Anatomy of the Hip

The femoral head sits on the femoral neck, which in turn connects to two bony prominences — the greater and lesser trochanters. The blood supply to the femoral head comes largely from vessels that run around the femoral neck; damage to these vessels in a fracture creates the risk of avascular necrosis. The pelvis is a ring-shaped structure formed by the fusion of the iliac, pubic and ischial bones.

A healthy hip allows walking, sitting, bending and climbing stairs — the fundamental movements of daily life — without pain.

Femoral Head and Neck Fractures (Intracapsular)

These lie within the joint capsule. Their most important feature is the high risk of avascular necrosis, because the blood supply to the femoral head comes through this region. The Garden classification is widely used:

• Garden I: non-displaced, valgus impacted (angulated outwards and compressed); the most stable
• Garden II: non-displaced but a complete fracture; the trabecular lines remain intact
• Garden III: partially displaced (with rotation and partial contact)
• Garden IV: completely displaced; the blood supply to the femoral head is very likely disrupted
• Pauwels classification (by fracture angle): Type I (<30°), Type II (30–50°), Type III (>50°); Pauwels III is the most unstable and carries the highest risk of non-union

Intertrochanteric Fractures

These lie outside the joint capsule, in the region between the greater and lesser trochanters. This is the most common type of hip fracture, particularly in older patients. Because the fracture is extracapsular the blood supply to the femoral head is preserved and the risk of avascular necrosis is low. The AO and Evans classifications are widely used:

• Stable (simple, two-part, with an intact posteromedial cortex): treated successfully with a dynamic hip screw (DHS) or an intramedullary nail
• Unstable (comminuted, reverse obliquity, with a posteromedial defect): an intramedullary nail is preferred; the risk of implant failure is higher
• Reverse obliquity fracture: a distinct subgroup requiring an intramedullary nail

Subtrochanteric Fractures

These lie within the 5 cm below the lesser trochanter. They are exposed to high mechanical stress and are biomechanically difficult fractures. Atypical femoral fractures (related to long-term bisphosphonate use) may occur in this region. An intramedullary nail is the gold standard for treatment.

Acetabular Fractures

These are fractures of the hip socket in the side wall of the pelvis. They usually result from high-energy injuries (dashboard injuries in road traffic accidents), although they can also occur after low-energy falls in older patients. The Letournel–Judet classification (10 patterns) is used for surgical planning. Displaced fractures require surgery; acute total hip replacement may be considered in older patients with comminuted fractures.

Pubic and Ischial Ramus Fractures

These are fractures of the slender bony struts at the front and inferomedial part of the pelvic ring (the pubic and ischial rami). They are common in older patients after low-energy falls related to osteoporosis and are generally stable. Most are treated non-operatively: a short period of bed rest, pain control and weight bearing as tolerated are sufficient. In younger patients, where they occur as part of a high-energy pelvic ring injury, surgery (pelvic fixation) may be required, although this is uncommon.

Classification by Displacement and Other Features

• Non-displaced fracture: the bone fragments have not shifted; the great majority still require surgery
• Displaced fracture: the fragments have shifted; surgery is required
• Open fracture: the skin is breached; emergency surgery is required
• Pathological fracture: a fracture occurring with minimal trauma as a result of bone cancer or metastasis
• Atypical femoral fracture: a subtrochanteric or femoral shaft fracture related to long-term bisphosphonate use
• Stress fracture: may be seen in the femoral neck as a result of repetitive loading, particularly in athletes

Symptoms

• Sudden, severe groin or hip pain: after a fall or injury, particularly worse on movement
• Inability to bear weight: unable to stand or walk on the leg
• Deformity: shortening and external rotation of the injured leg (the characteristic finding in a displaced fracture)
• Tenderness: pain that increases on palpation of the groin or greater trochanter
• Restricted movement: difficulty bending or rotating the hip
• Swelling and bruising: oedema developing around the hip (particularly in intertrochanteric fractures)
• Altered sensation or coldness: if there is nerve or vascular injury (uncommon)
• Open wound: loss of skin integrity in an open fracture
• Occult fracture: pain may be mild in some non-displaced femoral neck or pelvic fractures and weight bearing may be preserved; the diagnosis is then made on MRI

