Cephalomedullary Nailing of the Proximal Femur

DEFINITION

• Fractures of the proximal femur are usually grouped into four major types reflecting differences in the anatomic and physiologic character of these regions:

  • Femoral head fractures

  • Intracapsular femoral neck fractures

• Pertrochanteric fractures (also referred to as intertrochanteric and peritrochanteric), which include proximal extracapsular fractures of the femoral neck region to the region along the lesser trochanter before the development of the medullary canal

  • Subtrochanteric fractures

• Cephalomedullary nailing is the surgical stabilization of the fracture with an intramedullary device usually inserted through the piriformis fossa, the lateral greater trochanter, or the medial greater trochanter.

  • The cephalic or femoral head portion of the fixation construct is one or more screw or blade devices interlocked with the nail component of the construct.

Cephalomedullary nails are most commonly indicated in extracapsular peritrochanteric and subtrochanteric fractures. Although there is occasional overlap of these regions, the personality of the fracture will be predominantly one of these major types.

ANATOMY

• The transitional anatomy from the femoral head to the subtrochanteric region affords very different fracture pathogene-ses, affecting the surgical opportunity for repair.

  • Intracapsular fractures of the femoral neck are critically dependent on the vascular supply from the medial femoral circumflex artery for fracture repair and maintenance of vascularity of the femoral head to avoid avascular necrosis.

  • Conversely, the well-vascularized pertrochanteric region is dependent on the structural integrity of an essentially solid cancellous bone block from the triangle of Ward to the lesser trochanter, where the solid nature of the structure changes to a tubular construct with the origin of the femoral medullary canal (FIG 1A).

• Subtrochanteric fractures incur the highest stresses in the proximal femur owing to their tubular anatomy, which places high degrees of stress on the implants used for their fixation.

The muscular attachments of the gluteus medius in the lateral aspect of the greater trochanter and the iliopsoas insertion in the lesser trochanter are key determinants in the deforming forces associated with fracture displacement and functional recovery after injury (FIG 1B).

PATHOGENESIS

• Fractures of the proximal femur fall into three mechanistic categories:

• Low-energy same-level falls, predominantly in the senior population (50 to 80 years), often associated with osteoporosis and muscular atrophy

• High-energy trauma in the 18- to 45-year age group from motor vehicle collisions and falls from greater heights, resulting in fractures with marked displacement and comminution

• Pathologic fractures, often the first indication of a neo-plastic process

NATURAL HISTORY

• To obtain any real hope of ambulatory recovery, surgical treatment is necessary for complete fractures, as the resulting deformity of a nonoperatively treated hip invariably results in significant shortening and varus deformity.

• Functional recovery is actually very poor despite surgical treatment of these fractures with conventional techniques in the 50- to 80-year age group.

  • The American Academy of Orthopaedic Surgeons estimates a 24% mortality rate in patients older than 50 within 1 year after fracture, and only 25% of patients make a full recovery.2

     

    PATIENT HISTORY AND PHYSICAL FINDINGS

• Pertinent history for a hip fracture patient focuses on the mechanism of injury for insight into the potential quality of bone available for repair and associated injuries in high-energy trauma.

• Associated injuries or premorbid diseases may coexist with the fracture diagnosis. Syncopal episodes resulting in a fall may bring attention to cardiovascular and neurologic disease states.

• A history of any tumor or malignant disease, including the last mammogram and breast examination in women older than 45 and the last prostate examination in men older than 40, may suggest an underlying pathologic etiology for the fracture.

• Drug use, either illicit or prescribed, as a confounding and contributing factor must be sought.

• Unfortunately, nursing home and institutionalized patients must be examined for potential neglect and abuse.

• The physical findings of a displaced hip fracture are shortening of the extremity, deformity of rotation compared to the contralateral extremity, and pain or crepitance with motion at the hip.

  • Shortening and rotational deformity may be the result of varus deformity at the hip from associated muscular pull or telescoping of 100% displaced fragments.

• Examination should also include the Lippmann test (auscul-tation). Decreased tone or pitch implies fracture. Sound conduction through the pelvis and hip from the pelvis is interrupted by any discontinuity from the patella, femur, or pelvis articulations.

FIG 1 • A. Radiographic anatomy of the proximal femoral fracture zones. Note greater trochanter and lateral wall and lesser trochanter and medial wall.

B. Muscle attachments in

subtrochanteric fractures accounting for the subsequent

deformity of the fracture. B

• Swelling and discoloration with hematoma are signs of injury but are usually not acutely present.

• Lacerations, Morel-Lavalle lesions, and decubitus ulcers may complicate the surgical approach.

Extracapsular proximal femur fractures extravasate blood into the surrounding tissues.

IMAGING AND OTHER DIAGNOSTIC STUDIES

• Plain radiographs, including an anteroposterior (AP) view of the pelvis, AP and cross-table lateral views of the affected hip, and AP and lateral radiographs, are required for diagnosis and preoperative planning.

• If a long nail implant is a consideration, AP and lateral radiographs of the affected femur to the knee are required, with special attention to femoral bow and medullary canal diameter.

