemented stems, which more commonly had type 1 and 2 defects (82.07% vs. 47.89%, p < .001). In our analysis of revision cases, primary uncemented stems demonstrated a 20% lower incidence of stem loosening in the first year post-implantation compared to cemented stems (HR 0.8; 95%-CI 0.3-2.0). However, the incidence in uncemented stems increased by 20% during the subsequent years two to ten (HR 1.2; 95%-CI 0.7-1.8). Septic loosening was more common in cemented stems (28.17% vs. 10.87% in uncemented stems, p = .001). Kaplan-Meier analysis indicated a modestly longer revision-free period for cemented stems within the first ten years post-implantation (p < .022). CONCLUSION: During first-time revision, cemented stems show significantly larger femoral bone defects than uncemented stems. Septic stem loosening occurred 17.30% more in cemented stems.

Success Rate After 2-Stage Spacer-Free Total Hip Arthroplasty Exchange and Risk Factors for Reinfection: A Prospective Cohort Study of 187 Patients.

BACKGROUND: Two-stage prosthesis exchange is the treatment of choice for chronic periprosthetic joint infection (PJI) of a total hip arthroplasty (THA), especially when the bone and surrounding soft tissues are compromised or difficult-to-treat pathogens are implicated. The aims of our study were as follows: (1) to determine the outcome of 2-stage prosthesis exchange for the treatment of PJI after THA and (2) to determine the risk factors for reinfection leading to subsequent revision surgeries after reimplantation. METHODS: We prospectively enrolled 187 consecutive patients who underwent a 2-stage THA exchange with resection arthroplasty for PJI from 2013 to 2019. The mean (± SD) duration of follow-up was 54.2 ± 24.9 months (range, 36 to 96), and the mean interval until reimplantation was 9.8 ± 8.9 weeks (range, 2 to 38). All patients remained in a spacer-free girdlestone situation between the 2 stages of treatment. Patients who remained infection-free after their 2-stage treatment were considered to have achieved treatment success. RESULTS: The overall success rate was 85.6%. The cumulative probability of reinfection was 11.5% after one year and 14% after 2 years after reimplantation. High virulence or difficult-to-treat pathogens were significant and independent risk factors for reinfection (HR [hazard ratio] = 3.71, 95% CI [confidence interval]: 1.47 to 9.36, P = .006 and HR = 3.85, 95% CI: 1.73 to 8.57, respectively, P = .001), as was previous 2-stage hip prosthesis exchange (HR = 3.58, 95% CI: 1.33 to 9.62, P = .01). Overall reoperation and revision rates were 26.2 and 16.6%, respectively. Re-infected patients had an 80% higher probability of reoperation than noninfected ones (P < .001, log-rank = 102.6), and they were 55% more likely to undergo revision surgery during their follow-up (P < .001, log-rank = 55.4). CONCLUSIONS: Reinfection rates after 2-stage spacer-free THA revision for PJI still remain high but are comparable to those including cement spacers. Patients who have had prior failed 2-stage implant exchanges or are infected by high-grade or difficult-to-treat pathogens are at high risk for treatment failure.

Recruitment of plasma cells from IL-21-dependent and IL-21-independent immune reactions to the bone marrow.

Bone marrow plasma cells (BMPC) are the correlate of humoral immunity, consistently releasing antibodies into the bloodstream. It remains unclear if BMPC reflect different activation environments or maturation of their precursors. Here we define human BMPC heterogeneity and track the recruitment of antibody-secreting cells (ASC) from SARS-CoV-2 vaccine immune reactions to the bone marrow (BM). Trajectories based on single-cell transcriptomes and repertoires of peripheral and BM ASC reveal sequential colonisation of BMPC compartments. In activated B cells, IL-21 suppresses CD19 expression, indicating that CD19low-BMPC are derived from follicular, while CD19high-BMPC originate from extrafollicular immune reactions. In primary immune reactions, both CD19low- and CD19high-BMPC compartments are populated. In secondary immune reactions, most BMPC are recruited to CD19high-BMPC compartments, reflecting their origin from extrafollicular reactivations of memory B cells. A pattern also observable in vaccinated-convalescent individuals and upon diphtheria/tetanus/pertussis recall-vaccination. Thus, BMPC diversity reflects the evolution of a given humoral immune response.

The Subjective Hip Value is a Valid, Reliable, and Responsive Instrument for Assessing Hip Function in Primary Total Hip Arthroplasty.

