Femoral head fractures

Trauma

Femoral Head Fractures

M. F. Swiontkowski

Introduction The first recognition of femoral head fracture as a separate entity was published in 1869 by Birkett.’ From the outset. it was recognised that these were high energy injuries. It is generally agreed upon that the mechanism of injury is an axial load projected through the thigh, and directed posteriorly.’ If the femoral shaft does not fracture, a hip injury will result, if sufficient force is present. If the thigh is abducted, a femoral neck fracture may result; if neutral or adducted. a posterior hip dislocation with or without an associated femoral head or posterior wall acetabular fracture will occur. This mechanism explains the increasing incidence associated with automobile accidents with loading of the thigh through the dashboard. : The final results of fracture healing, fragment resorption and/or femoral head necrosis are determined by the traumatic effect of the hip dislocation on the arterial supply of the femoral head (Fig. 1). The head is supplied by three terminal arterial sources.3 These are the artery of the ligamenturn teres from the obturator system, a terminal branch of the lateral femoral circumflex artery, and the terminal branch of the medial femoral circumflex artery, the lateral epiphyseal artery. This vessel is the critical source of the majority of the weight bearing portion of the femoral head. In 907; of hip dislocations associated with femoral head fracture, the direction is posterior. With this injury. the medial femoral circumflex artery is stretched, and the lateral epiphyseal artery may be occluded due to pressure from the edge of the disrupted _________ Marc F. Swiontkowski MD, Associate professor and Vice Chairman. chief of Orthopaedic Traumatology. Department of Orthopaedics, HarborvIew Medical Center, 325 Ninth Avenue, ?A 48, Seattle. Washington 98 104. USA

x

Anterior Fig. 1 -The

Posterior blood supply to the adult proximal femur

posterior hip capsule or acetabular labrum.s The anterior inferior femoral head fragment, which has been sheared off by the posterior wall of the acetabulum, generally remains within the acetabulum attached to the ligamenturn teres. This description relates to head fragments of significant size. When the fragment is inferior to the fovea, it may be free within the acetabulum. In larger fragments that traverse the supra-fovea1 region, the plane of the fracture most likely disrupts the osseous branches of the lateral femoral circumflex artery. The tension and/or occlusive pressure on the lateral epiphyseal artery makes prompt reduction of the femoral head within the acetabulum critical. It has been pointed out that the associated incidence of avascular necrosis of the femoral head increases with the number of hours that the hip remains dislocated.’ These concepts most certainly apply to the femoral head when there is an associated femoral head fracture.6.7 The maintenance of an optimal femoral headacetabular contact needs there to be an entire femoral head. Accurate reduction of femoral head fragments that involve the articular cartilage is necessary to

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minimise peak stresses on the articular cartilage due to step-off. The loss of a significant piece of the femoral head will cause incongruous motion. How large the femoral head piece in the anterior inferior region must be to allow the loss of this ‘shim’ effect is not known. It appears, however, that supero-lateral fragments associated with anterior hip dislocations, even of small size, will produce enough incongruity to produce rapid degenerative change.8 Treatment, therefore, should be directed at preserving the normal anatomy once the hip has been reduced.

Epidemiology Femoral head fractures, exclusively associated with hip dislocation, are the result of high energy trauma. The vast majority of the 265 reported cases are secondary to motor vehicle accidents.5-20 The mechanism in most cases associated with posterior hip dislocation is similar to that which produces femoral neck, shaft or combination fractures.2 In a series of 238 published cases, only 24 (10%) were associated with anterior hip dislocations.9 In a recently reported series of anterior hip dislocations, 15 of 22 (68%) had associated femoral head fractures.8 Because anterior dislocations occur infrequently, data on the natural history of this phenomenon are incomplete. Approximately 90% of hip dislocations are posterior. In the largest series of posterior hip dislocations, the incidence of associated femoral head fractures was 7%. 5,7 Most of the reported cases of femoral head fractures are of the shear or cleavage type. Recently the phenomenon of crush or impaction fractures has been recognised.9 The results in this last group of patients are worse than the cleavage group because of the loss of femoral head sphericity and associated noncongruent motion. These crush injuries have been primarily reported associated with anterior hip dislocations, but are now being recognised more frequently in association with acetabular fractures.8* l8 The complication of post-traumatic necrosis of the femoral head is frequently seen in association with posterior hip dislocation. While this complication accompanies 13% of posterior hip dislocations it is seen in 18% of these dislocations associated with femoral head fractures.5,6,7*14 A higher incidence is most likely due to the greater amount of force required to produce the accompanying fracture, with resultant,

Table 1-Pipkin Fracture Type 1 Type 11 Type III Type IV

Type

Classification

of Femoral

Head Fractures

Description (Hip) dislocation with fracture of the femoral head caudal to the fovea capitis femoris (Hip) dislocation with fracture of the femoral head cephalad to the fovea capitis femoris Type I or Type II injury associated with fracture of the femoral neck Type I or Type II injury associated with fracture of the acetabular rim

more severe soft tissue disruption. Delay in closed reduction may result because of the mismatched fracture surfaces or interposed fragments and soft tissue and this may be associated with the higher incidence of avascular necrosis. Optimal management of these injuries requires a prompt reduction to minimize the risk of this devastating complication in young patients.

