PART III. LOWER EXTREMITY. (Part 1)

PART III. LOWER EXTREMITY. CHAPTER XXXVI. DISLOCATIONS OF THE HIP. Surgical Anatomy. — The hip- joint is a typical ball-and-socket articulation, and the depth of the acetabulum is such that the integrity of the joint is much less dependent upon the ligaments than is the case in the shoulder-joint. Numerous muscles are at- tached to the upper end of the femur and the great trochanter, all of which exert more or less of an upward or inward pull, their action being much more apparent in fracture of the neck of the femur than in dislocations of the hip. The muscle of greatest im- portance in this region is the obturator internus which is inserted into the digital fossa after having emerged from the pelvic cavity through the lesser sacro-sciatic notch. If the head of the bone passes under this tendon we have the sciatic form of dislocation. When it passes over the muscle we have the iliac type in which the head of the bone rests on the dorsum ilii. The hip has five liga- ments : ligamentum teres, the capsule, the cotyloid, transverse, and ilio-femoral. The ligamentum teres passes from the ovoid depres- sion on the head of the femur to the margins of the fossa acetabuli. The capsular ligament surrounds the joint, is attached at its inner end to the margins of the acetabulum, while the opposite end is attached to the femoral neck. The anterior portion of the capsule extends downward and outward as far as the spiral line of the femur, while the posterior portion of this ligament reaches to within a half inch of the posterior intertrochanteric line. The capsule is lined with synovial membrane and possesses a number of accessory thickenings along the lines of the greatest and most frequent strains. The upper and anterior portion of this tube- like ligament is the heaviest. The posterior inferior portion is comparatively thin, loose and lax. The cotyloid ligament is an intracapsular fibro-cartilaginous ring attached to the margins of the acetabulum; it serves to deepen the cavity and strengthen the joint. Where it crosses the cotyloid notch, it is known as the transverse ligament. The above ligaments are all more or less 515 516 FRACTURES AND DISLOCATIONS essential factors in the hip, but the ligament of b}^ far the greatest importance is the ilio-femoral or Y -ligament of Bigeloic. This con- sists of an accessory thickening in the anterior portion of the cap- sule. Its lower extremity is attached to the anterior intertro- chanteric line, while its upper end is attached, with the straight head of the rectus, to the anterior inferior iliac spine. In exten- sion of the thigh this ligament is tense, and limits motion at the hip ; in flexion it is relaxed. In a person of average build it is Fig. 569. — The ilio-femoral or Y-ligament of Bigelow, dislocations of the hip. most imijortaut structure in said to possess a tensile strength of two hundred and fifty pounds or more, and thus it will be readily understood that this ligament is rarely torn in dislocations of the hip. The head of the femur when displaced may lie anywhere about the acetabulum, depending on the manner in which violence was applied at the time of the accident, and the subsequent action of the muscles and ligaments attached to the bone. Although the head may lie in almost am- position around the acetabular ring, yet it almost invariably leaves the joint through a rent in the lower DISLOCATIONS OF THE HIP 517 portion of the capsule. After escaping from the socket it usually rides upward either in front of, or behind the acetabulum. Ac- cordingh^ numerous classifications have been given of dislocations of the hip, all of them based on the position occupied by the dis- placed head. There are two main groups deserving of consider- ation, namely, anterior and posterior. The resultant attitude as- sumed by the lower extremity is purely a question of mechanics, depending upon the relations of the displaced head and the influ- ence of the Y-ligament. Whatever position the femoral head may find, the distance between the anterior inferior spine and the spiral line cannot exceed the length of the ilio-femoral ligament. The Fig. 570. Fig. 571. ^ig. 570. — Iliac dislocation of the hip. The higher the head rests on tlie iliani Lore pronounced will be the inward rotation of the thigh provided the Y-ligament Fi^ the more pn is not ruptured. Fig. 571. — Sciatic dislocation of the hip. The head rests in the sciatic notch. action of this ligament, under these conditions, might be likened to that of a ''toggle joint" or ''shackle," which, though movable at one end, maintains a more or less fixed relation between the attached objects. If the head, therefore, is displaced outward and backward, the knee must of necessity come forward and inward, and in like manner the other characteristic deformities accom- panying the various dislocations of the hip, may be readily under- stood if one appreciates the anatomy, particularly the action of the ilio-femoral ligament. A second element in the production of deformity is the angle at which the femoral neck joins the shaft, and the consequent 518 FRACTURES AND DISLOCATIONS leverage exerted by the ueck when the head of the bone is ont of the socket. Thus, if the posterior aspect of the neck lies in con- tact with the OS innominatum, as in the anterior displacements, Fis:. 573. Fig. 572. — Ilio-pectineal dislocation of the hip. Fig-. 