Mechanisms of Injury

• Low energy: tripping or falling on level ground (the most common mechanism, particularly in patients over 65 with osteoporosis)
• High energy: road traffic accidents (particularly dashboard injuries — typical for acetabular fractures), falls from height, motorcycle accidents
• Sports injuries (in younger patients)
• Pathological: with minimal trauma in the presence of bone metastasis or tumour
• Atypical: long-term bisphosphonate use (in the subtrochanteric region)
• Stress fracture: in soldiers or athletes who run or march repeatedly

Diagnosis

Diagnosis is based on a detailed history, physical examination and imaging. The mechanism of injury, comorbidities (osteoporosis, diabetes, cardiac and respiratory disease, dementia, smoking) and medication (bisphosphonates, corticosteroids, anticoagulants) are reviewed. Examination assesses leg length discrepancy, external rotation deformity, points of tenderness, range of motion, neurovascular status and skin integrity.

Plain radiographs are the first-line investigation; anteroposterior pelvis, lateral hip and, where required, internally rotated pelvis views are obtained. CT is required for surgical planning in complex fractures and acetabular fractures. MRI is the gold standard where a femoral neck fracture is occult on radiographs, and where a stress fracture or an occult osteoporotic fracture is suspected. A bone scan is an alternative where MRI cannot be performed.

Once a hip fracture is diagnosed, a comprehensive medical assessment (ECG, blood tests, chest radiograph) is performed routinely before surgery. Additional tests are obtained in patients undergoing joint replacement (for example urine culture, or a dental opinion in patients with dental implants).

Non-operative (Conservative) Treatment

Non-operative treatment is used only in selected patients: those at very high surgical risk who are bed-bound with a short life expectancy; some non-displaced impacted or stress fractures; and stable pubic or ischial ramus fractures.

Conservative management consists of bed rest, pain control, compression stockings and anticoagulation, and mobilisation as tolerated. Prolonged bed rest markedly increases the risk of pneumonia, urinary tract infection, pressure sores and deep vein thrombosis, so surgery is preferred in most patients.

Surgical Treatment Options

The great majority of femoral fractures require surgery. The method chosen depends on the fracture type and patient factors: a dynamic hip screw (DHS), an intramedullary hip nail (short or long proximal femoral nail), cannulated screws, hemiarthroplasty (partial hip replacement) or total hip replacement. In acetabular fractures, ORIF or acute total hip replacement may be considered. The great majority of pubic and ischial ramus fractures do not require surgery.

Advantages

The principal advantage is early mobilisation and prevention of the complications of prolonged bed rest (pneumonia, DVT, pressure sores, urinary tract infection, worsening of dementia). In older patients with a hip fracture, early surgery (within the first 24–48 hours) and standing the patient up the day after the operation markedly reduce one-year mortality.

• Anatomical reduction and rigid fixation: the fragments are restored and held stable, making bone healing easier
• Early weight bearing: with modern fixation methods and prostheses, full weight bearing is usually possible the day after surgery
• Lower mortality: the complications of bed rest are minimised
• Pain control: stable fixation markedly reduces pain
• Operative time: 30–60 minutes for cannulated screw fixation; 60–90 minutes for a DHS or intramedullary nail; 60–120 minutes for hemiarthroplasty or total hip replacement
• Hospital stay usually 3–4 days

