Dataset Information

The effective quadriceps and patellar tendon moment arms relative to the tibiofemoral finite helical axis.

ABSTRACT: The moment arm is a crucial parameter for understanding musculoskeletal dynamics as it defines how linear muscle force is transformed into a moment. Yet, for the quadriceps tendon this parameter cannot be directly calculated, as the patella creates a dynamic fulcrum. Thus, the effective quadriceps moment arm (EQma) was developed to define the quadriceps force to tibial moment relationship. In vivo data in regards to the EQma are lacking and the critical question of how patellofemoral kinematics may influence the EQma remains unresolved. Therefore, the purpose of this study was to quantify the in vivo EQma during a knee extension exercise in asymptomatic controls and to correlate the EQma with sagittal plane patellofemoral kinematics. While subjects (30F/10M, 26.5±5.6 years, 167.5±10.2 cm, 62.6±10.7 kg) cyclically flexed-extended their knees within the MR scanner, dynamic cine-phase contrast and cine MR images were acquired. From these data, patellofemoral kinematics, the ratio of the patellar tendon to quadriceps force, the patellar tendon moment arm, and the EQma were quantified. The EQma trended upwards (32.9-45.5 mm (females) and 31.5-47.1 mm (males)) as the knee angle decreased (50-10°). The quadriceps had a mechanical advantage (ratio of patellar to quadriceps tendon forces >1.0) for knee angles ?20°. The EQma did not correlate with sagittal plane patellofemoral kinematics. As this is the first study to characterize the EQma in vivo during dynamic volitional activity, in a large group of asymptomatic controls, it can serve as a foundation for future knee joint models and to explore how pathological conditions affect the EQma.

SUBMITTER: Im HS

PROVIDER: S-EPMC4662057 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The effective quadriceps and patellar tendon moment arms relative to the tibiofemoral finite helical axis.

Im Hyun Soo HS Goltzer Oren O Sheehan Frances T FT

Journal of biomechanics 20150415 14

The moment arm is a crucial parameter for understanding musculoskeletal dynamics as it defines how linear muscle force is transformed into a moment. Yet, for the quadriceps tendon this parameter cannot be directly calculated, as the patella creates a dynamic fulcrum. Thus, the effective quadriceps moment arm (EQma) was developed to define the quadriceps force to tibial moment relationship. In vivo data in regards to the EQma are lacking and the critical question of how patellofemoral kinematics ...[more]

PMID: 26520912

Similar Datasets

Project description:PurposeQuadriceps dysfunction is ubiquitous after anterior cruciate ligament reconstruction, especially when using bone-patellar tendon-bone (BPTB) autografts. The role of patellar tendon hypertrophy after graft harvest on knee extensor strength is unknown. The purpose of this study was to determine the predictive ability of patellar tendon (PT) and quadriceps muscle (Quad) cross-sectional area (CSA) on knee extensor strength 1-2 months after ACLR using BPTB autografts.MethodsThis is a cross-sectional analysis of a cohort 1-2 months after ACLR using BPTB autograft. Peak knee extensor torque, and PT and Quad CSA measured using ultrasound imaging, were collected in 13 males and 14 females. Simple linear regressions compared quadriceps strength index (QI) against limb symmetry index (LSI) in PT and Quad CSA. Multiple linear regressions with sequential model comparisons predicting peak knee extensor torque were performed for each limb. The base model included demographics. Quad CSA was added in the first model, then PT CSA was added in the second model.ResultsBoth PT (p < 0.001, R2 = 0.693) and Quadriceps CSA (p = 0.013, R2 = 0.223) LSI had a positive linear relationship with QI. In the involved limb, addition of PT CSA significantly improved the model (R2 = 0.781, ΔR2 = 0.211, p for ΔR2 < 0.001). In the uninvolved limb, the addition of Quad CSA improved the model, but the addition of PT CSA did not.ConclusionPT LSI was more predictive of QI than Quad CSA LSI. Involved limb PT CSA mattered more in predicting peak knee extensor torque than did Quad CSA, but in the uninvolved limb, Quad CSA was the most important predictor of peak knee extensor torque. Graft site patellar tendon hypertrophy is key for strong quadriceps early after ACLR. Early targeted loading via exercise to promote healing of the graft site patellar tendon may bring patients a step closer to winning their battle against quadriceps dysfunction.Level of evidenceLevel I.

Dataset Information

The effective quadriceps and patellar tendon moment arms relative to the tibiofemoral finite helical axis.

Publications

The effective quadriceps and patellar tendon moment arms relative to the tibiofemoral finite helical axis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets