Residency · Residency · Orthopedic Surgery
Femoral Shaft Fractures: Nailing and Special Situations
Overview
Femoral shaft fractures are high-energy injuries in young adults and may be low-energy in the elderly or osteoporotic population. Intramedullary nailing is the gold standard treatment. Key decision points include antegrade versus retrograde nailing, reamed versus unreamed technique, and management of special situations such as ipsilateral neck and shaft fractures, polytrauma, and obesity.
Anatomy
The femur is the longest and strongest bone in the body, with a normal anterior bow of 6 to 8 degrees and a radius of curvature of approximately 120 cm. The medullary canal narrows at the isthmus in the middle third. An extensive muscle envelope provides blood supply and soft tissue coverage but also creates deforming forces. The three muscle compartments are the anterior (quadriceps), posterior (hamstrings), and medial (adductors). The nutrient artery, a branch of the profunda femoris, enters the posterior cortex in the proximal third and supplies the inner two-thirds of cortical bone, while periosteal blood supply provides the outer one-third.
Classification
The AO/OTA system classifies femoral shaft fractures as 32A (simple), 32B (wedge), and 32C (complex or multifragmentary). The Winquist-Hansen grading system describes comminution: Grade 0 has no comminution, Grade I has a small butterfly fragment involving less than 25% of the circumference, Grade II involves 25 to 50%, Grade III exceeds 50% with limited cortical contact, and Grade IV has circumferential comminution with no inherent stability. A descriptive classification noting open versus closed, location (proximal, middle, or distal third), and fracture pattern is also used.
Initial Management
High-energy femoral shaft fractures require assessment as polytrauma under the ATLS protocol. Blood loss of 1 to 1.5 liters per fracture is expected, and more with open injuries. Temporary stabilization includes a traction splint (Thomas or Hare) in the field and emergency department, and a skeletal traction pin in the distal femur or proximal tibia if surgery is delayed. The ipsilateral knee must be examined after stabilization, as 20 to 30% of patients have associated ligamentous knee injuries.
<image>Antegrade femoral nailing showing trochanteric entry point, reaming, and final nail position with interlocking screws</image>
Surgical Treatment: Intramedullary Nailing
Antegrade Nailing
Antegrade nailing is the standard approach for most femoral shaft fractures. Patient positioning options include the fracture table in supine (the most common setup, allowing traction and fluoroscopic visualization) and the lateral decubitus position on a radiolucent table (useful for obese patients and providing easier access to the trochanteric entry point). The piriformis fossa entry is in line with the medullary canal but should be avoided in children because of the risk of AVN from injury to the MFCA. The trochanteric entry at the tip of the greater trochanter is the most commonly used modern entry point; it requires a nail with a lateral bend to accommodate the offset and carries a lower AVN risk. Technique involves guide wire insertion under fluoroscopy, sequential reaming (usually to 1.5 to 2 mm above nail diameter), nail insertion with confirmation of length and rotation, and proximal and distal interlocking screws.
Retrograde Nailing
Retrograde nailing uses an entry point at the intercondylar notch, at the anterior edge of Blumensaat line on the lateral view. Indications include distal-third fractures, bilateral femoral fractures, ipsilateral femoral neck and shaft fractures (controversial), pregnancy, obese patients with a difficult antegrade starting point, ipsilateral acetabular fractures, and floating knee injuries. Contraindications include an immature skeleton with an open distal femoral physis, active knee sepsis, and a narrow distal canal. Potential complications include knee stiffness, knee pain, and violation of the knee joint with a risk of septic arthritis. Results are equivalent to antegrade nailing for midshaft fractures.
Reamed vs. Unreamed Nailing
Reamed nailing is preferred because it allows a larger nail diameter, better cortical contact, and provides an autograft effect from the reaming debris. Unreamed nailing uses thinner nails with less disruption of endosteal blood supply and was historically advocated for open fractures and polytrauma. However, the SPRINT trial demonstrated that reamed nailing had a lower reoperation rate than unreamed, even in open fractures. Current practice favors reamed nailing for essentially all femoral shaft fractures.
Interlocking
Static locking with screws through both proximal and distal interlocking holes controls length and rotation and is required for all unstable patterns (Winquist III-IV and comminuted fractures). Simple transverse fractures may be treated with fewer locking screws. Dynamization, the removal of interlocking screws at one end to allow axial compression at the fracture site, is considered at 3 to 6 months if delayed union develops. Screws are removed from the end farther from the fracture.
Special Situations
Ipsilateral Femoral Neck and Shaft Fractures
These occur in 2 to 6% of femoral shaft fractures, and the femoral neck fracture is often missed. Dedicated hip views should be obtained in all femoral shaft fractures. The neck fracture takes priority because of the risk of AVN. Treatment options include a retrograde nail for the shaft combined with cannulated screws for the neck, an antegrade reconstruction nail with a proximal lag screw through the femoral neck, or sequential fixation addressing the neck first and then the shaft. Regardless of technique, the neck fracture should be fixed or stabilized first.
Bilateral Femoral Shaft Fractures
Bilateral fractures are associated with higher mortality and fat embolism risk. Damage control orthopedics with external fixation of one or both sides initially, followed by delayed nailing, should be considered. If the patient is stable, both can be nailed in the same sitting, and retrograde bilateral nailing avoids repositioning.
