Finally, there are still others, and by far the most numerous, in which a fracture of the socket has been inferred only from a supposed impossibility of reducing the luxated femur, or of retaining it in place after reduction. It need not be said that these last cases are more conclusive to the observer than to the reader.

FRACTURE OF THE RIM OF THE ACETABULUM.

To afford satisfactory evidence, cases of this sort should have been identified by autopsy, or at least by crepitus. Unfortunately, but a small part of the reported cases are thus elucidated, and fracture has been generally inferred because the head of the bone could not be restored to the socket, or could not be kept there. It is probable that when the rim of the socket is broken on the side either of the dorsum or of the foramen ovale, the signs of the displacement do not vary materially from those of the regular luxations. The regular backward displacement, for example, may be complicated with a detached rim, which, if enough be left to engage the head of the bone, in no way interferes with its conditions as a luxation, except that the bone tends to slip backward after being reduced. The same principle probably holds true in the case of fracture of the rim on the side of the foramen ovale, and also of the upper part of the socket, unless the fracture involves the upper insertion of the Y ligament, in which case the detached fragment might be so displaced as materially to modify the position of the limb, especially so far as its flexion or inversion was concerned. Such a luxation would be irregular.

These displacements, especially the displacement backward, demand the usual attempts at reduction by flexion. Although the bone inclines to slip from the socket, it can be retained there, in cases of a sort heretofore considered difficult of treatment, by angular extension, with an angular splint attached to the ceiling or some other point above the patient; or if any

manœuvre has reduced the bone, the limb should be retained, if possible, in the attitude which completed the manœuvre.1

The following case occurred at the Massachusetts General Hospital, under the care of Dr. Gay. The patient, aged thirtysix, a robust and healthy man, fell from the roof of a building, striking upon the right hip. In the recumbent position the leg was shortened and inverted, the toes crossing the opposite instep. Being etherized, the thigh could be flexed at a right angle with the abdomen, there being crepitus in the region of the neck of the femur. The limb, when drawn down, was still shortened half an inch. The patient having died of other injuries, the autopsy showed the head of the bone partially dislocated backward, and resting upon the posterior fractured edge of the socket, the whole posterior wall of the socket having been broken away in a mass. The detached fragment measured one and a half inches square. The posterior surface of the head of the bone was deeply indented by the fractured edge of the acetabulum, against which it had impinged after displacing the portion broken off. A transverse crack extended through the acetabulum from the upper sciatic notch to the foramen ovale. The position of the limb in this case did not differ from that in the usual partial dislocation behind the tendon, and was determined by the same mechanism.2

1 See p. 53.

2 In a case of dorsal luxation with inversion, reported by Maisonneuve (Clinique Chirurgicale, 1863, p. 168), the autopsy showed fracture of the posterior part of the border of the socket.

Sir Astley Cooper's Case No. LXXI. is one of regular dislocation below the tendon of the obturator internus, which tightly embraced the neck of the bone, with shortening and inversion of the limb, although the posterior part of the acetabulum was broken off, and there was other extensive fracture of the pelvis.

Dr. M. Tyer's third case was shown by the autopsy to be a regular backward dislocation with inversion, the posterior and inferior margin of the acetabulum being detached, and displaced toward the coccyx.

On the other hand, in Dr. Tyer's first case, the limb was everted while

FRACTURE IN WHICH THE HEAD OF THE FEMUR IS DRIVEN THROUGH THE ACETABULUM.

In regard to this accident Hamilton well remarks:

"There seems to be no certain rule in relation to the position of the limb; but it is found to take the one direction or the other,

flexed and shortened, an inch and a half of the rim being completely detached at the upper and posterior margin of the acetabulum. The remaining portion of the rim may not have been sufficient to turn the head backward, and thus compel inversion of the limb. In a second case, the toes crossed the tarsus of the other foot, and the autopsy showed a fracture of the upper margin of the rim of the acetabulum. (Glasgow Medical Journal, February, 1830; American Journal of the Medical Sciences, 1831, vol. viii. p. 517.)

For a case of dorsal luxation with shortening, inversion, crepitus, and difficulty of retaining the reduced bone in the socket, see Cooper's "Treatise," etc., Case XXXIX.

In the following case of fractured acetabulum, the upper insertion of the Y ligament was detached. The patient, fifty-eight years of age, was caught by a revolving belt. The right limb was shortened a quarter of an inch, and so far everted and straight that the internal condyle of the left femur lay in the popliteal space of the injured one. The right groin was filled up. Toward its middle, and outside the femoral artery, was a hard, resisting, and obscurely spherical tumor, masked by the glands and swollen tissues. Flexion with outward rotation and local downward pressure failed to reduce the luxation; but on a third trial, flexion and downward pressure during slight abduction, instead of outward rotation, succeeded. Seven months afterward, the death of the patient from another cause showed a united fracture of the socket, comprising the external and anterior third of the rim with the two anterior spinous processes of the ilium. (M. Beraud, Bulletin de la Société de Chirurgie, 1862, tom. iii. p. 185.)

