Purpose:The aim of this systematic review and meta-analysis was twofold: (1) to synthesize magnetic resonance imaging (MRI)-based sagittal inclination angle (SIA) and coronal inclination angle (CIA) of the native anterior cruciate ligament (ACL) using standardized, tibial-axis-referenced measurements and (2) to compare inclination angles achieved by contemporary ACL reconstruction techniques relative to native ACL anatomy. Methods:A systematic search of MEDLINE, Embase and Cochrane CENTRAL was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The review was registered on Open Science Framework (OSF); registration number 10.17605/OSF.IO/K8HWRDEDXX. Studies reporting SIA and/or CIA of the native ACL or reconstructed ACL graft measured on MRI using tibial-axis-referenced techniques on true sagittal (for SIA) and true coronal (for CIA) imaging planes were included. Studies using alternative reference frames, oblique imaging, non-MRI modalities, cadaveric or animal models, double-bundle reconstruction or predominantly skeletally immature populations were excluded. Random-effects meta-analyses calculated pooled mean inclination angles with 95% confidence intervals (CIs). Results:Twenty-one studies comprising 2047 knees met the inclusion criteria. The pooled mean native ACL sagittal inclination angle was 50.4° (95% CI 49.0°-52.0°), whereas the pooled native coronal inclination angle was higher and more variable at 67.5° (95% CI 63.3°-71.8°). Anteromedial portal and outside-in techniques achieved sagittal and coronal graft orientations comparable to native ACL values. In contrast, transtibial reconstruction demonstrated significantly higher sagittal inclination angles. No significant differences in coronal inclination were observed across techniques. Conclusion:Sagittal graft orientation differs by technique, whereas coronal inclination shows substantial overlap, providing an anatomy-referenced framework for interpreting MRI-based graft alignment. Level of Evidence:Level IV, systematic review and meta-analysis of Level III and IV studies.

BACKGROUND:The zonal organization of articular cartilage is critical for the biphasic mechanical properties of the tissue. Current treatments for articular cartilage have yet to regenerate this zonal architecture, compromising the functional efficacy of the repaired tissue, which could account for tissue failure in the long term. Autologous chondrocyte implantation (ACI) still suffers from inconsistent efficacy and a long recovery period stemming from implantation of a heterogeneous chondrocyte mixture. HYPOTHESIS:Stratified implantation of zonal chondrocytes would facilitate the recapitulation of articular cartilage zonal properties and improve the repair efficacy of ACI treatment. STUDY DESIGN:Controlled laboratory study. METHODS:Autologous chondrocytes extracted from porcine articular cartilage were subjected to dynamic microcarrier expansion followed by size-based segregation using a spiral microfluidic device for the enrichment of zonal chondrocytes. Zonal chondrocytes were implanted into a chondral defect as a bilayered hydrogel construct consisting of superficial zone chondrocytes overlaying middle/deep zone chondrocytes (n = 6). Twelve months after implantation, the repair efficacy was compared against implantation of full-thickness cartilage-derived heterogeneous chondrocytes expanded on tissue culture plates (n = 5) or microcarriers (n = 6). RESULTS:Quantitative assessment of the repair tissues, including gross morphology, histological analysis, micro-computed tomography (micro-CT), compression modulus, and surface lubrication analysis, at 12 months demonstrated statistically significant improvement in cartilage and subchondral bone repair with zonal chondrocyte bilayered implantation. Magnetic resonance imaging (MRI) T2 mapping indicated progressive improvement in graft maturation as early as 3 months, reaching normalcy at 9 months. CONCLUSION:This study demonstrates that with appropriate expansion and isolation of zonal chondrocytes, stratified zonal chondrocyte implantation is able to facilitate restoration of articular cartilage zonal architecture and significantly enhance the functional repair as compared with current ACI treatment. CLINICAL RELEVANCE:With appropriate expansion and enrichment of zonal chondrocytes, stratified zonal chondrocyte implantation could represent a significant advancement over current ACI-based cartilage repair, with the potential to support quicker and better recovery.