Classification Birkett’s initial recognition of the associated nature of femoral head fractures with hip dislocation has been extended’ lq6.21 but Pipkin’s article on femoral head fractures remains the most significant work yet published on this subject (Table 1).16 This schema includes allowance for increasing severity, which is useful in terms of prognosis (Fig. 2) but there was failure to recognise the association with anterior hip dislocation. The most thorough classification of these injuries is that shown in Table 2.9 This system is significantly more detailed and does include anterior dislocation with associated fractures. It is an expansion of Pipkin’s super/infra-oveal classification and expands upon the more complicated areas of acetabular fracture and hip dislocation. It is complex and well organised and grading is related to increasing severity in most instances.

Treatment Diagnostic studies

An early report on these fractures from 1926 revealed a 47% mortality rate overall, which underlines the significant trauma associated at that time.12 Critical evaluation of the whole patient must be performed by the trauma team. The hip dislocation, if it remains unreduced, will dictate the findings on the initial examination. Posterior dislocation will leave the limb shortened, flexed, adducted and internally rotated, while the anterior obturator type of dislocation will produce a limb which is flexed, abducted and externally rotated. A quick survey of the limb position is noted, followed by a rapid assessment of the circulatory status. Sciatic and femoral nerve function should be assessed as best as possible. The ability to flex and extend the ankle and knee, while palpating muscle bellies, is generally the most practical test. A careful sensory examination of light touch and pin prick should follow and no attempt at hip reduction should be performed until the examination is completed on an awake and alert patient. An AP radiograph of the pelvis, along with the lateral cervical spine and chest X-ray is a routine part of the evaluation in the patient with multiple injuries. The hip injury will be apparent on this screening radiograph. In the assessment of a posterior hip

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Fig. Z-Pipkln’s classification of femoral head fractures; (A) Type I is an infra-fovea1 fracture, Type II is supra-foveai, (B) Type III with an associated femoral neck fracture and (C) Type IV with an associated acetabular fracture.

Table 2-~ Brumback. Fracture

of Hip Fractures

Type Descriptton -- ___

TYPO

Type

A

Type

B

Type ?

Type ?A Type 2B Type 3 Type 3.A Type 3B Type 4 7Iype 4A Type 4B

Type 5

et al’s Classtfication

A posterror hip dislocation with femoral head fracture involving the inferomedial. non-weightbearing portion of the femoral head. With minimum or no fracture of the acetabular rim and stable hip joint after reduction With significant acetabular fracture and hip joint stability A posterior hip dislocation with femoral head fracture involving the superomedial, weightbearmg portion of the femoral head. With mmimum or no fracture of the acetabular rim and stable hip joint after reduction With stgnificant acetabular fracture and hip joint mstahility Dislocation of the hip (unspecified direction) associated femoral neck fracture Wtthout fracture of the femoral head With fracture of the femoral head

with

Anterior dislocation of the hip with fracture of the femoral head Indentation type; depression of the superolateral weight-bearing surface of the femoral head franschondral type; osteocartilaginous shear fracture of the weight-bearing surface of the lemoral head C‘entral fracture-drslocation of the hip wtth fracture of the femoral head

dislocation, the X-ray must be scrutinised to see any femoral head fragment remaining in the acetabular fossa, or incomplete sphericity of the dislocated femoral head. The femoral neck region must be carefully evaluated before the decision is made to

attempt a closed reduction, in that it has been widely reported that an attempt at closed reduction of nondisplaced femoral neck fractures in this setting will produce displacement. If the radiograph demonstrates hip dislocation, with or without an associated femoral head fracture, the surgeon should proceed with closed reduction. If an associated acetabular fracture is noted, as in a Pipkin Type IV fracture. the prereduction radiographic evaluation should include the 45’ oblique views as described by Judet whenever possible if their use is not associated with prolonged (more than fifteen minutes) delays. Based on the condition of the patient and associated injuries, the decision must then be made to attempt the closed reduction under sedation in the emergency department or under general anaesthesia in the operating theater. If the attempt under adequate sedation fails, suggesting the fact that an open reduction may be required, a CT scan through the acetabulum at l-3 mm intervals should be obtained rapidly. If an open reduction then becomes necessary, the scan will indicate the need to search for loose fragments, interposed soft tissue, and/or the need to perform internal fixation of associated femoral head or acetabular fractures. The scan also gives critical information regarding the choice of surgical approach. If the closed reduction is successful in either setting, it must be confirmed by a follow-up radiograph. Followup studies should also include a pelvic CT, as descri bed above, which is for loose fragments. checked for acetabular integrity and searched for reduction status of the associated femoral head fracture. While mag-

