Subcapital Femoral Neck Fractures: Comprehensive Guide to Epidemiology, Classification, & Anatomy

Introduction & Epidemiology

Subcapital femoral neck fractures represent a significant and often devastating injury, particularly within the geriatric population. This fracture pattern involves a break in the femoral neck located intracapsularly, immediately distal to the articular cartilage of the femoral head. Its anatomical proximity to the femoral head and its critical vascular supply renders these fractures prone to complications such as avascular necrosis (AVN) and nonunion, even with optimal management.

Epidemiologically, subcapital femoral neck fractures primarily affect older adults, with incidence rising exponentially with age, peaking after 80 years. The vast majority occur in patients with underlying osteoporosis, often as a result of low-energy trauma, such as a ground-level fall. Women are disproportionately affected, reflecting the higher prevalence of osteoporosis in females. In younger, high-energy trauma cohorts, these fractures are less common but often associated with greater displacement and higher rates of complications due to the severity of the initial insult. The societal and economic burden is substantial, encompassing surgical costs, prolonged hospitalization, rehabilitation, and a notable increase in 1-year mortality rates, which can range from 15% to 30%, comparable to aggressive malignancies.

Fracture classification systems are critical for guiding treatment decisions and predicting outcomes. The Garden classification assesses displacement and impaction from anterior-posterior radiographs:
* Garden I: Incomplete, impacted, valgus fracture. Stable.
* Garden II: Complete but undisplaced fracture. Stable.
* Garden III: Complete, partially displaced, usually varus. Unstable.
* Garden IV: Complete, fully displaced fracture, with the femoral head usually rotated. Highly unstable.

The Pauwels classification, though less frequently used for day-to-day decision-making, describes the angle of the fracture line relative to the horizontal, reflecting the shear forces across the fracture site:
* Pauwels Type I: <30°
* Pauwels Type II: 30°-50°
* Pauwels Type III: >50°
Higher Pauwels angles indicate greater shear stress and an increased risk of nonunion.

The term "subcapital" itself implies an intracapsular location. While the seed content mentions "transcervical" and "basicervical" fractures, these are typically considered distinct entities within the broader category of femoral neck fractures. "Subcapital" specifically refers to fractures at the junction of the femoral head and neck. "Transcervical" describes a fracture through the middle of the femoral neck, and "basicervical" refers to a fracture at the base of the femoral neck, which is technically extracapsular. For the purpose of this discussion, we will focus on true subcapital, intracapsular fractures.

Surgical Anatomy & Biomechanics

A thorough understanding of the surgical anatomy and biomechanics of the proximal femur is paramount for effective treatment of subcapital fractures.

Surgical Anatomy

The femoral neck connects the femoral head to the femoral shaft, forming an angle of inclination (normally 125-135°) and an angle of anteversion (normally 10-20°). The unique geometry allows for a wide range of motion at the hip joint while transmitting significant loads.

1. Vascular Supply: The primary blood supply to the femoral head is predominantly intracapsular, making subcapital fractures particularly vulnerable to vascular disruption.

   • Medial Circumflex Femoral Artery (MCFA): The dominant blood supply (60-70%), originating from the profunda femoris artery, courses posteriorly and superiorly around the femoral neck. Its branches, the retinacular arteries (superior and inferior) , ascend within the synovial folds to supply the majority of the femoral head. These are frequently disrupted in displaced subcapital fractures.
   • Lateral Circumflex Femoral Artery (LCFA): Contributes to the anterior and inferior femoral head supply, but less critical than the MCFA.
   • Artery of the Ligamentum Teres (Foveal Artery): A branch of the obturator artery, located within the ligamentum teres. It provides a variable, often minor, contribution to the femoral head in adults, but can be a crucial supply in children. Its contribution is generally insufficient to maintain viability in cases of complete disruption of retinacular vessels.
   • Intramedullary Vessels: Contribute to the base of the femoral neck but typically do not extend sufficiently into the subcapital region to compensate for retinacular vessel damage.
     Fracture displacement directly correlates with the degree of vascular disruption. Garden IV fractures, with complete displacement, almost invariably sever the retinacular arteries, leading to high rates of AVN.

