impacted fractures ofthe neck ofthe femur: · impacted fractures ofthe neck ofthe femur:: vol....

IMPACTED FRACTURES OF THE NECK OF THE FEMUR::

VOL. 50 B, NO. 3, AUGUST 1968 551

G. BENTLEY, OXFORD, ENGLAND

Fio,iz the Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry

Fractures of the femoral neck are considered to be impacted when they do not displace

during normal hip movement. This implies that the fragments are in close apposition so that

they move as one. They have received relatively little attention compared with displaced

fractures because they have been considered generally to be simple to treat and complicated

rarely by non-union and avascular necrosis.

Nevertheless the best method oftreatment ofimpacted fracture is still debated. Proponents

of conservative treatment point out that because most will unite under proper supervision

without internal fixation the hazards involved in operation are not justified in preventing

displacement in a small proportion of cases (Linton 1944, Crawford 1960, 1965). In addition,

internal fixation may disimpact the fracture or increase the risk of avascular necrosis of the

femoral head. Others claim that because impacted fractures often displace spontaneously in

recumbency or on early weight-bearing, and because it is impossible to predict which fractures

r ..

FIG. I FIG. 2

Figure 1-Antero-posterior radiograph of an impacted fracture of the femoral neck showingslight valgus tilt of the femoral head. Figure 2-Lateral radiograph showing slight posterior

comminution of the femoral neck.

are likely to displace, primary internal fixation is required (Banks 1962; Fielding, Wilson and

Zickel 1962; Flatmark and Lone 1962; Garden 1964). This relatively simple procedure adds

security to an already stable fracture and allows early mobilisation and weight-bearing after

operation.

in view of these divergent opinions all patients with impacted fractures of the neck of

the femur who had been treated in one group of hospitals during the last twelve years were

* This article is based on a paper read at the spring meeting of the British Orthopaedic Association held at

Southampton and Portsmouth, April 14, 1967.

552 G. BENTLEY

reviewed. The aim was to assess the overall prognosis following impacted fractures and to

examine the claims of those who favour conservative treatment and of those who favour

operation.

Criteria of impaction-The diagnosis of impacted femoral neck fracture was based on the

following clinical and radiographic features: 1) absence of deformity at the affected hip;

2) ability to rotate medially at the hip and to raise the straight leg actively; 3) painless passive

movements at the hip ; 4) radiographic appearances of a fracture of the femoral neck showing

close apposition of the fragments on the antero-posterior and lateral radiographs with a

varying degree of valgus at the fracture site (Figs. 1 and 2).

TABLE I

IMPACTED FEMORAL NECK FRACTURES. METHODS OF TREATMENT

Method of treatment � Number of fractures

Conservative . . . 47 � ,,

Operative . . . 23 Fresh 23

TABLE 11

RESULTS OF CONSERVATIVE TREATMENT FOR FRESH FRACTURES

(Forty-three cases)

� Union GMethod of treatment without d � ross�

�displacement isimpac IOfl

Rest free in bed . . . 22

Bed-rest with anti-rotation bar 14 36 7

Russell traction . . . 7

TABLE III

RESULTS OF OPERATIVE TREATMENT FOR FRESH FRACTURES

(Twenty-three cases)

Union DisimpactionMethod of treatment without -� --�displacement � Gross Slight

Smith-Petersen nail . 20

Moore’s pins . . 2 17 1 5

Chamnley screw . . I

THE PATIENTS

Seventy patients with impacted fractures of the femoral neck were studied. Forty-seven

had been treated conservatively and twenty-three by internal fixation (Table I). Twelve

patients had died during the period of the investigation. The average period of follow-up

was 25 years (six months to twelve years).

Conservative treatment. Fresh fractures-Forty-three patients with fresh im pacted femoral

neck fractures were treated in recumbency for an average period of seven weeks. The methods

employed are seen in Table 11. Twenty-two patients were treated by rest free in bed with

THE JOURNAL OF BONE AND JOINT SURGERY

2 3 4 5 6 7 8 � � 10 11 12

Yea�s ofte� injury

FIG. 3

Duration offollow-up : conservative treatment.

IMPACTED FRACTURES OF THE NECK OF THE FEMUR 553

VOL. 50 B, NO. 3, AUGUST 1968

gentle hip and knee fiexion exercises, fourteen were treated by an anti-rotational shell applied

to the lower leg, and seven were treated by light Hamilton Russell traction. Follow-up

examination was carried out after an average period of 25 years (Fig. 3).

