NOS inhibition reverses TLR2-induced chondrocyte dysfunction and attenuates age-related osteoarthritis.

Osteoarthritis (OA) is a joint disease featuring cartilage breakdown and chronic pain. Although age and joint trauma are prominently associated with OA occurrence, the trigger and signaling pathways propagating their pathogenic aspects are ill defined. Following long-term catabolic activity and traumatic cartilage breakdown, debris accumulates and can trigger Toll-like receptors (TLRs). Here we show that TLR2 stimulation suppressed the expression of matrix proteins and induced an inflammatory phenotype in human chondrocytes. Further, TLR2 stimulation impaired chondrocyte mitochondrial function, resulting in severely reduced adenosine triphosphate (ATP) production. RNA-sequencing analysis revealed that TLR2 stimulation upregulated nitric oxide synthase 2 (NOS2) expression and downregulated mitochondria function-associated genes. NOS inhibition partially restored the expression of these genes, and rescued mitochondrial function and ATP production. Correspondingly, Nos2-/- mice were protected from age-related OA development. Taken together, the TLR2-NOS axis promotes human chondrocyte dysfunction and murine OA development, and targeted interventions may provide therapeutic and preventive approaches in OA.

Synovial fluid D-lactate - a pathogen-specific biomarker for septic arthritis: a prospective multicenter study.

OBJECTIVES: The performance of synovial fluid biomarker D-lactate to diagnose septic arthritis (SA) and differentiate it from crystal-induced arthritis (CA), other non-infectious rheumatic joint diseases (RD) and osteoarthrosis (OA) was evaluated. METHODS: Consecutive adult patients undergoing synovial fluid aspiration due to joint pain were prospectively included in different German and Swiss centers. Synovial fluid was collected for culture, leukocyte count and differentiation, detection of crystals, and D-lactate concentration. Youden's J statistic was used to determine optimal D-lactate cut-off value on the receiver operating characteristic (ROC) curve by maximizing sensitivity and specificity. RESULTS: In total 231 patients were included. Thirty-nine patients had SA and 192 aseptic arthritis (56 patients with OA, 68 with CA, and 68 with RD). The median concentration of synovial fluid D-lactate was significantly higher in patients with SA than in those with OA, CA, and RD (p<0.0001, p<0.0001 and p<0.0001, respectively). The optimal cut-off of synovial fluid D-lactate to diagnose SA was 0.033 mmol/L with a sensitivity of 92.3 % and specificity of 85.4 % independent of previous antimicrobial treatment. Sensitivity and specificity of synovial fluid leukocyte count at a cut-off of 20,000 cells/µL was 81.1 % and 80.8 %, respectively. CONCLUSIONS: Synovial fluid D-lactate showed a high performance for diagnosing SA which was superior to synovial fluid leukocyte count. Given its high sensitivity and specificity, it serves as both an effective screening tool for SA and a differentiator between SA and RD, especially CA.

Accurate surgical posterior tibial slope alteration can be achieved in total knee arthroplasty regardless of surgeon skill level or local soft tissue thickness-A retrospective radiograph-based study.

PURPOSE: To retrospectively report on the impact of local soft tissue thickness and surgeon skill level on the accuracy of surgical posterior tibial slope (PTS) alteration achieved in patients undergoing total knee arthroplasty (TKA) utilising lateral knee radiographs. METHODS: Pre- and postoperative radiographs of 82 patients undergoing primary TKA using conventional mechanical alignment technique were measured by two observers and subjected to quality criteria for accurate measurement of the PTS. All patients underwent a standardised surgical approach for PTS alteration: cruciate-retaining (CR) cases with preoperative PTS ≤ 10° were set for reconstruction of the preoperative PTS. Cases indicated for posterior-stabilised (PS) design and/or with a preoperative PTS > 10° were set for 3° of postoperative PTS. Pretibial subcutaneous fat (PSF) and surgeon skill level were analysed for their predictive quality regarding the accuracy of surgical PTS alteration achieved. RESULTS: The overall mean postoperative PTS was significantly lower than the preoperative values (6.2°, SD 2.7 vs. 7.7°, SD 3.2; p = 0.002103). Neither local soft tissue thickness, namely PSF, nor surgeon skill level was found to be a predictor of the accuracy of surgical PTS alteration achieved. Among cases set for PTS reconstruction, 25.9% and 42.6% achieved a postoperative PTS within ±1° and ±2° of preoperative values, respectively. In patients with a PTS > 10° or those indicated for PS design, slope reduction was achieved with a mean postoperative PTS of 6.5°. Furthermore, 14.3% and 32.1% of cases were within ±1° and ±2° of 3, respectively. CONCLUSION: This study demonstrates that accurate surgical alteration of the PTS is possible in TKA regardless of local knee soft tissue thickness or surgeon skill level. This proves the clinical feasibility of both targeted reduction as well as reconstruction of the PTS in TKA. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

