SURGICAL TIPS AND TRICKS IN FRACTURES OF FEMUR

DR. Praveen Mehar. J

DNB ORTHO

FRACTURE NECK OF FEMUR

ANATOMY :• Cross section anatomy of femoral head in adult shows that the trabecularpattern becomes becomes more and more concentrated towards centre with age.• This is the reason for central placement of screws or implants in fractures of femur neck.

• Normally the tip of the greater trochanter is at or just above the center of rotation of head.

• The distance from the center of the femoral head to the tip of the greater trochanter is normally two to two and a half times the radius of the femoral head.

• When the proximal femur is viewed from above, it can be seen that the greater trochanter is not centered on the neck but flares posteriorly some 30°–40°.

• So, the more proximal the point of entry of a fixation device, the more anterior it must be in order to come into line with the axis of the neck.

• A 90° or 95° device must be inserted in the anterior half of the trochanter, and any device which is inserted through the shaft into the neck and head must be inserted into the middle of the lateral surface of the femur.

• Any posterior placement along the lateral surface of the shaft results in the device entering the anterior half of the head, and any anterior insertion results in the device entering the posterior half of the head.

• Such errors of insertion cannot be corrected by changing the angle of insertion of the device.• The angle of insertion of a screw or of an angled device that is to traverse the neck and enter the head is also given by the anteversion of the neck. Such devices must be inserted parallel to the plane of anteversion.

• The specific configuration of the arterial blood supply of the head is responsible for its interruption in fractures of the neck.

• The posterior superior and the posterior inferior retinacular vessels arise from medial circumflex femoral artery. They give epiphyseal arteries through sub synovial ring to supply head. Lateral femoral circumflex femoral artery gives branches anteriorly and supply neck.

• So, very very important…..Posterior vessels --------> supply only head( mainly posterosuperior) and

some neckAnterior vessels ------- --- > supply only neck.

• This configuration of the vessels must be kept in mind whenever surgically approaching the neck and head of the femur, and the surgeon must be very careful not to place retractors around the posterior aspect of the neck, as this could seriously interfere with the blood supply of the head.

FRACTURE NECK OF FEMUR

• CLASSIFICATIONS :

1. Pauwel based on fracture angle

2. Garden based on trabeclar pattern

3. Anatomic –a. subcapital

b. transcervical

c. basicervical

METHODS OF REDUCTION OF FRACTURE

• CLOSED

• OPEN

• CLOSED REDUCTION MANEUVRES :

A : IN HIP FLEXION : 1. LEADBETTER

2. SMITH PETERSON

3. FLYNN

B : IN HIP EXTENSION : 1: WHITMAN

2: Mc EVELENNY

3: DEYERLE

1. WHITMAN’S METHOD : TRACTION INTERNAL ROTATION ABDUCTION

2. LEADBETTER’S METHOD : TRACTION HIP FLEXION 90 DEGREES 45DEGREE INTERNAL ROTATION FULL FLEXION + ADDUCTIONABDUCTION+EXTERNAL ROTATION

MOST SUCCESSFUL.

REDUCTION TESTED BY HEEL PALM TEST

3. FLYNN METHOD : MOST ATRAUMATIC.BASED ON SPIRAL CONFIGURATION OF CAPSULE FIBRES.

HIP FLEXION AND SLIGHT ABDUCTION LATERAL TRACTIONOF NECK INTERNAL ROTATION EXTENSION.

IN GENERAL : The mechanism of displacement is simple.

• The femoral head displaces into varus and retroversion as the leg shortens and the femoral shaft externally rotates.

• The gentlest manipulation under anesthesia with full relaxation, which often brings about a reduction, consists of applying longitudinal traction and then gentle internal rotation.

• This is usually done with an image intensifier in place, which allows for an immediate check of the reduction obtained.

• The traction brings the head out of varus and the internal rotation corrects the retroversion.

• If this maneuver fails, it can be repeated, but it must be remembered that any further manipulation increases the risk of rendering the head avascular

FLYNN’S MANEUVRE :

WHAT IS ADEQUATE REDUCTION ???

• Aim is for an anatomical reduction or one with the head in slight valgusand with the head in neutral version or minimally anteverted.

• Any degree of residual varus or retroversion is unacceptable, because it leads to an unacceptable incidence of failure as a result of loss of fixation and redisplacement.

• Therefore, proper reduction is one of the most essential factors for the successful treatment of neck fractures.

METHODS OF FIXATION

• CANNULATED SCREW FIXATION

• DYNAMIC HIP SCREW

• HEMIARTHROPLASTY

• TOTAL HIP ARTHROPLASTY

CANNULATED SCREW FIXATION PEARLS :

•The screws should be inserted parallel to the axis of the neck and parallel to each other.

•They must be parallel to each other not only to act together as lag screws, but more importantly, if there is any resorption at the fracture, they must not block the head from settling down on the neck.

