Posttraumatic osteoarthritis: a first estimate of incidence, prevalence, and burden of disease

Lifetime risk and genetic predisposition to post-traumatic OA of the knee in the UK Biobank

OBJECTIVE

Acute knee injury is associated with post-traumatic OA (PTOA). Very little is known about the genome-wide associations of PTOA when compared with idiopathic OA (iOA). Our objective was to describe the development of knee OA after a knee injury and its genetic associations in UK Biobank (UKB).

DESIGN

Clinically significant structural knee injuries in those ≤50 years were identified from electronic health records and self-reported data in 502,409 UKB participants. Time-to-first knee osteoarthritis (OA) code was compared in injured cases and age-/sex-matched non-injured controls using Cox Proportional Hazards models. A time-to-OA genome-wide association study (GWAS) sought evidence for PTOA risk variants 6 months to 20 years following injury. Evidence for associations of two iOA polygenic risk scores (PRS) was sought.

RESULTS

Of 4233 knee injury cases, 1896 (44.8%) were female (mean age at injury 34.1 years [SD 10.4]). Over a median of 30.2 (IQR 19.5-45.4) years, 1096 (25.9%) of injured cases developed knee OA. The overall hazards ratio (HR) for knee OA after injury was 1.81 (1.70,1.93), P = 8.9 × 10-74. Female sex and increasing age at injury were associated with knee OA following injury (HR 1.15 [1.02,1.30];1.07 [1,07,1.07] respectively). OA risk was highest in the first 5 years after injury (HR 3.26 [2.67,3.98]), persisting for 40 years. In 3074 knee injury cases included in the time-to-OA GWAS, no variants reached genome-wide significance. iOA PRS was not associated with time-to-OA (HR 0.43 [0.02,8.41]).

CONCLUSIONS

Increasing age at injury and female sex appear to be associated with future development of PTOA in UKB, the risk of which was greatest in the 5 years after injury. Further international efforts towards a better-powered meta-analysis will definitively elucidate genetic similarities and differences of PTOA and iOA.

Oxidative stress as a key modulator of cell fate decision in osteoarthritis and osteoporosis: a narrative review

During aging and after traumatic injuries, cartilage and bone cells are exposed to various pathophysiologic mediators, including reactive oxygen species (ROS), damage-associated molecular patterns, and proinflammatory cytokines. This detrimental environment triggers cellular stress and subsequent dysfunction, which not only contributes to the development of associated diseases, that is, osteoporosis and osteoarthritis, but also impairs regenerative processes. To counter ROS-mediated stress and reduce the overall tissue damage, cells possess diverse defense mechanisms. However, cellular antioxidative capacities are limited and thus ROS accumulation can lead to aberrant cell fate decisions, which have adverse effects on cartilage and bone homeostasis. In this narrative review, we address oxidative stress as a major driver of pathophysiologic processes in cartilage and bone, including senescence, misdirected differentiation, cell death, mitochondrial dysfunction, and impaired mitophagy by illustrating the consequences on tissue homeostasis and regeneration. Moreover, we elaborate cellular defense mechanisms, with a particular focus on oxidative stress response and mitophagy, and briefly discuss respective therapeutic strategies to improve cell and tissue protection.

Effects of low-intensity exercise on spontaneously developed knee osteoarthritis in male senescence-accelerated mouse prone 8

BACKGROUND

Osteoarthritis (OA) is a degenerative joint disease associated with aging, which often leads to joint stiffness and disability. Exercise is one of the most important non-pharmacological treatments and is prescribed as an indispensable treatment for OA. However, whether physical exercise is beneficial for preventing the progression of OA symptoms with age is poorly understood. We investigated the effects of exercise on spontaneously developed knee OA using male senescence-accelerated mouse prone 8 (SAMP8).

METHODS

To examine age-related changes in the knee joints of SAMP8, knee articular cartilage changes, synovitis, knee joint flexion and extension angles, swelling, walking ability, and quadriceps muscle atrophy were analyzed at 3, 5, 7, and 9 months. SAMP8 were required to run at a speed of 10 m/min for 15 min/day from 7 to 9 months of age. The knee joint pathologies and symptoms of exercising and non-exercising mice were compared by histological, immunohistochemical, and morphometrical analyses.

RESULTS

The mice presented with various histological changes, including cartilage destruction, osteocyte formation, synovitis, declined joint angles, and swelling. Notably, medial and posterior cartilage destruction was more severe than that of the lateral and anterior cartilage. Knee joint angles were significantly correlated with the histological scores (modified Mankin and OARSI, osteophyte formation and synovial lining cell layer). Exercise did not attenuate cartilage degeneration in the medial and posterior tibial plateau, although the articular cartilage of the anterior and lateral tibial plateau and its histological scores was remained and significantly improved, respectively, by exercise. Exercise suppressed the age-related decline of collagen type II-positive areas in the remaining articular cartilage and improved the OA symptoms. Exercise reduced the expression of monocyte chemoattractant protein (MCP)-1 and tumor necrosis factor (TNF)-α positive macrophages in the synovium.

CONCLUSION

This study revealed that SAMP8 developed spontaneous knee OA with age, which resembled the disease symptoms in humans. Low-intensity exercise temporarily alleviated degeneration of the remaining cartilage, synovitis, and age-related decreases in knee flexion angle, stride length, and muscle atrophy in SAMP8. However, exercise during OA progression with age may cause mechanical stress that could be both beneficial and detrimental to joint health.

Effect of Targeted Cytokine Inhibition on Progression of Post-Traumatic Osteoarthritis Following Intra-Articular Fracture

Intra-articular fractures (IAF) result in significant and prolonged inflammation, increasing the chances of developing post-traumatic osteoarthritis (PTOA). Interleukin-one beta (IL-1β) and Tumor Necrosis Factor-alpha (TNF-α) are key inflammatory factors shown to be involved in osteochondral degradation following IAF. As such, use of targeted biologics such as Infliximab (INX), a TNF-α inhibitor, and Anakinra (ANR), an interleukin-one (IL-1) receptor antagonist (IL1RA), may protect against PTOA by damping the inflammatory response to IAF and reducing osteochondral degradation. To test this hypothesis, IAFs were induced in the hindlimb knee joints of rats treated with INX at 10 mg/kg/day, ANR at 100 g/kg/day, or saline (vehicle control) by subcutaneous infusion for a period of two weeks and healing was evaluated at 8-weeks post injury. Serum and synovial fluid (SF) were analyzed for soluble factors. In-vivo microcomputed tomography (µCT) scans assessed bone mineral density and bone morphometry measurements. Cationic CA4+ agent assessed articular cartilage composition via ex vivo µCT. Scoring according to the Osteoarthritis Research Society International (OARSI) guidelines was performed on stained histologic tibia sections at the 56-day endpoint on a 0-6 scale. Systemically, ANR reduced many pro-inflammatory cytokines and reduced osteochondral degradation markers Cross Linked C-Telopeptide Of Type II (CTXII, p < 0.05) and tartrate-resistant acid phosphatase (TRAP, p < 0.05). ANR treatment resulted in increased chemokines; macrophage-chemotractant protein-1 (MCP-1), MPC-3, macrophage inhibitory protein 2 (MIP2) with a concomitant decrease in proinflammatory interleukin-17A (IL17A) at 14 days post-injury within the SF. Microcomputed tomography (µCT) at 56 days post-injury revealed ANR Treatment decreased epiphyseal degree of anisotropy (DA) (p < 0.05) relative to saline. No differences were found with OARSI scoring but contrast-enhanced µCT revealed a reduction in glycosaminoglycan content with ANR treatment. These findings suggest targeted cytokine inhibition, specifically IL-1 signaling, as a monotherapy has minimal utility for improving IAF healing outcomes but may have utility for promoting a more permissive inflammatory environment that would allow more potent disease modifying osteoarthritis drugs to mitigate the progression of PTOA after IAF.

Is radiographic osteoarthritis associated with pain and disability of the ankle?

Objective

Ankle osteoarthritis (OA) is relatively understudied. It often affects younger people compared to OA in other joints. Evidence on the association between radiographic OA and ankle symptoms remains contradicting. We therefore examined the association of degree of radiographic talocrural, subtalar and talonavicular OA with severity of ankle pain, disability and predominant symptoms.

Method

A cross-sectional study was conducted in a radiology department serving primary and secondary care. From the total study population (adults referred for ankle radiography), patients with chronic ankle complaints were selected (N ​= ​231). Before radiography, participants completed a questionnaire on severity of ankle pain and disability using the Ankle Osteoarthritis Scale (AOS), and on their predominant symptoms, i.e. pain, functional loss, stiffness and/or instability. To assess the associations of the Kellgren-Lawrence scores (0, 1 or ≥2) with the primary outcomes (AOS), linear regression, and with the secondary outcomes predominant symptoms, logistic regression analyses were applied.

Results

Radiographic OA was not associated with AOS-pain and -disability. Radiographic talocrural OA was associated with functional loss (OR 3.26, 95% CI: 1.31; 8.11). A positive trend was seen between radiographic talonavicular OA and stiffness (OR 2.63, 95% CI: 0.97; 7.15).

Conclusion

The presence of radiographic OA is not associated with severity of ankle pain and disability in patients with chronic ankle complaints referred for ankle radiography. However, radiographic talocrural OA is associated with functional loss and radiographic talonavicular OA with stiffness as predominant symptom. These findings may contribute to better recognition of ankle OA in clinical practice.

