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Open reduction and internal fixation of an open intra-articular distal femoral fracture with Synthes LCP distal femoral plate

    Overview

    Learn the Open reduction and internal fixation of an open intra-articular distal femoral fracture with Synthes LCP distal femoral plate surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Open reduction and internal fixation of an open intra-articular distal femoral fracture with Synthes LCP distal femoral plate surgical procedure.
    Distal femoral fractures account for around 6% of all fractures. They have a bimodal distribution, occuring in elderly patients following low energy injuries and in younger patients following high energy trauma such as road traffic accidents or falls from significant height. In older patients fractures around knee replacements (peri-prosthetic) or between ipsilateral hip and knee replacements (inter-prosthetic) are increasingly seen and implants specifically to deal with these challenging fractures have been developed.
    Approximately half of all distal femoral fractures are intra-articular and this has a significant influence on the chosen approach to fixation and the method of fixation. The final outcome after a distal femoral fracture will depend on the severity of articular injury, disruption of the mechanical axis and the extent of the soft tissue injury with poorer outcomes occurring in those with inadequately restored joint surfaces, residual mechanical axis deviation or stiffness secondary to scarring around the knee or extensor mechanism resulting in knee stiffness. It should also be appreciated that these are not benign injuries and in the elderly mortality after these injuries is similar to that seen after hip fractures.
    The majority of distal femur fractures will be surgically stabilised to restore joint anatomy and allow early mobilisation of both the knee joint and the patient. There are a number of fixation options, these include intra-medullary nailing with a retrograde technique, lateral plate with a condylar screw or blade plate, lateral plating with a locking plate or a medial buttress plate. The choice of implant will depend on the fracture pattern and the planned approach to fracture.
    The Synthes LCP distal femoral plate is a development of the LISS (Less Invasive Stabilisation System) range. It has multiple locking screw options in the distal segment allowing for fixed angle stabilisation around the joint, where screw purchase in bone may be less reliable. As long as the correct surgical steps are followed and attention is paid to the positioning of the plate during fixation coronal and sagittal alignment can be reliably restored. The plates come in a variety of lengths and for proximal screws there are now locking and non-locking screw options, giving the surgeon adequate flexibility when planning fixation.

