Aims

MRI has been suggested as an objective method of assessing anterior crucate ligament (ACL) graft “ligamentization” after reconstruction. It has been proposed that the MRI appearances could be used as an indicator of graft maturity and used as part of a return-to-sport assessment. The aim of this study was to evaluate the correlation between MRI graft signal and postoperative functional scores, anterior knee laxity, and patient age at operation.

Aims. The effects of remnant preservation on the anterior cruciate ligament (ACL) and its relationship with the tendon graft remain unclear. We hypothesized that the co-culture of remnant cells and bone marrow stromal cells (BMSCs) decreases apoptosis and enhances the activity of the hamstring tendons and tenocytes, thus aiding ACL reconstruction. Methods. The ACL remnant, bone marrow, and hamstring tendons were surgically harvested from rabbits. The apoptosis rate, cell proliferation, and expression of types I and III collagen, transforming growth factor-β (TGF-β), vascular endothelial growth factor (VEGF), and tenogenic genes (scleraxis (SCX), tenascin C (TNC), and tenomodulin (TNMD)) of the hamstring tendons were compared between the co-culture medium (ACL remnant cells (ACLRCs) and BMSCs co-culture) and control medium (BMSCs-only culture). We also evaluated the apoptosis, cell proliferation, migration, and gene expression of hamstring tenocytes with exposure to co-culture and control media. Results. Compared to BMSCs-only culture medium, the co-culture medium showed substantially decreased early and late apoptosis rates, attenuation of intrinsic and extrinsic apoptotic pathways, and enhanced proliferation of the hamstring tendons and tenocytes. In addition, the expression of collagen synthesis, TGF-β, VEGF, and tenogenic genes in the hamstring tendons and tenocytes significantly increased in the co-culture medium compared to that in the control medium. Conclusion. In the presence of ACLRCs and BMSCs, the hamstring tendons and tenocytes significantly attenuated apoptosis and enhanced the expression of collagen synthesis, TGF-β, VEGF, and tenogenic genes. This in vitro study suggests that the ACLRCs mixed with BMSCs could aid regeneration of the hamstring tendon graft during ACL reconstruction. Cite this article: Bone Joint Res 2023;12(1):9–21

Aims. The aim of this study was to report the pooled prevalence of post-traumatic osteoarthritis (PTOA) and examine whether the risk of developing PTOA after anterior cruciate ligament (ACL) injury has decreased in recent decades. Methods. The PubMed and Web of Science databases were searched from 1 January 1980 to 11 May 2022. Patient series, observational studies, and clinical trials having reported the prevalence of radiologically confirmed PTOA after ACL injury, with at least a ten-year follow-up, were included. All studies were analyzed simultaneously, and separate analyses of the operative and nonoperative knees were performed. The prevalence of PTOA was calculated separately for each study, and pooled prevalence was reported with 95% confidence intervals (CIs) using either a fixed or random effects model. To examine the effect of the year of injury on the prevalence, a logit transformed meta-regression analysis was used with a maximum-likelihood estimator. Results from meta-regression analyses were reported with the unstandardized coefficient (β). Results. The pooled prevalence of PTOA was 37.9% (95% CI 32.1 to 44) for operatively treated ACL injuries with a median follow-up of 14.6 years (interquartile range (IQR) 10.6 to 16.7). For nonoperatively treated ACL injuries, the prevalence was 40.5% (95% CI 28.9 to 53.3), with a median of follow-up of 15 years (IQR 11.7 to 20.0). The association between the year of operation and the prevalence of PTOA was weak and imprecise and not related to the choice of treatment (operative β -0.038 (95% CI -0.076 to 0.000) and nonoperative β -0.011 (95% CI -0.101 to 0.079)). Conclusion. The initial injury, irrespective of management, has, by the balance of probability, resulted in PTOA within 20 years. In addition, the prevalence of PTOA has only slightly decreased during past decades. Therefore, further research is warranted to develop strategies to prevent the development of PTOA after ACL injuries. Cite this article: Bone Joint J 2023;105-B(11):1140–1148

Aims. The aim of this study was to estimate the incremental use of resources, costs, and quality of life outcomes associated with surgical reconstruction compared to rehabilitation for long-standing anterior cruciate ligament (ACL) injury in the NHS, and to estimate its cost-effectiveness. Methods. A total of 316 patients were recruited and randomly assigned to either surgical reconstruction or rehabilitation (physiotherapy but with subsequent reconstruction permitted if instability persisted after treatment). Healthcare resource use and health-related quality of life data (EuroQol five-dimension five-level health questionnaire) were collected in the trial at six, 12, and 18 months using self-reported questionnaires and medical records. Using intention-to-treat analysis, differences in costs, and quality-adjusted life years (QALYs) between treatment arms were estimated adjusting for baseline differences and following multiple imputation of missing data. The incremental cost-effectiveness ratio (ICER) was estimated as the difference in costs divided by the difference in QALYs between reconstruction and rehabilitation. Results. At 18 months, patients in the surgical reconstruction arm reported higher QALYs (0.052 (95% confidence interval (CI) -0.012 to 0.117); p = 0.177) and higher NHS costs (£1,017 (95% CI 557 to 1,476); p < 0.001) compared to rehabilitation. This resulted in an ICER of £19,346 per QALY with the probability of surgical reconstruction being cost-effective of 51% and 72% at a willingness-to-pay threshold of £20,000 and £30,000 per QALY, respectively. Conclusion. Surgical reconstruction as a management strategy for patients with long-standing ACL injury is more effective, but more expensive, at 18 months compared to rehabilitation management. In the UK setting, surgical reconstruction is cost-effective. Cite this article: Bone Joint J 2024;106-B(1):38–45

Aims. The anterior cruciate ligament (ACL) is known to have a poor wound healing capacity, whereas other ligaments outside of the knee joint capsule such as the medial collateral ligament (MCL) apparently heal more easily. Plasmin has been identified as a major component in the synovial fluid that varies among patients. The aim of this study was to test whether plasmin, a component of synovial fluid, could be a main factor responsible for the poor wound healing capacity of the ACL. Methods. The effects of increasing concentrations of plasmin (0, 0.1, 1, 10, and 50 µg/ml) onto the wound closing speed (WCS) of primary ACL-derived ligamentocytes (ACL-LCs) were tested using wound scratch assay and time-lapse phase-contrast microscopy. Additionally, relative expression changes (quantitative PCR (qPCR)) of major LC-relevant genes and catabolic genes were investigated. The positive controls were 10% fetal calf serum (FCS) and platelet-derived growth factor (PDGF). Results. WCS did not differ significantly among no plasmin versus each of the tested concentrations (six donors). The positive controls with PDGF and with FCS differed significantly from the negative controls. However, we found a trend demonstrating that higher plasmin concentrations up-regulate the expression of matrix metalloproteinase 13 (MMP13), 3 (MMP3), and tenomodulin (TNMD). Conclusion. The clinical relevance of this study is the possibility that it is not solely the plasmin, but also additional factors in the synovial fluid of the knee, that may be responsible for the poor healing capacity of the ACL. Cite this article: Bone Joint Res 2020;9(9):543–553

Aims. Post-traumatic osteoarthritis (PTOA) is a subset of osteoarthritis (OA). The gut microbiome is shown to be involved in OA. However, the effect of exercise on gut microbiome in PTOA remains elusive. Methods. A total of 18 eight-week Sprague-Dawley rats were assigned into three groups: Sham/sedentary (Sham/Sed), PTOA/sedentary (PTOA/Sed), and PTOA/treadmill-walking (PTOA/TW). PTOA model was induced by transection of the anterior cruciate ligament (ACLT) and the destabilization of the medial meniscus (DMM). Treadmill-walking (15 m/min, 30 min/d, five days/week for eight weeks) was employed in the PTOA/TW group. The response of cartilage, subchondral bone, serology, and gut microbiome and their correlations were assessed. Results. Eight-week treadmill-walking was effective at maintaining the integrity of cartilage-subchondral bone unit and reducing the elevated systematic inflammation factors and microbiome-derived metabolites. Furthermore, 16S ribosomal ribonucleic acid (rRNA) sequencing showed disease-relevant microbial shifts in PTOA animals, characterized by the decreased abundance of phylum TM7 and the increase of phylum Fusobacteria. At the genus level, the abundance of Lactobacillus, Turicibacter, Adlercreutzia, and Cetobacterium were increased in the PTOA animals, while the increase of Adlercreutzia and Cetobacterium was weakened as a response to exercise. The correlation analysis showed that genus Lactobacillus and Adlercreutzia were correlated to the structural OA phenotypes, while phylum Fusobacteria and genus Cetobacterium may contribute to the effects of exercise on the diminishment of serological inflammatory factors. Conclusion. Exercise is effective at maintaining the integrity of cartilage-subchondral bone unit, and the exercise-induced modification of disease-relevant microbial shifts is potentially involved in the mechanisms of exercise-induced amelioration of PTOA. Cite this article: Bone Joint Res 2022;11(4):214–225

The Anterior Cruciate Ligament (ACL) plays a vital role in maintaining function and stability in the knee. Over the last several decades, much research has been focused on elucidating the anatomy, structural properties, biomechanics, pathology, and optimal treatments for the ACL. Through careful and objective study, the ACL can be understood to be a dynamic structure, rich in neurovascular supply. Although it is referred to as one ligament, it is comprised of two dis-tinct bundles which function synergistically to facilitate normal knee kinematics. The bony morphology of the knee defines normal knee kinematics, as well as the nature of the soft-tissue structures about the knee. Characterized by individual uniqueness, bony morphology varies from patient to patient. The ACL, which is a reflection of each patient's unique bony morphol-ogy, is inherently subject to both anatomic and morphologic variation as well. Furthermore, the ACL is subject to physiologic aging, which can affect the anatomic and structural properties of the ligament over time. A successful anatomic ACL Reconstruction, which may be considered the functional restoration of the ACL to its native dimensions, collagen orientation, and inser-tion sites according to individual anatomy, considers all these principles. It is vital to respect the nature we observe, rather than to “create” nature to fit a one-size-fits-all surgery. Double bundle ACL Reconstruction may therefore be thought of more as a concept rather than a specific technique, one that respects the individual unique anatomy of each patient to provide a truly indi-vidualized, anatomic, and value-based ACL Reconstruction

Aims. The aim of this study was to screen the entire genome for genetic markers associated with risk for anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injury. Methods. Genome-wide association (GWA) analyses were performed using data from the Kaiser Permanente Research Board (KPRB) and the UK Biobank. ACL and PCL injury cases were identified based on electronic health records from KPRB and the UK Biobank. GWA analyses from both cohorts were tested for ACL and PCL injury using a logistic regression model adjusting for sex, height, weight, age at enrolment, and race/ethnicity using allele counts for single nucleotide polymorphisms (SNPs). The data from the two GWA studies were combined in a meta-analysis. Candidate genes previously reported to show an association with ACL injury in athletes were also tested for association from the meta-analysis data from the KPRB and the UK Biobank GWA studies. Results. There was a total of 2,214 cases of ACL and PCL injury and 519,869 controls within the two cohorts, with three loci demonstrating a genome-wide significant association in the meta-analysis: INHBA, AEBP2, and LOC101927869. Of the eight candidate genes previously studied in the literature, six were present in the current dataset, and only COL3A1 (rs1800255) showed a significant association (p = 0.006). Conclusion. Genetic markers in three novel loci in this study and one previously-studied candidate gene were identified as potential risk factors for ACL and PCL injury and deserve further validation and investigation of molecular mechanisms. Cite this article: Bone Jt Open 2021;2(6):414–421

The anterior cruciate ligament (ACL) is the connective tissue located at the end of long bones providing stability to the knee joint. After tear or rupture clinical reconstruction of the tissue remains a challenge due to the particular mechanical properties required for proper functioning of the tissue. The outstanding mechanical properties of the ACL are characterized by a viscoelastic behavior responsible of the dissipation of the loads that are transmitted to the bone. These mechanical properties are the result of a very specialized graded extracellular matrix that transitions smoothly between the heterotypic cells, stiffness and composition of the ACL and the adjacent bone. Thus, mimicking the zonal biochemical composition, cellular phenotype and organization are key to reset the proper functioning of the ACL. We have previously shown how the biochemical composition presented to cells in electrospun scaffolds results in haptokinesis, reverting contact-guidance effects. [1]. Here, we demonstrate that contact guidance can also be disrupted by structural parameters in aligned wavy scaffolds. The presentation of a wavy fiber arrangement affected the cell organization and the deposition of a specific ECM characteristic of fibrocartilage. Cells cultured in wavy scaffolds grew in aggregates, deposited an abundant ECM rich in fibronectin and collagen II, and expressed higher amounts of collagen II, X and tenomodulin as compared to aligned scaffolds. In-vivo implantation in rabbits of triphasic scaffolds accounting for aligned-wavy-aligned zones showed a high cellular infiltration and the formation of an oriented ECM, as compared to traditional aligned scaffolds. [2]

Aims. The objectives of this study were to assess the effect of anterior cruciate ligament (ACL) resection on flexion-extension gaps, mediolateral soft tissue laxity, maximum knee extension, and limb alignment during primary total knee arthroplasty (TKA). Methods. This prospective study included 140 patients with symptomatic knee osteoarthritis undergoing primary robotic-arm assisted TKA. All operative procedures were performed by a single surgeon using a standard medial parapatellar approach. Optical motion capture technology with fixed femoral and tibial registration pins was used to assess study outcomes pre- and post-ACL resection with knee extension and 90° knee flexion. This study included 76 males (54.3%) and 64 females (45.7%) with a mean age of 64.1 years (SD 6.8) at time of surgery. Mean preoperative hip-knee-ankle deformity was 6.1° varus (SD 4.6° varus). Results. ACL resection increased the mean extension gap significantly more than the flexion gap in the medial (mean 1.2 mm (SD 1.0) versus mean 0.2 mm (SD 0.7) respectively; p < 0.001) and lateral (mean 1.1 mm (SD 0.9) versus mean 0.2 mm (SD 0.6) respectively; p < 0.001) compartments. The mean gap differences following ACL resection did not create any significant mediolateral soft tissue laxity in extension (gap difference: mean 0.1 mm (SD 2.4); p = 0.89) or flexion (gap difference: mean 0.2 mm (SD 3.1); p = 0.40). ACL resection did not significantly affect maximum knee extension (change in maximum knee extension = mean 0.2° (SD 0.7°); p = 0.23) or fixed flexion deformity (mean 4.2° (SD 3.2°) pre-ACL release versus mean 3.9° (SD 3.7°) post-ACL release; p = 0.61). ACL resection did not significantly affect overall limb alignment (change in alignment = mean 0.2° valgus (SD 1.0° valgus; p = 0.11). Conclusion. ACL resection creates flexion-extension mismatch by increasing the extension gap more than the flexion gap. However, gap differences following ACL resection do not create any mediolateral soft tissue laxity in extension or flexion. ACL resection does not affect maximum knee extension or overall limb alignment. Cite this article: Bone Joint J 2020;102-B(4):442–448

External validation of machine learning predictive models is achieved through evaluation of model performance on different groups of patients than were used for algorithm development. This important step is uncommonly performed, inhibiting clinical translation of newly developed models. Recently, machine learning was used to develop a tool that can quantify revision risk for a patient undergoing primary anterior cruciate ligament (ACL) reconstruction (https://swastvedt.shinyapps.io/calculator_rev/). The source of data included nearly 25,000 patients with primary ACL reconstruction recorded in the Norwegian Knee Ligament Register (NKLR). The result was a well-calibrated tool capable of predicting revision risk one, two, and five years after primary ACL reconstruction with moderate accuracy. The purpose of this study was to determine the external validity of the NKLR model by assessing algorithm performance when applied to patients from the Danish Knee Ligament Registry (DKLR). The primary outcome measure of the NKLR model was probability of revision ACL reconstruction within 1, 2, and/or 5 years. For the index study, 24 total predictor variables in the NKLR were included and the models eliminated variables which did not significantly improve prediction ability - without sacrificing accuracy. The result was a well calibrated algorithm developed using the Cox Lasso model that only required five variables (out of the original 24) for outcome prediction. For this external validation study, all DKLR patients with complete data for the five variables required for NKLR prediction were included. The five variables were: graft choice, femur fixation device, Knee Injury and Osteoarthritis Outcome Score (KOOS) Quality of Life subscale score at surgery, years from injury to surgery, and age at surgery. Predicted revision probabilities were calculated for all DKLR patients. The model performance was assessed using the same metrics as the NKLR study: concordance and calibration. In total, 10,922 DKLR patients were included for analysis. Average follow-up time or time-to-revision was 8.4 (±4.3) years and overall revision rate was 6.9%. Surgical technique trends (i.e., graft choice and fixation devices) and injury characteristics (i.e., concomitant meniscus and cartilage pathology) were dissimilar between registries. The model produced similar concordance when applied to the DKLR population compared to the original NKLR test data (DKLR: 0.68; NKLR: 0.68-0.69). Calibration was poorer for the DKLR population at one and five years post primary surgery but similar to the NKLR at two years. The NKLR machine learning algorithm demonstrated similar performance when applied to patients from the DKLR, suggesting that it is valid for application outside of the initial patient population. This represents the first machine learning model for predicting revision ACL reconstruction that has been externally validated. Clinicians can use this in-clinic calculator to estimate revision risk at a patient specific level when discussing outcome expectations pre-operatively. While encouraging, it should be noted that the performance of the model on patients undergoing ACL reconstruction outside of Scandinavia remains unknown