573. — Pubic dislocation of the hip. Fig. 575. Fig. 574. — Obturator or thyroid dislocation of the hip. Fig. 575. — Perineal dislocation; an exaggeration of the obturator type. outward rotation must be the result; when the reverse condition is true, the anterior surface of the neck lying in contact with the hip bone, as in posterior dislocations, inward rotation of the thigh will be present. The depth of the socket and the heavy ligaments DISLOCATIONS OF THE HIP 519 surrounding the joint account for the extreme rarity of disloca- tion of this articulation. If the antero-superior iliac spine be connected by a line with the most prominent portion of the tuber ischii, the acetabulum will be approximately bisected, the line passing just across the tip of the great trochanter. This is known as Nelaton's line and forms the dividing line between anterior and posterior luxations. Fig. 576. — High dorsal dislocation of the hip with eversion or outward rotation which is only possible when the outer arm of the Y-ligament is ruptured. If the head lies posterior to this line the condition will be known as a posterior dislocation and the exact position at which the head comes to rest will determine the type of backward luxation present. In like manner anterior dislocations are subdivided according to the point at which the head comes to rest in front of Nelaton's line. The more usual dislocations occurring at the hip may be classified as follows: Posterior luxations Anterior luxations rlliac I^Sciatic Ilio-pectineal Pubic Obturator -Perineal 520 FRACTURES AND DISLOCATIONS Extreme and unusual conditions sometimes occur but for prac- tical purposes it is inadvisable to attempt their consideration in a classification. In eases of great violence, in which the Y-ligament is torn, the head may lie anywhere in this region and the symp- toms accompanying the dislocation will be atypical. The condition may, in rare instances, be compound or complicated b^' fracture. Etiology. — Dislocations of the hip constitute from one to two percent of all luxations. The}' occur most frequenth^ between the fifteenth and forty-fifth years, although they may be seen at any age. The increasing brittleness of the bones as age advances, ren- ders dislocation extremely uncommon in the aged. It occurs about eight times more often in males than in females. Of the various types of displacements, the dorsal iliac is by far the most common. Next in order of frequency is the obturator, a subdivision of the anterior. Symptoms. — Severe, sickening, localized pain, loss of function, and restricted mobility are symptoms which are common to all forms of dislocation of the hip. Deformity, however, will vary with the position occupied by the displaced femoral head. In the iliac type, the head of the bone lies above and behind the acetabulum, being prevented from occupying a higher position by the restraining action of the untorn ilio-femoral ligament. The thigh is slightly flexed, rotated inward, somewhat adclucted, and apparently shortened to the extent of about two inches. The pa- tient's suffering is greatly increased and rigid resistance is felt when passive motion is attempted, especially abduction. A com- plication of this condition is occasionally observed when the upper posterior portion of the rim of the acetabulum is fractured, and the fragment displaced with the head. Under these circumstances, the head leaves the socket at the point of fracture instead of through the usual rent in the lower part of the capsule. Reduction may be possible by simple traction, since the obstructing portion of the acetabular rim is no longer intact. Crepitus may occur as the serrated surfaces pass, often rendering the condition extremely difficult to differentiate from fracture of the femoral neck. The condition might, more properly, be described as a fracture of the acetabulum, complicated by dislocation. In iliac luxation of the hip there is no tendencj^ towards spontaneous recurrence of deformity following reduction, unless the condition is complicated b}' fracture of the acetabular rim. In simple dorsal dislocations, DISLOCATIONS OF THE HIP 521 passive flexion of the thigh meets with less resistance than motion in any other direction. Loss of function is complete. There are a few reported eases of dorsal dislocation with eversion of the thigh as a result of laceration of the anterior arm of the Y-ligament. The head of the hone may lie in the sciatic notch, instead of on the dorsum of the ilium, the condition then being known as the sciatic form of posterior dislocation. Under such circumstances, Fig. 571 Fig. 5 77. — -Attitude in dorsal luxation of the hip. Thigh shortened, adducted and rotated inward. Fig. 578. — Attitude in anterior luxation of the hip. Thigh lengthened, abducted and rotated outward. flexion and adduction of the thigh will be more pronounced. We have practically the same dislocation whether the head lies in the sciatic notch, or on the dorsum ilii, the difference being one of degree only. As previously explained, the determining factor be- tween these two types of posterior dislocation, is the obturator internus. The symptoms in forward dislocation are the same as those just described as far as pain and loss of function are concerned. The 522 FRACTURES AND DISLOCATIONS deformity, however, is unlike that seen in posterior luxations be- cause of the difference in the positions occupied by the head. In the ilio-pectmeal luxation, the head rests on the horizontal ramus of the pubis, in the region of the ilio-pectineal eminence, in which position it may be palpated. Outward rotation is marked, though abduction and flexion are slight, if present at all. The capsular rent is in the lower or lower anterior portion of the liga- ment. Numbness and pain may be present along the course of the anterior crural nerve if pressure has been exerted upon it by the displaced head. Pressure upon or injury to the femoral ves- Fig. 579. Figs. 579 and 580. — Old unreduced dorsal dislocation of left hip of thirty-tive years' standing. Patient unable to fully extend thigh though able to get about by the aid of a built-up shoe and cane. Note the shortening, adduction and inward rotation of thigh. The shortening is more pronounced than is usual in recent cases. (Toes of left foot lost through freezing.) sels has been observed in some instances. Slight shortening of the lower extremity usually exists, and passive motion, especially in- ward rotation, meets with solid resistance. If the head of the bone continues further in its inward