    Indications

    INDICATIONS
    Open fractures can be considered as soft tissue injuries complicated by fracture, and as such skeletal stabilisation is required to allow the soft tissue envelope to heal. Definitive fracture fixation is performed at the same time as definitive soft tissue closure or coverage.
    Distal femoral fractures can occur following high energy trauma in younger patients or following lower energy injuries in elderly patients with poor bone stock. We are seeing increasing numbers of peri-prosthetic fractures above knee replacements. Surgery is indicated in the majority of cases to restore the articular anatomy and the overall limb alignment and to allow early mobilisation of the patient which is particularly important in the older patient in whom these fractures should be considered as analogous to neck of femur fractures with similar time frames to surgery.
    SYMPTOMS & EXAMINATION
    Younger patients will often present as multiply injured patients and should be assessed by the receiving trauma team according to an ATLS/ETC framework.
    Open lower limb fractures present with limb deformity and an overlying traumatic wound. it is important to know the environment that the injury occured in (to guide likely contaminants, farmyard or marine contamination being highly significant). Examination focusses on documenting the traumatic wound, photos are taken and then the wound is covered with a saline soaked gauze and not disturbed again. The neurovascular status should be documented and signs of compartment syndrome checked for. Following examination the limb should be splinted in alignment and a neurovascular examination repeated.
    IMAGING
    Plain X-Ray films of the femur together with CT scan of the fracture site to help guide the articular reconstruction.
    The CT scan can be used to classify the articular component into type A (extra-articular), type B (partial articular, often amenable to stabilisation with buttress plating) and type C (complete articular with total loss continuity of the joint and femoral shaft). It should also be scrutinised for other injuries around the knee, including tibial plateau fractures and the presence of a Hoffa fragment- this is a coronal split of the femoral condyle present in up to 1/3 of type C fractures which may necessitate a separate approach to achieve reduction and stabilisation.
    ALTERNATIVE OPERATIVE TREATMENT
    Severely injured patients not fit enough to undergo definitive fixation can be temporised with a spanning external fixator to stabilise the femur and aid their resuscitation. This can then be exchanged for definitive internal fixation once the patients physiology has recovered. The change from external to internal fixation should ideally occur within 2 weeks to avoid the risks of deep infection secondary to external fixator pin sites.
    Many distal femur fractures, including some intra-articular patterns with simple articular splits, can be treated with intra-medullary nails. Nails are indicated in most extra-articular fractures although care must be made when assessing the pre-operative imaging that there is sufficient bone stock in the distal fragment to achieve adequate purchase and stability with the distal locking bolts of the nail- knowledge of the specification of ones chosen nail is essential. Intra-articular fracture with simple splits that can be stabilised with compression screws creating a distal block large enough for the locking bolts of a retrograde nail to gain sufficient purchase can be managed with intramedullary nailing.
    Most intra-articular fractures of the distal femur will be stabilised with plates, often augmented with screws, positioned outside the plate, to compress and main articular fragments. Plates utilising condylar screws or blades have largely been superseded by locking plates although they still have their place. The commonest type of plate now used is the lateral locking plate, this allows fixation of the distal femur via a safe approach, locking screws provide a fixed angle construct with increased pull-out strength compared to normal screws. These plates are not without their problems however, this includes malunion (typically into valgus and external rotation) and an inability to stabilise the medial column which may lead to varus instability in fracture patterns with medial side comminution or bone loss- in which case augmentation with a medially positioned plate inserted via a subvastus approach may be indicated.
    In some severe injuries with very complex articular involvement the option of endo-prosthetic distal femoral replacement may be considered and all such injuries should be discussed with a unit experienced in such techniques.

    Setup

    The patient is positioned supine on a radiolucent table to allow image intensifier access to the whole limb. Antibiotic prophylaxis should be given on induction of anaesthesia according to local or national guidelines for open fractures. The limb is first given a ‘social wash’ with soap solution to remove debris from the skin. The whole limb is then prepped with alcoholic chlorhexidine, although this should not be used within the traumatic wound itself. Drapes are applied leaving the entire limb from proximal femur to foot exposed.
    It is useful to place a bump behind the knee to give slight flexion and thereby relax the gastrocnemius which tends to cause the distal femoral fragment to extend. Tourniquets are not used.

    Operation – 1

    Trauma CT scanogram showing a distal femoral fracture with a healed previous fracture of the proximal femur with a resultant malunion.
    The combination of of an intra-articular distal fracture and with a malunion above it makes nailing of this injury extremely challenging and a lateral distal femoral plate is the treatment of choice for this situation.

    Pre-operative CT scan demonstrating intra-articular fracture with metaphyseal comminution
    The CT images are studied in all planes to build a mental picture of the fracture and to plan the fixation. Here, axial images demonstrate metaphyseal comminution and an antero-posterior articular fracture extending into the patellofemoral joint. The coronal and sagittal images confirm that the joint is completely separated from the rest of the femur making this a C-type fracture.

    The traumatic wound is extended longtitudinally to allow delivery of the bone endsThe first part of the operation is debridement of the traumatic wound and is often performed jointly with a plastic surgeon.

    Wound extensions are performed along fasciotomy lines (demonstrated by the marked dotted lines), this will allow access to the fracture and excision of the traumatic wound.

    Wound debridement proceeds in a stepwise fashion with debridement of each layer of tissueAs debridement proceeds through each tissue layer, all non-viable tissue is excised to leave only clean healthy tissue.

    The proximal and distal bone ends are delivered into the wound In all open fractures the wound must be extended sufficiently to allow delivery of bone ends (1.) so that adequate bone dedridment can be performed. Here Hohman retractors and a bone hook have been used to gently deliver the proximal end of the fracture.