• CT or MRI scans are rarely required for displaced fractures but may be useful in establishing the diagnosis in nonobvious fractures and atypical fractures in high-energy trauma patients.

• If a pathologic etiology is suspected, however, an MRI or PET scan of the body should be considered as part of the initial workup.

• Intraoperative or preoperative traction radiography or fluo-roscopic C-arm views may be helpful in delineating the extent of complex fractures.

• Intraoperative length measurements with the C-arm of the normal femur may be helpful in selecting the correct nail length in complex fractures (FIG 2).

  DIFFERENTIAL DIAGNOSIS

• Painful arthropathy (osteoarthritis, rheumatoid arthritis, septic)

• Established nonunion of the proximal femur

• Pathologic deformity (ie, Paget disease, fibrous dysplasia of the hip)

• Pubic rami fracture

• Acetabular fracture

• Contiguous femoral fracture

• Hip fracture-dislocation (rare)

  NONOPERATIVE MANAGEMENT

• Nonoperative treatment is frequently the best option in non-ambulatory or chronic dementia patients with pain controllable with analgesics and rest, patients with terminal disease with less than 6 weeks of life expected, patients with unresolv-able medical comorbidities that preclude surgical treatment, and patients with active infectious diseases that preclude insertion of a surgical implant.

  • An exception is incomplete pertrochanteric fractures diagnosed by MRI, which have been shown to heal with nonoperative measures in selective patients.1

     

     

     

    FIG 2 • Estimate of nail required from intraoperative radiograph of normal femur with nail in box.

     

    • Nonoperative management must include attentive nursing care with frequent positioning to avoid decubiti, attention to nutrition and fluid homeostasis, and adequate analgesia or narcotic pain suppression. Patients may be mobilized from bed to chair as tolerated, usually after 7 to 14 days, with careful support and elevation of the affected extremity.

    • Fracture callus at 3 weeks markedly decreases motion-related pain, and by 6 weeks most patients can be lifted into a wheelchair or reclining chair.

    • Ambulatory ability should not be anticipated after nonoperative treatment of displaced fractures.

      SURGICAL MANAGEMENT

    • Surgical management, once selected, should be performed as soon as any correctable metabolic, hematologic, or organ system instabilities have been rectified. Usually this is within the first 24 to 48 hours for most patients.

      • The literature is inconclusive as to increased mortality after this time, but patient suffering and hospital efficiencies demand timely intervention.

        Preoperative Planning

    • Standard AP pelvis and AP hip radiographs are usually obtained. Cross-table lateral and films in traction are useful if the hip fracture pattern is complex. Hip fractures are three-dimensional entities, and this is readily apparent in high-energy trauma cases. Full-length radiographs of good quality are required before surgery to evaluate the full extent of damage to the femur, to estimate the length and diameter of implant selections, and to avoid neglect of skip lesions or segmental damage to the femur.

    • Classifications for pertrochanteric and subtrochanteric hip fractures have not been particularly helpful in clinical situations, although increased surgical complexity is associated with unstable fracture patterns.5

      • Unstable characteristics include posteromedial large separate fragmentation, basicervical patterns, reverse obliquity patterns, and displaced greater trochanteric or lateral wall fractures.

      • The Evans, Kyle, AO/OTA, and Russell-Taylor classifications are commonly referred to in the literature.

    • The Russell-Taylor classification assists in implant selection for the proximal femur by drawing attention to the high-risk attributes of the proximal femoral anatomy, particularly the absence or presence of fracture extension into the greater trochanter (lateral wall), referred to as group I (intact greater trochanteric region) and group II (fracture extension), and secondly the absence or presence of medial cortical stability in the lesser trochanteric region, referred to as type A (stable contact possible) and type B (fracture instability) (FIG 3).17

      • Russell-Taylor type IA fractures are in reality high diaphyseal femoral fractures within 5 cm of the lesser trochanter and are preferentially treated with conventional interlocking nails. with the surgeon’s choice of either trochanteric or piriformis entry devices.

      • Russell-Taylor type IB fractures are fractures at the dia-physeal–metaphyseal junction of the proximal femur with medial instability due to fracture comminution. The greater trochanter and lateral wall are intact, and cephalomedullary nails, either of the reconstruction nail class or gamma nail class, are indicated, with either a trochanteric or piriformis entry type of device with the respective portal.

    • Russell-Taylor type IIA fractures are fractures involving the greater trochanter and lateral wall but have the possibility of restoration of medial cortical stability. Reverse obliquity patterns fall into this group. If the greater trochanter is displaced, open reduction and stabilization are required. Trochanteric portal cephalomedullary nails are recommended if a nail technique is preferred. Piriformis nails may not obtain sufficient stability of the proximal femur. Open plate and screw reduction with an indirect reduction technique may be preferred in this group of patients.