BACKGROUND: Patient-reported outcome measures are essential tools in clinical decision-making and research. Multi-item scores like the modified Harris Hip Score (mHHS) are time-consuming to collect and evaluate. The subjective hip value (SHV), as a single-item value, assesses hip function with one question: "What is the overall percent value of your hip if a completely normal hip represents 100%?". The aims of our study were to assess the psychometric properties, and thus validity, reliability, and responsiveness; and to define the minimal clinically important difference (MCID) of the SHV in patients undergoing total hip arthroplasty. METHODS: A total of 137 consecutive patients who underwent primary total hip arthroplasty between June 2020 and August 2021 were prospectively enrolled. A SHV and mHHS were collected preoperatively and at follow-ups (6 weeks, 3 months, 6 months, and 1 year). Validity, reliability, responsiveness, MCID, and floor/ceiling effects were evaluated. RESULTS: There was a significant correlation between SHV and mHHS (P = .001) preoperatively (rs = 0.532), 6 weeks (rs = 0.649), 3 months (rs = 0.765), 6 months (rs = 0.854), and after 1 year (rs = 0.879). Test-retest reliability (rs = 0.74; P = .001) and responsiveness (rs = 0.24; P = .007) showed significant correlations. The MCID for SHV was 10.06%. Floor- and ceiling-effects were comparable to the mHHS. CONCLUSIONS: The SHV is a valid, reliable, and responsive single-item score for the assessment of hip joint function in arthroplasty patients. It can detect clinically relevant changes in joint function and is easy to collect and interpret, which justifies its implementation in clinical practice.

Allogeneic Blood Transfusion and Risk of Postoperative Complications in Patients with Mild and Moderate Anemia of Any Cause? A Retrospective Cohort Study in Total Revision Hip Surgery.

Introduction: Patients undergoing revision total hip surgery (RTHS) have a high prevalence of mild and moderate preoperative anemia, associated with adverse outcomes. The aim of this study was to investigate the association of perioperative allogeneic blood transfusions (ABT) and postoperative complications in preoperatively mild compared to moderate anemic patients undergoing RTHS who did not receive a diagnostic anemia workup and treatment before surgery. Methods: We included 1,765 patients between 2007 and 2019 at a university hospital. Patients were categorized according to their severity of anemia using the WHO criteria of mild, moderate, and severe anemia in the first Hb level of the case. Patients were grouped as having received no ABT, 1-2 units of ABT, or more than 2 units of ABT. Need for intraoperative ABT was assessed in accordance with institutional standards. Primary endpoint was the compound incidence of postoperative complications. Secondary outcomes included major/minor complications and length of hospital and ICU stay. Results: Of the 1,765 patients, 31.0% were anemic of any cause before surgery. Transfusion rates were 81% in anemic patients and 41.2% in nonanemic patients. The adjusted risks for compound postoperative complication were significantly higher in patients with moderate anemia (OR 4.88, 95% CI: 1.54-13.15, p = 0.003) but not for patients with mild anemia (OR 1.93, 95% CI: 0.85-3.94, p < 0.090). Perioperative ABT was associated with significantly higher risks for complications in nonanemic patients and showed an increased risk for complications in all anemic patients. In RTHS, perioperative ABT as a treatment for moderate preoperative anemia of any cause was associated with a negative compound effect on postoperative complications, compared to anemia or ABT alone. Discussion: ABT is associated with adverse outcomes of patients with moderate preoperative anemia before RTHS. For this reason, medical treatment of moderate preoperative anemia may be considered.

Cartilage Destruction by Hemophilic Arthropathy Can Be Prevented by Inhibition of the Ferroptosis Pathway in Human Chondrocytes.

(1) Background: Around 50% of hemophilia patients develop severe arthropathy, with even subclinical hemorrhage in childhood potentially leading to intra-articular iron deposition, synovia proliferation, neoangiogenesis, and eventual damage to articular cartilage and subchondral bone. Treatments typically include coagulation factor substitution, radiosynoviorthesis, and joint replacement for advanced cases. This study aims to elucidate programmed cell death mechanisms in hemophilic arthropathy (HA) to identify novel treatments. (2) Methods: Human chondrocytes were exposed to lysed/non-lysed erythrocytes, ferroptosis inducer ML-162, cytokines (IL-1ß, TNFα), and ferric citrate, then assessed for metabolic activity, DNA content, and cell death using Alamar Blue, cyQUANT, and Sytox assays. Three-dimensional spheroids served as a cartilage model to study the effects of erythrocytes and ML-162. (3) Results: Erythrocytes caused significant cell death in 2D cultures (p < 0.001) and damaged 3D chondrocyte spheroids. Iron citrate and erythrocytes reduced chondrocyte DNA content (p < 0.001). The ferroptosis pathway was implicated in cell death, with no effects from apoptosis and necroptosis inhibitors. (4) Conclusions: This study offers insights into HA's cell death pathway, suggesting ferroptosis inhibitors as potential therapies. Further studies are needed to evaluate their efficacy against the chronic effects of HA.

