Review Question - QID 218667

A 52-year-old female presents to your clinic with the chief complaint of right foot pain. She states the pain began insidiously and has worsened over the last 3 months. She feels like she has a rock in her shoe at times and states her pain is improved with well-padded tennis shoes compared to walking barefoot. On exam, the pain is localized to the level of the 2nd metatarsophalangeal (MTP) joint, and no gross deformity is present on inspection. Passive flexion and extension of the 2nd MTP are full, with pain as the toe is hyperextended. There is no palpable click with compression of the forefoot but dorsal subluxation of the 2nd proximal phalanx base is appreciated with modified Lachman testing. A radiograph is seen in Figure A. What is the diagnosis most likely causing her symptoms?