    • Russell-Taylor type IIB fractures are the most unstable fractures, with fracture extension into the greater trochanteric region, and have lost medial cortical stability. Trochanteric cephalomedullary nails are the preferred nail option for this group if a stable nail construct can be obtained, or alternatively a 95-degree angle plate and screws. These are very complex fractures to treat with nail techniques, and new locking plate designs may be advised in the future based on future clinical studies.

    • Reverse obliquity patterns and lateral wall fractures occurring in the perioperative period have been identified as

      

      FIG 3 • Russell-Taylor classification. Type IA fractures are in reality high diaphyseal femoral fractures within 5 cm of the lesser trochanter. Type IB fractures are fractures at the diaphyseal–metaphyseal junction of the proximal femur with medial instability due to fracture comminution. Type IIA fractures involve the greater trochanter and lateral wall but have the possibility of restoration of medial cortical stability. Type IIB fractures are the most unstable fractures, with fracture extension into the greater trochanteric region, and have lost medial cortical stability.

       

      high-risk patterns for sliding compression hip screw-type implant failure, with secondary displacement and failure to maintain the reduction. This calls into question our ability to differentiate stable from unstable pertrochanteric fractures.4,12

• Determination of the preoperative neck–shaft angle and medullary canal diameter is paramount to selection of the correct nail device, as different manufacturers have different neck–shaft angle and diameter nails. Another important consideration is nail curvature for long nails. Curved nails with a 1.5- to 2-meter radius are applicable to most situations, but the surgeon must beware of patients with excessive curvature or tertiary curves in the distal third of the femur, as distal penetration of long nails has been reported.10

• Cephalomedullary nailing involves fixation of the femoral head coupled with an intramedullary shaft implant (FIG 4).

  These implants are designed to have a piriformis portal for insertion, usually with the shaft component straight in the AP plane, or a trochanteric portal with the shaft component laterally angulated proximally.

  • Modern trochanteric designs have moved to a 4-degree proximal bend positioned above the lesser trochanteric region, which seems to be most compatible with anatomic restoration of the fracture.11

• Reconstruction design nails (two smaller screws into the head) (Russell-Taylor Reconstruction Nail, TriGen; Smith & Nephew) have the usual advantage of a smaller head diameter (average 13 to 15 mm) and may be of a piriformis or trochanteric portal design, whereas the traditional trochanteric portal (Gamma; Stryker-Howmedica), IMHS (Smith & Nephew) nails have a single large-diameter femoral

  

  FIG 4 • Cephalomedullary nail types from Smith & Nephew, Inc. A. Gamma Class IMHS. B. Piriformis TriGen Reconstruction Nail. C. Trochanteric TriGen Reconstruction Nail. D. Integrated Interlocking InterTan Nail. (A,D: Courtesy of Smith & Nephew, Inc., Memphis, TN.)

   

   

  

   

  FIG 5 • A. AP over-the-top C-arm position. B. Lateral C-arm position for true lateral of hip. C. Scissors position of legs and angulation of C-arm head for true alignment.

  D. Lateral decubitus position with

  C-arm. B D

   

  head fixation screw and have proximal shaft diameters around 16 to 18 mm.

  • New-generation trochanteric nails are moving to smaller geometries of 15.5 to 17 mm in diameter to conserve bone stock.

  • New designs in femoral head fixation are also in use, with spiral blade nail devices for femoral head fixation (TFN, Synthes) and integrated interlocking two-screw fixation (InterTan, Smith & Nephew) with the design goal of improving fracture stability.

    Positioning

  • Intramedullary techniques for the proximal femur are best managed with a modern fracture table with image intensification (C-arm) capabilities.

  • Although the lateral decubitus approach may be helpful for reverse obliquity patterns, the supine position is usually preferred because of the ease of setup and radiographic visualization in a familiar frame of reference.

  • We prefer bilateral foot traction with knees in extension with the legs scissored, although attachment to the fracture table via skeletal traction through the distal femur or proximal tibia is used if there are other injuries about the knee, leg, or foot.

    • The operative leg is raised to about 20 to 30 degrees of flexion and the nonoperative extremity is extended 20 to 30 degrees.

    • The legs are pulled in line with the body to avoid varus positioning of the hip.

    • The C-arm is brought in from the opposite side with the base parallel to the operative extremity, centered on the mid-femur such that the cephalad–caudad movement of the Carm gives good visualization of the femoral head and shaft in AP and lateral views.

  • With this type of setup, the true AP of the hip is usually obtained with 10 to 20 degrees of rotation of the C-arm over the top and the true lateral corresponds to about 15 to 30 degrees over the horizontal position (FIG 5A–C). The lateral

decubitus position will also require adjustment of the C-arm to correct parallax error (FIG 5D).

Approach

• The surgical approach for the entry is common for all ante-grade proximal femoral nailing.

• The incision is usually 3 to 4 cm long and is about 2 cm proximal to the greater trochanter, centered over the extrapolated middle third of the trochanter.

  • In obese or muscular individuals, this can be referenced by a line drawn transversely from the anterior inferior iliac spine and the lateral position of the incision determined by the C-arm true lateral with a radiographic marker on the skin (FIG 6).