Secretive derived from hypoxia preconditioned mesenchymal stem cells promote cartilage regeneration and mitigate joint inflammation via extracellular vesicles

Secretome derived from mesenchymal stem cells (MSCs) have profound effects on tissue regeneration, which could become the basis of future MSCs therapies. Hypoxia, as the physiologic environment of MSCs, has great potential to enhance MSCs paracrine therapeutic effect. In our study, the paracrine effects of secretome derived from MSCs preconditioned in normoxia and hypoxia was compared through both in vitro functional assays and an in vivo rat osteochondral defect model. Specifically, the paracrine effect of total EVs were compared to that of soluble factors to characterize the predominant active components in the hypoxic secretome. We demonstrated that hypoxia conditioned medium, as well as the corresponding EVs, at a relatively low dosage, were efficient in promoting the repair of critical-sized osteochondral defects and mitigated the joint inflammation in a rat osteochondral defect model, relative to their normoxia counterpart. In vitro functional test shows enhancement through chondrocyte proliferation, migration, and matrix deposition, while inhibit IL-1β-induced chondrocytes senescence, inflammation, matrix degradation, and pro-inflammatory macrophage activity. Multiple functional proteins, as well as a change in EVs' size profile, with enrichment of specific EV-miRNAs were detected with hypoxia preconditioning, implicating complex molecular pathways involved in hypoxia pre-conditioned MSCs secretome generated cartilage regeneration.

Nuclear protein-1 is the common link for pathways activated by aging and obesity in chondrocytes: A potential therapeutic target for osteoarthritis

Pathways leading to osteoarthritis (OA) are diverse depending on the risk factors involved; thus, developing OA therapeutics has been challenging. Here we report that nuclear protein-1 (Nupr1), a stress-inducible protein/transcription factor, is activated by pathways associated with obesity and aging in chondrocytes. Treatment of human chondrocytes with free fatty acids (palmitate and oleate; a model for high-fat diet/obesity) induced PERK signaling and increased expression of caspase-3, TRB3, and Nupr1. On the other hand, treatment of chondrocytes with menadione (oxidative stress inducer) induced oxidation of IRE1, activated antioxidant response (higher Nrf2 expression), and increased expression of Nupr1 and matrix metalloproteinases. Experimental OA was induced by destabilization of the medial meniscus (DMM) in the knee joints of Nupr1+/+ and Nupr1-/- mice. Loss of Nupr1 expression reduced the severity of cartilage lesions in this model. Together, our findings suggest that Nupr1 is a common factor activated by signaling pathways activated by obesity (ER stress) and age (oxidative stress) and a potential drug target for OA resulting from various risk factors.

"It's like a nail being driven in the ankle": A qualitative study of individuals' lived experiences to inform a core domain set for ankle osteoarthritis

OBJECTIVES

Explore individuals' lived experience with ankle osteoarthritis and to identify health-related domains for ankle osteoarthritis based on the perspectives of people living with the condition, as an initial step to address the International Foot and Ankle Osteoarthritis Consortium's recommendation to develop a core domain set for ankle osteoarthritis.

METHODS

A qualitative study using semi-structured interviews was conducted. Interviews were undertaken with individuals with symptomatic ankle osteoarthritis who were aged ≥35 years. Interviews were recorded, transcribed verbatim and thematically analysed.

RESULTS

Twenty-three individuals (16 females; mean (range) age 62 (42-80) years) were interviewed. Five themes were identified: pain, often severe, is a central feature of living with ankle osteoarthritis; stiffness and swelling are key symptoms; ankle osteoarthritis induced mobility impairments compromise enjoyment in life; ankle osteoarthritis instability and balance impairments lead to concerns about falling; there are financial implications of living with ankle osteoarthritis. We propose 17 domains based on individuals' experiences.

CONCLUSION

Study findings indicate that individuals with ankle osteoarthritis live with chronic ankle pain, stiffness and swelling which affect their ability to participate in physical, and social activities, maintain an active lifestyle, and work in physical occupations. From the data, we propose 17 domains that are important to people with ankle osteoarthritis. These domains require further evaluation to ascertain their inclusion in a core domain set for ankle osteoarthritis.

Therapeutic Modulation of Cell Morphology and Phenotype of Diseased Human Cells towards a Healthier Cell State Using Lignin

Despite lignin's global abundance and its use in biomedical studies, our understanding of how lignin regulates disease through modulation of cell morphology and associated phenotype of human cells is unknown. We combined an automated high-throughput image cell segmentation technique for quantitatively measuring a panel of cell shape descriptors, droplet digital Polymerase Chain Reaction for absolute quantification of gene expression and multivariate data analyses to determine whether lignin could therapeutically modulate the cell morphology and phenotype of inflamed, degenerating diseased human cells (osteoarthritic (OA) chondrocytes) towards a healthier cell morphology and phenotype. Lignin dose-dependently modified all aspects of cell morphology and ameliorated the diseased shape of OA chondrocytes by inducing a less fibroblastic healthier cell shape, which correlated with the downregulation of collagen 1A2 (COL1A2, a major fibrosis-inducing gene), upregulation of collagen 2A1 (COL2A1, a healthy extracellular matrix-inducing gene) and downregulation of interleukin-6 (IL-6, a chronic inflammatory cytokine). This is the first study to show that lignin can therapeutically target cell morphology and change a diseased cells' function towards a healthier cell shape and phenotype. This opens up novel opportunities for exploiting lignin in modulation of disease, tissue degeneration, fibrosis, inflammation and regenerative medical implants for therapeutically targeting cell function and outcome.

Post-traumatic osteoarthritis: the worst associated injuries and differences in patients' profile when compared with primary osteoarthritis

BACKGROUND

The estimated prevalence of post-traumatic osteoarthritis (PTOA) is 10-12% and in this study 12.4%. Different knee and hip injuries have been identified as risk factors for PTOA, but there is no consensus regarding the most painful and disabling injuries. Identifying these injuries might help in the prevention of PTOA. Additionally, patients with PTOA have a higher risk for complications after arthroplasty than patients with primary OA, perhaps due to differences in the profile and comorbidity that might help to explain the difference. This work aims 1) to identify the most common past injuries associated with the most painful and disabling PTOA cases in non-athlete patients and 2) to compare the comorbidities and characteristics between PTOA and primary OA.

METHODS

Retrospective hospital-based cohort study with 1290 participants with joint complaints or who received arthroplasty. Medical records included demographic information, diagnosis, medication, smoking, alcohol history and comorbidities. Data from January 2012 orthopaedic consults till December 2019 was reviewed and had the type and date of injury, pain score by the numerical rating scale and walking disability. Odds Ratio (OR) and 95% confidence intervals are presented.

RESULTS

There were 641 cases with primary OA (65% females) and 104 with PTOA (61% males). Patients with PTOA were 7.5 years younger (P < 0.001), reported more alcohol consumption (P = 0.01) and had higher odds of osteoporotic fractures (OP) and psychosis than patients with primary OA (OR = 2.0, CI = 1.06-3.78 and OR = 2.90, CI = -0.91-9.18, respectively). Knee fractures were most common in males and hip fractures in females (31% and 37.5%, respectively, P < 0.005). The PTOA-associated injuries with the highest pain and disability scores were meniscal injuries and hip fractures. Besides, in the group with primary OA, there were more diabetes, hypertension and hypothyroidism cases than in PTOA. However, after adjustment, differences were only significant for diabetes (OR_adj = 1.78, CI = 1.0-3.2).

CONCLUSIONS

Past meniscal injuries and hip fractures were the most relevant PTOA-associated injuries regarding pain and walking disability. This, together with differences in their profile when compared with primary OA, might help to decide the orthopaedic management of these injuries to prevent complications such as PTOA and recurrence, with appropriate preoperative planning, surgery choice and comorbidity treatment.

Dual-tissue transplantation versus osteochondral autograft transplantation in the treatment of osteochondral defects: a porcine model study

BACKGROUND

Osteochondral injury is a common sports injury, and hyaline cartilage does not regenerate spontaneously when injured. However, there is currently no gold standard for treating osteochondral defects. Osteochondral autograft transplantation (OAT) is widely used in clinical practice and is best used to treat small osteochondral lesions in the knee that are < 2 cm² in size. Autologous dual-tissue transplantation (ADTT) is a promising method with wider indications for osteochondral injuries; however, ADTT has not been evaluated in many studies. This study aimed to compare the radiographic and histological results of ADTT and OAT for treating osteochondral defects in a porcine model.

METHODS

Osteochondral defects were made in the bilateral medial condyles of the knees of 12 Dian-nan small-ear pigs. The 24 knees were divided into the ADTT group (n = 8), OAT group (n = 8), and empty control group (n = 8). At 2 and 4 months postoperatively, the knees underwent gross evaluation based on the International Cartilage Repair Society (ICRS) score, radiographic assessment based on CT findings and the magnetic resonance observation of cartilage repair tissue (MOCART) score, and histological evaluation based on the O'Driscoll histological score of the repair tissue.

RESULTS

At 2 months postoperatively, the ICRS score, CT evaluation, MOCART score, and O'Driscoll histological score were significantly better in the OAT group than the ADTT group (all P < 0.05). At 4 months postoperatively, the ICRS score, CT evaluation, MOCART score, and O'Driscoll histological score tended to be better in the OAT group than the ADTT group, but these differences did not reach statistical significance (all P > 0.05).

CONCLUSIONS

In a porcine model, ADTT and OAT are both effective treatments for osteochondral defects in weight bearing areas. ADTT may be useful as an alternative procedure to OAT for treating osteochondral defects.

Development and characterization of an intra-articular fracture mediated model of post-traumatic osteoarthritis

PURPOSE

This study aimed to develop and characterize a closed intra-articular fracture (IAF) mediated post-traumatic osteoarthritis (PTOA) model in rats to serve as a testbed for putative disease modifying interventions.

METHODS

Male rats were subject to a 0 Joule (J), 1 J, 3 J, or 5 J blunt-force impact to the lateral aspect of the knee and allowed to heal for 14 and 56 days. Micro-CT was performed at time of injury and at the specified endpoints to assess bone morphometry and bone mineral density measurements. Cytokines and osteochondral degradation markers were assayed from serum and synovial fluid via immunoassays. Histopathological analyses were performed on decalcified tissues and assessed for evidence of osteochondral degradation.