“ 01(1 fractures-Four patients had fractures two to five weeks old when they were first

seen. They were able to walk without pain. All four were treated therefore by continued

2

.1

z

2 3 4 5 6 78

Years after injury

FIG. 4

Duration offollow-up: treatment by operation.

ambulation with protection of the limb by the use of crutches for two months. Since there

is no controversy regarding the treatment of this type of impacted fracture these four are

excluded from the comparison of methods.

Operative treatment. Fresh fractures-Twenty-three patients with fresh impacted femoral

neck fractures were treated by primary internal fixation. The methods employed in primary

internal fixation are shown in Table III. Follow-up examination took place after an average

period of 2�4 years (Fig. 4).

TABLE IV

CLINICAL ASSESSMENT OF RESULT

Excellent � Good Moderate � Poor

Pain . � None � Slight Moderate � Severe

Limp . None Slight Moderate � Marked

Movement � Full � Almost full � 50 per cent � 5��t

Sticks . � None � None or one � One or two � Two or none

Activity . Full Almost full � Indoors Slight or none

Age and sex-The average age of the patients was seventy-two years and the ratio of women

to men was 7#{149}5to 1.

Assessment-The patients were examined and the results assessed functionally as “ excellent,”

“ good,” “ moderate “ or “ poor “ on the basis of pain, limp, movement at the hip, necessity

for sticks, and activity, as shown in Table IV. Excellent and good results were considered

satisfactory and moderate or poor results unsatisfactory.

554 G. BENTLEY

RESULTS

Conservative treatment-The forty-tb ree patients treated conservatively i n recu mbency began

weight-bearing after an average period of 85 weeks. Union of the fracture without displacement

occurred in thirty-six patients (88 per cent) but gross disimpaction of the fracture occurred in

seven (16 per cent). No particular method of treatment predisposed to disimpaction. Thirty-

four patients had an excellent or good result and nine a moderate or poor result (Table V).

TABLE V

RESULTS OF CONSERVATIVE AND OPERATIVE TREATMENT

Results

Method � Patients � Weight- Union disi��ion Excellent Moderate� bearing (percentage) (percentage) or good or poor

(percentage) (percentage)

Conservative . 43 85 weeks 88 16 79 21

Internal fixation 23 3.5 weeks � 100 4 96 � 4

Operative treatment-After internal fixation in twenty-three patients weight-bearing began

after an average period of three and a halfweeks from operation. Five patients began weight-

bearing immediately after operation and nine within two weeks. Union occurred in all cases

(Table V), and in seventeen of these there was union without displacement. One fracture was

grossly disimpacted and five slightly disimpacted during internal fixation. Twenty-two patients

had an excellent or good result and one had an unsatisfactory result because of technical error.

TABLE VI

COMPLICATIONS OF CONSERVATIVE TREATMENT

Disimpaction . . . . 7

Avascular necrosis . . . 5

Pulmonary embolus . . . I

TABLE VII

DISIMPACTION DURING CONSERVATIVE TREATMENT

Disimpaction

Patients � � Timeat risk � Number of � p (weeks)

� fractures ercentage

43 7 16 Ito6

DISIMPACTION

Disimpaction during conservative treatment-Disimpaction was the only serious complication

of conservative treatment (Table VI), and the risk of its occurrence, even when the patient

is recumbent, is the main objection to non-intervention (Figs. 5 to 7). lfthe patient is confused

and restless or ifweight-bearing is allowed too soon the risk ofdisimpaction is greater. Table VII

shows that seven fractures displaced out of forty-three fresh impacted femoral neck fractures

amongst the patients treated conservatively, an incidence of 16 per cent. All seven displaced

within six weeks of the injury, the average time being three weeks.


FIG. 5



Circumstances under which disimpaction occurred-Five cases of disimpaction occurred with

the patient resting in recumbency and two on weight-bearing, at one and two weeks (Table V III).

Of the patients in whom disimpaction occurred in recumbency four were treated in hospital

and one at home. Because two fractures disimpacted from early weight-bearing and all

seven disimpactions occurred during the first six weeks after injury, it appears necessary

to keep the patient in recumbency for at least six weeks when conservative treatment is

employed. It is possible that the two cases of disimpaction from early weight-bearing and the

FIG. 6 FIG. 7

Figure 5-Impacted fracture of the femoral neck in a patient treated in recumbency with ananti-rotation shell. Figure 6-Same patient. Appearance after six weeks-commencingdisimpaction. Figure 7-Same patient. Appearance after eight weeks-gross disimpaction.

one which occurred in the patient treated at home could have been prevented by the

supervision of all patients in hospital. This would leave four inevitable cases of disimpaction.