• This approach should not damage the gluteus medius muscle, so aggressive traction or manipulation through the muscle should be avoided. The surgeon should always instrument and ream the femur with soft tissue protection in mind.

   

   

   

   

  FIG 6 • Skin incision position referencing the anterior inferior iliac spine.

   

  TECHNIQUES

   

  FRACTURE REDUCTION

  • Reduction of the fracture is tantamount to success. My preferred technique for the proximal femur involves a four-step technique.

    • After attachment to the foot positioner or skeletal traction with the perineal post attached, posterior sag is corrected at the fracture with a force directed from posterior to anterior and maintained.

    • The leg is flexed through the foot holder 20 to 30 degrees from neutral for intertrochanteric personality fractures and 30 to 40 degrees for subtrochanteric personality fractures, maintaining the posterior-to-anterior reduction force at the hip (TECH FIG 1A).

    • Traction is applied to restore length in line with the body. No varus!

    • The leg is rotated to align with the proximal fragment,

      5 to 15 degrees of external rotation for most subtrochanteric personality fractures and 10 to 15 of internal rotation for intertrochanteric personality fractures.

  • Acceptable alignment is confirmed with the C-arm in both views. The surgeon ensures there is adequate room in the pelvic and abdominal areas for the insertion of the

wires, reamers, and implants in relation to the fracture table. A 3-liter bag of saline may elevate the pelvis high enough to allow room for the instrumentation.

• The reduction can then be fine-tuned with intramedullary instruments or by percutaneous joysticks or pushers (TECH FIG 1B,C).

• If the reduction is not acceptable at this point, the surgeon should stop and re-evaluate the position of the C-arm and the amount of traction (too little or too much). The surgeon should not start reaming the proximal femur until reduction control is demonstrated.

• If reduction cannot be obtained by joysticks and percutaneous bone hooks (TECH FIG 1D), the surgeon should proceed to open reduction using the lower portion of a Watson-Jones–type approach to the hip (TECH FIG 1E–I).

• The surgeon should avoid dissecting the medial soft tissue envelope, where the vascularity is located. A single cerclage wire will be most helpful if there is a coronal split of the proximal fragment. Use of multiple cables or wires is avoided. The clamps and reduction tools are maintained as the implant is inserted.

  

  TECH FIG 1 • A. Reduction maneuver with force directed posterior to anterior at the fracture to align anterior cortices, flexion of distal fragment to match proximal fragment, and then longitudinal traction. B. Percutaneous Schanz pin as joystick in proximal fragment. C. Percutaneous joystick eccentrically placed to allow passage of reducer. D. Percutaneous joystick and percutaneous bone hook. E. Open reduction Watson-Jones with two clamps for irreducible high-energy hip fracture. F. Open reduction AP radiograph. G. Open reduction lateral radiograph. H,I. AP and lateral radiographs showing final result.

   

   

  TECHNIQUES

   

  PRECISION PORTAL PLACEMENT AND TRAJECTORY CONTROL

  • The rationale for the minimally invasive cephalomedullary surgical technique is based on three concepts to maximize bone and soft tissue conservation during nail implantation and to minimize the potential for malalignment16:

    • Precision portal placement

    • Trajectory control

    • Portal preservation

  • A precise starting point is the first criterion in ensuring an accurate reduction of proximal fractures, whether the entry portal is a modified trochanteric entry portal or a piriformis portal as defined by the selected nail geometry (TECH FIG 2A,B).

  • The proximal femur is filled with a solid cancellous bone architecture from the femoral head region until the level

    just below the lesser trochanter, where the medullary canal begins.

• Trajectory control is the development of a precise path for the nail through this solid cancellous bone, which will restore the proximal alignment in the anteroposterior and mediolateral planes.

  • This correct trajectory parallels the anterior lateral cortex of the proximal femur and allows nail juxtaposition against a solid cortical structure (TECH FIG 2C).

  • An incorrect trajectory will induce malalignment with nail insertion and result in an unstable juxtaposition against cancellous bone only, forcing the nail to migrate to the posterior cortex and resulting in a flexion deformity of the proximal fragment (TECH FIG 2D,E).

    

    TECH FIG 2 • A. Radiographic position of entry portal. Medial pin is medial trochanteric portal and lateral pin is lateral trochanteric portal. B. Lateral radiographic projection of piriformis portal; trochanteric portals will be aligned to bisect the femoral head more anteriorly. C. Anterolateral trajectory for nail in proximal femur. D,E. Incorrect nail trajectory in proximal fragment. D. Erosion of entry portal versus controlled reamed entry portal. E. Flexion deformity from posteriorly directed proximal fragment trajectory.

     

    PORTAL ACQUISITION AND PROTECTION

  • Once the correct trajectory is established, the portal and the lateral wall of the trochanter must be protected from erosion and fragmentation by the subsequent instruments for fracture reduction and canal preparation.

    • Typically, with the patient in a supine position, this erosion takes place in a posterolateral direction during reaming of the proximal femoral component, further contributing to a flexed and varus position of the proximal fragment when nail insertion occurs.

