Artificial Intelligence-Based Emphysema Quantification in Routine Chest Computed Tomography: Correlation With Spirometry and Visual Emphysema Grading.

OBJECTIVE: The aim of the study is to assess the correlation between artificial intelligence (AI)-based low attenuation volume percentage (LAV%) with forced expiratory volume in the first second to forced vital capacity (FEV1/FVC) and visual emphysema grades in routine chest computed tomography (CT). Furthermore, optimal LAV% cutoff values for predicting a FEV1/FVC < 70% or moderate to more extensive visual emphysema grades were calculated. METHODS: In a retrospective study of 298 consecutive patients who underwent routine chest CT and spirometry examinations, LAV% was quantified using an AI-based software with a threshold < -950 HU. The FEV1/FVC was derived from spirometry, with FEV1/FVC < 70% indicating airway obstruction. The mean time interval of CT from spirometry was 3.87 ± 4.78 days. Severity of emphysema was visually graded by an experienced chest radiologist using an established 5-grade ordinal scale (Fleischner Society classification system). Spearman correlation coefficient between LAV% and FEV1/FVC was calculated. Receiver operating characteristic determined the optimal LAV% cutoff values for predicting a FEV1/FVC < 70% or a visual emphysema grade of moderate or higher (Fleischner grade 3-5). RESULTS: Significant correlation between LAV% and FEV1/FVC was found (ϱ = -0.477, P < 0.001). Increasing LAV% corresponded to higher visual emphysema grades. For patients with absent visual emphysema, mean LAV% was 2.98 ± 3.30, for patients with trace emphysema 3.22 ± 2.75, for patients with mild emphysema 3.90 ± 3.33, for patients with moderate emphysema 6.41 ± 3.46, for patients with confluent emphysema 9.02 ± 5.45, and for patients with destructive emphysema 16.90 ± 8.19. Optimal LAV% cutoff value for predicting a FEV1/FVC < 70 was 6.1 (area under the curve = 0.764, sensitivity = 0.773, specificity = 0.665), while for predicting a visual emphysema grade of moderate or higher, it was 4.7 (area under the curve = 0.802, sensitivity = 0.766, specificity = 0.742). Furthermore, correlation between visual emphysema grading and FEV1/FVC was found. In patients with FEV1/FVC < 70% a high proportion of subjects had emphysema grade 3 (moderate) or higher, whereas in patients with FEV1/FVC ≥ 70%, a larger proportion had emphysema grade 3 (moderate) or lower. The sensitivity for visual emphysema grading predicting a FEV1/FVC < 70% was 56.3% with an optimal cutoff point at a visual grade of 4 (confluent), demonstrating a lower sensitivity compared with LAV% (77.3%). CONCLUSIONS: A significant correlation between AI-based LAV% and FEV1/FVC as well as visual CT emphysema grades can be found in routine chest CT suggesting that AI-based LAV% measurement might be integrated as an add-on functional parameter in the evaluation of chest CT in the future.

Quality of YouTube Videos Regarding Anterior Cruciate Ligament Reconstruction Using Quadriceps Tendon Autograft Is Unsatisfactory.

PURPOSE: To assess the validity and informational value of teaching material regarding anterior cruciate ligament reconstruction (ACLR) using quadriceps tendon (QT) autograft provided on the YouTube video platform. METHODS: An extensive systematic search of the YouTube video platform was performed, and all videos that met the criteria were included in the analysis. The analysis of the video content was performed using the DISCERN instrument, Journal of American Medical Association (JAMA) benchmark criteria, and Global Quality Score (GQS). The duration of the videos, the date of publication, and the number of likes and views were recorded. Furthermore, videos were categorized based on the source (physicians, companies, patients), the subject (surgical technique, patient experience and overview [overview videos were videos in which multiple aspects were analyzed]), and the type of content (educational or subjective patient experience). RESULTS: A total of 88 videos were included in the analysis. Seventy-one (80.7%) videos were published by physicians, 15 (17.0%) by patients, and 2 (2.3%) by companies. The majority of the videos described various surgical techniques (59%-67.0%), 80.7% of the videos (72%-81.8%) had an educational nature, and the remaining 18.2% described patient experiences. The mean length of the videos was 8.21 ± 7.88 minutes. The mean number of views was 3,988.51 ± 9,792.98 (range 9-56,047), whereas the mean numbers of comments and likes were 30.07 ± 70.07 (range 0-493) and 4.48 ± 14.22 (range 0-82), respectively. The mean DISCERN score, JAMA score, and GQS were 27.43 ±11.56 (95% confidence interval [CI] 25.01-29.85; range: 17-68), 1.22 ± 0.85 (95% CI 1.04-1.40; range 0-3), and 1.82 ± 0.93 (95% CI 1.63-2.01; range 1-4), respectively. For all scores, videos published by physicians had greater quality (DISCERN score, JAMA score, and GQS) (P < .05). Among all of the analyzed videos, overview videos were of the highest quality (P < .05). CONCLUSIONS: YouTube is a fast and open-access source of mass information. The overall quality of the videos on ACLR performed using QT autograft was unsatisfactory, demonstrating low educational quality and reliability. Currently, YouTube cannot be recommended as a reliable source of information on ACLR with the QT.