• If the screws are not parallel they can block the shortening, and instead of backing out they can advance through the head and perforate into the joint.

The cancellous screws used for fixation of a subcapital fracture must be parallel to one another. If the neck should resorb, the screws must be able to back out. If the screws were not parallel they could penetrate through the head instead

TIPS : • Check for spurt of blood coming from lateral cortex just one finger breadth above the insertion of gluteus maximus.This is the entry for inferior screw insertion.

• Screw should be placed at 45 degrees to shaft or parallel to neck or in the direction of opposire ASIS under c arm visualisation.

• Direction of neck can be checked by putting guidewire directly in the anterior aspect of neck.

• Palpate for ridge of vastus lateralis and put second wire parallel to first wire. This passes along the superior border of neck.

• Third wire can be inserted either centre or slight anterosuperior.

DECISION MAKING

• Undisplaced Fractures : CC Screw fixation

• Displaced Fractures : ORIF with CC Screws,DHS,

Hemiarthroplasty

• Age : less than 65 years : preserve head with ORIF

More than 65 years : Hemiarthroplasty.

INTERTROCHANTERIC FRACTURES

• Intertrochanteric fractures, more correctly referred to as pertrochantericfractures, are fractures that occur in the region joining the greater and lesser trochanters.

• This is the insertion site of large muscle masses and is therefore a region with a very abundant blood supply.

• Nonunion of these fractures is rare, and if completely neglected these fractures usually heal with varus shortening and external rotation.

• The displacement of fracture fragments depends on the musculotendinousattachments of the respective fragments.

• The greater trochanter is abducted and externally rotated by gluteus mediusand short external rotators.

• The shaft is displaced posteriorly and medially by adductors and hamstrings. This results in shortening and varus deformities.

• Dorr classified the morphological anatomy of proximal femur as Type A Narrow canal, narrow isthmus, thick cortexType BWide canal, wide isthmus but good cortexType CWide canal,wide isthmus, weak cortex.

• The choice of implant has been selected based on the morphological pattern of proximal femur.

CLASSIFICATION

• While several classification systems exist for these fractures, they are all based on the concept of stability.

• A stable fracture is a simple one that, once reduced and fixed, is compressed and minimally impacted by the nearly perpendicular weight-bearing force of single leg stance.

• Unstable fractures due either to comminution, ‘reverse oblique’ orientation, or both, are associated with collapse on axial loading.

• Both the posteromedial cortex and the lateral cortical buttress beneath the vastus ridge contribute to the stability of these fractures. The instability increases with the degree of comminution of the posteromedialcortex. Increased comminution implies less support for axial loading through cortical contact.

• The lateral cortex beneath the vastus ridge provides the final buttress to impaction of the fracture after fixation, further contributing to its stability and avoiding collapse. Incompetence of either of these cortical regions therefore renders a fracture unstable.

REDUCTION OF FRACTURE

CLOSED REDUCTION :

• The reduction of these fractures is carried out on the fracture table with

the aid of image intensification.

• The limb is placed in traction and in slight abduction and internal rotation. This is usually sufficient to align the femoral head and neck fragment with the shaft and recreate the patient’s normal neck shaft angle.

• It is important to check on the lateral projection that the shaft has not sagged posteriorly. If this happens, it must be corrected. Frequently, this deformity cannot be corrected by simply externally rotating the limb, although this maneuver will help to realign the fragments.

• Because the shaft has sagged, it must be lifted upwards and held there to secure reduction.

Implant options for the treatment Of intertrochantericfractures of the hip

RATIONALE, EVIDENCE, AND RECOMMENDATIONSA. R. Socci,N. E. Casemyr,M. P. Leslie,M. R. Baumgaertner, From Yale University School of

Medicine,Connecticut, United States

• Stable intertrochanteric fractures : There is currently little evidence of the superiority of one device over another in the management of these fractures. The quality of reduction remains paramount, with stable fractures having direct cortical contact following accurate reduction. There is a preference for SHS fixation after careful reduction.

• Subtrochanteric and reverse oblique fractures : There is strong evidence to support the use of intramedullary fixation in subtrochanteric and reverse oblique fractures. The biomechanics of these fractures are such that fixation with a SHS is inappropriate, as the line of collapse is not perpendicular to the fracture line and the lateral cortical buttress cannot resist collapse.

Importance of screw position in intertrochanteric femoral fractures treated by dynamic hip screw

M. Guvena,∗, U. Yavuzb, B. Kadıo˘glu c, B. Akmand,V. Kılınc，o˘glu e, K. Unayc, F. Altıntas

Measurement of the distance between the tip of the lag screw to the apex of the femoral head (X) and the diameter ofthe lag screw (D) on the (a) anteroposterior and (b) lateral radiographs. (Tip-apex index = X anteroposterior x [True diameter / Danteroposterior] + X lateral x [True diameter / D lateral]).