• A stepwise approach to canal preparation will simplify the nail insertion technique ( TECH FIG 3A–C).

• There are three currently published options for portal placement14:

  • Lateral trochanteric for nails with a proximal lateral angulation of more than 5 degrees

  • Medial trochanteric portal for nails with a proximal lateral angulation of 4 to 5 degrees

  • Piriformis portal for straight proximal segment nails

     

     

     

    TECHNIQUES

     

    • The guidewire drill system is inserted with soft tissue protection to the region of the greater trochanter. A 3.2-cm guidewire is inserted about 5 to 10 mm into bone in the lateral aspect of the greater trochanter.

      • This is a pivot pin about which a honeycomb type of targeter can be adjusted to precisely place the definitive guidewire pin at the tip of the greater trochanter.

    • The definitive guidewire should be just lateral to the tip of the greater trochanter for the lateral trochanteric portal, medial to the tip of the greater trochanter for the medial trochanteric portal (see Tech Fig 2A), and medial to the trochanter on the nadir of the superior femoral neck for the piriformis portal on the AP C-arm view, and all portals should be centered in the femoral neck on the lateral C-arm view.

      • The definitive guidewire should be inserted 10 to 15 mm into the trochanter and does not have to be in correct canal alignment as the definitive trajectory will be obtained in the next step.

      • Insertion of the guidewire too deeply will constrain the reamer usually into a varus fracture reduction position. This is because the flexibility of the wire and the lateral approach vector of the hip will always place the wire in a varus position when nailing in a supine position. One of the real advantages of the lateral position is allowing a more direct vector approach for the guidewire.

• A cannulated rigid reamer, preferably with modular end-cutting capability (TriGen), approximating the proximal nail geometry diameter, is introduced over the guidewire through the protective sleeve (TECH FIG 3D).

  • The rigid reamer or channel reamer is directed toward a point projected in the center of the medullary canal just distal to the region of the lesser trochanter (TECH FIG 3E).

  • The reamer is advanced in stepwise fashion while confirming maintenance of trajectory.

• After the reamer has been inserted about 20 mm, its trajectory is confirmed with a lateral C-arm view.

  • The reamer should be directed along the anterior cortex of the proximal femur. The insertion of the reamer can be adjusted during reaming to approximate the position described and is most helpful in avoiding a varus position of the proximal femur.

• Once the canal is reamed in such a fashion, the distal femur is adjusted with the fracture table to allow correct neck–shaft angulation.

• The reamer is inserted until it reaches the medullary canal just below the region of the lesser trochanter (TECH FIG 3F).

• The inner reamer is removed and the outer reamer is maintained for protection of the proximal reamer during the next step.

   

   

   

   

   

  A B C

   

   

   

   

   

   

   

  D E F

  TECH FIG 3 • A. Entry portal tool with honeycomb design targeter for pin placement (TriGen, Smith & Nephew, Inc., Memphis, TN). B. Insertion of entry portal tool through incision. C. Two-pin technique through honeycomb targeter to precisely acquire entry site of pin. D. Channel reamer insertion through entry portal tool for soft tissue protection. E. AP radiograph of trajectory for medial trochanteric portal. F. Lateral radiograph of correct anterolateral portal with channel reamer. (A: Courtesy of Smith & Nephew, Inc.)

   

   

   

  TECHNIQUES

   

  FRACTURE REDUCTION AND CANAL PREPARATION

  • A fracture reducer (TriGen) or similar curved cannulated device is inserted through the retained channel reamer to the fracture site and threaded through the fracture site into the distal fragment intramedullary canal, with manipulation in appropriate planes to align the fracture (TECH FIG 4A).

  • A long guide rod is inserted to the knee if a long nail is desired, confirming that the wire does not impinge on the anterior cortex distally.

    • Preferably the guide rod should be inserted to the old physeal scar and centered on AP and lateral C-arm views (TECH FIG 4B).

  • The reducer is removed and the guidewire position is maintained with an obturator proximally.

  • Length is checked with an appropriate ruler, allowing for fracture distraction and nail final position.

  • The diaphyseal region is reamed up to 1 mm over the desired nail size (up to 2 mm for excessive anterior bows) (TECH FIG 4C).

    • The proximal expansion of the nail should have already been reamed with the entry portal reamer, but the surgeon should always confirm diameters.

  • The channel reamer is removed and the selected nail is inserted (TECH FIG 4D).

  • For long trochanteric nails, it is helpful to rotate the nail 90 degrees anteriorly during the first half of the nail insertion to minimize hoop stresses in the proximal femur. After partial insertion, the nail is rotated to the anticipated anteversion required for femoral head fixation.

  • The last 5 cm of the nail is inserted after releasing distraction sufficient for fracture apposition, maintaining correct rotational alignment.

  • Most commercial guides use reference marks to align with the femoral head on the lateral C-arm view. These same guides may be used for C-arm verification of correct depth of insertion to allow optimal femoral head fixation.

  • The long guide rod is removed to proceed with interlocking.

• Proximal interlocking will depend on the type of implant selected, but most designs recommend that the screw be placed as close to center-center position as possible.