Medial Patellofemoral Ligament Reconstruction Using Pedicled Quadriceps Tendon Autograft Yields Similar Clinical and Patient-Reported Outcomes but Less Donor-Site Morbidity Compared With Gracilis Tendon Autograft.

PURPOSE: To compare clinical and patient-reported outcome measures (PROMs) in patients with recurrent patellar dislocation after medial patellofemoral ligament (MPFL) reconstruction using either a gracilis tendon (GT) or quadriceps tendon autograft (QT). METHODS: All MPFL reconstruction performed between 2017 and 2019 were reviewed retrospectively. Only patients with isolated MPFL reconstruction, without any major patellofemoral risk factors and a minimum follow-up of 24 months, were included in the study. Patients were matched with respect to sex, age, and body mass index. All patients were evaluated clinically and using PROMs. RESULTS: A total of 64 patients with an average follow up of 28.7 ± 7.5 months were included in this study. The mean Kujala score (GT: 84.8 ± 12.9, QT: 88.9 ± 10.1), Lysholm score (GT: 89.4 ± 10.2, QT: 88.4 ± 5.0), and visual analog scale score for pain (GT: 1.9 ± 1.8, QT: 1.1 ± 1.3) did not significantly differ between both groups. Tegner activity level was significantly greater (P = .027) in the QT group (5.5 ± 1.9) compared with the GT group (4.6 ± 1.8), but within the minimal clinically important differences. Occasional patellar instability events, but no recurrent dislocation, were reported in 12.5% in the GT group and 6.3% in the QT group (P = .39). Of all patients, 90.6% in the QT and 68.8% in the HT group exceeded the PASS for the Kujala score (P = .06). Significantly more patients (59.4%) treated with GT reported donor-site morbidity in the form of sensitivity deficit at the lower leg compared with those treated with QT (3.1%, P = .001). CONCLUSIONS: GT and QT MPFL reconstruction have comparable PROMs and patellar redislocation rates 2 years' postoperatively. Significantly more patients treated with GT reported lower-leg sensitivity deficit compared with those treated with QT. LEVEL OF EVIDENCE: Level III, retrospective case-control study.

The Targeted Deletion of Genes Responsible for Expression of the Mth60 Fimbriae Leads to Loss of Cell-Cell Connections in Methanothermobacter thermautotrophicus ΔH.

This study is a continuation by the Environmental Biotechnology Group of the University of Tübingen in memoriam to Reinhard Wirth, who initiated the work on Mth60 fimbriae at the University of Regensburg. Growth in biofilms or biofilm-like structures is the prevailing lifestyle for most microbes in nature. The first crucial step to initiate biofilms is the adherence of microbes to biotic and abiotic surfaces. Therefore, it is crucial to elucidate the initial step of biofilm formation, which is generally established through cell-surface structures (i.e., cell appendages), such as fimbriae or pili, that adhere to biotic and abiotic surfaces. The Mth60 fimbriae of Methanothermobacter thermautotrophicus ΔH are one of only a few known archaeal cell appendages that do not assemble via the type IV pili assembly mechanism. Here, we report the constitutive expression of Mth60 fimbria-encoding genes from a shuttle-vector construct and the deletion of the Mth60 fimbria-encoding genes from the genomic DNA of M. thermautotrophicus ΔH. For this, we expanded our system for genetic modification of M. thermautotrophicus ΔH using an allelic-exchange method. While overexpression of the respective genes increased the number of Mth60 fimbriae, deletion of the Mth60 fimbria-encoding genes led to a loss of Mth60 fimbriae in planktonic cells of M. thermautotrophicus ΔH compared to the wild-type strain. This, either increased or decreased, number of Mth60 fimbriae correlated with a significant increase or decrease of biotic cell-cell connections in the respective M. thermautotrophicus ΔH strains compared to the wild-type strain. IMPORTANCE Methanothermobacter spp. have been studied for the biochemistry of hydrogenotrophic methanogenesis for many years. However, a detailed investigation of certain aspects, such as regulatory processes, was impossible due to the lack of genetic tools. Here, we amend our genetic toolbox for M. thermautotrophicus ΔH with an allelic exchange method. We report the deletion of genes that encode the Mth60 fimbriae. Our findings provide the first genetic evidence of whether the expression of these genes underlies regulation and reveal a role of the Mth60 fimbriae in the formation of cell-cell connections of M. thermautotrophicus ΔH.

Influence of contrast agent on artificial intelligence-based CT low attenuation volume percentage measurement.

BACKGROUND: Low attenuation volume percentage (LAV%) has been identified as a quantitative imaging biomarker for emphysema with good correlation with spirometry. The influence of intravenous contrast agent on LAV% and its correlation with spirometry is not well known. PURPOSE: To evaluate the influence of intravenous contrast agent on artificial intelligence (AI)-based LAV% in correlation with spirometric Tiffeneau-Pinelli Index (TI). MATERIAL AND METHODS: In a retrospective study, two groups of 47 patients (mean age 68.04 ± 12.64 and 67.89 ± 11.54 years) with either non-enhanced chest computed tomography (CT) or contrast-enhanced CT were compared. Using an AI-based software, LAV% was quantified using a threshold <-950 HU. TI was calculated from spirometry and pathologic airway obstruction was considered with a TI <70. The effect of contrast agent on LAV% and the relationship between TI and LAV% was analyzed. Correlation coefficients between TI and LAV% were compared for both groups. RESULTS: Patients with non-enhanced CT had a mean LAV% of 9.07 ± 7.53. Of them, 22 patients had a TI <70% and 25 patients a TI ≥70%. Patients with contrast-enhanced CT had a mean LAV% of 6.54 ± 4.62. Of them, 20 patients had a TI <70% and 27 patients had a TI ≥70%. Contrast agent did not show a major effect on LAV% (P = 0.099) and the relationship between TI and LAV% (P = 0.88). In both groups, a significant correlation between TI and LAV% was found (ρ = -0.317 for non-enhanced CT; ρ = -0.514 for contrast-enhanced CT). Difference between correlation coefficients was insignificant. CONCLUSION: Our findings suggest that contrast agent does not influence LAV% nor its correlation with TI.

Complications and downsides of the robotic total knee arthroplasty: a systematic review.

PURPOSE: The purpose of this systematic review is to describe the complications and downsides of robotic systems in total knee arthroplasty (TKA). METHODS: A comprehensive search according to the PRISMA guidelines was performed across PubMed, MEDLINE, Cochrane Central Register of Controlled Trials, Scopus, and Google Scholar from inception until December 2021. All articles of any study design directly reporting on complications and downsides of the robotic system in TKA were considered for inclusion. Risk of bias assessment was performed for all included studies using the Cochrane risk of bias and MINORS score. RESULTS: A total of 21 studies were included, consisting of 4 randomized controlled trials, 7 prospective studies and 10 retrospective studies. Complications of the robotic system were pin-hole fracture, pin-related infection, iatrogenic soft tissue and bony injury, and excessive blood loss. While, downsides were longer operative duration, higher intraoperative cost, learning curve and aborting a robotic TKA due to different reasons. Iatrogenic injuries were more common in the active robotic system and abortion of the robotic TKA was reported only with active robotic TKA. CONCLUSION: Robotic TKA is associated with certain advantages and disadvantages. Therefore, surgeons need to be familiar with the system to use it effectively. Widespread adoption of the robotic system should always be evidence-based. LEVEL OF EVIDENCE: IV.

Total knee arthroplasty improves sports activity and the patient-reported functional outcome at mid-term follow-up.

PURPOSE: The purpose of this study was to assess (1) sports participation and preference for the type of sports activity after TKA, (2) mid-term functional outcome and activity level, (3) correlation of different age groups with activity level and functional outcomes, and (4) mid-term survivorship of the prosthesis. METHODS: A retrospective review of prospectively collected data was performed. 182 patients were included who underwent primary TKA between January 2010 and December 2016. Inclusion criteria were symptomatic knee osteoarthritis, age 50-90 years, and with a minimum of 5-year follow-up after TKA. Patients with rheumatoid arthritis and revision TKA were excluded. Sports participation and sports preference, Oxford Knee Score (OKS), Tegner Activity Level, and Visual Analogue Scale (VAS) for pain were recorded pre- and postoperatively at 6 months, 1 year, 2 years, and 5 years. The patient cohort was subdivided according to age groups; activity levels, patient-reported outcomes, and improvement in knee pain were correlated with these age groups. Kaplan-Meier curves were used to investigate survivorship at a minimum of 5 years. RESULTS: The mean age of the cohort was 75.6 ± 7.2 years (range 52-89). Significant improvement was noted in sports participation (p < 0.003). After TKA, there was no change in the preference for sports and none of the patients had to discontinue their sporting activity. OKS improved significantly at all follow-up time points compared to the preoperative score (p < .0001). Patients' sports and physical activity improved significantly at 1 year compared to the preoperative activity level (p < 0.001). Although the Tegner activity level improved over time, this improvement was not significant (NS), while it was significantly higher in males than in females (p < 0.004). Significant improvement was found in the VAS for pain at all follow-up time points compared to the preoperative score (p < .0001). Survivorship was found to be 100% at a 5-year follow-up. CONCLUSION: After TKA, patients can be able to return to sporting activity or even perform better than before surgery. Maximum improvement was noted in the first post-operative year. The male and younger groups perform better than the female and older groups. Sports and physical activity do not negatively impact survivorship of the knee prosthesis at mid-term follow-up and all patients are encouraged to take up sports participation after their TKA. LEVEL OF EVIDENCE: Level 3.

Revision ACL reconstruction using quadriceps, hamstring and patellar tendon autografts leads to similar functional outcomes but hamstring graft has a higher tendency of graft failure.

PURPOSE: The purpose of this study was to evaluate the differences in the patient-reported functional outcomes, and graft failure in revision ACL reconstruction using quadriceps tendon (QT), Hamstring tendon (HT) and bone-patellar tendon-bone (BPTB) autografts. METHODS: Between 2010 and 2020, 97 patients who underwent revision ACL reconstruction (40 patients received a QT, 26 an HT and 31 a BPTB graft) met the inclusion criteria. Pre-injury and at 2-year postoperatively patients were evaluated for patient-reported functional outcomes; Lysholm knee score, Tegner activity level and VAS (visual analogue scale) for pain; and graft failure. Patient-reported outcomes and graft failure were compared between the QT, HT and BPTB groups. The patients with graft failure were not included for outcome analysis at 2-years of follow-up. RESULTS: All three revision groups with QT, HT and BPTB autograft did not differ significantly in terms of age, sex, time from injury to surgery, concomitant injuries and single-stage or double-stage procedures (n.s.). No significant difference was found in the pre-injury patient-reported outcome; Lysholm knee score, Tegner activity and VAS for pain (n.s.) between the three groups. At the 2-year follow-up functional outcomes improved in all three groups and all the patients returned to pre-injury activity level; however, no significant difference was found in functional outcomes at the 2-year follow-up between the three groups (n.s.). Graft failure occurred in 4 (10%), 5 (19%) and 3 (10%) patients of QT, HT and BPTB groups, respectively. However, the rate of failure did not differ significantly between groups. CONCLUSION: All three autografts (QT, HT and BPTB) demonstrated satisfactory patient-reported outcomes in revision ACL reconstruction. Compared with QT and BPTB grafts, HT graft showed a higher tendency for failure rates. With the increasing incidence of revision ACL reconstruction, surgeons should be aware of all the available graft options. The findings of this study will assist the surgeons in the graft selection for revision ACL reconstruction. LEVEL OF EVIDENCE: Level III.

Quadriceps tendon autograft with or without bone block have comparable clinical outcomes, complications and revision rate for ACL reconstruction: a systematic review.

PURPOSE: The purpose of this systematic review is to report complications, graft failure, fixation methods, rehabilitation protocol, clinical and patient-reported outcomes, and return to sports with the use of quadriceps tendon graft with the bone block (QT-B) and without bone block (QT-S). METHODS: According to the PRISMA guidelines a comprehensive search was performed across PubMed/MEDLINE, Scopus, EMBASE, and Cochrane Library databases from inception until April 2022. Only prospective studies using quadriceps tendon autograft with a minimum of 20 patients were considered for inclusion. The outcome measures extracted from the studies were the KT-1000, Lysholm score, Subjective and Objective IKDC, Tegner, Marx Score, complications, failures and/or revision surgery, and rate of return to sports. Cochrane risk of bias and MINORS tool were used for the risk of bias assessment of all included studies. RESULTS: A total of 13 studies were included, consisting of 5 randomized controlled trials, 6 cohort studies, 1 case-control and 1 case series. A total of 484 patients received QT-S in 6 studies of which 224 (46.2%) were males and 212 (43.8%) females with a mean age of 21.5 ± 7.5 (range 14-58). While 243 patients received QT-B in 7 studies of which 167 (68.7%) were males and 76 (31.3%) females with a mean age of 28.9 ± 4.5 (range: 18-49). The studies analyzed had a mean MINORS score of 14.6 (range, 12-19). Both QT-B and QT-S for ACL reconstruction reported satisfactory results in terms of patient-reported outcome measures. Although, a slightly higher anterior laxity was found with the QT-S than with the QT-B. CONCLUSION: Quadriceps tendon with a bone block (QT-B) or without bone block (QT-S) for ACL reconstruction is supported by current literature. Both grafts are safe and viable options for ACL reconstruction with comparable clinical outcomes, complications and revision rates. LEVEL OF EVIDENCE: Level IV. REGISTRATION: PROSPERO-CRD42022347134; https://www.crd.york.ac.uk/prospero/.

No difference in sports participation and patient-reported functional outcomes between total knee arthroplasty and unicompartmental knee arthroplasty at minimum 2-year follow-up in a matched control study.

PURPOSE: The purpose of this study was to compare (1) sports participation and type of sports activity between TKA and UKA patients; (2) functional outcome and activity level between TKA and UKA; and (3) survivorship of the prosthesis in both the groups. METHODS: Prospectively collected data were obtained from an arthroplasty database to identify patients who underwent primary TKA and UKA. Both the cohorts of TKA and UKA were matched, controlling for age, sex, BMI and preoperative patient-reported outcomes, which include Oxford Knee Score (OKS), Tegner activity level, and visual analog scale (VAS) for pain score. After matching the two groups, 287 TKA and 69 UKA cases were available to be included in the study. Patients were evaluated pre- and postoperatively at 2 years for sports participation and sports preference, patient-reported outcomes, activity levels, and improvement in knee pain. RESULTS: The mean age of the TKA and UKA groups were 75.7 ± 8.1 and 74.2 ± 8.8, respectively. There was no significant difference between the two groups concerning the demographic variables. Significant improvement was noted in the weekly sports participation at the final follow-up compared to preoperative sports participation in both the TKA and UKA groups (p < 0.05). All patients were able to return to their desired sporting activity. No significant difference was noted between the two groups in sports participation preoperatively and postoperatively (p > 0.05). OKS, Tegner activity level and VAS for pain demonstrated a significant improvement from preoperative to 2 years postoperatively (p < 0.05). However, preoperative and postoperative patient-reported outcomes did not differ significantly between the TKA and UKA groups (p > 0.05). No case of revision surgery was found at a 2-year follow-up in both groups. CONCLUSION: Traditionally, in isolated medial compartment osteoarthritis, UKA has been considered to be the procedure with better functional outcomes, but the current study demonstrates that when confounding factors are controlled, both TKA and UKA are effective, and offer similar functional outcomes and result in similar improvement in sports participation. These findings will be helpful to counsel the patients to choose the best suitable operative procedure between UKA and TKA. LEVEL OF EVIDENCE: Level 3.