    The bone ends are debrided back to healthy bone and any loose, non-viable, fragments of bone are removed.Currettes and bone nibblers are used to carefully debride the bone ends. Punctate bleeding is a sign of healthy viable bone.

    Loose bone fragments are assessed using the ‘tug test’, gentle traction with a surgical instrument. Those that fail this test do not have soft tissue attachments, are non-viable and a potential nidus for infection, these should be removed. In cases with significant bone loss this may require reconstruction. Contained metaphyseal defects can be reconstructed with interval grafting or a Masquelet technique where a bone cement spacer is left in the bone defect to stimulate membrane formation and then replaced with autologous bone graft at around 6 weeks.

    Following debridement the wound and bone are thoroughly lavaged with salineFor most open fractures this will be minimum of 6 litres, this should be infused through a standard giving set rather than with pulse lavage (which risks seeding contamination to deeper tissue planes).

    Once the debridement has been completed it is possible to classify the fracture.
    The most commonly used classification system is that described by Gustilo and Anderson.
    Grade 1 injuries have a wound less than 1 cm with minimal soft tissue injury or contamination, grade 2 injuries have more extensive soft tissue injury but the wound is less than 10cm. Grade 3 open fractures are high energy injuries with wounds over 10cm, extensive soft tissue injury and periosteal stripping. All segmental fractures are grade 3. Grade 3B injuries require complex soft tissue reconstruction (local or free flap) and 3C injuries have a vascular injury requiring repair.

    Once the open fracture debridement and lavage is complete the limb is re-prepped and draped and fresh gowns and gloves are donned.The operation now moves from the contaminated phase to the clean phase therefore the limb is re-prepped and draped and clean instruments should be available.

    The knee joint and fracture are marked on the limb using the image intensifier.

    Fracture stabilisation begins with exposure of the articular component using a ‘swashbuckler ‘ approach to the antero-lateral distal femurThis approach allows good visualisation of the knee joint and access to the lateral aspect of the distal femur for positioning of a lateral plate.
    Approaches to the lateral femur are generally safe although posterior perforating branches of the vastus lateralis may be at risk if the muscle is elevated more proximally.

    The swashbuckler approach starts with a skin incision from the lateral aspect of the tibial tubercle to the supero-lateral aspect of the patella. the incision can then be curved proximally and inferiorally to facilitate access to the lateral aspect of the distal femur.
    The patella retinculum is then incised along the lateral border of the patella tendon, the incision curves around the lateral aspect of the patella leaving a cuff of tissue to repair at the end of the procedure.
    As the deep dissection extends proximally the plane deviates inferiorly along the distal border of the vastus lateralis which can be mobilised to access the distal femur laterally. The patella and extensor mechanism are then mobilised medially to expose the articular surface of the distal femur.

    The articular surface of the femur is exposed and the fragments gently cleared of haematoma The main articular split has been exposed (1) and is carefully cleared of haematoma and debris, using a 20ml syringe and a drawing up needle, prior to reduction.

    The articular fracture is reduced and compressed with a peri-articular clamp prior to fixation.The joint surface requires anatomical reduction, this is achieved under direct vision. Once achieved reduction can then be held by several methods, here I have used a peri-articular clamp to hold the reduction which has the added benefit of applying compression across the fracture.

    Fracture reduction is first confirmed under direct visualisation

    Fracture redcution is then confirmed on AP and lateral II images and screw positioning plannedScrews to compress the articular fragments will be placed indepent of the plate, their position should be carefully planned to avoid the plate (usually anterior and distal) and to avoid joint penetration

    The articular fracture is then stabilised with 4.5 mm cortical screws in a lag mode to apply compression Having achieved an anatomical reduction we then fix the fracture with absolute stability to achieve primary bone healing. This can be achieved with partially threaded cancellous screws or cortical screws in a lag mode with overdrilling of the near side of the fracture.
    Two or three large fragment screws are sufficient in most cases. Care should be taken to position the screws so that they do not compromise the position of the plate which will be used later to stabilise the metaphysical component of the fracture.