BACKGROUND: Osteoarthritis (OA) is one of the most prevalent degenerative joint diseases, while the mechanism by which extracellular vesicles (EVs) promote chondrocyte regeneration remains unclear. The study assessed the effect of hypoxic mesenchymal stem cells (MSCs)-derived EVs on cartilage repair in a rat OA model. METHODS: The effects of EVs on chondrocyte regeneration and autophagy were evaluated in vitro. The influence of specific micro RNA (miRNA) and downstream target genes was examined following EV miRNA sequencing and multiple intersecting database analysis. RESULTS: We found EVs derived from hypoxia preconditioned human MSCs to promote cartilage repair in rat OA and enhance the proliferation and migration of chondrocytes in vitro, mediated via chondrocyte autophagy. MiRNA sequencing revealed a significant enrichment of miRNA122-5p in hypoxic MSCs EV, which through regulation of the target gene, DUSP2, mediated autophagy and participated in chondrocyte regeneration. DUSP2 regulation of chondrocyte autophagy could act via the phosphorylation of ERK1/2 and P38. CONCLUSIONS: This study demonstrates that EVs released by MSCs under hypoxic conditions have a beneficial effect on chondrocyte regeneration. A novel mechanism for chondrocyte autophagy is mediated by miR122-5P and DUSP2 target molecules, providing new insights into OA treatments.

Osteoarthritis (OA) is a prevalent degenerative joint disorder with significant socioeconomic impact. Despite advances in understanding its pathophysiology, current therapeutic strategies remain largely palliative. Small extracellular vesicles (sEV) have emerged as crucial mediators of intercellular communication in joint tissues, offering new insights into OA pathogenesis and potential therapeutic targets. This review explores the application of multi-omics approaches to sEV research in OA, assessing how these advanced technologies are contributing to our understanding of the disease and their potential to revolutionize OA management. We discuss the latest findings on the role of sEV in OA, the applications of multi-omics technologies in deciphering sEV cargo, the progress toward clinical translation, and the challenges and opportunities in this field. By synthesizing current knowledge and identifying key research gaps, this review provides a roadmap for leveraging sEV multi-omics to bridge the gap between molecular discoveries and clinical applications in OA.

PURPOSE:Rotational instability, post-operative high-grade pivot shifts and graft re-rupture are areas of debate in anterior cruciate ligament reconstruction (ACLR). Lateral extra-articular tenodesis (LET) techniques can control rotational laxity and reduce re-rupture by strengthening the anterolateral knee. Over-constraint and early-onset osteoarthritis are documented sequelae. This review compares the clinical, functional and patient-reported outcomes of ACLR with and without LET. METHODS:Studies on the comparative outcomes of ACLR with and without LET were identified. All clinical, functional and patient-reported outcomes were extracted. The quality of each study was assessed. Random-effects model was then used to obtain pooled estimates of procedural differences for each outcome if they were reported by three or more studies. RESULTS:Twenty-seven studies and 3225 patients were included. ACR with LET conferred statistically significant better laxity reduction through KT1000 testing with pooled RR estimate of 0.83 (95% confidence interval [CI], 0.73-0.95) and a better side-side comparison of anterior tibial translation with pooled WMD estimate of 0.61 (95% CI, 0.22-0.99). LET further lowered rates of graft failure/re-rupture with a pooled RR estimate of 0.93 (95% CI, 0.90-0.95). There was no significant difference in time taken for return to sports with a pooled WMD estimate of 0.00 (95% CI, -1.80 -1.80) or in subjective patient-reported outcome measures such as IKDC subjective score with a pooled WMD estimate of -0.75 (95% CI, -2.18 to 0.68), Lysholm score with a pooled WMD estimate of -1.73 (95% CI, -4.12 to 0.67), or Tegner activity index with a pooled WMD estimate of -0.55 (95% CI, -1.11 to 0.02). Osteoarthritic data was not assessed in this review due to the lack of data. CONCLUSION:LET addition confers better clinical outcomes over isolated ACLR. However, there is no significant difference between functional outcomes regarding returning to sports or subjective patient-reported outcome measures. LEVEL OF EVIDENCE:Level II.

