Surgical Correction of Juvenile Bunion



Surgical Correction of Juvenile Bunion


B. David Horn





ANATOMY



  • Metatarsus primus varus resulting in increased intermetatarsal (IM) angle2, 3


  • Obliquity of the medial cuneiform-first metatarsal joint2, 3


  • Medial prominence of the first metatarsal head


  • Valgus angulation through the first metatarsophalangeal joint2, 3


  • Minimal or no deformity through the first interphalangeal joint


  • Lateral translation of sesamoids


  • Plantar-lateral positioning of the abductor hallucis with unopposed pull of the adductor hallucis muscle


  • Lateral subluxation of the extensor hallucis longus and flexor hallucis longus tendons


  • Pronation (internal rotation) of the first toe


  • Differs from an adult bunion



    • Physis of the first metatarsal and proximal phalanx are located proximally (this limits ability to perform proximal osteotomies in skeletally immature patients).


    • The first metatarsophalangeal joint does not have osteoarthrosis.


    • The medial eminence is less prominent in adolescent bunions than in adult bunions.


PATHOGENESIS



  • Multiple theories exist; it is difficult to differentiate primary findings from secondary ones.2, 3, 6


  • Extrinsic and intrinsic factors contribute to formation of adolescent bunions.


  • Intrinsic



    • Metatarsus primus varus


    • Obliquity of the medial cuneiform-first metatarsal joint


    • Long first metatarsal


    • Ligamentous laxity


    • Heel cord contracture causes foot pronation, which in turn places a valgus force on the hallux while walking


  • Extrinsic



    • Shoe wear, particularly those with a narrow toe and elevated heel


NATURAL HISTORY



  • Natural history is believed to be favorable. Most patients with adolescent bunions can be treated nonoperatively.2, 5


PATIENT HISTORY AND PHYSICAL FINDINGS



  • Patients typically present in late childhood or adolescence.2, 3


  • Complaints about appearance of foot


  • Complaints of pain over the medial exostosis or about the first metatarsophalangeal joint


  • Pain is exacerbated by shoe wear.


  • Complaints about finding shoes that are comfortable


  • Physical examination2, 3



    • Areas of tenderness: first metatarsophalangeal joint, medial prominence


    • Alignment when standing and walking


    • Mobility of first metatarsophalangeal joint


    • Skin condition: the clinician should search for calluses, areas of irritation


    • Foot and ankle range of motion


  • Careful neurologic examination

Jul 22, 2016 | Posted by in ORTHOPEDIC | Comments Off on Surgical Correction of Juvenile Bunion
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