BACKGROUND:Chondral lesions of the hip in young, active patients are a recognised cause of pain, functional limitation, and early osteoarthritis. Although regenerative cartilage repair techniques are well established in the knee, hip-specific evidence remains limited. This systematic review and meta-analysis evaluated clinical outcomes and predictors of success following surgical and biologically augmented treatments for hip cartilage lesions. METHODS:A systematic search of PubMed, OVID MEDLINE, and EBSCOHost was conducted in December 2024 to identify prospective and retrospective case series and comparative studies reporting outcomes following surgical or biologic interventions. Functional outcome was primarily assessed using the modified Harris Hip Score (mHHS), and failure was defined as conversion to total hip arthroplasty (THA). Random-effects meta-regression was used to evaluate predictors of endpoint mHHS and change-from-baseline mHHS (ΔmHHS), while failure outcomes were analysed using Kaplan-Meier survival analysis and Cox proportional hazards regression. 27 studies comprising 30 intervention arms and 1059 patients were included. RESULTS:Cell-based and scaffold-assisted techniques, including autologous chondrocyte implantation, matrix-induced autologous chondrocyte implantation, autologous matrix-induced chondrogenesis, and micro-fragmented adipose tissue transplantation, demonstrated the highest adjusted endpoint mHHS values (>87). In contrast, microfracture and commercial fibrin glue were associated with inferior functional outcomes and higher THA conversion rates (7.1-12.9%). Meta-regression identified intervention type as the primary determinant of outcome, with increasing defect size independently associated with poorer endpoint mHHS. Improvements in ΔmHHS were influenced by age, defect size, and follow-up duration, although findings were limited by potential model overfitting. Survival analyses demonstrated high overall THA-free survivorship, with increasing age emerging as the consistent predictor of failure. CONCLUSIONS:Biological restoration techniques appear to outperform reparative strategies for short-term functional outcomes in hip cartilage lesions. Intervention type, defect size, and patient age remain key determinants of success, underscoring the need for high-quality comparative studies with long-term follow-up.PROSPERO registration:CRD420250644934.

Aims This study examines the ability of YOLO (You Only Look Once) 11x, a widely used and state of the art object detection model, trained on publicly available datasets, to identify and count neutrophils in tissue samples taken at prosthetic joint revision surgery, with the objective of automating a laborious but necessary part of the diagnostic workup for periprosthetic joint infection. Methods Three datasets containing blood film microscopic slides with neutrophils were downloaded, combined, and labelled. The resulting dataset of 3,923 images was augmented with ten additional histological slides from periprosthetic tissue, taken at the time of revision surgery (5 infected, 5 sterile), and split into training (70%), validation (20%), and test (10%) sets. The dataset was used to train YOLO 11x object detection model optimized for a mean average precision above 50%. The trained network was tested on a ground truth specimen and histological whole slide images from 19 additional cases, previously unseen by the model, for validation. The threshold for diagnosis of infection on histological sections was set at more than five neutrophils per 0.2 mm2 (equivalent to one high-powered microscope field). Results The model performed well as ground truth image returned precision at 82%, recall (sensi tivity) 79%, and F1 harmonic mean 80%. When assessed against formal histopathological, microbiological, and multidisciplinary team (MDT) diagnosis, precision was 78%, 80%, and 90%; recall 78%, 89%, and 82%; and F1 score 78%, 84%, and 86%, respectively. Against the definitive MDT diagnosis, our model identified nine out of the ten infected cases and excluded seven out of nine cases that were not infected.- Conclusion This study demonstrates ability of the trained model to identify neutrophils in tissue taken at revision surgery and could assist in diagnosis of periprosthetic infection. Further work is needed to improve confidence in the identifications and diagnostic accuracy of peripros thetic infection.-

