Intracapsular Hip Fractures

Articular Cartilage

Articular cartilage covers the proximal femoral epiphysis, which roughly involves the weight-bearing hemisphere. The cartilage reaches a maximal thickness of 4 mm in the superior-most region and tapers as it approaches the equator of the hemisphere. It thins in the region of the insertion of the ligamentum teres. At the periphery of the cartilage, the retinaculum vessels penetrate the bone. Approximately 70% of the entire articular surface of the femoral head is involved in load transfer. Damage to this surface, such as that produced by fracture of the femoral head, decreases the total surface of the femoral head available for load transfer. Accompanying increases in peak compressive forces may lead to breakdown of the articular cartilage matrix, loss of the articular seal, and the development of posttraumatic osteoarthritis. Femoral head indentation fractures are associated with acetabular fractures and anterior hip dislocations. They produce the same effects with focal crushing of cartilage matrix and loss of total contact area.

Osseous Anatomy

The adult human femoral head ranges in diameter from 40 to 60 mm and is not a perfect sphere. Out-of-round estimates are in the 1- to 1.5-mm range. This subtle asphericity is reflected on the acetabular side and was previously thought to be an important factor in prosthetic design. Accurate reduction of femoral head fragments that involve the articular cartilage is necessary to maximize contact between the femoral head and acetabulum. Reduction of femoral head fragments also minimizes peak stresses across the articular cartilage.

Maintenance of optimal femoral head–acetabular contact requires the entire femoral head. Loss of a significant piece of the femoral head would allow radial-lateral, noncongruent (shear) motion. How large the anteroinferior fragment must be to compromise this “shim” effect is not known. The short-term clinical results of resection of small fragments have been satisfactory in some series and poor in others.

Degenerative Joint Disease

Crushed, indented, or fragmented articular cartilage results in loss of function of this critical tissue. If the injury is associated with poor reduction, loss of bone stock, or excision, the mechanical environment for the remaining articular cartilage is negatively affected, thereby adding further impetus to the breakdown of cartilage matrix. If significant posterior acetabular wall bone loss is also seen, posterior hip instability adds to the deterioration in hip function. In the same manner, loss of the medial shim effect produces a poor environment for survival of the remaining intact femoral head cartilage. The result of the trauma and subsequent inferior conditions for articular cartilage is degenerative arthritis of the hip and poor hip function. Because most of these injuries occur in young adults, subsequent reconstruction becomes problematic. Total hip replacement has a higher rate of failure in the long term for this patient population. Hip arthrodesis, although effective in limiting pain and optimizing function, is not an attractive option for most patients. Malunion of the femoral head fractures can lead to pain and limited hip range of motion (ROM). Late excision or partial ostectomy of smaller femoral head fragments has been reported to have reasonable short-term results.

Avascular Necrosis

AVN is frequently reported in association with posterior hip dislocation. It accompanies 13% of posterior hip dislocations and is seen in 18% of such dislocations associated with femoral head fracture. The higher incidence may be a result of the greater amount of force required to produce the accompanying fracture, which also produces more soft tissue disruption. In addition, delay in closed reduction may occur because of the fracture surfaces or interposed fragments. Delay in closed reduction has been associated with higher rates of AVN after hip dislocation with fracture of the femoral head. Optimal management of hip dislocation is required to minimize the risk of AVN because in a young adult, this complication is a devastating problem without good options for treatment. AVN appears to be more commonly associated with posterior surgical approaches than with anterior surgical approaches.

Limited Motion (Heterotopic Ossification)

Poor functional results frequently occur after dislocation of the hip complicated by femoral head fracture. In addition to joint arthrosis and AVN of the femoral head, femoral head fracture is often associated with heterotopic ossification. Such ossification results from disruption of the joint capsule and contusion, tearing, and avulsion of the abductor musculature. Heterotopic ossification can also be associated with surgical exposure. Occasionally, a type I fracture can heal to the acetabulum, affecting hip motion.

Associated Injuries

The association of femoral head fractures with hip dislocation is strong. It is difficult to conceive how a shearing fracture of the femoral head could be produced without dislocation. However, patients can present with the hip not remaining dislocated because it spontaneously reduced. Indentation fractures frequently accompany acetabular fractures and result from “central dislocation” with impaction of the femoral head on the acetabular fragments. Management of hip dislocations can have an impact on the incidence of sciatic nerve palsy because delayed reduction of a hip dislocation results in an increasing chance of incidence and severity of sciatic neurapraxia. The axial loading mechanism described previously explains the not infrequent association of knee ligament injury, patella fractures, and femoral shaft fractures. The knee and femur must be carefully examined in patients with femoral head fractures because the force is usually transmitted through these structures.

Because these injuries are a result of high-energy trauma, injury to other body systems is frequent. Critical evaluation of the whole patient by the trauma team must be performed.