course, it may come to rest on the symphysis pubis or above the horizontal ramus, the dislocation then being spoken of as symphyseal or supra- pubic. These two conditions are but exaggerated forms of the ilio-pectineal luxation, and accordingly the symptoms will be more pronounced and the danger to the anterior crural nerve and femoral vessels is greater. In either of these forms the head of the bone DISLOCATIONS OF THE HIP bZ6 may be felt as a globular prominence somewhere along the hori- zontal ramus of the pubis. A few cases have been reported in which the head occupied an extremely high position, directly below the anterior superior iliac spine. This is but a variation of the ilio-pectineal form, and is exceedingly rare. In the o'hturator dislocation, another form of anterior displace- ment, the head of the bone fails to ride upward after leaving the acetabulum but comes to rest in the obturator foramen. This form of dislocation is next, in point of frequency, to the iliac type. The limb is slightly flexed, abducted, and rotated outward, and the displaced head may be palpated without difficulty. A depres- sion is noted in the position formerly occupied by the trochanter, the thigh appears lengthened and full extension is not possible. The perineal luxation is simply an exaggeration of the obturator form of displacement, in which the symptoms (especially abduc- tion) are more pronounced. The condition is very unusual. The prominence produced by the head may be recognized both by in- spection and palpation. The ischio-pubic rami may be fractured as the head passes across this portion of the pelvis into the perineum. There is an extremely rare form of downward luxation known as the infra-cotyloid, which is analogous to the luxatio erecta oc- curring in the shoulder. The head of the bone is forced from the acetabulum while the thigh is in extreme flexion, and rests in dis- placement on the body of the ischium. The thigh is maintained in extreme flexion until the head is replaced. This condition can neither be classed with the anterior, nor with the posterior dislo- cations, since the head is crossed by Nelaton's line. This luxation is so extremely rare that it might better be considered as a surgical anomaly rather than to describe it as a type. Another very unusual displacement is known as central dislo- cation of the hip, in which the head is driven through the bottom of the acetabulum. This condition has already been described on page 504 under ' ' Fractures of the Lateral Portions of the Pelvis. ' ' Diagnosis. — The diagnosis is based on the symptoms just de- scribed. Recognition of the condition is seldom really difficult, although it is not uncommon to see a dislocation of the hip mis- taken for fracture of the femoral neck, or even confounded with some forms of pelvic fracture. The fact that the usual impacted fracture of the neck of the femur should not be broken up, renders 524 FRACTURES AND DISLOCATIONS it essential that the surgeon be at least reasonably sure of the existing conditions before an attempt is made at the reduction of a luxated hip. In fracture of the neck with impaction, the lower extremity lies in a helpless attitude, shows some shortening and slight outward rotation. There is no abnormal fixation of the parts aside from that produced by reflex muscular spasm. Inward rotation is extremel}^ rare in fracture of the femoral neck. The most common dislocation of the hip is the dorsal, in which adduc- tion and inward rotation are pronounced. The great majority of dislocations are on to the dorsum of the ilium or into the obturator foramen, and the characteristic de- formities accompanjdng these displacements will- suggest the con- dition when the case is first inspected. In dislocations it will usually be possible to palpate the femoral head, which is, of course, impossible in fractures of the neck. In dislocations, mobility at the hip is much restricted in contradistinction to the normal mo- bilit}^ seen in impacted fractures, and the increased mobility occur- ring in fractures of the unimpacted type. In dislocations crepitus is absent ; in fractures it can almost invariably be elicited. Dorsal dislocation with fracture of the acetabular rim, may be quite diffi- cult to differentiate from fracture of the femoral neck. Crepitus ma}^ be present in either injur}'. In the former, motion is re- stricted as in all uncomplicated dislocations of the hip, while in the latter, it may be restricted or abnormally increased. Reduc- tion of a simple dorsal dislocation is only accomplished by some system of manipulations, such as Bigelow's, while on the other hand, displacement accompanying fracture of the acetabular rim may be reduced without difficulty by simple traction and counter- traction, and there is a strong tendency towards spontaneous re- currence of deformity. In fractures it is almost always possible to rotate the thigh, and with the finger placed on the trochanter, the arc described by the femoral neck can be ascertained and compared with the uninjured side, and the surgeon can estimate whether or not the center of this arc is in the acetabulum. In dislocations the fixity of the thigh precludes anything but the slightest rotation. When doubt exists as to the nature of the injury the X-ray should be employed to clear up the diagnosis. Treatment. — The first indication of treatment is the reduction of the displaced head. The method of accomplishing this purpose DISLOCATIONS OF THE HIP 525 must, of necessity, vary with the type of dislocation present. The object in all instances is to cause the head to retrace the course taken by it in leaving the cavity. All manipulations must be performed with due appreciation of the strength and attachments of the ilio-femoral ligament (see ' ' Anatomy, ' ' page 516) . It should be distinctl}^ understood that the common, dorsal dislocation can- not be dragged back into position by simple traction and counter- traction without the employment of