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.

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.

Identifying Critical Evidence Gaps in Wound Closure and Incision Management After Total Knee Arthroplasty: Delphi Panel Insights.

BACKGROUND: Effective surgical wound management in total knee arthroplasty (TKA) is crucial for optimal healing and patient outcomes. Despite surgical advances, managing wounds to prevent complications remains challenging. This study aimed to identify and address evidence gaps in TKA wound management, including preoperative optimization, intraoperative options, and postoperative complication avoidance. Addressing these issues is vital for patient recovery and surgical success. METHODS: This study used the Delphi method with 20 experienced orthopedic surgeons from Europe and North America. Conducted from April to September 2023, the process involved three stages: an initial electronic survey, a virtual meeting, and a concluding electronic survey. The panel reviewed and reached a consensus on 26 statements about TKA wound management based on a comprehensive literature review. Additionally, the panel aimed to identify critical evidence gaps in wound management practices. RESULTS: The panel achieved consensus on various wound management practices but highlighted significant evidence gaps. Consensus was reached on wound closure methods, including mesh-adhesive dressings, skin glue, staples, barbed sutures, and negative pressure wound therapy. However, further evidence is needed to address the cost-effectiveness of these methods and develop best practices for patient outcomes. Identifying these gaps highlights the need for more research to improve TKA wound care. CONCLUSIONS: Identifying major evidence gaps underscores the need for targeted research in TKA wound management. Addressing these gaps is crucial for developing effective, efficient, and patient-friendly wound care strategies. Future research should focus on comparative effectiveness studies and developing guidelines for emerging technologies. Bridging these gaps could improve patient outcomes, reduce complications, and enhance TKA surgery success.

International Delphi Study on Wound Closure and Dressing Management in Joint Arthroplasty: Part 1: Total Knee Arthroplasty.

BACKGROUND: The purpose of this modified Delphi study was to obtain consensus on wound closure and dressing management in total knee arthroplasty (TKA). METHODS: The Delphi panel included 20 orthopaedic surgeons from Europe and North America. There were 26 statements identified using a targeted literature review. Consensus was developed for the statements with up to three rounds of anonymous voting per topic. Panelists ranked their agreement with each statement on a five-point Likert scale. An a priori threshold of ≥ 75% was required for consensus. RESULTS: All 26 statements achieved consensus after three rounds of anonymous voting. Wound closure-related interventions that were recommended for use in TKA included: 1) closing in semi-flexion versus extension (superior range of motion); 2) using aspirin for venous thromboembolism prophylaxis over other agents (reduces wound complications); 3) barbed sutures over non-barbed sutures (lower wound complications, better cosmetic appearances, shorter closing times, and overall cost savings); 4) mesh-adhesives over other skin closure methods (lower wound complications, higher patient satisfaction scores, lower rates of readmission); 5) silver-impregnated dressings over standard dressings (lower wound complications, decreased infections, fewer dressing changes); 6) in high-risk patients, negative pressure wound therapy over other dressings (lower wound complications, decreased reoperations, fewer dressing changes); and 7) using triclosan-coated over non-antimicrobial-coated sutures (lower risks of surgical site infection). CONCLUSIONS: Using a modified Delphi approach, the panel achieved consensus on 26 statements pertaining to wound closure and dressing management in TKA. This study forms the basis for identifying critical evidence supported by clinical practice for wound management to help reduce variability, advance standardization, and ultimately improve outcomes during TKA. The results presented here can serve as the foundation for knowledge, education, and improved clinical outcomes for surgeons performing TKAs.