Synovial fluid is a clinically valuable biofluid for studying joint diseases through metabolomic analysis. However, given the viscoelastic nature of this biofluid its analysis is challenging. Indeed, the lack of standardised pre-analytical processing protocols for synovial fluid metabolomics potentially introduces significant variability that can compromise data reliability and hinder the application/interpretation of results. This study systematically assesses how common sample handling variables including sample dilution, freeze-thaw cycling, blood staining and viscosity reduction (via hyaluronidase digestion and bead beating) affect the metabolomic profile of synovial fluid. Using a combination of untargeted GC-ToF-MS and UHPLC-MS (in both electrospray ionisation modes; ESI+ and ESI-) for the profiling of both polar and non-polar metabolites, we evaluated changes in detectable metabolite numbers, small molecule class distribution and relative abundances in a collection of synovial fluid samples. Sample dilution had the most pronounced impact on metabolite read-outs, significantly reducing detectable metabolite numbers. Blood staining introduced distinct metabolites and resulted in the artificial increase in the relative abundance of three metabolites including adenine, hypoxanthine and 4-fluoro-DL-tryptophan. Bead beating enhanced the detection of a broad range of lipid species particularly in the UHPLC ESI+ analysis. Freeze-thaw cycling and hyaluronidase treatment had minimal effects on overall metabolite quantities or composition. These findings underscore the importance of optimising and standardising synovial fluid sample handling to ensure reproducibility and to enable accurate interpretation of metabolomic data for the study of disease mechanisms and biomarker discovery.

Mesenchymal stromal cell extracellular vesicles (MSC EVs) hold great therapeutic potential. Their immunomodulatory abilities make them suitable candidates to treat autoimmune diseases, such as rheumatoid arthritis. However, MSC EV production must be reproducibly scaled to meet the demand of research and therapeutics. To achieve this, four human umbilical cord MSC (UC-MSC) donors were pooled, a method known to generate a large cell source, that averages heterogeneous cell attributes. Upon generating MSC EV enrichments, donor pooling proved advantageous by increasing EV yield, both by increasing particle number and the presence of EV defining characteristics. Protein analysis suggests this could be due to an upregulation of protein transport mechanisms but requires further work to confirm. When applied to an inflammatory model of arthritis, pooled UC-MSC EV enrichments surpassed their parental cells and single donor UC-MSC EV enrichments, in alleviating arthritic pathophysiology, albeit the particle input was doubled since this was normalised by cell number. Therefore, we propose donor pooling as a simple and effective method to generate MSC EV enrichments, with potential to increase EV production without compromising therapeutic efficacy.

Introduction Autologous conditioned plasma (ACP) is a single-spin, leukocyte-poor platelet-rich plasma (PRP) that provides a plasma with a platelet concentration 2 to 3 times the blood platelet concentration. The objective of this study was to investigate the clinical effectiveness of ACP intra-articular injection in patients with knee osteoarthritis (OA) and to identify any demographic, disease-associated, or biological predictors of outcome. Methods A prospective cohort study was conducted between 2022 and 2023 in a single high-volume tertiary center, including 42 patients (54 knees) who consented to be enrolled. Patients underwent a series of 3 injections of ACP at weekly intervals, prepared using the Arthrex ACP Double-Syringe System. Lysholm scores were collected at baseline, 3-months, and 6-months post-injection. Results Forty patients (49 knees) completed the follow-up and were included in the final analysis. The mean age was 53.8 ± 10.16 years (range 35-76 years), and the median body mass index (BMI) was 29 (interquartile range [IQR]: 27-34). There were 22 females and 18 males. Treatment failure occurred in 12 out of 49 cases (24.49%). The mean platelet concentration in the ACP was 588.5 ± 183.2 × 10 6 /ml, with a mean platelet fold increase of 2.14 ± 0.71 compared to the baseline. Multi-linear regression modeling showed that older age and higher mean platelet concentration were predictors of higher post-injection Lysholm scores, with beta coefficients of 0.34 and 0.28, respectively, and p values of 0.013 and 0.036, respectively. Conclusion Autologous conditioned plasma provided clinical benefits in this cohort study of knee OA patients for at least 6 months post-injection. Older age and a higher mean platelet concentration in the ACP were identified as predictors of a higher Lysholm score.