  • If a secondary screw is included in the nail design constructs (ie, Reconstruction or InterTan), there is usually sufficient room for the second screw inferiorly, but care should be exercised in small patients.

     

     

     

     

     

     

    A B

     

     

     

     

     

    C D

    TECH FIG 4 • A. Insertion of reducer through channel reamer, lateral radiographic view.

    B. Reducer directed guide rod centered on lateral radiograph, avoiding anterior distal cortex. C. Diaphyseal reaming through channel reamer. D. Nail insertion. For trochanteric nail, the surgeon matches the curve of the nail with the proximal femur during initial insertion to minimize hoop stress at entry portal. The nail is rotated into correct position after 30% to 50% insertion.

     

     

    TECHNIQUES

     

    SINGLE-SCREW OR SINGLE-DEVICE DESIGNS (GAMMA, IMHS, TFN [SYNTHES, PAOLI, PA])

     

    • The center-center wire is inserted to within 5 mm of subchondral bone. Fracture reduction is confirmed and the length to lateral cortex is measured.

    • If compression is desired (usually 5 mm), the surgeon reams for the screw and selects a screw 5 mm shorter than measured. For the TFN, the head is not reamed.

       

• The surgeon inserts the head fixation screw or nail to the desired depth; position is confirmed on AP and lateral Carm views (TECH FIG 5A).

• The option of compression and locking of the lag screw with a set-screw within the nail is available on selected systems (TECH FIG 5B,C).

   

   

   

   

   

   

   

  C

   

  TECH FIG 5 • A. Gamma nail AP view with lateral trochanteric portal and center-center head screw position. B. Russell-Taylor IIB fracture

  A B with short InterTan nail AP. C. Lateral view.

   

  TWO-SCREW RECONSTRUCTION (TRIGEN)

  • Using the proximal targeting guide attached to the nail, the surgeon inserts the most distal proximal guidewire along the femoral calcar within 5 mm of the inferior femoral neck, centered on the lateral C-arm view, to within 5 mm of subchondral bone (TECH FIG 6A).

  • Through the proximal targeting guide attached to the nail, the surgeon inserts the most proximal guide pin, which will be close to the center position of the femoral head parallel to the first guide pin. Its position is confirmed with the C-arm.

• The surgeon removes the inferior guidewire, drills and reams for the selected lag screw for the system, and inserts the inferior screw (TECH FIG 6B).

• The same steps are repeated for the proximal screw, and final fixation is confirmed on AP and lateral radiographs (TECH FIG 6C).

• Traction is released before final tightening of the lag screws to allow fracture compression.

   

   

   

   

   

   

   

  A B C

   

  TECH FIG 6 • A. Trochanteric reconstruction nail with inferior drill placed first along medial neck. B. Inferior lag screw placed first. C. Lateral radiographic view of head screw position.

   

   

  TECHNIQUES

   

  INTEGRATED SCREW CEPHALOMEDULLARY NAIL (INTERTAN)

  • Whereas the previous techniques for femoral head fixation used devices that gain compression by impaction or compression against the lateral cortex, this device uses a gear drive mechanism that compresses the nail against the endosteal surface of the medial cortex and simultaneously compresses the proximal femoral head and neck to the medial surface of the nail (see Tech Fig 5B,C).

    • This design conceptually improves rotational and trans-lational stability to the proximal femoral construct.

  • The 3.2-mm guidewire is inserted through the proximal targeting guide and advanced in a center position of the femoral head to within 5 mm of subchondral bone, after confirming correct depth and anteversion (TECH FIG 7A–C).

  • The inferior lateral cortex is drilled through the targeting guide with a step drill to clear away bone from the nail attachment site for the gear drive. The inferior screw hole is then drilled to within 5 mm of the center-center guidewire tip (TECH FIG 7D).

• The derotation bar is inserted into the inferior hole to augment femoral head and neck stability during large lag screw reaming (TECH FIG 7E,F).

• The surgeon confirms the length for the lag screw, subtracting 5 to 10 mm from the measured length for compression if desired.

  • The 3.2 wire is overdrilled with the 10.5-mm cannulated drill, and the selected lag screw is inserted to within 5 mm of subchondral bone (TECH FIG 7G).

• The derotation bar is removed and the compression gear drive screw is inserted through the guide. Traction is released from the leg and compression is started (TECH FIG 7H–K).

  • Compression though the gear drive does not begin until the head of the gear drive screw contacts the nail.

  • Visualization of compression can be confirmed by Carm and calibrations on the guide.

• Once compression is achieved, the screwdrivers are disassembled. Static locking of the screw assembly can be achieved with the integrated set screw within the nail.