History

Most femoral head fractures occur because of high-energy trauma such as motor-vehicle accidents, pedestrian versus motor vehicle, and falls from significant height. Although the mechanism of posterior dislocation is believed to be axial loading of a flexed and adducted hip and that of anterior dislocation to be abduction, flexion, and external rotation, most patients are unable to give such detailed descriptions. Information from the emergency medical service should assist with determining the mechanism and evaluating for associated injuries.

Physical Examination

The associated hip dislocation, if it remains unreduced, determines the findings of the examination on admission. Posterior dislocation leaves the limb shortened, slightly flexed, adducted, and internally rotated. The anterior obturator type of dislocation results in the injured limb being flexed, abducted, and externally rotated. The position of the limb should be noted, and then rapid assessment of circulatory status should be performed, including pulses, capillary refill, and skin temperature. This examination must be followed by a thorough assessment of sciatic and femoral nerve function. The ability or lack thereof to dorsiflex and plantar flex the ankle, invert and evert the foot, and flex and extend the knee should be evaluated by palpating the muscle bellies as the indicated motion is attempted, followed by a careful sensory examination involving light touch. No reduction of the hip joint should be attempted until this examination is complete and documented. It is important to examine the ipsilateral extremity, especially the knee (dashboard injury). Associated bony or ligamentous injury to the ipsilateral knee or femoral shaft is not uncommon. When associated with a femoral shaft fracture, a dislocation may go unrecognized because the classic position of flexion, internal rotation, and adduction is not apparent. Dedicated radiographs will be needed if suspicious of other lower extremity injury.

Radiographic Imaging

An anterior-posterior (AP) pelvic radiograph is a routine part of the evaluation of a multi-injured patient (see Chapter 10 ). If a routine chest, abdomen, and pelvis computed tomography (CT) scan has been performed, appropriate reformatting may provide much of the initial imaging required for evaluating a femoral head fracture. For patients with an isolated injury and suspected hip dislocation, proximal femoral fracture, or pelvic fracture, an AP radiograph must be obtained because the findings on this critical radiograph would determine which other radiographic studies are needed. In the case of a posterior hip dislocation, the radiograph must be scrutinized with regard to femoral head fragments remaining in the acetabular fossa. The femoral head defect is not obvious unless the angle of the radiographic beam catches the plane of the femoral head fracture in profile. In obvious posterior hip dislocation, the AP pelvis will show a superiorly displaced femoral head, a void in the acetabular socket, and a disruption of Shenton's line compared with the opposite hip. To avoid displacement of an undisplaced femoral neck component of a Pipkin type III fracture, the femoral neck should be carefully scrutinized before any decision is made to reduce the hip. If the radiograph clearly demonstrates a hip dislocation with or without a concomitant femoral head fracture, the surgeon should proceed with a closed reduction maneuver. If the dislocation is associated with disruption of the anterior or posterior pelvic ring, pelvic inlet and outlet views should be obtained after reduction so as not to delay the reduction procedure. Similarly, if an associated acetabular fracture is suspected either on the contralateral side or as in a Pipkin type IV fracture, radiographic evaluation should include the 45-degree oblique views described by Judet and Letournel.

After obtaining the best possible plain radiographs, an attempt is usually made at closed reduction, which may be done in the emergency department with analgesia and conscious sedation or in the operating room with general anesthesia and complete muscle relaxation. Although the latter is probably less traumatic, it may not be an available option without excessive delay. Thus it is often appropriate to attempt gentle closed reduction in the emergency department. If such reduction is unsuccessful and if further studies do not delay general anesthesia, CT through the acetabulum and femoral head at 2-mm cut intervals should be rapidly performed. If open reduction becomes necessary, a CT scan will assist the surgeon in searching for loose bodies and interposed soft tissue or in performing open reduction and internal fixation (ORIF) of an associated femoral head or acetabular fracture. It additionally serves as a valuable source of information for the surgeon regarding the choice of surgical approach. A CT-directed pelvic oblique radiograph can also be of assistance in accurately determining the size of the fragment, as well as any displacement.

If closed reduction is successful in either setting, it must be confirmed by a follow-up AP pelvic radiograph. Additional Judet views can be beneficial after reduction to confirm concentric reduction and evaluate for other injuries such as acetabular, femoral head, and neck fractures. A postreduction CT scan of the involved hip should be obtained to evaluate for hip joint congruency, loose bodies, posterior wall acetabular fracture, femoral head fracture pattern, and the amount of femoral head fracture displacement.

