Hip Fractures: The Complete Management Guide

Hip fractures (Neck of Femur / NOF fractures) represent the absolute bread and butter of orthopaedic trauma. For anyone navigating their orthopaedic surgery training, mastering this topic is not optional. It is the most common reason for admission to an orthopaedic trauma ward and represents a critical intersection of surgical biomechanics, geriatric medicine, and health economics. These injuries are classic fragility fractures, frequently signaling the end of independent living for many elderly patients and carrying a one-year mortality rate that rivals many major cancers.

For your fellowship exam preparation, this is a Mandatory Pass topic. You must know the literature, the nuanced classifications, the surgical algorithms, and the complications cold. Examiners will not forgive a fundamental misunderstanding of hip fracture biomechanics, nor will they accept a purely operative approach that ignores the complex medical needs of these frail patients.

1. Anatomy and Blood Supply

The fundamental decision in hip fracture management—Fix vs. Replace—hinges entirely on the integrity of the blood supply to the femoral head. Understanding this vascular anatomy is a cornerstone of surgical education.

• Medial Circumflex Femoral Artery (MCFA): The primary workhorse of the femoral head's blood supply. It arises from the profunda femoris, courses posteriorly between the pectineus and iliopsoas, and passes between the obturator externus and short external rotators. It gives off the lateral epiphyseal (retinacular) vessels of Weitbrecht, which perforate the capsule at the base of the neck and travel subsynovially to the head.
• Lateral Circumflex Femoral Artery (LCFA): Provides a lesser supply via the anterior retinacular vessels, primarily perfusing the anterior and inferior portions of the head.
• Ligamentum Teres (Artery of the Ligamentum Teres): Derived from the obturator artery. While crucial in pediatric orthopaedics, its contribution is negligible in the adult population (supplying less than 10-20% of the head).

The Capsule's Role: The hip capsule attaches to the intertrochanteric line anteriorly and the femoral neck posteriorly (roughly 1cm proximal to the intertrochanteric crest).

• Intracapsular fractures (Subcapital, Transcervical) tear the ascending retinacular vessels, directly endangering the blood supply and resulting in a high risk of avascular necrosis (AVN). Furthermore, the synovial fluid within the joint bathes the fracture site, washing away the fracture hematoma and inhibiting primary bone healing.
• Extracapsular fractures (Intertrochanteric, Subtrochanteric) preserve the retinacular blood supply and occur in an area of robust, well-vascularized cancellous bone with a thick periosteum, leading to excellent healing potential.

2. Intracapsular Fractures

Intracapsular fractures require a nuanced approach based on patient age, physiological demand, and fracture displacement.

Classification Systems

1. Garden Classification Based on the displacement seen on the anteroposterior (AP) radiograph, specifically looking at the primary compressive trabeculae.

• Type I: Incomplete / Valgus impacted. (Considered stable, trabeculae angulated into valgus).
• Type II: Complete, Non-displaced. (Considered stable-ish, trabeculae are interrupted but not angulated).
• Type III: Complete, Partially displaced. (The femoral head is tilted into varus).
• Type IV: Complete, Fully displaced. (The femoral head completely dissociates from the acetabulum and aligns with the acetabular trabeculae).

Simpler Clinical System: In modern practice, we often simplify this to Non-Displaced (I/II) versus Displaced (III/IV), as this dictates the management pathway.

2. Pauwels Classification Highly relevant for young patients, this system classifies based on the angle of the fracture line relative to the horizontal plane. It dictates the biomechanical shear forces across the fracture.

• Type I: < 30 degrees (More compressive forces, favorable for healing).
• Type II: 30 to 50 degrees.
• Type III: > 50 degrees (High shear forces, very high risk of non-union and varus collapse).

Management Algorithm

A. Undisplaced (Garden I/II):

• Treatment: Fixation in situ using Multiple Cannulated Screws (MCS) or a Dynamic Hip Screw (DHS).
• Reason: The goal is to preserve the native femoral head. Because the fracture is undisplaced, the vascularity is often preserved, leading to a much lower risk of AVN and Non-union compared to displaced variants.
• Controversy: There is an ongoing debate regarding the frailest, oldest patients. Some orthopaedic surgeons argue for primary Hemiarthroplasty in the very elderly with Garden I/II fractures to absolutely eliminate the risk of a secondary operation if the fixation fails or AVN develops down the line.

B. Displaced (Garden III/IV): The management here bifurcates sharply based on physiologic age.

• Young (< 60-65 years): URGENT FIXATION. The prime directive is to save the native head. This is an orthopaedic emergency. Every hour counts. Attempt a closed reduction on the traction table. If an anatomic or slight valgus reduction cannot be achieved closed, you must proceed to an Open Reduction (via a Watson-Jones or Smith-Petersen approach). Fixation is typically achieved with a DHS + derotation screw or an inverted triangle of cannulated screws.

