Kinematic, kinetic, and musculoskeletal modeling analysis of gait in patients with cervical myelopathy using a severity classification

Abstract

BACKGROUND CONTEXTAlthough a few reports have shown a change in gait motion in cervical myelopathy (CM) patients using a three-dimensional (3D) gait analysis system, there has been no detailed quantitative investigation of their gait including musculoskeletal modeling parameters. Also, 3D gait analysis using a classification of severity has not been substantiated. PURPOSEThis study aimed to investigate kinematic, kinetic, and musculoskeletal modeling parameters of gait motion in CM patients using a severity classification. STUDY DESIGNProspective cohort and cross-sectional study. PATIENT SAMPLEForty-two patients with CM and 40 healthy, age-matched volunteers. OUTCOME MEASURESLower extremity spatiotemporal, kinematic, kinetic, and musculoskeletal modeling parameters. METHODSSubjects were classified as to its severity using the Japan Orthopaedic Association score excluding the upper extremity items: group 1 (>10 points); group 2 (7–9 points); and group 3 (<6 points). A 3D motion analysis system and musculoskeletal modeling software were used to obtain the spatiotemporal, kinematic (the lower extremity joints angles in the sagittal plane), kinetic (the lower extremity joints moment and power in the sagittal plane), and musculoskeletal modeling parameters (the muscle-tendon length and velocity). RESULTSGenu recurvatum, deteriorated lower-extremity joint motion, and muscle-tendon velocity were observed in severe CM patients (group 3). Muscle-tendon velocities of the long head of the biceps femoris in controls and mild CM patients (groups 1 and 2) showed a bimodal waveform in the negative direction during the initial contact and preswing phases, whereas these characteristics were not present in severe CM patients (group 3). CONCLUSIONSThe strategies of the knee joint moment during gait motion in severe CM patients were different from those of the normal gait pattern. The imbalance between agonist and antagonist muscle tissue during gait could be involved in the occurrence of genu recurvatum. It might be important for CM patients to consider improving the contraction or extension velocity of the biceps femoris muscle during each gait phase from the early stages of symptoms.