Multiple revision anterior cruciate ligament reconstruction: not the best but still good.

PURPOSE: Given the paucity of literature on the re-revision of ACL, the current study was undertaken. The purpose of this systematic review was to synthesise and qualitatively assess the currently available evidence in the literature regarding the re-revision of ACL reconstruction (rrACLR). METHODS: A systematic review was conducted based on the PRISMA guidelines. The following search terms were used in the title, abstract and keywords fields: "ACL" or "anterior cruciate ligament" AND "revision" or "multiple" or "repeat". The outcome data extracted from the studies were the Lysholm score, Subjective IKDC, Marx Score, Tegner, Marx Score, KOOS score, radiological changes and the rate of return to sports. Complications, failures and/or revision surgery were also analysed. RESULTS: The cohort consisted of 295 patients [191 (64.7%) men and 104 (35.3%) women] with a mean age of 29.9 ± 2.8 years (range 14-58 years) from 10 studies. The mean postoperative follow-up (reported in all studies except one) was 66.9 ± 44.7 months (range 13-230.4 months). Associated injuries were 103 (34.9%) medial meniscus tears, 57 (19.3%) lateral meniscus tears, 14 (4.7%) combined medial plus lateral meniscus tears, 11 (3.7%) meniscal tears (not specified), 252 (85.4%) cartilage lesions, 6 (2.0%) medial collateral ligament injury and 2 (0.7%) lateral collateral ligament injuries. In 47 (15.9%) patients an extra-articular plasty was performed for the anterolateral ligament. In all studies that reported pre- and post-operative IKDC (subjective and objective) and Lysholm score, there was a significant improvement compared to the pre-operative value (p < 0.05). At the final follow-up, laxity measured with KT-1000 was found to be 2.2 ± 0.6 mm. 31 (10.5%) out of 295 patients returned to their pre-injury activity level. A total of 19 (6.4%) re-ruptures were found, while only 4 (1.4%) complications (all minors) were reported, out of which 2 (0.7%) were superficial infections, 1 (0.3%) cyclops lesion and 1 (0.3%) flexion loss. CONCLUSION: Multiple revisions of anterior cruciate ligament reconstruction allow acceptable clinical results and a good degree of knee stability with a low rate of subsequent new re-ruptures but the possibility of regaining pre-injury sports activity is poor; whenever possible, it is preferred to revise the ligament in one stage. This surgery remains a challenge for orthopaedic surgeons and many doubts persist regarding the ideal grafts, additional extra-articular procedures and techniques to use. LEVEL OF EVIDENCE: IV. STUDY REGISTRATION: PROSPERO-CRD42022352164 ( https://www.crd.york.ac.uk/prospero/ ).

In elite athletes with meniscal injuries, always repair the lateral, think about the medial! A systematic review.

PURPOSE: This study aimed to evaluate and compare the time required to return to sports (RTS) after surgery, the rate of revision surgery and the time required for RTS after revision surgery in elite athletes undergoing meniscal repair or partial meniscectomy, particularly analysing the difference between medial and lateral menisci. It was hypothesised that both procedures would entail similar, high rates of RTS, with the lateral meniscus exhibiting higher potential healing postprocedure compared to the medial meniscus. METHODS: A systematic review was conducted based on the PRISMA guidelines. Quality assessment of the systematic review was performed using the AMSTAR-2 checklist. The following search terms were browsed in the title, abstract and keyword fields: 'meniscus' or 'meniscal' AND 'tear,' 'injury' or 'lesion' AND 'professional,' 'elite' or 'high-level' AND 'athletes,' 'sports,' 'sportsman,' 'soccer,' 'basketball,' 'football' or 'handball'. The resulting measures extracted from the studies were the rate of RTS, level of RTS, complications, revision surgery and subsequent RTS, Tegner, International Knee Documentation Committee (IKDC) and Visual Analogue Scale (VAS). RESULTS: In this study, the cohort consisted of 421 patients [415 (98.6%) men and 6 (1.4%) women] with a mean age of 23.0 ± 3.0 years. All patients were elite athletes in wrestling, baseball, soccer, rugby or handball. While 327 (77.7%) patients received partial meniscectomy at a mean age of 23.3 ± 2.6 years, 94 (22.3%) patients received meniscal repair at a mean age of 22.1 ± 4.0 years. After partial meniscectomy, 277 patients (84.7%) returned to their competitive sports activity and 256 (78.3%) returned to their pre-injury activity levels. A total of 12 (3.7%) patients required revision surgery because of persistent pain [5 (1.5%) patients], chondrolysis [2 (0.7%) patients] or both chondrolysis and lateral instability [5 (1.5%) patients]. Ten (83.3%) of the twelve patients had involvement of the lateral meniscus, whereas the location of injury was not specified in the remaining two patients. After revision surgery, all patients (100%) resumed sports activity. However, after meniscal repair, 80 (85.1%) athletes returned to their competitive sports activity and 71 (75.5%) returned to their pre-injury activity levels. A total of 16 (17.0%) patients required partial meniscectomy in cases of persistent pain or suture failure. Of these, 4 (25%) patients involved lateral and medial menisci each and 8 (50%) patients were not specified. After revision surgery, more than 80.0% of the patients (13) resumed sports activity. CONCLUSIONS: In elite athletes with isolated meniscal injury, partial meniscectomy and meniscal suture exhibited similar rates of RTS and return to pre-injury levels. Nonetheless, athletes required more time for RTS after meniscal repair and exhibited an increased rate of revision surgery associated with a reduced rate of RTS after the subsequent surgery. For lateral meniscus tears, meniscectomy was associated with a high rate of revision surgery and risk of chondrolysis, whereas partial medial meniscectomy allowed for rapid RTS but with the potential risk of developing knee osteoarthritis over the years. The findings of this systematic review suggested a suture on the lateral meniscus in elite athletes because of the high healing potential after the procedure, the reduced risk of developing chondrolysis and the high risk of revision surgery after partial meniscectomy. Furthermore, it is important to evaluate several factors while dealing with the medial meniscus. If rapid RTS activity is needed, a hyperselective meniscectomy is recommended; otherwise, a meniscal suture is recommended to avoid accelerated osteoarthritis. LEVEL OF EVIDENCE: Level IV. STUDY REGISTRATION: PROSPERO-CRD42022351979 ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=351979 ).