International Delphi Study on Wound Closure and Incision Management in Joint Arthroplasty Part 2: Total Hip Arthroplasty.

BACKGROUND: This modified Delphi study aimed to develop a consensus on optimal wound closure and incision management strategies for total hip arthroplasty (THA). Given the critical nature of wound care and incision management in influencing patient outcomes, this study sought to synthesize evidence-based best practices for wound care in THA procedures. METHODS: An international panel of 20 orthopedic surgeons from Europe, Canada, and the United States evaluated a targeted literature review of 18 statements (14 specific to THA and 4 related to both THA and total knee arthroplasty). There were 3 rounds of anonymous voting per topic using a modified 5-point Likert scale with a predetermined consensus threshold of ≥ 75% agreement necessary for a statement to be accepted. RESULTS: After 3 rounds of voting, consensus was achieved for all 18 statements. Notable recommendations for THA wound management included (1) the use of barbed sutures over non-barbed sutures (shorter closing times and overall cost savings); (2) the use of subcuticular sutures over skin staples (lower risk of superficial infections and higher patient preferences, but longer closing times); (3) the use of mesh-adhesives over silver-impregnated dressings (lower rate of wound complications); (4) for at-risk patients, the use of negative pressure wound therapy over other dressings (lower wound complications and reoperations, as well as fewer dressing changes); and (5) the use of triclosan-coated sutures (lower risk of surgical site infection) over standard sutures. CONCLUSIONS: Through a structured modified Delphi approach, a panel of 20 orthopedic surgeons reached consensus on all 18 statements pertaining to wound closure and incision management in THA. This study provides a foundational framework for establishing evidence-based best practices, aiming to reduce variability in patient outcomes and to enhance the overall quality of care in THA procedures.

Bilateral simultaneous knee arthroplasty shows comparable early outcome and complication rate as staged bilateral knee arthroplasty for patients scored ASA 1-3 if performed by a high-volume surgeon: a retrospective cohort study of 127 cases.

BACKGROUND AND PURPOSE: The study compares early outcomes after simultaneous and staged knee arthroplasty in patients with bilateral knee osteoarthritis (OA) to evaluate whether simultaneous bilateral TKA shows comparable early outcomes and complication rates to staged bilateral TKA. METHODS: A retrospective cohort study including all patients scheduled for primary TKA for bilateral knee OA (n = 127) was conducted. Patients received either simultaneous (n = 53, 41.7%) or staged (n = 74, 58.3%) bilateral TKA by a single, high-volume surgeon-depending on their individual preference. Demographic data, haemoglobin drop (Hb), length of stay (LOS), operation time, 30-day complication rate and achievement of rehabilitation key points were evaluated. RESULTS: There was no difference between the groups concerning age, sex, BMI or complication rate. ASA scoring was better in the simultaneous group [2.2, (15.1% ASA 1, 49.1% ASA 2, 35.8% ASA 3) vs. 2.4 (2.7% ASA 1, 51.4% ASA 2, 45.9% ASA 3)]. Average LOS was 7.8 ± 2.1 days for simultaneous TKA, 7.4 ± 1.7 days for single procedure of staged group (p < 0.453) and 14.7 ± 3.1 days if combined (p < 0.001). Cumulative Hb loss was significantly higher in the staged group (3.8 ± 1.2 g/dl vs. 2.4 ± 0.8 g/dl, p < 0.001). Detailed comparison of early outcome parameters between staged and simultaneous procedure depending on ASA score only revealed slightly slower assessment of stairs (p < 0.001) and increased Hb drop per surgery in case of simultaneous procedure (p < 0.011) if ASA score was ≥ 2. Only patients scored ASA 3 demonstrated a significant longer LOS per procedure in simultaneous group (8.5 ± 2.4 vs.7.3 ± 1.6 days, p = 0.034). INTERPRETATION: Simultaneous bilateral TKA results in comparable early outcome and complication rate than staged bilateral procedure-even for patients scored ASA 3. LEVEL OF EVIDENCE: Level IV.