Chronic low back pain, typically managed through lumbar fusion, demands innovative approaches to enhance therapeutic outcomes. This study investigated the efficacy of small extracellular vesicles (sEVs) derived from bone marrow mesenchymal stem cells (BMSCs) cultured in three-dimensional (3D) scaffolds concurrently under electromagnetic fields (EMF) stimulation, aiming to enhance osteogenesis and angiogenesis in a rat lumbar fusion model. We utilized a composite of polycaprolactone (PCL) and hydroxyapatite (HA), engineered via 3D printing, to create the scaffolds. sEVs were harvested from BMSCs under three distinct conditions: standard 2D cultures, 3D scaffolds, and 3D scaffolds with EMF stimulation. Specifically, the sEVs from the EMF-stimulated 3D cultures (3D/E-sEVs) were incorporated into these scaffolds before being implanted into rat spines. Therapeutic effectiveness was evaluated in vitro through assays for cell proliferation, migration, and angiogenesis, and in vivo via X-ray imaging, micro-computed tomography (micro-CT), and histological analyses. Results revealed that 3D/E-sEVs markedly enhanced both osteogenesis and angiogenesis. Further mechanistic investigations identified the PTEN/PI3K/AKT signalling pathway as essential in mediating these regenerative effects. Moreover, 3D PCL/HA scaffold loaded with 3D/E-sEVs promote lumbar fusion in a rat model. Conclusively, our findings demonstrated that 3D-printed PCL/HA scaffolds engineered with 3D/E-sEVs significantly promoted bone regeneration and vascular formation, thereby improving lumbar fusion outcomes. This study highlights the profound potential of integrating advanced tissue engineering techniques with cellular therapies to revolutionize the treatment of chronic low back pain and enhance surgical success rates.

Background: The anterior cruciate ligament (ACL) fails to heal after rupture, leading to joint instability and an increased risk of osteoarthritis. Mesenchymal stem/stromal cell (MSC) exosomes have reported wide-ranging therapeutic efficacy; however, their potential for augmenting ACL repair remains to be investigated.Purpose: To evaluate the use of MSC exosomes with fibrin sealant on biological augmentation of ACL healing after suture repair and their effects on ACL fibroblast functions.Study Design: Controlled laboratory study.Methods: Twelve rabbit knees underwent ACL transection and suture repair. MSC exosome and fibrin composite (Exosome+Fibrin) or fibrin (Fibrin) alone was used to supplement the suture repair in 6 knees. ACL repair was assessed by magnetic resonance imaging at 6 and 12 weeks postoperatively and by histologic and immunohistochemical analyses at 12 weeks. To investigate the mechanisms through which MSC exosomes augment ACL repair, metabolic activity, proliferation, migration, and matrix synthesis assays were performed using the primary ACL fibroblasts. RNA sequencing was also performed to assess global gene expression changes in exosome-treated ACL fibroblasts.Results: Based on magnetic resonance imaging findings, 5 of 6 Exosome+Fibrin-treated ACLs were completely or partially healed, as opposed to 5 of 6 Fibrin-treated ACLs appearing torn at 6 and 12 weeks postoperatively. Additionally, 4 of 6 Exosome+Fibrin-treated ACLs were isointense, as compared with 5 of 6 Fibrin-treated ACLs that were hyperintense, indicating improved remodeling and maturation of the repaired ACLs with Exosome+Fibrin treatment. Histologically, Exosome+Fibrin-treated ACLs showed more organized collagen fibers and abundant collagen deposition, with a high amount of collagen I and relatively lower amount of collagen III, which are consistent with the matrix structure and composition of the normal ACL. Cell culture studies using ACL fibroblasts showed that MSC exosomes enhanced proliferation, migration, and collagen synthesis and deposition, which are cellular processes relevant to ACL repair. Further gene set enrichment analysis revealed key pathways mediated by MSC exosomes in enhancing proliferation and migration while reducing matrix degradation of ACL fibroblasts.Conclusion: The combination of MSC exosomes and fibrin sealant (Exosome+Fibrin) applied to a suture repair enhanced the morphologic and histologic properties of the ACL in a rabbit model, and these improvements could be attributed to the augmented functions of ACL fibroblasts with exosome treatment.Clinical Relevance: This work supports the use of MSC exosomes in biological augmentation of ACL healing after suture repair.

