Intertrochanteric Fractures

Intertrochanteric fractures are extremely common, about 50% of all hip fractures, and a major public health burden: roughly 1.6 million hip fractures a year worldwide, rising with population ageing. Unlike femoral neck fractures they are extracapsular, and the questions the exam asks are about stability assessment and implant selection.

Who. Mean age is over 80, women outnumber men 3:1, osteoporosis is the primary risk factor and a fall from standing is the most common mechanism. The distribution is bimodal:

• Elderly (90%) - low-energy falls in osteoporotic bone
• Young (10%) - high-energy trauma (motor vehicle accident, fall from height)

Why it matters. The mortality that follows is related to frailty rather than to the surgery, the risk of a second hip fracture is elevated, and the figures for survival, function and independence afterwards are set out under Outcomes and Prognosis.

The region. The fracture runs between the greater and lesser trochanters. The structures around it are the landmarks of stability:

Why extracapsular matters. The capsule inserts on the intertrochanteric line, so the fracture lies outside it and the blood supply from the medial femoral circumflex artery is not disrupted. AVN is extremely rare and union rates exceed 95%.

Loading. The hip joint reaction force is 2.5-3 times body weight in walking and puts a bending moment on the proximal femur: compression on the medial side, which the calcar resists, and tension on the lateral side, which is why the lateral wall matters.

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What decides stability. The posteromedial cortex is the key indicator: it is the calcar buttress that resists varus and shortening, and its comminution or loss marks an unstable pattern. The lesser trochanter is its marker, since a separate lesser trochanter fragment means the medial buttress has gone. Reverse obliquity is unstable in its own right. Lateral wall thickness is a different kind of measure: a wall under 20.5mm predicts the wall breaking after a sliding hip screw (Hsu), so it selects the implant rather than grading the fracture.

Load-sharing versus load-bearing. A sliding hip screw is a load-sharing device. It needs an intact medial buttress to share the load with, allows controlled collapse as the fracture heals, and fails if there is no medial support. A cephalomedullary nail is load-bearing: it carries the load independent of cortical integrity, so it works even with comminution.

Evans/Jensen and AO/OTA describe the same axis. The question behind both is whether the fracture can be anatomically reduced and provide a stable medial buttress; if it cannot (comminution, loss of the lesser trochanter, reverse obliquity) it is unstable and needs a nail.

The lateral wall. Measured on the AP radiograph as a horizontal line 3cm below the innominate tubercle to the lateral cortex. Over 20.5mm the wall is adequate for a SHS; under 20.5mm use a CMN. A thin lateral wall can fracture during SHS insertion or afterwards (Hsu's series, from which the threshold comes, recorded post-operative secondary lateral wall fractures after a dynamic hip screw), and the result is loss of stability and collapse. A CMN bypasses the problem because it is a load-bearing construct. Lateral wall integrity is the key determinant of implant selection in modern practice.

History. A fall from standing in the elderly, high-energy trauma in the young; hip or groin pain and inability to weight-bear. Pre-injury function is critical for surgical planning, and the comorbidities to ask about are cardiac, respiratory and anticoagulation. The questions that change management:

• Walking aids used before the injury?
• Living situation: independent, with family, nursing home?
• Cognitive status: dementia increases mortality
• Anticoagulation: warfarin, DOACs, and whether reversal is needed

Examination. The classic deformity is a leg shortened by 2-3cm and externally rotated 30-60°, from the unopposed pull of iliopsoas (flexion, external rotation) and gluteus medius (abduction). There is tenderness over the greater trochanter, the patient cannot lift the leg and log-roll is painful. Check the distal pulses, though injury to the vessels is rare.

Radiographs. An AP pelvis, which shows both hips for comparison, and a cross-table lateral of the affected hip are the first line, and from them come the fracture pattern, the classification and the stability features. If the pattern or displacement is hard to read, a traction internal rotation view under sedation and analgesia reduces the fracture for a better look.

CT. For surgical planning in complex patterns, for assessment of posterior comminution, and where a pathological fracture is suspected.

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Preoperative work-up. The essential tests are a full blood count for baseline haemoglobin (expect 500-1500ml of occult blood loss), urea and electrolytes for renal function, an INR if on warfarin, group and hold for 2 units of red cells, and a baseline ECG. The geriatric assessment runs alongside:

• Cognitive screening: AMT, and 4AT for delirium
• Nutritional status: albumin, weight
• Medication review: anticoagulation, polypharmacy
• ASA status for anaesthetic risk

The decision. Stability chooses the implant. A stable fracture can be fixed with either device; an unstable one, a reverse oblique or a fracture with subtrochanteric extension needs a load-bearing nail. A vertical fracture line (an unstable pattern), a segmental fracture at multiple levels, revision after failed fixation and extreme osteoporosis with poor bone for screw purchase are further indications for a nail.