Aims. This study aims to determine the proportion of patients with end-stage knee osteoarthritis (OA) possibly suitable for partial (PKA) or combined partial knee arthroplasty (CPKA) according to patterns of full-thickness cartilage loss and anterior cruciate ligament (ACL) status. Methods. A cross-sectional analysis of 300 consecutive patients (mean age 69 years (SD 9.5, 44 to 91), mean body mass index (BMI) 30.6 (SD 5.5, 20 to 53), 178 female (59.3%)) undergoing total knee arthroplasty (TKA) for Kellgren-Lawrence grade ≥ 3 knee OA was conducted. The point of maximal tibial bone loss on preoperative lateral radiographs was determined as a percentage of the tibial diameter. At surgery, Lachman’s test and ACL status were recorded. The presence of full-thickness cartilage loss within 16 articular surface regions (two patella, eight femoral, six tibial) was recorded. Results. According to articular cartilage loss and ACL status, 195/293 (67%) were suitable for PKA or CPKA: medial unicompartmental knee arthroplasty (UKA) 97/293 (33%); lateral UKA 25 (9%); medial bicompartmental arthroplasty 31 (11%); lateral bicompartmental arthroplasty 12 (4%); bicondylar-UKA 23 (8%); and patellofemoral arthroplasty (PFA) seven (2%). The ACL was intact in 166 (55%), frayed in 82 (27%), disrupted in 12 (4%), and absent in 33 (11%). Lachman testing was specific (97%) but poorly sensitive (38%) for disrupted/absent ACLs. The point of maximal tibial bone loss showed good interclass correlation (ICC 0.797, 0.73 to 0.85 95% confidence interval (CI); p < 0.001) and was more posterior when the ACL was absent. Maximum tibial bone loss occurring at > 55% of the anterior to posterior distance predicted ACL absence with 93% sensitivity and 91% specificity (area under the curve 0.97 (0.94 to 0.99 95% CI; p < 0.001). Conclusion. ACL status can be reliably determined from a lateral radiograph using the location of maximal tibial bone loss. According to regions of cartilage loss and ACL status, two-thirds of patients with end-stage knee OA could potentially be treated with PKA or CPKA. Cite this article: Bone Joint J 2020;102-B(6):716–726

Aims. The aim of this prospective study was to assess the long-term clinical, radiological, functional, and quality of life (QoL)-related outcome of patients treated with the synthetic Ligament Advanced Reinforcement System (LARS) device for anterior cruciate ligament (ACL) rupture. Methods. A total of 41 patients who underwent ACL reconstruction with the LARS device (mean age 39.8 years (SD 12.1 ); 32% females (n = 13)) were prospectively included between August 2001 and March 2005. MRI scans and radiographs were performed at a median follow-up of 2.0 years (interquartile range (IQR) 1.3 to 3.0; n = 40) and 12.8 years (IQR 12.1 to 13.8; n = 22). Functional and QoL-related outcome was assessed in 29 patients at a median follow-up of 12.8 years (IQR 12.0 to 14.0) and clinically reconfirmed at latest median follow-up of 16.5 years (IQR 15.5 to 17.9). International Knee Documentation Committee (IKDC) and Tegner scores were obtained pre- and postoperatively, and Lysholm score postoperatively only. At latest follow-up, range of motion, knee stability tests, 36-Item Short Form Health Survey (SF-36), and IKDC scores were ascertained. Complications and reoperations during follow-up were documented. Results. Cumulative complication rate was 66% (n = 27), with 11 developing within one year from surgery and 16 after one year (including five patients with both early and late complications). Ten graft failures (24%) and eight cases of reactive synovitis were observed (20%). All 11 patients with early complications and ten with late complications underwent reoperation (including five with another surgical procedure for early complications), amounting to a cumulative reoperation rate of 51% (n = 21). Revision ACL reconstruction was performed in one patient (2.4%). Median IKDC at latest follow-up was 89.7 (IQR 78.2 to 93.1), being significantly worse in the event of previous complications. Lachman test was positive in 56% (n = 15) of reconstructed knees. All norm-based SF-36 items were at or above median at latest follow-up, and did not differ depending on development of complications. Conclusion. Despite good functional and QoL-related results in the long term, the cumulative complication rate of 66%, including graft failures and reactive synovitis, has to be viewed with great concern. Cite this article: Bone Joint J 2022;104-B(2):242–248

Successful anterior cruciate ligament (ACL) reconstructions strive a firm ligament-bone integration. Therefore, the aim of this study was to address in more detail the enthesis as the thriphasic bone attachment of the ACL using a tissue engineering approach. To establish a tissue-engineered enthesis-like construct, triphasic scaffolds embroidered from poly(L-lactide-co-caprolactone) and polylactic acid functionalized with collagen foam were colonized with osteogenically differentiated human mesenchymal stromal cells (hMSCs) and lapine (L) ACL fibroblasts. These triphasic scaffolds with a bone-, a fibrocartilage transition- and a ligament phase were seeded directly after spheroid assembly or with 14 days precultured LACL fibroblast spheroids and 14 days osteogenically differentiated hMSCs spheroids (=longer preculture) and cultured for further 14 days. Cell survival was tested. Collagen type I and vimentin were immunolabeled and the content of DNA and sulfated glycosaminoglycan (sGAG) was quantified. The relative gene expression of tenascin C, type I and X collagens, Mohawk and Runx2 was analyzed. Compared to the LACL spheroids the hMSC spheroids adhered better to the scaffold surface with faster cell outgrowth on the fibers. Collagen type I and vimentin were mainly detected in the hMSCs colonizing the bone zone. The DNA content was generally higher in the bone (hMSCs) than in the ligament zones and after short spheroid preculture higher than after longer preculture whereas the sGAG content was greater after longer preculture for both cell types. The longer precultivated hMSCs expressed more type I collagen in comparison to those only shortly precultured before scaffold seeding. Type I collagen and tenascin C were higher expressed in scaffolds directly colonized with LACL compared to those seeded after longer spheroid preculture. The gene expression of ECM components and transcription factors depended on cell type and preculturing condition. Zonal colonization of triphasic scaffolds using the spheroid method is possible offering a novel approach for enthesis tissue engineering

Aim. Quadrupled hamstring anterior cruciate ligament plasties (4xHp) have been described as having a higher risk of infection than bone patellar tendon bone plasties (BPTBp). There are 2 theories that might explain this phenomenon. One is the presence of sutures in a 4xHp that could act as a foreign body, The other is the more complex preparation of a 4xHp that might lead to higher contamination rates during the process. The objective of the present study was to evaluate the formation of biofilm in these plasties and to compare it between a 4xHp and a BPTBp. The hypothesis was that the presence of sutures in 4xHp would increase the amount of biofilm present in them in comparison to BPTBp. Method. A descriptive in vitro study was conducted. One 4xHp and one BPTBp were prepared. They were subsequently divided into 8 fragments. Three of them were reserved for negative control, and the rest were contaminated with a strain of S. Epidermidis (ATCC 35984) 10–5. Finally, a quantitative analysis was carried out by means of microcalorimetry and sonication with plating. Additionally, a qualitative analysis was carried out by means of electron microscopy. Results. In isothermal microcalorimetry, both contaminated plasties showed the same growth dynamics with a population peak (200uW) at 8h. No significant differences were found between the bacterial growth profiles of 4xHp and BPTBp. The product of sonication was plated and the number of colony forming units per milliliter (CFU/ml) was counted at 24 hours. No significant differences were detected between the 4×Hp (mean +/− sem = 3,5×107 +/− 3450000) and the BPTBp (4,6 ×107 +/− 1,455e+7). With a p value of 0.6667, there were no differences of significance (Mann-Whitney test). In the samples analyzed with electron microscopy, no specific biofilm growth pattern was identified upon comparing BPTBp with 4xHp. Conclusions. There were no significant differences at either the quantitative or qualitative level when comparing bacterial growth in BPTBp and 4xHp. Therefore, the presence of sutures in 4xHp cannot be established as a predisposing factor to higher infection rates. These findings may be justified in the sense that the plasties themselves already behave like foreign bodies. Therefore, the presence of sutures does not increase the possibility of biofilm forming on their surface

Objectives. In this study, we compared the pain behaviour and osteoarthritis (OA) progression between anterior cruciate ligament transection (ACLT) and osteochondral injury in surgically-induced OA rat models. Methods. OA was induced in the knee joints of male Wistar rats using transection of the ACL or induction of osteochondral injury. Changes in the percentage of high limb weight distribution (%HLWD) on the operated hind limb were used to determine the pain behaviour in these models. The development of OA was assessed and compared using a histological evaluation based on the Osteoarthritis Research Society International (OARSI) cartilage OA histopathology score. Results. Both models showed an increase in joint pain as indicated by a significant (p < 0.05) decrease in the values of %HLWD at one week post-surgery. In the osteochondral injury model, the %HLWD returned to normal within three weeks, while in the ACLT model, a significant decrease in the %HLWD was persistent over an eight-week period. In addition, OA progression was more advanced in the ACLT model than in the osteochondral injury model. Furthermore, the ACLT model exhibited a higher mean OA score than that of the osteochondral injury model at 12 weeks. Conclusion. The development of pain patterns in the ACLT and osteochondral injury models is different in that the OA progression was significant in the ACLT model. Although both can be used as models for a post-traumatic injury of the knee, the selection of appropriate models for OA in preclinical studies should be specified and relevant to the clinical scenario. Cite this article: T. Tawonsawatruk, O. Sriwatananukulkit, W. Himakhun, W. Hemstapat. Comparison of pain behaviour and osteoarthritis progression between anterior cruciate ligament transection and osteochondral injury in rat models. Bone Joint Res 2018;7:244–251. DOI: 10.1302/2046-3758.73.BJR-2017-0121.R2

Increasing expectations from arthroscopic anterior cruciate ligament (ACL) reconstructions require precise knowledge of technical details such as minimum intra-femoral tunnel graft lengths. A common belief of having ≥20mm of grafts within the femoral tunnel is backed mostly by hearsay rather than scientific proof. We examined clinico-radiological outcomes in patients with intra-femoral tunnel graft lengths <20 and ≥20mm. Primary outcomes were knee scores at 1-year. Secondarily, graft revascularization was compared using magnetic resonance imaging (MRI). We hypothesized that outcomes would be independent of intra-femoral tunnel graft lengths. This prospective, single-surgeon, cohort study was conducted at a tertiary care teaching centre between 2015–2018 after obtaining ethical clearances and consents. Eligible arthroscopic ACL reconstruction patients were sequentially divided into 2 groups based on the intra-femoral tunnel graft lengths (A: < 20 mm, n = 27; and B: ≥ 20 mm, n = 25). Exclusions were made for those > 45 years of age, with chondral and/or multi-ligamentous injuries and with systemic pathologies. All patients were postoperatively examined and scored (Lysholm and modified Cincinnati scores) at 3, 6 and 12 months. Graft vascularity was assessed by signal-to-noise quotient ratio (SNQR) using MRI. Statistical significance was set at p<0.05. Age and sex-matched patients of both groups were followed to 1 year (1 dropout in each). Mean femoral and tibial tunnel diameters (P =0.225 and 0.595) were comparable. Groups A (<20mm) and B (≥20mm) had 27 and 25 patients respectively. At 3 months, 2 group A patients and 1 group B patient had grade 1 Lachman (increased at 12 months to 4 and 3 patients respectively). Pivot shift was negative in all patients. Lysholm scores at 3 and 6 months were comparable (P3= 0.195 and P6= 0.133). At 1 year both groups showed comparable Cincinnati scores. Mean ROM was satisfactory (≥130 degrees) in all but 2 patients of each group (125–130 degrees). MRI scans at 3 months and 1 year observed anatomical tunnels in all without any complications. Femoral tunnel signals in both groups showed a fall from 3–12 months indicating onset of maturation of graft at femoral tunnel. Our hypothesis, clinical and radiological outcomes would be independent of intra-tunnel graft lengths on the femoral aspect, did therefore prove correct. Intra-femoral tunnel graft lengths of <20 mm did not compromise early clinical and functional outcomes of ACL reconstructions. There seems to be no minimum length of graft within the tunnel below which suboptimal results should be expected

We sought to determine whether smoking affected the outcome of reconstruction of the anterior cruciate ligament. We analysed the results of 66 smokers (group 1 with a mean follow-up of 5.67 years (1.1 to 12.7)) and 238 non-smokers (group 2 with a mean follow-up of 6.61 years (1.2 to 11.5)), who were statistically similar in age, gender, graft type, fixation and associated meniscal and chondral pathology. The assessment was performed using the International Knee Documentation Committee form and serial cruciometer readings. Poor outcomes were reported in group 1 for the mean subjective International Knee Documentation Committee score (p < 0.001), the frequency (p = 0.005) and intensity (p = 0.005) of pain, a side-to-side difference in knee laxity (p = 0.001) and the use of a four-strand hamstring graft (p = 0.015). Patients in group 1 were also less likely to return to their original level of pre-injury sport (p = 0.003) and had an overall worse final 7 International Knee Documentation Committee grade score (p = 0.007). Despite the well-known negative effects of smoking on tissue healing, the association with an inferior outcome after reconstruction of the anterior cruciate ligament has not previously been described and should be included in the pre-operative counselling of patients undergoing the procedure

We reviewed 183 patients who had undergone reconstruction of the anterior cruciate ligament. The incidence of meniscal tears and degenerative change was assessed and related to the timing from injury to surgery. Degenerative change was scored using the French Society of Arthroscopy system. The patients were divided into an early (surgery within 12 months of injury) and a late group (surgery more than 12 months from injury). The late group was also subdivided into four groups of 12-month periods ranging from one year to more than four years after injury. There was a significantly higher incidence of meniscal tears in patients undergoing reconstruction after 12 months compared with those in the early group (71.2% vs 41.7%; p < 0.001). This was due to a large increase in medial meniscal tears in the late group. An increased incidence of degenerative change was also found in the late group (31.3% vs 10.7%; p < 0.001). Analysis of the subgroups showed that the incidence of meniscal tears and degenerative change did not differ significantly when surgery was performed after 12 months from injury. We conclude that reconstruction of the anterior cruciate ligament should be carried out within 12 months of injury to minimise the risk of meniscal tears and degenerative change

There is a trend towards the use of double-bundle techniques for the reconstruction of the anterior cruciate ligament. This has not been substantiated scientifically. The functional outcome of these techniques is equivalent to that of single-bundle methods. The main advantage of a double-bundle rather than a single-bundle reconstruction should be a better rotational stability, but the validity and accuracy of systems for the measurement of rotational stability have not been confirmed. Despite the enthusiasm of surgeons for the double-bundle technique, reconstruction with a single-bundle should remain the standard method for managing deficiency of the anterior cruciate ligament until strong evidence in favour of the use of the double-bundle method is available

Aims. Anterior cruciate ligament (ACL) and multiligament knee (MLK) injuries increase the risk of development of knee osteoarthritis and eventual need for total knee arthroplasty (TKA). There are limited data regarding implant use and outcomes in these patients. The aim of this study was to compare the use of constrained implants and outcomes among patients undergoing TKA with a history of prior knee ligament reconstruction (PKLR) versus a matched cohort of patients undergoing TKA with no history of PKLR. Patients and Methods. Patients with a history of ACL or MLK reconstruction who underwent TKA between 2007 and 2017 were identified in a single-institution registry. There were 223 patients who met inclusion criteria (188 ACL reconstruction patients, 35 MLK reconstruction patients). A matched cohort, also of 223 patients, was identified based on patient age, body mass index (BMI), sex, and year of surgery. There were 144 male patients and 79 female patients in both cohorts. Mean age at the time of TKA was 57.2 years (31 to 88). Mean BMI was 29.7 kg/m. 2. (19.5 to 55.7). Results. There was a significantly higher use of constrained implants among patients with PKLR (76 of 223, 34.1%) compared with the control group (40 of 223, 17.9%; p < 0.001). Subgroup analysis showed a higher use of constrained implants among patients with prior MLK reconstruction (21 of 35, 60.0%) compared with ACL reconstruction (55 of 188, 29.3%; p < 0.001). Removal of hardware was performed in 69.5% of patients with PKLR. Mean operative time (p < 0.001) and tourniquet time (p < 0.001) were longer in patients with PKLR compared with controls. There were no significant differences in rates of deep vein thrombosis, pulmonary embolism, infection, transfusion, postoperative knee range of movement (ROM), or need for revision surgery. There was no significant difference in preoperative or postoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) scores between groups. Conclusion. Results of this study suggest a history of PKLR results in increased use of constrained implants but no difference in postoperative knee ROM, patient-reported outcomes, or incidence of revision surgery. Cite this article: Bone Joint J 2019;101-B(7 Supple C):77–83

