Subtrochanteric Femoral Neck Fractures, Causes, Treatment

Subtrochanteric Femoral Neck Fractures
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Subtrochanteric Femoral Neck Fractures/Femur Neck Fractures is a flattened pyramidal process of bone, connecting the femoral head with the femoral shaft, and forming with the latter a wide angle opening medial ward. Femoral neck fractures account for nearly half of all hip fractures with the vast majority occurring in elderly patients after simple falls[]. Currently, there may be sufficient evidence to support the routine use of hip replacement surgery for low demand elderly patients in all but non-displaced and valgus impacted femoral neck fractures. This is based on a multitude of randomized controlled trials documenting improved short and long-term hip function and lower re-operation rates with hip arthroplasty as compared to internal fixation in elderly adults[]. Furthermore, early weight bearing protocols post-arthroplasty minimizes complications of prolonged inactivity[].

Intertrochanteric Femoral Neck Fractures

Types of Femur Neck Fractures

Since the disruption of blood supply to the femoral head is dependent on the type of fracture and causes significant morbidity, diagnosis and classification of these fractures are important. There are three types:

  • Subcapital – femoral head/neck junction
  • Transcervical – midportion of the femoral neck
  • Basicervical – the base of the femoral neck

or

  • subcapital is the femoral head and neck junction
  • transcervical is the mid-portion of the femoral neck
  • basicervical is the base of the femoral neck

Most significantly, subcapital and transcervical fractures are considered intracapsular while basic cervical fractures are considered extracapsular

Subtrochanteric Femoral Neck Fractures

Classification

The Winquist and Hansen classification is a system of categorizing femoral shaft fractures based upon the degree of comminution.[rx

TypeDescription
ITransverse or short oblique fractures with no comminution or a small butterfly fragment of less than 25% of the width of the bone
IIComminuted with a butterfly fragment of 50% or less of the width of the bone
IIIComminuted with a large butterfly fragment of greater than 50% of the width of the bone
IVSegmental comminution

Garden classification of femoral neck fractures.

Garden classification of femoral neck fractures.

  • Type I—incomplete
  • Type II—complete, nondisplaced
  • Type III—complete, displaced < 50%
  • Type IV—complete, displaced > 50%

or

Garden classification of femoral neck fractures.
TypesDescription
1Incomplete Stable fracture with impaction in valgus
2Complete but non displaced with two groups of trabeculae in line
3completely displaced with varus with all three trabeculae disturb.
4Completely displaced with no contact between the fracture fragments

For low-grade fractures (Garden types 1 and 2), the standard treatment is a fixation of the fracture in situ with screws or a sliding screw/plate device. In elderly patients with displaced or intracapsular fractures, many surgeons prefer to undertake a hemiarthroplasty, replacing the broken part of the bone with a metal implant. In elderly patients who are medically well and still active, a total hip replacement may be indicated.

Anatomy of Femur Neck Fractures

The hip joint, an enarthrodial joint, can be described as a ball and socket joint. The femur connects at the acetabulum of the pelvis and projects laterally before angling medially and inferiorly to form the knee. Although this joint has three degrees of freedom, it is still stable due to the interaction of ligaments and cartilage. The labrum lines the circumference of the acetabulum to provide stability and shock absorption. Articular cartilage covers the concave area of the acetabulum, providing more stability and shock absorption. Surrounding the entire joint itself is a capsule secured by the tendon of the psoas muscle and three ligaments. The iliofemoral, or Y, the ligament is located anteriorly and serves to prevent hip hyperextension. The pubofemoral ligament is located anteriorly just underneath the iliofemoral ligament and serves primarily to resist abduction, extension, and some external rotation. Finally, the ischio femoral ligament on the posterior side of the capsule resists extension, adduction, and internal rotation. When considering the biomechanics of hip fractures, it is important to examine the mechanical loads the hip experiences during low energy falls.

Femoral head vascularity is at risk after femoral neck fractures because the vascular supply is intra-capsular. The most common hypotheses of causes for femoral head ischemia after femoral neck fracture are direct disruption or distortion of the intra-capsular arteries during the initial femoral neck fracture, compression secondary to elevated intra-capsular pressure due to fracture hematoma, pre-operative traction and quality of the surgical reduction and its ability to restore blood flow[].