Background/Objectives: The diagnosis of prosthetic joint infection remains difficult. Microbiological cultures frequently have false-positive and false-negative results. This study investigates whether rapid nanopore sequencing can be used to aid the identification of bacteria causing prosthetic joint infection for more timely identification and treatment. Methods: Nineteen patients who had revision surgery following total joint arthroplasty were included in this study. Of these, 15 patients had an infected joint arthroplasty. All patients had joint fluid aspirated at the time of revision surgery. The DNA was extracted from these fluid aspirates, and rapid nanopore sequencing was performed using the MinION device from Oxford Nanopore Technologies. The sequencing data was trimmed to improve quality and filtered to remove human reads using bioinformatic tools. Genomic sequence classification was performed using the Basic Local Alignment Search Tool. The results were filtered by read length and sequence identity score. The European Bone and Joint Infection Society criteria were used as a standard to identify infected and not infected patients. Confusion tables were used to calculate accuracy and F1 score based on this criteria and the nanopore sequencing results. Results: Microbiological cultures and nanopore sequencing had an accuracy of 68% and 74%, respectively. However, combining both results predicted infection accurately in 94% of cases (F1 score 96%). Conclusions: Nanopore sequencing has the potential to aid identification of bacteria causing prosthetic joint infection and may be useful as a supplementary diagnostic tool.

Introduction Bone marrow aspirate concentrate (BMAC) is an autologous biological augment used in the treatment of osteochondral lesions of the talus. Several studies have reported the short-term efficacy of BMAC for repair of osteochondral lesions of the talus, however, there is minimal regulation of the autologous products' potency and “release criteria” for clinical use. Moreover, the mechanism of action of BMAC therapy is poorly understood. Objectives This study aimed to investigate the composition of BMAC and BMAC mixed with thrombin (B+T), prepared according to commercial Complete Cartilage Regeneration kit protocols, linked to functional outcome data. Methods Bone marrow aspirate, BMAC, and B+T samples (n=16) were obtained for cellular analysis via a hematology analyzer and colony-forming unit-fibroblast assay. Molecular composition was assessed via a multiplex 27-cytokine assay and enzyme-linked immunosorbent assay (n=12). Spearman rank correlation was used to assess the relationship between both cellular and molecular composition with patient functional outcomes. Results Mesenchymal stem cells and platelets were concentrated in BMAC compared with bone marrow aspirate, but were reduced significantly after addition of thrombin. Cytokines and growth factors also decreased in concentration in B+T, however, platelet-derived growth factor-BB and interleukin-1 receptor alpha were significantly increased. Basic fibroblast growth factor, Eotaxin, IL-4, and IL-17 were found to have a positive correlation with worsening Manchester-Oxford Foot and Ankle Questionnaire (MOXFQ) 7months postoperation. Conclusions This study provides insight into the cellular and molecular characteristics of BMAC and B+T, highlighting donor heterogeneity and the importance of profiling autologous products prior to treatment.

Prosthetic joint infection (PJI) is a serious complication following total joint arthroplasty (TJA) and can have devastating consequences if not treated effectively. There is no clear ‘gold standard’ for the diagnosis of PJI, current techniques include blood biochemical markers and microbiological cultures to identify the species of bacteria. Challenges associated with microbiological cultures include inaccurate results and time delays before reporting of results. In the hospital of study, samples of joint fluid and tissue are collected during surgical intervention for PJI and are sent to a partner hospital for microbiological cultures. Results are typically reported back after 7-14 days. Nanopore sequencing is a third-generation genomic sequencing technology designed to facilitate fast, inexpensive, and simple genomic sequencing. This study aims to investigate nanopore sequencing, as a quick and cost-effective method to identify the species of bacteria causing PJI from joint aspirates. Joint fluid aspirates were collected during surgical interventions for PJI. DNA was extracted from these samples and sequenced using the MinION device. Sequencing data was classified using Basic Local Alignment Search Tool (BLAST) against the bacterial database. Sequencing data was filtered by quality parameters such as Phred score. 30 samples of fluid were used for nanopore sequencing (26 PJI-positive and 4 controls), based on clinical definitions of infection. Clinical assessments included blood biochemical markers (CRP, ESR), histology, physical signs (e.g., redness, swelling) and multi-disciplinary team (MDT) decision. The MDT decision was used as the clinical decision of infection. Results from nanopore sequencing and microbiological cultures were compared with clinical assessments. Contingency tables were made to compare nanopore sequencing with the clinical assessment of patients and to compare microbiological cultures with the clinical decision of patients. Combining the results from nanopore sequencing with microbiological cultures gave an accuracy of 0.89, positive predictive value (PPV) of 0.92, recall (sensitivity) of 0.96 and F1 score of 0.94. The accuracy for microbiological cultures alone was 0.62. Nanopore sequencing shows promise as an additional test in diagnosing PJI, particularly when cultures are negative. The advantage for the use of nanopore sequencing in the diagnosis of PJI is the turn-around time of results compared to microbiological cultures. This could have implications with reducing hospital stays, length of treatment and time frames between the first and second stage of a two-stage prosthetic exchange. This may improve patient outcomes and reduced treatment costs. Further studies could solidify its role in routine PJI diagnosis.