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netic resonance imaging (MRI) is gaining popularity in the disgnosis of femoral head osteonecrosis, and may offer some prognostic information, the exact clinical implications of an abnormal femoral head MRI signal post-hip dislocation are not yet clearly defined.

Definitive management Once the appropriate disgnosis of a femoral head fracture has been made, critical decisions regarding definitive management remain. The treatment options include conservative care with or without traction, open reduction with internal fixation (including reduction of associated fractures) and prosthetic replacement. Before making general recommendations, it is important to review the literature. Nearly all of the published 265 cases of hip dislocation with associated femoral head fracture are classifiable by the Pipkin scheme. The femoral head fractures associated with anterior hip dislocation will be discussed separately, in that the Pipkin classification does not cover them. In this collection of cases there are 37 (26%) Type I, 72 (42%) Type II, 25 (15%) Type III and 36 (21%) Type IV femoral head fractures. Multiple treatment regimens were employed for each classification in each published series. While Pipkin categorised results as ‘excellent’ ‘good’, ‘serviceable’ and ‘poor’ there is no clear definition for these results and other publications have also used ill-defined functional measures of results. The evaluation of these series is further complicated by the fact that many different surgeons were involved in treating these relatively rare injuries. Of the 25 Pipkin Type I femoral head fractures, 17 were treated with closed reduction and traction. Of these, 13 had good or excellent results, two fair, one poor and two were lost to follow-up. The period of time on traction varied, but generally was from 4-6 weeks. Eight additional patients were treated with fragment excision because of non-congruent reduction, fragmentation, the inability to see the fragment or because of its small size. Two of these had excellent or good results, three fair, two poor and one was lost to follow-up. Of the 36 Pipkin II cases published with follow-up, 13 were treated with closed reduction and traction, as defined above. Eight of these patients had excellent or good results, three fair and two poor. Six were treated with closed reduction and excision of the fragment for the reasons outlined above. Four had excellent or good results, two fair and none poor. Seventeen were treated with open reduction and internal fixation, 10 with excellent to good results, three fair and four poor. The larger size of the supra-fovea1 fragment and location in the weight bearing area of the femoral head would seem to invite internal fixation. Sectioning the ligamentum teres for reduction has not seemed to result in an increase in poor results. Loss of the uniform contact of the femoral head with the acetabulum (shim effect)

that results from fragment excision, adds motivation for an attempt to be made at reduction and fixation, especially when the position of the fragment of the post-reduction CT scan reveals a non-anatomical position. Femoral head fracture associated with femoral neck fracture (Pipkin III injury) has been reported in 14 patients with adequate follow-up. Three received primary arthroplasty because of an anticipated high risk of complications. Three underwent closed reduction and traction, all leading to poor results, and one underwent closed reduction and excision with a poor result. Of the 10 who underwent open reduction and internal fixation, five had excellent to good results, two fair and three poor. In the setting of the femoral neck fracture, minimum 3-5 year follow-up is necessary because of the potential complication of posttraumatic osteonecrosis and this was not available in the majority of these patients. Of significance is the fact that five of 17 cases were situations where the femoral neck fracture was initially non-displaced or produced by the closed reduction manoeuvre. The consequences of displacement are significant and care should be taken to search carefully the pre-reduction radiograph for a femoral neck fracture. If the attempted closed reduction requires significant force and reduction cannot be achieved, the surgeon should proceed with open reduction to manoeuvre interposed soft tissue out the way. The association of an acetabular fracture with a femoral head fracture defines Pipkin’s Type IV group. Neither injury can take precedence in terms of selecting treatment plan or approach. Of the 28 Type IV femoral head fractures with associated acetabular fractures and adequate follow-up, 12 were treated with closed reduction and traction, with six excellent and good results, one fair and three poor and two lost to follow-up. Eight were treated with closed reduction and excision with no good results, three fair, three poor and two lost to follow-up. Eight were treated with open reduction and internal fixation with two excellent and good results, one fair, four poor and two lost to follow-up. These data point out the utility of the classification as these results are clearly worse than the Type I and II injuries. Additionally, no details regarding the classification of the acetabular fracture are offered and this is obviously of extreme importance in determining the final outcome. This fracture type, as with all the others, suffers from the lack of detailed reporting of the final functional results related to the treatment used. In discussion of open reduction and internal fixation of the Type I and II injuries, the issue commonly raised is that of selection of surgical approach. It has been stated that an anterior approach should be avoided because it destroys the only remaining intact blood supply to the femoral head.6 Trueta has demonstrated with injection studies that the supply to the femoral head which originates from the anterior hip capsule, is negligible. A review has been made to

