Three-Dimensional Kinetic and Kinematic Analysis of Gait Symmetry in a Patient with Chronic Low Back Pain Following PRP Injection and One Year After Discectomy: A Case Study

Platelet-rich plasma (PRP) injection has emerged as a novel intervention in the management of chronic low back pain (CLBP), yet evidence regarding its biomechanical impact on gait symmetry remains limited. This study aimed to assess three-dimensional gait mechanics and symmetry following PRP injection and one-year post-discectomy in a male patient with CLBP.

Methods:

A single-subject case study was conducted on a 38-year-old male (height: 182 cm, weight: 99 kg, BMI: 29.9) with a history of L5–S1 discectomy. Three-dimensional motion analysis (Motion Analysis Kestrel, Cortex software v8.0) and force plates (Kistler 9286 BA) were used to evaluate the lower limb kinematics and ground reaction forces during gait, 7 days after PRP injection. Spatiotemporal variables, joint range of motion (ROM) in all planes, and symmetry indices were examined.

Results:

The greatest asymmetry was observed in the knee joint ROM in the frontal plane (swing: 69.78%, stance: 66.77%) and in the transverse plane of the knee (swing: 40.89%) and ankle (stance: 40.25%). Maximal symmetry was noted in the hip (transverse plane, swing: 4.31%). The ground reaction force (GRF) symmetry index indicated pronounced asymmetry in the mediolateral direction (SI: 112.09%), while vertical and anterior-posterior forces demonstrated acceptable symmetry.

Conclusion:

Although PRP injection resulted in partial restoration of biomechanical symmetry in some lower limb variables, significant asymmetry persisted in the frontal and transverse planes, especially in the knee joint and mediolateral GRF direction. These findings highlight the complexity of functional recovery post-intervention and suggest the need for multimodal rehabilitation.