Quadriceps autograft is a viable graft choice for arthroscopic ACL reconstruction in patients over 50 years of age.

PURPOSE: The purpose of this study was to evaluate the patient-reported outcomes, graft failure, quadriceps rupture and sports preference after arthroscopic ACL reconstruction in patients older than 50 years who underwent arthroscopic ACL reconstruction with a quadriceps tendon (QT) autograft. METHODS: Between 2010 and 2020, prospectively collected data were obtained from an institutional database. Patients older than 50 years with primary arthroscopic ACL reconstruction and a minimum of 2 years of follow-up were included. Patients undergoing a revision ACL reconstruction or undergoing a primary ACL reconstruction using a graft other than a QT autograft, and patients with a contralateral knee injury or osteoarthritis (Ahlbäck stage 2 or higher) were excluded. A minimally invasive technique was used for QT autograft harvesting. Patients were evaluated for pre-injury and 2-year follow-up Lysholm knee score, Tegner activity level, Visual Analog Scale (VAS) for pain, graft failure, quadriceps tendon rupture, and return to sport. RESULTS: A total of 57 patients were included in the study. The mean age of the cohort was 54.9 ± 5.2 (range 50-75). Of the 57 reconstructions, 16 (28%) were isolated ACL reconstructions, while 41 (72%) were complex reconstructions (concomitant meniscus, cartilage and/or collateral ligament injuries). At the 2-year follow-up Lysholm knee score, Tegner activity level and VAS for pain improved to pre-injury level and no significant difference was noted between pre-injury and 2-year follow-up functional scores (n.s.). No case of graft failure or quadriceps tendon rupture was reported. No significant difference was noted in the pre-injury and postoperative sports preference (n.s.) and all patients return to their desired sports activity. CONCLUSION: Arthroscopic ACL reconstruction by using QT autograft in highly active older patients provides satisfactory patient-reported functional outcomes and allows recovery of the pre-injury level of activity. QT autograft is a good graft option in patients older than 50 years. LEVEL OF EVIDENCE: Level IV.

The "Bankart knee": high-grade impression fractures of the posterolateral tibial plateau lead to increased translational and anterolateral rotational instability of the ACL-deficient knee.

PURPOSE: The aim of this biomechanical cadaver study was to evaluate the effects of high-grade posterolateral tibia plateau fractures on the kinematics of anterior cruciate ligament (ACL)-deficient joints; it was hypothesized that, owing to the loss of the integrity of the osseous support of the posterior horn of the lateral meniscus (PHLM), these fractures would influence the biomechanical function of the lateral meniscus (LM) and consequently lead to an increase in anterior translational and anterolateral rotational (ALR) instability. METHODS: Eight fresh-frozen cadaveric knees were tested using a six-degree-of-freedom robotic setup (KR 125, KUKA Robotics, Germany) with an attached optical tracking system (Optotrack Certus Motion Capture, Northern Digital, Canada). After the passive path from 0 to 90° was established, a simulated Lachman test and pivot-shift test as well as external rotation (ER) and internal rotation (IR) were applied at 0°, 30°, 60° and 90° of flexion under constant 200 N axial loading. All of the parameters were initially tested in the intact and ACL-deficient states, followed by two different types of posterolateral impression fractures. The dislocation height was 10 mm, and the width was 15 mm in both groups. The intraarticular depth of the fracture corresponded to half of the width of the posterior horn of the lateral meniscus in the first group (Bankart 1) and 100% of the meniscus width in the second group (Bankart 2). RESULTS: There was a significant decrease in knee stability after both types of posterolateral tibial plateau fractures in the ACL-deficient specimens, with increased anterior translation in the simulated Lachman test at 0° and 30° of knee flexion (p = 0.012). The same effect was seen with regard to the simulated pivot-shift test and IR of the tibia (p = 0.0002). In the ER and posterior drawer tests, ACL deficiency and concomitant fractures did not influence knee kinematics (n.s.). CONCLUSION: This study demonstrates that high-grade impression fractures of the posterolateral aspect of the tibial plateau increase the instability of ACL-deficient knees and result in an increase in translational and anterolateral rotational instability.

