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The coupled effects of crouch gait and patella alta on tibiofemoral and patellofemoral cartilage loading in children.

ABSTRACT: BACKGROUND:Elevated tibiofemoral and patellofemoral loading in children who exhibit crouch gait may contribute to skeletal deformities, pain, and cessation of walking ability. Surgical procedures used to treat crouch frequently correct knee extensor insufficiency by advancing the patella. However, there is little quantitative understanding of how the magnitudes of crouch and patellofemoral correction affect cartilage loading in gait. METHODS:We used a computational musculoskeletal model to simulate the gait of twenty typically developing children and fifteen cerebral palsy patients who exhibited mild, moderate, and severe crouch. For each walking posture, we assessed the influence of patella alta and baja on tibiofemoral and patellofemoral cartilage contact. RESULTS:Tibiofemoral and patellofemoral contact pressures during the stance phase of normal gait averaged 2.2 and 1.0?MPa. Crouch gait increased pressure in both the tibofemoral (2.6-4.3?MPa) and patellofemoral (1.8-3.3?MPa) joints, while also shifting tibiofemoral contact to the posterior tibial plateau. For extended-knee postures, normal patellar positions (Insall-Salvatti ratio 0.8-1.2) concentrated contact on the middle third of the patellar cartilage. However, in flexed knee postures, both normal and baja patellar positions shifted pressure toward the superior edge of the patella. Moving the patella into alta restored pressure to the middle region of the patellar cartilage as crouch increased. CONCLUSIONS:This work illustrates the potential to dramatically reduce tibiofemoral and patellofemoral cartilage loading by surgically correcting crouch gait, and highlights the interaction between patella position and knee posture in modulating the location of patellar contact during functional activities.

SUBMITTER: Brandon SCE

PROVIDER: S-EPMC5809194 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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The coupled effects of crouch gait and patella alta on tibiofemoral and patellofemoral cartilage loading in children.

Brandon Scott C E SCE Thelen Darryl G DG Smith Colin R CR Novacheck Tom F TF Schwartz Michael H MH Lenhart Rachel L RL

Gait & posture 20171205

<h4>Background</h4>Elevated tibiofemoral and patellofemoral loading in children who exhibit crouch gait may contribute to skeletal deformities, pain, and cessation of walking ability. Surgical procedures used to treat crouch frequently correct knee extensor insufficiency by advancing the patella. However, there is little quantitative understanding of how the magnitudes of crouch and patellofemoral correction affect cartilage loading in gait.<h4>Methods</h4>We used a computational musculoskeletal ...[more]

PMID: 29248848

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Project description:ObjectivesThe current study quantified the influence of cartilage defect location on the tibiofemoral load distribution during gait. Furthermore, changes in local mechanical stiffness representative for matrix damage or bone ingrowth were investigated. This may provide insights in the mechanical factors contributing to cartilage degeneration in the presence of an articular cartilage defect.MethodsThe load distribution following cartilage defects was calculated using a musculoskeletal model that included tibiofemoral and patellofemoral joints with 6 degrees-of-freedom. Circular cartilage defects of 100 mm2 were created at different locations in the tibiofemoral contact geometry. By assigning different mechanical properties to these defect locations, softening and hardening of the tissue were evaluated.ResultsResults indicate that cartilage defects located at the load-bearing area only affect the load distribution of the involved compartment. Cartilage defects in the central part of the tibia plateau and anterior-central part of the medial femoral condyle present the largest influence on load distribution. Softening at the defect location results in overloading, i.e., increased contact pressure and compressive strains, of the surrounding tissue. In contrast, inside the defect, the contact pressure decreases and the compressive strain increases. Hardening at the defect location presents the opposite results in load distribution compared to softening. Sensitivity analysis reveals that the surrounding contact pressure, contact force and compressive strain alter significantly when the elastic modulus is below 7 MPa or above 18 MPa.ConclusionAlterations in local mechanical behavior within the high load bearing area resulted in aberrant loading conditions, thereby potentially affecting the homeostatic balance not only at the defect but also at the tissue surrounding and opposing the defect. Especially, cartilage softening predisposes the tissue to loads that may contribute to accelerated risk of cartilage degeneration and the initiation or progression towards osteoarthritis of the whole compartment.

Project description:BackgroundQuantification of dynamic biomechanical strain in articular cartilage in vivo; in situ using noninvasive MRI techniques is desirable and may potentially be used to assess joint pathology.PurposeTo demonstrate the use of static mechanical loading and continuous 3D-MRI acquisition of the human knee joint in vivo to measure the strain in the tibiofemoral articular cartilage.Study typeProspective.SubjectsFive healthy human volunteers (four women, one man; age 25.6?±?1.7) underwent MRI at rest, under static mechanical loading condition, and during recovery.Field strength/sequenceA field strength of 3T was used. The sequence used was 3D-continuous golden angle radial sparse parallel (GRASP) MRI and compressed sensing (CS) reconstruction.AssessmentTibiofemoral cartilage deformation maps under loading and during recovery were calculated using an optical flow algorithm. The corresponding Lagrangian strain was calculated in the articular cartilage.Statistical testsRange of displacement and strain in each subject, and the resulting mean and standard deviation, were calculated.ResultsDuring the loading condition, the cartilage displacement in the direction of loading ranged from a minimum of -673.6?±?121.9 ?m to a maximum of 726.5?±?169.5 ?m. Corresponding strain ranged from a minimum of -7.0?±?4.2% to a maximum of 5.4?±?1.6%. During the recovery condition, the cartilage displacement in the same direction reduced to a minimum of -613.0?±?129.5 ?m and a maximum of 555.7?±?311.4 ?m. The corresponding strain range reduced to a minimum of -1.6?±?7.5% to a maximum of 4.2?±?2.6%.Data conclusionThis study shows the feasibility of using static mechanical loading with continuous GRASP-MRI acquisition to measure the strain in the articular cartilage. By measuring strain during the loading and recovery phases, dynamic strain information in the articular cartilage might be able to be investigated.Level of evidence2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:426-434.

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The coupled effects of crouch gait and patella alta on tibiofemoral and patellofemoral cartilage loading in children.

Publications

The coupled effects of crouch gait and patella alta on tibiofemoral and patellofemoral cartilage loading in children.

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