Epidemiology and distribution of cruciate ligament injuries in children and adolescents, with an analysis of risk factors for concomitant meniscal tear

Introduction

To investigate the epidemiological features and prevalence of cruciate ligament injuries (CLI) in children and adolescents, and to examine the potential risk factors associated with concomitant meniscal tear (MT) among this population.

Methods

The demographic data and injury details of children and adolescents with CLI from Southeast China were analyzed to describe their distribution characteristics, alongside an analysis of the prevalence of MTs, the most frequent complication. In addition, binary logistic analysis was employed to ascertain the risk factors linked to MT in individuals suffering from CLI.

Results

A total of 203 patients with CLI (n = 206) met the inclusion criteria, with a male-to-female ratio of 2.3:1. Notably, a higher proportion of females were aged ≤16 years old compared to males, who predominated in patients aged >16 years (P = 0.001). Among children and adolescents, anterior cruciate ligament (ACL) injuries were the primary type of CLI, accounting for 88.18% (179/203) of all cases. The majority of cases (132/203, 65.02%) were sustained during sports activities, and sprains were the predominant mechanism of injury (176/203, 86.7%). Additionally, the most common associated injury was an MT (157/203, 77.34%). The posterior horn is the most frequently affected site for both medial MT (62.93% out of 73 cases) and lateral MT (70.19% out of 73 cases). Moreover, vertical tears constituted the majority of medial MTs (59.48% out of 116 cases). Furthermore, patients with a higher BMI faced an increased risk of associated MT in comparison to non-overweight patients (88% vs. 73.86%; P = 0.038). Each increase in BMI unit was linked with a 14% higher probability of associated MT occurrence in children and adolescents with CLI (OR = 1.140; P = 0.036).

Discussion

ACL injuries are a common form of knee ligament injury among children and adolescents, especially those over the age of 16, and are often the result of a sprain. Meniscal posterior horn injury is the most commonly associated injury of youth with CLI. Additionally, overweight or obese people with CLI are at a greater risk of developing MT.

TTA-Rapid for treating the canine cruciate deficient stifle: Medium to long-term outcome and analysis of risk factors

BACKGROUND

This study aimed to evaluate medium to long-term outcomes following treatment of lameness associated with cranial cruciate ligament insufficiency using the tibial tuberosity advancement (TTA)-Rapid technique and to investigate risk factors associated with outcome, including tibial plateau angle (TPA).

METHODS

Patient records for cases treated over an 80-month period were examined retrospectively. An owner postal questionnaire using a clinical metrology instrument (Liverpool Osteoarthritis in Dogs) evaluated the outcome at least 6 months after surgery.

RESULTS

A total of 149 procedures were carried out in 120 dogs. Questionnaires were received for 64 dogs (53.3%), with a median follow-up time of 37.5 months. Outcome was judged to be satisfactory, based on frequency of lameness, in 63 (98.4%), while satisfactory outcomes were achieved in 61 (95.3%) based on severity of lameness and in 50 (78.1%) based on mobility score. Statistical analysis showed that age, bodyweight, TPA, meniscal injury and concurrent patellar surgery did not influence outcome, but time to follow-up positively correlated with mobility score.

LIMITATIONS

This study involved one surgeon in one centre with outcome data based on the completion of an owner questionnaire, although this used a validated clinical metrology instrument.

CONCLUSION

TTA-Rapid offers a treatment option for cranial cruciate-deficient stifles with a good medium to long-term outcome, and no risk factors were identified to suggest any limitations to its use.

Injury risk functions for the four primary knee ligaments

The purpose of this study was to develop injury risk functions (IRFs) for the anterior and posterior cruciate ligaments (ACL and PCL, respectively) and the medial and lateral collateral ligaments (MCL and LCL, respectively) in the knee joint. The IRFs were based on post-mortem human subjects (PMHSs). Available specimen-specific failure strains were supplemented with statistically generated failure strains (virtual values) to accommodate for unprovided detailed experimental data in the literature. The virtual values were derived from the reported mean and standard deviation in the experimental studies. All virtual and specimen-specific values were thereafter categorized into groups of static and dynamic rates, respectively, and tested for the best fitting theoretical distribution to derive a ligament-specific IRF. A total of 10 IRFs were derived (three for ACL, two for PCL, two for MCL, and three for LCL). ACL, MCL, and LCL received IRFs in both dynamic and static tensile rates, while a sufficient dataset was achieved only for dynamic rates of the PCL. The log-logistic and Weibull distributions had the best fit (p-values: >0.9, RMSE: 2.3%-4.7%) to the empirical datasets for all the ligaments. These IRFs are, to the best of the authors' knowledge, the first attempt to generate injury prediction tools based on PMHS data for the four knee ligaments. The study has summarized all the relevant literature on PHMS experimental tensile tests on the knee ligaments and utilized the available empirical data to create the IRFs. Future improvements require upcoming experiments to provide comparable testing and strain measurements. Furthermore, emphasis on a clear definition of failure and transparent reporting of each specimen-specific result is necessary.