Non-viral gene delivery holds significant promise for the treatment of various diseases. Solid lipid nanoparticles (SLNs) are emerging as promising gene delivery vehicles due to their ease of manufacture and high stability. However, the development of efficient and safe SLNs remains a challenge. This study aims to develop ionizable lipid-incorporated PEGylated SLNs (PEG-iSLNs) for effective mRNA and plasmid DNA (pDNA) delivery. Using a solvent emulsification/evaporation technique, a series of PEG-iSLNs were formulated at various weight ratios of the ionizable lipid ALC-0315 to the cationic lipid DOTMA. PEG-iSLNs formulated at an optimal ALC-0315/DOTMA ratio had superior mRNA transfection potency and membrane fusion activity over those with either ALC-0315 or DOTMA alone. iSLNs and PEG-iSLNs appeared to remain stable during storage at 4 °C over 18 and 12 months, respectively. Bioluminescence imaging study demonstrated the feasibility of the top-performing candidate, PEG-iSLN-3, for in vivo delivery of mRNA via both intramuscular and footpad subcutaneous routes, highlighting its potential as an efficient and nontoxic delivery vehicle for diverse nucleic acid cargoes.

The current study aims to evaluate the outcomes of the Bernese periacetabular osteotomy when performed for secondary hip dysplasia. In this retrospective case series, 20 patients with secondary hip dysplasia due to underlying neuromuscular conditions (ambulatory cerebral palsy) or skeletal dysplasias (multiple epiphyseal dysplasia, residual Perthes, hereditary multiple exostosis), who underwent the Bernese periacetabular osteotomy, were included. Statistically significant radiological and clinical improvements were noted for the acetabular angle, Tonnis angle, lateral central edge angle and Harris hip scores post-operatively over an average follow-up period of 5 years. Adjunctive procedures were required for patients with underlying neuromuscular conditions (proximal femur osteotomy) and hereditary multiple exostosis (surgical hip dislocation). The Bernese periacetabular osteotomy, together with adjunctive procedures, is a viable surgical option for patients with secondary hip dysplasia.

Abstract Background Predicting hamstring graft size preoperatively for anterior cruciate ligament (ACL) reconstruction is important for preempting an insufficient diameter in graft size intraoperatively, possibly leading to graft failure. While there are multiple published methods using magnetic resonance imaging (MRI) picture archiving and communication systems (PACS), most are not feasible and practical. Our study aims to (1) practically predict the ACL hamstring graft size in a numerically continuous manner using the preoperative MRI from any native MRI PACS system, (2) determine the degree of correlation between the predicted and actual graft size, and (3) determine the performance of our prediction method if we define an adequate actual graft size as ≥ 8 mm. Methods A retrospective review of 112 patients who underwent primary ACL reconstruction with quadrupled hamstring semitendinosus-gracilis grafts at a tertiary institution was conducted between January 2018 and December 2018. Graft diameter can be predicted in a numerically continuous manner as √[2*(AB + CD)], where A and B are the semitendinosus cross-sectional length and breath, respectively, and C and D are the gracilis cross-sectional length and breath, respectively. Results A moderately positive correlation exists between the predicted and actual graft diameter (r = 0.661 and p < .001). Our method yields a high specificity of 92.6% and a moderate sensitivity of 67.2% if we define an adequate actual graft size as ≥ 8 mm. An area under receiver-operating characteristic curve shows good discrimination (AUC = 0.856). Conclusions We present a practical method to predict the ACL hamstring graft size with high specificity using preoperative MRI measurements.