Due to unsatisfactory results and reported drawbacks of anterior cruciate ligament (ACL) reconstruction new regenerative approaches based on tissue-engineering strategies are currently under investigation. It was the purpose of this study to determine if a novel silk fiber-based ACL scaffold is able to initiate osteointegration in the femoral and tibial bone tunnels under in vivo conditions. Furthermore we tested if the osteointegration process will be improved by intraoperatively seeding the scaffolds with the autologous stromal vascular fraction, an adipose-derived, stem cell-rich isolate from knee fat pads. In this controlled laboratory study, 33 sheep underwent ACL resection and were then randomly assigned to 2 experimental groups: ACL reconstruction with a scaffold alone and ACL reconstruction with a cell-seeded scaffold. Half of the sheep in each group were randomly chosen and euthanized 6 months after surgery and the other half at 12 months. To analyze the integration of the silk-based scaffold in the femoral and tibial bone tunnels, hard tissue histology and micro-computed tomography measurements were performed. The histological workup showed that in all treatment groups, with or without the application of the autologous stromal vascular fraction, an interzone of collagen fibers had formed between bone and silk-based graft. This collagen-fiber continuity partly consisted of Sharpey fibers, comparable with tendon-bone healing known for autografts and allografts. Insertion sites were more broad based at 6 months and more concentrated on the slightly protruding, bony knoblike structures at 12 months. Histologically, no differences between the treatment groups were detectable. Analysis of micro-computed tomography measurements revealed a significantly higher tissue density for the cell-seeded scaffold group as compared with the scaffold-alone group in the tibial but not femoral bone tunnel after 12 months of implantation. The novel silk fiber-based scaffold for ACL regeneration demonstrated integration into the bone tunnels via the formation of a fibrous interzone similar to allografts and autografts. Histologically, additional cell seeding did not enhance osteointegration. No significant differences between 6 and 12 months could be detected. After 12 months, there was still a considerable amount of silk present, and a longer observation period is necessary to see if a true ligament-bone enthesis will be formed

Abnormal knee kinematics following reconstruction of the anterior cruciate ligament may exist despite an apparent resolution of tibial laxity and functional benefit. We performed upright, weight-bearing MR scans of both knees in the sagittal plane at different angles of flexion to determine the kinematics of the knee following unilateral reconstruction (n = 12). The uninjured knee acted as a control. Scans were performed pre-operatively and at three and six months post-operatively. Anteroposterior tibial laxity was determined using an arthrometer and patient function by validated questionnaires before and after reconstruction. In all the knees with deficient anterior cruciate ligaments, the tibial plateau was displaced anteriorly and internally rotated relative to the femur when compared with the control contralateral knee, particularly in extension and early flexion (mean lateral compartment displacement: extension 7.9 mm (. sd 4.8), p = 0.002 and 30° flexion 5.1 mm (. sd.  3.6), p = 0.004). In all ten patients underwent post-operative scans. Reconstruction reduced the subluxation of the lateral tibial plateau at three months, with resolution of anterior displacement in early flexion, but not in extension (p = 0.015). At six months, the reconstructed knee again showed anterior subluxation in both the lateral (mean: extension 4.2 mm (sd 4.2), p = 0.021 and 30° flexion 3.2 mm (. sd. 3.3), p = 0.024) and medial compartments (extension, p = 0.049). . Our results show that despite improvement in laxity and functional benefit, abnormal knee kinematics remain at six months and actually deteriorate from three to six months following reconstruction of the anterior cruciate ligament

We report the effects of local administration of osteogenic protein-1 on the biomechanical properties of the overstretched anterior cruciate ligament in an animal model. An injury in the anterior cruciate ligament was created in 45 rabbits. They were divided into three equal groups. In group 1, no treatment was applied, in group II, phosphate-buffered saline was applied around the injured ligament, and in group III, 12.5 μg of osteogenic protein-1 mixed with phosphate-buffered saline was applied around the injured ligament. A control group of 15 rabbits was assembled from randomly-selected injured knees from among the first three groups. Each rabbit was killed at 12 weeks. The maximum load and stiffness of the anterior cruciate ligament was found to be significantly greater in group III than either group 1 (p = 0.002, p = 0.014) or group II (p = 0.032, p = 0.025). The tensile strength and the tangent modulus of fascicles from the ligament were also significantly greater in group III than either group I (p = 0.002, p = 0.0174) or II (p = 0.005, p = 0.022). The application of osteogenic protein-1 enhanced the healing in the injured anterior cruciate ligament, but compared with the control group the treated ligament remained lengthened. The administration of osteogenic protein-1 may have a therapeutic role in treating the overstretched anterior cruciate ligament

Reconstruction of the anterior cruciate ligament (ACL) allows to restore stability of the knee, in order to facilitate the return to activity (RTA). Although it is understood that the tendon autograft undergoes a ligamentous transformation postoperatively, knowledge about longitudinal microstructural differences in tissue integrity between types of tendon autografts (ie, hamstring vs. patella) remains limited. Diffusion tensor imaging (DTI) has emerged as an objective biomarker to characterize the ligamentization process of the tendon autograft following surgical reconstruction. One major limitation to its use is the need for a pre-injury baseline MRI to compare recovery of the graft, and inform RTA. Here, we explore the relationship for DTI biomarkers (fractional anisotropy, FA) between knees bilaterally, in healthy participants, with the hypothesis that agreement within a patient's knees may support the use of the contralateral knee as a reference to monitor recovery of the tendon autograft, and inform RTA. Fifteen participants with no previous history of knee injuries were enrolled in this study (age, 26.7 +/− 4.4 years; M/F, 7/8). All images were acquired on a 3T Prisma Siemens scanner using a secured flexible 18-channel coil wrapped around the knee. Both knees were scanned. A 3D anatomical Double Echo Steady State (DESS) sequence was acquired on which regions of interest (ROI) were placed consistent with the footprints of the ACL (femur, posteromedial corner on medial aspect of lateral condyle; tibia, anteromedial to intercondylar eminence). Diffusion images were acquired using fat saturation based on optimized parameters in-house. All diffusion images were pre-processed using the FMRIB FSL toolbox. The footprint ROIs of the ACL were then used to reconstruct the ligament in each patient with fiber-based probabilistic tractography (FBPT), providing a semi-automated approach for segmentation. Average FA was computed for each subject, in both knees, and then correlated against one another using a Pearson correlation to assess the degree of similarity between the ACLs. A total of 30 datasets were collected for this study (1/knee/participant; N=15). The group averaged FA (+/− standard deviation) for the FBPT segmented ACLs were found to equal 0.1683 +/− 0.0235 (dominant leg) and 0.1666 +/− 0.0225 (non-dominant leg). When comparing both knees within subjects, reliable agreement was found for the FBPT-derived ACL with a linear correlation coefficient (rho) equal to 0.87 (P < 0 .001). We sought to assess the degree of concordance in FA between the knees of healthy participants with hopes to provide a method for using the contralateral “healthy” knee in the comparison of autograft-dependent longitudinal changes in microstructural integrity, following ACL reconstruction. Our results suggest that good agreement in anisotropy can be achieved between the non-dominant and dominant knees using DTI and the FBPT segmentation method. Contralateral anisotropy of the ACL, assuming no previous injuries, may be used as a quantitative reference biomarker for monitoring the recovery of the tendon autograft following surgical reconstruction, and gather further insight as to potential differences between chosen autografts. Clinically, this may also serve as an index to supplement decision-making with respect to RTA, and reduce rates of re-injuries

Aims. Proliferation, migration, and differentiation of anterior cruciate ligament (ACL) remnant and surrounding cells are fundamental processes for ACL reconstruction; however, the interaction between ACL remnant and surrounding cells is unclear. We hypothesized that ACL remnant cells preserve the capability to regulate the surrounding cells’ activity, collagen gene expression, and tenogenic differentiation. Moreover, extracorporeal shock wave (ESW) would not only promote activity of ACL remnant cells, but also enhance their paracrine regulation of surrounding cells. Methods. Cell viability, proliferation, migration, and expression levels of Collagen-I (COL-I) A1, transforming growth factor beta (TGF-β), and vascular endothelial growth factor (VEGF) were compared between ACL remnant cells untreated and treated with ESW (0.15 mJ/mm. 2. , 1,000 impulses, 4 Hz). To evaluate the subsequent effects on the surrounding cells, bone marrow stromal cells (BMSCs)’ viability, proliferation, migration, and levels of Type I Collagen, Type III Collagen, and tenogenic gene (Scx, TNC) expression were investigated using coculture system. Results. ESW-treated ACL remnant cells presented higher cell viability, proliferation, migration, and increased expression of COL-I A1, TGF-β, and VEGF. BMSC proliferation and migration rate significantly increased after coculture with ACL remnant cells with and without ESW stimulation compared to the BMSCs alone group. Furthermore, ESW significantly enhanced ACL remnant cells’ capability to upregulate the collagen gene expression and tenogenic differentiation of BMSCs, without affecting cell viability, TGF-β, and VEGF expression. Conclusion. ACL remnant cells modulated activity and differentiation of surrounding cells. The results indicated that ESW enhanced ACL remnant cells viability, proliferation, migration, and expression of collagen, TGF-β, VEGF, and paracrine regulation of BMSC proliferation, migration, collagen expression, and tenogenesis. Cite this article: Bone Joint Res 2020;9(8):457–467

While injury to the posterolateral corner is accepted as a relatively common occurrence associated with rupture of the anterior cruciate ligament, posteromedial meniscocapsular injury has not previously been recognised as such. In a prospective assessment of 183 consecutive reconstructions of the anterior cruciate ligament this injury was observed in 17 cases, giving it an incidence of 9.3%. Clinically, it was associated with a mild anteromedial rotatory subluxation and it is important not to confuse this with posterolateral rotatory subluxation. In no case was this injury identified by MRI. The possible long-term clinical relevance is discussed

We present the results of 17 children of Tanner stage 1 or 2 who underwent reconstruction of the anterior cruciate ligament between 1999 and 2006 using a transphyseal procedure, employing an ipsilateral four-strand hamstring graft. The mean age of the children was 12.1 years (9.5 to 14). The mean follow-up was 44 months (25 to 100). Survival of the graft, the functional outcome and complications were recorded. There was one re-rupture following another injury. Of the remaining patients, all had good or excellent results and a normal International Knee Documentation Committee score. The mean post-operative Lysholm score was 97.5 (. sd. 2.6) and the mean Tegner activity scale was 7.9 (. sd. 1.4). One patient had a mild valgus deformity which caused no functional disturbance. No other abnormality or discrepancy of leg length was seen. Measurements with a KT1000 arthrometer showed no significant difference between the normal and the operated legs. In this small series, transphyseal reconstruction of the anterior cruciate ligament appeared to be safe in these young children

Aims. Different methods of anterior cruciate ligament (ACL) reconstruction have been described for skeletally immature patients before closure of the growth plates. However, the outcome and complications following this treatment remain unclear. The aim of this systematic review was to analyse the outcome and complications of different techniques which may be used for reconstruction of the ACL in these patients. Materials and Methods. We performed a systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. This involved a comprehensive search of PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar databases using the following combinations of keywords, “knee”, “anterior cruciate ligament”, “reconstruction”, “injury”, “children”, “adolescent”, “skeletally immature”, “open physis” and “surgery”. Results. A total of 53 studies met the inclusion criteria and were included for analysis. The overall rate of disturbance of growth after ACL reconstruction was 2.6%, with no statistical difference between transphyseal and physeal-sparing techniques. Physeal-sparing techniques had a lower rate of post-operative complications compared with transphyseal techniques (p = 0.0045). Outcomes assessed were Lysholm score, International Knee Documentation Committee (IKDC) score, the IKDC grade, the Tegner score and the KT-1000. Both techniques had similar clinical outcomes. Conclusions. This review reveals low rates of disturbance of growth after ACL reconstruction in skeletally immature patients. Although limited, the available evidence did not support any particular surgical technique when considering disturbance of growth or clinical outcome. Further randomised controlled trials are needed to investigate the efficacy of differing surgical techniques on outcomes in skeletally immature patients. Cite this article: Bone Joint J 2017;99-B:1053–60

The records of patients aged 50 years or over who underwent primary reconstruction of the anterior cruciate ligament between 1990 and 2002 were reviewed. There were 35 knees in 34 patients that met the inclusion criteria. The mean age of the patients was 57 years (50 to 66) and the mean clinical follow-up was for 72 months (25 to 173). A total of 23 knees were reconstructed with patellar tendon allograft, and 12 with patellar tendon autograft. The mean pre-operative knee extension was 1° (−5° to 10°) and flexion was 129° (125° to 150°) and at follow-up these values were 0° (−5° to 5°) and 135° (120° to 150°), respectively. Pre-operatively there were 31 knees (89%) with a Lachman grade 2+ or 3+. Post-operatively, 33 knees (94%) were Lachman grade 0 or 1+. The mean pre- and post-operative International Knee Documentation Committee scores were 39 (23 to 72) and 90 (33 to 100) respectively. The mean pre- and post-operative Lysholm scores were 50 (18 to 68) and 92 (28 to 100) respectively and the mean University of California Los Angeles activity scores were 8.5 before injury (4 to 10), 4.3 (3 to 6) after injury and 8.3 (4 to 10) post-operatively. There were three graft failures (8.6%) requiring revision. We conclude that reconstruction of the anterior cruciate ligament in carefully-selected patients aged 50 years or over can achieve similar results to those in younger patients, with no increased risk of complications

The aim of the this study was to determine the effect of the knee flexion angle (KFA) during tibial anterior cruciate ligament (ACL) graft fixation on patient reported outcomes, graft stability, extension loss and re-operation following anatomic single-bundle ACL reconstruction. All 169 included patients (mean age 28.5 years, 65% male) were treated with anatomic single bundle ACL reconstruction using patellar tendon autograft and randomized to tibial fixation of the ACL graft at either 0o (n=85) or 30o (n=84). The primary outcome was the Knee Injury and Osteoarthritis Outcome Score (KOOS) two years following surgery. Secondary outcomes were the Marx Activity Scale (MAS), the rate of re-operation, and physical exam findings at one year including KT-1000 and side to side differences in knee extension. The follow-up rate was 82% (n=139) for the primary outcome. Graft failure rate at two years was 1% (n=2, 1 per group). ACL tibial graft fixation at 0o or 30o did not have a significant effect on KOOS scores at two years following ACLR. Patients whose graft was fixed at a knee flexion angle of 0o had greater scores on the Marx Activity Scale (mean 9.6 [95%CI 8.5-10.6] versus 8.0 [95%CI 6.9-9.1, p=0.04) and a greater proportion of patients who achieved the minimal clinical important difference (MCID) for the KOOS pain subscale (94% vs 81%, p=0.04). There was no significant difference in knee extension loss, KT-1000 measurements or re-operation between the two groups. In the setting of anatomic single-bundle ACLR using patellar tendon autograft and anteromedial portal femoral drilling, there was no difference in KOOS scores among patients fixed at 0o and 30o. Patient fixed in full extension did demonstrate higher activity scores at 2 years following surgery and a greater likelihood of achieving the MCID for KOOS pain

Delayed rather than early reconstruction of the anterior cruciate ligament is the current recommended treatment for injury to this ligament since it is thought to give a better functional outcome. We randomised 105 consecutive patients with injury associated with chondral lesions no more severe than grades 1 and 2 and/or meniscal tears which only required trimming, to early (< two weeks) or delayed (> four to six weeks) reconstruction of the anterior cruciate ligament using a quadrupled hamstring graft. All operations were performed by a single surgeon and a standard rehabilitation regime was followed in both groups. The outcomes were assessed using the Lysholm score, the Tegner score and measurement of the range of movement. Stability was assessed by clinical tests and measurements taken with the KT-1000 arthrometer, with all testing performed by a blinded uninvolved experienced observer. A total of six patients were lost to follow-up, with 48 patients assigned to the delayed group and 51 to the early group. None was a competitive athlete. The mean interval between injury and the surgery was seven days (2 to 14) in the early group and 32 days (29 to 42) in the delayed group. The mean follow-up was 32 months (26 to 36). The results did not show a statistically significant difference for the Lysholm score (p = 0.86), Tegner activity score (p = 0.913) or the range of movement (p = 1). Similarly, no distinction could be made for stability testing by clinical examination (p = 0.56) and measurements with the KT-1000 arthrometer (p = 0.93). Reconstruction of the anterior cruciate ligament gave a similar clinical and functional outcome whether performed early (< two weeks) or late at four to six weeks after injury

