Left Hip Hemiarthroplasty for Femoral Neck Fracture

Abstract

Hip fractures are a major cause of morbidity and mortality, especially among older patients. They also account for a significant portion of healthcare spending and other non-medical costs. These fractures can be classified into various types based on the parts of the femoral head and neck affected, and fixation options are dependent on both patient and injury characteristics. In this video, Dr. Agarwal-Harding takes us through a hip hemiarthroplasty for a left femoral neck fracture, highlighting various guiding principles and surgical considerations.

Keywords

Femoral neck fractures; hip fractures; hemiarthroplasty; fracture.

Case Overview

Background

Hip fractures are one of the most common musculoskeletal injury presentations to the emergency department in the United States, especially among older individuals.¹ The incidence of these fractures is rising and is projected to account for over $9–$20 billion in healthcare spending within the next 20 years.^2,3

Hip fractures are classified into femoral neck, intertrochanteric, and subtrochanteric based on anatomical location. Femoral neck fractures are further classified as intracapsular and extracapsular in relation to the hip joint capsule, and non-displaced or displaced depending on the degree of separation of the fracture fragments.² These classifications are relevant, as they guide treatment decision-making.⁴

Management can be conservative or surgical; however, conservative management is rarely indicated as it is associated with poor outcomes.^5–7 The type of fixation modality is selected based on a combination of the fracture profile, specific patient factors, and postoperative rehabilitation considerations. Hemiarthroplasty is the standard of care in older patients with displaced, intracapsular femoral neck fractures.

Focused History of the Patient

The patient is a 71-year-old gentleman who presented to the emergency department with left hip pain following a fall from standing at home. Notably, he had a past medical history of acute myeloid leukemia treated with chemotherapy and bone marrow transplant years prior, complicated by graft-versus-host disease. He was a community ambulator with a cane at baseline. A relapse of his leukemia was unfortunately identified during follow up from his surgery, but this was not known at the time of presentation.

Physical Exam

On examination, he was well-appearing in no acute distress. Vital signs were stable and he was complaining of isolated left hip pain. Left lower extremity exam revealed intact skin, no obvious deformity, with mild edema and ecchymosis about the left hip. Any range of motion and palpation of the left hip was avoided as this caused severe pain. He had no tenderness to palpation of the thigh, knee, leg, or ankle. Thigh and leg compartments were soft and compressible. His pelvis was stable to AP and lateral compression. He was distally neurovascularly intact.

Imaging

Anterior-to-posterior (AP) views of the pelvis and lateral hip radiographic views are standard for the diagnosis of hip fractures.⁸ Generally, cross-table laterals are standard, and frog laterals should be avoided as they cause pain. While radiographs are usually sufficient to make the diagnosis, magnetic resonance imaging (MRI) and bone scans may be used when there is strong clinical suspicion of a fracture but radiographs are negative or equivocal.⁹ For this patient, an additional CT scan was performed given his oncologic history to evaluate for any pathologic lesion of the proximal femur that may have caused his fracture—no such lesion was identified. A diagnosis of a displaced left femoral neck fracture was made in the emergency department after radiographic exam, and he was admitted for treatment.

Natural History

Timely fixation of hip fractures is crucial, as they have been associated with poor outcomes when left untreated.^5,6 From a hip perspective, the delicate vascular supply to the femoral head can be disrupted by a displaced femoral neck fracture, leading to eventual osteonecrosis of the femoral head.² From a patient perspective, there is an increased risk of multi-system complications and mortality that has been attributed to a release of thrombotic factors and immobilization.² However, there are multiple studies that have demonstrated a reduction in functional status and an increased risk of morbidity and mortality despite timely fracture repair.^8,10 These findings are the subject of ongoing research to improve outcomes, especially among older adults.