Outcomes and Return-to-Sports Rates in Patients With Borderline Hip Dysplasia After Periacetabular Osteotomy: A Case Series With 5-Year Follow-up.

BACKGROUND: The optimal surgical approach in patients with borderline hip dysplasia (BHD) remains controversial. Both hip arthroscopy and periacetabular osteotomy (PAO) are commonly employed in this patient population. Those who participate in sports want to resume and maintain sports activities after surgery, and the ability to do so plays an important role in the choice of a treatment method. To our knowledge, no previous study has assessed return-to-sports rates and activity levels in patients with BHD after PAO. PURPOSE: To assess return-to-sports rates and postoperative activity levels as measured by the University of California, Los Angeles (UCLA), activity scale as well as patient-reported outcome measures. Also to assess changes in sports activity both qualitatively and quantitatively as well as underlying reasons for these changes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We conducted a retrospective analysis of prospectively collected data from 55 hips in 52 patients with BHD who underwent PAO between January 2015 and June 2017. Return-to-sports rates, UCLA activity scores, International Hip Outcome Tool-12 scores, Subjective Hip Value scores, Hip disability and Osteoarthritis Outcome Score subscores, sports practiced, frequency and duration of sports activity, and postoperative changes as well as underlying reasons were recorded. RESULTS: The mean follow-up was 62.8 ± 9.0 months. The return-to-sports rate among preoperatively active patients was 92.5%. Most patients resumed sports activity after 6 months (50%) or after 3 to 6 months (37.5%). The UCLA activity score improved significantly (from 5.2 ± 2.4 to 7.0 ± 1.8; P < .001). The International Hip Outcome Tool-12, Subjective Hip Value, and Hip disability and Osteoarthritis Outcome Score scores also improved significantly (all, P < .001). Changes in sports activity occurred in 34.5% of cases after PAO. Significantly more patients engaged in low-impact sports postoperatively. Participation in high-impact sports did not decrease significantly. Reasons for changes were both hip related and non-hip related. Quantitatively, patients were able to significantly increase both the frequency (P = .007) and duration (P = .007) of sports activity. CONCLUSION: The return-to-sports rate in patients with BHD after PAO was high at over 92%. Most patients returned to sports after a period of 6 months or 3 to 6 months. Overall, activity levels and hip function improved after PAO. A number of patients adjusted their sports activity after PAO. Although more patients engaged in low-impact sports, participation in high-impact sports was maintained postoperatively. The results of this study may help both patients and orthopaedic surgeons in deciding on the best surgical procedure in the setting of BHD.

Periacetabular osteotomy for symptomatic hip dysplasia in middle aged patients: does age alone matter?

BACKGROUND: Conflicting evidence exists regarding outcomes in middle-aged patients undergoing periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip (DDH). AIMS: To compare patient reported outcomes (PROMs) of middle-aged PAO patients with younger patient groups. METHODS: Retrospective analysis of prospectively collected data of PAO patients between 01/2015 and 06/2017 at a single orthopedic university center with a primary diagnosis of symptomatic DDH. The cohort was divided into four age groups and compared: < 20, 20-30, 30-40 and > 40 years. Joint function was assessed using iHOT-12, mHHS and SHV. Activity level was assessed using UCLA Activity score. Patient satisfaction and pain were assessed on the numerical rating scale 0-10. Conversion rates to THA were assessed. RESULTS: Out of 202 PAOs, 120 cases with complete data were included. Mean follow-up was 63 months (range 47-81 months). Eighteen patients were < 20 years old, 54 were 20-30 years, 37 were 30-40 years, 11 patients were older than 40. No significant differences were observed for preoperative or postoperative iHOT-12 (p = 0.898; p = 0.087), mHHS (p = 0.878; p = 0.103), SHV (p = 0.602; p = 0.352) or UCLA (p = 0.539; p = 0.978) between groups. Improvement deltas were also not significantly different for all PROMs. Postoperative patient satisfaction was similar between groups (p = 0.783). CONCLUSION: Patients with symptomatic DDH may benefit from PAO even at middle age with similar outcomes and pre- to postoperative improvements as younger age groups. Indication should be based on biological age and preoperative joint condition rather than age.

Gram negative periprosthetic hip infection: nearly 25% same pathogen infection persistence at a mean of 2 years.