Stable patterns (Evans 1A/1B, AO 31-A1). A two-part fracture with a simple line, an intact posteromedial cortex, the lesser trochanter attached, standard obliquity, an intact anterior cortex without anterior comminution, and no basicervical involvement extending into the femoral neck. SHS or CMN are both acceptable. The SHS may be preferred for cost, simplicity and the absence of shaft fracture risk, provided the lateral wall is adequate (over 20.5mm); a CMN is acceptable by surgeon preference. The Cochrane review (2022) found no difference in mortality or function between SHS and CMN, in stable patterns or in any stability subgroup, but nails carried a higher rate of implant-related femoral fracture and, in stable fractures, a slightly higher reoperation rate.

Unstable patterns (Evans 2A/2B/3, AO 31-A2). A separate lesser trochanter fragment, posteromedial comminution, or a fracture in which a stable reduction cannot be achieved. A CMN is preferred: load-bearing fixation gives stability independent of the cortex while still allowing controlled collapse with healing. A thin lateral wall (under 20.5mm) also points to a nail, as an implant-choice consideration rather than a stability grade. Be clear about what the evidence does and does not show: the Cochrane review found no difference between stability subgroups, so the case for the nail in unstable patterns rests on mechanics and on pattern-specific series (Haidukewych) rather than on that review.

Reverse oblique (AO 31-A3). The fracture line runs from medial proximal to lateral distal, the opposite direction to a standard intertrochanteric fracture, and the muscle forces cause medialisation. A CMN is mandatory; the SHS has historically high failure rates here.

Subtrochanteric extension. The fracture extends below the lesser trochanter into the subtrochanteric region, a high-stress area of the femur at risk of stress concentration. A long CMN is required, extending to the supracondylar region, because a short nail creates a stress riser at its tip; bypass the stress riser by 2 cortical diameters, consider a long reconstruction nail, and be ready to use cerclage wires for the reduction. Subtrochanteric extension changes the biomechanics and requires a load-bearing implant.

PositioningSHS TechniqueCMN TechniqueTAD Measurement

Set-up. Supine on a fracture table with a well-padded perineal post, since the pudendal nerve is the structure at risk, and the contralateral leg in a lithotomy holder or extended. Traction and internal rotation reduce the fracture; confirm the reduction on AP and lateral fluoroscopy, and make sure the C-arm can reach both views, because the lateral is critical for screw placement and for measuring TAD.

Reduction goals. Anatomic reduction is ideal but not always achievable. Slight valgus of 5-10° is acceptable and reduces strain on the fixation; varus is not acceptable, because it increases the failure rate significantly, and slight valgus is preferable to a varus malreduction.

Anteromedial Cortical Support - Reduction Quality Beyond Varus/Valgus

Varus/valgus is only half of reduction quality. The other half (Chang and colleagues) is the anteromedial cortical apposition between the head-neck fragment and the femoral shaft, graded on the immediate post-reduction films as positive, neutral or negative:

• Positive medial cortical support: the medial cortex of the head-neck fragment sits superomedial to, resting on, the medial cortex of the shaft. As the fracture slides under load the cortices impact and lock, limiting further collapse; this is the desired reduction.
• Neutral (anatomic): cortices flush end-to-end; acceptable.
• Negative: the head-neck medial cortex lies medial to and unsupported by the shaft cortex. It will slide off, predicting excessive collapse, loss of reduction, varus and lag-screw cutout, and should be corrected at the time of surgery.

With a load-sharing or even a load-bearing implant, a fracture that cannot rest on its anteromedial cortex keeps sliding, so positive or at least neutral anteromedial cortical contact matters as much as TAD and valgus alignment for preventing mechanical failure. The sentence to carry: accept positive or neutral anteromedial cortical support; a negative medial buttress predicts collapse and cutout and should be re-reduced.

Surgical Steps

Step 1Incision

Lateral approach to the proximal femur. Incision centred over the greater trochanter, extending distally.

Step 2Guide Wire

Insert the guide wire through vastus lateralis into the femoral head. Target: centre-inferior position on AP and lateral. Aim for subchondral bone (5-10mm from the articular surface).

Step 3Reaming and Screw

Ream over the guide wire. Insert the appropriate length of lag screw (typically 85-100mm). Confirm position on fluoroscopy.

Step 4Side Plate

Apply the barrel plate (135° standard). Compress to the fracture site. Apply cortical screws (minimum 4).

Step 5Final Check

Confirm TAD under 25mm. Check the reduction is maintained. Test stability with gentle rotation.

Pearls and pitfalls. Compress the screw to achieve fracture contact, and do not over-ream, which lets the screw toggle. On the lateral view the screw sits centrally or slightly posterior. The failures are a superior screw position, a TAD over 25mm and a varus reduction; the numbers behind them are in the TAD tab.

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Surgical Steps

Step 1Entry Point

Trochanteric entry (tip of the greater trochanter) or piriformis entry (piriformis fossa) depending on nail design. Confirm position on AP and lateral.

Step 2Canal Preparation

Insert the guide wire, confirm it is intramedullary. Ream as needed (often unreamed in the elderly). Insert the nail under fluoroscopy.

Step 3Lag Screw/Blade

Insert the guide wire for the lag screw. Target: centre-inferior on AP and lateral. TAD under 25mm. Insert the lag screw or helical blade.