2. Capsular Attachments: The hip capsule attaches to the intertrochanteric line anteriorly and more proximally on the femoral neck posteriorly. Subcapital fractures are entirely intracapsular, meaning the hematoma forms within the joint capsule. This intracapsular pressure can further compromise residual blood supply to the femoral head.

3. Soft Tissue Envelope:

   • Gluteal Muscles: Gluteus medius and minimus attach to the greater trochanter and are critical abductors. The gluteus maximus is a powerful extensor and external rotator.
   • Short External Rotators: Piriformis, gemelli superior and inferior, obturator internus and externus, and quadratus femoris. These muscles span from the pelvis to the greater trochanter and can impede reduction attempts if spastic.
   • Neurovascular Structures: The sciatic nerve passes posterior to the hip joint, susceptible to injury during posterior approaches. The femoral nerve, artery, and vein are located anteriorly.

Biomechanics

The femoral neck is subjected to significant biomechanical stresses:
1. Compression: Along the medial aspect of the femoral neck.
2. Tension: Along the lateral aspect of the femoral neck.
3. Shear: Particularly evident in high-angle (Pauwels III) fractures.
Normal walking generates forces equivalent to 2.5-3 times body weight across the hip joint. The stability of the fracture depends on the intactness of the cortical bone and the ability of the bone to resist these forces. In osteoporotic bone, the ability to resist these stresses is severely compromised, predisposing to fracture and poor healing. Displacement significantly alters load transmission, leading to increased shear forces at the fracture site, which hinders callus formation and increases the risk of nonunion and implant cutout.

Indications & Contraindications

The management of subcapital femoral neck fractures is highly individualized, balancing patient factors, fracture characteristics, and potential complications. The fundamental distinction lies between osteosynthesis (fixation) and arthroplasty (replacement).

General Considerations:

• Patient Age: This is a primary determinant. Younger patients (generally <60 years) are prioritized for head preservation. Older, active patients may benefit from arthroplasty, while frail, less active elderly patients may undergo hemiarthroplasty.
• Fracture Displacement (Garden Classification): Undisplaced (Garden I & II) fractures are typically candidates for internal fixation. Displaced (Garden III & IV) fractures in the elderly are usually managed with arthroplasty due to high rates of AVN and nonunion with fixation.
• Comorbidities & Physiological Status: American Society of Anesthesiologists (ASA) physical status classification, cognitive function, and overall medical fitness influence the choice of procedure and anesthetic risk.
• Pre-injury Ambulatory Status & Activity Level: A determinant for selecting between hemiarthroplasty and total hip arthroplasty (THA).
• Bone Quality: Osteoporosis significantly impacts fixation stability and long-term outcomes with osteosynthesis.
• Time to Surgery: Urgent reduction and fixation (<6-12 hours) in young patients and displaced fractures are critical to preserving blood supply to the femoral head.

Indications for Operative vs. Non-Operative Management

Contraindications

• Absolute Contraindications to Surgery:
  • Severe, uncorrectable medical comorbidities precluding anesthesia or surgery (e.g., terminal illness with limited life expectancy, severe cardiac or pulmonary failure).
  • Active infection (local or systemic) that cannot be controlled prior to surgery.
• Relative Contraindications to Internal Fixation:
  • Highly comminuted fractures rendering stable fixation impossible.
  • Significant bone loss or severe osteoporosis (T-score < -3.5) predisposing to implant cutout.
  • Delayed presentation of a displaced fracture (e.g., >24-48 hours) in the elderly, increasing AVN risk with fixation.
• Relative Contraindications to Arthroplasty:
  • Active localized infection (periarticular or systemic).
  • Extensor mechanism insufficiency (for THA).
  • Severe neurological conditions (e.g., uncontrolled epilepsy, Parkinson's disease) increasing dislocation risk for THA.

Pre-Operative Planning & Patient Positioning

Meticulous pre-operative planning is critical for optimizing outcomes and minimizing complications.