Disadvantages

• There are surgery-specific risks: wound infection, deep infection, bleeding, anaesthetic complications, deep vein thrombosis and pulmonary embolism. Surgical risks may be higher in older patients because of comorbidities
• Avascular necrosis: may develop even after ORIF, particularly in displaced femoral neck fractures (15–30%), leading to collapse of the femoral head and the need for a prosthesis
• Non-union: 10–30% in femoral neck fractures and lower in intertrochanteric fractures; increased by smoking, diabetes, osteoporosis and inadequate fixation
• Implant failure: screw cut-out (the screw penetrating the femoral head into the joint) and plate loosening may occur in osteoporotic bone
• Acetabular erosion after hemiarthroplasty: movement of the artificial femoral head within the patient's own acetabular cartilage causes wear over time; if pain returns, revision to a total hip replacement may be required
• Risk of dislocation after total hip replacement: 1–5%; the risk is highest in the first 6 weeks and slightly greater with a posterior approach. Hip precautions are required

Why Surgery?

A hip fracture is a life-threatening event, particularly in older patients; one-year mortality is 15–20%, and this rises markedly with prolonged bed rest and is higher still in patients who do not undergo surgery. Early surgery (within the first 24–48 hours) and standing the patient up with full weight bearing the day after the operation reduce complications such as pneumonia, DVT, urinary tract infection, pressure sores and worsening of dementia.

In addition, hip fractures rarely heal well without surgery; malunion, non-union and permanent shortening are common. Surgery is therefore the standard treatment in every patient who is medically fit. In younger patients, early surgical anatomical reduction is critical to preserving the blood supply to the femoral head and restoring normal joint function.

Who is a Candidate?

Surgery is the standard treatment for all displaced femoral fractures, for most non-displaced femoral fractures, and for all patients who are fit for surgery.

• Older patients with osteoporotic femoral neck, intertrochanteric or subtrochanteric fractures
• Younger patients with traumatic femoral fractures
• All patients with an expectation of independent living; those whose comorbidities are under control
• ORIF (cannulated screws) for femoral neck fractures in young, active patients
• Hemiarthroplasty in older, lower-demand patients
• Total hip replacement in active patients with fewer comorbidities and pre-existing hip arthritis
• Non-operative treatment: only in patients at very high surgical risk who are bed-bound; and in stable, non-displaced pubic and ischial ramus fractures

Expected Outcomes

Most patients with a correctly treated hip fracture return to daily activities within 3–6 months. Approximately 75% of older patients return to independent walking; some continue to walk with a stick or frame. Bone healing takes 12–16 weeks in intertrochanteric fractures and 16–24 weeks or longer in femoral neck fractures.

Early weight bearing is possible after hemiarthroplasty and total hip replacement and functional results are generally good. In young, active patients full functional recovery is possible with anatomical reduction; however, if avascular necrosis develops, total hip replacement may be required in the long term.

Risks Specific to Non-operative Treatment

• Complications of prolonged bed rest: pneumonia, urinary tract infection, pressure sores, deep vein thrombosis, pulmonary embolism
• Marked muscle atrophy and loss of strength, with difficulty walking after healing
• Increased mortality in bed-bound patients
• Malunion and shortening of the leg
• A marked fall in quality of life and loss of the capacity for independent living

Risks Specific to Surgery — Common (Under 5%)

• Superficial wound infection (usually treated with antibiotics)
• Postoperative pain, swelling and temporary bruising
• Bleeding during surgery; a blood transfusion may occasionally be required
• Temporary restriction of movement or stiffness
• Transient symptoms related to anaesthesia such as nausea, dizziness and urinary retention
• Leg length discrepancy (uncommon and usually able to be compensated for)
• Delirium / confusion (common but temporary in the first days, particularly in older patients)

Risks Specific to Surgery — Less Common

• Deep vein thrombosis (DVT) and pulmonary embolism (PE): among the most important risks of lower limb surgery; largely prevented by anticoagulation, compression stockings and early mobilisation
• Deep infection (periprosthetic infection / osteomyelitis): 1–2%; requires revision, implant removal and prolonged antibiotics
• Nerve injury (particularly the sciatic or femoral nerve; numbness in the lateral femoral cutaneous nerve territory with an anterior approach — very rare)
• Vascular injury (very rare)
• Periprosthetic fracture: a fracture of the femur or pelvis during or after surgery
• Heterotopic ossification (bone formation in soft tissue)
• Serious anaesthetic complications