End-results of disimpaction (Table IX)-Secondary operative treatment was advised in six out

of seven patients whose fractures became disimpacted ; one patient refused operation and

developed non-union. Two patients were treated by Smith-Petersen nailing. In the first case

reduction of the fracture was performed before internal fixation and union followed. In the

second case nailing was performed with the fracture in the displaced position and painful

non-union resulted. Replacement arthroplasty was performed in three patients with good

Number ofManagement Result

cases

Reduction and nail . . . � I Union

Nail: no reduction . . . I Non-union

Replacement arthroplasty . 3 Painfree

FIG. 8 FIG. 9

Figure 8-Impacted fracture of the femoral neck. Figure 9-Same patient-distractionof the femoral head from the neck by a Smith-Petersen nail. The nail extruded slightly

and the fracture united within five months.

556 G. BENTLEY


results. The last patient was treated by continuation of the conservative method and union

of the fracture with 45 degrees of posterior tilting of the femoral head on the neck followed.

Hence in this series, as in all others recorded in the literature, a certain proportion of impacted

fractures underwent disimpaction (Linton 1944, Flatmark and Lone 1962. Crawford 1965).

TABLE VIII

CIRCUMSTANCES IN WHICH DISIMPACTION OCCURRED

AFTER CONSERVATIVE TREATMENT

(Seven cases)

In recumbency 5 Early weight-bearing 2

In hospital 4

Athome . I

TABLE IX

END-RESULTS OF DISINIPACTI0N DURING CONSERVATIVE TREATMENT

(Seven cases)

These results suggest that approximately 10 to 15 per cent of impacted femoral neck

fractures will undergo disimpaction no matter what conservative method of treatment is

employed. For practical purposes disimpaction always requires secondary surgical treatment

to prevent non-union and consequent disability.

Disimpaction during internal fixation-The only serious complication was gross disimpaction

which occurred in one case (Table X). It is argued that internal fixation of impacted femoral

neck fractures may cause disimpaction. This may occur as the anaesthetised patient is being

positioned on the operation table or during insertion of the nail. Insertion of the nail may

IMPACTED FRACTURES OF THE NECK OF TI-IF FEMUR 557

distract the femoral head from the neck or tilt the head out of alignment with the neck into

a valgus position (Figs. 8 and 9). It is possible to avoid the first danger by positioning the

patient carefully on the operation table. Distraction or tilting of the femoral head may be

prevented by driving the guide wire into the acetabulum, thus fixing the head, before insertion

of the nail, and by counter-pressure on the opposite iliac crest during insertion.

TABLE X

COMPLICATIONS OF INTERNAL FIXATION

C I t#{149} � Number ofomp ica IOflS cases

Gross disimpaction I

Slight disimpaction � S

Nail extrusion . � 2

Avascular necrosis . � 2

Pulmonary embolus I

TABLE XI

OUTCOME AFTER DISIMPACTION DURING INTERNAL FIXATION

disin�paction � Nu��: of Management Result

Gross . � I Re-reduction and nailing . �

Nailing in valgus . . 4Slight . S Union� � Nailing with distraction I

As seen in Table Xl one fracture was grossly displaced while the patient was being

positioned on the table. This was overlooked because of the poor quality of the radiographs.

Further reduction and renailing were performed a week later. Union of this fracture occurred

after six months with posterior angulation of 60 degrees of the head on the femoral neck.

TABLE XII

TYPES OF AVASCULAR NECROSIS

After conservative treatment After internal fixation

T � Number of � T Number of:�pe cases � ype cases

Total. . � ISevere.

Superior segment � 2 Superior segment 1

Slight . Patchy necrosis . � 2 Inferior segment 1

Slight disimpaction occurred in five cases. Valgus tilting of the head on the neck occurred

in four, and uniform distraction of the head from the neck in one. Union occurred in all

five cases within five months.

Disimpaction was thus a cause of morbidity in one case only. It was due to a technical

error and should be preventable.


11 per cent

2

FIG. 11(From Garden 1964.) The extreme valgusposition in a subcapital fracture. The trabec-ulae on the medial side of the head lie at anangle greater than I 80 degrees with the medialfemoral cortex. Alignment index is I 90 degrees.