Objective:Inflammation of the synovium (synovitis) is implicated in the onset, progression and clinical manifestation of osteoarthritis (OA), although its prevalence at different stages of the disease has yet to be definitively established. Synovial macrophages play a central role in synovitis and can demonstrate pro- and anti-inflammatory phenotypes. The pervasiveness and variation in phenotypic identity of macrophages in early- and late-OA synovia is unclear. In the present study we investigated the frequency and severity of synovitis and assessed macrophage phenotypes in synovia from patients with high risk of developing PTOA (deemed early-OA) or late-OA. Design:Synovial samples were collected from patients undergoing cell therapy treatment for early-OA or arthroplasty for late-OA. Synovitis was assessed using a semi-quantitative, histological scoring system. Macrophage abundance and phenotypic characteristics were assessed by immunohistochemistry and image analysis. Study parameters were compared between the early- and late-OA groups and correlated with demographic and clinical information. Results:Synovitis was more prevalent and generally more severe in early-OA synovia compared to late-OA synovia (effect size; d ​= ​0.76). There were more macrophages overall (d ​= ​1.04), with more demonstrating markers characteristic of a pro-inflammatory (M1) phenotype (d ​= ​0.86), in the early-OA cohort. Synovitis severity was significantly correlated with the total number of macrophages (ρ ​= ​0.47), and with the presence of both M1 (ρ ​= ​0.65) and M2 (ρ ​= ​0.49) macrophage markers (M2 typically considered to indicate an anti-inflammatory or wound-healing phenotype). Conclusions:Our data suggest that synovial inflammation may play a greater role in the early stages of OA than in end-stage disease, and is at least partly mediated by synovial macrophages.

Objective To determine the association between socioeconomic deprivation and short-term patient-reported clinical outcomes following autologous chondrocyte implantation (ACI). Design All patients receiving knee ACI between 1996 and 2020 in our center were identified. Socioeconomic deprivation of their residential area was quantified using the Index of Multiple Deprivation (IMD). Patient-reported 1-year Lysholm and Intermittent and Constant Osteoarthritis Pain (ICOAP) scores were used as outcome measures in the analyses. After transformation to ensure normal distributions (where required), linear multivariable regression was used to analyze the relationship between IMD and 1-year Lysholm score, adjusting for demographic characteristics (age, sex, body mass index [BMI], and smoking) and baseline Lysholm. Results Three hundred and ninety-one patients with a mean age of 50 years (range = 16-84; 266 male) were identified. Median BMI was 27 (17-47), with 138 patients overweight and 105 obese. Seventy-seven patients lived in upper and 41 in lower quintile deprivation areas. The mean baseline Lysholm score was 49.8 ± 17.3 SD, improving to 66.5 ± 21.3 SD at 1 year. Mean 1-year Lysholm scores were significantly lower with increasing area deprivation scores, adjusted for demographic factors. Specifically, areas with high unemployment levels, being female, or having a lower baseline Lysholm were associated with poorer outcomes, but age, BMI, smoking, or higher income deprivation were not. Conclusion This study demonstrates poorer functional outcomes following ACI in patients from more deprived areas, indicating future studies should consider neighborhood deprivation as a confounding factor. Furthermore, targeting patients from areas with higher deprivation with additional interventions/community support may improve their outcomes.