Recent findings have identified the importance of previously undiagnosed or neglected meniscus lesions in association with anterior cruciate ligament (ACL) injuries (e.g. medial meniscus ramp lesions and posterior root tears of the lateral meniscus). There is increasing biomechanical evidence that they bear the potential to alter both anteroposterior and rotational laxity patterns in ACL injured knees. Few data exist with respect to the presence of these specific tear entities in large series of ACL injured patients. The purpose of the study was to analyze the meniscus tear pattern in a series of ACL injured knees with a special focus on ramp lesions of the medial meniscus and posterior root lesions of the lateral meniscus. The hypothesis was that a significant number of ACL injured patients would display these types of lesions. Data from 358 patients undergoing an ACL reconstruction (227 males /131 females, age: 28±10) were extracted from a center-based registry. The type of ACL tear (partial versus complete) as well as the presence of associated meniscus lesions were documented. Meniscus lesions were classified into the following categories: medial ramp lesions, lateral root lesions, medial ramp and lateral root lesion, other medial meniscus injuries, other lateral meniscus injuries, other bimeniscal injuries. Chi-square tests were used to determine whether the percentage of meniscal lesions differed between types of ACL tear, gender and age (below 21, 21–35, above 35). Significance was set at p < 0.05. Isolated ACL tears were present in 107 (30%) of the operated knees (31 partial; 327 complete). Complete ACL lesions were more likely to present an associated meniscus injury (321 out of 327, 71%) than partial tears (13 out of 31, 42%). The incidence of meniscus injuries which are associated with ACL tears is very high (70%). Previously undiagnosed or neglected meniscus injuries like medial ramp or lateral root tears could be identified in 35% of patients. As such, the hypothesis was confirmed that an important amount of ACL injured knees display this specific intraarticular soft tissue damage. A systematic evaluation of these lesions under arthroscopy should thus be performed and specific repair needs to be evaluated

Anterior cruciate ligament (ACL)-retaining total knee arthroplasty (TKA) has been associated with more physiologic motion patterns, more normal knee kinematics, and higher patient preference than ACL-sacrificing implant designs. However, it remains unclear how many osteoarthritic patients can be expected to have an intact ACL at the time of surgery in order to undergo ACL-retaining TKA. A systematic literature review was performed in November 2018 using the PubMed and EMBASE databases. Papers written in English, with more than 10 adult patients relevant to the research question were included, whereas cadaveric, revision, animal and simulation studies and conference abstracts were excluded. Data on ACL retention during intraoperative assessment or MRI scans were extracted and analysed using proportional meta-analyses. Twenty-six eligible publications (4167 knees) were included: 20 using intraoperative assessment, 4 using MRI, and 2 using both. Intraoperative assessment of the ACL during TKA showed that the ligament was present in 78% (95% confidence interval [CI]: 72–84%) and intact in 55% (95% CI: 45–65%) of the patients examined. MRI scans revealed higher percentages of ACL presence and intactness than intraoperative assessment, with 91% (95% CI: 79–96%) of the ACL being present and 68% (95% CI: 28–92%) intact. Fewer studies reported on MRI results compared to studies reporting on the intraoperative status of the ACL. In conclusion, intraoperative assessment suggests that over half of the osteoarthritic patients have an intact ACL at the time of TKA surgery, some of whom may qualify for bicruciate-retaining arthroplasty. For any figures or tables, please contact authors directly

Ten patients are reported who had sustained a partial rupture of the anterior cruciate ligament in a twisting injury of the knee. Nine of the 10 patients presented with a small effusion and pseudo-locking of the knee which was thought to be due to muscular spasm to prevent further ligamentous injury. The patients were examined clinically, under anaesthesia and by arthroscopy and the signs were found to be remarkably similar to those in patients with a tear of the medial meniscus. The mechanism of injury leading to partial rupture of the anterior cruciate ligament is discussed

We report the clinical outcome and findings at second-look arthroscopy of 216 patients (mean age 25 years (11 to 58)) who underwent anterior cruciate ligament (ACL) reconstruction or augmentation. There were 73 single-bundle ACL augmentations (44 female, 29 male), 82 double-bundle ACL reconstructions (35 female, 47 male), and 61 single-bundle ACL reconstructions (34 female, 27 male). In 94 of the 216 patients, proprioceptive function of the knee was evaluated before and 12 months after surgery using the threshold to detect passive motion test. Second-look arthroscopy showed significantly better synovial coverage of the graft in the augmentation group (good: 60 (82%), fair: 10 (14%), poor: 3 (4%)) than in the other groups (p = 0.039). The mean side-to-side difference measured with a KT-2000 arthrometer was 0.4 mm (-3.3 to 2.9) in the augmentation group, 0.9 mm (-3.2 to 3.5) in the double-bundle group, and 1.3 mm (-2.7 to 3.9) in the single-bundle group: the result differed significantly between the augmentation and single-bundle groups (p = 0 .013). No significant difference in the Lysholm score or pivot-shift test was seen between the three groups (p = 0.09 and 0.65, respectively). In patients with good synovial coverage, three of the four measurements used revealed significant improvement in proprioceptive function (p = 0.177, 0.020, 0.034, and 0.026). We conclude that ACL augmentation is a reasonable treatment option for patients with favourable ACL remnants. Cite this article: Bone Joint J 2014;96-B:1325–32

We carried out a prospective study of 71 patients who had undergone reconstruction of the anterior cruciate ligament with the ABC scaffold. Their mean age was 28 years (18 to 50). All had either sub-acute or chronic traumatic deficiency of the ligament. The mean period of follow-up was five years (four to seven). Assessment included the use of the International Knee Documentation Committee score, the modified Lysholm score, the Tegner Activity score, the Knee Injury and Osteoarthritis Outcome score and measurement with the KT-1000 arthrometer. Two patients had mild recurrent synovitis. There were no infections and no failures of the ligament. During the period of study, two patients sustained a traumatic fracture of a femoral condyle. The implants retained their integrity in both cases. All patients returned to their previous or enhanced levels of daily activity by three months after operation and 56 (79%) achieved their pre-injury level of sporting activity by six months. The patients who were competing in National level sports returned to play at one level less after operation than before. The Lysholm score showed that 58% of the patients (41) were excellent, 34% (24) good, and 8% (6) fair, with a mean post-operative score of 93. According to the International Knee Documentation Committee score, 35% of knees (25) were ‘normal’, 52% (37) ‘nearly normal’ and 13% (9) ‘abnormal’. Complete satisfaction was noted in 90% of patients (64). The development of osteoarthritis and the management of anterior cruciate deficiency associated with laxity of the medial collateral ligament remains uncertain. Our results indicate that in the medium-term, the ABC ligament scaffold is suitable and effective when early and safe return to unrestricted activities is demanded. We acknowledge the current general hostility towards reconstruction of the anterior cruciate ligament with artificial materials following reports of early failure and chronic synovitis associatiated with the production of particulate debris. We did not encounter these problems

The concept of decellularised xenografts as a basis for anterior cruciate ligament (ACL) reconstruction was introduced to overcome limitations in alternative graft sources such as substantial remodelling delaying recovery and donor site morbidity. This study aimed to measure the biomechanical properties of decellularised porcine super flexor tendon (pSFT) processed to create ACL grafts of varying diameters, with a view to facilitating production of stratified ‘off the shelf’ products with specified functional properties for use in ACL reconstructive surgery. Decellularisation was carried out using a previously established procedure, including antibiotic washes, low concentration detergent (0.1% sodium dodecyl sulphate) washes and nuclease treatments. Decellularised pSFTs were prepared to create double-bundle grafts of 7, 8 and 9mm diameter (n=6 in each group). Femoral and tibial fixations were simulated utilising Arthrex suspension devices (Tightrope®) and interference screws in bovine bone respectively. Dynamic stiffness and creep were measured under cyclic loading between 50–250N for 1000 cycles at 1Hz. This was followed by ramp to failure at 200mm/min from which linear stiffness and load at failure were measured. Data were analysed using either 1- or 2-way ANOVA as appropriate with Tukey post-hoc analysis (p<0.05). Significant differences were found between all groups for dynamic stiffness and between 7 & 9mm and 8 & 9mm groups for dynamic creep. Significant differences were also found between 7, 8 & 9mm groups for linear stiffness (167.8±4.9, 186.9±16.6 & 216.3±12.4N/mm respectively), but no significant differences were found between groups for load at failure (531.5±58.9, 604.1±183.3 & 627.9±72.4N respectively). This study demonstrated that decellularised pSFTs possess comparable biomechanical properties to other ACL graft options (autografts and allografts). Furthermore, grafts can be stratified by their diameter to provide varying biomechanical profiles depending on the anatomy and individual needs of the recipient

Aims

Machine-learning (ML) prediction models in orthopaedic trauma hold great promise in assisting clinicians in various tasks, such as personalized risk stratification. However, an overview of current applications and critical appraisal to peer-reviewed guidelines is lacking. The objectives of this study are to 1) provide an overview of current ML prediction models in orthopaedic trauma; 2) evaluate the completeness of reporting following the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) statement; and 3) assess the risk of bias following the Prediction model Risk Of Bias Assessment Tool (PROBAST) tool.

This study evaluated the results of a physeal-sparing technique of intra-articular anterior cruciate ligament (ACL) reconstruction in skeletally immature patients, with particular reference to growth disturbance. Between 1992 and 2007, 57 children with a mean age of 12.2 years (6.8 to 14.5) underwent ACL reconstruction using the same technique. At a mean of 5.5 years (2 to 14) after surgery, 56 patients underwent clinical and radiological evaluation. At that time, 49 patients (87.5%) had reached bony maturity and 53 (95%) achieved A or B according to the IKDC 2000 classification. Four patients had stopped participation in sports because of knee symptoms, and three patients (5.4%) had a subsequent recurrent ACL injury. There was no clinical or radiological evidence of growth disturbance after a mean growth in stature of 20.0 cm (3 to 38). This study demonstrates that ACL reconstruction sparing the physes in children is a safe technique protecting against meniscal tears and giving better results than reconstruction in adults, without causing significant growth disturbance

Aims

In the UK, the agricultural, military, and construction sectors have stringent rules about the use of hearing protection due to the risk of noise-induced hearing loss. Orthopaedic staff may also be at risk due to the use of power tools. The UK Health and Safety Executive (HSE) have clear standards as to what are deemed acceptable occupational levels of noise on A-weighted and C-weighted scales. The aims of this review were to assess the current evidence on the testing of exposure to noise in orthopaedic operating theatres to see if it exceeds these regulations.

More than 250,000 people are suffering from Anterior Cruciate Ligament (ACL) related injuries each year in the US, with a cost of $17–25K/patient. There is an unmet clinical demand for improving grafts/scaffolds to provide biological integration in addition to mechanical support. Currently, no data is available for the utilization of fibrous scaffolds with bimodal distribution for ACL regeneration. The novelty in this study is that it proposes for the first time to investigate the collagen fibril diameter distribution in healthy and injured bovine ACL tissue, and utilization of such structure for scaffold design. Objectives are 1) developing a bovine ACL tear model and measuring the collagen fibril diameter distribution of both healthy and injured ACL tissues, and 2) fabricating scaffolds to mimic the structural properties of healthy and injured ACL tissue. Bovine ACL tissues (1–3 years old) were harvested and characterized for their fibril diameter distribution using Transmission Electron Microscopy (TEM) and biomechanical properties under tension. The electrospun polycaprolactone (PCL) scaffolds were characterized using SEM and mechanical testing. Healthy and injured ACL fibril diameter, and that of PCL scaffolds representing healthy and injured ACL are compared using unpaired student t-test. The proposed fibrous scaffold design represents a significant departure from the conventional unimodal approach, and is expected to have significant contribution to ACL regeneration. These discoveries will serve as the foundation for the development of biomimetic tissue engineering substrates aimed at promoting biological graft fixation

Abstract

We reviewed a single-surgeon series of 300 athletic patients who had undergone reconstruction of the anterior cruciate ligament in order to establish the relationship between the timing of the reconstruction and the incidence of meniscal and chondral pathology. The patients were divided into five groups according to the time from their injury to surgery as follows: less than two months, two to six months, six to 12 months, 12 to 18 months and more than 18 months. The presence of meniscal tears was recorded and chondral pathology was scored according to the system of the French Society of Arthroscopy. There was a significantly higher chance of a medial meniscal tear occurring in patients undergoing reconstruction after one year from their injury (odds ratio (7.99, p = 0.004). The odds of having a lateral meniscal tear did not change significantly with an increasing interval to reconstruction. The chance of patients developing degenerative changes was found to be significantly higher in the groups operated on after six months from injury (odds ratio 4.04, p = 0.005). We advocate that patients with deficiency of the anterior cruciate ligament should be counselled that there is a significant relationship between the duration of the instability of their knee and the subsequent incidence of both chondral changes and meniscal tears. In order to minimise these risks, we recommend that reconstruction be performed within the first year from injury

To report the long term outcome of patients with a partial tear of the anterior cruciate ligament (ACL). We reviewed 26 of 31 athletes who had a diagnosis of acute, incomplete tear of the anterior cruciate ligament (ACL) between November 1986 and December 1991. All patients had arthroscopy and examination under anaesthesia within 8 weeks of acute knee injury, and were included in the study if there were still ACL fibres remaining which resisted anterior tibial translation. We excluded patients with associated major ligamentous lesions. Patients were reviewed by a combination of questionnaire and clinical examination at a mean of 38 months after the index injury (range 18 to 66). At review, 20 patients (77%) had developed some symptoms of knee instability. The number of patients with a positive Lachman’s test had increased from 17 to 18, and those with a positive pivot shift had increased from 9 to 13. Seven patients (27%) had undergone ACL reconstruction, 7 other patients (27%) had been unable to return to sport, and 6 patients (23%) continued to participate in sport, but at a reduced level. Only 6 patients (23%) were able to continue in sport at their pre-injury level without reconstructive surgery. Patients with a tear of the anteromedial bundle of the ACL were more likely to have signs of instability at review and to require ACL reconstructive surgery than patients with a tear mainly affecting the posterolateral bundle. Partial lesions of the ACL, especially when involving the AM bundle, should not be regarded as benign injuries. They often result in symptomatic instability necessitating intra-articular reconstruction of the ACL, and, in the long run, in marked decrease in the level of sports participation

We used single-photon emission computed tomography (SPECT) to determine the long-term risk of degenerative change after reconstruction of the anterior cruciate ligament (ACL). Our study population was a prospective series of 31 patients with a mean age at injury of 27.8 years (18 to 47) and a mean follow-up of ten years (9 to 13) after bone-patellar tendon-bone reconstruction of the ACL. The contralateral normal knee was used as a control. All knees were clinically stable with high clinical scores (mean Lysholm score, 93; mean Tegner activity score, 6). Fifteen patients had undergone a partial meniscectomy and ACL reconstruction at or before reconstruction of their ACL. In the group with an intact meniscus, clinical symptoms of osteoarthritis (OA) were found in only one patient (7%), who was also the only patient with marked isotope uptake on the SPECT scan compatible with OA. In the group which underwent a partial meniscectomy, clinical symptoms of OA were found in two patients (13%), who were among five (31%) with isotope uptake compatible with OA. Only one patient (7%) in this group had evidence of advanced OA on plain radiographs. The risk of developing OA after ACL reconstruction in this series is very low and lower than published figures for untreated ACL-deficient knees. There is a significant increase (p < 0.05) in degenerative change in patients who had a reconstruction of their ACL and a partial meniscectomy compared with those who had a reconstruction of their ACL alone

Introduction: Clinical presentation of mucoid degeneration of the anterior cruciate ligament (MDACL) associated knee flexion limitation and posterior knee pain. Treatment needs an anterior cruciate ligament resection, with some questions about harmlessness of this procedure. Our hypothesis was that arthroscopic MDACL treatment is an effective procedure for pain and mobility but creates some anterior knee laxity. Materials and Methods: This is a retrospective cohort study including 29 cases of MDACL (19 men, 8 women). Mean age was 49 years (range 28 to 68). Mean follow-up was 6 years. Diagnosis was done associated clinical and MRI criteria and was confirmed using Mc Intyre’s arthroscopic criteria. A histological analysis was done in 18 cases. Postoperative functional evaluation was done using IKDC and KOOS score. Knee laxity was appreciated using clinical evaluation and radiological evaluation by TELOS measurement. Statistical analysis was done using Student t-test (level of significance: p< 0.005). Results: Preoperatively, posterior knee pain was present in 23 knees, and knee flexion limitation in 14 cases. In 10 cases, MDACL was initially misdiagnosed with an inappropriate primary operative treatment. None of theses patients have an anterior knee laxity. Partial anterior cruciate ligament resection was done in 12 cases and complete resection in 17 cases. Meniscectomy was associated in 11 cases. In cases with histological study, diagnosis was always confirmed. After resection knee was painless in 27 cases, and knee flexion increase was 21.52°. A positive Lachman’s test was noted after surgery in all cases, (with a positive Jerk test in 8 cases). Postoperative radiological laxity was greater on the operated side (operated knee vs normal knee: 12.64 /4.33 mm, p< 0.001) Two young patients have need secondary an ACL reconstruction. Two old patients have needed secondary knee prosthesis after 2 and 3 years. Mean postoperative IKDC score was 71.19 (range 42.53 to 91.95) and mean postoperative KOOS score was 78.16 (range 26.40 to 99). Statistical analysis have showed better results for patient older than 50 years, after partial resection and for patient without meniscal associated lesions. Discussion: Mucoid degeneration of the anterior cruciate ligament should not be confused with anterior cruciate ligament ganglia. Accurate diagnosis could be done using clinical, MRI and arthroscopic diagnosis criteria’s. Arthroscopic treatment of MDACL is an efficient procedure for knee pain and to restore a better knee flexion. However, this procedure created a signifiant anterior knee laxity and could lead in some cases to knee instability especially in young patients