RESULTS

High-energy (5 J) blunt impacts consistently induced IAF to the proximal tibia, distal femur, or both while lower energy (1 J and 3 J) impacts did not. CCL2 was found to be elevated in the synovial fluid of rats with IAF at both 14- and 56-days post-injury while COMP and NTX-1 were upregulated chronically relative to sham controls. Histological analysis showed increased immune cell infiltration, increased osteoclasts and osteochondral degradation with IAF relative to sham.

CONCLUSION

Based on results from the current study, our data indicates that a 5 J blunt-forced impact adequately and consistently induces hallmark osteoarthritic changes to the articular surface and subchondral bone at 56 days after IAF. Marked development of PTOA pathobiology suggest this model will provide a robust testbed for screening putative disease modifying interventions that might be translated to the clinic for militarily relevant, high-energy joint injuries.

Decreased Synovial Fluid Ghrelin Level Is Associated With Acute Cartilage Injury in Patients With Anterior Cruciate Ligament Tear

Background

Ghrelin, an amino acid hormone secreted primarily from the stomach, can regulate bone metabolism, regulate inflammation via suppressing proinflammatory cytokines, and suppress expression of matrix metalloproteinases (MMPs).

Purpose

To measure synovial fluid levels of ghrelin in young patients with anterior cruciate ligament (ACL) tear to assess the role of ghrelin as a potential biomarker for cartilage injury.

Study Design

Controlled laboratory study.

Methods

This study included 120 patients who underwent ACL reconstructionbetween January 1, 2016, and May 31, 2021. We categorized 60 patients with acute cartilage injury (International Cartilage Regeneration & Joint Preservation Society grade 2 or 3) as the acute group and 60 patients with no acute cartilage injury as the nonacute group, with the healthy contralateral knee of each patient acting as the control group (n = 120). Synovial fluid samples were collected from the knees in the operating room before ACL reconstruction. We assessed the inflammatory biomarkers interleukin (IL)-6, MMP-1, MMP-9, and MMP-13, as well as serum ghrelin level and Mankin score, and results were compared between the 3 study groups with the Mann-Whitney U test.

Results

Lower serum ghrelin levels in the synovial fluid were found in the acute group compared with the nonacute group and healthy controls (232.4 vs 434.4 vs 421.5 pg/mL, respectively; P < .001). Ghrelin level in the synovial fluid was significantly and positively correlated with IL-6 (r = 0.4223; P < .0001), MMP-13 (r = 0.3402; P < .0001), and Mankin score (r = 0.1453; P = .0244).

Conclusion

In patients with ACL injury, ghrelin synovial fluid was significantly differently expressed in patients with cartilage injury and no cartilage injury.

Clinical Relevance

Ghrelin synovial fluid has the potential to be a biomarker to predict acute cartilage injury in patients with ACL injury.

Hippo Signaling Modulates the Inflammatory Response of Chondrocytes to Mechanical Compressive Loading

Knee osteoarthritis (KOA) is a degenerative disease resulting from mechanical overload, where direct physical impacts on chondrocytes play a crucial role in disease development by inducing inflammation and extracellular matrix degradation. However, the signaling cascades that sense these physical impacts and induce the pathogenic transcriptional programs of KOA remain to be defined, which hinders the identification of novel therapeutic approaches. Recent studies have implicated a crucial role of Hippo signaling in osteoarthritis. Since Hippo signaling senses mechanical cues, we aimed to determine its role in chondrocyte responses to mechanical overload. Here we show that mechanical loading induces the expression of inflammatory and matrix-degrading genes by activating the nuclear factor-kappaB (NFκB) pathway in a Hippo-dependent manner. Applying mechanical compressional force to 3-dimensional cultured chondrocytes activated NFκB and induced the expression of NFκB target genes for inflammation and matrix degradation (i.e., IL1β and ADAMTS4). Interestingly, deleting the Hippo pathway effector YAP or activating YAP by deleting core Hippo kinases LATS1/2 blocked the NFκB pathway activation induced by mechanical loading. Consistently, treatment with a LATS1/2 kinase inhibitor abolished the upregulation of IL1β and ADAMTS4 caused by mechanical loading. Mechanistically, mechanical loading activates Protein Kinase C (PKC), which activates NFκB p65 by phosphorylating its Serine 536. Furthermore, the mechano-activation of both PKC and NFκB p65 is blocked in LATS1/2 or YAP knockout cells, indicating that the Hippo pathway is required by this mechanoregulation. Additionally, the mechanical loading-induced phosphorylation of NFκB p65 at Ser536 is blocked by the LATS1/2 inhibitor Lats-In-1 or the PKC inhibitor AEB-071. Our study suggests that the interplay of the Hippo signaling and PKC controls NFκB-mediated inflammation and matrix degradation in response to mechanical loading. Chemical inhibitors targeting Hippo signaling or PKC can prevent the mechanoresponses of chondrocytes associated with inflammation and matrix degradation, providing a novel therapeutic strategy for KOA.

Improved Understanding of the Inflammatory Response in Synovial Fluid and Serum after Traumatic Knee Injury, Excluding Fractures of the Knee: A Systematic Review

BACKGROUND

Traumatic knee injury results in a 4- to 10-fold increased risk of post-traumatic osteoarthritis (PTOA). Currently, there are no successful interventions for preventing PTOA after knee injury. The aim of this study is to identify inflammatory proteins that are increased in serum and synovial fluid after acute knee injury, excluding intra-articular fractures.

METHODS

A literature search was done according to the PRISMA guidelines. Articles reporting about inflammatory proteins after knee injury, except fractures, up to December 8, 2021 were collected. Inclusion criteria were as follows: patients younger than 45 years, no radiographic signs of knee osteoarthritis at baseline, and inflammatory protein measurement within 1 year after trauma. Risk of bias was assessed of the included studies. The level of evidence was determined by the Strength of Recommendation Taxonomy.

RESULTS

Ten studies were included. All included studies used a healthy control group or the contralateral knee as healthy control. Strong evidence for interleukin 6 (IL-6) and limited evidence for CCL4 show elevated concentrations of these proteins in synovial fluid (SF) after acute knee injury; no upregulation in SF for IL-2, IL-10, CCL3, CCL5, CCL11, granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) was found. Limited evidence was found for no difference in serum concentration of IL-1β, IL-6, IL-10, CCL2, and tumor necrosis factor alpha (TNF-α) after knee injury.

CONCLUSION

Interleukin 6 and CCL4 are elevated in SF after acute knee injury. Included studies failed to demonstrate increased concentration of inflammatory proteins in SF samples taken 6 weeks after trauma. Future research should focus on SF inflammatory protein measurements taken less than 6 weeks after injury.

Correlation of Arthroscopic Grading and Optical Coherence Tomography as Markers of Early Repair and Predictors of Later Healing Evident on MRI and Histomorphometric Assessment of Cartilage Defects Implanted with Chondrocytes Overexpressing IGF-I

OBJECTIVE

Injury of articular cartilage is common, and due to the poor intrinsic capabilities of chondrocytes, it can precipitate joint degradation and osteoarthritis (OA). Implantation of autologous chondrocytes into cartilaginous defects has been used to bolster repair. Accurate assessment of the quality of repair tissue remains challenging. This study aimed to investigate the utility of noninvasive imaging modalities, including arthroscopic grading and optical coherence tomography (OCT) for assessment of early cartilage repair (8 weeks), and MRI to determine long-term healing (8 months).

DESIGN

Large (15 mm diameter), full-thickness chondral defects were created on both lateral trochlear ridges of the femur in 24 horses. Defects were implanted with autologous chondrocytes transduced with rAAV5-IGF-I, autologous chondrocytes transduced with rAAV5-GFP, naïve autologous chondrocytes, or autologous fibrin. Healing was evaluated at 8 weeks post-implantation using arthroscopy and OCT, and at 8 months post-implantation using MRI, gross pathology, and histopathology.

RESULTS

OCT and arthroscopic scoring of short-term repair tissue were significantly correlated. Arthroscopy was also correlated with later gross pathology and histopathology of repair tissue at 8 months post-implantation, while OCT was not correlated. MRI was not correlated with any other assessment variable.

CONCLUSIONS

This study indicated that arthroscopic inspection and manual probing to develop an early repair score may be a better predictor of long-term cartilage repair quality following autologous chondrocyte implantation. Furthermore, qualitative MRI may not provide additional discriminatory information when assessing mature repair tissue, at least in this equine model of cartilage repair.

Deep learning-based automatic pipeline for quantitative assessment of thigh muscle morphology and fatty infiltration

PURPOSE

Fast and accurate thigh muscle segmentation from MRI is important for quantitative assessment of thigh muscle morphology and composition. A novel deep learning (DL) based thigh muscle and surrounding tissues segmentation model was developed for fully automatic and reproducible cross-sectional area (CSA) and fat fraction (FF) quantification and tested in patients at 10 years after anterior cruciate ligament reconstructions.

METHODS

A DL model combining UNet and DenseNet was trained and tested using manually segmented thighs from 16 patients (32 legs). Segmentation accuracy was evaluated using Dice similarity coefficients (DSC) and average symmetric surface distance (ASSD). A UNet model was trained for comparison. These segmentations were used to obtain CSA and FF quantification. Reproducibility of CSA and FF quantification was tested with scan and rescan of six healthy subjects.

RESULTS

The proposed UNet and DenseNet had high agreement with manual segmentation (DSC >0.97, ASSD < 0.24) and improved performance compared with UNet. For hamstrings of the operated knee, the automated pipeline had largest absolute difference of 6.01% for CSA and 0.47% for FF as compared to manual segmentation. In reproducibility analysis, the average difference (absolute) in CSA quantification between scan and rescan was better for the automatic method as compared with manual segmentation (2.27% vs. 3.34%), whereas the average difference (absolute) in FF quantification were similar.

