summary Midfoot Arthritis is defined as arthritis of the midfoot which includes the following joints: naviculocuneiform joint, intercuneiform joints, and metatarsal cuneiform joints. Diagnosis is made with plain radiographs of the foot often showing joint space narrowing and dorsal osteophyte formation in the midfoot. Treatment can be nonoperative or operative depending on patient age, patient activity demands, severity of arthritis, and presence of midfoot deformity. Etiology Pathophysiology etiology idiopathic (primary) osteoarthritis is most common form of midfoot arthritis posttraumatic inflammatory pathoanatomy large forces seen by joints that have limited motion soft tissues that support joints see abnormally high forces over time results in midfoot collapse Presentation Symptoms midfoot pain (and in arch) with toe off Physical exam inspection deformity shows longitudinal arch collapse with weight bearing midfoot collapse (look like PTTI) forefoot abduction hindfoot valgus equinuus contracture of achilles tendon halux valgus palpation palpation of arch/midfoot leads to pain Imaging Radiographs lateral loss of co-linearity between talus-1st MT (Meary's line) apex of deformity is at the level of the midfoot may show collapse of longitudinal arch AP arthritic signs in midfoot inflammatory etiology consistent with symmetric degeneration across midfoot abduction of forefoot Differential PTTI post-traumatic Lis-Franc injury Lateral ankle instability Treatment Nonoperative NSAIDS, activity modification, orthotic/bracing indications first line of treatment modalities steroid injections under radiographic guidance can be diagnostic and therapeutic orthotics cushioned heel longtidunal arch supports stiff sole with a rocker bottom Operative midfoot arthrodesis, +/- TAL, +/- hindfoot realignment indications failure of non operative management outcomes midfoot joints are non-essential joints arthrodesis results in close to normal foot function use of autograft associated with decreased nonunion rates Achilles tendon lengthening/hindfoot realignment may need to be done concomitantly Technique Midfoot arthrodesis approach realignment arthrodesis close to full physiologic foot function, especially during push-off, can be established tarsometatarsal joints are 2-3 cm deep and warrant appropriate preparation prior to fusion realignment arthrodesis fusion of the first ray via the first tarso-metatarsal joint fusion of the second/third rays via the naviculocuneiform/intercuneiform joints do not fuse the 4th/5th tarsometatarsal joints the lateral ray mobility facilitates foot accomodation during stance interpositional arthroplasties of the 4th/5th tarsometatarsal joints select cases will maintain length of lateral column can assist with gait accommodation instrumentation may use screws, staples, plates designed for midfoot fusions concomitant procedures Achilles tendon lengthening hindfoot realignment