Disclosures: Steven L. Jow, MD: No financial relationships or conflicts of interest

Background and/or Objectives: Runner’s dystonia (RD) is a task-specific focal dystonia characterized by involuntary muscle activation in the lower limbs and/or trunk, which results in gait abnormalities. Developing a treatment plan for patients with RD requires that, in addition to identifying dystonia that clinicians and researchers also identify musculoskeletal impairments that may contribute to patients’ aberrant gait. Therefore, the aim of this study is to characterize ultrasound and kinematic abnormalities in RD patients with stiff knee (i.e., leg extension) gait patterns.

Design: Case Series

Setting: Research Hospital

Participants: Musculoskeletal knee joint ultrasound and kinematic 3D motion analysis assessments were performed in four RD patients with stiff knee gait patterns.

Interventions: Intervention not applicable.

Main Outcome Measures: For musculoskeletal ultrasound, outcome measures included suprapatellar effusion, Baker’s cyst, cortical irregularity, medial meniscus tear, lateral meniscus tear, and tendinopathy. For gait, kinematic abnormalities at the knee and ankle included restricted or excessive joint range of motion throughout the gait cycle.

Results: The musculoskeletal ultrasound findings were: suprapatellar effusion in the dystonic limb (n=3), Baker’s cyst in dystonic limb (n=1), Baker’s cyst in non-dystonic limb (n=1), cortical irregularity (n=3), medial meniscus tear (n=0), lateral meniscus tear (n=0), and tendinopathy (n=0). Kinematic abnormalities were: knee hyperextension (n=4) and excessive plantarflexion (n=3) in stance phase, limited plantarflexion at toe off (n=3), restricted knee flexion in swing phase (n=3), and plantarflexion-knee extension coupling (n=3).

Conclusions: Patients with RD may develop musculoskeletal abnormalities in their dystonic or non-dystonic limbs including structural abnormalities (e.g., cysts, effusion, tears) and atypical range of motion during gait. These patients with joint and/or gait problems may be referred to either neuro- or sports medicine-focused clinicians. Therefore, all providers need to be aware of the scope of problems observed in patients with RD in order to assess for all possible factors contributing to stiff knee gait patterns.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/ultrasound-knee-joint-abnormalities-in-patients-with-a-stiff-knee-gait-pattern-associated-with-runners-dystonia-a-case-series/