Blood supply to the femoral head comes from three main sources, the medial femoral circumflex artery (MFCA), the lateral femoral circumflex artery (LFCA) and the obturator artery. The majority of the blood supply to the femoral head, more specifically to the vital superior-lateral weight-bearing portion, comes from the lateral epiphyseal artery, a branch of the MFCA. This artery courses up to the posterior-superior aspect of the femoral neck where it is prone to damage during femoral neck fracture fragment displacement. The second largest contributor to femoral head blood supply is the LFCA whose ascending branch gives rise to the inferior metaphyseal artery supplying the anterior-inferior aspect of the femoral head. Finally, the smallest and most variable contributor to the blood supply in the adult femoral head is via the obturator artery which enters the head via the ligamentum teres[].

Causes of Femur Neck Fractures

Subtrochanteric Femoral Neck Fractures

  • Sudden forceful  fall down
  • Road traffic accident
  • Falls – Falling onto an outstretched hand is one of the most common causes of the broken neck of the femur.
  • Sports injuries – Many necks of femur fracture occur during contact sports or sports in which you might fall onto an outstretched hand — such as in-line skating or snowboarding.
  • Motor vehicle crashes – Motor vehicle crashes can cause necks of femur fracture to break, sometimes into many pieces, and often require surgical repair.
  • Have osteoporosis –  a disease that weakens your bones
  • Eave low muscle mass or poor muscle strength – or lack agility and have poor balance (these conditions make you more likely to fall)
  • Walk or do other activities in snow or on the ice – or do activities that require a lot of forwarding momenta, such as in-line skating and skiing
  • Wave an inadequate intake of calcium or vitamin D
  • Football or soccer, especially on artificial turf
  • Rugby
  • Horseback riding
  • Hockey
  • Skiing
  • Snowboarding
  • In-line skating
  • Jumping on a trampoline
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Symptoms of Femur Neck Fractures

Common symptoms of   fractures include:

  • Severe pain that might worsen when gripping or squeezing or moving your hip.
  • Inability to move immediately after a fall
  • Severe pain in your hip or groin.
  • Inability to put weight on your leg on the side of your injured hip
  • Stiffness, bruising and swelling in and around your hip area
  • Shorter leg on the side of your injured hip
  • Turning outward of your leg on the side of your injured
  • Swelling
  • Tenderness
  • Bruising
  • Obvious deformity, such as a bent hip.
  • Pain
  • Pain, especially when flexing the hip
  • Deformity of the wrist, causing it to look crooked and bent.
  • Your hip is in great pain.

Diagnosis of Femur Neck Fractures

Physical exam

  • Femoral shaft fractures occur during extensive trauma, and they can act as distracting injuries, whereby the observer accidentally overlooks other injuries, preventing a thorough exam of the complete body.[rx] For example, the ligaments and meniscus of the ipsilateral (same side) knee are also commonly injured.[rx][rx]

Radiography

  • Anterior-posterior (AP) and lateral radiographs are typically obtained.[rx] In order to rule out other injuries, hip, pelvis, and knee radiographs are also obtained.[rx] The hip radiograph is of particular importance because femoral neck fractures can lead to osteonecrosis of the femoral head.[rx]
  • Shenton’s line disruption: loss of contour between a normally continuous line from the medial edge of the femoral neck and inferior edge of the superior pubic ramus
  • lesser trochanter is more prominent due to external rotation of the femur
  • femur often positioned in flexion and external rotation (due to unopposed iliopsoas)
  • asymmetry of lateral femoral neck/head
  • sclerosis in fracture plane
  • smudgy sclerosis from impaction
  • bone trabeculae angulated
  • nondisplaced fractures may be subtle on x-ray

Computed Tomography

  • CT may be useful and can give significant information in comparison with that obtained with conventional radiography in the evaluation of complex or occult fractures,[] assessments of fracture healing as well as post-surgical evaluation.[]
  • CT may be indicated for the confirmation of occult fractures suspected on the basis of physical examination when plain films are normal.