We have investigated the changes in anterior laxity of the knee in response to direct electrical stimulation of eight normal and 45 reconstructed anterior cruciate ligaments (ACLs). In the latter, the mean time from reconstruction was 26.7 months (24 to 32). The ACL was stimulated electrically using a bipolar electrode probe during arthroscopy. Anterior laxity was examined with the knee flexed at 20° under a force of 134 N applied anteriorly to the tibia using the KT-2000 knee arthrometer before, during and after electrical stimulation. Anterior tibial translation in eight normal and 17 ACL-reconstructed knees was significantly decreased during stimulation, compared with that before stimulation. In 28 knees with reconstruction of the ACL, in 22 of which the grafts were found to have detectable somatosensory evoked potentials during stimulation, anterior tibial translation was not decreased. These findings suggest that the ACL-hamstring reflex arc in normal knees may contribute to the functional stability and that this may not be fully restored after some reconstructions of the ACL

Introduction. Anterior cruciate ligament (ACL) and multiligament knee (MLK) injuries increase the risk of development of knee osteoarthritis and eventual need for total knee arthroplasty (TKA). There is limited data regarding implant use and outcomes in these patients. The aim of this study was to compare the use of constrained implants and outcomes among patients undergoing TKA with a history of prior knee ligament reconstruction (PKLR) to a matched cohort of patients undergoing TKA with no history of PKLR. Methods. All patients with history of ACL or MLK reconstruction who underwent TKA between 2007–2018 were identified in a single institution registry. A matched cohort was identified based on patient age, body mass index (BMI), sex, and year of surgery. The primary outcome measure was utilization of constrained implants. Secondary outcomes included rates of deep vein thrombosis (DVT), pulmonary embolism (PE), infection, postoperative transfusion, postoperative knee range of motion (ROM), revision surgery, and patient reported outcomes (Knee Injury and Osteoarthritis Outcome Score for joint replacement (KOOS, JR). Results. There were 223 patients who met inclusion criteria (188 patients with prior ACL reconstruction, 35 patients with prior MLK reconstruction). Mean age at the time of TKA was 57.2 years (range 31–88). Mean BMI was 29.7 (range 19.5–55.7). Patients with PKLR had a lower Charleston Comorbidity Index compared to controls (p<0.0001). There was a significantly higher use of constrained implants among patients with PKLR (34.1%) compared to the control group (17.9%) (p<0.001). Subgroup analysis showed a higher use of constrained implants among patients with prior MLK reconstruction (60.0%) compared to ACL reconstruction (29.3%) (p<0.001). Removal of hardware at the time of TKA was performed in 69.8% of patients with PKLR. Mean operative time (p<0.001) and tourniquet time (p<0.001) were longer in patients with PKLR compared to controls. There were no significant differences in rates of DVT, PE, infection, transfusion, postoperative knee ROM, or need for revision surgery (p>0.05). There was no significant difference in preoperative or postoperative KOOS, JR scores between groups (p>0.05). Conclusion. Results of this study suggest a history of PKLR results in an increased utilization of constrained implants but no difference in post-operative knee ROM, patient reported outcomes, or incidence of revision surgery

Introduction. A common problem for patients receiving total knee arthroplasty (TKA) is postoperative functional impairment of the joint. This is minimized in bicruciate-retaining (ACL preserving) knee replacements, due to the important role of the anterior cruciate ligament (ACL) in normal kinematic patterns of the knee. We explore ACL sparing TKA by estimating the fraction of osteoarthritic TKA patients with a compatible ACL (assessed intraoperatively), while also examining potential preoperative indicators of ACL status. Method. We retrospectively examined 498 patients with a primary diagnosis of osteoarthritis who underwent a TKA by one surgeon between September 2013 and March 2015. Exclusion criteria included a prior TKA, a unicompartmental knee replacement, or inflammatory arthritis. Extensive preoperative data (within four months of surgery) for each patient was collected (anatomical alignment, extension, flexion, range of motion (ROM), Lachman test, and BMI) in addition to de-identified demographic data. The intraoperative assessment of ACL status (normal/functionally intact, compromised/deficient, or absent) was then obtained from our local database and compared with the preoperative data. IRB exemption was obtained to retrospectively collect data. Results. Intraoperative assessment of ACL status found 73.5% normal ACL, 12.9% compromised ACL, and 13.6% absent ACL. A significant demographic predictor of ACL status was gender (female - more likely intact, male - more likely absent; χ2 = 12.43, P<0.002). Patients with an intact ACL were also shown to have significantly better preoperative extension (χ2=14.83, P<0.022), flexion (F. 2, 469. = 9.93, P < 0.001), and ROM (F. 2, 469. = 9.38, P < 0.001) than those with a compromised ACL. We had a very small number of positive Lachman test results, and therefore could not draw any valid conclusion for preoperative predictive ability of the test. There was no significant difference in age, ethnicity, BMI or preoperative alignment between ACL status groups. Conclusion. Our study found 73.5% of 498 osteoarthritic TKA patients have an intact ACL. The strongest preoperative indicators of ACL status were gender, flexion, and ROM. Taken together, our results highlight a significant percentage of patients who are potential candidates for a bicruciate-retaining TKA

Purpose: Cyclope syndrome is described in the literature as a postoperative complication of arthroscopic anterior cruciate ligament (ACL) grafts, leading to permanent flexion. The discovery of this syndrome in ten patients before reconstruction of the ACL led us to revisit the pathophysiology. Material and methods: Among 250 candidates for ACL grafts, ten presented a positive but dull Lachman-Trillat sign with permanent flexion greater than 10°. The rotation click was negative in two and dull in eight. KT 200 measured differential laxity greater than 4 mm in all. Nine patients were reviewed at consultation, one patient had recently undergone another operation. Clinical and radiographic findings recorded in the patient’s files and operation reports were reviewed by two observers different from the operator. Results: Arthroscopy revealed a partial tear of the ACL in three cases, a scarred ACL nourished by the PCL in five and a full thickness tear of the ACL in two. There was a fibrous barbell nodule inserted on the tibia in all cases, a characteristic feature of cyclope syndrome. The nodule was interposed between the femur and tibia at extension and was resected in all cases. Pathology reported a ligamentoid structure undergoing fibrous organisation. At last follow-up, greater than two years for nine patients, the IKDC rating was A for six patients and B for three patients. None of the patients had a defective extension differential. Discussion: Persistent flexion preoperatively in a patient with a torn anterior cruciate ligament suggests possible presence of a ligamento-fibrous nodule interposing between the femur and tibia at extension. This nodule can go unnoticed at arthroscopy but appears to be unmasked in the Cabott position after partial resection of the subpatellar fat. It is particularly important to look for this nodule when the stump of the torn ACL is not found and the patient has experienced a recent sprain. Since we started looking for this nodule in all cases with resection, we have no longer encountered postoperative cyclope syndrome. Conclusion: This group of arguments strongly suggests that the conditions necessary for the constitution of cyclope syndrome are probably present before reconstruction of the anterior cruciate ligament

We have investigated whether cells derived from haemarthrosis caused by injury to the anterior cruciate ligament could differentiate into the osteoblast lineage in vitro. Haemarthroses associated with anterior cruciate ligament injuries were aspirated and cultured. After treatment with β-glycerophosphate, ascorbic acid and dexamethasone or 1,25 (OH). 2. D. 3. , a significant increase in the activity of alkaline phosphatase was observed. Matrix mineralisation was demonstrated after 28 days and mRNA levels in osteoblast-related genes were enhanced. Our results suggest that the haemarthrosis induced by injury to the anterior cruciate ligament contains osteoprogenitor cells and is a potential alternative source for cell-based treatment in such injury

The clinical and radiological features of 12 knees (10 patients) with congenital absence of the anterior cruciate ligament are presented. The high frequency of this condition in association with other more easily recognised congenital abnormalities of the knee is discussed. It is concluded that congenital absence of the anterior cruciate ligament is more common than generally suspected and is associated with other developmental abnormalities of both bone and soft tissue in the lower limb, particularly around the knee joint

A total of 108 patients with unilateral instability of the knee, associated with rupture of the anterior cruciate ligament, was prospectively randomised for arthroscopic single- or double-bundle reconstruction of the ligament using hamstring tendons. The same postoperative rehabilitation protocol was used for all. The patients were followed up for a mean of 32 months (24 to 36). We measured the anterior laxity and joint position sense at different angles of flexion of the knee to determine whether both bundles in the double-bundle reconstruction contributed to the stability of the joint and proprioception. No significant difference was found between the two groups with regard to anterior laxity measured by the KT-2000 arthrometer with the knee at 20° or 70° flexion nor with regard to proprioception. A notchplasty was required less often in the double- compared with the single-bundle reconstruction. We did not find any advantage in a double-bundle as opposed to a single-bundle reconstruction in terms of stability or proprioception

Objectives. This study aimed to investigate time-dependent gene expression of injured human anterior cruciate ligament (ACL), and to evaluate the histological changes of the ACL remnant in terms of cellular characterisation. Methods. Injured human ACL tissues were harvested from 105 patients undergoing primary ACL reconstruction and divided into four phases based on the period from injury to surgery. Phase I was < three weeks, phase II was three to eight weeks, phase III was eight to 20 weeks, and phase IV was ≥ 21 weeks. Gene expressions of these tissues were analysed in each phase by quantitative real-time polymerase chain reaction using selected markers (collagen types 1 and 3, biglycan, decorin, α-smooth muscle actin, IL-6, TGF-β1, MMP-1, MMP-2 and TIMP-1). Immunohistochemical staining was also performed using primary antibodies against CD68, CD55, Stat3 and phosphorylated-Stat3 (P-Stat3). . Results. Expression of IL-6 was mainly seen in phases I, II and III, collagen type 1 in phase II, MMP-1, 2 in phase III, and decorin, TGF-β1 and α-smooth muscle actin in phase IV. Histologically, degradation and scar formation were seen in the ACL remnant after phase III. The numbers of CD55 and P-Stat3 positive cells were elevated from phase II to phase III. . Conclusions. Elevated cell numbers including P-Stat3 positive cells were not related to collagens but to MMPs’ expressions

The revascularisation and remodelling of allografts used to replace the anterior cruciate ligament in the canine knee were studied by microangiographic, histological and biomechanical methods. The 26 allografts were obtained from the patellar tendons of other dogs and were stored by deep freezing. In a control study a strip of patellar tendon from the same leg was used as an autologous free graft. Microangiography showed that the allografts had been revascularised from the sixth postoperative week, and had later developed an intrinsic vascular pattern similar to that of a normal anterior cruciate ligament. Histologically, the allograft regained a fibrous framework similar to that of a normal ligament, and showed no evidence of immunological rejection. Biomechanical tests on the allograft replacements showed that their mean maximum tensile strength at 30 weeks was about 30% of that of the control ligaments. There were no significant differences between the mechanical properties of the allografts and the autografts

Aims

Joint registries classify all further arthroplasty procedures to a knee with an existing partial arthroplasty as revision surgery, regardless of the actual procedure performed. Relatively minor procedures, including bearing exchanges, are classified in the same way as major operations requiring augments and stems. A new classification system is proposed to acknowledge and describe the detail of these procedures, which has implications for risk, recovery, and health economics.

We identified a series of 128 patients who had unilateral open reconstruction of the anterior cruciate ligament (ACL) by a single surgeon between 1993 and 2000. In all, 79 patients were reviewed clinically and radiologically eight to 15 years after surgery. Assessment included measurement of the Lysholm and Tegner scores, the ACL quality-of-life score and the Short Form-12 score, as well as the International Knee Documentation Committee clinical assessment, measurement of laxity by the KT-1000 arthrometer, a single-leg hop test and standardised radiography of both knees using the uninjured knee as a control. Of the injured knees, 46 (57%) had definite radiological evidence of osteoarthritis (Kellgren-Lawrence grade 2 or 3), with a mean difference between the injured and non-injured knees of 1.2 grades. The median ACL quality-of-life score was 80 (interquartile range (IQR) 60 to 90), the Lysholm score 84 (IQR 74 to 95), the Short Form-12 physical component score 54 (IQR 49 to 56) and the mean Hop Index 0.94 (0.52 to 1.52). In total 58 patients were graded as normal, 20 as nearly normal and one as abnormal on the KT-1000 assessment and pivot-shift testing. Taking the worst-case scenario of assuming all non-attenders (n = 48), two septic failures and one identified unstable knee found at review to be failures, the failure rate was 40%. Only two of the patients reviewed stated that they would not have similar surgery again. Open reconstruction of the ACL gives good, durable functional results, but with a high rate of radiologically evident osteoarthritis

Purpose: Radiologists describe cysts of the anterior cruciate ligament (ACL) as a cystic formation of the cruciate tentorium. The estimated prevalence is 0.2 to 1.3% of patients explored by magnetic resonance imaging. The purpose of this study was to better define the clinical symptoms involved by comparing clinical, radiological and pathological findings. Material and methods: Between February 1996 and April 2000, nine men underwent surgery of the anterior cruciate ligament for cysts. Mean age at surgery was 43 years (26) 54). None of the patients had a history of trauma and one patient had undergone medial meniscectomy 12 months earlier due to meniscosis. Pain had been present for six months to seven years and progressed slowly. It was very specifically related to hyperflexion. Five patients exhibited a moderate effusion and five had a painful joint line. The Lachmann was stiff. Single leg stance plain x-rays were normal. Magnetic resonance imaging demonstrated a poorly delimited heterogeneous destructured aspect of the ACL in seven patients. The suggested diagnosis was “partial tear of the ACL or old tear of the ACL”. A perfectly circumscribed cyst was revealed by the MRI in two cases, lying behind the ACL in the tentorium of the notch. The posterior cruciate ligament had a normal aspect in all cases. Results: All patients underwent arthroscopy. The ACL was deorganised, widened and yellow in eight, with a yellow circumscribed nodule on the posterior aspect in one. An impingement between the ACL and the tentorium of the notch was observed in one case. Total synovectomy of the ACL sheath removing part of the ligamentous fibres was performed in eight cases. An isolated cyst was removed in one. Plasty of the notch was performed in one. Pathology reported degenerative dystrophic lesions in eight cases and haemopigmented villonodulary synovitis in one. All patients were reviewed at a mean follow-up of 14 months (8–48). Pain at hyperflexion had completely subsided and there was no hydrarthrosis. The Lachmann was stiff and symmetrical. Conclusion: The term ACL cyst is probably inappropriate because we were unable to find true cystic formations but rather a spontaneous degenerative process. Synovectomy of the sheath gave good clinical results. MRI findings can be a diagnostic pitfall: a destructured aspect of the ACL without a context of trauma should suggest spontaneous degeneration of the anterior cruciate ligament

There is little evidence examining the relationship between anatomical landmarks, radiological placement of the tunnels and long-term clinical outcomes following anterior cruciate ligament (ACL) reconstruction. The aim of this study was to investigate the reproducibility of intra-operative landmarks for placement of the tunnels in single-bundle reconstruction of the ACL using four-strand hamstring tendon autografts. Isolated reconstruction of the ACL was performed in 200 patients, who were followed prospectively for seven years with use of the International Knee Documentation Committee forms and radiographs. Taking 0% as the anterior and 100% as the posterior extent, the femoral tunnel was a mean of 86% (. sd. 5) along Blumensaat’s line and the tibial tunnel was 48% (. sd. 5) along the tibial plateau. Taking 0% as the medial and 100% as the lateral extent, the tibial tunnel was 46% (. sd. 3) across the tibial plateau and the mean inclination of the graft in the coronal plane was 19° (. sd. 5.5). The use of intra-operative landmarks resulted in reproducible placement of the tunnels and an excellent clinical outcome seven years after operation. Vertical inclination was associated with increased rotational instability and degenerative radiological changes, while rupture of the graft was associated with posterior placement of the tibial tunnel. If the osseous tunnels are correctly placed, single-bundle reconstruction of the ACL adequately controls both anteroposterior and rotational instability

