Age and Sex-Specific Joint Biomechanics in Response to Partial and Complete ACL Injury in the Porcine Model

Context: Pediatric anterior cruciate ligament (ACL) injury rates are increasing and are highest in adolescent females. Complete ACL tears are typically surgically reconstructed, but there are few guidelines and very limited data regarding the need for surgical reconstruction or rehabilitation for partial ACL tears in skeletally immature patients. Objective: To evaluate the impact of partial (anteromedial bundle) and complete ACL transection on joint laxity and tissue forces under anterior and rotational loads in male and female stifle joints throughout skeletal growth in the porcine model. Design: Descriptive Laboratory Study. Setting: Laboratory. Patients or Other Participants: Sixty male and female Yorkshire cross-breed pigs aged 1.5, 3, 4.5, 6, and 18 months (n=6/age/sex). Main Outcome Measure(s): Joint laxity was measured in intact, anteromedial bundle-transected, and ACL-transected joints under applied anterior-posterior drawer and varus-valgus torque using a robotic testing system. The loading of the soft tissues in the stifle joint was measured under each condition. Results: Anterior-posterior joint laxity increased by 13–50% (p<0.05) after anteromedial bundle transection and 75–178% (p<0.05) after ACL transection. Destabilizations after anteromedial bundle transection increased with age (p<0.05) and were greater in late adolescent females than late adolescent males (p<0.05). In anteromedial bundle-transected joints, the posterolateral bundle resisted the anterior load. In ACL-transected joints, the medial collateral ligament (MCL) contribution was largest, followed by the medial meniscus. MCL contribution was larger while medial meniscus contribution was smaller in males versus females. Conclusions: Partial ACL transection resulted in moderate increases in joint laxity, while the remaining bundle performed the primary ACL function. Destabilizations due to partial ACL transection were largest in late adolescent joints, indicating that operative treatment should be considered in active, late adolescent patients. Increased forces in the MCL and medial meniscus after ACL transection suggest that rehabilitation protocols may need to focus on protecting these tissues.

Assessment of systemic joint laxity in the clinical context: Relevance and replicability of the Beighton score in chronic fatigue

BACKGROUND: Persistent symptoms in patients with systemic joint laxity (SJL) are often equivalent with complications. Screening for SJL is an important part of the assessment of musculoskeletal phenotype. The common measuring tool, the Beighton score (BS), still has unclear evidence. OBJECTIVE: To assess the Beighton score in a clinical context for (1) ability to classify SJL as absent or present (criterion validity), and (2) interrater reliability (physician-physiotherapist), for a dichotomous cut-off (yes/no), as well as for interpretation in categories (no, some, clear SJL). METHODS: This real-world observational study included 149 consecutive patients seeking secondary care for investigation of possible myalgic encephalomyelitis/chronic fatigue syndrome. Assessment was done during a routine examination. Data were evaluated with Cohen’s kappa and Spearman’s rho. RESULTS: BS criterion validity showed poor agreement with the assessment of SJL: percentage agreement was 74 % and kappa 0.39 (3-cut level), 73 % and kappa 0.39/0.45 (4-/5-cut level). The best interrater reliability was moderate (rho 0.66) for interpretation in categories. CONCLUSIONS: The BS alone was not a reliable proxy for SJL and should be supplemented with a targeted history. Nevertheless, its interrater reliability was acceptable, and the categorised score appears to have greater clinical relevance than the dichotomous score.

A Comprehensive Framework to Evaluate the Effects of Anterior Cruciate Ligament Injury and Reconstruction on Graft and Cartilage Status through the Analysis of MRI T2 Relaxation Time and Knee Laxity: A Pilot Study