Options for Treatment

Intracapsular femoral neck fractures should be managed surgically, either with internal fixation of the fracture or arthroplasty. Internal fixation, typically with multiple cancellous screws or a sliding hip screw, is favored in younger patients to preserve native anatomy. Arthroplasty is generally preferred in older patients who have poor bone quality, as in the index patient, and has been shown to lead to a lower risk of reoperations, better quality of life, and improved functional outcome compared to internal fixation among older patients.^11,12 Many studies have compared the use of total hip arthroplasty versus hemiarthroplasty, the results of which have been variable.^13–16 The authors propose that use of hemiarthroplasty versus a total hip arthroplasty should depend on a patient’s baseline acetabulum wear and preinjury hip pain, the surgeon’s comfort with performing the procedure, and the patient’s baseline activity level and functional demands. Patients over the age of 70 with multiple medical comorbidities and low functional demands are generally indicated for hip hemiarthroplasty.

Rationale for Treatment

The risk of complications with untreated hip fractures is considerable, with a four-fold higher risk of mortality among untreated patients at one year.⁵ Additionally, fixation with a load bearing or sharing implant facilitates early mobilization, which has also been shown to improve survival and recovery of functional status following injury.⁶

Special Considerations

In patients with malignancy, it is important to assess for metastasis and additional lesions, as decisions regarding patient management may be greatly impacted.¹ About 50% of all long-bone pathologic fractures occur in the proximal femur, the majority of which affect the pertrochanteric region. The goal of surgery in proximal femoral metastases is to relieve pain, restore function, and stabilize the limb from further fracture.¹⁷ For most femoral head and neck lesions, hemiarthroplasty is the preferred treatment.¹⁷

Discussion

Hip Fracture Overview and Epidemiology

Globally, about 4.5 million people have hip fractures each year, which are a significant cause of disability.^2,18 Of these, an overwhelming majority occur in elderly patients and result from low-energy falls, commonly leading to hospitalization.¹⁹ Furthermore, various projections from around the world predict a significant increase in the incidence of these fractures in the years to come, associated with an aging global population, including in low- and middle-income countries.^4,8

Epidemiological studies in the United States have shown over 250,000 hip fractures occur annually, being most common among white, elderly, and female patients.^1,3 Interestingly, while incidence is higher in female patients, mortality rate is higher among males.³ Additional risk factors for these fractures include lower educational level, osteoporosis, steroid use, lack of weight-bearing exercise, history of diabetes, among others.²⁰

Femoral neck fractures are further subdivided into subcapital, transcervical and basicervical depending on the location of the primary fracture line.^1,21 Other classifications exist for femoral neck fractures, including the Garden classification, which classifies the fracture by completeness and displacement, and Pauwels classification, which classifies the fracture by the angle of the fracture line compared to the horizontal.^4,22 Both the Garden and Pauwels classification correspond to risk of fracture displacement, and therefore inform internal fixation methods.

Options for Treatment (Total Hip Arthroplasty vs Hemiarthroplasty)

The fracture's location in relation to the hip joint capsule is clinically significant and helps determine which fixation method is most appropriate. The blood supply to the femoral head traverses the intracapsular area, predisposing to osteonecrosis and poor healing when this region is disrupted, as seen in femoral neck fractures. The mechanism can be direct from rupture of primary vessels, or indirect from disruption of secondary vessels with displacement and increased capsular pressure leading to compromise of vascular perfusion.^4,23

Open reduction and internal fixation may be used to fix femoral neck fractures in younger patients,²⁴ with arthroplasty being favored for older patients. The choice between a total hip arthroplasty and hemiarthroplasty is made based on a number of factors aimed at presenting the patient with the best chance of optimal functional recovery.^4,25 Some advantages of hemiarthroplasty over total hip arthroplasty include reduced operative time, reduced intraoperative blood loss, and a lower risk of dislocation;²⁵ however, recent data suggests that total hip arthroplasty may offer better functional outcomes4 with no statistically-significant differences in mortality or other complications.^13,26,27

In hemiarthroplasty, two types of femoral head designs are used: unipolar and bipolar. While available evidence points to better functional outcomes and slower acetabular wear with bipolar heads, these differences are not sustained long term.^28,29 Another technical point to note is the use of cement during fixation. Cement use is recommended, and has been noted to reduce the incidence of periprosthetic fractures;³⁰ however, it is important to be aware of some of the complications that may arise with its use, including but not limited to intraoperative hypotension and cardiovascular compromise.³¹

Timing of Surgery

It is generally recommended that hip fracture repair surgery take place as soon as possible, usually within 24–48 hours of admission;^32,33 however, it should be noted that many individuals who suffer hip fractures also have additional comorbidities that require optimization to reduce the risk of perioperative mortality. We recommend a case-by-case approach for the perioperative management of each patient while adhering to current evidence-based guidelines such as fracture comanagement programs with a geriatric medicine service³⁴ to optimize patients and get safely to surgery in a timely fashion. Preoperative planning before arthroplasty surgeries can also significantly minimize the risk of iatrogenic femur fractures. While not mandatory, this is a practice that every surgeon should consider to enhance patient safety and surgical outcomes.