Pre-Operative Planning

1. Patient Optimization:
   • Medical Clearance: Thorough medical evaluation (cardiac, pulmonary, renal assessment) to optimize patient's physiological status and minimize anesthetic risk.
   • Anemia Correction: Address significant anemia pre-operatively to reduce transfusion requirements.
   • Nutritional Status: Optimize if time permits, especially in chronically ill patients.
   • DVT Prophylaxis: Initiate pharmacological (e.g., low molecular weight heparin) and mechanical (e.g., pneumatic compression devices) prophylaxis upon admission.
   • Antibiotic Prophylaxis: Administer intravenous broad-spectrum antibiotics (e.g., Cefazolin) within 60 minutes prior to incision.
2. Imaging:
   • Standard Radiographs: AP pelvis with both hips, AP and lateral views of the affected hip. These are essential for classification (Garden, Pauwels), templating, and assessing pre-existing arthritis.
   • CT Scan: Routinely indicated for young patients with any displacement or comminution to precisely define fracture morphology, guide reduction maneuvers, and assess fragment orientation. Also useful for templating in complex arthroplasty cases.
   • MRI Scan: Rarely indicated acutely but can be used in ambiguous cases where X-rays are inconclusive for occult fractures, or to assess femoral head viability in delayed presentations or cases of suspected AVN.
3. Templating:
   • For Internal Fixation: Template for cannulated screw length and trajectory or DHS lag screw length and plate size.
   • For Arthroplasty: Crucial for planning implant size (femoral stem, head, and acetabular components for THA), neck length, and offset to restore leg length and hip biomechanics. Use calibrated radiographs or digital templating.
4. Consent: Comprehensive discussion with the patient and/or family regarding the chosen procedure, risks (AVN, nonunion, infection, DVT/PE, limb length discrepancy, dislocation, implant failure), benefits, and expected recovery.

Patient Positioning

The choice of positioning depends on the planned surgical approach (anterior, anterolateral, posterolateral) and the need for traction.

1. For Internal Fixation (ORIF):
   • Fracture Table (Hanaulux or similar): Preferred for closed reduction and percutaneous fixation. Patient is supine.
     • Preparation: Perineal post positioned, unaffected leg abducted and flexed in a well-padded boot, affected leg secured in a traction boot.
     • Reduction Maneuver: Perform gentle traction (5-10 kg) with internal rotation (15°) and slight abduction to achieve reduction under fluoroscopic guidance (Leadbetter maneuver often employed). The C-arm must have unobstructed access for AP, lateral, and oblique views.
     • Padding: Meticulous padding of all bony prominences, perineum, and ankles to prevent pressure sores or nerve palsies.
   • Supine on Standard Table (for open reduction): If closed reduction fails, patient can be positioned supine on a radiolucent table for open reduction via an anterior approach (Smith-Petersen) or limited anterolateral approach.
2. For Arthroplasty (Hemi- or THA):
   • Supine on Standard Radioluscent Table: For direct anterior approach. Requires specialized table attachments for hip extension and rotation. C-arm access is crucial.
   • Lateral Decubitus Position: Standard for posterolateral or anterolateral approaches.
     • Preparation: Patient secured with beanbag or pegs, ensuring stable positioning. Axillary roll for the dependent arm, pillows between the knees, padding of peroneal nerve at fibular head, and dependent iliac crest.
     • C-arm Access: Ensure unrestricted intra-operative fluoroscopy if needed (e.g., for stem insertion, leg length assessment).

Detailed Surgical Approach / Technique

The choice of surgical technique depends on the patient's age, fracture displacement, bone quality, and surgeon preference.

