Knee Osteotomy Decreases Joint Inflammation Based on Synovial Histology and Synovial Fluid Analysis.

PURPOSE: To examine the biological changes in the joints of patients with knee osteoarthritis (OA) before and after around-knee osteotomy (AKO), focusing on synovial fluid (SF) and synovial pathological changes. METHODS: Patients who underwent AKO for medial compartment knee OA between 2019 and 2021 were examined. SF and synovium were obtained at the time of AKO and plate removal after bone union (mean, 16.8 months [range: 11-38 months] postoperatively). SF volume and interleukin (IL)-6 concentrations in SF were assayed using enzyme-linked immunosorbent assay. Synovitis was assessed histologically using a semiquantitative scoring system. Macrophage infiltration was assessed by immunohistochemistry using a semiquantitative score for F4/80 expression. The M1/M2 ratio was calculated using percentage of cells positive for CD80 and CD163. The expression of proinflammatory cytokines was assessed by the percentage of IL-1ß- and IL-6-positive cells. The number of vascular endothelial growth factor-positive luminal structures was counted to assess angiogenesis. The change in each parameter was compared before and after AKO using the Wilcoxon matched-pairs signed-rank test. RESULTS: Twenty-four knees of 21 patients were included. SF volume and IL-6 concentration significantly decreased postoperatively (12.6 ± 2.1 mL vs 4.2 ± 0.6 mL; P < .0001 and 50.5 ± 8.6 pg/mL vs 20.7 ± 3.8 pg/mL; P = .0001, respectively). A significant reduction in synovitis score (P = .0001), macrophage infiltration (P < .0003), M1/M2 ratio (P < .0007), angiogenesis (P < .0001), and the percentage of IL-1ß- and IL-6-positive cells in the intima (P < .008 and P < .002, respectively) was found after AKO. CONCLUSIONS: SF volume and IL-6 concentrations in the SF decreased and inflammatory synovium pathology improved after AKO. In addition to biomechanical changes, the biological environment of the joint can be improved after AKO. LEVEL OF EVIDENCE: Level IV, retrospective therapeutic case series.

Decreased posterior tibial slope is a risk factor for primary posterior cruciate ligament rupture and posterior cruciate ligament reconstruction failure: A systematic review.

PURPOSE: To determine bony knee morphological factors associated with primary posterior cruciate ligament (PCL) rupture or PCL graft failure after PCL reconstruction. METHODS: Three databases, namely MEDLINE, PubMed and EMBASE, were searched on 30th May 2023. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data such as receiver operating characteristic curve parameters, as well as p-values for comparisons of values between patients with PCL pathology and control patients, were recorded. RESULTS: Nine studies comprising 1054 patients were included. Four studies reported that patients with PCL injury had flatter medial posterior tibial slopes (MTS) than controls, with mean values of 4.3 (range: 3.0-7.0) and 6.5 (range: 5.0-9.2) degrees, respectively. Two studies reported an MTS cutoff value ranging below 3.90-3.93° being a significant risk factor for primary PCL rupture or PCL graft failure. Two studies reported that shallow medial tibial depths were associated with primary PCL rupture, with mean values of 2.1 (range: 2.0-2.2) and 2.6 (range: 2.4-2.7) mm in PCL injury and control groups, respectively. Stenotic intercondylar notches and femoral condylar width were not consistently associated with PCL injuries. CONCLUSION: Decreased MTS is associated with primary PCL rupture and graft failure after PCL reconstruction with values below 3.93° being considered as a significant risk factor. Less common risk factors include shallow medial tibial depth, while femoral condylar width and parameters with regards to the intercondylar notch, such as notch width, notch width index and intercondylar notch volume, demonstrated conflicting associations with primary or secondary PCL injuries. LEVEL OF EVIDENCE: Level III.

Re-tear after arthroscopic rotator cuff tear surgery: risk analysis using machine learning.

BACKGROUND: Postoperative rotator cuff retear after arthroscopic rotator cuff repair (ARCR) is still a major problem. Various risk factors such as age, gender, and tear size have been reported. Recently, magnetic resonance imaging-based stump classification was reported as an index of rotator cuff fragility. Although stump type 3 is reported to have a high retear rate, there are few reports on the risk of postoperative retear based on this classification. Machine learning (ML), an artificial intelligence technique, allows for more flexible predictive models than conventional statistical methods and has been applied to predict clinical outcomes. In this study, we used ML to predict postoperative retear risk after ARCR. METHODS: The retrospective case-control study included 353 patients who underwent surgical treatment for complete rotator cuff tear using the suture-bridge technique. Patients who initially presented with retears and traumatic tears were excluded. In study participants, after the initial tear repair, rotator cuff retears were diagnosed by magnetic resonance imaging; Sugaya classification types IV and V were defined as re-tears. Age, gender, stump classification, tear size, Goutallier classification, presence of diabetes, and hyperlipidemia were used for ML parameters to predict the risk of retear. Using Python's Scikit-learn as an ML library, five different AI models (logistic regression, random forest, AdaBoost, CatBoost, LightGBM) were trained on the existing data, and the prediction models were applied to the test dataset. The performance of these ML models was measured by the area under the receiver operating characteristic curve. Additionally, key features affecting retear were evaluated. RESULTS: The area under the receiver operating characteristic curve for logistic regression was 0.78, random forest 0.82, AdaBoost 0.78, CatBoost 0.83, and LightGBM 0.87, respectively for each model. LightGBM showed the highest score. The important factors for model prediction were age, stump classification, and tear size. CONCLUSIONS: The ML classifier model predicted retears after ARCR with high accuracy, and the AI model showed that the most important characteristics affecting retears were age and imaging findings, including stump classification. This model may be able to predict postoperative rotator cuff retears based on clinical features.