PURPOSE: While gram negative (GN) periprosthetic joint infections (PJI) have previously been described as difficult to treat pathogens with high rates of reinfection, limited investigations have addressed midterm outcomes and risk of infection persistence by the same pathogen. This study analyzed (1) baseline demographics, treatment strategy, and midterm outcomes of GN PJIs, as well as (2) differences in reinfection and relapse rates compared to gram positive (GP) PJIs. METHODS: We identified 29 patients that were revised for 30 GN PJIs of total hip arthroplasties (THAs) between 2010 and 2020 using a university-based hip registry. Mean age was 77 years, 63% were females (19), and mean BMI was 27 kg/m2. Major causative pathogens included Escherichia coli (12), Klebsiella pneumoniae (5), Pseudomonas aeruginosa (5), and Enterobacter cloacae complex (5). Mean follow-up was 3.5 years. Study outcomes included (1) Kaplan-Meier survivorship analyses of all 30 GN PJIs, and (2) comparison of 18 two-stage exchanges for GN PJIs and 104 two-stage exchanges for GP PJIs, performed during the time from 2013 to 2017. RESULTS: (1) The 5-year survivorship free of recurrent PJI was 69%, and there were 7 recurrent PJIs at a mean of 2 years. There were 2 further suprafascial wound infections, resulting in a 61% survivorship free of any infection at 5-years. At a mean of 2 years, there were 7 patients with reinfection by the same GN pathogen (6 PJIs, one wound infection) as at index revision (23%). (2) Following two-stage exchange, the 5-year survivorship free of recurrent PJI (GN: 74%; GP: 91%; p = 0.072), any infection (GN: 61%; GP: 91%; p = 0.001), and reinfection by the same pathogen was significantly lower among GN PJIs (GN: 73%; GP: 98%; p < 0.001). CONCLUSIONS: Patients revised for GN PJIs are at increased risk of reinfection as opposed to GP infections. Affected patients must be counseled on the exceptionally high risk of infection persistence with one in four developing relapses. LEVEL OF EVIDENCE: Therapeutic Level III.

Psychological status affects postoperative quality of life, function, and pain after periacetabular osteotomy.

Aims: Psychological status may be an important predictor of outcome after periacetabular osteotomy (PAO). The aim of this study was to investigate the influence of psychological distress on postoperative health-related quality of life, joint function, self-assessed pain, and sports ability in patients undergoing PAO. Methods: In all, 202 consecutive patients who underwent PAO for developmental dysplasia of the hip (DDH) at our institution from 2015 to 2017 were included and followed up at 63 months (SD 10) postoperatively. Of these, 101 with complete data sets entered final analysis. Patients were assessed by questionnaire. Psychological status was measured by Brief Symptom Inventory (BSI-18), health-related quality of life was raised with 36-Item Short Form Survey (SF-36), hip functionality was measured by the short version 0f the International Hip Outcome Tool (iHOT-12), Subjective Hip Value (SHV), and Hip Disability and Outcome Score (HOS). Surgery satisfaction and pain were assessed. Dependent variables (endpoints) were postoperative quality of life (SF-36, HOS quality of life (QoL)), joint function (iHOT-12, SHV, HOS), patient satisfaction, and pain. Psychological distress was assessed by the Global Severity Index (GSI), somatization (BSI Soma), depression (BSI Depr), and anxiety (BSI Anx). Influence of psychological status was assessed by means of univariate and multiple multivariate regression analysis. Results: In multiple multivariate regression, postoperative GSI, BSI Soma, and BSI Depr had a negative effect on postoperative SF-36 (e -2.07, -3.05, and -2.67, respectively; p < 0.001), iHOT-12 (e -1.35 and -4.65, respectively; p < 0.001), SHV (e -1.20 and -2.71, respectively; p < 0.001), HOS QoL (e -2.09 and -4.79, respectively; p < 0.001), HOS Function (e -1.00 and -3.94, respectively; p < 0.001), and HOS Sport (e -1.44 and -5.29, respectively; p < 0.001), and had an effect on postoperative pain (e 0.13 and 0.37, respectively; p < 0.001). Conclusion: Psychological distress, depression, and somatization disorders affect health-related quality of life, perceived joint function, and sports ability. Pain perception is significantly increased by somatization. However, patient satisfaction with surgery is not affected.

Periacetabular Osteotomy with a Modified Fixation Technique Using K-Wires Shows Clinical Results Comparable to Screw Fixation at Mid-Term Follow-Up.