1. Internal Fixation (ORIF) for Young Patients or Undisplaced Fractures in the Elderly

A. Reduction:
* Closed Reduction: The primary goal is anatomical reduction. Performed on a fracture table under fluoroscopic guidance.
* Leadbetter Maneuver: Hip is flexed to 90°, internally rotated maximally, abducted, and then extended while maintaining internal rotation. This attempts to disimpact and derotate the distal fragment relative to the head.
* Gentle Traction & Internal Rotation: Apply longitudinal traction with 15-20° internal rotation and slight abduction. This corrects varus and external rotation deformity.
* Confirmation: AP and lateral fluoroscopic views. Aim for anatomical reduction with restoration of neck length, angle, and anteversion. Garden alignment index on lateral view (anterior and posterior cortices) should be parallel, indicating successful reduction. Any persistent malreduction, particularly varus or posterior angulation, is unacceptable.
* Open Reduction: If closed reduction is unsuccessful after multiple attempts, open reduction is indicated.
* Approach: An anterior (Smith-Petersen or Hueter) or limited anterolateral approach allows direct visualization.
* Capsulotomy: A T-shaped capsulotomy facilitates visualization and irrigation.
* Direct Manipulation: Use bone hooks, periosteal elevators, or femoral neck retractors to achieve anatomical reduction. Temporarily fix with K-wires.

B. Fixation (Cannulated Screws):
* Most Common Method: Multiple (typically three) large-fragment 7.0-7.3mm cannulated screws are the standard.
* Incision: Small stab incisions over the lateral femoral cortex, distal to the greater trochanter.
* Guidewire Placement:
* Under fluoroscopy, place initial guidewire centrally in the femoral head and neck on AP view, and centrally or slightly inferior in the femoral neck on lateral view. Avoid superior placement to prevent vascular injury.
* A second guidewire is placed parallel to the first, usually inferior and posterior, forming an inverted triangle construct (two inferior, one superior, or vice-versa). The goal is to maximize screw purchase in the dense bone of the femoral head and neck, avoiding the fovea.
* The guidewires should extend into the subchondral bone of the femoral head, ideally 5-10 mm from the articular surface.
* Screw Insertion:
* Measure length, pre-drill (if self-tapping screws are not used), and insert fully threaded or partially threaded cannulated screws. Partially threaded screws provide compression across the fracture site.
* Positioning: The most superior screw should be slightly anterior, and the inferior screws slightly posterior, respecting the femoral neck anteversion.
* Compression: Apply controlled compression across the fracture site by slightly over-drilling the distal cortex or by using partially threaded screws.
* Alternative: Sliding Hip Screw (DHS) with Derotation Screw:
* May be considered for basicervical fractures or fractures with significant comminution/osteoporosis.
* A single, centrally placed lag screw provides strong fixation, often supplemented by an anti-rotation screw to prevent head rotation.
* Requires a larger incision and greater soft tissue dissection.
* Closure: Layered closure of fascia, subcutaneous tissue, and skin.

2. Arthroplasty (Hemiarthroplasty or THA) for Displaced Fractures in the Elderly

A. Choice of Arthroplasty:
* Hemiarthroplasty (HA): Replaces the femoral head and neck with a prosthetic component. The acetabulum is left undisturbed.
* Unipolar HA: Single, articulating head. Less common now.
* Bipolar HA: Two articulating surfaces—a small head articulating with a larger polyethylene cup, which in turn articulates with the native acetabulum. Thought to reduce wear on the acetabular cartilage, but evidence of superiority over unipolar is limited.
* Indication: Elderly, less active, significant comorbidities, limited life expectancy.
* Total Hip Arthroplasty (THA): Replaces both the femoral head and neck and resurfaces the acetabulum with a prosthetic cup.
* Indication: Active, healthy elderly patients, minimal comorbidities, pre-existing symptomatic osteoarthritis of the ipsilateral hip, or in situations where THA is deemed superior for long-term function (e.g., highly active individuals >70, but this is debatable vs. hemiarthroplasty in acute fracture).

