PhD Thesis Defense: Ryan Chapman

Wednesday, July 18, 2018, 4:30–6:30pm

Rm. 232 Cummings Hall (Jackson Conference Room)

“From Inertial Measurement Units to Physical Therapy (PT): The Use of Patient Biomechanics to Inform PT Prescription”


Over one million total joint arthroplasty (TJA) procedures occur in the United States (US) annually. Specifically, there are nearly 700,000 total knee arthroplasty (TKA) and 70,000 shoulder arthroplasty (SA) procedures each year. After surgical intervention, patients within respective TJA cohorts receive standardized physical therapy (PT) to recover range of motion (ROM). Currently however, post-TJA PT is not individualized despite the likely existence of patients who need increased or decreased PT to recover adequate ROM post-TJA. In order to facilitate development of individualized rehabilitation plans, measuring ROM throughout the rehabilitation process is necessary. Unfortunately, current ROM monitoring methods are costly (e.g. fluoroscopy), idealized (e.g. goniometry), and may not realistically represent function during activities of daily living (ADL).

One method for capturing ROM that is lower-cost and capable of deployment outside of well-controlled laboratory/clinic environments is inertial measurement units (IMUs). Thus, a novel IMU-based method for monitoring continuous ROM was developed, validated, and implemented. The proposed IMU-based system was validated via optical motion capture with error less than 1.1° and 1.4° in laboratory experiments on the knee and shoulder joints, respectively. The system was deployed pre- and post-total knee arthroplasty (TKA) and shoulder arthroplasty (SA), respectively. For TKA, gait knee flexion improved steadily post-TKA. Patients undergoing total SA (TSA) showed increased time above 90° elevation whereas no metric was significantly related with post-reverse SA (RSA) recovery. Additionally, patient PT sorting methods utilizing statistical thresholds and process controls were developed using gait knee flexion for post-TKA PT sorting and time above 90° for post-TSA PT sorting. Finally, a transverse plane metric was assessed for evaluating post-RSA function. The proposed method is a shift toward telemedicine that allows continuous monitoring of patients pre- and post-TJA. The proposed PT sorting algorithms will facilitate customization of post-TJA rehabilitation.

Thesis Committee

For more information, contact Daryl Laware at