An Atlas of the Knee Joint Proteins and Their Role in Osteoarthritis Defined by Literature Mining

Osteoarthritis (OA) is the most prevalent rheumatic pathology. However, OA is not simply a process of wear and tear affecting articular cartilage but rather a disease of the entire joint. One of the most common locations of OA is the knee. Knee tissues have been studied using molecular strategies, generating a large amount of complex data. As one of the goals of the Rheumatic and Autoimmune Diseases initiative of the Human Proteome Project, we applied a text-mining strategy to publicly available literature to collect relevant information and generate a systematically organized overview of the proteins most closely related to the different knee components. To this end, the PubPular literature-mining software was employed to identify protein-topic relationships and extract the most frequently cited proteins associated with the different knee joint components and OA. The text-mining approach searched over eight million articles in PubMed up to November 2022. Proteins associated with the six most representative knee components (articular cartilage, subchondral bone, synovial membrane, synovial fluid, meniscus, and cruciate ligament) were retrieved and ranked by their relevance to the tissue and OA. Gene ontology analyses showed the biological functions of these proteins. This study provided a systematic and prioritized description of knee-component proteins most frequently cited as associated with OA. The study also explored the relationship of these proteins to OA and identified the processes most relevant to proper knee function and OA pathophysiology.

Knee ligament injuries in U.S. pedestrian crashes

OBJECTIVE

Projectile legform tests are used to evaluate pedestrian lower extremity injury risk, including risk of injury to the cruciate and collateral ligaments. However, it has been suggested that cruciate ligament injuries rarely occur without collateral ligament injuries, making a cruciate ligament injury requirement unnecessary in pedestrian test procedures. Therefore, the current study examines cruciate ligament injuries among U.S. pedestrians with and without other injuries that are evaluated in pedestrian test procedures.

METHODS

Injury data for pedestrians treated in U.S. trauma centers from 2007 to 2017 were drawn from the National Trauma Data Bank (NTDB) Research Data Set (RDS) and from its successor, the Trauma Quality Program (TQP) Participant User Files (PUF). Crash and demographic details for individual cases with documented knee ligament injuries were obtained from the Pedestrian Crash Data Study (PCDS).

RESULTS

Among pedestrians aged 16 and older with knee ligament injuries, 38% had only collateral injuries, 31% had only cruciate injuries and 31% were documented with injuries to both. Younger pedestrians also sustained cruciate injuries without collateral injuries, with 36% of the 0-15 year-old pedestrians diagnosed with knee ligament injuries having isolated cruciate injuries. Given that injuries to the left and right knee could not be distinguished in NTDB cases, these estimates of isolated ligament injuries are likely conservative, so that at least 31% of pedestrians aged 16 and older and at least 36% of younger pedestrians sustained cruciate ligament injuries without collateral ligament injuries in the same knee. A PCDS case study illustrated how cruciate injury can occur without collateral injury in a lateral bumper impact below the knee.

CONCLUSIONS

Cruciate ligament injuries can occur in pedestrian crashes, with or without other injuries that are evaluated in pedestrian test procedures. Isolated cruciate injuries may be more likely in impacts above or below the knee and in impacts with a component of anterior-posterior loading. The frequency of cruciate injury in the absence of collateral injury in lateral and non-lateral impact supports inclusion of injury measures correlating to cruciate injury risk in pedestrian legform test procedures.

Computational analysis of tibial slope adjustment with fixed-bearing medial unicompartmental knee arthroplasty in ACL- and PCL-deficient models

AIMS

A functional anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) has been assumed to be required for patients undergoing unicompartmental knee arthroplasty (UKA). However, this assumption has not been thoroughly tested. Therefore, this study aimed to assess the biomechanical effects exerted by cruciate ligament-deficient knees with medial UKAs regarding different posterior tibial slopes.

METHODS

ACL- or PCL-deficient models with posterior tibial slopes of 1°, 3°, 5°, 7°, and 9° were developed and compared to intact models. The kinematics and contact stresses on the tibiofemoral joint were evaluated under gait cycle loading conditions.

RESULTS

Anterior translation increased in ACL-deficient UKA cases compared with intact models. In contrast, posterior translation increased in PCL-deficient UKA cases compared with intact models. As the posterior tibial slope increased, anterior translation of ACL-deficient UKA increased significantly in the stance phase, and posterior translation of PCL-deficient UKA increased significantly in the swing phase. Furthermore, as the posterior tibial slope increased, contact stress on the other compartment increased in cruciate ligament-deficient UKAs compared with intact UKAs.

CONCLUSION

Fixed-bearing medial UKA is a viable treatment option for patients with cruciate ligament deficiency, providing a less invasive procedure and allowing patient-specific kinematics to adjust posterior tibial slope. Patient selection is important, and while AP kinematics can be compensated for by posterior tibial slope adjustment, rotational stability is a prerequisite for this approach. ACL- or PCL-deficient UKA that adjusts the posterior tibial slope might be an alternative treatment option for a skilled surgeon. Cite this article: Bone Joint Res 2022;11(7):494-502.

The Efficacy and Outcome of a Two-Staged Operation for Irreducible Knee Dislocation: A Prospective Short-Term Follow-Up