CONCLUSIONS

The proposed method exhibits excellent accuracy and reproducibility in CSA and FF quantification compared with manual segmentation and can be used in large-scale patient studies.

HWJMSC-derived extracellular vesicles ameliorate IL-1β-induced chondrocyte injury through regulation of the BMP2/RUNX2 axis via up-regulation TFRC

Articular osteochondral injury is a common and frequently occurring disease in orthopedics that is caused by aging, disease, and trauma. The cytokine interleukin-1β (IL-1β) is a crucial mediator of the inflammatory response, which exacerbates damage during chronic disease and acute tissue injury. Human Wharton's jelly mesenchymal stem cell (HWJMSC) extracellular vesicles (HWJMSC-EVs) have been shown to promote cartilage regeneration. The study aimed to investigate the influence and mechanisms of HWJMSC-EVs on the viability, apoptosis, and cell cycle of IL-1β-induced chondrocytes. HWJMSC-EVs were isolated by Ribo™ Exosome Isolation Reagent kit. Nanoparticle tracking analysis was used to determine the size and concentration of HWJMSC-EVs. We characterized HWJMSC-EVs by western blot and transmission electron microscope. The differentiation, viability, and protein level of chondrocytes were measured by Alcian blue staining, Cell Counting Kit-8, and western blot, respectively. Flow cytometer was used to determine apoptosis and cell cycle of chondrocytes. The results showed that HWJMSCs relieved IL-1β-induced chondrocyte injury by inhibiting apoptosis and elevating viability and cell cycle of chondrocyte, which was reversed with exosome inhibitor (GW4869). HWJMSC-EVs were successfully extracted and proven to be uptake by chondrocytes. HWJMSC-EVs ameliorate IL-1β-induced chondrocyte injury by inhibiting cell apoptosis and elevating viability and cycle of cell, but these effects were effectively reversed by knockdown of transferrin receptor (TFRC). Notably, using bone morphogenetic protein 2 (BMP2) pathway agonist and inhibitor suggested that HWJMSC-EVs ameliorate IL-1β-induced chondrocyte injury through activating the BMP2 pathway via up-regulation TFRC. Furthermore, over-expression of runt-related transcription factor 2 (RUNX2) reversed the effects of BMP2 pathway inhibitor promotion of IL-1β-induced chondrocyte injury. These results suggested that HWJMSC-EVs ameliorate IL-1β-induced chondrocyte injury by regulating the BMP2/RUNX2 axis via up-regulation TFRC. HWJMSC-EVs may play a new insight for early medical interventions in patients with articular osteochondral injury.

Combined unicompartmental knee arthroplasty and anterior cruciate ligament reconstruction in a young patient with post-traumatic arthritis

Post-traumatic arthritis can result in significant pain and difficulty in managing daily life activities. Multiple factors are weighed in selecting the proper surgical intervention, with patient age and level of activity being most important. Isolated osteoarthritis is a well-known indication for unicompartmental knee arthroplasty, where a better range of motion, preservation of natural knee kinematics and less invasive resection of knee joint bone are used. Moreover, the high improvement rate and long-term results after anterior cruciate ligament (ACL) reconstruction and restoration of knee stability can make the combined procedure favourable, particularly for young active patients.We report on an active man in his 30s presenting with isolated medial compartment advanced arthritis after sustaining distal femur intra-articular fracture. He was initially treated with partial unicompartmental knee replacement combined with ACL reconstruction, delivering a good short-term follow-up outcome.Though this case involves just a single patient, the positive outcome suggests that combined partial unicompartmental knee replacement with an ACL reconstruction should be considered for young and active patients diagnosed with isolated advanced medial compartment osteoarthritis.

Tramadol May Increase Risk of Hip Fracture in Older Adults with Post-Traumatic Osteoarthritis

Tramadol, an analgesic widely used for arthritic pain, is known to have adverse effects. This study investigated the association between the long-term use of tramadol for pain control and subsequent hip fractures in patients aged 60 years or older with posttraumatic osteoarthritis. This population-based retrospective cohort study included patients with posttraumatic osteoarthritis who received tramadol for pain control for more than 90 days within a 1-year period. A control cohort was enrolled using propensity score matching. The primary outcome was a new diagnosis of hip fracture requiring surgery. In total, 3093 patients were classified into each cohort. Tramadol use was identified as a risk factor for hip fracture (adjusted hazard ratio (aHR): 1.41; 95% confidence interval (CI): 1.09–1.82; p = 0.008), especially among patients aged 60–70 years (aHR: 2.11; 95% CI: 1.29–3.47; p = 0.003) and among male patients (aHR: 1.83; 95% CI: 1.24–2.70; p = 0.002). This is the first cohort study focusing on the association between long-term tramadol use and hip fracture among older adults with posttraumatic osteoarthritis. Tramadol, as a long-term pain control analgesic for older adults with posttraumatic osteoarthritis, may increase the risk of hip fracture, especially among male patients and those aged 60–70 years.

Application of Virtual Reality Systems in Bone Trauma Procedures

Background and Objectives: Bone fractures contribute significantly to the global disease and disability burden and are associated with a high and escalating incidence and tremendous economic consequences. The increasingly challenging climate of orthopaedic training and practice re-echoes the established potential of leveraging computer-based reality technologies to support patient-specific simulations for procedural teaching and surgical precision. Unfortunately, despite the recognised potential of virtual reality technologies in orthopaedic surgery, its adoption and integration, particularly in fracture procedures, have lagged behind other surgical specialities. We aimed to review the available virtual reality systems adapted for orthopaedic trauma procedures. Materials and Methods: We performed an extensive literature search in Medline (PubMed), Science Direct, SpringerLink, and Google Scholar and presented a narrative synthesis of the state of the art on virtual reality systems for bone trauma procedures. Results: We categorised existing simulation modalities into those for fracture fixation techniques, drilling procedures, and prosthetic design and implantation and described the important technical features, as well as their clinical validity and applications. Conclusions: Over the past decade, an increasing number of high- and low-fidelity virtual reality systems for bone trauma procedures have been introduced, demonstrating important benefits with regard to improving procedural teaching and learning, preoperative planning and rehearsal, intraoperative precision and efficiency, and postoperative outcomes. However, further technical developments in line with industry benchmarks and metrics are needed in addition to more standardised and rigorous clinical validation.

Reflections on Presurgical and Postsurgical Gait Mechanics After 50 Years of Total Ankle Arthroplasty and Perspectives on the Next Decade of Advancement

Although not the most prevalent form of lower limb pathology, ankle arthritis is one of the most painful and life-limiting forms of arthritis. Developing from overuse and various traumatic injuries, the effect of ankle arthritis on gait mechanics and effective treatment options for ankle arthritis remain an area of extensive inquiry. Although nonsurgical options are common (physical therapy, limited weight-bearing, and steroidal injections), surgical options are popular with patients. Fusion remains a common approach to stabilize the joint and relieve pain. However, starting in the early 1970s, total ankle arthroplasty was proposed as an alternative to fusion.

Dependence of crack shape in loaded articular cartilage on the collagenous structure

Cartilage cracks disrupt tissue mechanics, alter cell mechanobiology, and often trigger tissue degeneration. Yet, some tissue cracks heal spontaneously. A primary factor determining the fate of tissue cracks is the compression-induced mechanics, specifically whether a crack opens or closes when loaded. Crack deformation is thought to be affected by tissue structure, which can be probed by quantitative polarized light microscopy (PLM). It is unclear how the PLM measures are related to deformed crack morphology. Here, we investigated the relationship between PLM-derived cartilage structure and mechanical behavior of tissue cracks by testing if PLM-derived structural measures correlated with crack morphology in mechanically indented cartilages.

METHODS

Knee joint cartilages harvested from mature and immature animals were used for their distinct collagenous fibrous structure and composition. The cartilages were cut through thickness, indented over the cracked region, and processed histologically. Sample-specific birefringence was quantified as two-dimensional (2D) maps of azimuth and retardance, two measures related to local orientation and degree of alignment of the collagen fibers, respectively. The shape of mechanically indented tissue cracks, measured as depth-dependent crack opening, were compared with azimuth, retardance, or "PLM index," a new parameter derived by combining azimuth and retardance.

RESULTS

Of the three parameters, only the PLM index consistently correlated with the crack shape in immature and mature tissues.

CONCLUSION

In conclusion, we identified the relative roles of azimuth and retardance on the deformation of tissue cracks, with azimuth playing the dominant role. The applicability of the PLM index should be tested in future studies using naturally-occurring tissue cracks.

Hybrid-Total Ankle Arthroplasty (H-TAA) for Failed Talar Component in Mobile-Bearing Total Ankle Arthroplasty

INTRODUCTION

Revision Total Ankle Arthroplasty (TAA) surgery due to TAA aseptic loosening is increasing. It is possible to exchange the talar component and inlay to another system for isolated talar component loosening in a primary mobile-bearing TAA: Hybrid-Total Ankle Arthroplasty (H-TAA). The purpose of this study was to analyze the results of the revision surgery of an isolated aseptic talar component loosening in a mobile-bearing three-component TAA with a H-TAA solution.

METHODS

In this prospective case study, nine patients (six women, three men; mean age 59.8 years; range 41-80 years) with symptomatic isolated aseptic loosening of the talar component of a mobile-bearing TAA were treated with an isolated talar component and inlay substitution. In all nine cases, a hybrid TAA revision surgery was performed by implanting a VANTAGE TAA talar and insert component (Flatcut talar component: six cases, standard talar component: three cases). The patients were reviewed with the pain score (VAS Pain Score 0-10), Dorsiflexion/Plantarflexion (DF/PF) Range of Motion (ROM; degrees), the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle/Hindfoot Score (0-100 points), Sports Frequency Score (Level 0-4), and subjective Patients' Satisfaction Score (0-10 points).

