Isolated Medial Malleolar Fracture

Definition

  • Fracture of the medial distal tibia at the level of the ankle joint.

Aetiology

  • Commonly associated with rotational injuries of the ankle, this can occur either as an inversion or eversion injury.
  • Sports injuries or falls while walking most common cause for ankle fractures.
  • Often associated with increased BMI and smoking.

Epidemiology

  • Ankle fractures occur in roughly 187 people per 100,000.
  • Unimalleolar ankle fractures (lateral and medial) account for 60-70% of all ankle fractures.

Anatomy

  • The medial malleolus is a core component of the talocrural joint, also known as the ankle joint.
  • This joint is comprised of the tibia (providing the plafond and medial and posterior components), the fibula (providing the lateral component) and the talus.
  • The distal tibia and fibula provide a rectangular socket (termed the mortise) that articulate with the talar trochlea.
  • This joint acts as a mortise and tenon joint
  • A membranous ligament spans between the tibia and fibular termed the interosseous membrane. The distal aspect forms the tibiofibular ligament forming a syndesmotic joint.

Pathology

  • Most common fracture pattern

Classification

Hervsovici Classification

Hervscovici Classification
AAvulsion fracture of medial malleolus tip, involves deltoid ligament
BIntermediate fracture
CFracture at the level of the plafond
DPlafond fracture/Pilon Fracture

History

  • Most common symptoms are pain in the ankle particularly along the medial side of the ankle and pain with movement/weight bearing on the affected side.
  • Most commonly occurs after inversion/eversion injury of the ankle
  • Patient may present reporting they assumed it was “just a strain or sprain but pain didn’t improve”

Examination

Inspection

  • Swelling of ankle
  • Rare to have deformity,

Palpation

  • Tenderness along the medial aspect of the ankle

Movement

  • Pain on movement of ankle
  • Inability to properly weight bare

Investigations

XR

  • First line investigation for medial malleolus fractures.
  • Requires AP, Lateral and Mortise views.
  • Ensure ankle is within the joint. Any subluxation or dislocation requires early reduction.
  • Appropriate views to determine potential associated medial malleolus/posterior malleolus.
  • Important to determine not only the presence of a fracture but also review for tibiotalar instability (Syndesmosis instability) as any tibiotalar instability is a strong determinant for operative management.
  • Consider imaging of full tibia and fibula as well for potential fracture proximally (eg Maisonneuve fracture) due to the strong interosseous membrane transmitting force across both bones.

Differential Diagnosis

  • Ligamentous injury
    • Deltoid
  • Bimalleolar fracture
  • Trimalleolar fracture
  • Foot fractures
    • Talus/Calcaneus etc

Treatment

  • One of the most important aspects of any ankle fracture is to determine if the talus is within the mortise. If there is incongruence with the joint then early closed reduction and plaster of the ankle joint is necessary. This not only aids with pain and swelling but also prevents any further damage to the congruent surfaces. This does not need to be definitive management but will provide time to organise appropriate management as required.

Non Operative

  • A

Operative

  • A

Surgical Technique

(To be later linked)

Complications

  • Uncommon in appropriately treated isolated medial malleolar fractures.
  • Increased risk of complications occur with diabetes/smoking, poor compliance with weight bearing restrictions or poor engagement with physiotherapy once movement allowed.
  • Due to compressive natuer of conforming force, inversion

Prognosis

  • Prognosis of this injury is heavily determined by the appropriate diagnosis and treatment
  • Most important aspect for prognosis is by retaining acceptable ankle congruence. Failure to do so can lead to arthritis requiring future treatments including ankle replacement or fusion.

References

Daly PJ, Fitzgerald RH Jr, Melton LJ, Ilstrup DM. Epidemiology of ankle fractures in Rochester, Minnesota. Acta Orthop Scand. 1987 Oct;58(5):539-44. doi: 10.3109/17453678709146395. PMID: 3425285.

Goost H, Wimmer MD, Barg A, Kabir K, Valderrabano V, Burger C. Fractures of the ankle joint: investigation and treatment options. Dtsch Arztebl Int. 2014;111(21):377-388. doi:10.3238/arztebl.2014.0377

Jensen SL, Andresen BK, Mencke S, Nielsen PT. Epidemiology of ankle fractures. A prospective population-based study of 212 cases in Aalborg, Denmark. Acta Orthop Scand. 1998 Feb;69(1):48-50. doi: 10.3109/17453679809002356. PMID: 9524518

Lindsjö U. Operative treatment of ankle fractures. Acta Orthop Scand Suppl. 1981;189:1-131. doi: 10.3109/ort.1981.52.suppl-189.01. PMID: 6787831.

Marsh, JL, Saltzman, CL. Ankle Fractures. In: Rockwood and Green’s Fractures in Adults, Bucholz, RW and Heckman, JD (Eds), Lippincott Williams and Wilkins, Philadelphia 2002. p.2001.

Author Contribution

Dylan Ellis, Orthopaedic Resident, 2021