Allogeneic chondrocyte therapies present an attractive alternative to existing autologous therapies for the repair of cartilage defects, enabling the selection of optimal donor cells and streamlined manufacturing processes. This study investigates the potential of juvenile chondrocytes derived from human infantile (aged 0–4 y) polydactyly digits and the iliac apophysis for cartilage repair using Good Manufacturing Practice bioreactor expansion. Iliac apophysis (n = 4) and polydactyly tissues (n = 4) were assessed histologically. Chondrocytes were isolated enzymatically and cultured using standard tissue culture plastic (TCP) methodology. Upon sufficient cell expansion, chondrocytes were seeded into the Quantum® bioreactor system or onto TCP (±vitronectin coating). The manufactured chondrocytes growth rates, total cell yields, chondrogenic pellet forming capacity (GAG/DNA, histology), immunoprofiles (flow cytometry) and gene expression (RT-qPCR) were assessed. Equivalent chondrocyte numbers were isolated from polydactyly and iliac apophysis donors per wet weight of tissue. Quantum®-expanded chondrocytes from both sources yielded comparable cell numbers; however, growth was slowed in the Quantum® compared to TCP. Polydactyly and iliac apophysis-derived chondrocytes expressed chondrocyte cell surface markers (CD166, CD44, CD151, SOX9) and formed chondrogenic pellets. Quantum® bioreactor expansion did not alter, gene expression or capacity to form glycosaminoglycans (GAGs (normalised to DNA content)) compared to matched TCP expansion. Juvenile cartilage donors are a promising chondrocyte source for the development of an allogeneic therapy. This novel study expanding juvenile chondrocytes in the Quantum® GMP-compliant bioreactor suggests that culture conditions may need modification to improve growth, whilst retaining cartilage forming capacity.

Background Single-photon emission computerised tomography with conventional computer tomography (SPECT/CT) is an emerging technology which may hold clinical value for the identification of cartilage lesions in the knee joint. The intensity and distribution of SPECT/CT uptake tracer may identify physiological and structural information in the absence of structural change on other imaging modalities. Objectives To systematically assess the utility of SPECT/CT in the detection of chondral lesions within the knee joint, in patients presenting with knee pain, with or without structural change. Results PubMed, Science Direct, Web of Knowledge, and NHS databases were searched for English language articles focusing on the diagnostic value of SPECT/CT for knee chondral lesions and knee pain. Animal studies, cadaver studies, comparator radiological technique other than SPECT/CT or patients with a pathology other than knee chondral lesions were excluded. From the search, 11,982 manuscripts were identified, and screened for relevance. Seven studies were identified and scored low on QUADAS-2 bias review. SPECT/CT correlated with lesions found on other imaging modalities and during intraoperative assessment. Furthermore, in some cases, SPECT/CT out-performed other modalities in the detection of cartilage lesions. Conclusion Evidence suggests SPECT/CT may be a useful tool for the detection and localisation of cartilage lesions, particularly in discrepant cases when there is an absence of lesions on other imaging modalities, or a lack of correlation with patients’ symptoms. Further studies are required to confirm the conclusions of this review.

PurposeTo investigate patient demographic, injury and surgery/treatment-associated factors that can influence the patient-reported outcome (Lysholm score), following autologous chondrocyte implantation (ACI) in a large, 'real-world', nonuniform, prospective data examined retrospectively.MethodsKnee patients treated at the Robert Jones and Agnes Hunt Orthopaedic Hospital, UK, using ACI between 1996 and 2020 were eligible. All longitudinal postoperative Lysholm scores collected between 1 and 23 years after ACI treatment and before any second major procedure (e.g., arthroplasty) were included. Multilevel longitudinal models were built investigating the association of short-term (1 year) or long-term trends in Lysholm score with baseline demographic, clinical and cell-culture variables, namely age, gender, smoker status, body mass index, baseline Lysholm score, time from surgery, defect grade, diameter and location, number of defects, previous microfracture, patch/scaffold type, associated procedure(s), number of cells implanted and their passage number.ResultsFollowing filtering, 306 of the 427 knee ACI procedures reviewed were suitable for inclusion. Factors shown to result in higher postoperative Lysholm scores in the short term were lower patient age, higher baseline Lysholm scores, fewer implanted cells and a lateral femoral defect location. The factor which was associated with higher long-term postoperative Lysholm scores was a milder defect grade. Additionally, the failure rate in this cohort was explored and it was found that 73/306 (24%) of patients experienced joint failure according to our definition. Furthermore, the outcome was not influenced by coincidental procedures in this cohort of patients.ConclusionsThis study has identified a number of baseline factors associated with patient-reported outcomes following ACI and shows that treatment of associated pathology at the time of surgery potentially restores patient outcomes to a similar level as those with no associated pathologies.Level of EvidenceLevel IV.