Background: Irreducible knee dislocation (IKD) is a very rare but serious type of knee dislocation; it can lead to soft tissue necrosis due to incarceration of the medial structures and faces great difficulty in the postoperative rehabilitation, too. IKD needs careful pre-operative planning. There is no universal agreement about the appropriate surgical strategy for IKD. The purpose of this study was to investigate the clinical efficacy, safety, and outcome of the two-staged operation in treatment of IKD. Methods: IKD patients were included from June 1, 2016 to May 31, 2020. In the stage-1 surgery, acute reduction and extra-articular structure repair were performed. Following an intermediate rehabilitation, delayed cruciate ligament reconstructions were performed in stage-2. Physical examination, CT, MRI, and X-ray were performed during the pre-operative period. Knee function, joint stability, ligament laxity, knee range of motion (ROM), and alignment were accessed at follow-ups. The minimum and maximum follow-up times were 0.5 years and 1 year, respectively. Results: In total, 17 IKD patients were included. There were three subjects (17.65%) missing at the 1 year follow-up and the average follow-up was 11.18 ± 2.53 months. After stage-1, normal alignment and superior valgus/varus stability were restored in most subjects; however, a notable anterior-posterior instability still existed in most patients. The intermediate rehabilitation processed smoothly (6.94 ± 1.20 weeks), and all patients achieved knee ROM of 0-120° finally. At 0.5 years and 1 year follow-up after stage-2, all subjects had achieved normal knee stability, ROM, and satisfying joint function. No infection or DVT was observed. Conclusions: The two-staged operation for IKD has superior efficacy on knee stability and function, and it can facilitate the rehabilitation and achieve satisfactory short-term outcome.

Minispheroids as a Tool for Ligament Tissue Engineering: Do the Self-Assembly Techniques and Spheroid Dimensions Influence the Cruciate Ligamentocyte Phenotype?

Spheroid culture might stabilize the ligamentocyte phenotype. Therefore, the phenotype of lapine cruciate ligamentocyte (L-CLs) minispheroids prepared either by hanging drop (HD) method or by using a novel spheroid plate (SP) and the option of methyl cellulose (MC) for tuning spheroid formation was tested. A total of 250 and 1000 L-CLs per spheroid were seeded as HDs or on an SP before performing cell viability assay, morphometry, gene expression (qRT-PCR) and protein immunolocalization after 7 (HD/SP) and 14 (SP) days. Stable and viable spheroids of both sizes could be produced with both methods, but more rapidly with SP. MC accelerated the formation of round spheroids (HD). Their circular areas decreased significantly during culturing. After 7 days, the diameters of HD-derived spheroids were significantly larger compared to those harvested from the SP, with a tendency of lower circularity suggesting an ellipsoid shape. Gene expression of decorin increased significantly after 7 days (HD, similar trend in SP), tenascin C tended to increase after 7 (HD/SP) and 14 days (SP), whereas collagen type 1 decreased (HD/SP) compared to the monolayer control. The cruciate ligament extracellular matrix components could be localized in all mini-spheroids, confirming their conserved expression profile and their suitability for ligament tissue engineering.

Comparison of Bone-Patellar Tendon-Bone Graft, Semitendinosus-Gracilis Graft and Semitendinosus-Gracilis with Preserved Tibial Insertion Graft in Anterior Cruciate Ligament Reconstruction in Sports Persons

Introduction

Bone-patellar tendon-bone (BPTB) and semitendinosus-gracilis (STG) are the commonest grafts used for ACL reconstruction. However even after having been debated for years, there is no consensus about the ideal graft. Moreover, the literature is deficient about STG graft with preserved tibial insertion (STGPI) which preserves the proprioception. Our aim is to compare the outcome of BPTB, free STG and STGPI grafts after ACL reconstruction in professional sports persons. We compared the outcome in terms of mechanical stability, functional outcome, return to sports activity and degenerative changes.

Material and Methods

Professional sports persons aged between 16-50 years operated for ACL tear using BPTB, free STG and STGPI grafts with minimum follow-up of two years were identified from hospital records. Patients with associated knee injuries were excluded. Patients, divided in three groups according to graft used, were compared in terms of mechanical stability (arthrometric examination KT-1000 score), functional outcome (Lysholm Score), return to sports activity (Tegner score and difference in thigh circumference) and degenerative changes (KL grading).

Results

BPTB graft group was found to be better than free STG and STGPI graft groups in terms of KT-1000 score. There was no statistically significant difference among the groups in terms of Lysholm score, Tegner score, difference in thigh circumference and KL grading.

Conclusion

BPTB graft is better than free STG and STGPI grafts in terms of knee stability. When compared for patient reported outcome, return to sports activity, osteoarthritic changes and graft failure there is no significant difference among the three types of grafts.

Biologically Enhanced Genome-Wide Association Study Provides Further Evidence for Candidate Loci and Discovers Novel Loci That Influence Risk of Anterior Cruciate Ligament Rupture in a Dog Model

Anterior cruciate ligament (ACL) rupture is a common condition that disproportionately affects young people, 50% of whom will develop knee osteoarthritis (OA) within 10 years of rupture. ACL rupture exhibits both hereditary and environmental risk factors, but the genetic basis of the disease remains unexplained. Spontaneous ACL rupture in the dog has a similar disease presentation and progression, making it a valuable genomic model for ACL rupture. We leveraged the dog model with Bayesian mixture model (BMM) analysis (BayesRC) to identify novel and relevant genetic variants associated with ACL rupture. We performed RNA sequencing of ACL and synovial tissue and assigned single nucleotide polymorphisms (SNPs) within differentially expressed genes to biological prior classes. SNPs with the largest effects were on chromosomes 3, 5, 7, 9, and 24. Selection signature analysis identified several regions under selection in ACL rupture cases compared to controls. These selection signatures overlapped with genome-wide associations with ACL rupture as well as morphological traits. Notable findings include differentially expressed ACSF3 with MC1R (coat color) and an association on chromosome 7 that overlaps the boundaries of SMAD2 (weight and body size). Smaller effect associations were within or near genes associated with regulation of the actin cytoskeleton and the extracellular matrix, including several collagen genes. The results of the current analysis are consistent with previous work published by our laboratory and others, and also highlight new genes in biological pathways that have not previously been associated with ACL rupture. The genetic associations identified in this study mirror those found in human beings, which lays the groundwork for development of disease-modifying therapies for both species.