BACKGROUND: The optimal fixation technique in periacetabular osteotomy (PAO) remains controversial. Modified fixation with Kirschner wires (K-wires) was described as a feasible and safe alternative. However, clinical follow-up of patients treated with this technique is lacking. AIMS: To assess patient-reported outcomes (PROMs) in patients treated with PAO with the K-wire fixation technique and to compare it with the screw fixation technique. METHODS: We conducted an analysis of 202 consecutive PAOs at a single university center between January 2015 and June 2017. A total of 120 cases with complete datasets were included in the final analysis. PAOs with K-wire fixation (n = 63) were compared with screw fixation (n = 57). Mean follow-up was 63 ± 10 months. PROMs assessed included the International Hip Outcome Tool (iHOT 12), Subjective Hip Value (SHV), and UCLA activity score (UCLA). Pain and patient satisfaction (NRS) were evaluated. Joint preservation was defined as non-conversion to total hip arthroplasty (THA). RESULTS: Preoperative baseline PROMs in both fixation groups were similar. In both groups, PROMs (p = <0.001) and pain (p = <0.001) improved significantly. Postoperative functional outcome was similar in both groups: iHOT 12 (71.8 ± 25.1 vs. 73 ± 21.1; p = 0.789), SHV (77.9 ± 21.2 vs. 82.4 ± 13.1; p = 0.192), UCLA (6.9 ± 1.6 vs. 6.9 ± 1.9; p = 0.909), and pain (2.4 ± 2.1 vs. 2.0 ± 2.1; p = 0.302). Patient satisfaction did not differ significantly (7.6 ± 2.6 vs. 8.2 ± 2.2; p = 0.170). Conversion to THA was low in both groups (two vs. none; p = 0.497). CONCLUSION: Periacetabular osteotomy with K-wire fixation provided good clinical results at mid-term follow-up, comparable to those of screw fixation. The technique can therefore be considered a viable option when deciding on the fixation technique in PAO.

Is Elective Total Hip Arthroplasty Safe in Nonagenarians?: An Arthroplasty Registry Analysis.

BACKGROUND: An increasing number of elderly patients are becoming candidates for elective total hip arthroplasty (THA). Conflicting results exist with regard to the safety of THA in nonagenarians. The aims of this study were to evaluate postoperative mortality and morbidity after THA in nonagenarians and underlying risk factors. We hypothesized that nonagenarians undergoing elective THA would show higher morbidity than younger patients and higher mortality than nonagenarians in the general population. METHODS: This was an observational cohort study using data from the German Arthroplasty Registry (Endoprothesenregister Deutschland [EPRD]). Of 323,129 THAs, 263,967 (including 1,859 performed on nonagenarians) were eligible. The mean follow-up (and standard deviation) was 1,070 ± 641 days (range, 0 to 3,060 days). The exclusion criteria were age of <60 years at admission and nonelective THAs or hemiarthroplasties. The cohort was divided into 4 age groups: (1) 60 to 69 years, (2) 70 to 79 years, (3) 80 to 89 years, and (4) ≥90 years. Comorbidities representing independent risk factors for postoperative complications and mortality were identified via a logistic regression model. Mortality rates were compared with those from the general population with data from the Federal Statistical Office. The end points of interest were postoperative major complications, minor complications, and mortality. RESULTS: Among the greatest risk factors for major and minor complications and mortality were congestive heart failure, pulmonary circulation disorders, insulin-dependent diabetes, renal failure, coagulopathy, and fluid and electrolyte disorders. Compared with younger groups, the risks of major and minor complications and mortality were significantly higher in nonagenarians. Mortality increased when major complications occurred. After 1 year, the survival rate in patients without a major complication was 94.4% compared with 79.8% in patients with a major complication. The mortality rates of nonagenarians in the study population were lower than those in the corresponding age group of the general population. The 1-year mortality rates at 90 years of age were 10.5% for men and 6.4% for women within the study group compared with 18.5% for men and 14.7% for women among the general population. CONCLUSIONS: Comorbidities favor the occurrence of complications after elective THA in nonagenarians and thus increase postoperative morbidity. In the case of complications, mortality is also increased. The fact that mortality is still lower than within the general population shows that this aspect can be controlled by careful patient selection and adequate preparation. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Intraoperative Periprostehtic Femur Fracture - When is the Cerclage Enough? / Intraoperative periprothetische Femurfrakturen ­ wann reicht die Cerclage?

BACKGROUND AND PLANNING: Intraoperative periprosthetic femoral fractures are among the most serious complications in both primary and revision arthroplasty. They are often not detected, despite intraoperative radiological control. Since an unnoticed intraoperative fracture often requires revision surgery, which has been associated with increased mortality rates, intraoperative diagnosis and corresponding direct and sufficient treatment are crucial. There are patient-, surgery-, and implant-specific risk factors that increase the possibilities of intraoperative fractures. The most common risk factors on the patient side are age, gender, and various pre-existing conditions, such as osteoporosis or rheumatic diseases. A minimally invasive approach and a cementless press-fit fixation are the most significant surgery- and implant-specific risk factors. The Vancouver classification or the modified Mallory classification are available for the classification of intraoperative periprosthetic femoral fractures. Based on these classifications, treatment recommendations can be derived. Different strategies are available for fracture management. THERAPY: Generally, if the stem is stable, osteosynthesis can be performed with preservation of the implant. This procedure can be applied to the majority of cases with non-displaced fractures by using cerclages as fixation. An unstable implant may require replacement of the stem. In higher grade fractures, stabilisation by using plate osteosynthesis may be necessary. The aim is to achieve the most anatomical reposition possible for the best possible bony consolidation. The ultimate goal is high implant stability and restoration of the biomechanics.