Elicitation of Inhibitory Effects for AGE-Induced Oxidative Stress in Rotator Cuff-Derived Cells by Apocynin.

Advanced glycation end-products (AGEs) play a critical supportive role during musculoskeletal disorders via glycosylation and oxidative stress. Though apocynin, identified as a potent and selective inhibitor of NADPH oxidase, has been reported to be involved in pathogen-induced reactive oxygen species (ROS), its role in age-related rotator cuff degeneration has not been well clarified. Therefore, this study aims to evaluate the in vitro effects of apocynin on human rotator cuff-derived cells. Twelve patients with rotator cuff tears (RCTs) participated in the study. Supraspinatus tendons from patients with RCTs were collected and cultured. After the preparation of RC-derived cells, they were divided into four groups (control group, control + apocynin group, AGEs group, AGEs + apocynin group), and gene marker expression, cell viability, and intracellular ROS production were evaluated. The gene expression of NOX, IL-6, and the receptor for AGEs (RAGE) was significantly decreased by apocynin. We also examined the effect of apocynin in vitro. The results showed that ROS induction and increasing apoptotic cells after treatment of AGEs were significantly decreased, and cell viability increased considerably. These results suggest that apocynin can effectively reduce AGE-induced oxidative stress by inhibiting NOX activation. Thus, apocynin is a potential prodrug in preventing degenerative changes of the rotor cuff.

Development and Analysis of Mouse Medial Meniscus Posterior Root Tear Model.

Medial meniscus posterior root tears (MMPRT) are often associated with osteoarthritis (OA) progression and subchondral bone insufficiency fractures. This study aimed to develop the first MMPRT mouse model. The MMPRT model was created by sectioning the medial meniscus posterior root of 12-week-old CL57BL/6J male mice under stereomicroscopic observation. The sham operation and the destabilization of the medial meniscus (DMM) model groups were also created. OA progression and subchondral bone changes were evaluated histologically using the Osteoarthritis Research Society International (OARSI) subchondral bone scoring system at 2, 4, 8, and 12 weeks after surgery. Microcomputed tomography (µCT) was performed to evaluate the presence of insufficient fractures. OA progression and medial meniscus extrusion were observed in the MMPRT and DMM models 12 weeks after surgery. OA progressed in both models during the time course, without a significant difference in the OARSI score between the two groups. The subchondral bone score was significantly higher at 12 weeks than at 2 and 4 weeks in the MMPRT group, while no significant difference was found between the two groups. In the µCT analysis, destruction of the medial tibial plateau was observed in 4/40 knees, while none were observed in the DMM group. Of the four knees, destruction of the medial femoral condyle was also observed in three knees. Characteristic pathological changes were observed in the mouse MMPRT model. The mouse MMPRT model may be useful for investigating pathological changes after MMPRT.

Intra-articular site-specific distribution of advanced glycation end products in the shoulder of patients with diabetes mellitus having rotator cuff tears.

BACKGROUND: Advanced glycation end products (AGEs) are compounds formed due to aging and diabetes mellitus (DM). They activate NADPH oxidase (NOX) by binding to their receptors, thereby increasing the production of reactive oxygen species (ROS), which cause oxidative stress. In this study, we investigated the effects of AGEs on the tissues of the shoulder joint (such as rotator cuff synovium, and capsule) in patients with DM having rotator cuff tears. METHODS: This study included eight patients with DM who underwent surgical treatment for rotator cuff tears with contracture. The rotator cuff, synovium, and joint capsule were harvested at the time of surgery and evaluated by hematoxylin-eosin staining. Furthermore, immunostaining was used for evaluating AGEs and receptor for AGEs (RAGE), cell activity, ROS, and apoptosis. Quantitative real-time polymerase chain reaction (qPCR) was employed for the cellular evaluation of NOX, interleukins, RAGE, and collagen. RESULTS: The AGEs and RAGE staining as well as the ratio of ROS and apoptosis were in the following order: rotator cuff > joint capsule > synovium. In contrast, the cellular activity was significantly higher in the synovium than in the other regions. The type I collagen expression (as shown by qPCR) as well as the RAGE and NOX expressions were as follows: rotator cuff > joint capsule > synovium. Conversely, the expression of inflammatory cytokines (i.e., IL-6 and IL-1ß) was higher in the synovium than in the other regions. CONCLUSIONS: Our study is among the first to evaluate the effects of AGEs on each tissue of the shoulder joint in patients with DM having rotator cuff tears and contractures. The accumulation of AGEs in each tissue of the shoulder joint could reveal the locations affected by DM, which can lead to a better understanding of the pathophysiology of DM-related shoulder diseases.