B. Surgical Approaches:

1. Posterolateral Approach (Kocher-Langenbeck):

   • Internervous Plane: Between gluteus maximus (innervated by inferior gluteal nerve) and gluteus medius/minimus (innervated by superior gluteal nerve).
   • Steps:
     • Incision: Curved skin incision from just posterior to the greater trochanter, extending distally and posteriorly.
     • Fascia: Incise the fascia lata, exposing the gluteus maximus.
     • Muscle Dissection: Split the gluteus maximus fibers bluntly. Retract the muscle anteriorly and superiorly.
     • Short External Rotators: Identify and sharply release the piriformis and obturator internus/gemelli from their insertions on the greater trochanter. Tag these tendons with sutures for later repair. This exposes the posterior capsule.
     • Capsulotomy: Perform a T-shaped or inverted T-shaped capsulotomy.
     • Dislocation: Internally rotate the leg and adduct to dislocate the femoral head.
     • Femoral Head Osteotomy: Resect the fractured femoral head.
     • Femoral Preparation: Ream the femoral canal, broach to the appropriate stem size, and insert the chosen femoral stem (cemented or uncemented).
     • Acetabular Preparation (for THA): Ream the acetabulum, trial component placement, and implant the acetabular cup (cemented or uncemented).
     • Reduction & Closure: Reduce the hip, repair the short external rotators and capsule if possible, close fascia lata, subcutaneous tissue, and skin.
   • Advantages: Excellent visualization, familiar to most surgeons, low risk of nerve injury.
   • Disadvantages: Higher risk of dislocation compared to anterior approaches (though repair of external rotators and capsule reduces this).

2. Anterolateral Approach (Hardinge):

   • Internervous Plane: Between gluteus medius (superior gluteal nerve) and tensor fascia lata (superior gluteal nerve).
   • Steps:
     • Incision: Straight incision centered over the greater trochanter, extending proximally and distally.
     • Fascia: Incise the fascia lata.
     • Muscle Dissection: Split the gluteus medius fibers and detach a portion from the greater trochanter (or perform a trochanteric osteotomy in some variations). The superior gluteal nerve is a concern here.
     • Capsulotomy: T-shaped or H-shaped capsulotomy.
     • Dislocation: Externally rotate and extend the hip to dislocate.
     • Further Steps: Similar to posterolateral approach for femoral/acetabular preparation and component insertion.
   • Advantages: Lower dislocation rate than posterolateral.
   • Disadvantages: Risk of damage to superior gluteal nerve (leading to abductor weakness and Trendelenburg gait), detachment of abductor muscles can lead to heterotopic ossification or abductor insufficiency.

3. Direct Anterior Approach (DAA):

   • Internervous Plane: Between sartorius (femoral nerve) and tensor fascia lata (superior gluteal nerve), accessing the hip capsule directly without detaching muscles.
   • Steps:
     • Incision: Longitudinal incision distal and lateral to the ASIS.
     • Fascia: Incise fascia between TFL and sartorius.
     • Muscle Dissection: Retract TFL laterally and sartorius/rectus femoris medially. Identify the ascending branch of the lateral circumflex femoral artery and ligate/cauterize.
     • Capsulotomy: Longitudinal capsulotomy.
     • Dislocation: Specific maneuvers (e.g., hip extension, external rotation, or specific table positions) are needed to dislocate the hip.
     • Further Steps: Similar to other approaches for femoral/acetabular preparation and component insertion.
   • Advantages: Muscle-sparing, potentially faster recovery, lower dislocation rates.
   • Disadvantages: Technically demanding, steep learning curve, specific operating table requirements, risk of lateral femoral cutaneous nerve injury (meralgia paresthetica), potential for femoral shaft fracture during stem insertion, limited exposure in obese or muscular patients.

C. Cemented vs. Uncemented Implants:
* Cemented: Historically preferred in the elderly due to reliable initial stability in osteoporotic bone. Concerns regarding bone cement implantation syndrome (BCIS) exist but are typically well-managed.
* Uncemented: Increasingly used, especially in younger, more active elderly patients with good bone quality. Relies on press-fit and osseointegration.

Complications & Management

Complications following subcapital femoral neck fractures are frequent and can significantly impact long-term outcomes and patient quality of life.

Common Complications and Salvage Strategies

General Principles of Complication Management:

• Prevention: The cornerstone of complication management. Includes meticulous surgical technique, appropriate implant selection, strict DVT/SSI prophylaxis, and comprehensive post-operative care.
• Early Recognition: Vigilance for signs and symptoms of complications is essential (e.g., worsening pain, fever, swelling, neurological changes).
• Multidisciplinary Approach: Often requires collaboration with infectious disease specialists, internal medicine, physical therapists, and pain management teams.