SARS-CoV-2 specific plasma cells acquire long-lived phenotypes in human bone marrow.

BACKGROUND: SARS-CoV-2 specific antibody-secreting plasma cells (PC) mediating specific humoral immunity have been identified in the human bone marrow (BM) after COVID-19 or vaccination against SARS-CoV-2. However, it remained unclear whether or not they acquire phenotypes of human memory plasma cells. METHODS: SARS-CoV-2-specific human bone marrow plasma cells (BMPC) were characterised by tetramer-based, antigen-specific flow cytometry and FluoroSpot assay. FINDINGS: SARS-CoV-2 spike-S1-specific PC were detectable in all tested BM samples of previously vaccinated individuals, representing 0.22% of total BMPC. The majority of SARS-CoV-2-specific BMPC expressed IgG and their specificity for the spike S1 protein indicated emergence from a systemic vaccination response. Of note, one-fifth of SARS-CoV-2-specific BMPC showed the phenotype of memory plasma cells, i.e., downregulated CD19 and present or absent CD45 expression. INTERPRETATION: Our data indicate the establishment of phenotypically diverse SARS-CoV-2-specific PC in the human BM after basic mRNA immunization, including the formation of memory phenotypes. These results suggest the induction of durable humoral immunity after basic mRNA vaccination against SARS-CoV-2. FUNDING: The study was supported by funding by the DFG grants TRR130 TP24, ME 3644/8-1, and the Berlin Senate. SR received funding from DFGSFB-1444 C01 Central Service Project.

The influence of lumbo-sacral transitional vertebrae in developmental dysplasia of the hip: a matched pair analysis.

Lumbo-sacral transitional vertebrae (LSTV) are the most common congenital alteration of the lumbo-sacral junction and known to significantly influence pelvic anatomy. However, the influence of LSTV on dysplasia of the hip (DDH) and the surgical treatment by periacetabular osteotomy (PAO) remains unknown. We retrospectively examined standardized standing anterior-posterior pelvic radiographs of 170 patients in 185 PAO procedures. Radiographs were examined for LSTV, lateral-central-edge-angle (LCEA), Tönnis-angle (TA), femoral-head-extrusion index (FHEI), and anterior-wall-index (AWI) and posterior-wall-index (PWI). Patients with LSTV were compared to an age- and sex-matched control group. Patient-reported outcome measurements (PROMs) were evaluated pre- and in the mean 63.0 months (range 47-81 months) postoperatively. 43 patients (25.3%) had LSTV. Patients with LSTV had significantly greater PWI (p = 0.025) compared to the matched control group. No significant differences were seen in AWI (p = 0.374), LCEA (p = 0.664), TA (p = 0.667), and FHEI (p = 0.886). Between the two groups, no significant differences were detected in pre- or postoperative PROMs. Due to the increased dorsal femoral head coverage in patients with LSTV and DDH compared to patients with sole DDH, a more pronounced ventral tilting might be performed in those patients with prominent posterior wall sign to avoid anterior undercoverage, which is a significant predictor for premature conversion to hip arthroplasty after PAO. However, anterior overcoverage or acetabular retroversion must be avoided due to the risk of femoroacetabular impingement. Patients with LSTV reported similar functional outcomes and activity after PAO as the control group. Therefore, even for patients with concomitant LSTV, which are frequent with one-fourth in our cohort, PAO is an efficient treatment option to improve clinical symptoms caused by DDH.

[Fixation techniques in periacetabular osteotomy : Stability and clinical aspects of established and new fixation techniques]. / Fixationstechniken bei periazetabulärer Osteotomie : Stabilität und klinische Aspekte etablierter und neuer Fixationstechniken.

Periacetabular osteotomy according to Ganz (PAO) is an established technique for the surgical treatment of hip dysplasia with the aim of biomechanically optimizing the dysplastic hip joint. Through multidimensional reorientation, the deficient coverage of the femoral head can be improved and physiological values can be achieved. Until bony consolidation is reached, adequate fixation of the acetabulum in the corrected position achieved is necessary. Various fixation techniques are available for this purpose. Alternatively to screws, Kirschner wires can also be used for fixation. The different fixation techniques show comparable stability. Differences exist in the occurrence of implant-associated complications. However, there is no difference in patient satisfaction and joint-specific function.

Periprosthetic hip infection in octogenarians : a single institution experience of 33 cases.