Less than 1% risk of donor-site quadriceps tendon rupture post-ACL reconstruction with quadriceps tendon autograft: a systematic review.

PURPOSE: The purpose of this study is to develop a comprehensive complications profile for quadriceps tendon-autograft anterior cruciate ligament reconstruction (QT ACL-R). METHODS: A traditional and grey literature search was conducted in accordance with PRISMA and R-AMSTAR guidelines. PubMed, EMBASE, MEDLINE, CINAHL, Cochrane, Web of Science, and many grey literature sources were searched from inception to May 29, 2022. All studies were searched and screened in duplicate with included studies being of all levels of evidence, reporting complications, and with patients of all ages undergoing primary ACL reconstruction with quadriceps tendon autograft in the last 15 years. Studies were excluded if they had cadaveric or animal subjects or were reviews. Risk of bias assessment was conducted using MINORS criteria for non-randomised studies and Cochrane's RoB 2.0 for randomised studies. Data were summarised with weighted event rates generated under a random-effects model. RESULTS: A total of 55 studies (5315 reconstructions) were included: 32 used quadriceps tendon with bone block (B-QT), 19 used all-soft tissue quadriceps tendon (S-QT), and four did not report the QT graft subtype used. Included patients had an age range of 6.2-58 years and an average reported follow-up time of 28.1 months (range, 6-90 months) for non-randomised studies and 34.3 months (range, 0.233-120 months) for randomised studies. Pooled incidence rates for clinically relevant major complications included contralateral ACL injury at 6.0%, postoperative meniscal issues at 5.4%, cyclops lesions at 4.8%, graft failure at 4.1%, patellar fracture at 2.2%, hardware removal at 1.7%, infection at 1.5%, and donor-site quadriceps tendon rupture at 0.7%. Pooled incidence rates for clinically relevant minor complications included anterior knee pain at 9.7%, kneeling pain at 9.5%, sensation deficits at 4.4%, loss of extension at 4.2%, donor-site tendinopathy at 3.9%, cosmetic issues at 1.8%, and hematoma at 1.5%. CONCLUSIONS: QT ACL-R resembles other graft types in its rates and types of postoperative complications. In this exploratory systematic review, no complications of QT ACL-R were found to be disproportionately represented in the literature. This graft type should remain an option with comparable complication rates to other graft choices. LEVEL OF EVIDENCE: Level IV. REGISTRATION: This study was preregistered under PROSPERO with preregistration code CRD42022302078.

Anatomical double-bundle anterior cruciate ligament reconstruction moderately improved tegner scores over the long-term: a systematic review and meta-analysis of randomized controlled trials.

PURPOSE: To assess the effects of anatomical double-bundle (DB) versus single-bundle (SB) for anterior cruciate ligament (ACL) reconstruction in skeletally mature patients with ACL injuries. METHODS: MEDLINE, EMBASE, and CENTRAL were searched from inception to February 7, 2022 were screened for randomized controlled trials. The Anatomic Anterior Cruciate Ligament Reconstruction Checklist was used to categorize studies as anatomic. A random-effects meta-analysis was conducted, with pooled results being summarized using mean difference (MD). Risk of Bias (RoB) was assessed using the RoB 2.0 tool. Certainty of evidence was rated using GRADE. RESULTS: A search of 1371 unique articles yielded eight eligible trials, representing 735 patients (360 DB, 375 SB) with mean (SD) age of 28.5 (2.86) years and follow-up of 52.1 (36.2) months. Most trials had moderate to low RoB. Overall, DB was not significantly better than SB on Lysholm scores (MD = 0.52, 95% CI, - 1.80-2.85, p = 0.66; moderate certainty) or subjective International Knee Documentation Committee (IKDC) scores (MD = - 0.40, 95% CI, - 4.35-3.55, p = 0.84; moderate certainty). Tegner scores were significantly higher in SB than DB in the intermediate term (MD = - 0.72, 95% CI, - 1.10 to - 0.34, p = 0.0002; high certainty), while significantly higher in DB relative to SB in the long-term (MD = 0.52, 95% CI, 0.02-1.03, p = 0.04; high certainty). CONCLUSION: DB ACL reconstruction significantly improves Tegner scores relative to SB ACL reconstruction over the long-term (t ≥ 5 years). Intermediate term Tegner scores favour SB reconstruction. In both durations, there was no clinically significant difference based on the pre-specified minimal clinically important difference of 1.0 point. There were also no significant differences in IKDC or Lysholm scores. Surgeons should consider anatomical DB ACL reconstruction as a result of long-term improvement in patient-reported outcomes. LEVEL OF EVIDENCE: I.