558 G. BENTLEY

THE. JOURNAL OF BONE AND JOINT SURGERY

AVASCULAR NECROSIS

Avascular necrosis is uncommon following impacted femoral neck fractures because in

most cases the displacement is insufficient to cause tearing of the retinacular vessels (Trueta

and Harrison 1953) and the vessels in the ligament of the femoral head are patent unless a

20

V 15

Q. 10

R Conseruahue treatment

Internal Fuation

0 per cent

15 per cent

Years otter njury

FIG. 10Incidence of avascular necrosis.

marked degree of valgus tilt of the femoral head is present. Hulth (1956) considered that the

cause of this necrosis was haemorrhage or effusion into the joint cavity, which may occlude

the superior retinacular vessels, especially the thin-walled veins.

Types of avascular necrosis (Table XII)-In three cases conservative treatment was followed by

the development of vascular changes involving the superior segment or the whole femoral

head with deformation ofthe head and osteoarthritic

changes. In two cases there was patchy necrosis

without arthritic change. After internal fixation

severe changes occurred in one case and slight

changes in another.

Incidence of avascular necrosis after conservative

treatment and internal fixation (Fig. 10)-None of

the patients developed avascular necrosis by one

year, but after two years 9 per cent of patients

treated conservatively and I 5 per cent of those

treated by internal fixation had developed avascular

changes in the femoral head. After three years the

figures were 14 per cent for conservative treatment

and 18 per cent for internal fixation, making an

overall incidence of 15 per cent. Only one further

case of avascular necrosis occurred later than three

years after injury. This incidence corresponds with

that found in other series. There is little difference

in the incidence of avascular necrosis after conserva-

tive treatment and after internal fixation. This

finding is in accordance with the experimental work

of Brodetti (1960) who concluded that it was unlikely

that a Smith-Petersen or similar nail placed in the

central “ neutral “ zone of the femoral head and neck would interfere with the blood supply

of the femoral head. This is especially likely in the case of impacted femoral neck fractures

in which both the retinacular vessels and the vessels of the ligament of the femoral head

are nearly always intact after injury.

FIG. 12

IMPACTED FRACTURES OF THE NECK OF TIlE FEMUR 559


Valgus position and avascular necrosis-Wolcott (1 943) and Tucker (1949) showed by injection

studies that in 70 per cent of adults the ligament of the femoral head carried one main artery

which penetrated the head of the femur and anastomosed with vessels entering via the capsule.

Smith (1959) demonstrated that the extreme valgus position of the femoral head caused

obstruction of the vessels of the ligament of the femoral head. Garden (1964) stated that

the stable but extreme valgus fracture with an alignment index greater than 180 degrees on

FIG. 13 FIG. 14

Figure 12-Impacted fracture of the femoral neck in marked valgus position. Figure 13-Samepatient-superior segment avascular necrosis after eighteen months. Figure 14-After insertion

of Austin Moore prosthesis. Symptoms were relieved.

the antero-posterior radiograph might be complicated by subsequent avascular changes

(Fig. I 1 ). In this series two of the seven patients who developed avascular necrosis had

initially a fracture in the marked valgus position. Four further patients had an alignment

index greater than I 80 degrees but the follow-up period is too short to exclude the

possibility of eventual development of avascular necrosis. Following impacted femoral neck

n�L

,;

FIG. IS FIG. 16

Figure lS--Antero-posterior radiograph of impacted fracture. Figure 16-Same fractureafter disimpaction. The fracture line now appears more vertical.

560 G. BENTLEY


fractures it is likely that the retinacular vessels are intact in many cases so that the blood

supply through the ligament of the femoral head is less crucial than with displaced fractures.

Because avascular necrosis may take several years to develop, and because even severe

radiographic changes may exist in the presence of trivial symptoms, it does not appear

justifiable to disturb the stable position of fragments impacted in marked valgus in the hope

of preventing subsequent avascular changes.

Symptoms caused by avascular necrosis-Only two patients of the seven with avascular necrosis

had severe symptoms and both were relieved by insertion of a Moore’s prosthesis (Figs.

12 to 14).