The need for state-of-the-art orthopedic surgical technology in low- to middle income countries : The case of distraction epiphyseolysis for limb lengthening in children with fibular hemimelia in Uzbekistan.

INTRODUCTION: Amongst low- to middle income countries (LMIC), outdated and poorly documented orthopedic interventions may pose patients at risk for complications, serious adverse events (SAE) and unsatisfactory results, contradicting the World Health Organization's (WHO) Safe Surgery mandates. Use cases of conditions managed inadequately in LMIC environments are necessary to increase awareness of stakeholders and overcome deficiencies in collaboration with high-income countries (HIC). MATERIALS AND METHODS: Methodological and clinical experts from the BG Kliniken and the Charité, Berlin, Germany, were invited to investigate established processes for musculoskeletal disorders and injuries in Tashkent, Uzbekistan. Congenital lower leg discrepancy due to fibular hemimelia was recognized as an illustrative example to prove the effectiveness of local treatment guidelines, still relying on distraction epiphyseolysis (chondrodiatasis) via an Ilizarov frame. Routine data from hospital records, images and outpatient follow-up examinations were compared to estimates from a review of studies of limb-lengthening by other techniques. RESULTS: Data from 16 of 49 immature patients (10 males, 6 females, mean age at surgery, 4.2 ± 2.3 years) undergoing chondrodiatasis between 2017 and 2021 showed a mean limb elongation of 2.4 (95% confidence interval [CI], 1.9 to 2.9) cm after a median follow-up of 29 (range, 24 to 36) months. While no complications or SAE were noted, findings are compatible with a risk of 21% under an upper 97.5% confidence limit for null events. No reproducible classification of hemimelia, surgical or general complications, assessment of functional outcomes or health-related quality of life were available. The pooled average length gain from 21 studies on different other interventions with osteotomy enrolling 458 limbs was 5.1 (95% CI, 5.0 to 5.3) cm. CONCLUSIONS OF THE USE CASE: Limb lengthening for hereditary fibular hemimelia in Uzbekistan revealed rather obsolete surgical algorithms, inadequate documentation, and unreliable outcome assessment. Resource limitations notwithstanding, knowledge transfer, implementation of current procedures and hardware, and international collaboration is vital to improve quality of care in this scenario and for the benefit of LMIC in general.

Recovery of muscular tissue and functional results of patients treated with a gluteus maximus flap transfer due to chronic abductor deficiency after total hip arthroplasty.

BACKGROUND: To evaluate the function of the abductor mechanism after a gluteus maximus flap transfer due to a degeneration of the muscles after hip arthroplasty, we analyzed the post-operative functional outcome as well as radiographic effects in muscle tissue. METHODS: This present study included six consecutive patients operatively treated with a gluteus maximus flap due to chronic gluteal deficiency after total hip arthroplasty. All patients presented a preoperative severe limp, hip abductor deficiency and a history of conservative treatment without the relief of symptoms. MRI scans were performed pre- and postoperatively to evaluate the muscle volume and grade of degeneration of the abductor mechanism. For clinical evaluation, the Harris hip score (HHS) was applied pre- and postoperatively. Moreover, the intensity of pain, the Trendelenburg sign, the internal rotation lag sign and the abductor muscle force were measured before and after surgery. RESULTS: Overall, the evaluation of the Magnetic Resonance Imaging (MRI) showed no significant changes in total muscle volume during the follow-up period. Separate measurements presented a significant growth of muscle volume for the gluteus minimus and tensor fascia lata compared to preoperative imaging during the follow-up period. The amount of fat volume decreased for all the measured muscles with statistical significance for the gluteus minimus, the gluteus medius and the tensor fascia lata. No further muscle degeneration and no flap necrosis were measured. The postoperative HHS results were not statistically significant compared to the preoperative results. CONCLUSIONS: Besides fair clinical results, the radiological measurements indicate that the flap transfer enables functional muscular tissue recovery and prevents further degeneration. Given these conditions, the gluteus maximus muscle flap transfer represents a viable treatment option for patients with chronic gluteal deficiency in selected patients.

