Overview
Internal fixation is appropriate for most trochanteric fractures, and the choice of implant depends on fracture stability (Campbell). These fractures occur in well-vascularized metaphyseal bone and do not threaten the blood supply of the femoral head; the aim of surgery is early weight bearing and rehabilitation (AO). Nonoperative treatment is rare and is mostly part of a palliative pathway; only isolated greater trochanter fractures are treated with mobilization and early radiographic follow-up (Rockwood).
The sliding hip screw (SHS, also called dynamic or compression hip screw) allows controlled secondary impaction along the screw axis in osteoporotic bone without joint penetration (AO).
Classification (AO/OTA 31A)
Type | Description | Stability |
|---|---|---|
31A1 | Simple two-part pertrochanteric fracture with good medial cortical support | Stable after anatomic reduction |
31A2 | Multifragmentary pertrochanteric; the lesser trochanter (and often coronal greater trochanter fragments) form separate parts | Less stable; most common type |
31A3 | Reverse oblique or transverse line from the lesser trochanter to the lateral cortex; lateral wall incompetent | Unstable |
If the fracture center lies distal to the lower edge of the lesser trochanter, it is classified as a proximal diaphyseal fracture (32A) (AO).
Features of Instability (AO)
Posteromedial comminution (risk of collapse into varus)
Extension into the subtrochanteric region
Lateral wall comminution (no support for the proximal neck fragment)
Reverse oblique fractures (medial displacement of the shaft)
Indications and Implant Choice
SHS is the implant of choice for stable 31A1 fractures (AO; Rockwood), and for many 31A2 fractures, particularly in patients with lower preinjury function (Campbell).
Evidence:
Cochrane: intramedullary fixation has not been shown to be superior to SHS for 31A1/A2 fractures, and revision rates were higher with nails (AO).
Norwegian Hip Fracture Register (17,341 patients): reoperation rates were equal for A1 fractures; for unstable A2/A3 fractures, reoperation was lower with cephalomedullary nails, with better patient-reported outcomes and lower 1-year mortality across all types (Rockwood). A US propensity-matched study (17,000 patients) found no difference (Rockwood).
Rockwood authors' preference (algorithm): A two-hole SHS is sufficient for stable A1 fractures. For A2 fractures they prefer a cephalomedullary nail, with a four-hole (or longer) SHS as second choice. For A3 and oblique fractures, a cephalomedullary nail.
Be cautious with patterns more complex than A2.1, and assess the lateral wall (Campbell).
Reverse oblique (31A3): Intramedullary nails give better results. If an SHS is used, it must be supported by a trochanteric stabilizing plate (AO; Rockwood).
Arthroplasty is not recommended as primary treatment; it may be considered in the rare patient with significant symptomatic arthritis (Rockwood).
Preoperative Planning
Imaging: Standard AP pelvis and lateral hip views. Look specifically for undisplaced lines in the lateral femoral cortex and coronal splits, which can turn an apparently simple fracture into a complex one (AO).
Occult fracture: If radiographs are negative in an elderly patient with hip pain and inability to bear weight, MRI is preferred over CT (AO).
Timing: Operate as soon as the patient is medically optimized; elderly patients deteriorate the longer they wait (AO).
Plate angle: 130° or 135° is optimal. A lower angle risks jamming of the sliding screw (making it static and increasing cut-out); a higher angle places the screw too high (Rockwood).
Surgical Technique
Positioning and Reduction
Fracture table with a perineal post. Scissor the uninjured leg or use a well-leg holder (Campbell).
Reduction: Usually traction and internal rotation (Campbell; AO; Rockwood). The typical sagittal deformity, posterior sag, may need an anteriorly directed force on the distal fragment before traction and rotation are completed (Campbell).
Injured hip in 20–30° of flexion. Place the C-arm on the contralateral side or between the legs and confirm adequate imaging before starting (Campbell).
Reduction targets (Rockwood):
AP view: Anatomic or, ideally, slight valgus. Valgus reduction is associated with the lowest cut-out rate and less shortening. A small medial gap from the valgus distraction closes quickly with collapse. Never fix the fracture in varus.
Garden alignment index: 170° is ideal for a displaced trochanteric fracture; 160°–175° is acceptable. On the lateral view, aim for 180°.
Lateral view: Head, neck, trochanteric region and shaft should form a straight line. Correct posterior sag or translation before fixation.
Rotation: Keep the patella facing the ceiling; proximal fractures usually need a little internal rotation, more distal ones a little external rotation.
If sag persists (Rockwood): Use a posterior reduction aid attached to the fracture table, an improvised vertical support (such as a crutch) under the fracture, or a bone lever or clamp to lift the femur. Percutaneous levers or probes may help, especially in reverse oblique patterns.
Avoid the common malreductions: varus, posterior sag, and excessive internal rotation (particularly when the greater trochanter is detached from the distal fragment) (Campbell).
High-energy fractures and young patients: Standard maneuvers are unlikely to work; lateral displacement often exceeds 100%, and limited or formal open reduction is usually the first step (Campbell; Rockwood). Cerclage wire can occasionally maintain reduction after open reduction (Rockwood).
Exposure
Lateral incision of 5–7 cm starting just distal to the greater trochanter (Rockwood) or at the vastus ridge (Campbell). Divide the fascia lata.
Two options for reaching the femur:
Split the vastus lateralis, or
Posterior approach: Elevate the vastus lateralis anteriorly off the lateral intermuscular septum, coagulating perforating vessels from the profunda femoris (Campbell). This is faster, damages the muscle less, and the muscle falls back over the plate (Rockwood). A small part of the tendinous insertion may need release proximally (Rockwood).