A B C

D

TECH FIG 7 • Integrated screw cephalomedullary nail (InterTan, Smith Nephew, Inc.). A. Pilot drill hole for 3.2-mm wire for center-center position. B. AP radiograph with radiolucent alignment tower. C. Lateral radiograph with radiolucent guide centered over femoral head. D. Inferior screw hole for derotation bar and compression screw. E,F. Derotation bar inserted. G. Drill for cannulated cen-

G ter lag screw. (continued)

TECHNIQUES

TECH FIG 7 • (continued) H–J. Insertion of inferior compression screw and final AP and lateral views of integrated screws engaged. K. Schematic of integrated screws and nail in fracture. (K: Courtesy of Smith & Nephew, Inc., Memphis, TN.) K

DISTAL INTERLOCKING TECHNIQUE

• Short nails have distal locking capability, usually in a static or dynamic mode with most modern designs. I prefer dynamic locking.

  • Most systems have this hole targeted through the proximal nail guide, and a single bicortical screw is usually sufficient.

• Long nails have distal locking capability with either static holes or a combination of static and dynamic.

  • For length-stable proximal fractures, one bicortical screw is sufficient in a dynamic mode.

  • Conversely, for segmental fractures or extensive comminution, two screws may be preferred.

  • Distal interlocking is most commonly done using the same freehand technique used in the conventional femoral interlocking nail technique (TECH FIG 8).

    TECH FIG 8 • Distal freehand technique for long nails.

     

    WOUND CLOSURE FOR ALL NAILS

• With attention to detail, minimal damage to the muscle and skin is incurred with nail techniques, so wound irrigation and standard layered closure are performed.

   

   

   

  PEARLS AND PITFALLS

   

   

  Reduction in the ■ The height of the perineal post is adjusted to effect medial displacement of the shaft. This is lateral position especially helpful with reverse obliquity pertrochanteric patterns (Russell-Taylor IIA).

  Reduction in the ■ The surgeon should avoid placing the hip in varus to gain entry into the bone. This leads to a varus supine position trajectory in the proximal bone stock, which will recur with nail insertion.

  • The key to reduction is the rotation of the distal fragment to the externally rotated proximal fragment and apposition of the anterior cortex of the proximal and distal fragments. These two points will allow correction of the flexion and malrotation deformities.

  • After nail insertion, the rotational alignment of the proximal femur may change, so before distal interlocking, the surgeon should check length on the lateral C-arm view and match of cortex anteriorly and posteriorly for equivalent thickness. I use a C-arm–verified true lateral view of the hip, mark the rotation of the C-arm on its axis, and then move the C-arm to the distal femur and visualize a true lateral of the knee with overlap of the femoral condyles and mark the rotation of the C-arm. Simple subtraction of these two values gives me the approximate anteversion. For most patients, 15 degrees is the average, although some Asian patients have up to 30 degrees. Then, by rotating the distal fragment, alignment is set and the nail is finally fully seated.

    Entry portal ■ The medial trochanteric portal greatly simplifies the access to the proximal femur, and the use of

    a rigid reamer system minimizes false trajectories and trochanteric iatrogenic fractures. The surgeon should avoid letting the reamer lateralize in the greater trochanter at any time.

  • The medial trochanteric portal uses less radiation and operative time and is preferred in the supine position.15

    Trajectory control ■ The concept of trajectory control places the nail in apposition to the anterolateral cortex, minimizing flexion deformities at the fracture site, and conserves bone stock proximally by avoiding cutout of the reamer posteriorly.

    Nail insertion ■ Rotation of the trochanteric design nails during the first half of insertion minimizes stress on the greater trochanter and medial cortex of the femur below the lesser trochanteric region in long nail designs.

  • The surgeon should remember to let off traction before final seating of the nail to avoid nailing the femur in distraction.

  • Nails must have stability by cortical contact in the proximal and distal femur. Disruption of the lateral wall places more stress on the construct and should be reconstructed separately from the nail if displaced, or a locking proximal plate may be required. Special care is required for

    Russell-Taylor IIA and B fracture patterns.

    Proximal screw ■ Guidewire insertion and drilling should always be performed with a high speed rate and a slow feed targeting rate. This means that the guidewires and reamers bend and can be misdirected with excessive axial

    force during drilling.

  • For single-device and integrated screw femoral head fixation, the surgeon should use a center-center position for the large lag screw.

  • For two-device femoral head fixation (reconstruction), the inferior screw is placed first along the medial calcar of the femoral neck; this will ensure room for the proximal screw.

Distal locking ■ Distal locking is usually recommended with a dynamic single screw for short and long nails. Two distal interlocking screws are recommended for comminuted or segmental fractures.

POSTOPERATIVE CARE

• AP and lateral radiographs of the final construct should be obtained in the surgical suite before recovering the patient to assess the construct and ensure stability.

  • If there are adjustments to be made, these are best made while the patient is still under anesthesia.

  • Radiographs should reveal the entire fracture region, including the entire implant construct.

• Patients are mobilized to a chair upright position the day after the operative procedure.

• Ambulation with supervision is allowed, with weight bearing as tolerated with a walker or crutches and emphasis on heel-strike and upright balance exercises.6

  • Multiple trauma or patients with other complications may have delayed ambulation, but it should begin as soon as possible to minimize secondary complications.