• Elderly (> 65 years): REPLACE. The risk of AVN or non-union after fixing a displaced intracapsular fracture in an older adult is unacceptably high (~30-40%). Arthroplasty allows immediate full weight-bearing and minimizes the need for revision surgery.
  • Hemiarthroplasty: The workhorse for low-demand patients, those with cognitive impairment, or those with limited life expectancy. Unipolar or Bipolar heads can be used; evidence shows little long-term functional difference, though bipolar may theoretically reduce acetabular wear.
  • Total Hip Arthroplasty (THA): Reserved for the "Active Elderly."
    • NICE Guidelines Criteria for THA: The patient must be able to walk independently out of doors with no more than a stick, be cognitively intact, and be medically fit for anesthesia.
    • The Evidence: The HEALTH Trial (NEJM) confirmed that while THA offers slightly better functional scores and lower re-operation rates than hemiarthroplasty for independent patients, it carries a higher risk of dislocation.

3. Extracapsular Fractures (Intertrochanteric & Subtrochanteric)

Extracapsular fractures occur through the vascular cancellous bone of the trochanteric region. Non-union is rare, but malunion (varus collapse, shortening, external rotation) is a significant risk if the wrong implant is chosen or reduction is poor.

Classification

1. Evans Classification (Simplified)

• Stable: The posteromedial cortex (the lesser trochanter / calcar region) is intact. Once reduced, the fracture resists varus collapse.
• Unstable: Characterized by posteromedial comminution, reverse obliquity patterns, or subtrochanteric extension. These fractures will collapse into varus if loaded eccentrically.

2. AO/OTA Classification (31A)

• 31A1: Simple, two-part fractures (Stable).
• 31A2: Multifragmentary with posteromedial comminution (Unstable).
• 31A3: Reverse oblique or transverse fracture lines (Highly unstable).

Management Algorithm

A. Stable Intertrochanteric (Evans Stable / 31A1):

• Gold Standard: Sliding Hip Screw (Dynamic Hip Screw / DHS).
• Biomechanics: The DHS allows controlled, dynamic compression across the fracture site as the patient weight-bears. The lag screw slides within the barrel, impacting the fracture fragments. It is highly effective and significantly less expensive than intramedullary devices.

B. Unstable / Reverse Oblique / Subtrochanteric (Evans Unstable / 31A2 / 31A3):

• Gold Standard: Cephalomedullary Nail (e.g., Gamma Nail, PFN).
• Biomechanics: A nail is a load-sharing intramedullary device. Because it sits within the canal, its mechanical axis is much closer to the hip joint's center of rotation compared to a lateral plate. This shorter lever arm dramatically reduces the bending moments on the implant, making it vastly superior for unstable patterns or reverse oblique fractures where a DHS would simply allow the shaft to medialize and fail.

Subtrochanteric Fractures: The Deforming Forces

A classic viva topic in orthopaedic surgery training is the deforming forces acting on a subtrochanteric fracture:

1. Proximal Fragment: Pulled into Flexion (by the Iliopsoas), Abduction (by Gluteus medius/minimus), and External Rotation (by the short external rotators).
2. Distal Fragment: Pulled into Adduction and Shortened (by the adductor magnus/longus/brevis) and extended (by the gastrocnemius). The key to surgical success is aligning the distal fragment to the uncompromising, flexed, and abducted proximal fragment.

4. Surgical Technical Pearls

Meticulous surgical technique separates a good outcome from a catastrophic mechanical failure.

Tip-Apex Distance (TAD)

Described by Baumgaertner in 1995, the TAD is the single most important metric for evaluating lag screw placement in both DHS and cephalomedullary nails. It is the sum of the distance from the tip of the lag screw to the apex of the femoral head on both the AP and Lateral radiographic views.

• The Golden Rule: The combined TAD must be < 25mm.
• Clinical Consequence: A TAD > 25mm is the strongest independent predictor of lag screw "cut-out" (the screw migrating through the superior aspect of the femoral head, destroying the joint and resulting in fixation failure).
• CalTAD: For intramedullary nails, many surgeons now advocate for the Calcar referenced TAD (CalTAD), where the lag screw is placed slightly inferiorly on the AP view to rest on the dense bone of the calcar, rather than perfectly dead-center.

Reduction Maneuvers

Never accept a varus reduction. Varus alignment increases the shear forces across the fracture and significantly increases the bending moment on your implant, virtually guaranteeing failure.