In recent years, silk fibroin (SF) has been incorporated with low crystallinity nanohydroxyapatite (nHA) as a scaffold for various tissue regeneration applications due to the mechanical strength of SF and osteoconductive properties of nHA. However, currently, there is a lack of understanding of the immune response toward the degradation products of SF with nHA composite after implantation. It is known that particulate fragments from the degradation of a biomaterial can trigger an immune response. As the scaffold is made of degradable materials, the degradation products may contribute to the inflammation. Therefore, in this study, the effects of the enzymatic degradation of the SF/nHA scaffold on macrophage response were investigated in comparison to the control SF scaffold. Since the degradation products of a scaffold can influence macrophage polarization, it can be hypothesized that as the SF and SF/nHA scaffolds were degraded in vitro using protease XIV solution, the degradation products can contribute to the polarization of THP-1-derived macrophages from pro-inflammatory M1 to anti-inflammatory M2 phenotype. The results demonstrated that the initial (day 1) degradation products of the SF/nHA scaffold elicited a pro-inflammatory response, while the latter (day 24) degradation products of the SF/nHA scaffold elicited an anti-inflammatory response. Moreover, the degradation products from the SF scaffold elicited a higher anti-inflammatory response due to the faster degradation of the SF scaffold and a higher amino acid concentration in the degradation solution. Hence, this paper can help elucidate the contributory effects of the degradation products of SF and SF/nHA scaffolds on macrophage response and provide greater insights into designing silk-based biomaterials with tunable degradation rates that can modulate macrophage response for future tissue regeneration applications.

PURPOSE:The J-sign is a clinical evaluation tool that assesses for patellar maltracking and is considered positive if lateral translation of the patella in extension, in the pattern of an inverted J is observed. This study aims to determine the association of clinical J-sign with imaging features noted on dynamic kinematic computed tomography (DKCT). METHODS:A retrospective review was conducted by reviewing the clinical records of all patients aged 18 years or younger who had a CT patellar tracking scan done between 1 January 2005 to 31 December 2016 in a single institution. Patients who had the presence or absence of a 'J-sign' evaluated clinically were included. Radiographic parameters evaluated using the axial cuts include the patellar tilt angle, congruence angle, Dejour's classification, femoral sulcus angle, trochlear groove depth, and Wiberg's classification. Patients were then divided into two groups based on the presence or absence of J-sign on clinical examination. The radiographic measurements were then analyzed for association with the presence or absence of J-sign on clinical examination. RESULTS:Patients with a positive J-sign had an increased patellar tilt of 23.3° ± 14.2° and an increased congruence angle of 47.1° ± 28.5° when measured in extension as compared to a patellar tilt of 18.3° ± 10.8° and a congruence angle of 32.1° ± 20.8° in patients with a negative J-sign (p = 0.024 and 0.004, respectively). Comparisons of the change in congruence angles with the knee in full extension and at 20° flexion also yielded significantly higher change of 28.0° ± 20.4° in patients with a positive J-sign as compared to 11.9° ± 17.5° in patients with a negative J-sign. Patients with a positive J-sign also had an increased TT-TG distance of 17.6 ± 5.6 mm as compared to a TT-TG distance of 14.7 ± 6.9 mm in patients with a negative J-sign (p = 0.01). CONCLUSION:Patients with a positive J-sign had an increased patellar tilt and an increased congruence angle when measured in extension. Increased TT-TG distance was also significantly associated with positive J-sign. Patients with a positive J-sign also had a greater change in their congruence angle when measured with the knee in full extension and at 20° of flexion.

The ideal surgical management for tibial eminence avulsion fractures remains controversial with varying approach, methods of fixation and post-operative regimes reported throughout literature. The current systematic review and meta-analysis aims to compare between the different approaches, methods of fixation and post-operative regimes for tibial eminence fractures. The systematic review was conducted according to PRISMA guidelines. A search was conducted using PubMed, MEDLINE and CINAHL databases. The keywords used were “anterior cruciate ligament”, “tibial spine” or “tibial eminence” and “fracture” or “avulsion”. All original human studies that reported the surgical outcomes of tibial eminence fractures were included. Individual patient data meta-analysis was performed. 48 studies with 1367 patients were included. Arthroscopic fixation resulted in significantly greater stability in terms of anterior drawer test (p = 0.018) and Lachman’s test (p = 0.042), as compared to open fixation, though there was no significant difference for pivot shift test. There was no significant difference identified in functional scores and activity, including Lysholm score, IKDC subjective score, Tegner score and return to sports. Suture fixation had significantly increased stability compared to screw fixation, in terms of anterior drawer test (p = 0.001) and Lachman’s test (p = 0.001), though no significant difference was identified for pivot shift test. Significantly better subjective scores and return to activity were also noted for suture fixation, in terms of Lysholm score (p = 0.008), IKDC subjective score (p = 0.001) and Tegner score (p = 0.001), though no significant difference was identified for return to sports. Arthroscopic and suture fixation had significantly superior outcomes when compared to open and screw fixation. Arthroscopic fixation resulted in significantly improved stability of the knee as compared to open fixation, though no significant difference was identified in terms of functional knee scores and return to activity. Suture fixation resulted in significantly improved stability of the knee and functional knee screws as compared to screw fixation.