Other Studies

In certain settings, electromyography (EMG), duplex ultrasonography (US), bone scans, and magnetic resonance imaging (MRI) may be useful as part of the postreduction evaluation. Patients with hip dislocations (especially those that remain dislocated for long periods) may have associated sciatic nerve palsy. EMG can play an important role in determining the specific areas of the nerve that are involved and the degree of involvement. This information is helpful in relating the prognosis for recovery to the patient, especially if EMGs are repeated serially. The initial study should not be obtained until 3 weeks after injury to allow accurate diagnosis. In patients suspected of having a lower extremity blood clot, duplex US is a convenient screening test for deep venous thrombosis (DVT) in the thigh and popliteal fossa. Technetium bone scanning can offer some predictive information regarding the chance of later AVN. If femoral head uptake is significantly lower than that of the contralateral normal hip as measured by quantitative scintimetry, the risk of later AVN may be as high as 80% to 90% but is dependent on multiple factors. Finally, MRI may offer some prognostic information about the risk of femoral head AVN. The exact clinical implications of an abnormal femoral head MRI signal are yet to be clearly defined, but MRI can explicitly identify bone contusion, sciatic nerve contusion, osteochondral fracture, and fractures of the acetabular rim or femoral head; however, its routine use cannot be recommended until clear cost-benefit advantages are apparent. The accuracy of MRI in identifying intraarticular fragments seems to be much lower than that of CT.

Classification

The first recognition of femoral head fracture as a unique entity was published in 1869 by Birkett. Thompson and Epstein's classification of posterior hip dislocations, published in 1951, included the classification of femoral head fracture as a separate entity ( Table 54.1 ). This classification did not include anterior hip dislocation, nor did it include fractures of both the acetabulum and femoral head.

Stewart and Milford's classification, published in 1954, did include the distinction between anterior and posterior hip dislocations. The associated fractures were classified as shown in Table 54.2 . Again, the system was limited by the inability to include fractures of the acetabulum with femoral head fractures. Additionally, classification of the acetabular component was lacking in detail. Because more conditions are clearly included, the Thompson Epstein scale was used in most publications of the 1950s and 1960s.

Pipkin's landmark article on femoral head fractures included his new classification system ( Fig. 54.3 ). This article has remained the most significant contribution to the subject and it is the most commonly used classification for femoral head fracture. The Pipkin classification is shown in Table 54.3 . This classification describes the location of the femoral head fracture and whether there is associated femoral neck or acetabular fracture. The major deficiencies of this classification are the lack of differentiation of anterior hip dislocation and insufficient expansion of the acetabular fracture categorization.

In 1987 Brumback and coworkers published the most complete classification ( Table 54.4 ). This classification takes into consideration the association of femoral head fracture with anterior hip dislocation. Although most authors have used Pipkin's classification since its publication, Brumback and coworkers’ classification is more complete and includes fractures of the femoral head reorganized with associated fractures. Although somewhat cumbersome, its precision warrants the use of this system in future publications.

Another classification of femoral head fractures has been proposed by Müller and colleagues and adopted by the Orthopaedic Trauma Association. Its alphanumeric categories separate and subcategorize split and depression injuries, as well as those associated with femoral neck fracture. For purposes of pooling published literature, this system should also be used when reporting case series or controlled trials.

Emergent Treatment

After adequate physical examination, review of the AP pelvic radiograph for location of the femoral head fracture, and evaluation of the femoral neck and acetabulum, early gentle closed reduction is recommended. Closed reduction of the hip is indicated for all hip dislocations regardless of whether an associated femoral head fracture is present. Techniques for closed reduction are outlined in Chapter 52 . Delay must be avoided to minimize the risk of posttraumatic AVN of the femoral head. If a femoral neck fracture is identified, it is probably better to forgo any attempt at closed reduction and proceed with open surgery after an urgent preoperative CT scan, if possible. Such an approach may decrease the risk of displacement of the femoral neck fracture with further injury to the vascular supply of the femoral head. Park et al. recently reported a treatment strategy to prevent an iatrogenic Pipkin type III fracture. Nine patients had an irreducible closed attempt with a clinical picture of the hip in slight, fixed flexion, neutral rotation, and shortened limb. This clinical presentation is different from other reducible hips where the limb is flexed, internally rotated, and adducted. Thus they do not recommend a repeated attempt at closed reduction for this scenario.

If closed reduction is unsuccessful in the emergency department, the patient should be taken to the operating room for a closed versus open reduction under complete muscle relaxation. A preoperative CT scan, whenever possible, helps alert the surgeon to intraarticular fragments, acetabular or femoral neck fractures, and the size of the femoral head fragment. A delay of more than an hour to obtain a CT scan should be avoided. Percutaneously placing a 5-mm Schanz pin in the proximal femur can provide better leverage than purely manual traction alone for those irreducible dislocations (see Fig. 54.4 ). If unsuccessful, an open approach should be performed. In general, posterior dislocations should be reduced through a posterior approach. The external rotators and buttonholed capsule are the usual structures blocking reduction. Intraarticular fragments can be removed with this approach and associated posterior wall acetabular fractures can be operatively reduced under direct vision. Internal fixation of the femoral neck and head, as well as reduction of these fractures, is difficult with this approach. The patient should be placed in the lateral decubitus position to allow access to the anterior aspect of the pelvis should a simultaneous approach be necessary to reduce and internally fix the femoral head fragment. A simple technique of obtaining hip distraction is using a 5-mm Schanz pin placed in the proximal femur. The 5-mm Schanz pin is placed laterally at the level of the vastus ridge. The assistant who will be distracting the hip will stand anterior to the patient. With the hip in neutral extension and the knee flexed at 60 to 90 degrees, the assistant has one arm cradled around the knee and the other hand on the T-handle chuck. The assistant can provide a significant amount of hip joint distraction to allow the surgeon to remove loose bodies and assess the femoral head. This technique allows for more freedom to externally and internally rotate the hip joint to better visualize the hip joint. Another technique is a femoral distractor applied from the iliac crest to the proximal femoral shaft, which helps gain distraction of the hip joint to improve visualization of the reduction. Without performing a surgical hip dislocation, it is difficult to attempt fixation of the femoral head, which is generally medially located. If the surgeon chooses to leave the femoral head fragment unfixed, the patient should be treated by skin or light skeletal traction for 3 to 6 weeks ( Fig. 54.5 ).