DISCUSSION

Mechanism of impacted femoral neck fractures-Linton (1949) showed that there was little

true difference between so-called “ abduction-valgus “ fractures and adduction displaced

fractures of the femoral neck. In each group of fractures the mechanism is the same-both

arise from a lateral rotation strain. The only distinction is the degree of displacement. The

plane of the fracture is not transverse but spiral, the proximal fragment including the femoral

head with a large beak of bone on the back of the head. In the first degree of displacement

the fragments are impacted and the fracture line appears horizontal on the radiograph. As the

rotational force continues the impaction is broken up, the fragments separate and the plane

of the fracture appears more vertical on the radiograph, although in fact it is the same from

the beginning (Figs. 15 and 16). The term “ impacted “ therefore means only that the injury

has stopped short at the first stage of displacement in response to a force which, if continued,

would have produced a displaced fracture. There is close contact between the fragments but

no interlocking of the bone ends. Nevertheless these fractures are often stable, so that the use

of the term “ impacted “ is justified.

CONCLUSIONS

In this series primary internal fixation gave results superior to those of conservative

treatment for fresh impacted femoral neck fractures from the point of view of mobilisation

and weight-bearing, union ofthe fractures, incidence ofdisimpaction, and final clinical results.

Suggested management-The treatment of choice of fresh impacted femoral neck fractures is

primary internal fixation. This may be performed with a standard or low-angle Smith-Petersen


nail. The low-angle Garden screw has been employed recently in five cases. It has the advantage

of not causing disimpaction during insertion. In addition the screw gives firm fixation of the

fracture and is unlikely to be extruded. The patient may begin to bear weight very soon after

operation.

SUMMARY

I . Seventy patients with impacted fractures of the femoral neck treated from 1953 to 1965

have been reviewed. Forty-seven were treated conservatively and twenty-three by primary

internal fixation.

2. The complications of both methods of treatment are recorded.

3. The prognosis following impacted femoral neck fractures is good. Seventy-nine per

cent treated conservatively and 96 per cent treated by primary internal fixation had excellent

or good results.

4. Primary internal fixation is the treatment of choice.

My thanks are due to the consultants on the staff of the Robert Jones and Agnes Hunt Orthopaedic Hospital,Oswestry, who kindly allowed me to study their cases. Mr J. Rowland Hughes, Mr R. Owen and Mr R. G.Burwell gave me most valuable assistance in the preparation of this paper.

REFERENCES

BANKS, H. H. (1962): Factors Influencing the Result in Fractures of the Femoral Neck. Journal of Bone and

Joint Surgery, 44-A, 931.BRODETTI, A. (1960): The Blood Supply of the Femoral Neck and Head in Relation to the Damaging Effects

of Nails and Screws. Journal of Bone and Joint Surgery, 42-B, 794.CRAWFORD, H. B. (1960): Conservative Treatment of Impacted Fractures of the Femoral Neck. Journal of

Bone and Joint Surgery, 42-A, 471.

CRAWFORD, H. B. (1965): Experience with the Non-operative Treatment of Impacted Fractures of the Neck ofthe Femur. Journal of Bone and Joint Surgery, 47-A, 830.

FIELDING, J. W., WILSON, H. J. Jun., and ZICKEL, R. E. (1962): A Continuing End-result Study of IntracapsularFracture of the Neck of the Femur. Journal of Bone and Joint Surgery, 44-A, 965.

FLATMARK, A. L., and LONE, T. (1962): The Prognosis of Abduction Fracture of the Neck of the Femur.

Journal of Bone and Joint Surgery, 44-B, 324.GARDEN, R. S. (1964): Stability and Union in Subcapital Fractures of the Femur. Journal ofBone and Joint

Surgery, 46-B, 630.HULTH, A. (1956): Intra-osseous Venographies of Medial Fractures of the Femoral Neck. Acta Chirurgica

Scandinavica, Supplementum 214.LINTON, P. (1944): On the Different Types of Intracapsular Fractures of the Femoral Neck. Acta Chirurgica

Scandinavica, 90, Supplementum 86.LINTON, P. (1949) : Types of Displacement in Fractures of the Femoral Neck. Journal ofBone andJoint Surgery,

31-B, 184.

SMITH, F. B. (1959): Effects of Rotatory and Valgus Malpositions on Blood Supply to the Femoral Head.Journal of Bone and Joiizt Surgery, 41-A, 800.

TRUETA, J., and HARRISON, M. H. M. (1953): The Normal Vascular Anatomy of the Femoral Head in AdultMan. Journal of Bone and Joiizt Surgery, 35-B, 442.

TUCKER, F. R. (1949): Arterial Supply to the Femoral Head and its Clinical Importance. Journal of Bone

and Joint Surgery, 31-B, 82.

WOLCOTr, W. E. (1943): The Evolution of the Circulation in the Developing Femoral Head and Neck.

Surgery, Gynecology and Obstetrics, 77, 61.


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