Magnetic Resonance Imaging

  • Although this modality is not the first choice in evaluating acute femoral neck fracture, it is a powerful diagnostic tool to assess bony, ligamentous and soft tissue abnormalities associated with these fractures.
  • MRI has proved to be a very important diagnostic tool for delineating perforation of triangular fibrocartilage complex (TFCC),[] perforation of interosseous ligaments of the proximal carpal row, evaluating occult fractures, post-traumatic or avascular necrosis of carpal bones.

Treatment of Femur Neck Fractures

Treatment available can be broadly

  • Skeletal tractionAvailable evidence suggests that treatment depends on the part of the femur that is fractured. Traction may be useful for femoral shaft fractures because it counteracts the force of the muscle pulling the two separated parts together, and thus may decrease bleeding and pain.[rx] Traction should not be used in femoral neck fractures or when there is any other trauma to the leg or pelvis.[rx][rx] It is typically only a temporary measure used before surgery. It only considered definitive treatment for patients with significant comorbidities that contraindicate surgical management.[rx]
  • Get medical help immediately – If you fall on an outstretched arm, get into a car accident or are hit while playing a sport and feel intense pain in your hip area, then get medical care immediately. Necks of femur fracture cause significant pain in the front part of your hip, closer to the base of your back. You’ll innately know that something is seriously wrong because you won’t be able to lift your leg up. Other symptoms include immediate swelling and/or bruising near the fracture, grinding sounds with arm movements and potential numbness and tingling in the leg.
  • Apply ice – After you get home from the hospital necks of femur fractures (regardless if you had surgery or not), you should apply a bag of crushed ice (or something cold) to your injured in order to reduce the swelling and numb the pain. Ice therapy is effective for acute (recent) injuries that involve swelling because it reduces blood flow by constricting local blood vessels. Apply the crushed ice to your radial head fractures  for 15 minutes three to five times daily until the soreness and inflammation eventually fades away
    Lightly exercise after the pain fades – After a couple of weeks when the swelling has subsided and the pain has faded away, remove your arm sling for short periods and carefully move your hip joints in all different directions. Don’t aggravate the necks of femur fracture so that it hurts, but gently reintroduce movements to the involved joints and muscles. Start cautiously, maybe starting with light and then progress to holding light weights (five-pound weights to start). Your necks of femur fracture need to move a little bit during the later phases of the injury to stimulate complete recovery.
  • Practice stretching and strengthening exercises – of the fingers, leg if your doctor recommends them.
  • A splint – which you might use for a few days to a week while the swelling goes down; if a splint is used initially, a cast is usually put on about a week later.
  • A cast – which you might need for six to eight weeks or longer, depending on how bad the break is (you might need a second cast if the first one gets too loose after the swelling goes away.)
  • Get a supportive arm sling – Due to their anatomical position, necks of femur fracture can’t be cast like a broken limb can. Instead, a supportive arm sling or “figure-eight” splint is typically used for support and comfort, either immediately after the injury if it’s just a hairline fracture or following surgery, if it’s a complicated fracture. A figure-eight splint wraps around both hip and the base of your back in order to support the injured hip and keep it positioned up and back. Sometimes a larger swath of material is wrapped around the sling to keep it closer to your body. You’ll need to wear the sling constantly until there is no pain with arm movements, which takes between two to four weeks for children or four to eight weeks for adults.
  • Get a referral to physical therapy – Once you’ve recovered and able to remove your arm sling splint for good, you’ll likely notice that the muscles surrounding your hip and lower chest look smaller and feel weaker. That’s because muscle tissue atrophies without movement. If this occurs, then you’ll need to get a referral for some physical rehabilitation. Rehab can start once you are cleared by your orthopedist, are pain-free, and can perform all the basic arm and necks of femur fracture movements. A physiotherapist or athletic trainer can show you specific rehabilitation exercises and stretches to restore your muscle strength, joint movements, and flexibility
  • Rigid fixation – osteosynthesis with locking plate, hook plate fixation, fixation with a locking plate, coracoclavicular screws, Knowles pin fixation.
  • Flexible fixation – simple k wire fixation, tension band wiring, suture anchors, vicryl tape, dacron arterial graft for coracoclavicular ligament reconstruction.
  • A splint – which you might use for a few days to a week while the swelling goes down; if a splint is used initially, a cast is usually put on about a week later.
  • A cast – which you might need for six to eight weeks or longer, depending on how bad the break is (you might need a second cast if the first one gets too loose after the swelling goes away.)
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Rest your leg