• Patients are re-evaluated with an examination and ra-

diographs at 2 weeks and then monthly thereafter until fracture healing is documented and the patients have maximized ambulatory capabilities, usually by 6 months after the injury.

• The surgeon should emphasize good nutrition and hip ab-ductor exercises bilaterally.

• Patients must be counseled to report any increased swelling or respiratory distress as an emergency because of the high risk of thromboembolic disease.

   

  OUTCOMES

• Union of these fractures is high (more than 95%).

• Functional recovery is poor in many patients, however, with more than 60% of patients failing to recover their preinjury level of function.8

• Mortality within the first year in patients older than 55 is 20% to 30%.

FIG 7 • Nail failures. A. Proximal screw cutout.

A B B. Distraction nonunion with spiral blade nail construct.

• Many patients sustain progressive collapse of the hip into varus and shortening of the leg with the current generation of sliding hip screw fixation.9

  COMPLICATIONS

• Loss of construct stability is one of the most common complications. It is manifested by collapse of the screw and varus migration of the femoral head construct, with final cutout failure in the worst cases.

  • This occurs to a small degree in all cases, as the sliding impaction was designed to minimize catastrophic cutout.

  • A center-center position of single-screw devices minimizes cutout.3

• Nail cutout is a much more serious complication, involving loss of fixation of the nail component in the proximal femur or periprosthetic femoral fracture with short nails; this will result in reoperation with locking construct plates or 95-degree blade plates, exchange for longer nails, or even prosthetic replacement in severe cases (FIG 7A).

• Nonunion, though rare (1% in older patients), is usually treated with total hip replacement and grafting and implant revision in young patients (FIG 7B).

• Infection occurs in 1% to 2% of postoperative cases and is minimized by preoperative antibiotics, usually a cephalosporin class of antibiotic.

  • In immunocompromised and malnourished patients, standard care involves isolation and sensitivity testing of the causative bacteria and appropriate intravenous antibiotics, in consultation with an infectious disease specialist, and standard débridement and irrigation for wound care.

  • If the implant is stable, it should be retained. Rarely will a resection arthroplasty be required.

REFERENCES

1. Alam A, Willett K, Ostlere S. The MRI diagnosis and management of incomplete intertrochanteric fractures of the femur. J Bone Joint Surg Br 2005;87B:1253–1255.

2. American Academy of Orthopaedic Surgery website (AAOS.org), Hip Fractures, 2007.

    

3. Baumgaertner MR, et al. The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone Joint Surg Am 1995;77A:1058–1064.

4. Gotfired Y. The lateral trochanteric wall: a key element in the reconstruction of unstable pertrochanteric hip fractures. Clin Orthop Relat Res 2004;425:82–86.

5. Jin WJ, Dai LY, Cui YM, et al. Reliability of classification systems for intertrochanteric fractures of the proximal femur in experienced orthopaedic surgeons. Injury 2005;36:858–861.

6. Koval KJ, et al. Postoperative weight-bearing after a fracture of the femoral neck or an intertrochanteric fracture. J Bone Joint Surg Am 1998;80A:352–356.

7. Lippmann RK. The use of auscultatory percussion for the examination of fractures. J Bone Joint Surg 1932;14:118.

8. Miller CW. Survival and ambulation following hip fracture. J Bone Joint Surg Am 1978;60A:930.

9. Moroni A, Faldini C, Pegreffi F, et al. Dynamic hip screw compared with external fixation for treatment of osteoporotic pertrochanteric fractures: a prospective randomized study. J Bone Joint Surg Am 2005;87A:753–759.

10. Ostrum RF, Levy MS. Penetration of the distal femoral anterior cortex during intramedullary nailing for subtrochanteric fractures: a report of three cases. J Orthop Trauma 2005;19:656–660.

11. Ostrum RF, Marcantonio A, Marburger R. A critical analysis of the eccentric starting point for trochanteric intramedullary femoral nailing. J Orthop Trauma 2005;19:681–686.

12. Palm H, Jacobsen S, Sonne-Holm S, et al. Integrity of the lateral femoral wall in intertrochanteric hip fractures: an important predictor of a reoperation. J Bone Joint Surg Am 2007;89A: 470–475.

13. Pepper J, Russell TA, Sanders R, et al. Minimally invasive intramedullary nail insertion instruments and method. U.S. Patent 5951561, 9/14/1999.

14. Perez EA, Jahangir AA, Mashru RP, et al. Is there a gluteus medius tendon injury during reaming through a modified medial trochanteric portal? J Orthop Traumat 2007;21:617–620.

15. Ricci WM, Schwappach J, Tucker M, et al. Trochanteric versus piriformis entry portal for the treatment of femoral shaft fracture. J Orthop Trauma 2006;20:663–667.

16. Russell TA, Mir HR, Stoneback BS, et al. Avoidance of malreduction in proximal femur fractures: minimally invasive nail insertion technique. J Orthop Trauma 2008;22:391–398.

17. Russell TA, Taylor JC. Subtrochanteric fractures. In: Browner B, ed. Skeletal Trauma. Philadelphia: WB Saunders, 1993.