AIMS: Periprosthetic joint infection (PJI) in total hip arthroplasty in the elderly may occur but has been subject to limited investigation. This study analyzed infection characteristics, surgical outcomes, and perioperative complications of octogenarians undergoing treatment for PJI in a single university-based institution. METHODS: We identified 33 patients who underwent treatment for PJIs of the hip between January 2010 and December 2019 using our institutional joint registry. Mean age was 82 years (80 to 90), with 19 females (57%) and a mean BMI of 26 kg/m2 (17 to 41). Mean American Society of Anesthesiologists (ASA) grade was 3 (1 to 4) and mean Charlson Comorbidity Index was 6 (4 to 10). Leading pathogens included coagulase-negative Staphylococci (45%) and Enterococcus faecalis (9%). Two-stage exchange was performed in 30 joints and permanent resection arthroplasty in three. Kaplan-Meier survivorship analyses were performed. Mean follow-up was five years (3 to 7). RESULTS: The two-year survivorship free of any recurrent PJI was 72% (95% confidence interval (CI) 56 to 89; 18 patients at risk). There were a total of nine recurrent PJIs at a mean of one year (16 days to eight years), one for the same pathogen as at index infection. One additional surgical site infection was noted at two weeks, resulting in a 69% (95% CI 52 to 86; 17 patients at risk) survivorship free of any infection at two years. There were two additional revisions for dislocations at one month each. As such, the two-year survivorship free of any revision was 61% (95% CI 42 to 80; 12 patients at risk). In addition to the aforementioned revisions, there was one additional skin grafting for a decubitus ulcer, resulting in a survivorship free of any reoperation of 54% (95% CI 35 to 73; ten patients at risk) at two years. Mean Clavien-Dindo score of perioperative complications was two out of five, with one case of perioperative death noted at six days. CONCLUSION: Octogenarians undergoing surgery for PJI of the hip are at low risk of acute mortality, but are at moderate risk of other perioperative complications. One in two patients will undergo a reoperation within two years, with 70% attributable to recurrent infections.Cite this article: Bone Joint J 2023;105-B(2):135-139.

Association of age and spinopelvic function in patients receiving a total hip arthroplasty.

Restricted spinopelvic mobility received attention as a contributing factor for total hip arthroplasty (THA) instability. However, it is still unknown, how the spinopelvic function is influenced by age. In identifying the patients at highest risk for altered spinopelvic mechanics the study aimed to determine the association of age on the individual segments of the spinopelvic complex and global spinal sagittal alignment in patients undergoing THA. 197 patients were included in the prospective observational study conducting biplanar stereoradiography (EOS) in standing and sitting position pre-and postoperatively. Two independent investigators assessed C7-sagittal vertical axis (C7-SVA), cervical lordosis (CL), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), anterior plane pelvic tilt (APPT), and pelvic femoral angle (PFA). Key segments of the spinopelvic complex are defined as lumbar flexibility (∆ LL = LLstanding - LLsitting), pelvic mobility (∆ SS = SSstanding - SSsitting) and hip motion (∆ PFA = PFAstanding - PFAsitting). Pelvic mobility was further defined based on ∆ SS = SSstanding - SSsitting as stiff (∆ SS < 10°), normal (∆ SS ≥ 10°-30°) and hypermobile (∆ SS > 30°). The patient collective was classified into three groups: (1) < 60 years (n = 56), (2) ≥ 60-79 years (n = 112) and (3) ≥ 80 years (n = 29). Lumbar flexibility (∆ LL) was decreased with increasing age between all groups (36.1° vs. 23.1° vs. 17.2°/p1+2 < 0.000, p2+3 = 0.020, p1+3 < 0.000) postoperatively. Pelvic mobility (∆ SS) was decreased in the groups 2 and 3 compared to group 1 (21.0° and 17.9° vs. 27.8°/p1+2 < 0.000, p2+3 = 0.371, p1+3 = 0.001). Pelvic retroversion in standing position (APPT) was higher in group 2 and 3 compared to group 1 (1.9° and - 0.5° vs 6.9°/p1+2 < 0.000, p2+3 = 0.330, p1+3 < 0.000). Global sagittal spinal balance (C7-SVA) showed more imbalance in groups 2 and 3 compared to group 1 (60.4 mm and 71.2 mm vs. 34.5 mm/p1+2 < 0.000, p2+3 = 0.376, p1+3 < 0.000) postoperatively. The preoperative proportion of patients with stiff pelvic mobility in group 1 was distinctly lower than in group 3 (23.2% vs. 35.7%) and declined in group 1 to 1.8% compared to 20.7% in group 3 after THA. Changes after THA were reported for groups 1 and 2 representing spinopelvic complex key parameter lumbar flexibility (∆ LL), pelvic mobility (∆ SS) and hip motion (∆ PFA), but not for group 3. This is the first study to present age-adjusted normative values for spinopelvic mobility. The subgroups with increased age were identified as risk cohort for altered spinopelvic mechanics and enhanced sagittal spinal imbalance and limited capacity for improvement of mobility after THA. This valuable information serves to focus in the preoperative screening on the THA candidates with the highest risk for abnormal spinopelvic function.