Surgical Approach

For this patient, we began by making a curvilinear longitudinal incision over the greater trochanter of the left lateral hip. We then took an anterolateral approach to the hip by peeling off a full-thickness sleeve of the anterior one-third of the abductor insertion confluent with the anterior one-third of the vastus lateralis after which we incised the anterior hip capsule and exposed the femoral neck fracture. The femoral head was removed, the acetabulum was irrigated to remove any small bone fragments, and the femoral head was measured on the back table. The proximal femoral neck cut was then made using the template to ensure the appropriate height of the cut. We inserted a trial head into the acetabulum to confirm the appropriate size. We then gained access to the femoral canal by flexing and externally rotating the lower extremity at the hip.

The femur was then broached until a good press-fit was achieved with a size 5 stem. We subsequently relocated the hip with trial components in place to confirm adequate tension of the soft tissues, equal leg lengths, and hip joint stability with external rotation and flexion and internal rotation of the hip. We shot a flat plate x-ray at this time, which confirmed appropriate leg lengths and size of the femoral component. The hip was then dislocated and the trial components were removed. A cement restrictor was then placed to the appropriate depth, a sponge was placed into the acetabulum, and the femoral canal was washed and packed with sponges.

Once the mixed cement was of the appropriate consistency, the sponges were removed from the femoral canal and we confirmed that the patient's blood pressure was appropriate with systolic blood pressures greater than 120 mmHg. The proximal femoral canal was then cemented with pressurization with the patient tolerating this well. A size 5 cemented Summit stem was then inserted at the appropriate neutral version relative to the femoral canal. This was held into position until the cement was fully hardened, which was checked with a scalpel blade. The stem neck was then cleaned thoroughly, the femoral head was applied, and malleted in for taper fit on the neck.

The sponge was removed from the acetabulum, and the hip was reduced. Examination confirmed stable reduction with no dislocation with external rotation and flexion internal rotation of the hip.  Flat plate x-ray was performed and confirmed appropriate position and cementation of the stem. The wound was then thoroughly irrigated with normal saline after which the anterior capsule, the iliotibial band, and the Scarpa's fascia layer were closed. The wound was irrigated, and the skin was closed. Dry sterile dressings were applied, the patient was transferred safely to his hospital bed and brought to the recovery room in stable condition.

It is important to emphasize that each individual who touches or handles the implant or cement must change gloves to maintain strict adherence to aseptic techniques.

Postoperative Management and Rehab

The impact of early mobilization cannot be overemphasized, irrespective of which management modality is utilized.² Additionally, because the patient population most commonly impacted by hip fractures are likely to have additional comorbidities, multidisciplinary care of these patients may help in improving outcomes. Other facets of care include prevention of thromboembolic complications, optimization of metabolic status, and fall prevention education.⁴

Patients after hip hemiarthroplasty typically may weight bear as tolerated and will be up and out of bed on postoperative day 1. An anterolateral approach to the hip joint has a low risk of dislocation, but some would advocate for precautions and avoiding certain ranges of motion of the hip depending on the approach to lower dislocation risk. We typically start patients on subcutaneous enoxaparin daily for venous thromboembolism prophylaxis. In our institution, many patients who have hemiarthroplasty follow their hospitalization with a short stay at an inpatient rehabilitation center, where patients spend up to 3 hours a day on stretching, strengthening, and proprioception exercises.

Patients return to the clinic after 2–3 weeks for staples/suture removal. X-rays are often not necessary at 2 weeks, but are performed at 6 weeks.³⁵

Equipment

• Depuy-Synthes Summit hemiarthroplasty set with cement.

Disclosures

Nothing to disclose.

Statement of Consent

The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.