Background. Anterior cruciate ligament (ACL) tear represents a common orthopedic traumatic issue that often leads to an early development of osteoarthritis. To improve the diagnostic and prognostic techniques involved in the assessment of the joint after the trauma and during the healing process, the present work proposes a multi-parametric approach that aims to investigate the relationship between joint function and soft tissue status before and after ACL reconstruction. Methods. Thirteen consecutive patients who underwent ACL reconstruction were preliminarily enrolled in this study. Joint laxity assessment as well as magnetic resonance imaging with T2 mapping were performed in the pre-operative stage, at four and 18 months after surgery to acquire objective information to correlate knee function and soft tissue condition. Results. Correlations were found between graft and cartilage T2 signal, suggesting an interplay between these tissues within the knee joint. Moreover, graft maturation resulted in being connected to joint laxity, as underlined by the correlation between the graft T2 signal and the temporal evolution of knee function. Conclusions. This preliminary study represents a step forward in assessing the effects of ACL graft maturation on knee biomechanics, and vice versa. The presented integrated framework underlines the possibility to quantitatively assess the impact of ACL reconstruction on trauma recovery and cartilage homeostasis. Moreover, the reported findings—despite the preliminary nature of the clinical impacts—evidence the possibility of monitoring the surgery outcomes using a multi-parametric prognostic investigation tool.

Osteogenesis Imperfecta and Split Foot Malformation due to 7q21.2q21.3 Deletion Including COL1A2, DLX5/6 Genes: Review of the Literature

Copy number variation in loss of 7q21 is a genetic disorder characterized by split hand/foot malformation, hearing loss, developmental delay, myoclonus, dystonia, joint laxity, and psychiatric disorders. Osteogenesis imperfecta caused by whole gene deletions of COL1A2 is a very rare condition. We report a Turkish girl with ectrodactyly, joint laxity, multiple bone fractures, blue sclera, early teeth decay, mild learning disability, and depression. A copy number variant in loss of 4.8 Mb at chromosome 7 (q21.2q21.3) included the 58 genes including DLX5, DLX6, DYNC1I1, SLC25A13, SGCE, and COL1A2. They were identified by chromosomal microarray analysis. We compared the findings in our patients with those previously reported. This case report highlights the importance of using microarray to identify the genetic etiology in patients with ectrodactyly and osteogenesis imperfecta.

Comparison of anterior knee laxity, stiffness, genu recurvatum, and general joint laxity in the late follicular phase and the ovulatory phase of the menstrual cycle

Background One risk factor for anterior cruciate ligament (ACL) injury may be fluctuations in female hormones. This study examined variability in joint laxity, as a risk factor for ACL injury, during the menstrual cycle. Methods Subjects were 15 female university students with regular menstrual cycles. We measured estradiol (E2) concentration, anterior knee laxity (AKL), stiffness, genu recurvatum (GR), and general joint laxity (GJL) during the late follicular and ovulatory phases. AKL was measured as anterior tibial displacement of the femur after application of 44-, 89-, and 133-N loads on the tibia. Stiffness was calculated as Δforce/Δdisplacement at loads of 44–89 N and between 89 and 133 N. GR was measured prone, with the base of the patella distal to the edge of the bed. The University of Tokyo joint laxity test was used to evaluate GJL. Results E2 concentration was significantly higher in the ovulatory phase than in the late follicular phase (p = 0.018), AKL and stiffness did not differ significantly between phases, and GR and GJL were significantly higher in the ovulatory phase than in the late follicular phase (p = 0.011, 0.031). Conclusion These findings suggest that E2 concentrations may affect GR and GJL during the menstrual cycle.

The MRI posterior drawer test to assess posterior cruciate ligament functionality and knee joint laxity

Clinical Magnetic Resonance Imaging (MRI) of joints is limited to mere morphologic evaluation and fails to directly visualize joint or ligament function. In this controlled laboratory study, we show that knee joint functionality may be quantified in situ and as a function of graded posterior cruciate ligament (PCL)-deficiency by combining MRI and standardized loading. 11 human knee joints underwent MRI under standardized posterior loading in the unloaded and loaded (147 N) configurations and in the intact, partially, and completely PCL-injured conditions. For each specimen, configuration, and condition, 3D joint models were implemented to analyse joint kinematics based on 3D Euclidean vectors and their projections on the Cartesian planes. Manual 2D measurements served as reference. With increasing PCL deficiency, vector projections increased significantly in the anteroposterior dimension under loading and manual measurements demonstrated similar patterns of change. Consequently, if combined with advanced image post-processing, stress MRI is a powerful diagnostic adjunct to evaluate ligament functionality and joint laxity in multiple dimensions and may have a role in differentiating PCL injury patterns, therapeutic decision-making, and treatment monitoring.