Lateral Malleolus Fracture 824.2

synonyms: lateral malleolus fracture, ankle fracture

Lateral Malleolus Fracture ICD-9

Lateral Malleolus Fracture Etiology / Epidemiology / Natural History

• Unstable fractures treated non-operatively can lead to increased lateral malleolar malunion, delayed rehab,

Lateral Malleolus Fracture Anatomy

• ROM=32 dorsiflexion, 45 plantar flexion.  10 dorsiflexion required for normal gait, 20-30 for athletics. (Lindsjo, CORR 199:68-71, 1985)
• medial ligaments=superficial & deep(strongest) deltoid.  Superficial deltoid is from anterior colliculus of medial malleolus to talus.calcaneous.navicular.  Deep deltoid is from posterior colliculus of tibia to talus
• lateral ligaments=anterior talofibular, calcaneofibular, posterior talofibular
• syndesmosis=anterior inferior tibiofibular(intracapsular), posterior inferior tibiofibular, inferior transverse, interosseus
• ligament.  AITFL runs from Chaputs tubercle on anterolateral tibia to Wagstaffe's tubercle on anterior lateral malleolus.  PITFL runs from posterior malleolus ie Volkmann's tubercle. 
• fibula bears 6-16% of body weight
• superficial peroneal n & sural n lateral
• saphenous nerve and posterior tibial nerve medially.  Saphenous nerve runs with long saphenous vein in front of medial malleolus usually dividing into two branches running on either side of the vein.  Saphenous nerve supplies medial NWB side of middle and hind foot.
• planter flexion causes IR of talus. Dorsiflexion causes ER of talus and posterlateral translation and ER of fibula.
• fusion=neutral dorsiflexion, 5-10°valgus, 5-10 external rotation, neutral mediolateral displacement, posterior translation of the talus with respect to the tibia of 1cm.
• lateral displacement of the talus by 1mm reduces the weight bearing area by 42%. (Ramsey, JBJS 58A:356-357, 1976)
• sural nerve supplies lateral heel and lateral border of foot
• medial and lateral plantar nerves (from tibial N) supply sole of foot.
• saphenous nerve supples medial border of foot.
• deep peroneal nerve supplies 1^stdorsal web space
• superficial peroneal nerve supplies majority of dorsum of foot.
• Posterior malleolus is the attachemnet site for the posterior talofibular ligament.

Lateral Malleolus Fracture Clinical Evaluation

• Ankle pain and swelling, inability to ambulate.
• Evaluate soft tissue injury and for open fractures.
• Document neurovascular exam before and after any treatment.
• Document whether tender medially or not(bimalleolar equivalent)
• Check for proximal fibular tenderness

Lateral Malleolus Fracture Xray

• A/P, Mortise(A/P in 20 IR), lateral.
• full length tib/fib films if proximal fibula is tender to evaluate for Maisonneuve fracture.
• fibular shortening by looking for a step in the alignment of the subchondral plates of the tibial plafond and the lateral malleolus.
• lateral malleolar SER type fx’s should be evaluated with Stress radiographs to determine stability of Deltoid ligament
• Stress radiograph:  leg stabilized in 10 degrees IR to obtain mortise view.  With ankle in neutral dorsiflexion an 8=10lb ER force is applied to the ankle.  Positive finding is medial clear space of >4mm and >1mm greater than the superior joint space or any lateral tibial subluxation.  ORIF indicated for positive stress  radiograph.  (McConnell T, JBJS 2004; 86A;2171). Gravity stress radiographs may be equally as sensitive with less pain.
• talocrural angle = 83 +/- 4, lesser or greater indicates instability or displacement of the mortise.  Angle is formed by lines drawn along tibial plafond and a line drawn along the tips of both malleoli.
• the space between the medial wall of the fibula and the incisural surface of the tibia should be <5mm.  Anterior tubercle of tibia should overlap fibula by at least 10mm.
• joint space from between talus and plafond should equal space medial malleolus and medial talus.  Widening of medial space indicates mortise displacement.
• lateral view demonstates fibular fracture pattern and anterior or posterior displacement of talus.
• tibiofibular distance should be 3.7mm =/- 0.5mm, 1cm above the joint.
• Based on radiographic evaluation, Harper and Keller found the clear space width the most reliable for detecting syndesmotic widening.  The clear space is the distance between the lateral border of the posterior tibia and the medial fibular border measured 1 cm above the tibial plafond on AP and mortise radiographs. Amendola A:  Controversies in diagnosis and management of syndesmosis injuries of the ankle.  Foot Ankle 1992;13:44-50
• Occult ankle fx suspected if total joint capsule distention (ant + post on lat view ) is 15mm.  PPV = 83%, sensitivity  = 86%.  CT if occult fx suspected.