Mehta and Routt reported seven cases of irreducible fracture-dislocation of the femoral head without posterior wall acetabular fractures. The physical examination and radiographic findings in this rare injury depicted a different appearance than the standard posterior hip dislocation. The injured limb is shortened, slightly flexed at the knee and hip, and in neutral rotation. Imaging studies showed the suprafoveal femoral head fractures retained in the acetabulum while the dislocated proximal femur is locked against the lateral iliac cortical bone of the supraacetabular region. The dislocated component had buttonholed through the posterior–superior labral and capsular tissues and impacted in the acetabulum. In this series, all seven patients underwent ORIF via a Smith-Petersen surgical approach.

Special Considerations for Patients With Polytrauma

An unreduced hip dislocation is a musculoskeletal emergency because of the consequences of posttraumatic femoral head necrosis, which increases in incidence with increasing duration of the dislocation. An AP pelvic radiograph is part of the initial evaluation of a patient with multiple injuries and will reveal the hip dislocation plus the femoral head fracture. If the patient is going to the operating room for head, abdominal, or chest procedures, closed reduction of the hip dislocation can be expedited by the orthopaedist's presence after induction of anesthesia. As soon as muscle relaxation has been achieved and the airway secured, closed reduction of the hip is performed as described in Chapter 52 . If unsuccessful, open reduction should be performed as soon as other lifesaving procedures are completed. If closed reduction is successful, the same algorithm of postreduction CT followed by ORIF of a poorly reduced fracture, débridement of loose bodies, or ORIF of the femoral neck or acetabulum is used. In the case of an associated unrecognized femoral neck fracture or loose bodies, an open procedure should follow as soon as the patient can tolerate a second anesthetic. This open procedure is performed to avoid damage to the articular surfaces in the case of small loose fragments of bone or cartilage and to lower the risk of AVN of the femoral head in the case of the femoral neck fracture. Skeletal traction should be initiated in the interim when loose fragments are identified to minimize damage to the articular cartilage. Delayed operative management has been reported with good functional outcome.

In patients with well-reduced femoral head fractures of the Pipkin type I or II classification, it may be advisable to perform ORIF of the femoral head fragment to allow the patient to be mobilized. Traction, in general, should be avoided in patients with serious thoracic trauma or pulmonary dysfunction. The ability to mobilize patients with multiple injuries has been shown to have the positive benefit of reducing the incidence of pulmonary failure and sepsis.

Indications for Definitive Care

The goals of treatment for femoral head fractures are to achieve a reduction with residual displacement of 1 mm or less and a stable and congruent hip joint. For isolated Pipkin type I fracture with excellent (<1-mm step-off) reduction, closed treatment is recommended. If the reduction is not adequate, excision or fixation of the fragment is recommended. Arthroscopic assisted excision or fixation has recently been reported. ORIF with small cancellous bioabsorbable or Herbert screws is recommended, using an anterior approach. Herbert screws provide less compressive force across large cancellous surface areas than do standard small-fragment screws. In polytrauma cases, ORIF may also be indicated even when the reduction is good to allow mobilization of younger patients.

The same recommendations apply to type II fractures, but because of involvement of the superior femoral head, only an anatomic reduction on repeated radiographic evaluations should be accepted for conservative care. For cleavage femoral head fractures associated with a femoral neck fracture (Pipkin type III), the prognosis is poor. The prognosis for the injury in regard to posttraumatic AVN of the femoral head is related to the degree of displacement of the femoral neck fracture. For this reason, care must be taken during closed reduction to prevent displacement of a recognized or unrecognized femoral neck fracture ( Fig. 54.6 ). In a younger, more active patient, urgent ORIF of a type I or II femoral head fracture through an anterior Smith-Petersen approach is recommended, along with screw fixation of the femoral neck fracture. Surgical dislocation has been recently reported to provide excellent visualization of the fracture for reduction and fixation. The decision to proceed in this manner should be weighted toward treating those who are active, are physiologically young, and have minimally displaced or nondisplaced femoral neck fractures. In patients who do not fulfill these criteria, a bipolar endoprosthesis or total hip arthroplasty (THA) should be performed.