RESULTS

The average Pain score improved significantly from preoperative 6.7 points to postoperative 1.1 points (p < 0.001). Average Dorsiflexion/Plantarflexion ROM values increased significantly post-surgery: 21.7° preoperative to 45.6° postoperative (p < 0.001). The postoperative AOFAS scores were significantly greater than the preoperative values: 47.7 points preoperative, 92.3 points postoperative (p < 0.001). The sports activity improved from preoperative to postoperative where, preoperative, none of the patients were able to perform sports. Postoperative, eight patients were able to be sports-active again. The overall average postoperative level of sports activity was 1.4. The postoperative average patient's satisfaction was 9.3 points.

CONCLUSIONS

In painful talar component aseptic loosening of a three-component mobile-bearing TAA, H-TAA is a good surgical solution for reducing pain, restoring ankle function, and improving patients' life quality.

Osteoarthritis: a narrative review of molecular approaches to disease management

Osteoarthritis (OA) is a chronic, progressive degenerative whole joint disease that affects the articular cartilage, subchondral bone, ligaments, capsule, and synovium. While it is still believed to be a mechanically driven disease, the role of underlying co-existing inflammatory processes and mediators in the onset of OA and its progression is now more appreciated. Post-traumatic osteoarthritis (PTOA) is a subtype of OA that occurs secondary to traumatic joint insults and is widely used in pre-clinical models to help understand OA in general. There is an urgent need to develop new treatments as the global burden is considerable and expanding. In this review, we focus on the recent pharmacological advances in the treatment of OA and summarize the most significant promising agents based on their molecular effects. Those are classified here into broad categories: anti-inflammatory, modulation of the activity of matrix metalloproteases, anabolic, and unconventional pleiotropic agents. We provide a comprehensive analysis of the pharmacological advances in each of these areas and highlight future insights and directions in the OA field.

Perception of Perioperative Risk for Arthroplasty Patients: A Poll of Indian Orthopedic Surgeons

BACKGROUND

A survey of the American Association of Hip and Knee Surgeons (AAHKS) reported that 95% of respondents attempted to modify risk factors prior to arthroplasty. This study investigated Indian arthroplasty surgeons' approach to patients who have modifiable risk factors.

METHODS

The AAHKS survey tool was adapted for Indian surgeons and distributed to the membership of the Indian Society of Hip and Knee Surgeons and Indian Arthroplasty Association via a Survey Monkey. A total of 92 survey responses were received, representing a response rate of 12%.

RESULTS

Overall, 87% of respondents restricted access to arthroplasty surgery for patients who have modifiable risk factors, but only 51% of respondents reported delays or restricted treatment because of risk factors. Respondents reported that financial implications were more likely to delay or restrict treatment in 97% and social/family reasons in 66%. Poor diabetic control (81%), previous infection (57%), and malnutrition/hypoalbuminemia (47%) were the most frequent modifiable risk factors. There were 82% of surgeons reporting that the patient's socioeconomic status influenced treatment including: 71% of patients who have low socioeconomic status, 57% who do not have insurance, and 45% who have limited social supports. Most surgeons (92%) reported that funding influenced the type of care provided and the choice of implants.

CONCLUSION

Over 97% of Indian arthroplasty surgeons thought socioeconomic factors impaired access to orthopaedic treatment. Only half the surgeons restricted access for comorbidities and these were more often related to infection risks and diabetes. These findings contrast dramatically to the practice patterns of American AAHKS members.

Complications, Implant Survivorships, and Functional Outcomes of Conversion Total Knee Arthroplasty With Prior Hardware

BACKGROUND

End-stage knee osteoarthritis with retained periarticular hardware is a frequent scenario. Conversion total knee arthroplasty (TKA) leads to excellent outcomes, but poses unique challenges. The evidence supporting retention versus removal of hardware during TKA is controversial.

METHODS

Patients who underwent TKA with prior hardware between January 2009 and December 2019 were identified. A total of 148 patients underwent TKA with prior hardware. The mean follow-up was 60 months (range, 24-223). Univariate and multivariable analyses were used to study correlations among factors and surgical-related complications, prosthesis failures, and functional outcomes.

RESULTS

The complication rate was 28 of 148 (18.9%). The use of a quadriceps snips in addition to a medial parapatellar arthrotomy was associated with a higher complication (odds ratio: 20.7, P < .05), implant failures (odds ratio: 13.9, P < .05), and lower the Veterans Rand 12 Mental Score (VR-12 MS) (-14.8, P < .05). Hardware removal versus retention and use of single versus multiple incisions were not associated with complications or prosthesis failures. Removal of all hardware was associated with significantly higher (+7.3, P < .05) VR-12 MS compared to retention of all hardware.

CONCLUSIONS

TKA with prior hardware was associated with more complications, implant failures, and lower VR-12 MS when a more constrained construct or quadriceps snip was performed. This probably reflects the level of difficulty of the procedure rather than the surgical approach used. Hardware removal or retention was not associated with complications or implant failures; however, removal rather than retention of all prior hardware is associated with increased general health outcomes.

LEVEL OF EVIDENCE

IV, cohort without control.

Metabolomic Phenotypes Reflect Patient Sex and Injury Status: A Cross-Sectional Analysis of Human Synovial Fluid

Background

Post-traumatic osteoarthritis (PTOA) is caused by knee injuries like anterior cruciate ligament (ACL) injuries. Often, ACL injuries are accompanied by damage to other tissues and structures within the knee including the meniscus. Both are known to cause PTOA but underlying cellular mechanisms driving disease remain unknown. Aside from injury, patient sex is a prevalent risk factor associated with PTOA.

Hypothesis

Metabolic phenotypes of synovial fluid that differ by knee injury pathology and participant sex will be distinct from each other.

Study Design

A cross-sectional study.

Methods

Synovial fluid from n=33 knee arthroscopy patients between 18 and 70 years with no prior knee injuries was obtained pre-procedure and injury pathology assigned post-procedure. Synovial fluid was extracted and analyzed via liquid chromatography mass spectrometry metabolomic profiling to examine differences in metabolism between injury pathologies and participant sex. Additionally, samples were pooled and underwent fragmentation to identify metabolites.

Results

Metabolite profiles revealed that injury pathology phenotypes were distinct from each other where differences in endogenous repair pathways that are triggered post-injury were detected. Specifically, acute differences in metabolism mapped to amino acid metabolism, lipid-related oxidative metabolism, and inflammatory-associated pathways. Lastly, sexual dimorphic metabolic phenotypes were examined between male and female participants, and within injury pathology. Specifically, Cervonyl Carnitine and other identified metabolites differed in concentration between sexes.

Conclusions

The results of this study suggest that different injuries (e.g., ligament vs. meniscus), as well as sex are associated with distinct metabolic phenotypes. Considering these phenotypic associations, a greater understanding of metabolic mechanisms associated with specific injuries and PTOA development may yield data regarding how endogenous repair pathways differ between injury types. Furthermore, ongoing metabolomic analysis of synovial fluid in injured male and female patients can be performed to monitor PTOA development and progression.

Clinical Relevance

Extension of this work may potentially lead to the identification of biomarkers as well as drug targets that slow, stop, or reverse PTOA progression based on injury type and patient sex.

A novel approach for joint line restoration in revision total ankle arthroplasty based on the three-dimensional registration of the contralateral tibia and fibula

PURPOSE

The use of total ankle arthroplasty (TAA) is increasing over time, as so will the need for revision TAAs in the future. Restoration of the ankle joint line (JL) in revision TAA is often difficult due to severe bone loss. This study analyzed the accuracy of a three-dimensional (3D) registration of the contralateral tibia and fibula to restore the ankle joint line (JL) and reported side-to-side differences of anatomical landmarks.

METHODS

3D triangular surface models of 96 paired lower legs underwent a surface registration algorithm for superimposition of the mirrored contralateral lower leg onto the original lower leg to approximate the original ankle JL using a proximal, middle and distal segment. Distances of the distal fibular tip, anterior and posterior medial colliculus to the JL were measured and absolute side-to-side differences reported. Anterior lateral distal tibial angle (ADTA) and lateral distal tibial angle (LDTA) were measured.

RESULTS

Mean JL approximation was most accurate for the distal segment (0.1 ± 1.4 mm (range: -3.4 to 2.8 mm)) and middle segment (0.1 ± 1.2 mm (range: -2.8 to 2.5 mm)) compared to the proximal segment (-0.2 ± 1.6 mm (range: -3.0 to 4.9 mm)) (p = 0.007). Distance of the distal fibular tip, the anterior, and posterior medial colliculus to the JL, ADTA and LDTA yielded no significant side-to-side differences (n.s.).

CONCLUSION

3D registration of the contralateral tibia and fibula reliably approximated the original ankle JL. The contralateral distal fibular tip, anterior and posterior medial colliculi, ADTA and LDTA can be used reliably for the planning of revision TAA with small side-to-side differences reported.

LEVEL OF EVIDENCE

IV.

Complications Following Total Ankle Arthroplasty Versus Ankle Arthrodesis for Primary Ankle Osteoarthritis

INTRODUCTION

There are minimal data comparing complications between ankle arthrodesis (AA) versus total ankle arthroplasty (TAR) for operative management of primary osteoarthritis (OA). This study aimed to compare outcomes following AA versus TAR for primary ankle OA using a large patient database.

METHODS

Patients who received AA or TAR for primary ankle OA from 2010 to 2019 were queried from PearlDiver. Rates of common joint complications were compared at 90 days, 1 year, and 2 years postoperatively using multivariable logistic regression.