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.

Resident memory CD4+ T lymphocytes mobilize from bone marrow to contribute to a systemic secondary immune reaction.

Resident memory T lymphocytes (TRM ) of epithelial tissues and the Bm protect their host tissue. To what extent these cells are mobilized and contribute to systemic immune reactions is less clear. Here, we show that in secondary immune reactions to the measles-mumps-rubella (MMR) vaccine, CD4+ TRM are mobilized into the blood within 16 to 48 h after immunization in humans. This mobilization of TRM is cognate: TRM recognizing other antigens are not mobilized, unless they cross-react with the vaccine. We also demonstrate through methylome analyses that TRM are mobilized from the Bm. These mobilized cells make significant contribution to the systemic immune reaction, as evidenced by their T-cell receptor Vß clonotypes represented among the newly generated circulating memory T-cells, 14 days after vaccination. Thus, TRM of the Bm confer not only local, but also systemic immune memory.

Functional gait analysis reveals insufficient hindfoot compensation for varus and valgus osteoarthritis of the knee.

PURPOSE: The hindfoot is believed to compensate varus and valgus deformities of the knee by eversion and inversion movements. But these mechanisms were merely found in static radiologic measurements. The aim of this study was, therefore, to assess dynamic foot posture during gait using pressure-sensitive wireless insoles in patients with osteoarthritis of the knee and frontal knee deformities. METHODS: Patients with osteoarthritis of the knee were prospectively included in this study. Patients were clinically and radiologically (mechanical tibiofemoral angle (mTFA), hindfoot alignment view angle (HAVA), and talar tilt (TT)) exa mined. Gait line analysis was conducted using pressure-sensitive digital shoe insoles. RESULTS: Eighty-two patients (varus n = 52, valgus n = 30) were included in this prospective clinical study. Radiologically, the mTFA significantly correlated with the HAVA (cor = -0.72, p < 0.001) and with the TT (Pearson's cor = 0.32, p < 0.006). Gait analysis revealed that the gait lines in varus knee osteoarthritis were lateralized, despite the hindfoot valgus. In valgus knee osteoarthritis, gait lines were medialized, although the hindfoot compensated by varization. CONCLUSIONS: Functional dynamic gait analysis could demonstrate that the hindfoot is not able to sufficiently compensate for frontal malalignments of the knee joint, contrary to static radiologic findings. This led to a narrowing of the joint space of the ankle medially in varus and laterally in valgus knee osteoarthritis.

Bilateral simultaneous hip arthroplasty shows comparable early outcome and complication rate as staged bilateral hip arthroplasty for patients scored ASA 1-3 if performed by a high-volume surgeon.

PURPOSE: The aim of this study was to compare early outcomes after simultaneous and staged hip arthroplasty (THA) in patients with bilateral symptomatic pathology. METHODS: We conducted a retrospective cohort study including all patients scheduled for primary THA for bilateral hip osteoarthritis (OA, n = 290). Patients either received simultaneous (n = 152, 52.4%) or staged (n = 138, 47.6%) bilateral THA based on individual preference. All operations (n = 428) were performed by one single, high-volume surgeon. Demographic data (e.g., age, ASA score) as well as perioperative parameters (haemoglobin drop (Hb), red blood cell transfusion, length of stay (LOS), operation time, six week complication rate and achievement of inpatient rehabilitation key points) were evaluated. RESULTS: Patients in the simultaneous bilateral THA group were younger (62.8 ± 8.9 vs. 65 ± 9.7 years, p = 0.022) and had lower ASA scores (1.8, (34.2% ASA 1, 55.3% ASA 2, 37.2% ASA 3) vs. 2.0 (18.8% ASA 1, 61.6% ASA 2, 19.6% ASA 3)) than the staged group. While the average LOS was 7.1 ± 1.7 days for simultaneous bilateral THA, the combined LOS for the staged group was 12.9 ± 2.4 days (p < 0.001). The cumulative operation time in the simultaneous bilateral THA group was 61.1 ± 11.5 min and 57.6 ± 7.3 min in the staged group (p < 0.015). Cumulative Hb loss was significantly higher in the staged group (2.1 ± 7.2 g/dl vs. 3.7 ± 1.3 g/dl, p < 0.001). No significant differences were found concerning the complication rate or early inpatient rehabilitation. CONCLUSION: Simultaneous bilateral hip arthroplasty in patients with symptomatic bilateral hip osteoarthritis is as safe and successful as a staged procedure if performed by a high-volume surgeon.