Tibial tubercle to trochlear groove distance versus tibial tubercle to posterior cruciate ligament distance for predicting patellar instability: a systematic review.

PURPOSE: To determine the reliability and diagnostic accuracy of tibial tubercle-trochlear groove (TT-TG) distance versus tibial tubercle-posterior cruciate ligament (TT-PCL) distance, and to determine cutoff values of these measurements for pathological diagnosis in the context of patellar instability. METHODS: Three databases MEDLINE, PubMed and EMBASE were searched from inception to October 5, 2022 for literature outlining comparisons between TT-TG and TT-PCL in patellar instability patients. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on inter-rater and intra-rater reliability, receiver-operating characteristic (ROC) curve parameters such as area under the curve (AUC), sensitivity and specificity, as well as odds ratios, cutoff values for pathological diagnosis and correlations between TT-TG and TT-PCL were recorded. The MINORS score was used for all studies in order to perform a quality assessment of included studies. RESULTS: A total of 23 studies comprising 2839 patients (2922 knees) were included in this review. Inter-rater reliability ranged from 0.71 to 0.98 and 0.55 to 0.99 for TT-TG and TT-PCL, respectively. Intra-rater reliability ranged from 0.74 to 0.99 and 0.88 to 0.98 for TT-TG and TT-PCL, respectively. AUC measuring diagnostic accuracy of patellar instability for TT-TG ranged from 0.80 to 0.84 and 0.58 to 0.76 for TT-PCL. Five studies found TT-TG to have more discriminatory power than TT-PCL at distinguishing patients with patellar instability from patients who do not. Sensitivity and specificity ranged from 21 to 85% and 62 to 100%, respectively, for TT-TG. Sensitivity and specificity ranged from 30 to 76% and 46 to 86%, respectively, for TT-PCL. Odds ratio values ranged from 1.06 to 14.02 for TT-TG and 0.98 to 6.47 for TT-PCL. Proposed cutoff TT-TG and TT-PCL values for predicting patellar instability ranged from 15.0 to 21.4 mm and 19.8 to 28.0 mm, respectively. Eight studies reported significant positive correlations between TT-TG and TT-PCL. CONCLUSION: TT-TG resulted in overall similar reliability, sensitivity and specificity as TT-PCL; however, TT-TG has better diagnostic accuracy than TT-PCL in the context of patellar instability as per AUC and odds ratio values. LEVEL OF EVIDENCE: Level IV.

Though five-strand hamstring autografts demonstrate greater graft diameter, postoperative outcomes are equivocal to four-strand hamstring autograft preparations: a systematic review and meta-analysis of level I and II studies.

PURPOSE: To compare graft dimensions, functional outcomes, and failure rates following anterior cruciate ligament reconstruction (ACLR) with either five-strand or four-strand hamstring autograft options. METHODS: Three databases (MEDLINE, PubMed, and EMBASE) were searched from inception to 22 April 2023 for level I and II studies comparing five- and four-strand hamstring autografts in ACLR. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, surgical details and rehabilitation, graft diameter, patient-reported outcome measures (PROMs), and rates of positive Lachman test, positive pivot shift test, and graft rupture were extracted. PROMs included Knee Osteoarthritis and Outcome Score (KOOS) subscales, Lysholm, and International Knee Documentation Committee (IKDC). RESULTS: One randomized controlled trial (RCT) and four prospective cohort studies with 572 patients were included. Graft diameters were larger in the five-strand group with a mean difference of 0.93 mm (95% CI 0.61 to 1.25, p < 0.001, I2 = 66%). The five-strand group reported statistically higher KOOS ADL subscale and Lysholm scores with a mean difference of 4.85 (95% CI 0.14 to 9.56, p = 0.04, I2 = 19%) and 3.01 (95% CI 0.48 to 5.53, p = 0.02, I2 = 0%), respectively. There were no differences in KOOS symptoms, pain, quality of life, or sports subscales, or IKDC scores. There were no differences in rates of positive Lachman test, positive pivot shift test, or graft rupture with pooled odds ratios of 0.62 (95% CI 0.13 to 2.91, n.s., I2 = 80%), 0.94 (95% CI 0.51 to 1.75, n.s., I2 = 31%), and 2.13 (95% CI 0.38 to 12.06, n.s., I2 = 0%), respectively. CONCLUSIONS: Although five-stranded hamstring autografts had significantly larger graft diameters compared to four-stranded grafts with a mean difference of 0.93 mm, similar graft rupture rates and clinical laxity assessments were identified following ACLR. While some PROMs were statistically superior in the five-stranded hamstring groups, the threshold for the minimal clinical important difference was not reached indicating similar clinical outcomes overall. LEVEL OF EVIDENCE: Level II.

Partial debridement is the most commonly reported treatment option for mucoid degeneration of the anterior cruciate ligament: a systematic review.