    My own preferred technique is to use 4.5 mm cortical screws engaging 2 cortices in a lag mode.
    First a 3.2mm drill is passed, via a 4.5mm drill guide, across the fragments under image intensifier guidance. The drill guide is left in position while the drill bit is exchanged for a 4.5mm size, this is then used to over-drill the near fragment. As the screw is tightened inter-fragmentary compression is achieved. Use of the countersink, as shown, further helps to prevent the screws compromise plate positioning later in the procedure.

    The correct length femoral plate is selected and mounted on the jig or with a screw-in drill guideOnce the articular component is stabilised the next stage is to fix this to the rest of the distal femur.
    The metaphyseal component of the fracture is often multi fragmentary and is stabilised with relative stability. In this case I have opted to use a lateral locking plate to achieve this.
    The synthes distal femur LCP can be inserted mounted on a jig, as shown, which has the benefit of making placement of the proximal screws easier although the weight of the jig tends to externally rotate the construct and can make both imaging and positioning of the implant more difficult. First the plate is placed on the jig.

    Next the fixation bolt is used to attach the jig to the A-hole of the plate, this is the central hole in the distal grouping of screw holes.
    It is the key landmark for aligning the plate to the distal femur. Its’ position is marked on the jig.

    The fixation bolt is then tightened in place.

    Once the jig is attached to the plate it can be used to insert the plate along the femur and then to insert the screws via the guide holes on the jig (1).
    The plates come in a range of lengths that allow the whole bone to be spanned if needed. The plates have a good anatomic fit and rarely, if ever, need to contoured for primary fracture fixation cases- if it doesn’t fit the bone it is likely that the fracture is not reduced adequately.
    I have opted to use a long plate to give a good span of the bone, proximal fixation will be spread along the length of the plate to achieve relative stability and avoid a too rigid construct.
    The nuts on the jig (2.) mark the most proximal end of the plate and can be tightened to stabilise the wire guides for proximal plate positioning.

    Alternatively the plate can be inserted using a screw-in drill guide as shown. The guide has been placed in the A-hole of the plate, this will be to confirm that the plate is correctly aligned once is is positioned.

    Operation – 2

    The plate is inserted through the lateral incision and slid beneath the vastus lateralisRather than use the jig I have used a screw-in drill guide to control the distal end of the plate while it is slid over the periosteum and beneath the muscles laterally via the distal wound.

    The plate is provisionally secured at the distal end with a k-wire inserted through a guide screwed into the A-hole of the plateThe plate position is checked on AP and lateral xrays. The wire should appear parallel to the joint in the AP image which indicates correct alignment of the plate and that once seated proximally the coronal alignment should be restored. Note that the plate appears to sit anteriorly and internally rotated by approximately 10 degrees on the distal femur when correctly seated on the bone.

    The plate is provisionally secured to the proximal femur with a wire under image control, length and rotation of the limb are checkedThe plate position is first checked on AP and lateral images and then an incision made over the proximal end of the plate. A femoral distractor may be used to restore limb length if required. The plate can then be positioned in the desired location on the proximal femur and held in place with a k-wire.

    Distal fixation of the plate is performed with locked screws Locking screws provide a fixed angle construct with increased pull out strength and are indicated in peri-articular bone, osteoporotic bone or peri-prosthetic fractures. The screw holes are drilled via guides screwed into the plate and the screws placed under image control. Screw length can be measure directly from the drill bit using the attached marker (1.)

    Distal fixation is completed and checked on image intensifierOnce distal fixation is completed the overall length and alignment of the limb is re-checked clinically and radiologically before proceeding to proximal fixation.

    The distal position on lateral imaging is checked ensuring that no metalwork is within the jointThe trochlea floor (1, this represents the anterior distal femur and the femoral part of the patella-femoral joint) and Blumensaats line (2, the roof of the inter-condylar fossa) are checked on the lateral view to ensure no joint penetration.