The Finnish Canine Stifle Index: responsiveness to change and intertester reliability

Background

The responsiveness and the intertester reliability of the Finnish Canine Stifle Index (FCSI) were tested, and a cut-off between compromised and severely compromised performance level was set.

Methods

Three groups of dogs were used, 29 with any stifle dysfunction (STIF), 17 with other musculoskeletal disease except stifle (OTHER) and 11 controls (CTRL). All dogs were tested with the FCSI by the same physiotherapist at three occasions, at baseline, at six weeks and 10 weeks, and once also by another physiotherapist.

Results

Dogs in the STIF group demonstrated significantly higher (P<0.001) FCSI scores than in OTHER or CTRL groups at baseline. Only the STIF group showed a significant (P<0.001) change in FCSI score at all time points, indicating responsiveness to change. There were no significant differences between the evaluators (P=0.736), showing good intertester reliability, supported by moderate to good (0.78) intraclass correlation coefficient (ICC). The evaluator performing the FCSI did not have a significant effect when comparing the groups of dogs (P=0.214). The 95 per cent confidence intervals of the ICC per group were 0.79 (0.60, 0.91) for STIF, 0.83 (0.53, 0.96) for OTHER 0.78 (0.64, 0.88) for all dogs. A cut-off differentiating a severely compromised from a compromised performance was set at 120, having sensitivity of 83 per cent and specificity of 89 per cent.

Conclusion

The FCSI is a recommendable measure of dogs’ stifle functionality.

Rates of Adverse Outcomes and Revision Surgery After Anterior Cruciate Ligament Reconstruction: A Study of 104,255 Procedures Using the National Hospital Episode Statistics Database for England, UK

BACKGROUND

After an anterior cruciate ligament (ACL) injury, ACL reconstruction is an elective procedure, and therefore, an understanding of the attributable risk from undergoing ACL reconstruction is necessary for patients to make a fully informed treatment decision.

PURPOSE

To determine the absolute risk of adverse outcomes including reoperation after ACL reconstruction with comparison, where possible, to the rate of adverse events reported in the general population.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

National hospital data on all ACL reconstructions performed in England between April 1, 1997, and March 31, 2017, were analyzed. Revision cases, bilateral procedures within 6 months, and cases with concurrent cartilage or multiple ligament surgery were excluded. The primary outcome was the occurrence of at least 1 serious complication (myocardial infarction, stroke, pulmonary embolism, infection requiring surgery, fasciotomy, neurovascular injury, or death) within 90 days. Additionally, 5-year rates of revision ACL reconstruction, contralateral ACL reconstruction, and meniscal surgery were investigated.

RESULTS

There were 133,270 ACL reconstructions performed, of which 104,255 were eligible for analysis. Within 90 days, serious complications occurred in 675 (0.65% [95% CI, 0.60-0.70]), including 494 reoperations for infections (0.47% [95% CI, 0.43-0.52]) and 129 for pulmonary embolism (0.12% [95% CI, 0.10-0.15]). Of 54,275 procedures with at least 5 years' follow-up, 1746 (3.22% [95% CI, 3.07-3.37]) underwent revision ACL reconstruction in the same knee, 1553 underwent contralateral ACL reconstruction (2.86% [95% CI, 2.72-3.01]), and 340 underwent meniscal surgery (0.63% [95% CI, 0.56-0.70]). The overall risk of serious complications fell over time (adjusted odds ratio [OR], 0.96 per year [95% CI, 0.95-0.98]); however, older patients (adjusted OR, 1.11 per 5 years [95% CI, 1.07-1.16]) and patients with a greater modified Charlson Comorbidity Index (adjusted OR, 2.41 per 10 units [95% CI, 1.65-3.51]) were at a higher risk. For every 850 (95% CI, 720-1039) ACL reconstructions, 1 pulmonary embolism could be provoked. For every 213 (95% CI, 195-233), 1 native knee joint infection could be provoked.

CONCLUSION

The overall risk of adverse events after ACL reconstruction is low; however, some rare but serious complications, including infections or pulmonary embolism, may occur. Around 3% of patients undergo further ipsilateral or contralateral ACL reconstruction within 5 years. These data will inform shared decision making between clinicians and patients considering their treatment options.

A Nationwide Follow-up Survey on the Effectiveness of an Implemented Neuromuscular Training Program to Reduce Acute Knee Injuries in Soccer Players

Background:

A cruciate ligament (CL) injury is a severe injury in soccer. Neuromuscular training programs have a well-documented preventive effect, but there are few studies on the effectiveness of such a program at a national level. The Swedish Knee Control Program (KCP) was found to be effective in preventing CL injuries in youth female soccer players. The KCP was implemented nationwide in Sweden in 2010.

Purpose:

To evaluate the effectiveness of the Swedish KCP in reducing acute knee injuries in soccer players at a nationwide level.

Study Design:

Descriptive epidemiology study.

Methods:

All licensed soccer players in Sweden are covered by the same insurance company. Using this insurance database, around 17,500 acute knee injuries that were reported to the insurance company between 2006 and 2015 were included in the study. By matching the number of licensed soccer players with the number of reported injuries each year, the annual incidence of knee and CL injuries was able to be calculated. To evaluate the spread of the KCP nationally, a questionnaire was sent to all 24 Swedish district football associations (FAs) with questions regarding KCP education. The number of downloads of the KCP mobile application (app) was obtained.

