Clinical anatomy and its significance
The proximal section has specific conditions that directly affect healing. First, the femoral neck is completely devoid of periosteum. Second, the head and a significant part of the neck are located inside the capsule of the hip joint.
The blood supply to this area is extremely vulnerable. It is provided by three main sources, but the artery of the ligament of head of femur obliterates with age. Blood supply comes predominantly from vessels penetrating the neck from the capsule attachment site and the intertrochanteric region. Clinical rule: the more proximal the fracture line (the closer it is to the articular cartilage of the head), the worse the blood supply to the fragment. This is why intracapsular injuries heal with difficulty, often complicated by avascular necrosis. The trochanteric area, however, is richly supplied by powerful surrounding muscles, which ensures good bone healing.
Classification and symptoms
According to the universal classification, injuries of zone 31 are divided into extracapsular (trochanteric area — type A) and intracapsular (neck — type B, head — type C).
The typical clinical presentation of a displaced injury includes:
- Sharp pain in the groin area or projection of the greater trochanter, increasing with axial load on the leg.
- External rotation — the foot of the injured leg is unnaturally turned outward.
- “Stuck heel” sign — the patient is unable to independently lift a straight leg above the bed.
- High-standing greater trochanter syndrome — Shoemaker's line (from the trochanter through the anterior superior iliac spine) passes below the navel.
- Relative shortening of the limb by 2–3 cm in the absence of true (absolute) shortening.
Special attention should be paid to impacted (valgus) fractures. In these cases, symptoms are mild, leg support is not impaired, and the person can walk independently. This often leads to diagnostic errors and "disimpaction" — secondary displacement of fragments.
Principles of treatment
Treatment tactics depend on the fracture plane, blood supply status, and the patient's age.
Treatment of trochanteric fractures has a favorable prognosis. Skeletal traction (6–8 weeks) is applicable in young patients. However, for the elderly, prolonged bed rest is fatal due to the risk of hypostatic pneumonia, pressure ulcers, and thromboembolism. Therefore, the standard of care is surgical fixation using dynamic hip screws (DHS) or intramedullary nails (PFN/PFNa) with mandatory early mobilization.
Treatment of femoral neck fractures (transcervical and subcapital) is significantly more complex. Conservative management (positional immobilization and unloading) is allowed only for impacted injuries with a horizontal fracture line (Pauwels group I). Non-impacted fractures require surgery, as bone union virtually never occurs without it. Closed osteosynthesis is performed in young patients. In debilitated elderly patients, as well as in cases of avascular (non-viable) femoral head, primary joint arthroplasty is the method of choice. This allows full weight-bearing on the leg just a few days after surgery.
Briefly: answers to topical questions
Which specific arteries supply blood to the femoral head and neck?
The femoral head and neck are supplied predominantly by two circumflex arteries and their branches.
- Medial circumflex femoral artery (a. circumflexa femoris medialis) — runs posteriorly, forming an extracapsular vascular ring at the base of the neck.
- Lateral circumflex femoral artery (a. circumflexa femoris lateralis) — runs anteriorly, participating in the formation of the same ring.
- Ascending cervical arteries (ascending cervical arteries) — branch off from the vascular ring, run parallel to the neck, and nourish the femoral head.
- Femoral artery (a. femoralis) and deep femoral artery (a. profunda femoris) — sources from which the circumflex branches originate.
What types of fractures are distinguished in Pauwels' biomechanical classification depending on the angle of the fracture line?
Pauwels' classification is based on the angle between the femoral neck fracture plane and the horizontal, determining the tendency toward "disimpaction".
- Group III — vertical valgus fracture, has the greatest tendency to "disimpaction", surgical treatment (closed osteosynthesis) is indicated.
- Group II — the angle of the fracture plane to the horizontal is 30–50°, has a lesser tendency to "disimpaction".
The description of Group I and the exact numerical limits of the angle for Group III are absent in the sources.
What stages of fragment displacement are distinguished in Garden's classification of femoral neck fractures?
Garden's classification distinguishes four types (stages) of femoral neck fracture depending on the degree of fragment displacement.
- Type I (Stage 1) — incomplete non-displaced fracture, including an impacted fracture with valgus deformity.
- Type II (Stage 2) — complete non-displaced fracture.
- Type III (Stage 3) — complete fracture with partial displacement and varus deformity.
- Type IV (Stage 4) — complete fracture with complete displacement of fragments.
What types are femoral neck fractures divided into according to the anatomical level of the fracture line?
According to the level of the fracture line, the sources list subcapital, transcervical, basicervical, and intertrochanteric fractures.
- Subcapital fracture — with displacement, the blood supply to the head is completely disrupted, the head is in avascular conditions.
- Transcervical fracture — the blood supply to the proximal fragment is partially preserved and suffers less the closer the fracture is to the base of the neck.
- Basicervical fracture — basicervical.
- Intertrochanteric fracture — a separate type indicated in the source classification.
The "stuck heel" sign is easy to picture literally: the leg is motionless, the foot is limply turned outward, and the patient is physically unable to lift the heel off the sheet — this is a classic marker of a displaced fracture.
Class and exam questions
Why get an X-ray if only the groin hurts after a fall and the leg moves?
Against the background of osteoporosis, this may be the only symptom of an impacted fracture. If missed, the patient will continue to walk, leading to severe secondary displacement of the fragments.
Why are casts not applied to elderly patients with femoral neck fractures?
A hip spica cast requires months of bed rest, which in elderly people almost inevitably leads to fatal complications (pneumonia, thromboembolism). In addition, it is unable to reliably fix fragments inside the joint.
What is the difference between absolute and relative leg shortening?
In a femoral neck fracture, the true length of the bone itself (from the joint to the condyles) does not change. However, due to a change in the neck-shaft angle (varus deformity), the entire leg functionally becomes 2–3 centimeters shorter.
What else to study on this topic
- Pauwels' classification of femoral neck fractures and its impact on the risk of displacement.
- Biomechanics of implants: the difference between DHS and PFN systems.
- Algorithm for preventing hypostatic complications in bedridden trauma patients.
- Indications and technique for arthroplasty in avascular necrosis of the femoral head.
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