Background: Literature is sparse on outcome comparisons between different trochleoplasty techniques in the treatment of patella instability. To date, it is unclear whether there is a technique that offers superior outcomes. This systematic review and meta-analysis aims to compare and evaluate the outcomes of trochleoplasty techniques in the treatment of patellofemoral instability in trochlea dysplasia to establish whether there is an ideal choice of trochleoplasty technique for superior outcomes. Methods: 21 studies involving 880 knees were included. The mean age of the patients was 21.7 years (range 8–49 years). Mean follow-up timeframe of 43.5 months (range 8.8–100 months). Clinical outcomes assessed included rates of recurrence of patellofemoral dislocation, patient satisfaction, Kujala score, International Knee Documentation Committee (IKDC) score, Tegner score, and Lysholm score. Egger’s test showed no publication bias across all outcomes assessed. Results: Favourable results were seen across all outcomes assessed and patient satisfaction. Improvements were seen with Kujala, IKDC, and Lysholm scores. Tegner scores showed good return to function. Post-operative dislocation and complication rates were low across the different techniques. Meta-regression for Kujala and IKDC scores showed good outcomes regardless of trochleoplasty technique used (Kujala, p = 0.549, relative risk 492.06; IKDC, p = 0.193, RR 0.001). The exact risk that trochleoplasty poses to the cartilage remains uncertain, as no study had a conservatively managed arm for comparison. Conclusions: Trochleoplasty yielded good outcomes irrespective of technique used with no clear superiority demonstrated in any technique in terms of outcome scores, satisfaction, post-operative dislocation rates or complications.

There are limited studies that have reported the middle- to long-term outcomes of combined procedures consisting of more than two procedures for patellofemoral instability. The current study aims to investigate and report the middle- to long-term outcomes of a combination procedure of tibial tubercle transfer, medial patellofemoral ligament reconstruction, trochleoplasty and lateral release for patellofemoral instability in patients aged 18 years and below. In the cohort study, all patients aged 18 years old or younger who underwent a combination procedure of tibial tubercle transfer, medial patellofemoral ligament reconstruction, trochleoplasty and lateral release for recurrent patellofemoral instability were included. A total of 21 patients were included in the study. All patients had no further patellofemoral dislocation, pain and apprehension following the 4-in-1 surgery (p < 0.01). There was a significant improvement in the Kujala score from 36.1 (SD 12.9) pre-operatively to 93.1 (SD 3.6) post-operatively (p < 0.001). The patients also had a statistically significant improvement in their radiological factors, including the patellar tilt angle (p < 0.001), sulcus angle (p = 0.001), trochlear groove depth (p = 0.041), tibial tubercle-trochlear groove distance (p < 0.001) and Caton–Deschamps index (p = 0.001). A combination procedure of tibial tubercle transfer, medial patellofemoral ligament reconstruction, trochleoplasty and lateral release leads to good middle- to long-term subjective, functional and radiographic outcomes for patients with recurrent patellofemoral instability and underlying predisposing factors of increased TT-TG distance of more than 20 mm, Dejour B or D trochlear dysplasia and medial patellofemoral ligament rupture. IV.

