R43AR080486

Osteoarthritis (OA) research, a primary component of the NIAMS mission, has focused on the hip, knee, and hand, with sparse attention to the foot. First metatarsophalangeal (MTP) joint OA (Hallux Rigidus), a source of substantial pain and limited mobility, is the most common degenerative disease in the foot. Excessive or insufficient 1st ray mobility (FRM) has been associated with numerous painful, disabling, and limb threatening pathologies including: tarsometatarsal OA, Hallux Valgus (HV), Hallux Rigidus (HR), metatarsalgia, diabetic foot ulceration, pes cavus, and pes planus. First ray (medial cuneiform, 1st metatarsal, proximal phalanx, and hallux) mobility is the superior or inferior displacement of these bony structures in response to a vertically applied load. While a couple of laboratory devices exist to test 1st ray hypermobility (FRM ≥8mm), there are no commercially available, reliable, user friendly, FRM devices for the clinic. The study goal is to redesign and improve the 1st Ray Mobility and Position (MAP1st) version 1 (V1) prototype (PCT/US21/22791) to provide a clinically viable instrument to measure 1st ray mobility and position. MAP1st V1 has several limitations, including i) weight, ii) ungrounded hindfoot, iii) visual measurement, iv) tethered laptop, and v) manual data entry. The Specific Aim is to develop MAP1st version 2 (V2) to increase the reliability, utility, efficiency, and ease of use for measuring FRM, position, and stiffness. In MAP1st V2, a transducer will measure mobility and position while a smartphone-based App will replace the laptop and compute stiffness. Outcomes will be stored in an encrypted file and transferred to electronic medical records. Using this device, and guided by power analysis, a data set (n=80 feet) will be acquired from 20 healthy individuals with asymptomatic rectus (nrf = 20) and planus (npf = 20) feet, 10 patients with hallux valgus feet (nhvf = 20) and 10 patients with hallux rigidus feet (nhrf = 20). Intra-rater and inter-rater reliability will be assessed from replicated measures, while subgroup differences will also be examined. Device utility will be assessed by distinguishing FRM between the healthy and pathologic groups using Generalized Estimation Equations (GEE). A usability questionnaire will assess clinician (MD, DPM, DPT, technician) ease of use for V1 versus V2. Three hypotheses will be tested: (1) Intra- rater and inter-rater reliability will exhibit an ICC (2,1)rt0.75 for use of MAP1st V2; (2) First ray mobility, position, and stiffness will be different across individuals with asymptomatic rectus, asymptomatic planus, hallux valgus, and hallux rigidus feet demonstrating device utility; (3) Usability and efficiency will be improved between MAP1st V1 and V2. This investigational team has collaborated on 10+ projects and co-published 50+ publications on foot biomechanics. Further, pilot data supports MAP1st ability to detect hypermobility in planus vs. rectus feet. Hence, a smooth, successful completion of this project is anticipated. MAP1st V2 will address an unmet clinical need by providing reliable first ray mobility and position measurements for clinical assessment which could be used to formulate treatment algorithms that will ultimately benefit the patient.