Pipkin type IV fractures must be treated in tandem with the associated acetabular fractures. The acetabular fracture should dictate the surgical approach, and the femoral head fracture, even if it is nondisplaced, should be internally fixed to allow early motion of the hip joint. Management of the associated acetabular fracture is covered in Chapter 39 .

Femoral head fractures associated with anterior hip dislocations are very difficult to manage. Elevation of the indentation fragment has been advocated, but the long-term results of this technique have not been published. The prognosis is poor because of the risk of posttraumatic arthritis, and the patient should be so informed. Cleavage fractures, if they are large and noncomminuted, may be internally fixed. The repair should be performed from an anterior approach if the CT scan indicates that the major portion of the fragment is anterior and from a posterior approach if the fragment involves the posterior, weight-bearing portion of the femoral head. No results with this treatment have been published.

Nonoperative Treatment

If closed reduction is successful, a postreduction CT scan is indicated. The scan is then reviewed for reduction of the fragment, status of the femoral neck and acetabulum, and presence of loose bodies. Treatment recommendations are then based on the classification, reduction of the fracture, and general considerations. Traditionally, skeletal traction is applied and 6 weeks of rest is recommended. However, complications such as decubitus ulcer, DVT, and pneumonia can occur with prolonged bed rest. Ideally patients who are treated nonoperatively should be allowed to mobilize with touch-toe weight bearing (TTWB) and regular repeated radiographs should be obtained to evaluate for maintenance of reduction and hip joint congruency.

Surgical Treatment

Open Reduction and Internal Fixation

ORIF is indicated for all fractures with residual displacement of 1 mm or more, for fractures associated with femoral neck or acetabular fractures, and for fractures with large femoral head fragments that require open reduction of the associated hip dislocation. For most Pipkin type I and II fractures, ORIF through an anterior Smith-Petersen approach is normally the most common ( Fig. 54.7 ). Other two common approaches are the posterior Kocher-Langenbeck approach and the surgical hip dislocation via trochanteric osteotomy. In the case of a posterior approach, without performing surgical hip dislocation, fragments off the anterior aspect of the femoral head are difficult to visualize, are harder to reduce, and can be nearly impossible to fix internally. This approach was recommended by Epstein and coworkers because of fear of damage to the blood supply to the femoral head from the anterior capsule. The blood supply to the femoral head from this source is negligible, and because of these operative difficulties, the anterior approach is favored.

Prosthetic Replacement

Prosthetic replacement is indicated in a Pipkin type III fracture when the patient is physiologically elderly or the femoral neck fracture is markedly displaced in patients older than 50 or 60 years. Primary femoral head replacement is otherwise contraindicated and should be performed only after a trial of conservative care when the result of internal fixation is joint incongruity or degenerative arthritis. Should such problems develop, total hip replacement is indicated. Details regarding the procedure of endoprosthetic replacement are discussed under the Femoral Neck Fractures section ( Fig. 54.8 ).

Surgical Approaches

Surgical Approach

A standard Kocher-Langenbeck approach is made. The interval between the piriformis tendon and gluteus minimus is identified. An electrocautery is used to mark a line at the posterior edge of the greater trochanter where the gluteus medius inserts and is extended distally on the posterior border of the vastus ridge. A wafer (1.5 cm) of bone is osteotomized off the greater trochanter in a digastric or slide fashion and the short external rotators are left intact to avoid injuring the MFCA branch. Using a fine-tooth oscillating blade (19.5 × 41 × 0.4 mm) and C-arm imaging can avoid taking too much or too little of the trochanter. Further release of the vastus lateralis distally off the proximal femur (to the level of the gluteus maximus tendon insertion) and remaining fibers of the gluteus minimus will allow the osteotomized segment to be retracted anteriorly with a Hohmann retractor. With the hip capsule exposed, a Z-shaped capsulotomy is made starting at the piriformis and the rim of the posterior acetabulum. The capsulotomy is extended from the posterior acetabulum to the anterior acetabulum and zigzags slightly posteriorly before extending down along the anterolateral femoral neck toward the lesser trochanter. Care should be taken to avoid further damage of the labrum ( Fig. 54.9 ). If there is a posterior wall acetabular fracture, a modification of the capsulotomy should be made to avoid removing the remaining capsular attachment to the wall fragment. The hip is dislocated anteriorly by pulling traction, flexing, and externally rotating the leg and putting the lower leg into the hip holder. Sometimes, carefully using a bone hook around the femoral neck or a 5-mm Schanz pin in the proximal femur may assist with dislocating the hip. The femoral head and the hip socket can be fully visualized for débridement, excision, reduction, and fixation. The femoral head is relocated with manual traction, internal rotation, and extension of the leg. Repair of the Z-shape capsulotomy is performed with nonabsorbable sutures. The greater trochanteric osteotomy is reduced and internally fixed with two 3.5-mm lag screws with or without washers ( Fig. 54.10 ).