Aims:To explore key stakeholder views around feasibility and acceptability of trials seeking to prevent post-traumatic osteoarthritis (PTOA) following knee injury, and provide guidance for next steps in PTOA trial design. Methods:Healthcare professionals, clinicians, and/or researchers (HCP/Rs) were surveyed, and the data were presented at a congress workshop. A second and related survey was then developed for people with joint damage caused by knee injury and/or osteoarthritis (PJDs), who were approached by a UK Charity newsletter or Oxford involvement registry. Anonymized data were collected and analyzed in Qualtrics. Results:Survey responses (n = 19 HCP/Rs, 39 PJDs) supported studies testing pharmacological agents preventing PTOA. All HCP/Rs and 30/31 (97%) PJDs supported the development of new treatments that improved or delayed knee symptoms and damage to knee structure. PJDs thought that improving structural knee damage was more important than knee symptoms. Both groups found studies more acceptable as expected future benefit and risk of PTOA increased. All drug delivery routes were acceptable. Workshop participants (around n = 60) reflected survey views. Discussions suggested that stratifying using molecular testing for likely drug response appeared to be more acceptable than using characteristics such as sex, age, and BMI. Conclusion:Our findings supported PTOA drug intervention studies, including situations where there is low risk of disease, no expected benefit of treatment, and frequent treatment administration. PJDs appeared less risk-averse than HCP/Rs. This work reinforces the benefits of consensus and involvement work in the co-creation of PTOA drug trial design. Involvement of key stakeholders, such as PJDs with different risks of OA and regulatory representatives, are critical for trial design success.

1.Abstract1.1.IntroductionSpinal Cord Injury (SCI) is a major cause of disability, with complications post-injury often leading to life-long health issues with need of extensive treatment. Neurological outcome post-SCI can be variable and difficult to predict, particularly in incomplete injured patients. The identification of specific SCI biomarkers in blood, may be able to improve prognostics in the field. This study has utilised proteomic and bioinformatics methodologies to investigate differentially expressed proteins in plasma samples across human SCI cohorts with the aim of identifying prognostic biomarkers and biological pathway alterations that relate to neurological outcome.1.2.Methods and MaterialsBlood samples were taken, following informed consent, from ASIA impairment scale (AIS) grade C “Improvers” (those who experienced an AIS grade improvement) and “Non-Improvers” (No AIS change), and AIS grade A and D at <2 weeks (“Acute”) and approx. 3 months (“Sub-acute”) post-injury. The total protein concentration from each sample was extracted, with pooled samples being labelled and non-pooled samples treated with ProteoMiner™ beads. Samples were then analysed using two 4-plex isobaric tag for relative and absolute quantification (iTRAQ) analyses and a label-free experiment for comparison, before quantifying with mass spectrometry. Data are available via ProteomeXchange with identifiers PXD035025 and PXD035072 for the iTRAQ and label-free experiments respectively.Proteomic datasets were analysed using OpenMS (version 2.6.0). R (version 4.1.4) and in particular, the R packages MSstats (version 4.0.1) and pathview (version 1.32.0) were used for downstream analysis. Proteins of interest identified from this analysis were further validated by enzyme-linked immunosorbent assay (ELISA).1.3.ResultsThe data demonstrated proteomic differences between the cohorts, with the results from the iTRAQ approach supporting those of the label-free analysis. A total of 79 and 87 differentially abundant proteins across AIS and longitudinal groups were identified from the iTRAQ and label-free analyses, respectively. Alpha-2-macroglobulin (A2M), retinol binding protein 4 (RBP4), serum amyloid A1 (SAA1), Peroxiredoxin 2, Apolipoprotein A1 (ApoA1) and several immunoglobulins were identified as bio-logically relevant and differentially abundant, with potential as individual prognostic biomarkers of neurological outcome. Bioinformatics analyses revealed that the majority of differentially abundant proteins were components of the complement cascade and most interacted directly with the liver.1.4.ConclusionsMany of the proteins of interest identified using proteomics were detected only in a single group and therefore have potential as a binary (present or absent) biomarkers, RBP4 and PRX-2 in particular. Additional investigations into the chronology of these proteins, and their levels in other tissues (cerebrospinal fluid in particular) are needed to better understand the underlying pathophysiology, including any potentially modifiable targets. Pathway analysis highlighted the complement cascade as being significant across groups of differential functional recovery.