Once you’re discharged from the hospital in an arm sling, your top priority is to rest your necks of femur fracture and not further inflame the injury. Of course, the arm sling not only provides support, but it also restricts movement, which is why you should keep it on even during sleep. Avoiding the temptation to move your shoulder and arm will help the bone mend quicker and the pain fades away sooner.
  • Depending on what you do for a living and if the injury is to your dominant side, you may need to take a couple of weeks off work to recuperate.
  • Healing takes between four to six weeks in younger people and up to 12 weeks in the elderly, but it depends on the severity of the radial head fractures.
  • Athletes in good health are typically able to resume their sporting activities within two months of breaking they’re ulnar styloid depending on the severity of the break and the specific sport.
  • Sleeping on your back (with the sling on) is necessary to keep the pressure off your shoulder and prevent stressing the hip injury.

Eat nutritiously during your recovery

All bones and tissues in the body need certain nutrients in order to heal properly and in a timely manner. Eating a nutritious and balanced diet that includes lots of minerals and vitamins are proven to help heal broken bones of all types, including necks of femur fracture. Therefore focus on eating lots of fresh produce (fruits and veggies), whole grains, lean meats, and fish to give your body the building blocks needed to properly repair your necks of femur fracture. In addition, drink plenty of purified water, milk, and other dairy-based beverages to augment what you eat.

  • Broken bones need ample minerals (calcium, phosphorus, magnesium, boron) and protein to become strong and healthy again.
  • Excellent sources of minerals/protein include dairy products, tofu, beans, broccoli, nuts and seeds, sardines and salmon.
  • Important vitamins that are needed for bone healing include vitamin C (needed to make collagen), vitamin D (crucial for mineral absorption), and vitamin K (binds calcium to bones and triggers collagen formation).
  • Conversely, don’t consume food or drink that is known to impair bone/tissue healing, such as alcoholic beverages, sodas, most fast food items and foods made with lots of refined sugars and preservatives.

Physical therapy

  • Although there will be some pain, it is important to maintain arm motion to prevent stiffness. Often, patients will begin doing exercises for elbow motion immediately after the injury.  After a neck of femur fracture, it is common to lose some leg strength. Once the bone begins to heal, your pain will decrease and your doctor may start gentle hip, knee exercises. These exercises will help prevent stiffness and weakness. More strenuous exercises will be started gradually once the fracture is completely healed.

Follow-up care

  • You will need to see your doctor regularly until your fracture heals. During these visits, he or will take x-rays to make sure the bone is healing in a good position. After the bone has healed, you will be able to gradually return to your normal activities.

Breathing Exercise

  • To elevate breathing problem or remove the lung congestion if needed.

Medication

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Surgery

Type 1 Fractures (Transepiphyseal)

Closed reduction and spica cast immobilization

  • Considered for nondisplaced or minimally displaced fractures up to age 4 years

Internal fixation

  • Appropriate for older children or with displaced fractures
  • Closed reduction or open reduction is performed to achieve anatomic alignment
  • Smooth pin fixation may be acceptable for small, young children when supplemented with a spica cast
  • Cannulated screw fixation is appropriate for older children and adolescents

Type 2 Fractures (Transcervical) and Type 3 Fractures (Cervicotrochanteric)

Closed reduction and spica cast immobilization

  • Considered only for nondisplaced or minimally displaced fractures up to age 4 years

Internal fixation

  • Appropriate for older children or with displaced fractures
  • Closed reduction or open reduction is performed to achieve adequate alignment
  • Smooth pin fixation may be acceptable for small, young children when supplemented with a spica cast
  • Cannulated screw fixation is appropriate for older children and adolescents
    • Crossing the physis may be necessary to achieve adequate fixation
    • If the fixation stops short of the physis, spica cast immobilization should be considered

Type 4 Fractures (Intertrochanteric)