Determination of the screw position in the femoral head according to the Parker’s ratio method on the (a) anteroposterior and (b) lateral radiographs (Parker’s ratio = ab / ac).

• Cut-out of the lag screw has been shown to be the most common cause of failure and is related to the position of the screw in the femoral head .

• There have been two published methods in the literature, which quantify thescrew position, including tip-apex distance (TAD) and the Parker’s ratio method.

•TAD is the sum of the distance from the tip of the lag screw to the apex of the femoral head on anteroposterior and lateral radiographs after controllingfor magnification. Baumgaertner and Solberg concluded that the distance greater than 25mm was a strong predictor of cut-out.

• Parker described a ratio method and reported that cut-out was more frequent when the screw was placed superiorly and posteriorly on the anteroposteriorand lateral radiographs.

• Femoral head was divided into thirds on the anteroposterior and lateral radiographs . The ratio of the screw position gave a range of zero to 100 and a ratio greater than 66 was accepted as a superior and posterior position of the lag screw on the anteroposterior and lateral radiographs.

• On the contrary, Kaufer advised to place the implant more posteriorly and inferiorly . He concluded that this position placed the tip of the implant into the bone formed by decussation of tension and compression trabeculae, thus assuring maximum proximal fragment control.

• Peripheral placement of the lag screw in the femoral head inherently increases TAD.

•However, the placement of the screw in posterior and inferior locations of the femoral head supports the comminuted posteromedial cortex and the device allows impaction of the fracture surfaces, shortening the lever arm, decreasing the bending moment, as well as avoiding cut-out of the screw from the femoral head, consequently.

•The DHS construct allows mechanical load transmission. In stable fracture patterns, it acts as a tension band producing more force transmission through the medial cortex, stressing the implant more in tension and less in bending.

• But, in unstable fractures, the lesser trochanter and the part of the calcar femoral are missing from the mechanical load transmission system because of the lack of bony support over the medial aspect of the femur.

Intertrochanteric Fractures:Ten Tips to Improve Results

1. Use the tip to apex distance

2. No lateral wall, no hip screw

3. Know the unstable intertrochanteric fracture patterns and nail them

4. Beware of anterior bow of femur during nailing( ideal radius is 1.5-2.2m)

5. When using PFN, start slight medial to exact tip of GT.

6. Be cautious about nail insertion trajectory, and do not use a hammer

to seat the nail.

7. Avoid varus angulation of the proximal fragment. Use the relationship

between the tip of the trochanter and the center of femoral head.

8. Do not ream an unreduced fracture.

9. When nailing, lock the nail distally if the fracture is axially or

rotationally unstable.

10. Avoid fracture ditraction during nailing.

Straight nail inserted into a bowed femur. Vigorous impaction or a bow mismatch may lead to perforation of the distal anterior femoral cortex

The ideal starting point is slightly medial to the exact tip of the greater trochanter. Note the good position of the guidewire distally

A fracture locked in distraction. Note the typical lateral starting point and the high hip-screw placement.

SUBTROCHANTERIC FEMUR FRACTURES: TIPS AND TRICKS, DO’S AND DON’TS

Characteristic appearance of a subtrochanteric femur fracture with (A) varus and external rotation deformity of the proximal fragment because of the pull of theabductors and external rotators; the distal fragment is pulled mediallybecause of the adductors, and (B) flexion is caused by the pull of the iliopsoas.

• Implant selection for definitive fixation ends up as a choice between using a blade-plate, locking-plate, or an IMN construct.

• Overall, one should avoid the use of screw- and side-plate constructs, because outcomes and high rates of cutout have caused it to fall out of favor.

• Biomechanically, IMN fixation is superior for several reasons.

• First, its increased rigidity, stiffness, and shorter moment arm allows for a biomechanically stronger construct with decreased strain placed on the implant.

• Spanning the entire length of the femur, IMN allows for a more efficient and shared load transfer and resists greatly, the deforming forces that occur, primarily, by preventing excessive medialization of the femoral shaft caused by the pull of the adductors.

• Superior stiffness is inherent in IMN, because of its closed-section design, which yields bending stiffness similar to that of an intact femur.

• These biomechanical advantages translate into the clinical realm, with primary benefits, including less softtissue dissection, potentially less blood loss, restoration of the mechanical axis, and arguably, most importantly, allowance for immediate weight bearing after fixation as per surgeon’s recommendations.

Tips and Tricks in Achieving Reduction Before IMN Placement :

• Supine position >>> Lateral position ( obese patients)

• Percutaneous joysticks

• Femoral distractor

• Finger reduction Tool

• Blocking screws

• Clamp-assisted reduction

• Schanz pins

Finger reduction tool and guide wire placement

Blocking screws (arrows) placed in the concavity of the deformity may help aid in maintaining nail position and prevent cutout.

Small open incision with minimal soft dissection to clamp (C and D) and maintain reduction to facilitate ideal IMN placement.