Guide Pin and Lag Screw
Insert the guide pin through the angled guide (Campbell; Rockwood).
Position: center–center (AO; Campbell) or inferior-to-center on the AP view and central on the lateral view (Rockwood). All clinical studies support inferocentral (AP) and central (lateral) placement; peripheral placement is never acceptable (Rockwood).
A pin along the anterior femoral neck helps estimate anteversion (Campbell).
A "marking" wire just above the planned position, or a 3.2 mm drill hole in the lateral cortex followed by hand insertion of the final wire on a T-handle, helps achieve optimal position (Rockwood).
Leave the wire tip about 5 mm from the joint line (Campbell; Rockwood).
Tip–apex distance (TAD): Sum of the tip-to-apex distances on AP and lateral views, corrected for magnification. Keep it at 25 mm or less; cut-out risk rises exponentially above this (Campbell; AO; Rockwood).
Quick check: The TAD should be about twice the lag screw diameter (about 8 mm) (Rockwood).
Calcar-referenced TAD: Measured from where a line parallel to the neck and touching the calcar meets the joint (Rockwood).
With helical blades, medial migration has been reported at TADs below 20 mm, and failure rates appear higher (OR 1.88) (Campbell). Clinical studies comparing cancellous screws and helical blades found them equally effective (Rockwood).
Reaming: Set the triple reamer to the measured length minus 5 mm. Do not drive the guide pin into the pelvis. Tap in good-quality bone (Campbell); tapping also reduces rotational forces on the head (Rockwood).
Lag screw length: Tip about 5 mm from the joint line; a screw left farther from the joint increases cut-out (Rockwood). Choose a screw equal to the reamer measurement, or 5 mm shorter if significant shortening is expected, but never more than 5 mm shorter (Campbell).
The lateral end of the screw should sit within the barrel, about 5 mm from its lateral end, so that early sliding occurs within the barrel and the screw does not irritate the soft tissues (Rockwood).
If the lag screw is 80 mm or less, consider a short-barrel plate to keep enough sliding capacity (standard barrel ≈ 38 mm) (Rockwood).
Prevent rotation of the head while inserting the screw, especially in comminuted and basicervical fractures: hold a finger on the anterior neck, tap first, or place an antirotation screw or wire across the fracture (Rockwood; AO). About 180° of rotation advances the screw 1.5 mm (Campbell).
At the end, align the wrench handle with the femoral axis (per manufacturer) so the plate seats correctly (Campbell).
Side Plate
Slide the plate onto the lag screw and seat it with a tamp; remove the retaining rod, wrench and guide pin (Campbell).
Secure the plate with a clamp or screw. Four-hole plates are most commonly used, although there is evidence that shorter plates can be used (Rockwood); Campbell uses two or three bicortical screws through a two- to four-hole plate.
Before fixing the plate, palpate the anterior fracture line to confirm that rotation of the proximal fragment is anatomic (Rockwood).
Compression: Release traction and insert a compression screw if desired. Clinical benefit has not been shown; weight bearing with a dynamic implant compresses the fracture anyway (Rockwood).
Closure: Let the elevated vastus lateralis fall back (no suture needed); repair it if it was split. Close the fascia lata and skin (Rockwood).
Lateral Wall Integrity
Lateral wall loss allows the shaft to medialize under adductor pull, reducing bone contact, delaying healing and reducing offset (Rockwood).
In one series, a fractured lateral wall (A3, or iatrogenic in A1/A2) led to reoperation within 6 months in 22% of patients; 74% of lateral wall fractures occurred intraoperatively. Intraoperative lateral wall fracture occurred in 3% of A1.1–A2.1 vs 31% of A2.2–A2.3 fractures (Campbell).
If iatrogenic lateral wall comminution is recognized, add a trochanteric stabilizing plate or switch to an intramedullary nail (Campbell; Rockwood).
Lateral wall thickness: Measured from a point 3 cm below the innominate tubercle, angled 135° upward to the fracture line. Less than 21 mm predicted lateral wall fracture (95% sensitivity, 88.2% specificity) (Campbell).
Modifications of the standard SHS (trochanteric side plates, percutaneous compression plates) have not shown a clear clinical advantage (Rockwood).
Postoperative Care
Mobilize on the first postoperative day, with full weight bearing as tolerated in the elderly (Campbell; AO); the fixation must allow this, because most elderly patients cannot manage partial weight bearing (AO).
Transfer to a pressure-relieving mattress as soon as possible (Rockwood).
Healing should be complete within about 3 months (AO).
All fragility fracture patients need secondary prevention (AO).
Complications
Cut-out of the lag screw, usually from varus reduction, peripheral screw position or a high TAD (AO; Rockwood).
Excessive sliding and medialization with lateral wall failure (Rockwood).
Plate pull-off from the distal fragment if full sliding occurs before union with a well-placed screw (Rockwood).
Shortening and malunion (Campbell).
References
Weinlein JC. Fractures and dislocations of the hip. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Philadelphia: Elsevier; 2026. Chapter 60, Technique 60.4.
Simmermacher RKJ. Femur, proximal. In: Buckley RE, Moran CG, Apivatthakakul T, eds. AO Principles of Fracture Management. 3rd ed. Stuttgart: Thieme; 2017. Chapter 6.6.1. (Turkish edition: AO Kırık Tedavisinin Prensipleri.)
Heetveld MJ, Flikweert ER. Trochanteric hip fractures. In: Tornetta P III, Ricci WM, Ostrum RF, McKee MD, Ollivere BJ, de Ridder VA, eds. Rockwood and Green's Fractures in Adults. 10th ed. Philadelphia: Wolters Kluwer; 2024. Chapter 54. (Turkish edition: Erişkin Kırıkları.)