Post-Operative Rehabilitation Protocols

Rehabilitation is an integral component of successful outcomes following subcapital femoral neck fracture surgery, aiming to restore function, prevent secondary complications, and facilitate a return to pre-injury activity levels where possible. Protocols vary based on the surgical procedure and patient factors.

General Principles

• Early Mobilization: As soon as safely possible, to prevent complications such as DVT/PE, pneumonia, and deconditioning.
• Pain Management: Multimodal analgesia to facilitate participation in therapy.
• Weight-Bearing Restrictions: Tailored to the stability of fixation/prosthesis and bone quality.
• Progressive Strengthening & ROM: Gradual increase in exercises to restore muscle strength and joint mobility.
• Fall Prevention: Crucial, especially in the elderly, involving gait training, balance exercises, and home environment assessment.

1. Following Internal Fixation (ORIF)

• Initial Phase (Weeks 0-6):
  • Weight-Bearing:
    • Undisplaced (Garden I/II): Often protected weight-bearing (PWB) or weight-bearing as tolerated (WBAT) with crutches/walker, depending on surgeon preference and bone quality. Some surgeons advocate for touch-down weight-bearing (TDWB) initially.
    • Displaced (Garden III/IV): Typically TDWB or non-weight-bearing (NWB) for 6-12 weeks to protect the fracture fixation and allow for early healing, especially in cases of questionable stability.
  • Exercises: Gentle ankle pumps, quadriceps sets, gluteal sets. Passive and active-assisted range of motion (ROM) within pain limits. No active hip abduction, adduction, or rotation against resistance to protect the fracture site.
  • Education: Instruction on safe transfers, use of assistive devices, and DVT precautions.
• Intermediate Phase (Weeks 6-12):
  • Weight-Bearing: Progress from PWB to WBAT if radiographs show signs of healing (callus formation, trabecular bridging) and pain allows.
  • Exercises: Gradual introduction of active ROM exercises. Isometric hip strengthening. Gentle resisted exercises for hip flexors, extensors, and abductors. Closed-chain exercises (e.g., mini-squats).
  • Gait Training: Progress from walker to crutches, then to a single cane, with emphasis on normal gait pattern.
• Advanced Phase (Months 3-6+):
  • Weight-Bearing: Full weight-bearing.
  • Exercises: Progressive resistance exercises for all hip muscle groups. Balance and proprioception training. Return to light recreational activities.
  • Outcome: Radiographic union is typically assessed at 3-6 months. Hardware removal may be considered after 12-18 months, particularly in younger, active individuals or if hardware prominence causes symptoms.

2. Following Arthroplasty (Hemiarthroplasty or THA)

• Initial Phase (Days 0-2 weeks):
  • Weight-Bearing: Usually WBAT immediately after surgery, unless there are specific intraoperative concerns (e.g., uncemented stem in very poor bone quality, intraoperative fracture).
  • Exercises: Immediate initiation of ankle pumps, quadriceps sets, gluteal sets. Active and passive ROM exercises to the hip, knee, and ankle.
  • Functional Training: Instruction on bed mobility, transfers, and ambulation with an assistive device (walker).
  • Precautions (for THA, particularly posterior approach): Avoid hip flexion >90°, internal rotation past neutral, and adduction past midline to prevent dislocation. These precautions are typically less stringent or absent for DAA.
• Intermediate Phase (Weeks 2-6):
  • Weight-Bearing: Continue WBAT with assistive device.
  • Exercises: Progressive strengthening of hip abductors, extensors, and flexors. Light resistance exercises. Balance and gait training with emphasis on minimizing Trendelenburg gait.
  • Stair Training: Begin stair negotiation.
• Advanced Phase (Weeks 6-12+):
  • Weight-Bearing: Progress to full weight-bearing, wean off assistive devices as strength and balance improve.
  • Exercises: Advanced strengthening, functional exercises, balance training. Return to more demanding activities.
  • Dislocation Precautions: Often relaxed after 6-12 weeks for THA, depending on surgeon and patient compliance.
  • Long-Term: Regular exercise, weight management, and fall prevention strategies are encouraged.

