Summary Femoral head fractures are rare traumatic injuries that are usually associated with hip dislocations. Diagnosis can be made by pelvis/hip radiographs but frequently require CT scan for surgical planning. Treatment may be nonoperative or operative depending on the location of the fracture and degree of fracture displacement. Epidemiology Incidence rare seen in 12% of patients with hip dislocations increased incidence due to higher MVAs and better resuscitation Etiology Pathophysiology mechanism of injury impaction, avulsion or shear forces involved unrestrained passenger MVA (knee against dashboard) falls from height sports injury industrial accidents pathoanatomy the location and size of the fracture fragment and degree of comminution depend on the position of the hip at the time of dislocation 5-15% of posterior hip dislocations are associated with a femoral head fracture because of contact between femoral head and posterior rim of acetabulum anterior hip dislocations are associated with impaction/indentation fractures of the femoral head Associated conditions femoral neck fracture (see Pipkin Classification below) acetabular fracture (see Pipkin Classification below) sciatic nerve neuropraxia femoral head AVN ipsilateral knee ligamentous instability (knee vs dashboard) Anatomy Blood supply medial femoral circumflex artery (MFCA) main blood supply to the weightbearing portion of the femoral head MFCA originates from the profunda femoris artery to the ligamentum teres lesser blood supply (10-15%) from the obturator artery or MFCA supplies perifoveal area Classification Pipkin Classification Type I Fracture below fovea/ ligamentum (small) Does not involve the weight-bearing portion of the femoral head Type II Fracture above fovea/ ligamentum (larger) Involves the weight-bearing portion of the femoral head Type III Type I or II with an associated femoral neck fracture High incidence of AVN Type IV Type I or II with associated acetabular fx (usually posterior wall fracture) Presentation History frontal impact MVA with knee striking dashboard fall from height Symptoms localized hip pain unable to bear weight other symptoms associated with impact Physical exam inspection shortened lower limb with large acetabular wall fractures, little to no rotational asymmetry is seen posterior dislocation limb is flexed, adducted, internally rotated anterior dislocation limb is flexed, abducted, externally rotated ipsilateral knee ligamentous stability neurovascular may have signs of sciatic nerve injury Imaging Radiographs recommended views AP pelvis, hip series both pre-reduction and post-reduction judet views associated acetabular fracture inlet and outlet views associated pelvic ring injury CT scan indications post reduction to evalute for loose bodies and presence/size of fracture fragments findings femoral head fracture (size, location, comminution) plane of femoral head fracture intra-articular fragments posterior pelvic ring injury impaction acetabular fracture Treatment Nonoperative hip reduction indications acute dislocations reduce hip dislocation within 6 hours outcomes 5-40% incidence of femoral head osteonecrosis increased risk with increased time to reduction TDWB x 4-6 weeks, restrict adduction and internal rotation indications Pipkin I nondisplaced Pipkin II with < 1 mm step off no interposed fragments stable hip joint outcomes satisfactory results if <1mm step off serial radiographs required development of post-traumatic arthritis based on joint incongruity and initial cartilage damage Operative ORIF indications Pipkin II with > 1 mm step off if performing removal of loose bodies in the joint associated neck or acetabular fx (Pipkin type III and IV) polytrauma irreducible fracture-dislocation Pipkin IV treatment dictated by characteristics of acetabular fracture small posterior wall fragments can be treated nonsurgically and suprafoveal fractures can then be treated through an anterior approach outcomes outcomes mimic those of their associated injuries (hip dislocations and femoral neck fractures) high rate of AVN and catastrophic failure following ORIF of Pipkin III injuries poorer outcomes associated with use of posterior (Kocher-Langenbeck) approach use of 3.0mm cannulated screws with washers arthroplasty indications Pipkin I, II (displaced), III, and IV in older patients fractures that are significantly displaced, osteoporotic or comminuted outcomes best resereved for older patients higher dislocation risk than THA performed for OA arthroscopy indications removal of loose bodies outcomes dependent on ability to remove incarcerated fragments and initial cartilage damage Techniques hip reduction technique adequate sedation and muscular relaxation are vital traction in-line with the thigh, extremity slightly adducted, counterforce on pelvis forceful reduction should be avoided obtain post reduction CT TDWB x 4-6 weeks, restrict adduction and internal rotation technique perform serial radiographs to document maintained reduction ORIF of femoral head (Pipkin I, II, III) approach anterior (Smith-Peterson) approach utilizes internervous plane between the superior gluteal and femoral nerves improved visualization reduced surgical time improved fracture reduction femoral head fracture is commonly anteromedial lower incidence of AVN less blood loss higher rate of functionally significant HO compared to posterior approach anterolateral (Watson-Jones) utilizes intermuscular plane between the tensor fascia lata and gluteus medius (both superior gluteal nerve) surgical hip dislocation with trochanteric flip osteotomy allows for complete exposure of femoral head and acetabulum similar functional outcomes to other approaches higher rates of HO compared to non-osteotomy-based approaches lower rates of subsequent AVN and post-traumatic osteoarthritis compared to alternative approaches exposure periacetabular capsulotomy to preserve blood supply to femoral head fixation two or more 2.7mm or 3.5mm lag screws countersink the heads of the screws to avoid screw head prominence headless compression screws bioabsorbable screws postop rehabilitation mobilization immediate early range of motion weightbearing delay weight bearing for 6-8 weeks stress strengthening of the quadriceps and abductors radiographs radiographs after 6 months to evaluate for AVN and osteoarthritis ORIF of femoral head and acetabulum (Pipkin IV) approach posterior (Kocher-Langenbeck) approach with digastric osteotomy trochanteric osteotomy allows access to both the femoral head fracture and posterior wall acetabular fracture preserves the medial circumflex artery supply to the femoral head utilizes plane created by splitting of gluteus maximus (no true internervous plane) anterior (Smith-Peterson) approach for fixation of suprafoveal fractures small posterior wall fractures may not need to be addressed surgically Arthroplasty approach can use any hip approach for arthroplasty posterior (Kocher-Langenbeck) approach provides the best visualization of acetabular posterior wall fracture pros & cons allows immediate postoperative mobilization and weightbearing hemiarthroplasty can be utilized if no acetabular fracture present Complications Heterotopic ossification overall incidence is 6-64% anterior approach has increased heterotopic ossification compared with posterior approach treatment administer radiation therapy if there is concern for HO especially if there is an associated head injury AVN incidence is 0-23% risk is greater with delayed reduction of dislocated hip anterior approach not associated with increased AVN risk Sciatic nerve neuropraxia incidence is 10-23% usually peroneal division of sciatic nerve spontaneous recovery of function in 60-70% DJD incidence 8-75% due to joint incongruity or initial cartilage damage Decreased internal rotation may not be clinically problematic or cause disability