RESULTS

A total of 1136 (67%) patients received AA and 584 (33%) patients underwent TAR. Patients that received AA exhibited significantly higher rates of at least one common joint complication at 90 days (19.3% vs 12.6%; odds ratio [OR] 1.69), 1 year (25.6% vs 15.0%; OR 2.00), and 2 years (26.9% vs 16.2%; OR 1.91) postoperatively. This included higher rates of adjacent fusion or osteotomy procedures, periprosthetic fractures, and hardware removal at each postoperative follow-up (all P < .05). Rates of prosthetic joint infection were comparable at 2 years postoperatively (4.3% vs 4.2%; OR 0.91).

CONCLUSION

The AA cohort exhibited higher rates of postoperative joint complications in the short and medium-term, namely, subsequent fusions or osteotomies, periprosthetic fractures, and hardware removal.

LEVELS OF EVIDENCE

Level III.

Reoperation Rates Following Total Ankle Arthroplasty Versus Ankle Arthrodesis for Posttraumatic Indications

AIMS

This studied aimed to compare rates of reoperation for patients who received primary ankle arthrodesis (AA) versus total ankle replacement (TAR) for posttraumatic indications between 2010 and 2016 Q2 using a nationwide claims database.

METHODS

A retrospective cohort study analyzing patients who received primary AA or TAR for posttraumatic indications was performed using PearlDiver. Reoperations assessed included prosthetic joint infection (PJI), hardware removal, adjacent joint fusion, and local open reduction internal fixation (ORIF). Multivariable logistic regression was used to compare rates of reoperations at 1 and 2 years postdischarge.

RESULTS

A total of 862 (74%) patients received AA and 318 (26%) patients underwent TAR for a posttraumatic indication. At 1 year, 305 (35.4%) AA patients had at least 1 reoperation compared with 55 (17.3%) TAR patients (OR 2.32; 95% CI, 1.68-3.26). At 2 years, 364 (42.2%) AA patients and 66 (20.8%) TAR patients had at least 1 reoperation (OR 2.51; 95% CI, 1.84-3.45). ORIF, hardware removal, and adjacent joint fusions were more likely for AA patients at both time intervals (all Ps < .05).

CONCLUSION

Patients who received primary AA for posttraumatic indications exhibited higher rates of major reoperations in the short to medium term compared with patients who underwent TAR.

LEVELS OF EVIDENCE

Level III: Retrospective cohort study.

Prevalence of radiographic ankle osteoarthritis in different subgroups of patients referred for ankle radiography

BACKGROUND

Ankle osteoarthritis(OA) has detrimental effects on physical health and has a relatively early disease onset compared to OA in other joints. However, the prevalence of radiographic ankle OA in different subgroups of patients referred for ankle radiography remains unknown. Therefore, we aimed to determine the prevalence of radiographic talocrural, subtalar and talonavicular OA(Kellgren-Lawrence scale ≥2) in a population referred for ankle radiography. Moreover, we aimed to identify differences in prevalence between specific subgroups of patients i.e. Body Mass Index (BMI), sex, age and reason for referral.

METHODS

A cross-sectional study was conducted at a radiology department serving primary and secondary care. Patients completed a questionnaire before radiography. Features of radiographic ankle OA were assessed for subgroups of patients, including; BMI, sex, age and reason for referral (chronic vs (sub)acute complaints). To examine the difference in (features of) radiographic OA for subgroups, multinomial and logistic regression were used to calculate Odds Ratios (ORs), with adjustment for age, sex and BMI.

RESULTS

Data from 893 patients that visited the radiology department across 16 months in 2017 or 2018 were included for analysis. Prevalence of radiographic ankle OA was 9.2%, 0.4% and 7.0%, for the talocrural, subtalar and talonavicular joint, respectively. Obesity was associated with radiographic talonavicular OA (adjusted OR 2.16, 95%CI:1.09; 5.26). Radiographic talocrural and talonavicular OA were both positively associated with male sex [(adjusted OR 4.64, 95%CI:276; 7.81) and (adjusted OR 1.95, 95%CI:1.13; 3.35), respectively].

CONCLUSION

Radiographic ankle OA was more common in men and obese patients that were referred to radiology.

Comparison of survival rates between total knee arthroplasty after a previous anterior cruciate ligament reconstruction and primary total knee arthroplasty via propensity score matching

INTRODUCTION

Although the survival rate of total knee arthroplasty (TKA) in patients treated with anterior cruciate ligament reconstruction (ACLR) is not as favorable as that in patients treated with primary TKA without ligament reconstruction, the exact survival rates and complications associated with these procedures are still controversial. Therefore, the purpose of the current study was to compare the revision rates of TKA in patients with knee osteoarthritis (OA) with a previous ACLR and those of patients with primary TKA with no history of knee surgery by using propensity score matching analysis.

MATERIALS AND METHODS

A list of patients who underwent TKA from January 1, 2008 to May 31, 2019 was obtained from the Korean National Health Insurance database. Among these, 460 patients underwent TKA in a knee with a previous ACLR and 569,766 patients who underwent primary TKA due to degenerative OA. We performed propensity scoring matching to compare the revision rates including septic revision due to prosthetic joint infection after TKA and perioperative complication rates within 90 days after revision TKA between the two groups.

RESULTS

Matched patients were assigned to one of the two groups (group A: 2,201 patients who underwent TKA due to primary OA, group B: 448 patients who underwent TKA in a knee with a previous ACLR) based on the propensity score. The total number of revisions per 1000 person-years was significantly higher in group B than in group A (10.16 vs 4.66, respectively). Group B showed a higher risk of revision than group A at 10 years post-TKA (hazard ratio: 2.49, 95% confidence interval: 1.30-4.77). However, group B showed a similar risk of septic revision as group A (p = 0.44). Perioperative complications within 90 days after TKA showed no significant differences between the groups.

CONCLUSIONS

Surgeons should be aware of the relatively higher revision rate of TKA in patients who had previously undergone an ACLR compared to that in patients who underwent primary TKA.

The epigenetic players and the chromatin marks involved in the articular cartilage during osteoarthritis

Epigenetics defines the modifications of the genome that do not involve a change in the nucleotide sequence of DNA. These modifications constitute a mechanism of gene regulation poorly explored in the context of cartilage physiology. They are now intensively studied by the scientific community working on articular cartilage and its related pathology such as osteoarthritis. Indeed, epigenetic regulations can control the expression of crucial gene in the chondrocytes, the only resident cells of cartilage. Some epigenetic changes are considered as a possible cause of the abnormal gene expression and the subsequent alteration of the chondrocyte phenotype (hypertrophy, proliferation, senescence…) as observed in osteoarthritic cartilage. Osteoarthritis is a joint pathology, which results in impaired extracellular matrix homeostasis and leads ultimately to the progressive destruction of cartilage. To date, there is no pharmacological treatment and the exact causes have yet to be defined. Given that the epigenetic modifying enzymes can be controlled by pharmacological inhibitors, it is thus crucial to describe the epigenetic marks that enable the normal expression of extracellular matrix encoding genes, and those associated with the abnormal gene expression such as degradative enzyme or inflammatory cytokines encoding genes. In this review, only the DNA methylation and histone modifications will be detailed with regard to normal and osteoarthritic cartilage. Although frequently referred as epigenetic mechanisms, the regulatory mechanisms involving microRNAs will not be discussed. Altogether, this review will show how this nascent field influences our understanding of the pathogenesis of OA in terms of diagnosis and how controlling the epigenetic marks can help defining epigenetic therapies.

Sport culture and communication among middle school athletes, parents, and staff: A qualitative study

Middle school (MS) is an intermediary level of education between elementary and secondary school that typically includes students aged 10-15 years. There is limited research within the MS sport setting, particularly related to sport-related injury prevention. This qualitative study aimed to better understand the sport culture within MS sports and the communication strategies used among invested groups (i.e., athletes, parents, staff inclusive of coaches and school nurses). Semi-structured interviews were conducted with 19 athletes, 20 parents, and 18 staff (e.g., coaches, school nurses) from seven MS in two school districts during the 2018/19 and 2019/20 school years. Topics focused on understanding school- and sport-related factors related to education, safety, and communication. Analysis used a consensual qualitative research tradition, in which the research team discussed individually developed themes and categories from transcribed interviews, with the goal of coming to a consensus and creating a codebook. Throughout the coding process, the research team would reconvene to discuss coding decisions until consensus was reached. This study focuses on the themes of sport culture and communication. Dominant categories identified within sport culture related to participants noting why they were interested in MS sports, and their struggles with their perceived roles and engagement (e.g., helping parents stay engaged, finding coaches, oversight of school nurses). Competitiveness and safety could have conflicting roles and priority. Dominant categories identified within communication centered around limited communication between coaches and parents. Technological assistance (e.g., phone apps, websites) was available, but often varied by school and sport. Concussions were seldom discussed unless during the preseason meeting or when one occurred. Findings highlight that the MS sport settings may struggle with incorporating primary prevention into their cultures and ensuring reliable communication among individuals. Novel and tailored approaches to injury prevention are needed to help ensure buy-in and proper implementation.

Protein-engineered biomaterials for cartilage therapeutics and repair

Cartilage degeneration and injury are major causes of pain and disability that effect millions, and yet treatment options for conditions like osteoarthritis (OA) continue to be mainly palliative or involve complete replacement of injured joints. Several biomaterial strategies have been explored to address cartilage repair either by the delivery of therapeutics or as support for tissue repair, however the complex structure of cartilage tissue, its mechanical needs, and lack of regenerative capacity have hindered this goal. Recent advances in synthetic biology have opened new possibilities for engineered proteins to address these unique needs. Engineered protein and peptide-based materials benefit from inherent biocompatibility and nearly unlimited tunability as they utilize the body's natural building blocks to fabricate a variety of supramolecular structures. The pathophysiology and needs of OA cartilage are presented here, along with an overview of the current state of the art and next steps for protein-engineered repair strategies for cartilage.

