Ankle Fracture: Tips and Tricks

Transcription

1 Ankle Fracture: Tips and Tricks Christiaan N. Mamczak, DO LCDR, MC, USN Naval Medical Center Portsmouth Department of Orthopaedic Surgery Assistant Professor Uniformed Services University of the Health Sciences

2 Disclosures Member OTA Disaster Preparedness Committee AONA Orthopaedic Trauma Faculty The views expressed in this article are those of the author and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government. Thanks to AONA and OTA lecture archives

3 LEARNING OBJECTIVES 1. Critically evaluate radiographs and recognize when CT imaging will help pre-operative planning 1. The importance of fibular length 2. Technical tricks for reduction and fx fixation 3. Recognize articular pathology in SAd and PAb fractures When to consider posterior malleolar fixation 1. Why syndesmotic reduction is not that easy

4 Radiographic Scrutiny Critical Radiographic Measurements : MCS Widening Fibular length Mortise dime sign

5 DOME LATERAL VIEW Critical Lines to assess: Medial malleolar anatomy Supracollicular fx ORIF vs. AC fxs non-op (Tornetta et al. Paper #60; OTA Annual Meeting 2011) Posterior malleolar status Talar subluxation w/ PM fx Fibular position vs. tibial pafond Syndesmotic relationship P A

6 Ancillary imaging Stress Views CT / MRI Both effective to detect medial clear space widening. Michaelson et al CORR 2001 Schock et al JBJS 2007 CT: fxs MRI: articular impaction posterior malleolar syndesmotic injury, deltoid competence, talar OCL

7 Critical factors to ankle stability 1. Fibular length/rotation 2. Articular congruity 3. Ligamentous Integrity

8 Importance of Fibular length Restoration of length to the fibula is an absolute priority. Surgical complexity s with fracture comminution and osteopenia Weber Int. Orthop 1981 Fibular shortening >2mm, lateral shift >2mm and ER >5 negatively alter midlateral and PL talar dome contact pressures Thordarson et al. JBJS 1997

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10 Fibular comminution Common in SER, PER and PAd fracture patterns Pronation-Adduction Fx Critically review injury XR Operative plan: - Can t always lag the fragments - Respect the periosteum - Extra-periosteal Bridge plating techniques ensure fx union Siegel/Tornetta JBJS 2007; Ebraheim et al. FAI 1987

11 The Push-pull screw Powerful mechanical advantage Lengthening w/ laminar spreader Compression w/ Verbrugge

12 Effect of Fibular length on Ligamentotaxis

13 Working distance is important

14 S-Ab Articular involvement Lateral Injury: transverse fibular fracture at/below level of mortise Medial injury: vertical shear type medial malleolar fracture BEWARE OF MARGINAL IMPACTION POTENTIAL BONE GRAFTING! McConnell et al. J Orthop Trauma 2001

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16 S-Ab Medial mal fixation Analysis of Fixation Methods for Vertical Shear Fractures of the Medial Malleolus Dumigan et a. J Othop Trauma Buttress plate is mechanically superior to screw only constructs

17 More on Medial mal fixation Non-vertical MM fx fixation Ideal construct should: - provide compression - achieve fracture union - not generate ST pain - lead to good clinical outcomes

18 Why not lag by technique? Industry Constraints: - Screw lengths are inadequate in most current implant sets to allow lag by technique - Bicortical lag screw vs. PT lag screw: - 3x greater torque before stripping - less radiographic loosening - improved clinical outcomes

19 P-AD articular injury Medial injury: transverse to short oblique medial malleolar fracture - Tension side injury- consider fixing 1 st to stabilize mortise Lateral Injury: comminuted impaction type lateral malleolar fracture -BEWARE OF OCCULT CHAPUT FX (Consider CT scan)