Step 4Distal Locking

Perform distal locking (static or dynamic based on fracture pattern and stability).

Step 5Final Check

Confirm TAD, reduction and rotation on fluoroscopy. Check the nail is not protruding proximally.

Choosing the entry point. A trochanteric entry, used by most modern nails, is easier, especially in the obese patient, and does less damage to the abductors. A piriformis entry is aligned with the medullary canal and has less tendency to varus, but is more difficult in the obese.

Tip-apex distance. The sum of the distances from the tip of the lag screw to the apex of the femoral head on the AP and lateral views. To calculate it:

1. Measure the distance from screw tip to femoral head apex on the AP (X₁)
2. Measure the same distance on the lateral view (X₂)
3. Multiply each by the magnification correction if available
4. TAD = X₁ + X₂

The targets. Under 25mm the cutout risk is under 1%; over 25mm it rises exponentially, to greater than 15%; over 30mm it is very high. Always confirm the TAD intraoperatively, because a TAD over 25mm is a reoperation risk.

Calcar-Referenced TAD (CalTAD) - the Refinement for Cephalomedullary Nails

Classic Baumgaertner TAD references the screw tip to the femoral-head apex and rewards a dead-central position. But the lowest-cutout screw position is centre-inferior, and a centre-inferior screw can have a slightly larger classic TAD while being ideally placed, so the calcar-referenced TAD (CalTAD) was introduced, especially for cephalomedullary nails. CalTAD measures the AP component not to the central apex but to the point where a line drawn up from the calcar (the inferior cortex of the femoral neck), parallel to the neck axis, meets the head, rewarding the protective inferior screw position rather than penalising it.

Practical use: keep both classic TAD and CalTAD under 25mm, but understand that an inferior-but-not-central screw with an acceptable CalTAD is biomechanically sound (it buttresses against the dense calcar), whereas a superior screw is dangerous no matter what the classic TAD reads. The exam-ready statement: TAD under 25mm in a centre-centre or centre-inferior position; for cephalomedullary nails, CalTAD captures the protective inferior position that classic TAD can mislabel.

External fixation. Its indications in intertrochanteric fractures are very limited: the medically unstable patient who cannot tolerate standard surgery, severe cardiac comorbidity with limited anaesthetic tolerance, active infection precluding internal fixation, and the palliative setting with limited mobility goals. It is not recommended as routine treatment, with higher complication rates and worse functional outcomes than internal fixation.

Lag screw cutout. The most common mechanical failure and the most common reason for reoperation. Of its risk factors, a TAD over 25mm is the single most important; an unstable fracture pattern and osteoporosis add to the superior screw position and varus malreduction listed above.

Medical complications. For delirium, prevention is key. Pneumonia rates rise with a delay to surgery beyond 48 hours, urinary tract infection is common and catheter-associated, and early mobilisation is essential against pressure injuries.

Weight-bearing. SHS and CMN both allow immediate full weight-bearing, so the order for stable internal fixation is weight-bear as tolerated. Restricted weight-bearing is difficult for the elderly to comply with, is associated with worse outcomes, and is not necessary with modern fixation.

Orthogeriatric care. A shared care model between orthopaedics and geriatrics, covering delirium prevention and management, medication review, multimodal analgesia and early mobilisation. It reduces length of stay and mortality, improves functional outcomes, reduces complications and is cost-effective.

Mortality. By timeframe, with the factors that drive each:

Function and independence. Between 40 and 60% return to their pre-injury walking level, 25-30% need walking aids long-term and 10-15% become non-ambulatory; outcomes are better with stable fixation and early mobilisation. 50-70% return to their previous residence, 20-30% need an increased level of care and 10-20% need nursing home placement, and cognitive status is the major predictor.

Prognostic factors. The good and the bad are largely mirror images:

• Good: pre-fracture independent mobility, a stable fracture pattern, surgery within 48 hours, normal cognitive function, younger age (relative)
• Poor: pre-existing dementia, multiple comorbidities (ASA III-IV), surgery delayed beyond 48 hours, an unstable fracture pattern, non-ambulatory before the injury

Registry benchmarks. Pooled from national hip-fracture registries (NHFD in the UK, ANZHFR in Australia and New Zealand, European audits), the 30-day mortality of 7-10% overlaps the lower end of the 30-day range in the table above, with a median hospital stay of 7-10 days, a target of 80% or more operated within 48 hours, and a reoperation rate of 3-5% at one year.

Global Epidemiology

• Worldwide burden: Hip fractures are projected to rise from roughly 1.6 million per year (2000) toward an estimated 4.5-6 million per year by 2050, driven by population ageing, with the largest absolute increases expected in Asia.
• Intertrochanteric share: Extracapsular fractures account for roughly half of all hip fractures; the proportion of unstable patterns rises with age and bone fragility.
• Demographics: Mean age in the ninth decade, female predominance approximately 3:1, the great majority following a low-energy fall in osteoporotic bone.

Side-by-Side Guideline Comparison

Registry Evidence

High- vs Limited-Resource Practice Variation