MRI
MRI demonstrates subchondral insufficiency fracture in the head of the second metatarsal, evidenced by curvilinear hypointensity on the proton density image (image 1), with adjacent reactive marrow edema. The articular surface of the metatarsal head is congruent and the second metatarsophalangeal joint is in anatomic alignment. There is reactive edema in the adjacent soft tissues. No loose bodies are present.
MRI显示第二跖骨头软骨下不全性骨折，表现为质子像上线样低信号（图1）；伴临近反应性骨髓水肿。解剖定位于第2跖趾关节，跖骨头关节面；临近软组织反应性水肿，无游离体存在。
Radiograph:
The patient underwent conservative management of symptoms. Oblique radiograph of the left foot performed two years later demonstrates flattening and mild concavity of the head of the second metatarsal, progressed from the previous MRI. There is a small osseous projection from the medial aspect of the head of the second metatarsal, reflecting sequelae of subchondral collapse, which is characteristic of the diagnosis. No osteochondral loose body is present.
患者采取保守治疗。两年后左足平片示第二跖骨头扁平并轻度凹陷，较之前MR片进展。第2跖骨头内侧缘骨性突起，反应出软骨下塌陷的结果，这是诊断的特征表现。无骨软骨游离体存在。
- Freiberg disease/infraction
- Normal variant, flattened morphology of the head of the metatarsal 正常变异
- Fracture of metatarsal head or neck 跖骨头或颈骨折
- Rheumatoid arthritis 类风湿性关节炎
Freiberg infraction/disease
- Osteochondral fracture versus osteonecrosis of the head of a metatarsal (most frequently the second metatarsal) with progressive subchondral collapse.
- Bilateral disease in approximately 10% of cases.
- Etiology病因学:
- Chronic repetitive trauma is the favored theory. Compression and altered biomechanics from shoes (i.e., heels) have been postulated, given the female predilection.
- Primary avascular necrosis also has been proposed.
骨软骨骨折相对跖骨头缺血性坏死（最常见第2跖骨），进展性软骨下塌陷；
大约10%，双侧发病；
慢性重复性损伤是目前最被支持的理论。
鉴于女性喜爱穿高跟鞋等导致的挤压及生物力学的改变。
原发性跖骨头缺血性坏死也已被提出。
- Early disease
- Cystic changes and flattening of the head of the metatarsal
- Widening of the metatarsophalangeal joint
- Late disease
- Osteochondral fragmentation/defect
- Sclerosis of the head of the metatarsal
- Cortical thickening
- Smillie classification system
- Stage I: Fissure fracture of the ischemic epiphysis
- Stages II to V: Increasing stage with worsening severity of subchondral collapse
- Stage IV: Presence of osteochondral loose body
- Stage V: Osteoarthritic change
早期病变：跖骨头囊变、变扁；跖趾关节间隙增宽；
晚期病变：软骨的破碎/缺损；跖骨头硬化；皮质增厚；
I：缺血骨骺的裂隙骨折；
II-V：不断加重的软骨下塌陷；
IV：骨软游离体的出现；
V：骨性关节炎的改变。
- There is a female gender predilection (3:1 ratio to male patients)
女性好发，3：1
- Peak age is 10 to 18 years (adolescents青少年).
Clinical presentation
- Patients present with pain, edema, and decreased range of motion of the affected metatarsophalangeal joint.（疼痛、肿胀、跖趾关节活动度下降）
- Symptoms are worsened with weight-bearing.（负重时症状加重）
- Radiography:
- Widening of the metatarsophalangeal joint is seen in the early phase of the disease.
- Sclerosis and cystic changes are seen in the head of the metatarsal.
- Radiographs shows progressive flattening and concavity of the articular surface of the head of the metatarsal (central articular surface is typically affected first).
- Loose body can be seen in late disease.
- MRI:
- MRI demonstrates marrow edema (T2-hyperintense, T1 hypointense signal) in the head of the metatarsal.
- Serpentine T2 hypointense in the subarticular/subchondral region.
- Sclerosis in the later phase of the disease will be T2 hypointense.
早期主要见跖趾关节间隙增宽；
跖骨头硬化囊变；
X片显示进展性的跖骨头关节面的变扁凹陷（关节面中央首先受侵）；
晚期可见游离体；
MR表现为跖骨头骨髓水肿（长t1长t2）；
关节面下/软骨下区域的线样迂曲t2低信号；
晚期骨质硬化导致的t2低信号。
- Normal variant, flattened morphology of the head of the metatarsal
- Fracture of metatarsal head or neck
- Rheumatoid arthritis
- Carmont MR, Rees RJ, Blundell CM. Current concepts review: Freiberg\’s disease. Foot Ankle Int. 2009;30(2):167-176.
- Stanley D, Betts RP, Rowley DI, Smith TW. Assessment of etiologic factors in the development of Freiberg\’s disease. J Foot Surg. 1990;29(5):444-447.
- Talusan PG, Diaz-Collado PJ, Reach JS Jr. Freiberg\’s infraction: Diagnosis and treatment. Foot Ankle Spec. 2014;7(1):52-55.