Allografts: expanding the surgeon's armamentarium.

In Germany, bone allografts are widely used and their application in clinics has increased over the years. Successful use of allografts depends on many factors such as the procurement, processing, sterilization and the surgeon's surgical experience. Tissue banks have provided safe and sterile allografts for decades ranging from hard to soft tissue. Allografts are obtained from various tissues such as bone, tendon, amniotic membrane, meniscus and skin. An advantage of allografts is their wide applicability that has never been limited by indication restrictions thus providing a huge benefit for surgeon's. The use of the correct allograft in different indications is extremely important. Thereby surgeons have access to various allograft forms such as mineralized, demineralized, freeze-dried, paste, powder, chips strips and putty. The vast options of allografts allow surgeon's to use allografts in indications they deem fit. Currently, the application of allografts is at the discretion of the expert surgeon. However, regulations are often changed locally or internationally and may impact/limit allograft use to certain indications. Here, we report the different indications where our peracetic acid (PAA) sterilised bone allografts were used as well as general literature on bone allograft use in other indications.

Chondrocyte Isolation from Loose Bodies-An Option for Reducing Donor Site Morbidity for Autologous Chondrocyte Implantation.

Loose bodies (LBs) from patients with osteochondritis dissecans (OCD) are usually removed and discarded during surgical treatment of the defect. In this study, we address the question of whether these LBs contain sufficient viable and functional chondrocytes that could serve as a source for autologous chondrocyte implantation (ACI) and how the required prolonged in vitro expansion affects their phenotype. Chondrocytes were isolated from LBs of 18 patients and compared with control chondrocyte from non-weight-bearing joint regions (n = 7) and bone marrow mesenchymal stromal cells (BMSCs, n = 6) obtained during primary arthroplasty. No significant differences in the initial cell yield per isolation and the expression of the chondrocyte progenitor cell markers CD44 + /CD146+ were found between chondrocyte populations from LBs (LB-CH) and control patients (Ctrl-CH). During long-term expansion, LB-CH exhibited comparable viability and proliferation rates to control cells and no ultimate cell cycle arrest was observed within 12 passages respectively 15.3 ± 1.1 mean cumulative populations doublings (CPD). The chondrogenic differentiation potential was comparable between LB-CH and Ctrl-CH, but both groups showed a significantly higher ability to form a hyaline cartilage matrix in vitro than BMSC. Our data suggest that LBs are a promising cell source for obtaining qualitatively and quantitatively suitable chondrocytes for therapeutic applications, thereby circumventing donor site morbidity as a consequence of the biopsies required for the current ACI procedure.

The role of biopsy in diagnosing infection after hip and knee arthroplasty: a meta-analysis.

INTRODUCTION: Early diagnosis of periprosthetic hip and knee infection still represents a major challenge, as no single test can achieve ideal results. Currently, multiple preoperative indicators were performed to diagnose periprosthetic joint infection (PJI) to confirm or exclude infection in the early stage. However, the diagnostic value of biopsy-related tests in diagnosing periprosthetic hip and knee infection remains unclear. MATERIALS AND METHODS: Publications in PubMed, Embase, and the Web of Science databases were searched systematically until October 2020. Inclusion and exclusion criteria were used for screening biopsy-related studies of the diagnosis of periprosthetic hip and knee infection. RESULTS: Three biopsy-related tests were identified in 14 articles and further analyzed in the present meta-analysis. The combined method had the highest value for the area under the curve (0.9805), followed by histology (0.9425) and microbiological tests (0.9292). In the subgroup, statistical differences were identified in sensitivity and specificity for PJI diagnosis between the synovial fluid culture and biopsy culture group, as well as in the biopsy-related combined method and serum C-reactive protein. CONCLUSIONS: Biopsy culture does not appear to be advantageous compared to synovial fluid culture in the preoperative diagnosis of periprosthetic hip and knee infection. In contrast, combined biopsy microbial culture with histology analysis shows great potential in improving the preoperative diagnosis of PJI. The standard procedure of biopsy needs to be further explored. Further research is required to verify our results.