Lateral Malleolus Fracture Classification/Treatment

• Isolated Lateral Malleolus Fracture
  -Weber A (below ankle joint level): Treatment = perfrom stress views/exam to eval for Syndesmosis injury(uncommon). If stable: walking cast/brace. Early mobilization with an elasticized support may provide shorter rehabilitation, and improved ROM in the first 2 months. (Port AM, JBJS 1996;78B:568).
  -Weber B (at level of ankle joint): Treatment = perfrom stress views/exam to eval for Syndesmosis injury. If stable: walking cast/brace. Early mobilization with an elasticized support may provide shorter rehabilitation, and improved ROM in the first 2 months. (Port AM, JBJS 1996;78B:568). If unstable: ORIF +/- syndesmotic fixation.
  -Weber C (above level of ankle joint): Generally unstable. Treatment: ORIF with syndesmotic fixation.
• Bimalleolar
  -Treatment = ORIF.
• Trimalleolar- ORIF fix posterior malleolus if >25% of plafond (Scheidt, J Trauma 1992;6:98), Strongly consider CT scan to determine posterior malleolar fracture size.
• Syndesmosis injury:if medial clear space increases with external rotation stress, or fibula fx >4.5cm above joint; ORIF of ankle fracture, fix syndesmosis in dorsiflexion with fibula reduced into incisura fibularis, HWR after 12 wks.
• AO-Webber classification
• Type A: transverse failure of lateral malleolus, at or just below the level of the ankle joint. (Suppination/adduction)
• Type B:typically oblique fx of lateral malleolus at level of mortise extending proximally from anterior to posterior.  Progressive talar ER causes injury to posterior syndesmotic ligament or fx of posterior malleolus.  Continued ER causes failure of medial complex.(supinnation/ER)
• Type C: medial side fails first, followed by anterior syndesmotic ligament then posterior syndesmotic ligament, then fibula fracture above mortise. (pronation/ER)
• Lauge-Hansen Classification
  Supination-external rotation(40-75%) (4 stages)-(1)rupture of anterior tibiofibular ligament; (2)spiral oblique fracture of the distal fibula; (3)fx of posterior malleolus or rupture of posterior tibiofibular ligament; (4)rupture of deltoid ligament or fracture of medial malleolus.  Up to 90% good results with ORIF
  Supination-adduction (2 stages)(10-20%)-(1)rupture of calcaneofibular ligament or transverse fracture of lateral malleolus; (2)fracture of medial malleolus
  Pronation-abduction(5-21%)(3 stages)-(1)rupture of deltoid ligament or transverse fx of medial malleolus; (2)rupture of anterior and posterior tibiofibular ligaments with or without a fragment of posterior tibia; (3)short, horizontal oblique fx of fibula just above the level of the ankle joint
  Pronation-external rotation (7-19%)4 stages-(1)fracture of medial malleolus or rupture of deltoid ligament; (2)rupture of anterior tibiofibular ligament and interosseous membrane; (3)short spiral oblique fracture of the fibula above ankle joint; (4)rupture of posterior tibiofibular ligament or fx of the posterolateral tibia.
  Controversion: mechanism have come into question recently. (Haraguchi N, 2009;91A:821).
• Volkmann's fracture=fracture of the posterior articular lip of the tibia.
• Reduction: should be performed as soon as possible to decrease potentials for presure ischemia, vascular compromise or articular injury. Done under conscious sedation or local hematoma block. Ankle block = 12ml 1% lidocaine; 20-gauge needle inserted just medial to the tibialis anterior tendon at the level of the ankle joint (White BJ, JBJS 2008;90A:731).
• Ankle ORIF Technique
• Diabetic Ankle Fracture
• Patient Guides: AAOS,

Lateral Malleolus Fracture Associated Injuries

• Tibiotalar articular-surface injury: 60%
• Syndesmosis injury (Boden SD, JBJS 1989;71A:1548).
• Anterior process of the calcaneous
• Lateral process of the talus
• Base of fifth metatarsal

Lateral Malleolus Fracture Complications

• Soft tissue/skin slough <3%
• Nonuion, medial malleolus most common, rare overall
• Malunion, loss of fixation
• Infection<2%
• Postraumatic arthritis10% if anatomic reduction, 90% if malreduced
• Tibiofibular synostosis, rare
• Painful hardware
• CRPS
• DVT / PE
• Diabetics with comorbidities have higher complication rates; significantly higher in-hospital mortality rate, in-hospital postoperative complication rate, length of stay, and rate of nonroutine discharges. Complications include impaired wound healing, infection, malunion, loss of reduction, hardware failure, nonunion, and Charcot arthropathy (Jones KB, JBJS 2005;87Br:489), (Chaudahary SB, JAAIS 2008;16:159).
• We discussed the risks of surgery including, but not limited to: incomplete relief of pain, incomplete return of function, nonunion, malnunion, painful hardware, compartment syndrome, CRPS, DVT/PE and the risks of anesthesia including heart attack, stroke and death.

Lateral Malleolus Fracture References

1. Rockwood and Greens
2. Petrisor BA, JOT 2006;20:515
3. Stiehl JB: Ankle fractures with diastasis, in Greene WB (ed): Instructional Course Lectures XXXIX.  Park Ridge, IL, American Academy of Orthopaedic Surgeons, 1990, pp 95-103.
4. Phillips WA, Schwartz HS, Keller CS, et al: A prospective, randomized study of the management of severe ankle fractures.  J Bone Joint Surg 1985;67A:67-78.
5. Weber BG and Simpson LA; Corrective lengthening osteotomy of the fibula.  Clin Orthop 1985, Oct; (199)61-7.
6. Yablon IG and Leach RE;  Reconstruction of malunited fractures of the lateral malleolus.  JBJS 1989, April; 71-A, No. 4, pp. 521-527.
7. Weber D, Friederich NF, Muller W:  Lengthening osteotomy of the fibula for post-traumatic malunion:  Indications, technique and result.  Int Orthop 1998; 22:149-152
8. Michelson, Fractures about the ankle (Current Concepts Review), JBJS Am, 77(1):  142-152, 1995.
9. VanderGriend et al., Fractures of the ankle and the distal part of the tibia, JBJS Am, 78(11):  1772-1783, 1996.
10. Boytim MJ, Fischer DA, Neumann L: Syndesmotic ankle sprains.  Am J Sports Med 1991;19:294-298.