Osteoarthritis (OA) is a degenerative disease that significantly impairs quality of life. There is a pressing need for innovative OA therapies. While small extracellular vesicles (sEVs) show promising therapeutic effects against OA, their limited yield restricts clinical translation. Here, we devised a novel production system for sEVs that enhances both their yield and therapeutic properties. By stimulating mesenchymal stem cells (MSCs) using electromagnetic field (EMF) combined with ultrasmall superparamagnetic iron oxide (USPIO) particles, we procured an augmented yield of EMF-USPIO-sEVs. These vesicles not only activate anabolic pathways but also inhibit catabolic activities, and crucially, they promote M2 macrophage polarization, aiding cartilage regeneration. In an OA mouse model triggered by anterior cruciate ligament transection surgery, EMF-USPIO-sEVs reduced OA severity, and augmented matrix synthesis. Moreover, they decelerated OA progression through the microRNA-99b/MFG-E8/NF-κB signaling axis. Consequently, EMF-USPIO-sEVs present a potential therapeutic option for OA, acting by modulating matrix homeostasis and macrophage polarization.

PURPOSE:The objective of this study was to evaluate the Masada and Jo classifications for clinical use in patients with forearm deformity caused by hereditary multiple osteochondroma and propose a new classification system that is all-inclusive and can guide clinical management. METHODS:A retrospective review of 275 forearms was performed. A split-sample approach was used, where 138 forearms were analyzed to create a new classification, which was then validated on the remaining 137 forearms. Radiographs were reviewed to determine the number and location of osteochondromas and the presence of radial head dislocation (RHD) and to measure radiographic parameters. Multivariable logistic regression analysis was performed to identify radiological parameters associated with RHD. RESULTS:According to the Masada and Jo classifications, 95 of 275 forearms (34.5%) were unclassifiable. Analyses of the split group (n = 138) revealed 42 forearms with RHD. All these had distal ulna lesions, qualifying as the greatest associated factor for RHD. Further subgroup multivariable logistic regression analysis of forearms with distal ulna lesions identified radiological parameter proportional ulna length as a statistically significant association of RHD, qualifying as "at-risk" criteria. The area under the receiver operating characteristic curve for proportional ulna length was 0.89, with a receiver operating characteristic-derived ideal value of ≤ 0.95 (sensitivity 0.86 and specificity 0.86). CONCLUSIONS:We proposed a new classification system stratified into three groups-high, moderate, and low-risk of RHD-based on the identified factors associated with RHD. Type 1 comprises forearms with distal ulna osteochondromas-subdivided into type 1A (high-risk), where forearms meet the at-risk criteria for RHD and type 1B (moderate-risk), where forearms do not meet the at-risk criteria. Type 2 (low-risk) comprises forearms without distal ulna osteochondromas. CLINICAL RELEVANCE:Our classification system addresses the limitations of existing classifications by risk stratifying forearms into three groups-high, moderate, and low-risk of RHD.

Background: This systematic review aims to determine the best modality for the management of meniscal cysts and its associated meniscus tear; whether the meniscal cyst treated via arthroscopy or open methods and whether meniscal debridement or repair achieves better results. Methods: This systematic review was performed using PRISMA guidelines. A literature search of PubMed, EMBASE and Cochrane was carried out in July 2020 using the search terms 'meniscal cyst' and 'treatment'. All clinic studies that included filters for papers in the last 20 years, English language, and meniscal cysts found in humans were included. Studies that contained case reports, were in any language other than English, and with subjects that were not humans were excluded. The methodology quality assessment was performed through the modified Coleman methodology score (CMS). Results: A total of 166 results were obtained from PubMed, Cochrane library and EMBASE. Of them, 12 duplicates were identified across the databases and removed from consideration. Six papers were found relevant from EMBASE in which 1 was eventually included in this paper. In total, 12 papers were used in this study. The weighted mean age of the patients was 35.1 years, with total of 523 meniscal cysts, of which 488 of these cysts are associated with meniscal tears (93.31%). The studies included performed cystectomies and/ or decompression of meniscal cysts while some left the meniscal cyst alone and dealt with the meniscal lesion instead. All clinical scores showed significant improvement following surgical procedures. Conclusions: Both arthroscopic and open methods can be used for meniscal cysts treatment. Open cystectomy rather than decompression seemed to confer lower risk of cyst recurrences and complications. It is inconclusive to whether meniscal repair or meniscus debridement influenced recurrence and outcome scores. A recommendation for meniscus repair cannot be made due to insufficient high-quality level I or II trials.