Pearls and Pitfalls

Reduction and Fixation Techniques

• Instruments: deep retractors and nonabsorbable sutures (tag capsule) to assist with exposure, dental picks, small and large point-to-point bone reduction clamps, 1.6 and 2.0 Kirschner wires (K-wires) to reduce and key in fracture

• Implants: 2.0-, 2.4-, or 2.7-mm screws, countersink, headless compression screws

• Remove chondral debris and irrigate acetabulum

• Capsular repair with large nonabsorbable sutures

Reduction Techniques

Femoral head fragments that are very small, located caudal to the fovea, and comminuted can be excised. Placement of the 5-mm Schanz pin in the proximal femur can provide better traction than manually pulling on the leg to expose the hip joint. Using a T-handle chuck with the Schanz pin can allow for better grip for traction and rotation of the hip to allow for improved visualization of the fragment or hip joint. Femoral head fragments that are located suprafoveally or large enough to accept screw fixation should be reduced and fixed. Using a combination of small Kirschner wires (K-wires), small point-to-point reduction clamps, and dental picks, the femoral head fragments can be reduced with minimal further trauma to the articular surface.

Fixation Techniques

Interfragmentary lag screws are often used for definitive fixation of femoral head fracture. This allows for compression of the small fracture fragment and achieves rigid fixation. Multiple surgical implants are available to achieve stable fixation to allow early hip ROM. Commonly used implants are 2.0-, 2.4-, or 2.7-mm lag screws from the minifragment set. Ideally, implants are placed outside of the weight-bearing surface, but this is not always possible. Countersinking the screws will be necessary to keep the screw heads flush with the articular cartilage surface. Using the countersink before measuring with the depth gauge will allow accurate screw length measurement and allow the screw to be buried below the cartilage surface. Other implant options include headless screws (Herbert, Acutrak, and Synthes headless compression screws), bioabsorbable pins, and cannulated screws. The combination of 3-mm cannulated screws and threaded washers has been shown to do poorly in fixing femoral head fracture. The study reported that the screw backed out into the joint because of the dissociation between the threaded washer and the screw. The average physical component summary in these four patients were worse than the other patients who were treated with other implants.

Treatment of the femoral neck fracture in Pipkin type III fractures takes priority through anatomic reduction of the femoral neck through the Watson-Jones approach and ideally stabilized with three screws (cannulated or noncannulated) in an inverted triangle pattern. The femoral head fracture is assessed after fixation of the femoral neck to determine whether it can be treated through excision, fixation, or nonsurgically. Hemiarthroplasty or THA should be considered as the definitive procedure for elderly patients with Pipkin III fractures. Treatment of the acetabular posterior wall fracture in Pipkin type IV fractures can be performed via the Kocher-Langenbeck approach with or without surgical hip dislocation. The femoral head should be fixed first to obtain a congruent femoral head surface in the hip joint. Using the femoral head as the template, the acetabular posterior wall is anatomically reduced and fixed with a 3.5-mm reconstruction plate (buttress plate). It is not uncommon to have associated labral tears with a Pipkin type IV fracture. If a large labral tear is encountered, a #2 Mitek suture anchor along the acetabular rim can be used to repair the tear.

Postoperative Care and Rehabilitation

Complications

Chronic Instability.

Chronic instability is most likely to occur in the setting of fragment excision, especially when accompanied by an unreduced or excised acetabular posterior wall fragment. This complication is best avoided by internal fixation of the femoral head and acetabular fragments when they are of adequate size. When instability is recognized early, placement of a posterior wall bone graft with a tricortical iliac crest bone graft can be attempted. Chronic subluxation may result in degenerative arthritis with joint space narrowing, which requires hip arthroplasty or arthrodesis.

Wound Infection.

Wound infection can result from any operative procedure and, in general, should occur in no more than 1% of patients in whom open reduction of femoral head fragments is performed. Postoperative hip infections are usually occult, so a high index of suspicion is required. Joint aspiration is necessary for early diagnosis. Treatment of deep wound infection must be prompt and includes thorough surgical débridement of necrotic tissue, systemic administration of appropriate antibiotics, and an infectious disease consultation (see Chapter 23 ).

Heterotopic Ossification ( Fig. 54.11 ).

Heterotopic ossification may follow use of either the anterior or the posterior approach for reduction and internal fixation of femoral head fractures. In Pipkin type IV fractures in which extended surgical exposure is required to reduce and internally fix the acetabular fracture, the incidence of heterotopic ossification may be significant and is related to the approach used (see Chapter 39 ). For Pipkin types I and II fractures, the incidence of functionally significant heterotopic ossification is higher with anterior approaches. Resection of the heterotopic mass 12 to 24 months after injury, when alkaline phosphatase levels are declining toward normal and bone scan activity is decreasing, was the traditional recommendation; however, recent experience indicates this may not be necessary. Patients with posttraumatic heterotopic bone may be treated with resection and ROM therapy when they are medically stable and the bone is mature radiographically, with the caveat that the local area should not have active erythema, warmth, or swelling. Although diphosphonates play no role in prophylaxis against this complication, indomethacin, 25 mg orally three times a day, or low-dose radiation prophylaxis may be helpful. Irradiation should probably be avoided in young patients until some long-term follow-up data regarding its use are available.