Introduction and Aims: There are more than 200,000 anterior cruciate ligament (ACL) ruptures each year in the United States. The replacements used for ACL repair do not fully recreate the ACL’s function and histological appearance. Therefore, a novel tissue-engineered ligament was designed and evaluated after ACL reconstruction in a rabbit model. Method: Rabbits received tissue-engineered ligaments or tissue-engineered ligaments seeded with primary rabbit ACL cells. The tissue-engineered ligaments were composed of multifilament poly-L-lactide yarn (70 denier) fabricated into novel 24 yarn 3-D braids. Scaffolds were designed to be easily handled and fixed by the surgeon in ACL reconstructions using the suture over the button technique. A continuous scaffold design accommodated the flexibility of intra-articular loads and the rigours of the bone tunnels. The contralateral legs were used as controls. A key parameter for tissue ingrowth was scaffold porosity at 58 ± 9% and mode pore diameter of 183 ± 83 μm. Results: Histological evaluations showed slow collagen tissue infiltration at the surface of the replacement at the four-week time point for both the tissue-engineered ligament and cell-seeded tissue-engineered ligament. At the 12-week time point, both replacements showed collagen ingrowth and remodelling across the entire implant occurred with a thin fibrous capsule. The cell-seeded tissue-engineered ligament demonstrated greater levels of mature collagen ingrowth and healing compared to the non-cell seeded tissue-engineered ligament. The initial tensile strength properties of the scaffold were 332 ± 20 N and 354 ± 68 MPa, which compared well to the rabbit ACL control (314 ± 66 N). The tensile properties of the tissue-engineered ligament and seeded tissue-engineered ligament at four weeks were 67% and 76%, respectively of control. The tensile properties of the biodegradable implant decreased with time for the tissue-engineered and cell seeded tissue-engineered ligament and by 12 weeks was 9% and 30% respectively, as compared to the rabbit ACL control. The 30% strength retention for the tissue-engineered ligament replacements at 12 weeks was greater than reported by others using poly(lactic acid) and polypropylene ligament augmentation devices (LAD) at 12 weeks, with values of 13% and 16% of control strength retention, respectively. Conclusion: The results of this study demonstrate the promise of a novel cell seeded tissue-engineered ligament for anterior cruciate ligament regeneration

It has been suggested that an increased posterior tibial slope (PTS) and a narrow notch width index (NWI) increase the risk of anterior cruciate ligament (ACL) injury. The aim of this study was to establish why there are conflicting reports on their significance. A total of fifty patients with a ruptured ACL and 50 patients with an intact ACL were included in the study. The group with ACL rupture had a statistically significantly increased PTS (p < 0.001) and a smaller NWI (p < 0.001) than the control group. When a high PTS and/or a narrow NWI were defined as risk factors for an ACL rupture, 80% of patients had at least one risk factor present; only 24% had both factors present. In both groups the PTS was negatively correlated to the NWI (correlation coefficient = -0.28, p = 0.0052). Using a univariate model, PTS and NWI appear to be correlated to rupture of the ACL. Using a logistic regression model, the PTS (p = 0.006) and the NWI (p < 0.0001) remain significant risk factors. From these results, either a steep PTS or a narrow NWI predisposes an individual to ACL injury. Future studies should consider these factors in combination rather than in isolation

In a prospective study, 41 consecutive patients with a partial tear of the anterior cruciate ligament, diagnosed by arthroscopy, were reviewed after an average of 17 months, having been in plaster for six weeks after injury. Their average age was 29 years and review included clinical examination, measurement of anterior and posterior laxity with the Stryker knee laxity tester as well as evaluation of knee function and activity level. Twenty-one patients had unstable knees at follow-up; the mean total anteroposterior laxity for these patients was 12.6 +/- 3.9 mm compared with 7.1 +/- 4.3 mm for the normal knee. Most patients had few symptoms, but there was a significant reduction in the mean level of activity in the unstable group

Introduction. Rupture of the anterior cruciate ligament (ACL) is a common injury and often presents with a typical injury pattern. Historic literature has shown that the accuracy of diagnosis of ACL ruptures is poor at the initial medical consultation despite the history of injury strongly suggesting an ACL injury. The aims of this study were to determine: if the accuracy of diagnosis of ACL ruptures at initial presentation has improved over the last decade; grade of medical staff at initial and subsequent consultations; the mechanism of injury; and the subsequent delay in diagnosis and definitive treatment. Materials and Methods. One hundred and thirty two consecutive patients who underwent ACL reconstruction between January 2005 and January 2009 were analysed using prospective collected data. The mean age of the patients was 29 years (12-57). Sixteen patients were excluded due to chronic ACL injury (15). Results. One hundred and sixteen patients (117 ACL ruptures) were included in the analysis. A typical injury pattern was documented in 87 (75%) of cases. The most common sporting activities associated with an ACL injury were football (35.3%), skiing (21.6%), rugby (10.3%) and other (32.8%). The vast majority of patients (68.1%) sought medical attention within 1 week from time of injury. The diagnosis of an ACL rupture was made in 33 cases (28%) at the initial medical consultation. The diagnosis was made in 13 (11%) of cases with the use of MRI and 6 (5%) cases at arthroscopy. The most common diagnoses made in cases of failed ACL rupture diagnosis were medial meniscal tear (10.3%), medial collateral ligament injury (7.8%) and none (33.6%). The mean time to diagnosis was 21 weeks (0-192) and the mean time to ACL reconstruction was 44 weeks (1-240). Conclusions. Despite a typical mechanism of injury leading to ACL rupture the rate of initial diagnosis remains poor. This often leads to an unnecessary delay in diagnosis and subsequent treatment. Possible reasons for this are discussed

Introduction. Cruciate retaining knee replacements are only implanted into patients with “healthy” ligaments. However, partial anterior cruciate ligament (ACL) tears are difficult to diagnose with conventional MRI. Variations of signal intensity within the ligament are suggestive of injury but it is not possible to confirm damage or assess the collagen alignment within the ligaments. The potential use of Magic Angle Directional Imaging (MADI) as a collagen contrast mechanism is not new, but has remained a challenge. In theory, ligament tearing or joint degeneration would decrease tissue anisotropy and reduce the magic angle effect. Spontaneous cruciate ligament rupture is relatively common in dogs. This study presents results from ten canine knees. Methods. Ethical approval was obtained to collect knees from euthanized dogs requiring a postmortem (PM). A Siemens Verio 3T MRI scanner was used to scan a sphere containing the canine knees in 9 directions to the main magnetic field (B. 0. ) with an isotropic 3D-T1-FLASH sequence. After imaging, the knees were dissected and photographed. The images were registered and aligned to compare signal intensity variations. Segmentation using a thresholding technique identified voxels containing collagen. For each collagen-rich voxel the orientation vector was computed using Szeverenyi and Bydder's method. Each orientation vector reflects the net effect of all fibers comprised within a voxel. The assembly of all unit vectors represents the fiber orientation map and was visualised in ParaView using streamlines. The Alignment Index (AI) is defined as a ratio of the fraction of orientations within 20° (solid angle) centred in that direction to the same fraction in a random (flat) case. By computing AI for a regular gridded orientation space we can visualise differences in AI on a hemisphere. AI was normalised so that AI=0 indicates isotropic collagen alignment. Increasing AI values indicate increasingly aligned structures: AI=1 indicates that all collagen fibers are orientated within the cone of 20° centred at the selected direction. Results. Dogs cranial cruciate ligament (CCL) is similar to human ACL. It's composed of an anteromedial (AM) bundle and a posterolateral (PL) bundle. Two knees were damaged with partial CCL tears, the PL bundle was intact but the AM bundle was torn. Paraview streamlines of the CCL for healthy and damaged knees differ. The healthy knee has continuous fiber tracts with no ligament disruption. In the AM bundle fibers are discontinuous and the PL bundle fibers are continuous as expected in a partially torn CCL. The AI for healthy (mean AI=0.25) and damaged CCL (mean AI= 0.075) is significantly different (p<0.01). The damaged AM bundle has a more diffuse spread of less aligned fibers compared to the more concentrated and aligned PL fiber bundle. Conclusion. This study demonstrates the first visualisation of a CCL partial tear using MADI. Combined with AI, our scanning technique offers a tool to visualise and quantify changes in collagen fiber orientation. Thus, MRI can be used to improve the diagnosis and quantification of partial ligament tears in the knee

Purpose of the study: Anterior cruciate ligament (ACL) navigation systems are based on two underlying principles: «statistical» anatomic position and isometric anatomic (anatomometric) positioning. The purpose of this study was to demonstrate that an anatometric positioning of the transplant can be achieved, in other words, that the transplant can be positioned in the original anatomic air of the ligament insertion while preserving an optimal isometry without notch impingement. This study was also conducted to compare conventional systems with a computer-assisted system. Material and methods: This study was conducted on thawed fresh-frozen cadaver knee specimens with > 120° flexion. The computer-assisted protocol for ACL surgery was applied to ten knee specimens. The original anatomic insertions of the ACL were dissected then inserted at the appropriate points into the computer display. The tibial and femoral insertion points of two classical aiming devices were recorded. These points were compared with the original anatomic insertion. Results: For the tibia: classical aiming methods proposed a point of insertion posterior to the anatomic insertion for eight knees and within the frontiers of the anatomic insertion for two, in line with the anterior border of the posterior cruciate ligament. The computer-designated point of insertion for the tibial fixation was always within the anterior third of the ACL insertion, generally medially. For the femur, the transition (or isometric) line ran across the anatomic femoral insertion in all knees. It was observed that in all cases, the surgeon could choose an anatomic insertion with lesser anisometry by situating the insertion in the distal part of this line: for nine knees, the computer-designated femoral point was anatomic and with lesser anisometry. The Acufex aiming device produced better anisometry (my=4 mm) than the Arthrex device (my=6 mm) but with a less favorable anisometry curve. Discussion: The notion of anatometry is compatible with computer-assisted surgery. This study demonstrated that the computer-designated tibial point of insertion is more anterior and medial than the conventional aiming points. This is a potential choice if the absence of a notch impingement can be visualized: Howel described a manual fluoroscopic method. In our opinion, at the present time, optimal choice of the femoral point to achieve the desired anisometric curve is strictly operator-dependent

Abstract

We reviewed 195 knees in 167 patients at least 20 years after a rim-preserving meniscectomy. They were considered in two groups: 102 knees had had an intact anterior cruciate ligament (ACL), and 93 had had an unrepaired rupture. More patients with a ruptured ACL had downgraded their sport activity by five years after meniscectomy. The incidence of radiographic osteoarthritis was about 65% at 27 years in patients with a ruptured ligament, and 86% in those followed up for over 30 years. In the ligament-deficient group 10% had had operations for osteoarthritis, and another 28% had had other operations, mainly further meniscectomies. Only 6% of those with an intact ligament had needed a second operation after meniscectomy and at long-term follow-up 92% of them were satisfied or very satisfied. Only 74% of the ligament-deficient patients were satisfied with their result. The long-term outcome after rim-preserving meniscectomy depends mainly upon the state of the anterior cruciate ligament

Introduction: Rupture of the anterior cruciate ligament (ACL) is a common injury and often presents with a typical injury pattern. Historic literature has shown that the accuracy of diagnosis of ACL ruptures is poor at the initial medical consultation despite the history of injury strongly suggesting an ACL injury. The aims of this study were to determine: if the accuracy of diagnosis of ACL ruptures at initial presentation has improved over the last decade; grade of medical staff at initial and subsequent consultations; the mechanism of injury; and the subsequent delay in diagnosis and definitive treatment. Materials and Methods: One hundred and thirty two consecutive patients who underwent ACL reconstruction between January 2005 and January 2009 were analysed using prospective collected data. The mean age of the patients was 29 years (12–57). Sixteen patients were excluded due to chronic ACL injury (15). Results: One hundred and sixteen patients (117 ACL ruptures) were included in the analysis. A typical injury pattern was documented in 87 (75%) of cases. The most common sporting activities associated with an ACL injury were football (35.3%), skiing (21.6%), rugby (10.3%) and other (32.8%). The vast majority of patients (68.1%) sought medical attention within 1 week from time of injury. The diagnosis of an ACL rupture was made in 33 cases (28%) at the initial medical consultation. The diagnosis was made in 13 (11%) of cases with the use of MRI and 6 (5%) cases at arthroscopy. The most common diagnoses made in cases of failed ACL rupture diagnosis were medial meniscal tear (10.3%), medial collateral ligament injury (7.8%) and none (33.6%). The mean time to diagnosis was 21 weeks (0–192) and the mean time to ACL reconstruction was 44 weeks (1–240). Conclusions: Despite a typical mechanism of injury leading to ACL rupture the rate of initial diagnosis remains poor. This often leads to an unnecessary delay in diagnosis and subsequent treatment. Possible reasons for this are discussed

Purpose of the study: Cysts are rarely identified in the anterior cruciate ligament; the pathogenic mechanisms involved are poorly understood. We investigated the anatomic and clinical presentation. Material and methods: This retrospective analysis included 24 patients, seven women and seventeen men managed in a single center from 1998 to 2004. Mean patient age was 45 years (range 25–74 years). All patients complained of pain. A preoperative MRI was available for all patients. Mean follow-up was 25 months (range 6–48 months). Arthroscopic procedures were used for 17 patients and the IKDC subjective score was determined preoperatively in all. Radioguided (US or CT) puncture was performed for seven patients associated with corticosteroid injections. Results: On the MRI, there were 16 infiltrating cysts and eight cystic formations. Surgical treatment (n=17) was performed for 13 infiltrative cysts and for four cystic formations. There were two cases of recurrence. Outcome was poor after puncture (two puncture failures, three recurrences and one vascular complication). Discussion: Two forms of cysts of the ACL can be demonstrated by MRI. The clinical presentation may not be different but the therapeutic management should be. The cystic formation is an indication for puncture, with arthroscopic treatment in the event of failure. For infiltrating cysts, complete resection of the cyst during an arthroscopic procedure is indicated, sometimes associated with resection of the ACL. Puncture yields poor results

Introduction. This study explores whether subjects with bicruciate retaining TKRs (BiCR) have more normal knee biomechanics during level walking and stair ascent than subjects with posterior cruciate retaining TKRs (PCR). Due to anterior cruciate ligament (ACL) preservation, we expect BiCR subjects will not show the reduced flexion and altered muscle activation patterns characteristic of persons with TKRs. Methods. Motion and electromyography (EMG) data were collected during level walking and stair climbing for 16 BiCR subjects (4/12 m/f, 65±3 years, 30.7±7.0 BMI, 8/8 R/L), 17 PCR subjects (2/15 m/f, 65±7 years, 30.4±5.1 BMI, 7/10 R/L), and 17 elderly healthy control subjects (8/9 m/f, 55±10 years, 25.8±4.0 BMI, 10/7 R/L), using the point cluster marker set. Surface EMG electrodes were placed on the vastus medialis obliquus (VMO), rectus femoris (RF), biceps femoris (BF), and semitendinosus (ST) muscles. EMG data are reported as percent relative voluntary contraction (%RVC), normalized to the average peak EMG signals during level walking. Statistical nonparametric mapping was used for waveform analysis. Results. Both TKR groups were older, and PCR subjects had higher BMI than control subjects (p≤0.020). The BiCR group walked slower and with shorter stride lengths than controls (p≤0.012). During level walking, BiCR subjects had less knee extension and posterior tibial displacement than controls (95–98%, 96–100% gait cycle, p=0.003, 0.001). PCR subjects showed higher flexion mid-stance than controls (36–44% gait cycle, p=0.001) and more external rotation (66–69% gait cycle, p=0.003). Both TKR groups had smaller extension moment peaks (PCR 5, 59–75, 96%, BiCR 61–78, 95–97% stance, p≤0.007, 0.003) than the control group. The BiCR group had smaller adduction and external rotation moment peaks (20–24%, 10–18% stance, p=0.003, 0.001) compared with controls. During stair climbing, BiCR subjects displayed more external tibial rotation (4–16% stance), more knee abduction (36–52% stance), and a lower adduction moment peak (24–34% stance) compared to healthy controls (p≤0.005). TKR subjects from both groups showed lower flexion moment peaks than controls (PCR 24–35%, BiCR 24–28% stance, p≤0.001, 0.004). For EMG, PCR subjects had more BF activity during stair ascent versus level walking than healthy subjects (56–74% stance, p≤0.001). Discussion. BiCR and PCR showed more similarities than expected. Both had altered kinematics and kinetics compared to controls, suggesting some intrinsic extensor mechanism weakness, possibly an aftereffect of osteoarthritis. The EMG results agreed accordingly, as both TKR groups showed (non-significant) decreased quadriceps activity during stair climbing. Interestingly, PCR subjects also had more BF activity during stair than healthy controls, a trend that is common for both TKR subjects and people with ACL deficiency. On the other hand, although BiCR subjects were significantly more externally rotated in early stance phase for stair climbing, their rotation patterns began to align more closely to those of the healthy control subjects at lower flexion angles where the ACL should come into play. In conclusion, ACL retention in TKRs does not correct the extensor mechanism deficits commonly found in TKR patients, although it has some effect on secondary knee kinematics and hamstring muscle activity