Periprosthetic knee infection in octogenarians: a single institution experience at midterm outcome.

PURPOSE: Periprosthetic joint infections (PJI) of total knee arthroplasties (TKAs) in the elderly is among the clinically most challenging scenarios given multimorbidity combined with poor bone and soft tissue quality. Despite increasing prevalence, limited is known on PJI among this unique group of patients. As such, this study analyzed PJI characteristics, implant survivorship and non-surgical complications of octogenarians revised PJI for the knee. METHODS: We identified 31 patients that were revised for PJIs of the knee between 2010 and 2019 using a single university-based registry. Mean age was 83 years (range 80-87), 48% were females, and mean BMI was 29 kg/m2. Mean age adjusted Charlson Comorbidity Index was 7, and mean ASA score was 3. Major causative pathogens included Coagulase-negative Staphylococci (26%), Staphylococcus aureus (13%), and Streptococci (13%). Two-stage exchange was performed in 30 patients, permanent resection arthroplasty in one joint. Kaplan-Meier survivorship analyses were performed. Mean follow-up was 4 years. RESULTS: The 2-year survivorship free of any recurrent PJI was 96%, and there was one PJI relapse noted at 6 months. Moreover, there were three additional revisions for aseptic loosening, and one further revision for fracture. As such, the 2-year survivorship free of any revision was 87%. In addition to the aforementioned revisions, there was one additional plate osteosynthesis for a Vancouver C fracture, resulting in a 79% survivorship free of any reoperation at 2 years. Mean perioperative complication score according to the Clavien-Dindo classification was 2 out of 5. A total of three patients died: one patient 40 days after resection arthroplasty, two others 4 months and 8 months after reimplantation. CONCLUSIONS: Octogenarians revised for PJI of the knee are at low risk of recurrent infection and overall revision at 2 years. However, moderate rates of perioperative complications and mortality at short term must acknowledge before deciding upon procedure. LEVEL OF EVIDENCE: Therapeutic level IV.

Changes in Sports Activity After Periacetabular Osteotomy: A Qualitative and Quantitative Analysis.

BACKGROUND: Patients undergoing periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip are usually young and active with high functional demands. Those who participate in sports seek surgical therapy to resume or maintain sports activities. There is little evidence regarding the postoperative level of activity and the extent to which sports activity changes after PAO both qualitatively and quantitatively. PURPOSE: The aim of this study was to determine the change in activity level as measured using the University of California Los Angeles (UCLA) activity score and the changes in qualitative and quantitative sports activity. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: This was a retrospective analysis of prospectively collected data of 123 hips in 111 patients who underwent PAO for developmental dysplasia of the hip between January 2015 and June 2017. UCLA activity score, International Hip Outcome Tool 12, and Subjective Hip Value, as well as practiced sports, frequency and duration of sports activity, and time to return to sports, were assessed. Eventual changes in practiced sports and reasons for those changes were recorded. RESULTS: Of the participating patients, 85% were female and 15% were male. The mean patient age at the time of surgery was 27.7 ± 7.3 years. Mean follow-up was 63 ± 10 months. UCLA score (5.08 ± 2.44 vs 6.95 ± 1.74; P < .001), International Hip Outcome Tool 12 (41.4 ± 22.2 vs 72.6 ± 22.9; P < .001), and Subjective Hip Value (42.8 ± 24.3 vs 80.4 ± 17.8; P < .001) increased significantly from pre- to postoperatively. Significantly more patients participated in low-impact sports postoperatively (31.7% vs 52%; P = .001). Participation in high-impact sports decreased (42.3% vs 36.6%; P = .361). The overall sports activity rate increased significantly (78.8% vs 90.8%; P = .008). Quantitatively, sports frequency in times per week (P < .001) as well as length of exercise per time (P = .007) increased significantly. A total of 52 patients (42%) changed sports activities postoperatively. Of these, 35 (28.4%) reported having stopped previously practiced sports after surgery, while 17 (13.8%) reported having started new sports. Reasons for starting and stopping certain sports varied and included hip- and non-hip related ones. In only 2 cases was physician's advice given as a reason for changing the sport. CONCLUSION: Patients can improve their sports activity both qualitatively and quantitatively after PAO. However, a relevant proportion of patients adjusts their sports activities for a variety of hip-related and non-hip related reasons.