Sciatic Nerve Palsy.

Sciatic nerve palsy occurs in 10% or more of posterior hip dislocations and may thus be associated with femoral head fractures. It may be more common when reduction is delayed, thus adding another reason for prompt reduction. Not infrequently, patients with sciatic nerve palsy have significant dysesthesia during the early recovery period. Should such symptoms develop, they may be helped with gabapentin, amitriptyline, carbamazepine, pregabalin, or a combination of these drugs. Serial electromyograms can yield prognostic information regarding return of function. Ankle dorsiflexion is generally the last function to return, and therefore a posterior splint or plastic ankle-foot orthosis must be used. A dense sciatic nerve palsy that follows a hip fracture-dislocation generally carries a poor prognosis for complete functional recovery.

Avascular Necrosis.

The incidence of AVN increases with the length of time that the hip remains unreduced. It is also slightly more frequent when hip dislocation is associated with femoral head fracture, probably indicative of the greater degree of trauma required to fracture the femoral head. Treatment is difficult. If the area of subchondral resorption and subsequent fracture is limited, flexion osteotomy may play a role in avoiding hip arthroplasty or arthrodesis in younger patients.

Degenerative Arthritis.

Degenerative arthritis occurs in the vast majority of cases associated with anterior hip dislocation. Similarly, it occurred in about half of the Pipkin type II, most of the Pipkin type III, and about half of the Pipkin type IV injuries reported. Oransky and associates published a long-term follow-up on 21 patients with an average follow-up of 81 months. Nearly all patients (95%) developed posttraumatic arthritis. Treatment of this complication is weight control, walking aids, and antiinflammatory medications. In physiologically older patients, treatment of severe symptoms is total hip replacement. In younger patients with manual labor professions, hip resurfacing or arthrodesis should be considered. In general, THA should be delayed as long as possible or until functional demands decrease.

Assessment of Results

A standardized system for evaluating end results is necessary to facilitate communication regarding treatment and results. Such a system is especially necessary for femoral head fractures because very few surgeons treat more than four or five of these fractures in a career. The system developed by Brumback and coworkers is the most comprehensive system used in the literature, and it is not overly complex ( Table 54.5 ). Because of the association with hip dislocation, optimal follow-up should be a minimum of 3 to 5 years to rule out posttraumatic osteonecrosis of the femoral head.

Two significant problems are evident when attempting to analyze the published series of femoral head fractures : inadequate follow-up both in the percentage of patients within the series and in duration and lack of a uniform classification. Since Pipkin's important article of 1957, most authors, including us, have attempted to use his classification. Brumback's classification is more expansive and complete but has only recently been applied to a series of published patients. This classification should be used in future publications along with the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification.

Pipkin I Conservative Versus Fragment Excision Versus ORIF

In 2011 Chen et al. reported a randomized controlled trial (RCT) evaluating conservative versus surgical fragment excision of Pipkin type I fractures. Eight patients were randomized into the conservative treatment group, which consisted of closed reduction alone and patients placed into skeletal traction for 6 weeks. The other eight patients had closed reduction and open excision of the femoral head fragment via the Smith-Petersen approach. The postoperative regimen for the surgical excision was the same as the conservative group. Patients were followed from 25 to 60 months with an average of 39 months. Using the Thompson Epstein scale and the Merle d'Aubigne and Postel score, they concluded that the function outcome of the surgical group performed better than the conservative group ( P = 0.032). Careful analysis and limitations (small series, randomization, postoperative protocol of immobilization) of this study must be considered before routinely treating Pipkin type I with surgical excision.

Park et al. reported their clinical and radiographic results on 59 patients with Pipkin type I fractures. They specifically looked at femoral head fractures that were relatively large fragment and compared excision of the fragment versus internal fixation. They concluded that early reduction and internal fixation of these Pipkin type I large fragments can have more excellent and good clinical results (Epstein criteria) and more excellent and good radiologic results as compared with fragment excision. As for Pipkin type I with small femoral head fractures, internal fixation of the fractures using hip arthroscopy has been shown to be successful.

ORIF: Anterior Versus Posterior Approaches

In a key paper published in 1989, Thorpe and associates reported 37 cases of femoral head fracture: 17 fractures were Pipkin type I, 9 were type II, 8 were type IV, and 3 were unclassifiable fractures. All but five patients were treated with ORIF, and one patient with a bilateral type IV fracture died. In evaluating anterior versus posterior approaches for internal fixation of types I and type II fractures (12 in each group), the authors concluded that the anterior approach provided superior visualization and a better opportunity to internally fix the femoral head fragment while offering no increase in the risk of femoral head AVN (two cases of AVN occurred with posterior approaches, none with anterior approaches). The incidence of functionally significant heterotopic ossification in Pipkin types I and II fractures treated with the anterior approach was 2 of 12 versus 0 of 12 posteriorly. The cause of the heterotopic bone is stripping of the gluteal muscles off the outer aspect of the iliac wing; the surgical approach now recommended involves the distal half of the Smith-Petersen approach, with the gluteal origin left intact. These results have recently been confirmed in a subsequent patient cohort.