The efficacy of thermal modulation of collagen utilizing an electrothermal device to treat low to moderate demand patients with mid-substance anterior cruciate ligament tears was studied. Ten patients with partial ACL tear were treated with thermal modulation of the ligament. A chondral pick was utilized to create vascular inlet channels within the intercondylar notch. The mean follow up was 18 months (range of 12 to 36 months). The patients ranged from 21 to 47 years of age. On the physical examination and KT-1000 testing eight patients had good to excellent clinical results, one patient an acute traumatic failure at 18 months and one a poor outcome. However the KT-1000 results deteriorated after one year. There may be some benefit in treating moderate to low demand patients with this technology; however the long term results are unknown. There have been very few studies evaluating the efficacy of thermal modulation of the ACL, and those studies have included patients who have previously undergone ACL reconstruction and have developed a loose graft. To our knowledge, this is the only study that evaluates primary ACL injuries, and utilizes vascular inlet channels to allow cellular population of the treated ACL

Introduction: Medial unicompartmental knee replacement (UKR) is a successful procedure in the management of early osteoarthrosis. This procedure is not usually indicated in patients who have insufficiency of the anterior cruciate ligament (ACL). However, a problem arises when, after a UKR, an ACL rupture occurs, and instability develops. A technique is described to stabilise the knee and possibly avoid conversion to total knee replacement. Methods: Three patients underwent arthroscopic ACL reconstruction. Only semitendinosus tendon was used. The proximal fixation was with a Mulch screw (Biomet) and the distal fixation was with two screws and washers. A post-operative, standard, accelerated rehabilitation programme was used in all three. Results: After two years, two patients continued playing doubles tennis, and one continued as a dancing instructor. Conclusions: While an ACL-related instability is a contraindication to undertaking a UKR, the disruption of an ACL in a well functioning UKR and the development of instability need not necessarily force the conversion to TKR. Using a modified hamstring reconstruction it was possible to stabilise the knee and maintain the UKR function

We have measured anterior and posterior displacement in 563 normal knees and 487 knees with chronic deficiency of the anterior cruciate ligament (ACL). We performed stress radiography using a simple apparatus which maintained the knee at 20° of flexion while a 9 kg load was applied. There was no significant difference in posterior translation dependent on the condition of the ACL. Measurement of anterior translation in the medial compartment proved to be more reliable than in the lateral compartment for the diagnosis of rupture of the ACL, with better specificity, sensitivity and predictive values. We have classified anterior laxity based on the differential anterior translation of the medial compartment and identified four grades in each of which we can further distinguish four subgrades for laxity of the lateral compartment. Within each of these subgroups, either internal or external rotation may dominate and sometimes there is a major translation of both compartments. Radiological evaluation of displacement of the knee in 20° of flexion provides conclusive evidence of rupture of the ACL. A detailed study of pathological displacement is the basis for a classification of laxity. It is then possible to decide for each type of laxity, the surgical treatment which is specifically adapted to the lesion, and to define a reference value for judging outcome

We studied bone-tendon healing using immunohistochemical methods in a rabbit model. Reconstruction of the anterior cruciate ligament was undertaken using semitendinosus tendon in 20 rabbits. Immunohistochemical evaluations were performed at one, two, four and eight weeks after the operation. The expression of CD31, RAM-11, VEGF, b-FGF, S-100 protein and collagen I, II and III in the bone-tendon interface was very similar to that in the endochondral ossification. Some of the type-III collagen in the outer layer of the graft, which was deposited at a very early phase after the operation, was believed to have matured into Sharpey-like fibres. However, remodelling of the tendon grafted into the bone tunnel was significantly delayed when compared with this ossification process. To promote healing, we believe that it is necessary to accelerate remodelling of the tendon, simultaneously with the augmentation of the ossification

The management of symptomatic single bundle Anterior Cruciate Ligament (ACL) ruptures is still a surgical dilemma. Preservation of the intact fibres of the ACL bundle is considered to be a possible source of reinnervation of the ACL autograft which reflects on better proprioceptive knee control after major ligament reconstruction. Results of a prospective study of 67 patients who had a double stranded but single bundle Anterior Cruciate Ligament (ACL) reconstruction for partial ACL ruptures are presented. There were 43 males and 24 females in this study with a mean age at the time of injury of twenty-five years (14 – 40). Eight played sport professionally and thirty-four played at a competitive level. A valgus twisting force was the most common mechanism of injury. Mean injury to operation time was 7.5 weeks (2–12). All procedures were done arthroscopically without using tourniquet, but using an arthroscopy pump and irrigation fluid containing adrenaline. The semitendinosis hamstring graft was used in all reconstructions. The mean follow-up period was 3.3 years (2–5.4). There was one major complication, who developed a reflex sympathetic dystrophy following a saphenous nerve neuroma. The Quality of Life (QOL) score was assessed using the Mohtadi index. The mean pre-operative QOL score of 30 (13–50) was improved to 93 (70–100) post-operatively. Fifty patients were able to return to their previous sporting level at a mean duration of 9 months (6–12). Preservation of mechanoreceptors by performing a double stranded, single bundle ACL reconstruction in partial ACL ruptures in high demand patients yields good results and enables early return to high demand sports

Aims: To determine the difference between macroscopic and microscopic appearances of the anterior cruciate ligament (ACL) in patients with osteoarthritis undergoing total knee replacement. Methods: Patients admitted for routine total knee replacement (TKR) for osteoarthritis were assessed. The integrity of the ACL was noted as normal, moderately damaged (fissured) or complete rupture on a macroscopic level at the time of surgery. The ACL was sacrificed as a normal step in the operation and sent for histological analysis. The macroscopic and microscopic findings of ACL histology were compared using a common grading system (Grade 1 = normal, Grade 2 = moderately diseased, Grade 3 = severely diseased). Results: The sample contained 48 patients, 17 male and 31 female, age range 55–87 years (mean 73). After exclusions, at surgery 7 ACL ruptures and 8 moderately diseased ligaments (defined by the presence of visible fissuring) were found despite negative pivot shift tests preoperatively. Of the 30 ACL’s that were found to be macroscopically normal, 22 of these (73%) were microscopically moderately or severely diseased. Conclusion: We have found that a macroscopically normal ACL does not necessarily equate to microscopic integrity in the presence of osteoarthritis. This is an important consideration given the current trend towards unicompartmental knee replacement and highlights the possible need for investigation with appropriate imaging (MRI) and arthroscopy prior to this specific surgery

We examined whether somatosensory evoked potentials (SEPs) were detectable after direct electrical stimulation of injured, reconstructed and normal anterior cruciate ligaments (ACL) during arthroscopy under general anaesthesia. We investigated the position sense of the knee before and after reconstruction and the correlation between the SEP and instability. We found detectable SEPs in all ligaments which had been reconstructed with autogenous semitendinosus and gracilis tendons over the past 18 months as well as in all cases of the normal group. The SEP was detectable in only 15 out of 32 cases in the injured group, although the voltages in the injured group were significantly lower than those of the controls. This was not the case in the reconstructed group. The postoperative position sense in 17 knees improved significantly, but there was no correlation between it and the voltage. The voltage of stable knees was significantly higher than that of the unstable joints. Our findings showed that sensory reinnervation occurred in the reconstructed human ACL and was closely related to the function of the knee

Purpose: The purpose of our tissue engineering work was to produce a substitute for the anterior cruciate ligament (ACL) in laboratory cultures for human implantation and to conduct fundamental studies on healing mechanisms. Material: We used cells isolated from ACL biopsies obtained from the host, type I bovine collagen, and two bone blocks to produce ACL in culture. Methods: Several layers of collagen containing host autologous ACL cells were superposed and linked to two bones that were placed on either side, according to a process currently being patented. The cells, or fibroblasts, enter into contact with the collagen matrix and start remodelling it, in the laboratory, before implantation. This ACL produced by tissue engineering can be ready for implantation 10–12 days after isolating the autologous cells from a ruptured ACL. Results: Implantation of autologous ACL reconstructs was successful in eight goats. Histological analysis of the implanted grafts showed permanent integration into the tissues after 1–13 months. Th synovial membrane was reformed and rapidly vascularised, about one month after the graft. Thereafter, remodelling of the collagen matrix led to the formation of a very dense network of fibres, organised in bundles, very comparable to the normal histological aspect of the ACL. The bone blocks were also integrated by incorporation into the femur and tibia of the host. Sharpey fibres were present at the bone-ligament surface and a well structured fibro-cartilage was observed. In addition, the synovial membrane around the graft was innervated five months after implantation, suggesting that propioception could be recovered over time. Finally, progressive gain in force reached 20 – 36% of the normal ACL, 9 to 13 months after implantation;. Discussion: These promising data demonstrate that an autologous ACL with an interesting potential for regeneration can be produced in the laboratory, avoiding the risk of rejection and sparing healthy knee structures, thus favouring more rapid functional rehabilitation. Conclusion: Tissue engineering is a new avenue of research with potential applications in orthopaedic surgery, particularly for reconstruction of the ACL

Purpose of the study: This work examined the clinical, radiological, and videoarthroscopic features of partial tears of the anterior cruciate ligament (ACL) and analysed results of ligament plasties. Material and method: Mean age was 32 years. Patients complained of instability accidents in 70% of cases. The Lachman test was noted soft endpoint to + or ++ in 90%. A palpable click was found in 60% but was considered severe in two cases only. Telos laxity was moderate (about 5 mm) in 80%. Mean time to surgery was relatively short (9 months). Arthroscopic exploration revealed rupture of the anteromedial head of the ACL with preservation of the posterolateral component. There was a meniscal injury in nine knees. Early in our experience we performed a total plasty for nine patients (six using hamstring tendons and three with the patellar tendon). At the present time, we spare the posterolateral head and make a partial plasty of the anteromedial head (11 knees: 3 harvesting a single tendon [gracilis] and eight using the gracilis and the semitendious) associated with lateral reinforcement in five. Results: Mean follow-up was 30 months; 30% of patients had knee pain. Three knees exhibited a soft endpoint (+) all after a total plasty. There were no cases of quadriceps motion deficit or amyotrophy. Discussion: The existence of partial tears of the ACL were confirmed in this series. This type of tear corresponds to an objective condition seen arthroscopically and also to precise clinical presentations and biological findings: minor signs of instability with moderate objective anterior instability to the order of 5 mm. Conclusion: Considering this work and a review of the literature, the diagnosis of partial tears of the ACL could be established from the physical examination and measurements of anterior knee laxity. Reconstruction of a single head provides better results than complete reconstruction which would sacrifice an intact portion of the ACL

In an animal model we determined the strength of anterior cruciate ligaments (ACL) after section and repair by four different methods and compared it with that of the intact ligament. The standard suturing technique of multiple loops through the ligament stumps was used. Stronger suture material did not give a stronger repair. Wrapping a fine polyester mesh around the ligament or placing it between the bundles before suture increased the strength of the repair. This modification, allied to protective rehabilitation, may reduce the failure rate of acute ACL repairs

Cell sheets are manufactured from a high-density cell layer stabilized by its own freshly produced extracellular matrix (ECM). They could serve as versatile scaffolds for tissue repair. Unfortunately, their production often remains time-consuming requiring weeks of culturing. Ligament cell sheets are so far barely available. Regarding musculoskeletal tissues exposed to high repetitive biomechanical forces, the stability of cell sheets is insufficient. It could help to combine them with a biomechanical competent scaffold e.g. produced by an embroidering technique. Hence, we wanted to (1) develop a very rapid strategy to produce ACL ligamentocyte sheets within 24 h by using a thermoresponsive polymer surface, (2) use the sheets for scaffold seeding and (3) reflect the fibrocartilaginous transition zone of an ACL enthesis by combining sheets of ligamentocytes with chondrocytes or chondrogenic precursor cells as a strategy for directed seeding of two cell types on topologically different scaffold areas.

Different cell numbers of lapine ACL ligamentocytes (L-ACLs), lapine articular chondrocytes (L-ACs) and human mesenchymal stromal cells (H-MSCs) were used for sheet formation. Experiments were performed with novel, self-assembled poly(glycidyl ether) (PGE) brushes based on random glycidyl methyl ether and ethyl glycidyl ether copolymers on polystyrene 12-well cell culture plates, which allow rapid sheet formation within 24 h. Uncoated plates served as controls. Temperature-triggered detachment was performed by 10 min incubation with PBS at ambient temperature before treatment with fresh warm PBS for 5 min at 37 degrees Celsius. Harvested cell sheets were transferred on polyglycolic acid (PGA) or embroidered poly-lactic acid / poly-co-caprolactone (PLA/P[LA-CL]) scaffolds, functionalized with collagen foam and fluorine gas treatment (prepared at the IPF in Dresden and the FILK in Freiberg). Cell distribution, growth, vitality and synthesis of ECM components were monitored up to 7 days. Cell numbers required for sheet preparation (3.9 cm2) depended strongly on the cell type (L-ACLs: 0.395 mio/cm2, L-AC: 0.342 mio/cm2, H-MSCs: 0.131 mio/cm2) and was highest for L-ACLs. The majority of cells survived sheet assembly, detachment, transfer onto the scaffolds and culturing. Cells migrated from the sheets into the scaffolds and spread through the scaffolds. L-ACLs and L-ACs produced ECM and maintained their phenotypes (type II collagen and sulfated glycosaminoglycans in L-AC sheets, decorin and tenascin C in L-ACL sheets). The presence and distribution of two cell types in scaffold cocultures (L-ACLs and H-MSCs) was proven by anti-human vimentin labeling. Hence, the PGE brush surface allows rapid formation (24 h) of cell sheets.

Sixty-five knees were subjected to a kinematic analysis using the instant-centre technique in order to determine the effect of deficiency of the anterior cruciate ligament on the biomechanics of active movement in the knee. The instant-centre pathway in acute ruptures of the anterior cruciate ligament was found to have a specific abnormality. This corresponded with a positive pivot-shift sign, but was present even when that sign was not clinically detectable. Primary repair using a transosseous wire suture did not usually abolish the biomechanical abnormality. The data provide a possible explanation for the doubtful prognosis of primary repair of this ligament and encourage clinical and biomechanical evaluation of alternative procedures such as primary augmented repair

Purpose: Several studies have reported results of anterior cruciate ligament (ACL) reconstruction showing the influence of the position of the transplant. We choose the anatomic position. In order to optimise this position, we developed a navigation system using intraoperative fluoroscopic imaging. Material and methods: Thirty-five patients underwent ACL reconstruction using the computer-assisted technique. We used a fluoroscope connected to the computer equipped with an acquisition module and an image processing module which captures the lateral view of the knee provided by the fluoroscope. Surgery was performed arthroscopically. After inserting landmarks (mini-screws for the femoral end and pins for the tibial end) on the theoretically ideal positions, the computer determined the theoretical anatomic position of the tibial and femoral insertions of the ACL. The position was then validated or modified and re-validated. Postoperative radiograms (lateral view of the knee) were used to analyse the position in relation to the anatomic centre of the ACL insertion. Two groups of patients matched for sex and age were compared, 35 patients undergoing ACL reconstruction with the navigation technique versus 35 patients undergoing the same procedure without navigation. Results were compared with the nonparametric Wilcoxon test. Results: Computer-assisted positioning provided a mean difference of 5.1±1.3 mm between the centre of the transplant and the theoretical ideal point compared with 7.7±1.9 mm without assistance. Discussion: Comparison using adapted statistical tests (Wilcoxon text) demonstrated a significant difference (p=0.001) between the two groups. These findings demonstrate the improved precision and reproducibility achieved with the navigation technique. Conclusion: This technique allows the surgeon to obtain an excellent precision of the transplant insertion with excellent reproducibility. There are two drawbacks: the longer operative time (mean 15±7 minutes) and radiation exposure. But this technique is simple, easy to use and low-cost

The purpose to prospectively compare two types of tibial fixation in a series of 160 anterior cruciate ligament (ACL) reconstructions. 160 ACL reconstructions were performed on 159 patients over a period of 3 years. These patients were prospectively and randomly divided into 2 groups based on the method of tibial fixation of the ACL graft. In one group, an Intrafix system was employed and in the other, Rigidfix crosspins. All ACL reconstructions were carried out arthroscopically, in the standard way, using a quadrupled hamstring tendon graft. In all cases the hamstring grafts were harvested through a single vertical incision over the pes anserinus insertion on the proximal tibia, 2cm medial to the midline. Number 2 Ethibond whip sutures were used to prepare the graft appropriately in each group. Patients were evaluated at the 6-month and the 1-year mark, by an independent observer who was blinded to the study. The assessments consisted of manual maximum KT1000 measurements, tegner and lysholm evaluations and single leg straight and crossed over tests. The clinical results between the two groups are similar with the cross-pin method of fixation on both sides of the joint providing satisfactory stability in the ACL reconstructed knee. The hypothesis was proven and both methods of fixation were found to be clinically satisfactory in providing an acceptable degree of stability following ACL reconstruction at 1 year post-op