PURPOSE: To determine clinical outcomes and risks of various management strategies for mucoid degeneration of the anterior cruciate ligament (MD-ACL). METHODS: Three databases MEDLINE, PubMed and EMBASE were searched from inception to January 29th, 2023 for literature outlining clinical outcomes for various management strategies of MD-ACL. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on satisfaction scores, visual analogue scale (VAS) scores, Lysholm scores, International Knee Documentation Committee (IKDC) scores, Knee Osteoarthritis and Outcome Scores (KOOS), range of motion and Lachman test were recorded. RESULTS: A total of 14 studies comprising 776 patients (782 knees) were included in this review. Partial debridement was reported in ten (71.4%) studies comprising 446 patients, showing significant improvements in VAS, Lysholm, IKDC scores and range of motion. Complete debridement was reported by two (14.2%) studies comprising 250 patients, and resulted in increases in Lysholm scores, KOOS, and range of motion. Reduction plasty was reported in two (14.2%) studies comprising 26 patients and showed improvements in VAS and Lysholm scores, and range of motion. Other methods of treatment included conservative management and ultrasound decompression. Complete debridement resulted in 10/23 (43%) patients with a positive Lachman test. This was followed by reduction plasty and partial debridement, with 5/26 (19.2%) and 45/340 (13.2%) patients respectively having positive Lachman or elevated knee arthrometer scores. Pivot shifting was only reported in studies on partial debridement and reduction plasty, with 14/93 (15.1%) and 1/21 (4.8%) patients have positive results, respectively. CONCLUSION: The most commonly reported management strategy for MD-ACL is partial debridement with complete debridement, reduction plasty and conservative management as alternative options. Current operative management strategies place individuals at risk for ACL insufficiency. Information from this review can aid surgeons and clinicians in understanding what treatment options are best for this patient population, by understanding the reported clinical benefits and risks of each strategy. LEVEL OF EVIDENCE: IV.

Technology-assisted anterior cruciate ligament reconstruction improves tunnel placement but leads to no change in clinical outcomes: a systematic review and meta-analysis.

PURPOSE: To investigate the effect of technology-assisted Anterior Cruciate Ligament Reconstruction (ACLR) on post-operative clinical outcomes and tunnel placement compared to conventional arthroscopic ACLR. METHODS: CENTRAL, MEDLINE, and Embase were searched from January 2000 to November 17, 2022. Articles were included if there was intraoperative use of computer-assisted navigation, robotics, diagnostic imaging, computer simulations, or 3D printing (3DP). Two reviewers searched, screened, and evaluated the included studies for data quality. Data were abstracted using descriptive statistics and pooled using relative risk ratios (RR) or mean differences (MD), both with 95% confidence intervals (CI), where appropriate. RESULTS: Eleven studies were included with total 775 patients and majority male participants (70.7%). Ages ranged from 14 to 54 years (391 patients) and follow-up ranged from 12 to 60 months (775 patients). Subjective International Knee Documentation Committee (IKDC) scores increased in the technology-assisted surgery group (473 patients; P = 0.02; MD 1.97, 95% CI 0.27 to 3.66). There was no difference in objective IKDC scores (447 patients; RR 1.02, 95% CI 0.98 to 1.06), Lysholm scores (199 patients; MD 1.14, 95% CI - 1.03 to 3.30) or negative pivot-shift tests (278 patients; RR 1.07, 95% CI 0.97 to 1.18) between the two groups. When using technology-assisted surgery, 6 (351 patients) of 8 (451 patients) studies reported more accurate femoral tunnel placement and 6 (321 patients) of 10 (561 patients) studies reported more accurate tibial tunnel placement in at least one measure. One study (209 patients) demonstrated a significant increase in cost associated with use of computer-assisted navigation (mean 1158€) versus conventional surgery (mean 704€). Of the two studies using 3DP templates, production costs ranging from $10 to $42 USD were cited. There was no difference in adverse events between the two groups. CONCLUSION: Clinical outcomes do not differ between technology-assisted surgery and conventional surgery. Computer-assisted navigation is more expensive and time consuming while 3DP is inexpensive and does not lead to greater operating times. ACLR tunnels can be more accurately located in radiologically ideal places by using technology, but anatomic placement is still undetermined because of variability and inaccuracy of the evaluation systems utilized. LEVEL OF EVIDENCE: Level III.

Patients with discoid menisci have similar clinical outcomes to those without discoid menisci when undergoing surgical intervention: a systematic review.