Mechanical failure of total hip arthroplasties and associated risk factors.

INTRODUCTION: Mechanical failure of total hip arthroplasties is a rare but devastating complication. With increasing numbers in primary arthroplasty implantation, revision surgeries are indicated more often. Therefore, understanding the mechanism and the location of failure is essential in determining proper treatment. Aim of this study was to identify mechanical failures of all total hip arthroplasties performed in a major academic center as well as the associated risk factors such as BMI and sports. METHODS: A retrospective trial was conducted using our prospective arthroplasty database. Database was searched for all patients presenting with mechanical failures of total hip arthroplasty (THA) to the emergency department between 2011 and 2019. All medical charts and radiographs as well as surgical reports were analyzed to identify demographics, implant choice in addition to location of failure and subsequent treatment. RESULTS: In total, 13 patients suffering from mechanical total hip implant failure were found. The femoral neck (conus) was broken in four patients, the stem in five cases, one broken inlay, two cup failures and one conus dislocation. The mean BMI was 31.42 ± 5.29 kg/m2 including five patients who have obesity class II. In all cases, revision surgeries were indicated. No structural causes or underlying risk factors such as repeated physical load (i.e. in sports) were identified. CONCLUSION: Implant failure does not seem to correlate with participation in sports or BMI. Catastrophic failure of implants is a technical challenge requiring special extraction instruments that can be difficult even for experienced surgeons. It should be noted that functional outcome is often worse for this group of patients after surgery than comparing against those revised for loosening. LEVEL OF EVIDENCE: III, Retrospective Trial.

Two-stage exchange for PJI with co-existing cerclages for fracture: higher rates of early re-infections and difficult to treat microbes.

INTRODUCTION: Periprosthetic joint infections (PJI) with osteosynthesis material for contemporaneous fractures are a challenging, yet poorly described condition. This study will analyze PJI with co-existing fractures treated with cerclages and two-stage exchange. MATERIALS AND METHODS: Patients with and without cerclages for coexisting periprosthetic fractures, undergoing two-stage exchange for PJI of hip or knee, between 06/2013 and 02/2016, were compared concerning baseline characteristics and re-infection rate in the course of a 2 year follow-up. All patients were treated with a standardized two-stage protocol. A PJI was defined according to the EBJIS criteria. All foreign material, including cerclages, was sent in for sonication for microbiological analysis. RESULTS: Ninety-six patients treated with two-stage exchange for PJI could be included. Co-existing fractures treated with cerclage were identified in nine patients (9.3%, study group). Diaphyseal femoral simple in five cases (AO2A3) and proximal intertrochanteric in three cases (AO1A3) were the leading fracture locations. In one patient, cerclage implantation was performed prior to prosthesis explantation, in six, during prosthesis explantation, and in two, in the course of prosthesis reimplantation. The study group showed a significantly higher rate of difficult to treat microbes (44.4%; 8.0%; p = .001), Charlson Comorbidity Index (5.4; 3.7; p = .033), relapse infections with the same microbe (22.2%; 1.1%; p = .001), and early-onset infections (< 30 days) (11.1%; 1.1%; p = .046), than the comparison two-stage exchange group without fractures. In contrast, age (72.5 study group; 68.2 comparison group; p = .224), rate of revisions for PJI in the past (55.5%; 51.7%; p = .827), and total re-infection rate (22.2%; 10.3%; p = .287) did not show a difference. CONCLUSION: PJI with co-existing cerclages for fractures were associated with multi-resistant microbes, relapse by the same microbe and early-onset re-infections. Cerclages might be considered a potential source of re-infection during a two-stage exchange. However, statistical weaknesses and a small study group must be considered limitations of the study.