Closed reduction and spica cast immobilization

  • Nondisplaced or minimally displaced fractures up to age 3-4 years
  • Cross-sectional imaging may be necessary to confirm that reduction is adequate and maintained within the cast

Closed reduction, pin fixation, and spica cast immobilization

  • May be considered for children up to age 6 years

Rigid internal fixation

  • Consider for displaced fractures in children greater than age 3 years
  • Closed reduction or open reduction via an anterolateral approach
  • Proximal femoral plate or compression hip screw

Post-operative immobilization is based on fracture type, patient age, and treatment.  A period of 8-10 weeks in a spica cast is recommended for those children who cannot be compliant with a non-weight bearing or partial weight-bearing.  The older adolescent with rigid fixation can begin partial
weight-bearing within 2 weeks.

  • Internal repair using screws. Metal screws are inserted into the bone to hold it together while the fracture heals. Sometimes screws are attached to a metal plate that runs down the femur.

External fixators

  • External fixators can be used to prevent further damage to the leg until the patient is stable enough for surgery.[rx] It is most commonly used as a temporary measure. However, for some select cases it may be used as an alternative to intramedullary nailing for definitive treatment.[rx][rx]

Intramedullary Nailing

  • For femoral shaft fractures, reduction and intramedullary nailing is currently recommended.[rx] The bone is re-aligned, then a metal rod is placed into the femoral bone marrow, and secured with nails at either end. This method offers less exposure, a 98%-99% union rate, lower infection rates (1%-2%) and less muscular scarring.[rx][rx][rx]

Hemiarthroplasty (Uni- and bipolar)

  • Advantages of monopolar [rx] and bipolar arthroplasty [rx] compared to THA include short operation time and quick mobilization of the patient. Good or at least acceptable clinical, functional and radiological results have been reported in a wide array of studies []. However, whether unipolar or bipolar hemiarthroplasty (HA) provides better results is still under debate [].

Bipolar hemiprostheses

  • It consists of a metal cup that serves as an outer head, a metal femoral component, and a polyethylene insert in between. Here, a multiple-bearing principle is effected by creating a double layer of universal motion. The major movement occurs at the inner bearing, as the addition of weight shifts most of the motion to the inner bearing reducing the damaging effect of metal against the acetabular floor. That way, a low-friction layer at the metal head-plastic interface, with much less frictional torque than the one developed at the outer shell acetabular interface is provided [].

Total Hip Arthroplasty

  • In most western European countries and in the U.S., arthroplasty is the mainstay of surgical treatment of intracapsular femoral neck fractures in patients older than 60 to 65 years []. Here, total hip arthroplasty yields good clinical short to long-term results [,] with significantly less pain and better outcomes represented by the quality of life and functional scores [] (SF-36 and WOMAC) compared to hemiarthroplasty []. Along with the improvement of implants, THA has gained attention for the treatment of displaced femoral neck fracture and importance even in countries traditionally treating this group of patients with internal fixation or with unipolar devices.

Rehabilitation

After surgery, the patient should be offered physiotherapy and try to walk as soon as possible, and then every day after that to maximize their chances of a good recovery.[rx]

Complications of Femur Neck Fractures

  • Avascular necrosis
  • Premature physical closure
  • Delayed union/Non-union
  • Blood clots in your legs or lungs
  • Bedsores
  • Urinary tract infection
  • Pneumonia
  • Further loss of muscle mass, increasing your risk of falls and injury
  • Infection—2% to 17%
  • Decubitus ulcers—20%
  • Nonunion at IT—1% to 2%
  • Nonunion at femoral neck—10% to 30%
  • Fracture—3% to 4% (for hemiarthroplasty)
  • Dislocation—1% to 10% (for hemiarthroplasty)
  • Heterotopic ossification—25% to 40% (for hemiarthroplasty)
  • Deep venous thrombosis—50% to 60%
  • Pulmonary embolism—7%
  • Mechanical failure—IT fractures, 12%
  • Osteonecrosis—1% to 17%; early reduction decreases the rate
  • Degenerative joint disease—33% to 50%
  • Sciatic nerve injury—8% to 19%; approximately 50% of patients recover spontaneously
  • Femoral head fracture—7% to 68%

References

Subtrochanteric Femoral Neck Fractures

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