Complications Specific to Femoral Neck Fractures

• Avascular necrosis (AVN): develops when the blood supply to the femoral head is disrupted; 15–30% after ORIF for displaced fractures and under 10% for non-displaced fractures. If it develops, the femoral head collapses and total hip replacement is required
• Non-union: 10–30% in displaced femoral neck fractures; increased by smoking, diabetes, delayed surgery and inadequate fixation
• Screw cut-out: the screw penetrating the femoral head into the joint in osteoporotic bone

Complications Specific to Intertrochanteric / Subtrochanteric Fractures

• Lag screw cut-out: particularly in osteoporotic bone and with incorrect screw placement
• Femoral shaft fracture: from stress concentration at the tip of an intramedullary nail (very rare)
• Non-union and delayed union in subtrochanteric fractures
• Implant failure (breakage of a plate or screw)
• Leg shortening (particularly in comminuted fractures)

Risks Specific to Hemiarthroplasty

• Acetabular erosion (wear): because the artificial head moves within the patient's own acetabular cartilage, the cartilage and bone may wear over time; if pain returns, revision to a total hip replacement is required
• Dislocation: 1–5%; the risk is highest in the first 6 weeks and slightly greater with a posterior approach
• Long-term functional results are more limited than after total hip replacement

Risks Specific to Total Hip Replacement

• Dislocation: 1–5%; the risk is highest in the first 6 weeks
• Wear: the polyethylene liner may wear over the years
• Loosening of the acetabular or femoral component

Systemic Complications (Particularly Important in Older Patients)

• Pneumonia: related to bed rest and immobilisation
• Urinary tract infection: associated with catheter use
• Pressure sores: during prolonged bed rest
• Delirium / acute confusion: common in the first days after surgery, particularly in older patients and those with dementia
• Cardiac events (heart attack, arrhythmia): in older patients and those with pre-existing heart disease
• Nutritional problems and weight loss
• Loss of independent living (in approximately one third of previously independent patients)
• Mortality: one-year mortality is around 15%; this rises in patients who do not undergo surgery

Factors that Increase Risk

• Advanced age (particularly over 80)
• Smoking (increases the risk of wound healing problems and infection)
• Poorly controlled diabetes; osteoporosis
• Immunosuppressive therapy and rheumatological disease
• Dementia or cognitive impairment (increased risk of delirium)
• Cardiac, respiratory or renal disease; obesity
• Active or recently treated infection (dental, urinary, skin)
• Malnutrition and hypoalbuminaemia
• Delay to surgery (>48 hours) — increases mortality in older patients

Contact Your Doctor Immediately If You Have

• Sudden increase in pain or swelling
• Fever above 38 °C
• Discharge, malodour or separation of the wound
• Firm, one-sided swelling, redness or increased warmth of the leg (suspected DVT)
• Shortness of breath or chest pain (suspected pulmonary embolism)
• Numbness, tingling or loss of strength in the leg
• Sudden deformity of the hip, a feeling of dislocation, or sudden shortening or external rotation of the operated leg
• Acute confusion or hallucinations (suspected delirium)

Long-term Outcomes

With accurate diagnosis, early surgery and compliant rehabilitation, most patients with a hip fracture return to daily activities within 3–6 months. Approximately 75% of older patients return to independent walking; some continue to use a stick or frame.

One-year mortality is 15–20%; this can be reduced by early surgery (within the first 24–48 hours), early mobilisation, good pain control, nutritional support, osteoporosis treatment and fall prevention programmes, but rises in patients who do not undergo surgery. In younger patients, full functional recovery is possible with correct surgery and rehabilitation.