No difference in patient reported outcomes, laxity, and failure rate after revision ACL reconstruction with quadriceps tendon compared to hamstring tendon graft: a systematic review and meta-analysis.

PURPOSE: The purpose of this study was to synthesize and quantitatively assess the outcomes of ACL Revision using a quadriceps tendon (QT) graft and to compare them with those of ACL Revisions performed with hamstring tendons (HT) graft. METHODS: A comprehensive search based on the PRISMA protocol was performed across PubMed, Scopus, Embase, and Cochrane Library from inception until February 2022. Clinical studies reporting the outcomes of ACL Revision with QT autograft were included. Subjective and Objective IKDC, Tegner activity level, Lysholm knee score, KOOS score, VAS for pain, knee laxity (KT-1000/2000 arthrometer, Lachman test, and pivot-shift test), and graft failure were assessed. A systematic review and meta-analysis were performed and a quality assessment of the included studies was carried out with the MINORS score. RESULTS: Seven studies met the selection criteria and were included in the systematic review for the qualitative synthesis of data. A pooled mean of all the variables was provided for the 7 studies, while 3 studies included a control group of ACL Revision with HT and were included in a meta-analysis. A total of 420 participants with a mean age of 28.9 ± 10.5 years and a mean postoperative follow-up of 39.3 ± 16.4 months were assessed. Of these, 277 patients underwent ACL Revision with QT and 143 patients underwent ACL Revision with HT. In the QT group, average graft failure was 9.8% compared to 17.4% in the HT group. KOOS Sport and pivot-shift test showed better postoperative outcomes in QT than HT, although it was not statistically significant (p = 0.052). CONCLUSION: The QT autograft was associated with an improved trend of rotatory laxity, PROMs and failure rate compared to HT autograft after revision ACL reconstruction. The QT autograft for revision ACL reconstruction is supported by the current literature. It is a viable graft that should be considered for both primary and revision ACL reconstruction. LEVEL OF EVIDENCE: Level IV.

Optical Measurement of Ligament Strain: Opportunities and Limitations for Intraoperative Application.

A feasible and precise method to measure ligament strain during surgical interventions could significantly enhance the quality of ligament reconstructions. However, all existing scientific approaches to measure in vivo ligament strain possess at least one significant disadvantage, such as the impairment of the anatomical structure. Seeking a more advantageous method, this paper proposes defining medical and technical requirements for a non-destructive, optical measurement technique. Furthermore, we offer a comprehensive review of current optical endoscopic techniques which could potentially be suitable for in vivo ligament strain measurement, along with the most suitable optical measurement techniques. The most promising options are rated based on the defined explicit and implicit requirements. Three methods were identified as promising candidates for a precise optical measurement of the alteration of a ligaments strain: confocal chromatic imaging, shearography, and digital image correlation.

Contralateral ACL tears strongly contribute to high rates of secondary ACL injuries in professional ski racers.

PURPOSE: To analyse the effects of graft selection, sex, injury complexity and time to return to competition on the odds to suffer secondary ACL injury (either re-rupture or contralateral ACL tear) in professional alpine skiers. METHODS: The database of a specialised joint surgery clinic was screened for professional alpine skiers who had participated in competitions at the FIS race, European Cup and World Cup level prior to having to undergo a primary ACL reconstruction, and who had returned to the same competitional level at least one year prior to the end of the observation period. The rates of secondary ACL injuries were statistically compared between athletes with hamstring and quadriceps tendon autografts, men and women, simple and complex (involvement of menisci or cartilage) primary ACL injuries, and between early (≤ 300 days after primary reconstruction) and late (> 300 days) returners to competition. RESULTS: Fourteen out of the 30 athletes included (46.7%) suffered secondary ACL injuries on average 29.4 ± 22.5 months after primary reconstruction. The secondary injuries comprised five re-ruptures (16.7%) and nine contralateral ACL tears (30.0%). The odds to suffer contralateral ACL tears were non-significantly higher in patients with hamstring tendon autografts (OR 5.69, n.s.) and in those whose primary injuries were classified as simple ACL tears (OR 5.31, n.s.). None of the factors assessed was associated with the odds of graft failure. CONCLUSION: The odds of ACL-injured professional alpine ski racers to suffer secondary ACL tears are nearly 50%, with subsequent contralateral ACL injuries being more common than graft failures. While statistical significance could not be established due to a lack of power, greater odds of contralateral ACL tears were observed in athletes with hamstring tendon grafts as well as those with simple primary ACL injuries. No factors potentially predisposing athletes for graft failure could be identified. LEVEL OF EVIDENCE: III.

The evaluation of Rolimeter, KLT, KiRA and KT-1000 arthrometer in healthy individuals shows acceptable intra-rater but poor inter-rater reliability in the measurement of anterior tibial knee translation.

