Repair of Lateral Meniscus Posterior Horn Detachment Lesions A Biomechanical Evaluation
ABSTRACT BACKGROUND:Posterior horn detachment (PHD) lesions of the lateral meniscus are commonly associated with acute anterior cruciate ligament (ACL) tears. Multiple surgeons have advocated for repair of this lesion at the time of ACL reconstruction. However, the biomechanical consequences of this lesion and its subsequent repair have not been evaluated. HYPOTHESIS:The PHD lesion of the lateral meniscus will lead to increased tibiofemoral contact pressures, and repair of this lesion to bone via a tibial tunnel can restore normal contact pressures during simulated gait. STUDY DESIGN:Controlled laboratory study. METHODS:Lateral compartment contact pressures were measured via a sensor on the tibial plateau in 8 cadaver knees with the knee intact, after sectioning the posterior horn of the lateral meniscus to simulate PHD, and after repairing the injury. The repair was performed using an ACL tunnel guide to drill a tunnel from the anteromedial tibia to the posterior horn attachment site. Dynamic pressure data were continuously collected using a conductive ink pressure sensing system while each knee was moved through a physiological gait flexion cycle. RESULTS:Posterior horn detachment caused a significant increase in tibiofemoral peak contact pressure from 2.8 MPa to 4.2 MPa (P = .03). After repair of the lesion to bone was performed through a transtibial tunnel, the peak contact pressure was 2.9 MPa. Posterior horn detachment also significantly decreased the maximum contact area over which tibiofemoral pressure is distributed from 451 mm(2) in the intact state to 304 mm(2) in the detached state. Repair of the PHD lesion increased the maximum contact area to 386 mm(2), however, this area was also significantly less than in the intact state (P = .05). CONCLUSION:Posterior horn detachment of the lateral meniscus causes increased peak tibiofemoral contact pressure. The peak pressure can be reduced to a normal level with repair of the lesion to bone via a transtibial tunnel. CLINICAL RELEVANCE:Posterior horn detachment of the lateral meniscus is a lesion often associated with an acute ACL tear. Debate exists concerning the importance of repairing PHD lesions at the time of ACL reconstruction. The data provided in this study may influence surgeons' management of the lesion.
- SourceAvailable from: Lennart Jans
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- "In practice, the attachment is more anterior than one might expect, and if no low-signal structure can be seen directly attaching to bone, a tear is likely present (Fig. 8). A meniscal detachment in this location is important to detect because it renders the entire lateral meniscus unstable and substantially increases tibial loading, which could predispose to early osteoarthritis . "
ABSTRACT: ObjectiveMagnetic resonance imaging (MRI) findings in anterior cruciate ligament (ACL) injury are well known, but most published reviews show obvious examples of associated injuries and give little focus to paediatric patients. Here, we demonstrate the spectrum of MRI appearances at common sites of associated injury in adolescents with ACL tears, emphasising age-specific issues.MethodsPictorial review using images from children with surgically confirmed ACL tears after athletic injury.ResultsACL injury usually occurs with axial rotation in the valgus near full extension. The MRI findings can be obvious and important to management (ACL rupture), subtle but clinically important (lateral meniscus posterior attachment avulsion), obvious and unimportant to management (femoral condyle impaction injury), or subtle and possibly important (medial meniscocapsular junction tear). Paediatric-specific issues of note include tibial spine avulsion, normal difficulty visualising a thin ACL and posterolateral corner structures, and differentiation between incompletely closed physis and impaction fracture.ConclusionACL tear is only the most obvious sign of a complex injury involving multiple structures. Awareness of the spectrum of secondary findings illustrated here and the features distinguishing them from normal variation can aid in accurate assessment of ACL tears and related injuries, enabling effective treatment planning and assessment of prognosis.Teaching points• The ACL in children normally appears thin or attenuated, while thickening and oedema suggest tear.• Displaced medial meniscal tears are significantly more common later post-injury than immediately.• The meniscofemoral ligaments merge with the posterior lateral meniscus, complicating tear assessment.• Tibial plateau impaction fractures can be difficult to distinguish from a partially closed physis.• Axial MR sequences are more sensitive/specific than coronal for diagnosis of medial collateral ligament (MCL) injury.Insights into Imaging 05/2013; 4(3). DOI:10.1007/s13244-013-0250-z
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- "Tears of the posterior root attachments of both menisci lead to significantly increased load in the respective compartments due to loss of hoop containment.3,34 Significantly increased compartment loads result in early osteoarthritis due to the resultant load transfer on the articular cartilage.16,18 "
ABSTRACT: Context:Magnetic resonance imaging (MRI) affords high-resolution visualization of the soft tissue structures (menisci, ligaments, cartilage, etc) and bone marrow of the knee.Evidence Acquisition:Pertinent clinical and research articles in the orthopaedic and radiology literature over the past 30 years using PubMed.Results:Ligament tears can be accurately assessed with MRI, but distinguishing partial tears from ruptures of the anterior cruciate ligament (ACL) can be challenging. Determining the extent of a partial tear is often extremely difficult to accurately assess. The status of the posterolateral corner structures, menisci, and cartilage can be accurately evaluated, although limitations in the evaluation of certain structures exist. Patellofemoral joint, marrow, tibiofibular joint, and synovial pathology can supplement physical examination findings and provide definitive diagnosis.Conclusions:MRI provides an accurate noninvasive assessment of knee pathology.Sports Health A Multidisciplinary Approach 01/2013; 5(1):78-107. DOI:10.1177/1941738112468416
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ABSTRACT: Age-related declines in source memory have been observed for various stimuli and associated details. These impairments may be related to alterations in brain regions contributing to source memory via material-independent processes and/or regions specialized for processing specific materials. Using event-related functional magnetic resonance imaging, we investigate the effects of aging on source memory and associated neural activity for words and objects. Source accuracy was equally impaired in older adults for both materials. Imaging data revealed both groups recruited similar networks of regions to support source memory accuracy irrespective of material, including parietal and prefrontal cortices (PFC) and the hippocampus. Age-related decreases in material-independent activity linked to postretrieval monitoring were observed in right lateral PFC. Additionally, age-related increases in source accuracy effects were shown in perirhinal cortex, which were positively correlated with performance in older adults, potentially reflecting functional compensation. In addition to group differences in material-independent regions, age-related crossover interactions for material-dependent source memory effects were observed in regions selectively engaged by objects. These results suggest that older adults' source memory impairments reflect alterations in regions making material-independent contributions to source memory retrieval, primarily the lateral PFC, but may be further impacted by changes in regions sensitive to particular materials.Cerebral Cortex 05/2011; 22(1):37-50. DOI:10.1093/cercor/bhr056 · 8.67 Impact Factor