    In this patient there were no concerns regarding bone quality and cortical screws were used. These are inserted under image control.
    Proximal fixation can be achieved with locked or cortical screws depending on the indications and the quality of the bone
    I am aiming to achieve relative stability at the metaphyseal fracture and it is important to avoid making the construct too rigid, I therefore used a long plate with 4 bi-cortical screws spaced out over the length of the plate rather than a shorter plate with all the screw holes filled. The latter will result in a stiffer bone-implant construct that splints apart non-anatomically reduced fragments and can result in non-union.

    The proximal screws are inserted through small incisions, with locked or cortical screws depending on the indications and the quality of the boneThe proximal screws are inserted through small incisions, care is taken to avoid soft tissue stripping around the fracture thereby preserving the fracture biology and aiding bone healing.
    The combi-holes in the proximal segment of the plate do allow compression with a cortical screw in the non-locking part of the hole. The metaphyseal segment of the fracture rarely needs anatomic reduction or absolute stability, however, and it is rarely necessary to apply compression through the plate.

    The metaphyseal segment has been spanned with minimal disruption to preserve the fracture biology while restoring limb length, alignment and rotation.
    Final check images are taken.

    Final lateral imaging. Four bicortical screws have been used in the proximal segment, this should be sufficient for immediate weight-bearing in most cases. If following lateral plate fixation the fracture is not deemed sufficiently stable (often due to marked medial comminution not controlled from the lateral side) then consideration should be given to augmentation with a medial plate inserted via a sub-vastus approach to allow early mobilisation.

    Wound closure is performed in a layered fashion with interrupted suturesFollowing final images and thorough lavage of the wounds, a layered closure is performed with interrupted sutures to each layer including skin.

    The wounds are dressed with a non-adherent dressing, I prefer Jelonet, and a bulky bandage applied.

    Post Operative

    It is important to get the knee moving immediately post-operatively under the supervision of the physiotherapy team.
    This patient group will require a period of prolonged VTE prophylaxis according to local protocol.
    Early weight bearing as tolerated is encouraged in most patients and is vital in elderly patients to avoid prolonged immobility or bedrest. A more cautious approach to weight bearing may be taken in those with complex articular injuries. Most patients should aim to be mobilising independently by 3 months.

    Recommended Reading

    Beltran MJ1, Gary JL, Collinge CA. Management of distal femur fractures with modern plates and nails: state of the art. J Orthop Trauma. 2015 Apr;29(4):165-72.
    This article gives an overview of distal femoral anatomy, fracture patterns and options for stabilisation.
    Dugan TR1, Hubert MG, Siska PA, Pape HC, Tarkin IS. Open supracondylar femur fractures with bone loss in the polytraumatized patient – Timing is everything! Injury. 2013 Dec;44(12):1826-31.
    Beltran MJ1, Gary JL, Collinge CA. Management of distal femur fractures with modern plates and nails: state of the art. J Orthop Trauma. 2015 Apr;29(4):165-72.
    This article gives an overview of distal femoral anatomy, fracture patterns and options for stabilisation.
    Dugan TR1, Hubert MG, Siska PA, Pape HC, Tarkin IS. Open supracondylar femur fractures with bone loss in the polytraumatized patient – Timing is everything! Injury. 2013 Dec;44(12):1826-31.
    Case series describing a protocol for the management of high energy grade 3 open distal femur fractures. The first stage involved lateral locking plate and cement beads to the bone defect. The second stage, after several months, consisted of bone grafting and medial column plate fixation .
    W. E. C. Poole, D. G. G. Wilson, H. C. Guthrie, S. F. Bellringer, R. Freeman, E. Guryel, S. G. Nicol.
    ‘Modern’ distal femoral locking plates allow safe, early weight-bearing with a high rate of union and low rate of failure five-year experience from a United Kingdom major trauma centre. The Bone & Joint JournalVol. 99-B, No. 7
    Large series of distal femur fractures managed with lateral locked plates demonstrating high union rates (95%) with low incidence of re-operation (3%) and no adverse outcomes associated with immediate weight bearing.

    Reference

    • orthoracle.com

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