Sustained inhibition of CC-chemokine receptor-2 via intraarticular deposition of polymeric microplates in post-traumatic osteoarthritis

Posttraumatic osteoarthritis (PTOA) is mostly treated via corticosteroid administration, and total joint arthroplasty continues to be the sole effective intervention in severe conditions. To assess the therapeutic potential of CCR2 targeting in PTOA, we used biodegradable microplates (µPLs) to achieve a slow and sustained intraarticular release of the CCR2 inhibitor RS504393 into injured knees and followed joint damage during disease progression. RS504393-loaded µPLs (RS-µPLs) were fabricated via a template-replica molding technique. A mixture of poly(lactic-co-glycolic acid) (PLGA) and RS504393 was deposited into 20 × 10 μm (length × height) wells in a polyvinyl alcohol (PVA) square-patterned template. After physicochemical and toxicological characterizations, the RS504393 release profile from µPL was assessed in PBS buffer. C57BL/6 J male mice were subjected to destabilization of the medial meniscus (DMM)/sham surgery, and RS-µPLs (1 mg/kg) were administered intraarticularly 1 week postsurgery. Administrations were repeated at 4 and 7 weeks post-DMM. Drug free-µPLs (DF-µPLs) and saline injections were performed as controls. Mice were euthanized at 4 and 10 weeks post-DMM, corresponding to the early and severe PTOA stages, respectively. Knees were evaluated for cartilage structure score (ACS, H&E), matrix loss (safranin O score), osteophyte formation and maturation from cartilage to bone (cartilage quantification), and subchondral plate thickness. The RS-µPL architecture ensured the sustained release of CCR2 inhibitors over several weeks, with ~ 20% of RS504393 still available at 21 days. This prolonged release improved cartilage structure and reduced bone damage and synovial hyperplasia at both PTOA stages. Extracellular matrix loss was also attenuated, although with less efficacy. The results indicate that local sustained delivery is needed to optimize CCR2-targeted therapies.

The Short-Term Efficacy of Large-Focused and Controlled-Unfocused (Radial) Extracorporeal Shock Wave Therapies in the Treatment of Hip Osteoarthritis

Although the classical treatments listed in the guidelines for osteoarthritis are widely used, the majority of patients do not fully recover from their pain. It is a fact that new treatment methods are needed both to relieve pain and restore deteriorated joint function. No study has been found to date that evaluated the efficacy of ESWT in hip OA. This pilot trial is the first in the literature to investigate the comparative effects of the two ESWT types (f-ESWT and r-ESWT) in the treatment of hip OA. Briefly, 148 patients were randomly distributed into the three ESWT groups: focused (f-ESWT), radial (r-ESWT), and sham (s-ESWT). Patients were assessed with the Visual Analog Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores just before the treatment (0 week), just after the treatment (4th week), and 1 month after completion of the treatment (8th week). VAS and all WOMAC scores were significantly reduced at follow-up points (4th and 8th weeks) in both the f-ESWT and r-ESWT groups compared with baseline (0 week) (for all, p < 0.001). Statistical comparisons between the f-ESWT and r-ESWT groups showed that f-ESWT was superior to r-ESWT for the decrease in VAS and WOMAC scores from baseline to the 4th and 8th weeks (p < 0.001 or p < 0.002). Both r-ESWT and f-ESWT were found to have significant treatment efficacy compared with s-ESWT. However, f-ESWT produced a superior improvement in follow-up parameters compared to r-ESWT.

Mouse model of subtalar post-traumatic osteoarthritis caused by subtalar joint instability

BACKGROUND

Common ankle sprains are often accompanied by injury to the subtalar joint, which eventually leads to subtalar joint instability. Because the clinical manifestations for subtalar joint instability are similar to ankle joint injuries, these are often overlooked. This study aimed to establish an animal model of subtalar joint instability to study post-traumatic osteoarthritis of the subtalar joint caused by long-term subtalar joint instability and to provide a reference for future clinical research on chronic subtalar joint instability.

METHODS

In all, 24 C57BL/6 male mice were randomly divided into three groups: Sham, cervical ligament (CL) transection and CL + calcaneofibular ligament (CFL) transection groups. One week after surgical operation, all mice were trained to run in the mouse rotation fatigue machine every day. During this period, a balance beam test was used to evaluate the motor level and coordination ability of the mice before the operation and three days, one week, four weeks, eight weeks, and twelve weeks after operation. Further, post-traumatic osteoarthritis of the subtalar joint was quantified via micro-CT and histological staining.

RESULTS

The mice in the partial ligament transection group took significantly longer than those in the Sham group to pass through the balance beam and showed an increased number of hindfoot slips. Micro-CT analysis showed that the subtalar bone volume fraction in the CL + CFL transection group and CL transection group was 5.8% and 2.8% higher than that in the Sham group, respectively. Histological staining showed obvious signs of post-traumatic osteoarthritis (PTOA) in the subtalar joint of the ligament transection group.

CONCLUSIONS

The transection of CL and CL + CFL can cause instability of the subtalar joint in mice, resulting in a decrease in motor coordination, and long-term instability of the subtalar joint in mice can cause PTOA of the subtalar joint, which is manifested as destruction and loss of articular cartilage.

Total knee arthroplasty in post-traumatic osteoarthritis is more challenging, but results in similar patient satisfaction - An analysis of 1646 cases

BACKGROUND

Patients with post-traumatic osteoarthritis (PTOA) present a variety of technical challenges to surgeons. Surgical parameters, complication rates and patient-reported outcomes (PROs) have been reported as detrimental in total knee arthroplasty (TKA) for PTOA. The purpose of this study was to compare these variables and satisfaction with the results of TKA in patients with post-traumatic osteoarthritis with a matched-pair cohort of primary osteoarthritis (POA).

METHODS

A registry-embedded prospective case-control study was performed. Of a total of 1646 TKAs, 155 were performed due to PTOA between 2012 and 2019. One-hundred and thirty-six could be one-to-one propensity score-matched to patients with POA undergoing primary TKA based on similar patient demographic variables. Outcomes investigated included operation time, estimated blood loss, types of implants, postoperative complications and PROs pre- and 1 year postoperatively as well as satisfaction with the results of surgery. Sub-cohort analysis was performed for patients with prior fracture and soft tissue trauma, respectively.

RESULTS

Surgical parameters were significantly different in disadvantages of PTOA: operation time (P < 0.001), estimated blood loss (P < 0.001), blood transfusions (P = 0.039), type of implants (P < 0.001). Manipulation under anaesthesia (MUA) was necessary more often in the PTOA fracture group (odds ratio 5.01, (95% confidence interval 1.04; 24.07). PRO demonstrated no substantial differences after 1 year. Satisfaction with the results of TKA was as equally high in all cohorts.

CONCLUSIONS

This study demonstrated that TKAs in patients with PTOA require higher surgical effort but can result in similar PROs and satisfaction compared to POA, regardless of the underlying trauma.

Activating EGFR Signaling Attenuates Osteoarthritis Development Following Loading Injury in Mice

Posttraumatic osteoarthritis (PTOA) results in joint pain, loss of joint function, and impaired quality of daily life in patients with limited treatment options. We previously demonstrated that epidermal growth factor receptor (EGFR) signaling is essential for maintaining chondroprogenitors during articular cartilage development and homeostasis. Here, we used a nonsurgical, loading-induced PTOA mouse model to investigate the protective action of EGFR signaling. A single bout of cyclic tibial loading at a peak force of 6 N injured cartilage at the posterior aspect of lateral femoral condyle. Similar loading at a peak force of 9 N ruptured the anterior cruciate ligament, causing additional cartilage damage at the medial compartment and ectopic cartilage formation in meniscus and synovium. Constitutively overexpression of an EGFR ligand, heparin binding EGF-like growth factor (HBEGF), in chondrocytes significantly reduced cartilage injury length, synovitis, and pain after 6 N loading and mitigated medial side cartilage damage and ectopic cartilage formation after 9 N loading. Mechanistically, overactivation of EGFR signaling protected chondrocytes from loading-induced apoptosis and loss of proliferative ability and lubricant synthesis. Overexpressing HBEGF in adult cartilage starting right before 6 N loading had similar beneficial effects. In contrast, inactivating EGFR in adult cartilage led to accelerated PTOA progression with elevated cartilage Mankin score and synovitis score and increased ectopic cartilage formation. As a therapeutic approach, we constructed a nanoparticle conjugated with the EGFR ligand TGFα. Intra-articular injections of this nanoconstruct once every 3 weeks for 12 weeks partially mitigated PTOA symptoms in cartilage and synovium after 6 N loading. Our findings demonstrate the anabolic actions of EGFR signaling in maintaining articular cartilage during PTOA development and shed light on developing a novel nanomedicine for PTOA. © 2022 American Society for Bone and Mineral Research (ASBMR).

Study protocol for a randomised placebo controlled trial of platelet-rich plasma injection to prevent post-traumatic knee osteoarthritis after anterior cruciate ligament reconstruction

INTRODUCTION

The elevated cytokine levels in patients suffering from anterior cruciate ligament (ACL) rupture may lead to acute post-traumatic arthritis (APTA) and post-traumatic osteoarthritis (PTOA). Due to its chondrogenerative and anti-inflammatory effect, platelet-rich plasma (PRP) therapy is expected to show a positive outcome in APTA and PTOA. The proposed trial aims to quantitatively measure the efficacy of PRP injection in arresting post-traumatic cartilage degeneration among patients after ACL reconstruction.

METHODS AND ANALYSIS

This will be a single-blind, randomised, prospective, controlled clinical trial designed following the Consolidated Standards of Reporting Trials guidelines. After ACL reconstruction, 80 patients will be randomised to receive either leucocyte-poor PRP injection after joint aspiration or a placebo control group receiving only joint aspiration. Participants (age 20-49 years) will be those who have undergone ACL reconstruction within the past 2 weeks with a body mass index<35 and Kellgren Lawrence osteoarthritis grade<2. The primary outcome will include MRI-T2 values of knee cartilage at 6 months. The secondary outcomes will include pain assessment by Visual Analogue Scale, Knee injury and Osteoarthritis Outcome Score, blood and urine test, physical findings, measurements for muscle strength and joint stability.