PURPOSE: To compare post-operative clinical outcomes of discoid meniscus tear procedures such as saucerization with or without repair with those of non-discoid meniscus tears such as meniscectomy or repair in skeletally mature patients with no concomitant injuries. METHODS: Three databases MEDLINE, PubMed and EMBASE were searched from inception to July 3rd, 2022 for literature describing patient-reported outcome measures after meniscus surgery in discoid or non-discoid meniscus tears. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Clinical outcome data on Lysholm, Tegner, International Knee Documentation Committee (IKDC), revision rates, and complications were recorded, with MINORS and Detsky scores used for quality assessment. RESULTS: A total of 38 studies comprising 2213 patients were included with a mean age of 38.6 years (range: 9.0-64.4). The mean follow-up time was 54.1 months (range: 1-234) and the average percentage of female participants was 46.8% (range: 9.5-95.5). The mean change between pre-operative and post-operative Lysholm scores ranged from 21.0-39.0, 7.4-24.1, and 24.2-48.4 in the discoid, non-discoid meniscectomy, and non-discoid repair groups, respectively. The mean change in Tegner scores ranged from 0.0 to 2.3, 1.3, and 0.4-1.3 in the discoid, non-discoid meniscectomy, and non-discoid repair groups, respectively. Pre-operative IKDC scores were not reported, however mean post-operative IKDC scores ranged from 77.4 to 96.0, 46.9 to 85.7, and 63.1 to 94.0 in discoid, non-discoid meniscectomy, and non-discoid repair groups, respectively. Revision rates for discoid procedures, non-discoid meniscectomies, and non-discoid meniscus repairs ranged from 3.2 to 44.0%, 8.3 to 56.0%, and 5.9 to 28.0%, respectively. The most common reasons for revision were acute trauma and persistent pain. CONCLUSION: Discoid saucerization procedures with or without repair leads to similar Lysholm scores as non-discoid repair procedures, and similar IKDC scores and revision rates compared to non-discoid meniscectomy or repair procedures. Patients undergoing discoid procedures appeared to have slightly higher Tegner activity scores compared to patients undergoing non-discoid procedures; however this is to be considered in the context of a younger population of patients undergoing discoid procedures than non-discoid procedures. This information can help guide surgeons in the decision-making process when treating patients with discoid menisci, and should guide further investigations on this topic. LEVEL OF EVIDENCE: IV.

Combining age, sex, body mass index, sport level, and preoperative quadriceps strength improves the predictive ability of quadriceps strength recovery after anterior cruciate ligament reconstruction.

PURPOSE: This study compared the predictive ability of each independent predictor with that of a combination of predictors for quadriceps strength recovery one year after anterior cruciate ligament (ACL) reconstruction. METHODS: Patients who underwent primary ACL reconstruction using hamstring autografts were enrolled. Quadriceps strength, hamstring strength, and anterior tibial translation were measured, and the limb symmetry index (LSI) of the quadriceps and the hamstrings was calculated preoperatively and one year after surgery. Patients were classified into two groups according to the LSI of the quadriceps strength at one year postoperatively (≥ 80% or < 80%). Multivariate logistic regression analysis identified the independent predictors of quadriceps strength recovery, and the cut-off value was calculated using the receiver operating characteristic curve. A model assessing predictive ability of the combination of independent predictors was created, and the area under the curve (AUC) for each independent predictor was calculated by using the receiver-operating characteristic curves and the DeLong method. RESULTS: Of the 646 patients, 414 (64.1%) had an LSI of at least 80% for quadriceps strength one year after surgery, and 232 patients (35.9%) had an LSI of < 80%. Age, sex, body mass index (BMI), preinjury sport level, and LSI of preoperative quadriceps strength were independently associated with quadriceps strength recovery one year after ACL reconstruction. The cut-off values were age: 22.5 years; sex: female; BMI: 24.3 kg/m2; preinjury sport level: no sport; and LSI of preoperative quadriceps strength: 63.3%. The AUC of the model assessing the predictive ability of the combination of age, sex, BMI, preinjury sport level, and LSI of preoperative quadriceps strength was significantly higher (0.73) than that of similar factors of preoperative quadriceps strength (AUC: 0.63, 0.53, 0.56, 0.61, and 0.68, p < 0.01, respectively). CONCLUSION: The combination of age, sex, BMI, preinjury sport level, and LSI of preoperative quadriceps strength had a superior predictive ability for quadriceps strength recovery at one year after ACL reconstruction than these predictors alone. Multiple factors, including patient characteristics and preoperative quadriceps strength, should be considered when planning rehabilitation programs to improve quadriceps strength recovery after ACL reconstruction. LEVEL OF EVIDENCE: III.

Contralateral hamstring autografts do not provide benefit compared to ipsilateral hamstring autografts in primary or revision anterior cruciate ligament reconstruction: a systematic review.