In the above case reported by M. Richet, the trochanter was rotated toward the median line, with the head of the femur facing directly forward, and probably with displacement of the detached bone. But the fact that the round ligament was unbroken would seem to indicate that the luxation was only partial, as might indeed have been inferred from the position of the limb, which, though everted, was not much displaced.

In this connection, M. Richet (Bulletin, p. 226) refers to a case of luxation of Maisonneuve (Revue Médico-Chirurgicale, tom. xvi. p. 48) in which a fragment of a broken acetabulum had in twenty-seven days united with the rest of the rim so firmly that the fracture could hardly be discovered.

probably according to the direction of the force which has inflicted the injury, and perhaps in obedience to circumstances not always to be explained."

In two of the recorded cases the patients recovered, being able to walk; in one of these the head of the femur had become almost completely inclosed in a bony shell. In two other cases the patients died of the injury, which in all was the result of great local violence.2

It may be remarked that when the head of the femur is thus thrust completely within the pelvis, the capsule and surrounding muscles are relaxed, and would not determine the position of the bone.

ASSERTED FRACTURE OF THE ACETABULUM, WITHOUT CREPITUS, FROM A SUPPOSED IMPOSSIBILITY OF KEEPING THE FEMUR IN PLACE.

It has been already remarked that the evidence in this class of cases is unsatisfactory; and it is not unlikely that the bone could have been kept in place by angular extension when other means had failed, or by confining the leg in the position of the final manoeuvre by which it was reduced, as before described.3

1 Practical Treatise, p. 343.

2 In the case of Lendrick, and that of Morel-Lavallée, the accident was supposed to be that of fracture of the neck, from which it may be inferred that the foot was everted. In Case LXXII. of Cooper, the appearance was that of dislocation backward, probably involving inversion. In that of Moore the limb was shortened two inches, slightly flexed and abducted, but without rotation in either direction. Cooper, "Treatise," etc., Cases LXXII. and LXXIII.; Lendrick, American Journal of the Medical Sciences, August, 1839, vol. xxiv. p. 481 (from London Medical Gazette, March, 1839); Morel-Lavallée, Malgaigne, "Traité," etc., tom. ii. p. 881; Moore, Medico-Chirurgical Transactions, 1851, vol. xxxiv. p. 107.

3 See p. 53. In the case of Keate (Cooper, "Treatise," etc., Case LXIX.), the fact that the limb could be drawn down, together with doubtful crepitus, was regarded as evidence of fracture of the socket. For a

FRACTURE OF OTHER PARTS OF THE PELVIS.

A fracture of the pelvis not especially involving the acetabulum can hardly be mistaken for luxation of the hip; and yet the following case under my care may be cited as an instance of a limb the position of which, when first seen, was identical with that of a dislocation, and as in similar cases was probably due to an effort of the patient to relieve the pain of injured tissues.1

The patient, a young man of seventeen years of age, entered the Massachusetts General Hospital, having been caught beneath a heavy piece of machinery which fell from a wagon, striking upon the front of his left thigh just below the groin. Upon examination the thigh was found to be flexed upon the pelvis, and the foot everted. The knee was widely separated

case of Mr. Brodie, of twelve weeks' standing, where failure to reduce a dorsal dislocation was attributed to fracture of the socket, although none of its indications were present, see the Lancet, vol. xxiv. p. 671.

The following case of supposed fractured socket without crepitus is one of several reported by M. Richet. A young man fell in dancing, while endeavoring to fling up his leg to the level of his partner's face. The leg was much inverted, and three quarters of an inch shortened, the head of the femur being felt upon the dorsum. The bone was repeatedly reduced, and as often escaped. The patient was ultimately placed in a fracture apparatus with extension, and two years after walked lame, the head of the bone rising upon the ilium at each step. No crepitus was felt, the diagnosis being based upon the supposed impossibility of keeping the head in the socket. (Bulletin de la Société de Chirurgie, 1862, tom. iii. p. 251.)

1 A case of fracture of the ilium yielded crepitus under pressure upon the anterior and upper part of the ilium, the leg being shortened three quarters of an inch, and the foot slightly everted. After extension by the double inclined plane for several weeks the deformity disappeared. (Lancet, vol. xliv. p. 877.)

In a case of fracture of the ilium, the right leg was half an inch shorter than the left, and slightly everted, with flattening of the region of the trochanter, the knee being also abducted. Pressure on the anterior superior spine produced crepitus attended with acute pain in the joint. (Lancet, vol. xv. p. 575.)