Posterior Approach With and Without Surgical HIP Dislocation

Henle and associates and Solberg and associates reported on the outcome of femoral head fracture using the surgical hip dislocation approach (12 patients each). In the Henle et al. series, patients were followed for 2 to 96 months evaluated with the Thompson Epstein scale and the Merle d'Aubigne and Postel score. Ten patients had good to excellent results. Two patients developed AVN and required THA. Heterotopic ossification occurred in five patients. Only two were severe (Brooker III and IV) but had concomitant traumatic brain injury. Solberg et al. retrospectively reviewed 12 patients with Pipkin type IV fractures that were treated with trochanteric-flip osteotomy and surgical hip dislocation. Follow-up ranged from 24 to 71 months and outcome was documented with the Thompson Epstein scale and the Merle d'Aubigne and Postel score. Ten patients had good to excellent results. One patient developed AVN of the femoral head and four developed heterotopic ossification (three Brooker II and one Brooker III). The authors concluded that this single approach provided the surgeon good exposure and fixation for addressing both femoral head and acetabular fractures. More recently, Masse et al. in 2015 reported similar results in the largest series with 17 patients treated with surgical hip dislocation.

With regard to comparing the posterior approach with and without surgical hip dislocation, Mostafa et al. performed a retrospective review on 23 patients with displaced Pipkin types I and II. They evaluated the Kocher-Langenbeck approach in 11 patients and the surgical hip dislocation (trochanteric osteotomy) in 12 patients. There were no differences in incidence of femoral head osteonecrosis. There was a trend toward increased heterotopic ossification with the trochanteric osteotomy approach because of the excessive dissection of the abductors. The trochanteric osteotomy approach was noted to have less operative time, decrease blood loss, and better visualization for surgical fixation. However, the final outcomes (Merle d’Aubigne-Postel and Thompson Epstein scoring systems) were equally good except for one patient. They concluded that it is more important to consider the surgeon’s familiarity of the approaches, fracture type, and location when determining which approach to choose.

Meta-Analyses and Systematic Reviews

Giannoudis and associates published a systematic review on management, complications, and clinical results of femoral head fractures. There were 453 femoral head fractures with a mean follow up of 55.6 months. The majority of the femoral head fracture-dislocation causes were high-energy mechanisms. Urgent or emergent closed reduction was performed in 81.6% (275 of 337) of the cases. Successful reduction was accomplished in 84.3% (232 of 275) of the attempted closed reduction. The other cases had an emergent open reduction because of failed attempts at closed reduction or surgeon's preference to proceed with open reduction immediately. Definitive management was nonoperative in 22.9% of the cases. Common criteria for nonoperative treatment were anatomic reduction of the fracture-dislocation, no intraarticular fragment, and no instability of the hip joint. When these criteria were not met, operative treatment included excision of the fragment, ORIF, and hip replacement. The authors reported that excision of the femoral head fracture in Pipkin type I fractures had a trend for better results than ORIF, but it was not statistically significant (likely type II statistical error). For Pipkin II fractures, ORIF was recommended, with anatomic reduction and stable fixation being paramount for better outcome. There were only 26 cases of Pipkin type III fractures in this review. The recommendations were ORIF for young patients and arthroplasty for elderly patients. The results for Pipkin type IV fractures are poor and there was no consensus surgical exposure approach to these fractures. The fracture pattern and the overall injury severity characteristics play a crucial role in determining the operative approach. ORIF of the acetabulum to restore the joint congruency should be performed before ORIF of the femoral head. The surgical hip dislocation with trochanteric-flip appears to be the best option to address both fractures in Pipkin type IV fractures. The complications obtained from this systematic review were AVN (11.9%), posttraumatic arthritis (20%), and heterotopic ossification (16.8%).

Guo and associates performed a meta-analysis on 10 studies reviewing the complications of femoral head fractures and the surgical approaches. AVN rate was highest in the posterior approach (16.9%), followed by trochanteric-flip (12.5%), and the anterior approach (7.9%). However, the anterior approach had a trend toward higher incidence of heterotopic ossification (42.1%) than the other approaches. They also suggested that the trochanteric-flip appears to be the better operative approach for femoral head fractures.

In the most recent meta-analysis, Wang et al. compared the anterior approach versus the posterior approach for Pipkin types I and II. Five case-control trials were included in this meta-analysis. They concluded that the anterior approach had an increased risk of heterotopic ossification as compared with the posterior approach. There were no significant differences found for functional outcomes, osteonecrosis of the femoral head, posttraumatic arthritis, or general postoperative complications.