PURPOSE: To evaluate the clinical outcomes of primary or revision ACL reconstruction (ACLR) after contralateral hamstring autografts versus ipsilateral hamstring autograft harvest. METHODS: Three databases (MEDLINE, PubMed and EMBASE) were searched from inception to April 27th, 2023 for studies investigating contralateral hamstring autografts in primary or revision ACLR. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, strength measures, patient-reported outcome measures (PROMs), and rates of positive Lachman test, positive pivot-shift test and graft rupture were extracted. PROMs included Lysholm, International Knee Documentation Committee (IKDC) and Tegner scores. RESULTS: Nine studies comprising 371 patients were included in this review. In primary ACLR, there were no significant differences between contralateral and ipsilateral groups in isokinetic hamstring torque in the non-ACLR limb or isokinetic quadriceps torque in both limbs when tested at 60, 90, 120 or 180 degrees/second. Isokinetic hamstring torque in the non-ACLR limb was significantly weaker in the contralateral group at six months for primary ACLR; however, these deficits did not persist. There were no significant differences in postoperative median Tegner scores and Lysholm scores between contralateral and ipsilateral groups in primary ACLR. There were no significant differences in postoperative median Tegner, mean Lysholm and IKDC scores between groups in revision ACLR. There were no significant differences in positive Lachman, positive pivot-shift and rupture rates in primary ACLR between groups. Rates of positive Lachman and pivot-shift were slightly higher in the contralateral than ipsilateral group for revision ACLR. CONCLUSION: Contralateral hamstring autografts results in comparable muscle strength to ipsilateral hamstring autografts, with the exception of weaker hamstring strengths in the early postoperative period. Patient-reported outcome measures were similar between the two groups across both primary and revision ACLR, with rates of instability and failure being similar between groups for primary ACLR. Contralateral hamstring grafts do not provide additional benefit when compared to ipsilateral options for either primary or revision ACLR, and should be used only in select circumstances including insufficient ipsilateral hamstring grafts or situations where quadriceps or patella autografts are not optimal. LEVEL OF EVIDENCE: Level IV.

Risk factors of residual pivot-shift after anatomic double-bundle anterior cruciate ligament reconstruction.

INTRODUCTION: Although anterior cruciate ligament reconstruction (ACLR) is considered a successful procedure, residual pivot-shift after surgery remains to be solved. The purpose of this study was to comprehensively evaluate the risk factors of residual pivot-shift after anatomic double-bundle (DB) ACLR. MATERIALS AND METHODS: A total of 164 patients who underwent primary anatomic DB-ACLR between January 2014 and December 2019 and screw removal after the index ACLR in our hospital were included in this retrospective case-control study. The manual pivot-shift test was performed under general anesthesia during screw removal surgery, and patients with grade 1 or higher pivot-shift were classified as the positive pivot-shift group, and those with grade 0 were defined as the negative pivot-shift group. Univariate and logistic regression analyses were performed to identify the factors associated with postoperative residual pivot-shift. Assessment included sex, age, time to surgery, preoperative Tegner activity scale, preoperative pivot-shift grade, preoperative anterior tibial translation by the KT-2000 arthrometer measurement, meniscus injury and its surgical procedure, knee hyperextension, cartilage damage, Segond fracture, medial and lateral posterior tibial slope, lateral-medial slope asymmetry, participation in pivoting sport/activity at the time of injury, and return to sports at postoperative one year line. RESULTS: Postoperative positive pivot-shift was observed in 14 (8.5%) of 164 patients. The KT-2000 measurement at 1-year postoperatively was significantly higher in the residual pivot-shift-positive group than in the negative group (P < 0.05). Logistic regression analysis revealed that age of patients < 20 years [P < 0.05, odds ratio (OR): 6.1)], preoperative pivot-shift grade (P < 0.05, OR: 4.4), and hyperextended knee (P < 0.05, OR: 11.8) were risk factors of postoperative pivot-shift. There were no statistically significant differences between other variables. CONCLUSIONS: Patients < 20 years of age, with high-grade preoperative pivot-shift, or hyperextended knees had a higher risk of residual postoperative pivot-shift.

Talar component subsidence correlates with periprosthetic osteolysis after total ankle arthroplasty.

PURPOSE: This study aimed to investigate the relationship between periprosthetic osteolysis around the talar component and the amount of talar component subsidence after total ankle arthroplasty (TAA). METHODS: This study included forty patients who underwent TAA with a mean follow-up of 67.5 ± 17.0 months. The patients were divided into two groups based on the amount of osteolysis around the talar component, as measured by computed tomography at the latest clinic visit: none to 2 mm (N group, n = 20) and greater than or equal to 2 mm (O group, n = 20). The average amount of talar component subsidence, clinical outcomes, and complications were compared between the two groups. In the O group, the correlation between osteolysis and talar component subsidence was evaluated. RESULTS: The average talar component subsidence was significantly different between the N (0.22 ± 0.94 mm) and O groups (2.12 ± 2.28 mm). Five out of 20 ankles in the O group required revision surgery owing to talar component subsidence. The Japanese Society for Surgery of the Foot scores in the N and O groups were significantly different: 93.5 ± 7.7 and 85.3 ± 15.4, respectively. In the O group, we found that osteolysis tended to develop on the lateral side, and the amount of osteolysis was positively correlated with the talar component subsidence (r = 0.59, P = .007). CONCLUSION: In the O group, a positive correlation between osteolysis and talar component subsidence was found, and five patients required revision surgery.

Antioxidant effect of nicotinamide mononucleotide in tendinopathy.