Summary of Key Literature / Guidelines

Evidence-based guidelines inform the contemporary management of subcapital femoral neck fractures. Major societies such as the American Academy of Orthopaedic Surgeons (AAOS) and NICE (National Institute for Health and Care Excellence) provide recommendations.

1. Fixation vs. Arthroplasty in the Elderly

• Displaced Fractures (Garden III/IV): Numerous randomized controlled trials (RCTs) and meta-analyses consistently demonstrate superior outcomes for arthroplasty (HA or THA) over internal fixation in displaced femoral neck fractures in the elderly.
  • Evidence: Arthroplasty is associated with lower rates of reoperation (due to AVN or nonunion), better functional outcomes, and less pain, albeit with a slightly higher risk of early complications like infection or dislocation.
  • Recommendation: Arthroplasty is the preferred treatment for displaced subcapital femoral neck fractures in active, community-dwelling elderly patients.
• Undisplaced Fractures (Garden I/II): Internal fixation (typically cannulated screws) remains the standard of care for these stable fractures.
  • Evidence: Fixation offers good results with lower surgical invasiveness and complications compared to arthroplasty. Reoperation rates for AVN or nonunion are lower than for displaced fractures, but still a concern (around 10-15%).
  • Recommendation: Internal fixation for undisplaced subcapital fractures in all age groups.

2. Hemiarthroplasty vs. Total Hip Arthroplasty (THA) for Displaced Fractures in the Elderly

• THA Advantages: For active, healthy, and cognitively intact elderly patients, THA generally yields better functional outcomes, lower reoperation rates, and less pain compared to HA. This is particularly true for patients with pre-existing symptomatic arthritis of the ipsilateral hip.
• HA Advantages: HA is simpler, quicker, and associated with lower early dislocation rates and often preferred in less active, frail patients with significant comorbidities, limited life expectancy, or who are institutionalized. It carries a slightly lower surgical burden and shorter operative time.
• Evidence: Meta-analyses show that THA results in better functional outcomes and a lower reoperation rate than HA, but often at the expense of a slightly higher early dislocation rate in some studies, particularly with the posterolateral approach. The decision often hinges on patient activity level, comorbidities, and life expectancy.
• Recommendation: THA for physiologically younger, active elderly patients without significant cognitive impairment; HA for older, less active, or frail patients with comorbidities.

3. Cemented vs. Uncemented Femoral Stems in Arthroplasty

• Evidence: For HA, cemented stems are generally preferred in the elderly, particularly those with poor bone quality, due to reliable immediate stability and lower rates of periprosthetic fracture. Uncemented stems can be used in patients with good bone quality.
• Recommendation: Cemented HA is often recommended as the safer and more reliable option for most elderly fracture patients. For THA, the choice between cemented and uncemented is often based on bone quality, surgeon preference, and patient factors, similar to elective THA.

4. Surgical Timing

• Evidence: Prompt surgical intervention (within 24-48 hours) for most femoral neck fractures is associated with reduced mortality, fewer complications (DVT/PE, pneumonia), and improved functional outcomes. For young patients with displaced fractures, urgent reduction and fixation (<6-12 hours) are critical to optimize the chances of femoral head viability.
• Recommendation: Operate on subcapital femoral neck fractures as soon as medically optimized, ideally within 24-48 hours of admission.

5. Approach for Arthroplasty

• Evidence: While each approach (posterolateral, anterolateral, direct anterior) has specific advantages and disadvantages regarding dislocation rates, nerve injury, and muscle damage, no single approach has definitively proven superior for all fracture patients. Surgeon familiarity and expertise with a particular approach are often more critical determinants of success than the approach itself.
• Recommendation: Choose the approach with which the surgeon is most proficient, considering patient-specific factors such as body habitus and comorbid conditions.

In conclusion, the management of subcapital femoral neck fractures requires a nuanced, patient-centered approach, integrating robust evidence with clinical judgment. Continuous assessment of patient status, meticulous surgical execution, and comprehensive post-operative rehabilitation are paramount to achieving the best possible outcomes in this challenging patient population.