Results:

The incidence of CL injuries decreased during the study period for both male (from 2.9 to 2.4 per 1000 player-years) and female players (from 4.9 to 3.9 per 1000 player-years). The overall incidence of knee injuries decreased in both male (from 5.6 to 4.6 per 1000 player-years) and female players (from 8.7 to 6.4 per 1000 player-years). Comparing before and after the nationwide implementation of the KCP, there was a decrease in the incidence of CL injuries by 6% (rate ratio [RR], 0.94 [95% CI, 0.89-0.98]) in male players and 13% (RR, 0.87 [95% CI, 0.81-0.92]) in female players and a decrease in the incidence of knee injuries by 8% (RR, 0.92 [95% CI, 0.89-0.96]) and 21% (RR, 0.79 [95% CI, 0.75-0.83]), respectively (P < .01 for all). This trend corresponded to a reduction of approximately 100 CL injuries each year in Sweden. A total of 21 of 24 district FAs held organized KCP educational courses during the study period. The percentage of district FAs holding KCP courses was between 46% and 79% each year. There were 101,236 downloads of the KCP app.

Conclusion:

The KCP can be considered partially implemented nationwide, and the incidence of knee and CL injuries has decreased in both sexes at a nationwide level.

Developing a testing battery for measuring dogs' stifle functionality: the Finnish Canine Stifle Index (FCSI)

This study aimed at developing a quantitative testing battery for dogs’ stifle functionality, as, unlike in human medicine, currently none is available in the veterinary field. Forty-three dogs with surgically treated unilateral cranial cruciate ligament rupture and 21 dogs with no known musculoskeletal problems were included. Eight previously studied tests: compensation in sitting and lying positions, symmetry of thrust in hindlimbs when rising from lying and sitting, static weight bearing, stifle flexion and extension and muscle mass symmetry, were summed into the Finnish Canine Stifle Index (FCSI). Sensitivities and specificities of the dichotomised FCSI score were calculated against orthopaedic examination, radiological and force platform analysis and a conclusive assessment (combination of previous). One-way analysis of variance (ANOVA)was used to evaluate FCSI score differences between the groups. Cronbach’s alpha for internal consistency was calculated. The range of the index score was 0–263, with a proposed cut-off value of 60 between ‘adequate’ and ‘compromised’ functional performance. In comparison to the conclusive assessment, the sensitivity and specificity of the FCSI were 90 per cent and 90.5 per cent, respectively. Cronbach’s alpha for internal reliability of the FCSI score was 0.727. An estimate of the surgically treated and control dogs’ FCSI scores were 105 (95 per cent CI 93 to 116) and 20 (95 per cent CI 4 to 37), respectively. The difference between the groups was significant (P<0.001).

Knee Osteoarthritis after Reconstruction of Isolated Anterior Cruciate Ligament Injuries: A Systematic Literature Review

Purpose  The aim of this review was to analyze the current literature on osteoarthritic evolution of knees without any combined meniscal or ligament lesions undergoing anterior cruciate ligament (ACL) reconstruction.

Methods  A PubMed/MEDLINE research was performed using the following keywords: “Anterior Cruciate Ligament Reconstruction” [Mesh] AND “Osteoarthritis, Knee” [Mesh]. Only English language literature and articles published after 2005 were included. Studies including concomitant meniscal tears, posterior cruciate or collateral ligament injuries, previous surgery in the affected knees, infections, osteochondral defects, loose bodies, synovial plica syndrome, and posteromedial or posterolateral corner injuries were not considered in this review.

Results  Twelve studies were selected. These papers included 892 patients (mean age at the time of surgery was 22.3 years), with an average follow-up of 11 years. Imaging at follow-up was obtained with standard radiographs in nine studies, magnetic resonance imaging (MRI) in one study, and both X-rays and MRI in two studies. Eight studies reported osteoarthritic evolution, with different prevalence.

Conclusion  Only few high-quality studies focused on these specific patients have been published. When reconstructed, isolated ACL-deficient knees have a low risk of osteoarthritic evolution, but mild signs of joint degeneration are reported by the current literature.

Level of Evidence  Level IV, systematic review of level I to level IV studies.

Reduction of atlantoaxial dislocation prevented by pathological position of the transverse ligament in fixed, irreducible os odontoideum: operative illustrations and radiographic correlates in 41 patients