Open Femoral Shaft Fractures
Antibiotics must be administered within one hour. Surgical debridement should be performed urgently though not necessarily emergently. Reamed nailing is acceptable based on SPRINT trial data supporting it even for type I, II, and IIIA open fractures. Type IIIB and IIIC injuries may require temporary external fixation followed by delayed nailing, with soft tissue coverage within 7 days.
Femoral Shaft Fractures in the Obese Patient
Technical challenges include difficult access to the starting point for antegrade nailing and poor fluoroscopic visualization. The lateral position on a radiolucent table facilitates antegrade nailing. Retrograde nailing may be preferred in morbidly obese patients. Higher complication rates are expected, including malreduction, hardware failure, and wound complications.
Floating Knee (Ipsilateral Femur and Tibia Fractures)
The Fraser classification divides these into Type I (both diaphyseal) and Type II (one or both intra-articular). Both fractures should be treated surgically, with the femur stabilized first. A retrograde femoral nail combined with an antegrade tibial nail allows a single prep and drape. Knee ligament assessment follows fixation of both fractures.
Pathologic Femoral Shaft Fractures
A biopsy should be performed first if there is no known primary malignancy. Treatment involves a reamed locked intramedullary nail spanning the entire bone to protect against additional lesions. Cemented reconstruction may be required for extensive lytic lesions.
<image>Ipsilateral femoral neck and shaft fracture management with retrograde nail and cannulated screws</image>
Reduction Techniques and Tips
The goal of intramedullary nailing is not anatomic reduction but restoration of length, alignment, and rotation. Acceptable alignment parameters are less than 5 degrees of varus or valgus, less than 10 degrees of flexion or extension, less than 10 degrees of rotation, and less than 1 cm of shortening. Rotation is assessed by comparing the lesser trochanter profile to the contralateral side and matching cortical diameter above and below the fracture. Blocking (Poller) screws are placed in the medullary canal adjacent to the nail to redirect it and correct coronal or sagittal malalignment; they are critical for metaphyseal fractures. Percutaneous reduction instruments include the ball-spike pusher, F-tool, and Schanz pin used as a joystick. The fracture table with traction is effective but carries a risk of pudendal nerve palsy from the perineal post, so traction time should be limited.
Complications
Fat Embolism Syndrome
Fat embolism syndrome presents with the classic triad of respiratory distress, neurologic changes, and petechial rash. It is associated with long bone fractures (especially the femur) and reaming, usually developing 24 to 72 hours after injury. Treatment is supportive, and early fracture stabilization reduces its incidence.
Malrotation
Malrotation is the most common technical error in femoral nailing. A rotational difference greater than 15 degrees from the contralateral side is clinically significant. Prevention requires careful intraoperative assessment of rotation by comparing cortical diameter above and below the fracture and evaluating the lesser trochanter profile.
Femoral Neck Fracture (Iatrogenic or Missed)
Femoral neck fractures can occur during nailing, especially with piriformis entry in proximal fractures. The femoral neck should be screened with dedicated views before and after nailing.
Hardware Failure
Nail breakage is rare with modern implants and occurs at the level of the fracture with persistent nonunion. Interlocking screw breakage may occur with dynamization or cyclic loading.
Nonunion
The nonunion rate is approximately 1 to 3% with reamed nailing. Risk factors include open fracture, smoking, infection, and comminution. Treatment options include exchange nailing with a larger reamed nail, plate augmentation with a lateral plate and nail in situ, and bone grafting.
Clinical Pearls
Always obtain dedicated hip and knee imaging in femoral shaft fractures because ipsilateral femoral neck fractures and knee ligament injuries are commonly missed. The lateral position on a radiolucent table has become increasingly popular for antegrade nailing because it provides excellent access to the starting point and avoids the complications of the fracture table, including pudendal nerve injury and perineal skin issues. Rotational malunion is the most common complication of femoral nailing, and time should be taken to assess rotation before final locking. Blocking screws are underutilized but dramatically improve reduction quality, especially in proximal and distal third fractures. Early stabilization of femoral shaft fractures in polytrauma within 24 hours reduces pulmonary complications and ICU length of stay, though damage control principles apply when the patient is physiologically unstable.
References
- Winquist RA, Hansen ST. Comminuted fractures of the femoral shaft treated by intramedullary nailing. Orthop Clin North Am. 1980;11(3):633-648.
- SPRINT Investigators. Randomized trial of reamed and unreamed intramedullary nailing of tibial shaft fractures. JBJS Am. 2008;90(12):2567-2578.
- Ricci WM, et al. Retrograde versus antegrade nailing of femoral shaft fractures. J Orthop Trauma. 2001;15(3):161-169.
- Tornetta P, Kain MS, Creevy WR. Diagnosis of femoral neck fractures in patients with a femoral shaft fracture. J Bone Joint Surg Am. 2007;89(1):39-43.
- Krettek C, et al. The use of Poller screws as blocking screws in stabilising tibial fractures treated with small diameter intramedullary nails. J Bone Joint Surg Br. 1999;81(6):963-968.