The use of platelet-rich plasma (PRP) as an adjuvant to tissue repair is gaining favour in orthopaedic surgery. Tunnel widening after anterior cruciate ligament (ACL) reconstruction is a recognised phenomenon that could compromise revision surgery. The purpose of this study was to determine whether PRP might prevent tunnel widening in ACL reconstruction. Patients undergoing ACL reconstruction using a hamstring graft were randomly allocated either to have PRP introduced into the tunnels peri-operatively or not. CT scanning of the knees was carried out on the day after surgery and at three months post-operatively and the width of the tunnels was measured. Patients were also evaluated clinically at three months, when laxity was also measured. Each group comprised 25 patients, and at three months post-operatively all were pain-free with stable knees, a negative Lachman test and a good range of movement. Arthrometric results had improved significantly in both groups (p < 0.001). Despite slightly less tunnel widening in the PRP group, there was no significant difference between the groups at the femoral opening or the mid-tunnel (p = 0.370 and p = 0.363, respectively) nor at the tibial opening or mid-tunnel (p = 0.333 and p = 0.177, respectively). We conclude that PRP has no significant effect in preventing tunnel widening after ACL reconstruction. Cite this article: Bone Joint J 2013;95-B:65–9

Our objectives were to establish the envelope of passive movement and to demonstrate the kinematic behaviour of the knee during standard clinical tests before and after reconstruction of the anterior cruciate ligament (ACL). An electromagnetic device was used to measure movement of the joint during surgery. Reconstruction of the ACL significantly reduced the overall envelope of tibial rotation (10° to 90° flexion), moved this envelope into external rotation from 0° to 20° flexion, and reduced the anterior position of the tibial plateau (5° to 30° flexion) (p < 0.05 for all). During the pivot-shift test in early flexion there was progressive anterior tibial subluxation with internal rotation. These subluxations reversed suddenly around a mean position of 36 ± 9° of flexion of the knee and consisted of an external tibial rotation of 13 ± 8° combined with a posterior tibial translation of 12 ± 8 mm. This abnormal movement was abolished after reconstruction of the ACL

A total of 30 patients who underwent endoscopic reconstruction of the anterior cruciate ligament using quadrupled hamstring tendons, through a single drill hole in the femur, had MRI 24 to 28 months after operation. In 18 patients the scans revealed that both the anterior and posterior portions of the graft ran in parallel from the inside of the femoral to the tibial tunnel. In 12, the posterior bundle had moved anteriorly and the anterior bundle could not be identified at the anterodistal border of the femoral tunnel. The mean difference in the anterior laxity, when compared with the contralateral knee, was 2.0 ± 1.7 mm and 4.3 ± 2.8 mm for the two types, respectively. Damage to the anterior bundle may occur when using the endoscopic technique because of biomechanical disadvantages, including concentration of loading and repetitive bending stress in the anterior bundle at the opening of the femoral tunnel

A group of 40 patients with unstable knees due to a combination of a meniscal tear with a rupture of the anterior cruciate ligament was studied to assess the effects of treatment by meniscectomy alone. The results were assessed both subjectively and objectively, but emphasis was placed on the symptoms rather than the physical signs of instability. Meniscectomy alone cured the symptoms of instability in 22 of the patients and a further eight required no further surgical treatment; bucket-handle tears were associated with a good result and posterior-horn tears with a poor result. The remaining 10 patients later underwent an additional procedure to reconstruct the ligament because of persisting symptoms. It was concluded that in patients with this combined lesion the torn meniscus should be dealt with first. In young patients with a posterior-horn tear it would be justifiable to perform a ligamentous reconstruction at the same time as the meniscectomy

We randomised 31 patients with acute tears of the anterior cruciate ligament (ACL) to receive either early (within 2 weeks) or delayed (8 to 12 weeks) reconstruction using a quadruple hamstring graft in order to determine if there was any functional advantage to early reconstruction. Outcome measures included return of knee movement, muscle dynamometry, International Knee Documentation Committee (IKDC) scores and Tegner activity levels. Two cases of symptomatic deep-venous thrombosis occurred in the early group. The mean range of movement was significantly greater at two weeks in the delayed group. Quadriceps muscle power was significantly better in the delayed group at 12 weeks (p < 0.05). These trends were evident at later time points, but were not statistically significant. One patient in each group had clinically significant knee stiffness at 52 weeks. IKDC scores and Tegner activity levels were not significantly different at 52 weeks. We conclude that there is no functional advantage to be gained by early reconstruction of the ACL

The operative treatment of lesions of the anterior cruciate ligament (ACL) in athletes has been widely advocated and performed. We have investigated the outcome of non-operative management in a lower-demand, general population. We reviewed a consecutive group of 228 patients, which excluded professional and high-level athletes, for two to 12 years after an ACL lesion had been diagnosed by arthroscopy. There was a low incidence of secondary ACL and meniscal surgery, 5.4% and 3.5% respectively, and all these procedures were performed during the first three years after the ACL injury. We studied a subgroup of 109 patients with follow-up of at least five years (mean 8.5 years) and evaluated them using the IKDC score. The general outcome was reasonably satisfactory, with 23% in grade A, 50% in grade B, 21% in grade C and only 6.4% in grade D. We found no statistically significant prognostic effect within this group as regards age, activity levels, or the incidence of associated lesions

Introduction/aims. Anterior cruciate ligament (ACL) reconstruction is now routinely performed arthroscopically. However, there are only a few centres in the UK which offer this procedure as a day case. We aimed to assess the clinical outcomes of day case ACL reconstruction using a tourniquet-less pump regulated procedure. Material/methods. A retrospective analysis of day case ACL reconstructions by a single surgeon between January 2003 and December 2010 was undertaken. All reconstructions were performed without a tourniquet, instead, haemostasis was achieved using saline – epinephrine irrigation. Outcomes were measured using Lysholm knee scores, Mohtadi index and pain scores. Results. 374 ACL reconstructions were performed on 331 patients (288 unilateral, 43 bilateral) during the study period. The average age was 31 years (range 15–58 years). All patients were followed up at regular intervals for 12 months. Lysholm knee scores improved from an average of 25 to 90. Mohtadi index scores also showed significant improvement; from an average of 22 to 90 post-operatively. All patients were pain free by 6 weeks post ACL reconstruction based on the VAP score. Complications occurred in 3% (n=11) of patients, these included DVT, wound infection and haemoarthorosis. Metal work failure occurred in 2 patients, both of whom had the EZLoc™ fixation system. Conclusions. Our experience shows that day case ACL reconstructions without the use of a tourniquet are cost effective, safe and the patients' preferred choice. Perhaps, therefore, it is time to include ACL reconstructions in the British Association of Day Case Surgery “basket” of day case procedures?

We have undertaken a randomized clinical trial comparing two methods of reconstruction of the anterior cruciate ligament in patients with chronic instability. We used an ipsilateral bone-patellar-tendon-bone autograft in 27 patients and the Ligament Advancement Reinforcement System (LARS) artificial ligament in 26. Assessment before and at two, six, 12 and 24 months after surgery, included the history, physical examination, a modified International Knee Documentation Committee (IKDC) score, the Tegner score, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and instrumented laxity testing. There were no cases of reactive synovitis or of infection of the knee, and there was no difference regarding the failure rate between the two groups. The IKDC showed no significant differences between the two groups at any stage of the follow-up. The KOOS evaluation showed consistently better results in all subscales for the LARS group during the first year of follow-up. After 24 months these differences were no longer evident. Instrument-tested laxity was greater in the LARS group at all stages of follow-up, but the differences were not significant at 24 months. Our findings suggest that at follow-up at 24 months the LARS ligament seems to be a satisfactory treatment option, especially when an early return to high levels of activity is demanded

A total of 90 patients with an isolated rupture of the anterior cruciate ligament (ACL) had a reconstruction using the ipsilateral patellar tendon secured with round-headed cannulated interference screws. Annual review for five years showed three failures of the graft (two traumatic and one atraumatic); none occurred after two years. Ten patients sustained a rupture of the contralateral ACL. At five years, 69% of those with surviving grafts continued to participate in moderate to strenuous activity. Using the International Knee Documentation Committee assessment, 90% reported their knee as being normal or nearly normal and had a median Lysholm knee score of 96 (64 to 100). Most patients (98%) had a pivot shift of grade 0 with the remaining 2% being grade 1; 90% of the group had a Lachman test of grade 0. The incidence of subsequent meniscectomy was similar in the reconstructed joint to that in the contralateral knee. Radiological examination was normal in 63 of 65 patients. Our study supports the view that reconstruction of the ACL is a reliable technique allowing full rehabilitation of the previously injured knee. In the presence of normal menisci there is a low incidence of osteoarthritic change despite continued participation in sporting activity

In a two-centre study, 164 patients with unilateral instability of the anterior cruciate ligament were prospectively randomised to arthroscopic reconstruction with either a patellar tendon graft using interference screw fixation or a quadruple semitendinosus graft using an endobutton fixation technique. The same postoperative rehabilitation protocol was used for all patients and follow-up at a median of 31 months (24 to 59) was carried out by independent observers. Four patients (2%) were lost to follow-up. No significant differences were found between the groups regarding the Stryker laxity test, one-leg hop test, Tegner activity level, Lysholm score, patellofemoral pain score, International Knee Documentation Committee (IKDC) score or visual analogue scale, reflecting patient satisfaction and knee function. Slightly decreased extension, compared with the non-operated side, was found in the patellar tendon group (p < 0.05). Patients with associated meniscal injuries had lower IKDC, visual analogue (p < 0.01) and Lysholm scores (p < 0.05) than those without such injuries. Patients in whom reconstruction had been carried out less than five months after the injury had better final IKDC scores than the more chronic cases (p < 0.05). We conclude that patellar tendon and quadruple semitendinous tendon grafts have similar outcomes in the medium term. Associated meniscal pathology significantly affects the final outcome and early reconstruction seems to be beneficial

Evidence suggests that anterior cruciate ligament (ACL) injured individuals do not use the same movement strategies as healthy individuals. It is unknown how this may affect them in more challenging activities of daily living and sport. The aim of this study is to evaluate how ACL injured patients perform a single leg squat (SLS) compared to healthy controls. SLS was evaluated as it is more challenging than gait and therefore more relevant to clinical decision making about progressing to sporting maneuvers. To date, 6 ACL deficient (ACLD) (5 males, 1 female; mass=88±22 kg; height=1.78±0.11 m; age=35±11 years), 5 ACL reconstructed (ACLR) (5 males; mass= 83±12 kg; height=1.74±0.07 m; age=29±10 years) and 5 controls (3 males, 2 females; mass= 72±13 kg; height=1.70±0.09 m; age=30±3 years) performed a SLS on the injured leg for the ACL injured participants and the dominant leg for the control group. Motion analysis was performed using a Vicon Nexus system and a Kistler force platform. Knee extension moments and angles were calculated using Vicon Nexus software. The ACLD group had reduced peak flexion angles compared to ACLR and control groups (65±5, 77±7 and 82±9 degrees respectively). Peak extension moments were similar across all groups (ACLD= 0.94±0.26 Nm/kg, ACLR=1.06±0.37 Nm/kg, control=1.04±0.36 Nm/kg). Peak knee moments occurred just after peak flexion and therefore at a smaller flexion angle for the ACLD group compared to the ACLR and control group (59±13, 75±7 and 80±6 degrees). Extension moments were similar when evaluated at a consistent angle of 50 degrees (ACLD=0.70±0.30Nm/kg, ACLR=0.63±0.34Nm/kg control=0.61±0.32Nm/kg). In this sample, the controls squatted deepest followed by the ACLR group, with the ACLD group squatting least deep. This did not translate to an identical pattern for the knee extensor moments. Performance of ACL injured individuals needs to be evaluated on more challenging tasks to fully assess recovery. Further research, with more subjects, will clarify if ACLD individuals are using a strategy to protect their knee or if others factors are preventing them from squatting deeper. This would suggest that these individuals may not have fully recovered and will not be able to perform more challenging activities

Dynamic muscle-tendon substitution for acute anterior cruciate deficiency in the dog was studied using the semimembranosus muscle-tendon. Nineteen mongrel dogs each had a semimembranosus transfer in one knee; as a control, the anterior cruciate ligament and the semimembranosus were released in the opposite knee. No postoperative immobilisation was used. The anterior drawer sign was assessed before and after operation and when the dogs were killed five months later. Dogs were excluded from the study if they developed infections or contractures of the hind legs. At five months, 11 dogs were available for study. The operated knees were examined histologically and evaluated using a reproducible index of arthritis based on: the macroscopic discoloration of the articular cartilage, the cellularity of the cartilage, the microscopic appearance of the articular surface, the loss of proteoglycans, the formation of osteophytes and the degree of subchondral osteosclerosis. There was no significant difference in the anterior drawer sign or the degree of arthritic changes between knees with a semimembranous transfer and the controls. Examination showed that a muscle-tendon transfer into the tibia was equivalent to transferring the muscle into the posterior capsule--the intra-articular tendon being weak but histologically viable. The transfer did not prevent the anterior drawer sign becoming positive nor the development of osteoarthritis. A second control group, in which three dogs had an arthrotomy and semimembranosus release in both their hind legs, showed that a semimembranosus release alone did not cause osteoarthritis

The physiological role of mechanoreceptors in the anterior cruciate ligament (ACL) was studied in unanaesthetised decerebrate-spinalised cats and dogs. Tonic activity in the quadriceps and the hamstring increased in response to physiological loading of the ACL. Evoked potentials in the posterior articular nerve (PAN) were elicited by electrical stimulation of the surface of the ligament. ACL loading also induced significant discharges from the PAN. The results suggest that ACL loading has an excitatory effect on the thigh muscles through a multimotor neurone output, and that the PAN is one of the afferent routes from the mechanoreceptors of the ACL. The ACL-muscle reflex may therefore play a physiological role in maintaining knee kinematics

Purpose: Anterior cruciate ligament (ACL) reconstruction techniques have traditionally focused on reconstruction only of one bundle of the ACL providing good to excellent results in most cases. Biomechanical studies have shown increased anterior and rotational stability with double bundle(DB) compared to single bundle(SB) anterior cruciate ligament(ACL) reconstruction. A systematic review and meta-analysis was performed to compare double bundle and single bundle methods of anterior cruciate ligament reconstruction. Methods and results: Medline (1966 onwards), EMBASE (1980 onwards) and the Cochrane database were searched retrieving 8465 possible articles, but only 5 studies fulfilled all the inclusion criteria. To be included, the study had to be prospective, randomised or quasi-randomised, comparing DB and SB grafts inserted using an arthroscopically assisted technique and have a minimum 18 month follow-up for all patients. 358 patients, 190 SB and 168 DB were considered for statistical analysis from these five papers. Outcome measures assessed included pivot shift testing, KT1000 arthrometer testing and IKDC knee scores. Using Review Manager 4.2 for statistical analysis; for dichotomous data, odds ratios and 95% confidence intervals were calculated and for continuous data, weighted mean difference and 95% confidence intervals were calculated. Patients in the double bundle group were significantly less likely to have a positive pivot shift test (P< 0.0001). KT1000 arthrometer testing demonstrated greater antero-posterior stability with the DB group (P=0.002). There was no difference between the groups in terms of IKDC score. Conclusion: The use of a double bundle technique improved both anteroposterior and rotational stability but not the clinical IKDC score suggesting that recovery of knee stability alone is not sufficient for achieving a better outcome

Purpose: The anterior cruciate ligament (ACL) is composed of two strands, the anteromedial (AM) and the posterolateral (PL). Each strand has a distinct biomechanical role. The classical techniques for reconstruction of the ACL using a one-strand graft cannot replace the AM strand of the ligament. Control of knee laxity after graft reconstruction with a single strand cannot restore physiological laxity. Material and methods: This study was performed on 16 matched cadaver knees randomised for reconstruction technique. Anterior tibial dislocation was measured with the Rolimeter arthrometer using manual traction on the intact knee, after section of the ACL, and after arthroscopic reconstruction of the ACL using a 2-strand or 4-strand hamstring method at 20°, 60°, and 90° flexion. Changes in the length of each reconstructed strand were measured. Results: For the 16 intact knees, anterior laxity was measured at 20°, 60° and 90°. After section of the ACL, laxity increased significantly at all angles studied. Statistical parametric and non-parametric tests demonstrated a significant difference between laxity after ACL section and after ACL reconstruction (one-strand) at 20°, 60° and 90° flexion. There was a significant difference between intact ACL and reconstructed ACL at 20° flexion, the residual laxity was greater after one-strand reconstruction. Conversely, at 60° and 90°, there was no difference in anterior displacement of the tibia for intact and reconstructed ACL. There was a statistically significant improvement in laxity between sectioned and reconstructed (two-strand) ACL at 20°, 60° and 90° but no difference in anterior dislocation between the intact ACL and the reconstructed ACL at 2°, 60°, and 90° flexion. Conclusion: Two-strand reconstruction of the ACL provides laxity comparable with that of the intact ACL at 20°, 60°, and 90° flexion while one-strand reconstruction only re-establishes physiological laxity at 60° and 90°