OBJECTIVE Os odontoideum (OO) is a craniovertebral junction (CVJ) abnormality in which an ossicle (small bone) is cranial to a hypoplastic dens by a variable gap. This abnormality can result in instability, which may be reducible or irreducible. What leads to irreducibility in OO is unclear. Therefore, the authors sought to better understand the causes of irreducibility in OO. METHODS A retrospective review was conducted, which identified more than 200 patients who had undergone surgical treatment for OO between 1978 and 2015 at the University of Iowa Hospitals and Clinics. Only the 41 patients who had irreducible OO were included in this study. All inpatient and outpatient records were retrospectively reviewed, and patient demographics, clinical presentation, radiographic findings, surgical treatment, and operative findings were recorded and analyzed. RESULTS The cohort of 41 patients who were found to have irreducible OO included both children and adults. A majority of patients were adults (61% were 18 years or older). Clinical presentation included neck pain and headache in the majority of patients (93%). Weakness, sensory disturbances, and myelopathy were invariably present in all 41 patients (100%). Down syndrome was much more common in the pediatric cohort than in the adult cohort; of the 16 pediatric patients, 6 had Down syndrome (38%), and none of the adults did. Of the 16 pediatric patients, 5 had segmentation failure (31%) in the subaxial spine, and none of the adults did. A form of atlantoaxial dislocation was seen in all cases. On CT imaging, atlantoaxial facets were dislocated in all 41 cases but did not have osseous changes that would have prevented reduction. On MRI, the transverse ligament was identified anterior and inferior to the ossicle and superior to the hypoplastic odontoid process in all cases in which these studies were available (i.e., post-MRI era; 36 of 36 cases). The ligament was hypointense on T2-weighted images but also had an associated hyperintense signal on T2 images. Intraoperatively, the transverse ligament was identified anterior and inferior to the ossicle and superior to the hypoplastic odontoid process in all 41 cases. CONCLUSIONS In the largest series to date of irreducible OO and the only study to examine variable factors that lead to irreducibility in OO, the authors found that the position of the transverse ligament anterior and inferior to the ossicle is the most common factor in the irreducibility of OO. The presence of granulation tissue and of the dystopic variant of OO is also associated with irreducibility. The presence of Down syndrome and segmentation failure probably leads to faster progression of ligamentous incompetence and therefore earlier presentation of instability and irreducibility. This is the first study in which intraoperative findings regarding the transverse ligament have been correlated with MRI.

Comparison of Outcomes of Two Femoral Fixation Devices in Hamstring Anterior Cruciate Ligament Reconstruction

BACKGROUND

Tear of the anterior cruciate ligament (ACL) is a common ligamentous injury of the knee. Reconstruction of this ligament is often required to restore functional stability of the knee. Outcome of ACL reconstruction is significantly affected by how the graft is fixed to the bone. This study is to determine if there is a different clinical outcome after cortical versus cortical-cancellous suspension femoral fixation in hamstring based anterior cruciate ligament (ACL) reconstruction.

MATERIALS AND METHODS

This is a retrospective comparative study conducted between 2006 and 2010. We enrolled patients who underwent arthroscopic ACL reconstruction. Sixty two patients met inclusion criteria and 41 agreed to come for followup assessment. Median age was of 28 years (range 18-39 years). Demographic baseline profile of both groups was similar. The femoral fixation devices were cortical (n = 16) and cortical-cancellous suspension techniques (n = 25). The average period of evolution at the time of assessment was 40 months (range 12-72 months). The patients were examined according to Lachman test (using Rolimeter knee tester), anterior drawer test, pivot shift test, International Knee Documentation Committee questionnaire, and Tegner-Lysholm knee scoring scale.

RESULTS

The objective evaluation of the patients (Lachman test) showed better results in terms of stability in the group of patients who underwent the cortical-cancellous suspension method. These differences were not reflected in the assessment of activity level (Tegner-Lysholm), where both groups showed the same results.

CONCLUSIONS

ACL reconstruction with both cortical and cortical-cancellous suspension femoral fixation techniques show the same clinical results at medium long followup. However, cortical-cancellous fixations seem to provide greater stability to the reconstruction.

A Case of 3-month-old Neglected Elbow Dislocation Managed by Open Reduction and Cruciate Ligament Reconstruction Using Tendon Graft

INTRODUCTION

Old neglected posterior type of elbow dislocations is not very common and generally requires open reduction. It was usually treated with open reduction and K-wire stabilization. We did a newer method in which in addition cruciate type ligament reconstruction; we have reconstructed lateral ulnar collateral ligament (LUCL) and UCL (medial collateral ligament) using semitendinosus graft. This allowed extra stability and early mobilization of the elbow joint. Authors report 3-month-old neglected posterior type of elbow dislocation without any fracture.

CASE REPORT

A 42-year-old male presented with pain and tenderness with deformity of the left elbow joint and inability to move the elbow joint after he fell down since 3 months. There was no neurovascular deficit. Radiological examination confirmed posterior dislocation of elbow joint without any fracture. The patient is managed by open reduction and cruciate ligament reconstruction of elbow joint using autologous semitendinosus graft.

CONCLUSION

Open reduction with cruciate ligament reconstruction provides excellent stability for early mobilization of old neglected elbow dislocation.

Magnetic Resonance Imaging of the Craniovertebral Junction Ligaments: Normal Anatomy and Traumatic Injury

The superb stability and flexibility of the craniovertebral junction (CVJ) are enabled by the ligaments that connect the occipital bone and the C1 and C2 vertebral bodies. Radiographically, these ligaments are best assessed with magnetic resonance imaging (MRI), which has excellent soft tissue contrast, but typically poor spatial resolution. With the advent of advanced MRI techniques, including volumetric sequences, high spatial resolution and contrast resolution can both be attained, allowing for detailed analysis of the ligaments, particularly in trauma settings. We have instituted a cervical spine trauma protocol which utilizes a high resolution (1-mm voxel) volumetric proton density sequence to detect injuries to the ligaments of the CVJ in all trauma patients who receive a cervical spine MRI in our emergency room. In this article, we review techniques for imaging the ligaments at the CVJ, the normal imaging anatomy and the function of the CVJ ligaments, and their appearance in cases of traumatic injury.