20 Chaput fx & comminution

21 Re-defining the importance of the Posterior malleolus CORONAL OBLIQUE FX Best visulaized on ER lateral XR [Decoster FAI 2000] Indication for fixation: 25-33% size debatable Posterior instability = d stress anteriorly = post-traumatic arthritis Articular step off >2mm r/o Intercalary fragment blocking ligamentotaxis *fibula and anterior tibiofibular ligament act as primary restraint [Raasch JBJS 1992] **contact stress changes significantly with posterior malleolar size >33% [Hartford CORR 1995]

22 PM Fx Represents: Articular Injury and Ligamentous Instability 67% 19% Haraguchi et al. JBJS 2006 Type I- posterolateral oblique type 14% Type II- medial extension type Type III- small shell type

23 The Role of Pre-op CT scan on operative planning and fixation of ankle fxs (Black et al. Poster #50 OTA Annual Meeting 2012) Operative plan changed 24% Most common operative changes: Medial malleolar fixation 21% Posterior malleolar fixation 15% Occult Chaput plafond fx 9% CT most influential with: Trimal fxs Fx-Dislocations Preop XR obscured by plaster Supra-syndesmotic fxs

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25 Value of pm fixation Posterior Malleolar stabilization of syndesmotic injuries is equivalent to syndesmotic fixation (Miller et al. CORR 2010) Fixation of the posterior malleolus provides greater syndesmotic stability (Gardner et al. CORR 2006)

26 PM fixation can prevent syndesmotic screw

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28 Posterolateral Approach FHL-Peroneals Sural NV bundle Peroneal Artery Posteromedial Approach Thru PT tendon sheath Mobilize b/w tendons PT NV bundle

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30 Ligamentous integrity MCS Widening: SER-2 vs. SER-4 Eq - Deltoid Injury ± -Syndesmotic Injury ~40-47% of SER-4 equivalent fractures (Tornetta et al. JOT 07, 12) Stress View Splintage

31 assumptions 1. Fibular fractures associated with a stable ankle mortise heal without significant functional consequence. 2. Fibular fractures associated with an unstable ankle mortise heal with significant functional problems because instability allows for talar shift. Does a Stress Positive Ankle (i.e. SER-4 equiv) Indicate the Need for Operative Treatment? NOT NECESSARILY 19/21 SER-4Eq had incomplete deltoid injury on MRI Good functional and radiographic outcomes with non-op treatment Koval et al. J Orthop Trauma 2007

32 Syndesmotic Integrity Injury patterns include continuum: LIGAMENTOUS BONY Leads to: Wide medial clear space (>4mm) AP tib-fib overlap (<6-10mm) AP tib-fib clear space (>5mm) Always stress EVERY ANKLE! Pre-Op & Intra-Op

33 Syndesmotic reduction 16-52% malreduction rate! Intra-op radiographs unreliable Most are anterior ± ER Over-compression is common Clamps/screws contribute to malreduction WORSE OUTCOMES Gardner et al. Foot Ankle Int 2006, Hovis et al. JBJS Am 2002, Sagi et al. J Orthop Trauma 2012, Elgafy et al. Skel Rad 2010, Miller et al. J Orthop Trauma 2012, Leeds et al. JBJS Am 1984, Weening et al. J Orthop Trauma 2005, Sagi et al. J Orthop Trauma 2012 Crescent 67% Rectangular 33%

34 Improving reduction Comparison views of un-injured ankle Summers et al. JOT 2012 Strategic clamp and screw placement Miller et al. JOT 2012 Clamps at 0 to syndesmotic joint Lateral screws at 0 better than P to A Posterolateral screws at 30 better than 15

35 Reliable reduction

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37 Hardware Removal? Trend towards benefits of screw removal: 1. Manjoo et al. J Orthop Trauma 2010 Better functional results w/ ROH if rigidly fixed & restricted DF No difference if loose screws or broken screws with good ROM 2. Miller et al. J Orthop Trauma 2010 Increased ROM, better FAOS and Olerud/Molander scores 3. Song et al. OTA Paper # Annual Meeting Minneapolis, MN 32% malreduction rate 87.5% of malreductions reduced on postop CT 30 days after ROM

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