PURPOSE: To assess measurement equivalence, inter- and intra-rater reliability, standard error of measurements (SEM) and false positive measurements (FPM) of four different knee arthrometers (KLT,Karl Storz; KiRA, I + ; KT-1000 MEDmetric Corp; Rolimeter, Aircast) in healthy patients. METHODS: Four different investigators (two advanced (AR) and two beginners (BR)) examined 12 participants with healthy knees at two time points with regards to anterior tibial translation (ATT) and side-to-side difference (SSD). Test equivalence was assessed using the TOST (two-one-sided t test) procedure with ± 1 mm equivalence boundaries. Intraclass correlation coefficients (ICCs) were calculated using two-way mixed effects models. Furthermore, false positive-(SSD > 3 mm) and SEMs were assessed. RESULTS: A total of 2304 Lachman Tests were performed. Between-rater SSDs were equivalent between AR and BR raters for the Rolimeter only. Inter-rater ICC values (SSD, ATT) were graded as "poor" to "moderate" for all devices. Equivalent test-retest results were observed for all raters using the Rolimeter, KLT and KT-1000, whereas measurement consistency with KiRA was given in the advanced examiners group only. Intra-rater ICC values (Range: SSD, ATT) were graded as "poor" to "moderate" for SSD values and "moderate" to "good" for ATT. SEMs were lowest for the Rolimeter and highest for KiRA. FPM were never obtained with the Rolimeter (0%), twice (2.1%) with the KT-1000, three times (3.1%) with the KLT and 33 times (34.4%) using KiRA. CONCLUSION: There is acceptable intra-rater but poor inter-rater reliability with all tested arthrometers. Measures of knee laxity are comparable between Rolimeter, KLT and KT-1000 but higher for KiRA. Clinically, the present study shows that repeated arthrometry measurements should always be performed by the same investigators.

The superficial medial collateral ligament is the major restraint to anteromedial instability of the knee.

PURPOSE: The purpose of the present study was to determine how the medial structures and ACL contribute to restraining anteromedial instability of the knee. METHODS: Twenty-eight paired, fresh-frozen human cadaveric knees were tested in a six-degree of freedom robotic setup. After sequentially cutting the dMCL, sMCL, POL and ACL in four different cutting orders, the following simulated clinical laxity tests were applied at 0°, 30°, 60° and 90° of knee flexion: 4 Nm external tibial rotation (ER), 4 Nm internal tibial rotation (IR), 8 Nm valgus rotation (VR) and anteromedial rotation (AMR)-combined 89 N anterior tibial translation and 4 Nm ER. Knee kinematics were recorded in the intact state and after each cut using an optical tracking system. Differences in medial compartment translation (AMT) and tibial rotation (AMR, ER, IR, VR) from the intact state were then analyzed. RESULTS: The sMCL was the most important restraint to AMR, ER and VR at all flexion angles. Release of the proximal tibial attachment of the sMCL caused no significant increase in laxity if the distal sMCL attachment remained intact. The dMCL was a minor restraint to AMT and ER. The POL controlled IR and was a minor restraint to AMT and ER near extension. The ACL contributed with the sMCL in restraining AMT and was a secondary restraint to ER and VR in the MCL deficient knee. CONCLUSION: The sMCL appears to be the most important restraint to anteromedial instability; the dMCL and POL play more minor roles. Based on the present data a new classification of anteromedial instability is proposed, which may support clinical examination and treatment decision. In higher grades of anteromedial instability an injury to the sMCL should be suspected and addressed if treated surgically.

Sonographic evaluation of lateral meniscal extrusion: implementation and validation.

INTRODUCTION: Meniscal extrusion (ME) is an important indicator of and prognostic factor for various knee pathologies. To date, no standardized protocol for the ultrasound-based examination of lateral ME exists. The purpose of the present study was to test the reliability and validity of lateral ME measurements using a standardized ultrasound-based examination protocol. MATERIALS AND METHODS: A group consisting of 11 healthy volunteers (Group I, male and female, 18-45 years) as well as a group of 10 consecutive patients who had undergone all-inside lateral meniscal radial tear repair were included (Group II, male and female, 23-43 years). Lateral ME, the main outcome parameter, was measured by ultrasound (US; both groups) and magnetic resonance imaging (MRI; Group II only). Both knees of all subjects were examined in an unloaded state and under axial compression of the knee (50% of body weight). Repeated measurements obtained in Group I by 2 observers were used for reliability testing, and the validity of US was assessed through comparison with MRI data (Group II). RESULTS: A total of 66 US images of Group I, obtained by each observer, were analyzed for reliability testing. Forty US and MR images of Group II were assessed for validation. Results showed good interrater (ICC = 0.904) and excellent intrarater (ICC = 0.942) reliability of US-based measurements of lateral ME. Agreement with MRI results was poor (ICC = 0.439), with US systematically overestimating results by 1.1 mm on average. CONCLUSIONS: Ultrasound is a reliable, quick and cost-effective technique for lateral ME measurement, but results are not readily comparable with MRI. TRIAL REGISTRATION: The study was registered in the European Union Clinical Trials Register (EudraCT-Number: 2017-005037-24).