__~ determine the results for injuries approached from anteriorly versus those approached posteriorly.‘” Seventeen out of 37 injuries were Pipkin Type I, nine Type II, eight Type IV and three were unclassifiable due to complexities of acetabular and/or proximal femoral injury. All but five cases were treated with open reduction internal fixation. In a matched group of anterior versus posterior approaches for internal fixation of Type I and Type II injuries, 12 were included in each group. No case of avascular necrosis occurred with an anterior approach and two occurred with a posterior approach. The incidence of functionally significant heterotopic ossification in Pipkin Type I and II fractures treated with the anterior SmithPeterson approach was 33% versus zero of 12 managed with posterior approaches. In five cases where the fracture was approached posteriorly, the surgeon was unable to visualise the fragment, unable to reduce it or, (in two cases) placed internal fixation that did not engage the fracture. The authors concluded that the anterior approach offered better visualisation and

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opportunity to fix internally the femoral head fragment while offering no increase in risk of femoral head avascular necrosis. Further study of the causes and/or treatment of the heterotopic ossification associated with the anterior approach is necessary. Anterior dislocation of the hip, associated with superior indentation or shear fracture, is a more recently identified phenomenon. It is also being more widely recognised in association with acetabular fractures. The association of supero-lateral femoral head fracture with anterior hip dislocation has been of the supero-lateral reported. L H The indentation femoral head occurs as it levers off the anterior wall of the acetabulum or possibly as it impacts against the superior margin of the obturator ring. The shear fractures probably occur as the supero-laterial femoral head impacts the anterior acetabular rim and is cleaved off. These injuries have notoriously poor results. Of the 10 published impaction-type femoral head fractures, seven had evidence of significant posttraumatic arthritis at follow-up. Of the four cleavage

Fig. 3-Management of a Type I fracture: (A) A 24-year-old male was involved in a motor vehicle accident sustaining a posterior dislocatron of his left hip. A closed reduction was attempted without success and the patient underwent an emergency open reduction with removal of loose debris from the joint. Because the reduction of the head fracture was anatomrcal (B & C) this was treated without internal fixation with resultant excellent hip function at 2 years. A posterior approach is required to reduce the hip dislocation and this makes internal fixation of the femoral head fragment, which is antero-inferior extremely difficult. A second anterior exposure would be needed for Internal fixation of a head fracture

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or shear narrowing 9% (25 of distinctly

ORTHOPAEDICS-TRAUMA

fractures, all had significant joint space at follow-up. These injuries only involved 165) of femoral head fractures and have a poor prognosis for ultimate hip function.

Future areas of investigation must include improved methods for elevating depressed areas and fixing internally the superolateral segment of the femoral head.

Fig. G-Management of a Type III femoral head fracture: (A) A 39-year-old male sustained this injury in a motor vehicle accident. (B) An emergency open reduction of the femoral neck fracture was performed through a Watson-Jones approach. The associated antero-inferior femoral head fragment was not fixed internally as this would have required further capsular stripping. Despite this management, the patient developed post-traumatic osteonecrosis (C) at 10 months post-injury and required a bipolar endoprosthesis (D). In younger patients, an internal fixation of these segmental fractures should be attempted as approximately 50% will have a good result without need for further surgery.