ETHICS AND DISSEMINATION

The study was approved by The Independent Ethics Committee for Clinical Trials of the Japanese Association for the Promotion of State-of-the-Art Medicine. Results of the trial and each of the outcomes will be shared via conferences and publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

jRCTb030200391.

A review of Risk Factors for Post-traumatic hip and knee osteoarthritis following musculoskeletal injuries other than anterior cruciate ligament rupture

Post-traumatic osteoarthritis (PTOA) is a common form of osteoarthritis that might occur after any joint trauma. Most PTOA publications mainly focus on anterior cruciate ligament (ACL) injuries. However, many other traumatic injuries are associated with PTOA, not only for the knee but also for the hip joint. We aim to identify and summarize the existing literature on the musculoskeletal injuries associated with knee and hip PTOA and their risk factors in determining those with a worse prognosis, excluding ACL injuries. Despite the narrative nature of this review, a systematic search for published studies in the last twenty years regarding the most relevant injuries associated with a higher risk of PTOA and associated risk factors for OA was conducted. This review identified the six more relevant injuries associated with knee or hip PTOA. We describe the incidence, risk factors for the injury and risk factors for PTOA of each. Meniscal injury, proximal tibial fracture, patellar dislocation, acetabular, femoral fractures and hip dislocations are all discussed in this review.

Environmental Risk Factors for Osteoarthritis: The Impact on Individuals with Knee Joint Injury

Osteoarthritis is a debilitating chronic condition involving joint degeneration, impacting over 300 million people worldwide. This places a high social and economic burden on society. The knee is the most common joint impacted by osteoarthritis. A common cause of osteoarthritis is traumatic joint injury, specifically injury to the anterior cruciate ligament. The purpose of this review is to detail the non-modifiable and modifiable risk factors for osteoarthritis with particular focus on individuals after anterior cruciate ligament injury. After reading this, health care providers will better comprehend the wide variety of factors linked to osteoarthritis.

Greater Acute Articular Inflammatory Response in Tibial Plafond Fractures as Compared to Ankle Fractures

BACKGROUND

Several factors are thought to contribute to posttraumatic osteoarthritis (PTOA) development, including the posttraumatic inflammatory response. The purpose of this study was to compare 2 injuries at the same joint with a different severity and prognosis. This study compared the intra-articular inflammatory response after rotational ankle fracture (lower energy and less PTOA) with tibial plafond fracture (higher energy and more PTOA).

METHODS

This prospective comparative study was conducted at a level 1 trauma center between 2014-2019. Patients between 18 and 60 years of age with acute ankle or tibial plafond fractures were enrolled. Patients with preexisting ankle OA, autoimmune disease, additional injury, or open fractures were excluded. Synovial fluid aspirations were obtained within 24 hours of injury. The concentrations of interleukin (IL)-1β, IL-1 receptor antagonist (IL-1RA), IL-6, IL-8, and IL-10 and matrix metalloproteinase (MMP)-1, MMP-3, and MMP-13 were quantified.

RESULTS

Aspiration were obtained from 29 plafond fractures and 36 ankle fractures. Mean age was 43 years, and patients were predominately female (64%). Age, gender, and comorbidities did not vary between cohorts. Of the plafond fractures, 13 were 43-B and 16 were 43-C injuries. Ankle fractures were predominately 44-B injuries, and 15 ankle fracture had articular impaction. IL-10, IL-1β, IL-6, IL-8, MMP-1, MMP-3, and MMP-13 were all significantly higher in acute plafond fractures as compared to acute ankle fractures.

CONCLUSION

This study compared articular inflammatory marker profiles after fractures of different severities. Several cytokines were elevated in plafond fractures as compared to ankle fractures, suggesting a greater inflammatory response with plafond fractures. Given the difference in prognosis for and higher rate of PTOA after plafond fractures, these data strengthen the case that postinjury inflammatory response plays a role in PTOA development. Given that the postinjury inflammatory response is one of the few modifiable variables of these injuries, future research in this area remains important.

LEVEL OF EVIDENCE

Level II, prospective.

The talar body prosthesis treated end-stage ankle arthritis with talar body deficient: a 6-13 years of follow-up outcomes and 6-year survivorship

INTRODUCTION

Talar body deficient provides a unique challenge for ankle arthritis treatment. We studied the clinical-radiographic outcomes at 6 to 13 years and 6 year prosthesis survivorship of patients treated for ankle arthritis with poor talar body bone stock using a talar body prosthesis (TBP).

MATERIALS AND METHODS

Between 2008 and 2015, we treated 32 consecutive end-stage ankle arthritis patients with talar body deficiency by TBP implantation and fascia interposition. One patient was excluded with a diagnosis of inflammatory arthritis. We assessed visual analogue scale (VAS) of ankle pain, sagittal range of motion, American Orthopaedics Foot and Ankle Society (AOFAS) ankle-hindfoot score, Foot Ankle Ability Measure (FAAM) of activity daily living (ADL), prosthesis tibiotalar surface angle, radiographic prosthesis loosening, adjacent joint arthritis and complication. Pre-operative to last follow-up outcomes (at 6-13 years) were compared. Prosthesis survivorship was analyzed at 6 year follow-up. p < 0.05 was considered a significant difference.

RESULTS

There was statistically significant improvement of median VAS ankle pain, as 8.0 (IQR 1.0) to 1.0 (IQR 2.0), AOFAS ankle-hindfoot score from 48 (IQR 21) to 80 (IQR 7.0), FAAM of ADL from50.0 (28.0) to 88.0 (IQR 15.0), and sagittal ROM from 20^o (IQR 19°) to 33° (IQR 14°), p < 0.05. The median tibiotalar surface angle was statistically significant improved from 85.0° (IQR 8.0°) to 89.0° (IQR 3.0°), p < 0.001. No radiographic prosthesis loosening or adjacent talonavicular-calcaneocuboid joint arthritis. The 6 year prosthesis survivorship was 93.5% (95% CI 84.9-100.0%). End of survivorship was observed in 2 patients due to progressive valgus tilting at 16° and 18°, respectively. No prosthesis was revised.

CONCLUSIONS

TBP implantation with fascia replacing the articular end of distal tibia provided significant better pre- to post-operative clinical outcomes and had 6 year survivorship as 93.5% for the treatment of ankle arthritis with talar body deficient.

LEVEL OF EVIDENCE

IV.

Summary Report of the Arthritis Foundation and the American Orthopaedic Foot & Ankle Society's Symposium on Targets for Osteoarthritis Research: Part 1: Epidemiology, Pathophysiology, and Current Imaging Approaches

This first of a 2-part series of articles recounts the key points presented in a collaborative symposium sponsored jointly by the Arthritis Foundation and the American Orthopaedic Foot & Ankle Society with the intent to survey the state of scientific knowledge related to incidence, diagnosis, pathologic mechanisms, and injection treatment options for osteoarthritis (OA) of the foot and ankle. A meeting was held virtually on December 3, 2021. A group of experts were invited to present brief synopses of the current state of knowledge and research in this area. Part 1 overviews areas of epidemiology and pathophysiology, current approaches in imaging, diagnostic and therapeutic injections, and genetics. Opportunities for future research are discussed. The OA scientific community, including funding agencies, academia, industry, and regulatory agencies, must recognize the needs of patients that suffer from arthritis of foot and ankle. The foot and ankle contain a myriad of interrelated joints and tissues that together provide a critical functionality. When this functionality is compromised by OA, significant disability results, yet the foot and ankle are generally understudied by the research community. Level of Evidence: Level V - Review Article/Expert Opinion.

Radiological malunion after ankle fractures in older adults : definitions and new thresholds derived from clinical outcome data from the AIM trial

AIMS

The rationale for exacting restoration of skeletal anatomy after unstable ankle fracture is to improve outcomes by reducing complications from malunion; however, current definitions of malunion lack confirmatory clinical evidence.

METHODS

Radiological (absolute radiological measurements aided by computer software) and clinical (clinical interpretation of radiographs) definitions of malunion were compared within the Ankle Injury Management (AIM) trial cohort, including people aged ≥ 60 years with an unstable ankle fracture. Linear regressions were used to explore the relationship between radiological malunion (RM) at six months and changes in function at three years. Function was assessed with the Olerud-Molander Ankle Score (OMAS), with a minimal clinically important difference set as six points, as per the AIM trial. Piecewise linear models were used to investigate new radiological thresholds which better explain symptom impact on ankle function.

RESULTS

Previously described measures of RM and surgeon opinion of clinically significant malunion (CSM) were shown to be related but with important differences. CSM was more strongly related to outcome (-13.9 points on the OMAS; 95% confidence interval (CI) -21.9 to -5.4) than RM (-5.5 points; 95% CI -9.8 to -1.2). Existing malunion thresholds for talar tilt and tibiofibular clear space were shown to be slightly conservative; new thresholds which better explain function were identified (talar tilt > 2.4°; tibiofibular clear space > 6 mm). Based on this new definition the presence of RM had an impact on function, which was statistically significant, but the clinical significance was uncertain (-9.1 points; 95% CI -13.8 to -4.4). In subsequent analysis, RM of a posterior malleolar fracture was shown to have a statistically significant impact on OMAS change scores, but the clinical significance was uncertain (-11.6 points; 95% CI -21.9 to -0.6).

CONCLUSION

These results provide clinical evidence which supports the previously accepted definitions. Further research to investigate more conservative clinical thresholds for malunion is indicated.Cite this article: Bone Jt Open 2022;3(10):841-849.