Partial tears of anterior cruciate ligament: Results of single bundle augmentation

BACKGROUND

Partial tears of the anterior cruciate ligament (ACL) are common and usually present with symptomatic instability. The remnant fibers are usually removed and a traditional ACL reconstruction is done. But with increased understanding of ACL double bundle anatomy, the remnant tissue preservation along with a single bundle augmentation of the torn bundle is also suggested. The purpose of this study was to evaluate the results of selective anatomic augmentation of symptomatic partial ACL tears. Our hypothesis is that this selective augmentation of partial ACL tears could restore knee stability and function.

MATERIALS AND METHODS

Consecutive cases of 314 ACL reconstructions, 40 patients had intact ACL fibers in the location corresponding to the anteromedial (AM) or posterolateral (PL) bundle and were diagnosed as partial ACL tears perioperatively. All patients underwent selective augmentation of the torn bundle, while keeping the remaining fibers intact using autogenous hamstring graft. A total of 38 patients (28 males, 10 females) were available with a minimum of 3 years followup. 26 cases had AM bundle tears and 12 cases had PL bundle tears respectively. Patients were assessed with International Knee Documentation Committee (IKDC) 2000 Knee Evaluation Form, Lysholm score; instrumented knee testing was performed with the arthrometer (KT 2000). Statistical analysis was performed to compare the preoperative and postoperative objective evaluation.

RESULTS

At 3 years followup, 31.6% patients were graded A, 65.8% were graded B and 2.6% was graded C at IKDC objective evaluation. Manual laxity tests, Lysholm's score, mean side to side instrumental laxity and Tegner activity score improved significantly. 76% patients returned to preinjury level of sports activity after augmentation.

CONCLUSION

The results of anatomic single bundle augmentation in partial ACL tears are encouraging with excellent improvement in functional scores, side to side laxity and return to sports activity.

Displaced avulsion fractures of the posterior cruciate ligament: Treated by stellate steel plate fixation

BACKGROUND

The open reduction with internal fixation is an effective approach for treatment of avulsion fracture of posterior cruciate ligament. The previously used internal fixation materials including hollow screws, absorbable screw, tension bands and sutures have great defects such as insufficient fixation strength, susceptibility to re-fracture, etc. Stellate steel plate is novel material for internal fixation which has unique gear-like structure design. We used stellate steel plate for treatment of displaced avulsion fractures of posterior cruciate ligament in this study.

MATERIALS AND METHODS

14 patients (9 men, 5 women; aged, 19-35 years; mean age, 28 years) with displaced avulsion fractures of the tibial insertion of the posterior cruciate ligament were retrospectively analyzed between June 2009 and June 2011. The mean duration from injury to the operation was 8.3 days (range 6-15 days). All the patients were treated with open reduction and internal fixation of a stellate steel plate (DePuy, Raynham, MA 02767, USA). The Lysholm-Tegner knee function score criteria were used to analyze results.

RESULTS

The mean followup was 24.6 months (range 18-32 months). After 6 months, all the fractures healed and knee joint activity was normal, with no knee stiffness or instability. The Lysholm-Tegner scores were 97.1 ± 1.7 points at the final followup.

CONCLUSION

Owing to its unique gear structure, the stellate steel plate design can effectively fix an avulsion fracture block and it is a simple operation with short postoperative rehabilitation time and firm fixation.

Gene signature of the embryonic meniscus

The meniscus is a fibrocartilagenous disc in the knee that protects the joint from damage. Meniscal injuries are common, however repair efforts are largely unsuccessful and are not able to prevent the degenerative changes that result in development of osteoarthritis. Tissue regeneration in adults often recapitulates events of embryonic development, suggesting the regulatory pathways controlling morphogenesis are candidate repair signals. Here we use laser capture microdissection to collect mouse embryonic day 16 (E16) meniscus, articular cartilage, and cruciate ligaments. RNA isolated from these tissues was then used to perform genome-wide microarray analysis. We found 38 genes were differentially expressed between E16 meniscus and articular cartilage and 43 genes were differentially expressed between E16 meniscus and cruciate ligaments. Included in our data set were extracellular matrix proteins, transcription factors, and growth factors, including TGF-β modulators (Lox, Dpt) and IGF-1 pathway members (Igf-1, Igfbp2, Igfbp3, Igfbp5). Ingenuity Pathway Analysis revealed that IGF-1 signaling was enriched in the meniscus compared to the other joint structures, while qPCR showed that Igf-1, Igfbp2, and Igfbp3 expression declined with age. We also found that several meniscus-enriched genes were expressed either in the inner or outer meniscus, establishing that regionalization of the meniscus occurs early in development.

Anterior tibial plateau fracture: An often missed injury

BACKGROUND

In most classifications of tibial plateau fractures, including one used most widely-Schatzker classification, fractures are described as a combination of medial and lateral condyle, primarily in the sagittal plane. Coronal component of these fractures, affecting the posterior tibial condyle is now well recognized. What is not described is anterior coronal component of the fracture, what we are calling "anterior tibial condyle fracture". These fractures are often missed on routine antero-posterior and lateral knee X-rays due to an overlap between the fracture and the normal bone.

MATERIALS AND METHODS

Eight cases of anterior tibial condyle fractures with posterior subluxation of the tibia, six of which were missed by the initial surgeon and two referred to us early, are described. Two of the six late cases and both the early ones were operated. Reconstruction of the anterior condyle and posterior cruciate ligament reconstruction was done. Primary outcome measures such as union of the fracture, residual flexion deformity, range of motion and stability were studied at the end of 6 months.

RESULTS

All operated fractures united. There was no posterior sag in any. In those presenting late and were operated, the flexion deformity got corrected in all (average from 15° to 0°) and mean flexion achieved was 100° (range: 80-120°). In those presenting early and were operated, there was no flexion deformity at 6 months and a mean flexion achieved was 115° (range: 100-130°). None of the operated patients had instability.