FEMORAL

Recommendations Based on the evaluation of the post-reduction CT scan, an isolated Pipkin Type I fracture where an excellent reduction (less than l-2 mm step-off) can be achieved should be treated by closed methods (Fig. 3). Four weeks of bed rest or light traction should be followed by touchdown weight bearing on crutches for 4 weeks. This regimen has produced excellent results in the majority of patients. If the reduction is not adequate as defined above, open reduction and internal fixation.. using well countersunk small cancellous’” or Herbert:’ screas inserted following an anterior approach is recommended. In the case of polytrauma, this program may also be indicated occasionally even after ;i good reduction so as to allow mobilisation of the p:tt;,ent. The same recommendations apply to Pipkin Type 11 fractures, but because the involvement of the superior segment of the femoral head is present only an anatomical reduction as assessed on repeated radiographic evaluations and a post-reduction CT scan should be accepted. Following the closed reduction, the patient should also be examined carefully under anesthesia for post-reduction hip instability : if unstable the adequate reduction may be lost with time. For frdcturesassociated witha femoral neck fracture (Type [II injuries) the prognosis is poor. The prognosis in terms of osteonecrosis of the femoral head is related to the degree of displacement of the femoral neck fracture. For this reason, care must be taken with the Initial closed reduction to prevent displacement of a recognised or unrecognised femoral neck fracture. The threshold to proceed with a general anaesthetic for closed reduction or an open procedure, should therefore be low with hip dislocations. In the younger, more .m emergency open reduction and active patient. mternal fixation of the associated Type I or Type II femoral head fracture, followed by screw fixation of the femoral neck fracture is preferred (Fig. 4). The decision to proceed in this manner should be considered for those who are active, physiologically young and &ho have minimally displaced femoral neck fractures In relattvely inactive patients or those with widely displaced femoral neck injuries, who are more than 60-years-old. a hi-polar endoprosthesis should be :nserted. In a patient in custodial care. a rare presentation, consideration should be given towards ;t traditional endoprosthetic replacement. Pipkin Type IV fractures must be treated in tandem with their associated acetabular fractures. The pattern of the acetabular fracture should be defined by the oblique views of iudet and d CT scan. The acetabular

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fracture pattern should dictate the surgical approach towards the femoral head fracture. The femoral head fracture should, in most cases be fixed internally to allow early motion of the hip joint.

References Hlrkett J. Traumatic dislocation of the head of the lemur c.)mplicated with its fracture. Med Chir Trans I XW: 5I : 131~

I18 I unsten R V. Klnser P. Frankel C J. Dashboard dlzlocatiol; of tile hip: d report of 20 cases of traumatic dl\loc,itron. J Benz t lint Surg ;93X; NA: 124-132 T rueta J, HarrIson M H M. the normal vascular an,itom of the t~~moral hr.id m :rdult man. J Bone Joint Surg 19’3 !B: 442 ?ll f onnolly J F Acetabular labrum entrapment ;Isoclated with a it,moral head fracture-dislocation. J Bone Iomt Surs 1474. %A 17.25 1737 I pstcln H ( ‘. Pobterlor fracture-dlslocatlc,r; ot the !II~ iong ic,rrn follow-up J Bone Jornt Surg 1974: 564 1If11 1127 I hompson V P. Epstein H c‘. TraumatIc dlsloc~tlon of the b,p ,i surbeyof 204 cases covering a perioc! of ?I bears J Bvne I->lnt Surg i951 , .??A : 746 778 1 psteln H (‘. Wiis D .4, Cozen L. Posterior trac.tur<~i~fthr hip society St LOUIS (‘ V MO+\, !986. I ‘*I II)6 B!ltler J E Pipkin type 11 fractures of the femor;~l h5xd J Bone I,ilnt Surg. 1981.63A: 1292-1796 t ilahroborti S. Miller I M. Dislocation ot’the hip ds\oclated * :th fractur-e of the femoral head. Injury 1975, ?(2i I .34- 14: i ivlhtopher F. Fractures of the head of the remur \rch Sure 1’126. I2 11149 Ill61 E?s>wdG S 1:. Johnson R. Successful conser+atl\e treatment (>’ 1 fracture dislocation of the femoral hen? a ca\c report. I Bone Jomt Surg 1979; 61A: 1244 i nstoin tl ( Posterior fracture-dlslocatlon of the ternnrnl !l:::td ;I crise report. .I Bone Joint Surg 1961 43.4. I~)79 1246 f rordon F .I Freiherg J A. Posterior dislocation o~‘the hip with .f icture <‘I‘!hc he;ld of the femur. J Bone Joint SUIT :%lc); 31 2 xi.q 86’) ot’the P:pkln jrth Am 1974: i(4): 793 798 :;orpe M. Xwlontkowski M F. Sctlrr J (i. tianser~ \ -1 ( vler;ttl\c’ nlanagement of femoral head I’Iu~turc~, : arthop ‘1 ‘.inx 1991 In Press St,wart M J Mlllivd L. W. Fracture-dlsloc~iaon o’ t:~e hip: a:~ end-result \ttidy J Bone Joint Surg l9S4. 36 \ .:I ‘. ‘42 1sngr R H. Engber W D. Clancy W Ci Expand,n~ ;!;~plic,ituv~ ior thly Herbert scaphoid xcrcv <)rt!lcv- 9X6. c / ?