summary Synovitis of 2nd MTP is the most frequent monoarticular synovitis of the MTP joint frequently associated with elongated 2nd metatarsal or a hallux valgus deformity. Diagnosis is made clinically with tenderness plantarly over 2nd MTP plantar plate or over dorsal capsule. MRI can be helpful in cases of unclear diagnosis. Treatment is a trial of conservative management with shoe modifications and NSAIDs. Surgical management is indicated for patients with progressive symptoms who fail nonoperative management. Epidemiology Risk factors elongated second metatarsal relative to the first metatarsal Morton Foot hallux valgus deformity Etiology Pathoanatomy synovitis causes the capsuloligamentous apparatus of the MTP joint to become stretched stretching leads to instability login to view 1 more bullet attenuation of plantar plate extension of MTP joint sagittal plane deformity associated with cross-over toe deformity MTP instability can lead to dorsal dislocation of MTP joint predisposition to hammer toe deformity Anatomy Cadaveric cross section of plantar plate MRI of plantar plate Presentation Symptoms pain warm joint fullness of joint Physical exam pain and tenderness may have pain in second web space tenderness may be worse plantarly over plantar plate or over dorsal capsule caused by inflammation or extrinsic pressure on interdigital nerve pain with range of motion decreased with traction global swelling of MTP motion decreased plantar flexion deformity & motion deformity is often passively correctable in the predislocation stages instability, if present, can be demonstrated with the dorsal drawer test if able to dorsally sublux then attenuation of plantar plate present as deformity progresses second toe may cross over adjacent toe in a varus or valgus deformity login to view 2 more bullets Imaging Radiographs recommended views weight-bearing AP and lateral views of foot findings widening or medial-lateral joint space imbalance of second MTP joint dorsal subluxation of MTP joint login to view 1 more bullet varus or valgus deformity of toe MRI indications if diagnosis unclear quantify the extent of plantar plate or ligamentous disruption Differential Morton's neuroma may mimic Mortons neuroma important to differentiate MTP synovitis from interdigital neuroma because a steroid injection into the interdigital space may weaken the capsuloligamentous structures at MTP joint leading to progressive deformity Treatment Nonoperative activity/shoe wear modifications, NSAIDs, external support of MTP joint indications login to view 1 more bullet technique login to view 3 more bullets Operative synovectomy indications login to view 2 more bullets distal oblique shortening MT osteotomy (Weil procedure) indications login to view 1 more bullet technique login to view 3 more bullets FDL-to-EDL tendon transfer (Girdlestone-Taylor) or MTP capsular release with extensor tendon lengthening indications login to view 2 more bullets Complications Vascular compromise if correcting a chronic dislocation the soft tissue, including vasculature, can contract stretching of the vasculature can compromise flow procedure may need to be reversed to save digit