CONCLUSION

This article attempts to highlight that this injury is often missed. They should be suspected, diagnosed early and treated by reconstruction of anterior condyle, posterior cruciate ligament reconstruction.

Ganglion cysts of the cruciate ligaments: a series of 31 cases and review of the literature

BACKGROUND

A case series for ganglion cyst of the cruciate ligament with MRI findings, clinical presentation, and management options along with review of literature is presented.

METHODS

Of 8663 consecutive patients referred for knee MR imaging, 31 were diagnosed with ganglion cysts of the cruciate ligaments, including 21 men and 10 women of ages 12 to 73 years (mean: 37). A review of charts revealed that knee pain was the chief complaint in all cases. Arthroscopic debridement of ganglion cyst was performed in 11 patients.

RESULTS

MRI proved to be a valuable tool in diagnosing and deciding management of these cases. All 11 patients who underwent arthroscopic treatment were symptom-free on a minimum follow-of one year.

CONCLUSION

Cyst formation associated with cruciate ligament of the knee is an infrequent cause of knee pain. MR imaging was important in confirming the cyst lesions and provided useful information prior to arthroscopy. Arthroscopic debridement of ganglion cyst produced excellent outcome without recurrence. This study describes the pertinent MRI and intraoperative findings of ganglion cyst.

Effect of axial tibial torque direction on ACL relative strain and strain rate in an in vitro simulated pivot landing

Anterior cruciate ligament (ACL) injuries most frequently occur under the large loads associated with a unipedal jump landing involving a cutting or pivoting maneuver. We tested the hypotheses that internal tibial torque would increase the anteromedial (AM) bundle ACL relative strain and strain rate more than would the corresponding external tibial torque under the large impulsive loads associated with such landing maneuvers. Twelve cadaveric female knees [mean (SD) age: 65.0 (10.5) years] were tested. Pretensioned quadriceps, hamstring, and gastrocnemius muscle-tendon unit forces maintained an initial knee flexion angle of 15°. A compound impulsive test load (compression, flexion moment, and internal or external tibial torque) was applied to the distal tibia while recording the 3D knee loads and tibofemoral kinematics. AM-ACL relative strain was measured using a 3 mm DVRT. In this repeated measures experiment, the Wilcoxon signed-rank test was used to test the null hypotheses with p < 0.05 considered significant. The mean (±SD) peak AM-ACL relative strains were 5.4 ± 3.7% and 3.1 ± 2.8% under internal and external tibial torque, respectively. The corresponding mean (± SD) peak AM-ACL strain rates reached 254.4 ± 160.1%/s and 179.4 ± 109.9%/s, respectively. The hypotheses were supported in that the normalized mean peak AM-ACL relative strain and strain rate were 70 and 42% greater under internal than under external tibial torque, respectively (p = 0.023, p = 0.041). We conclude that internal tibial torque is a potent stressor of the ACL because it induces a considerably (70%) larger peak strain in the AM-ACL than does a corresponding external tibial torque.

The contralateral knee joint in cruciate ligament deficiency

BACKGROUND

Patients with unilateral ligament deficiency are believed to have altered kinematics of the contralateral knee, increasing the risk of contralateral joint injury. Therefore, the contralateral knees might not be a reliable normal kinematic control.

PURPOSE

To compare the in vivo kinematics of the uninjured contralateral knees of patients with anterior or posterior cruciate ligament deficiency with knee kinematics of age-matched patients without joint injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten subjects with bilateral healthy knees, 10 patients with acute unilateral anterior cruciate ligament injury, and 10 with acute unilateral posterior cruciate ligament injury participated in this study. Kinematics were measured from 0 degrees to 90 degrees of flexion using imaging and 3-dimensional modeling.

RESULTS

No significant differences were found across the groups in all rotations and translations during weightbearing flexion (P > .9).

CONCLUSION

Patients with unilateral cruciate ligament deficiency did not alter kinematics of the contralateral uninjured knee during weightbearing flexion. In addition, these findings suggest that the included patients with anterior cruciate ligament or posterior cruciate ligament deficiency did not have preexisting abnormal kinematics of the knee.

CLINICAL RELEVANCE

As the contralateral joint kinematics of the injured patients were not affected by the ipsilateral ligament injury in the short term, physicians and researchers might use the contralateral knee as a reliable normal kinematic control.

Unstable stifles without clinical or radiographic osteoarthritis in young goats: an experimental study

Thirteen young, castrated male goats had instability of one stifle (knee joint) created by surgical transection of the cranial cruciate ligament, but did not develop any signs of osteoarthritis (OA) in treated joints when confined in limited space for 8 months. At the end of the experiment, the instability in the stifles had not improved, the joints were normal at radiographic examination, there were no signs of inflammation in the synovial membrane or joint capsule, and fibrosis in these tissues was not evident. The articular cartilage was normal both visually and histologically. This may indicate that the young age of the goats and the restricted physical activity on soft floor had prevented the expected development of OA in the experimentally operated joints. Synovial fluid volumes and proteoglycan concentration were measured in the treated and control joints in 6 of the goats. There seemed to be increased quantity of the proteoglycan aggrecan in the synovial fluid from the treated joints compared to the contralateral joints throughout the course of this study. It was concluded that the turnover of aggrecan in the articular cartilage of the treated joints may have been increased.