BACKGROUND: A link between tendinopathy and oxidative stress has been recently reported. Nicotinamide mononucleotide (NMN) is a precursor of nicotinamide adenine dinucleotide, which plays an important role in cell redox homeostasis. The aim of this study was to evaluate the antioxidant effect of NMN on tendinopathy in vitro and in vivo. METHODS: Tenocytes from healthy Sprague-Dawley rats were cultured in regular glucose (RG) and high-glucose (HG) conditions with or without NMN, and were divided into four groups: RG NMN(-), RG NMN(+), HG NMN(-), and HG NMN(+). Cell viability, reactive oxygen species (ROS) accumulation, apoptotic rate, and mRNA expression of nicotinamide adenine dinucleotide phosphate oxidase (NOX)1, NOX4, interleukin (IL)6, sirtuin (SIRT)1, and SIRT6 were investigated. In addition, rats with collagenase-induced tendinopathy were treated with or without NMN. Immunostaining of NOX1 and NOX4; mRNA expression of SIRT1, SIRT6, and IL6; and superoxide dismutase (SOD) activity measurements in the Achilles tendon were performed. RESULTS: NMN increased the expression of SIRT1 and SIRT6 in rat tenocytes, but decreased the levels of NOX1, NOX4, IL6, ROS, and apoptosis. In Achilles tendons with collagenase-induced tendinopathy, NMN increased the mRNA expression of SIRT1 and SIRT6, as well as SOD activity; while suppressing protein expression of NOX1 and NOX4, and mRNA expression of IL6. CONCLUSION: The in vitro and in vivo results of this study show that NMN exerts an antioxidant effect on tendinopathy by promoting the expression of SIRT while inhibiting that of NOX.

Advanced glycation end products are associated with limited range of motion of the shoulder joint in patients with rotator cuff tears associated with diabetes mellitus.

BACKGROUND: Most degenerative rotator cuff tears (RCTs) are associated with a limited range of motion (ROM) of the shoulder joint. Additionally, patients with diabetes mellitus (DM) show a higher frequency of limited ROM. Recently, advanced glycation end products (AGEs) of proteins have been observed to cause tissue fibrosis, primarily through abnormal collagen cross-linking and oxidative stress. In this study, we investigated the effect of AGEs on ROM limitation in the shoulder capsule and its relationship with DM in the patients with RCTs. METHODS: Sixteen patients (eight in the DM and non-DM groups) who underwent arthroscopic surgery for RCT with limited shoulder ROM were included in this study. AGE-related pathologies in both groups were compared, and the relationship between AGE accumulation and shoulder joint ROM was evaluated. Shoulder capsule tissue was harvested and subjected to histological and in vitro evaluation. RESULTS: The DM group displayed high levels of AGEs and reactive oxygen species (ROS), and reduced cell viability. There was a significant positive correlation between ROS expression, apoptosis, and preoperative hemoglobin A1c. ROS expression, apoptosis, and ROM of the shoulder joint showed a negative correlation. The NADPH oxidase (NOX) expression and collagen III/I ratio were significantly higher in the DM group than in the non-DM group. CONCLUSIONS: The DM group showed significant AGEs deposition in the shoulder capsule. Additionally, there was a significant association between AGEs and ROM limitation. Collectively, the findings suggest that the oxidative stress induced by AGEs deposition, which leads to fibrosis and local inflammation, might contribute to the limited ROM of the shoulder joint in patients with RCTs accompanied by DM.

The coronal lateral collateral ligament sign in the anterior cruciate ligament-injured knees was observed regardless of the knee laxity based on the quantitative measurements.

PURPOSE: The coronal lateral collateral ligament (LCL) sign has been reported to be associated with deviated position of the tibia on MRI due to anterior cruciate ligament (ACL) injuries. However, the relationships between LCL sign and clinical knee laxity evaluations are still unclear. The purpose of the study was to investigate the relationship between the coronal LCL sign and knee laxity measurements. METHODS: A retrospective review of unilateral ACL injured patients who underwent ACL reconstruction was performed. The coronal LCL sign was determined using magnetic resonance imaging (MRI). Clinical grading of the pivot-shift test, KT-1000 measurements, and quantitative measurements of the Lachman test and the pivot-shift test using an electromagnetic system, were compared between patients with positive and negative coronal LCL sign. A subgroup analysis of different age groups was then performed, dividing patients to adolescent (age ≤ 18 years) and adult (age > 18 years) groups. RESULTS: A total of 85 patients were enrolled, of which 45 patients had coronal LCL signs. The coronal LCL sign was not associated with the pivot-shift test clinical grading (n.s), KT-1000 measurement (n.s), the tibial translation during the Lachman test (n.s), or with tibia acceleration (n.s) and translation (n.s) during the pivot-shift test. The subgroup analysis also showed that the aforementioned parameters were not associated with the coronal LCL sign in either adolescent or adult subgroups. CONCLUSION: The occurrence of coronal LCL sign in MRI did not imply greater clinical knee laxity evaluations in patients with ACL tears. The knee laxity should routinely be evaluated regardless the coronal LCL sign. LEVEL OF EVIDENCE: Level III.