• Acceptable: An anatomic reduction is ideal, but a slight valgus reduction is acceptable and actually protective against mechanical failure.
• The Leadbetter Maneuver: To achieve closed reduction, flex the hip and internally rotate it to disengage the fragments, then apply longitudinal traction and bring the leg into slight abduction and internal rotation to lock the reduction in place.

5. Medical Management (Orthogeriatrics)

Fixing the bone is only half the job. Hip fracture care is a quintessential team sport, requiring seamless integration with geriatricians, anesthetists, and allied health professionals. A surgical technical triumph is meaningless if the patient dies of an undiagnosed pneumonia on post-op day three.

• Time to Surgery: The current global standard is surgery within 36-48 hours of admission. Delaying surgery significantly increases 30-day and 1-year mortality, primarily due to prolonged immobility leading to DVT, PE, pneumonia, and pressure sores. The recent HIP ATTACK trial looked at accelerated surgery (< 6 hours); while it didn't drastically change mortality compared to standard care, it showed benefits in reducing delirium and severe pain.
• Anticoagulation: Do not delay surgery greater than 48 hours simply to reverse a slightly elevated INR unless it is extreme. For patients on modern DOACs/NOACs, follow strict local hematology protocols regarding cessation and bridging.
• Pain Management & Nerve Blocks: The Fascia Iliaca Compartment Block (FICB) is an absolute game-changer. Administered in the emergency department, it provides excellent opioid-sparing regional analgesia, significantly reducing the incidence of opiate-induced delirium in the elderly.
• Secondary Prevention: A fragility fracture is a sentinel event. Every patient over 50 with a low-trauma hip fracture must be evaluated for osteoporosis (DEXA scan) and initiated on bone-sparing agents (e.g., Bisphosphonates or Denosumab) prior to discharge to prevent the devastating contralateral hip fracture.

6. Complications

You must be able to quote the complication rates confidently to patients, families, and examiners.

• Mortality: Approximately 10% at 30 days and up to 30% at 1 year. You must clearly communicate to the family that a hip fracture is a life-threatening, systemic medical event, not just a broken bone.
• Avascular Necrosis (AVN) & Non-union: High in displaced intracapsular fractures (up to 40% if fixed), very low in extracapsular fractures (1-2%).
• Infection: Superficial and deep infection rates sit around 1-3%. Meticulous soft tissue handling and appropriate prophylactic antibiotics are essential.
• Dislocation: Primarily a risk after Hemiarthroplasty or THA. Historically higher with the posterior approach, which is why many trauma surgeons utilize the direct lateral (Hardinge) approach for hip fractures, despite the risk of postoperative limp.
• Cut-out: The primary mode of mechanical failure following DHS or nail fixation, almost exclusively tied to poor surgical reduction (varus) or a poor Tip-Apex Distance (> 25mm) in osteoporotic bone.

Conclusion

Hip fracture management is highly protocol-driven, but requires sharp clinical judgment to navigate the exceptions. Mastering this topic is not merely an academic exercise for your fellowship exam preparation; it is essential for providing safe, high-quality care to a vulnerable patient population.

1. Classify the Fracture: Intracapsular vs. Extracapsular. Displaced vs. Undisplaced. Stable vs. Unstable.
2. Assess the Patient: Physiologic age, cognitive baseline, pre-injury mobility, and medical comorbidities.
3. Select the Implant: Cannulated Screws, DHS, Cephalomedullary Nail, Hemiarthroplasty, or THA.
4. Optimize Logistics: Ensure surgery occurs safely within 48 hours under shared orthogeriatric care.

Clinical Pearl: In any oral examination scenario, always explicitly mention the "Multidisciplinary Team" (Orthopaedics, Orthogeriatrics, Physiotherapy, Occupational Therapy, and Social Work). Demonstrating that you understand hip fracture care extends beyond the operating theater is the hallmark of a mature, consultant-level candidate.

References

1. Bhandari, M., et al. (2019). "Total Hip Arthroplasty or Hemiarthroplasty for Hip Fracture (HEALTH)." New England Journal of Medicine.
2. Baumgaertner, M. R., et al. (1995). "The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip." The Journal of Bone and Joint Surgery.
3. National Institute for Health and Care Excellence (NICE) [NG124]. (2011, updated 2023). "Hip fracture: management."
4. Costa, M. L., et al. (2022). "Cemented versus uncemented hemiarthroplasty for intracapsular hip fracture (WHiTE 5)." The Lancet.
5. Palm, H., et al. (2007). "Integrity of the lateral femoral wall in intertrochanteric hip fractures: an important predictor of a reoperation." The Journal of Bone and Joint Surgery.