Dislocations and Fractures of the Talus

r Dislocations and Fractures of the Talus JOHN J. FAHEY, M.D., F.A.C.S.* JEROME L. MURPHY, M.D.**

Dislocations, major fractures and fracture-dislocations of the talus are infrequent injuries and pose a problem in management because of the frequent and formidable complication resulting from open wounds, skin necrosis from bony pressure, imperfect reduction and aseptic necrosis. In order to minimize these changes, reduction must be prompt and effective. Reports, based chiefly on extraosseous studies of the circulation of the talus, 17. 81 indicated that the talus had a limited margin of safety because of a scanty blood supply and that, even in undisplaced fractures of the neck of the talus,17 necrosis of the body was not uncommon. However, a previous study of dried specimens in 1904 found vascular foramina on the superior, lateral and inferior surfaces of the neck as well as on the medial surface of the body, the larger and more abundant foramina being on the inferior surface of the neck. This study indicated a more liberal circulation to the talus and corresponded more with current clinica133 and extraosseous and intraosseous studies of the circulation of the talus. 8 The latter authors found that the blood supply of the talus is derived from three main arteries of the leg through a periosteal vascular network and by a sling anastomosis formed from the artery of the tarsal sinus arising from the dorsolateral arteries and from the artery of the tarsal canal arising from the posterior tibial artery. The head was supplied by vesseIs entering from the superior surface of the neck and the inferolateral aspect of the neck. The main source of supply of the body was found to come from vessels that entered the anteroinferior portion of the neck and also the medial surface of the talus below the articular facet. Less important vessels entered the body from the superior surface of the neck, the anterolateral surface of the body and the posterior tubercle. It is difficult to explain why the talus in triple arthrodesis and other From the Department of Orthopedic Surgery, St. Francis Hospital, Evanston, Illinois * Associate Professor of Orthopedic Surgery, Northwestern University Medical School; Chief of Orthopedic Surgery, St. Francis Hospital ** Associate, Attending Staff, Cook County Hospital, Chicago

79

80

JOHN J. FAHEY, JEROME

L.

MURPHY

operations which apparently disrupt its chief source of blood supply is spared from the complication of aseptic necrosis in such a high percentage of cases (93.8 per cent),u While undisplaced fractures of the neck are likely to escape necrosis, fractures of the neck associated with subtalar dislocation will result in aseptic necrosis in 50 per cent of cases. 33 Where there is a fracture of the neck or body with dislocation of the body from both the subtalar and ankle joints, the body of the talus rarely escapes necrosis. Sullivan and Jackson,32 in a comparative study, found that the prognosis of talar fracture-dislocations in children and in adults is about the same, with a satisfactory result in only half the cases.

DISLOCATIONS

The talus may be dislocated from one or more of its articulating surfaces, talotibial, talonavicular and talocalcaneal. Subluxation and fracture-dislocation of the ankle are such frequent injuries that they will be excluded from this presentation. However, the infrequent talotibial dislocation that is unassociated with a fracture will be discussed. Talotibial Dislocation Unassociated with Fracture Talotibial dislocations unassociated with fracture may be classified as anterior, posterior, medial, a combination of these and also divergent. Wilson, Michele and Jacobson,34 in a review of 14 cases of ankle dislocation without fracture, added two of their own, both with disruption of the tibiofibular joint. In their review they were unable to determine the incidence of tibiofibular disruption. Of the 16 cases, 50 per cent were compound, and these were usually medial in type, often associated with anterior or posterior displacement. W ood 35 reported a case of posterior dislocation of the talus on the tibia with associated locking of the fibula behind the tibia. Other authors, including Fonda,6 Sloane and Coutts,29 North,24 and Kelly and Peterson,l° in case reports of tibiotalar dislocation without fracture made no mention of the integrity of the distal tibiofibular articulation. Dislocation of the talotibial joint without fracture and without disruption of the distal tibiofibular articulation is extremely rare. Conwell and Alldredge4 and Haines 7 presented single case reports of compound medial talotibial dislocation in which there was no fracture and the distal tibiofibular joint remained intact. In a study of our cases of dislocations of the ankle unassociated with a fracture, there were only two cases in which it could be ascertained with a reasonable degree of certainty that the tibiofibular joint was intact. In both

DISLOCATIONS AND FRACTURES OF THE TALUS

81

instances, the talus was dislocated posteriorly and medially. Since the narrowest part of the superior articular surface of the talus is in the ankle mortise in plantar flexion and instability of the ankle is at its maximum in this position, it is likely that the mechanism producing the dislocation in our two cases was a combination of plantar flexion and inversion of the foot. In this type of dislocation, the foot is plantar flexed and inverted and displaced backward, and the anterior lip of the lower articular surface of the tibia is palpable beneath the skin. There is a concavity posteriorly in the region of the tendo achilles with the prominence of the heel. Both were closed injuries and were easily reduced by traction with the knee flexed to relax the calf muscles, applying the traction in the position of deformity followed by manipulation into the neutral position. Immobilization in a short leg cast with the foot at a right angle was maintained for six weeks with gradual resumption of activity. CASE I. L.S., a 44 year old woman, fell down a flight of stairs, twisting her left ankle. With the foot held in plantar flexion and inversion, the anterior margin of the tibia presented itself beneath the skin as a sharp border, the heel was prominent and there was a concavity posteriorly in the region of the tendo achilles. The skin was intact with adequate circulation and sensation. X-rays of the ankle showed posteromedial displacement of the talus (Fig. I). One hour after injury, closed reduction was accomplished with intravenous morphine analgesia, and the ankle was immobilized at a right angle with a short leg cast for 6 weeks. Examination 3 years after injury revealed no instability or complaint referable to the ankle.

It is surprising that these injuries and trimalleolar fractures with posterior dislocation of the talus, while disrupting the ligaments of the ankle, are so infrequently followed by instability of the ankle.

Figure 1 (Case I). Anteroposterior and lateral roentgenograms of the left ankle show a posteromedial dislocation of the talus from the ankle mortise unassociated with a fracture or disruption of the inferior tibiofibular ligaments.

82

JOHN

J. FABEY,

JEROME

L.

MURPHY

Subtalar Dislocation The most common of the dislocations of the talus have variously been designated as subastragalar,30 subtalar, subastragaloid28 and talocalcaneonavicular dislocations. ss Since the essentials of a subtalar dislocation include disruption of both the talocalcaneal and talonavicular joints, the term talocalcaneonavicular is the most descriptive. However, subtalar dislocation is the most widely used term, even though it carries the connotation that the talus is disrupted only inferiorly from the calcaneus. The usual classification of the subtalar dislocation is medial or lateral. While posterior or anterior dislocations have been described, they are usually regarded as part of the displacement with medial or lateral dislocations. In the medial type the foot is usually displaced posteriorly, and in lateral displacements the dislocation is forward. Medial dislocation is the most common. Leitner12 reported 42 cases of subtalar dislocation, 36 of the medial type, five lateral and one posterior, and found 241 published cases of fresh dislocations,2 usually single cases. Subtalar dislocation results from a strong plantar flexion injury associated with inversion or eversion, thus producing either a medial or lateral subtalar dislocation. Because of the not uncommon association of supination at the talotibial joint, and the apparent necessity of having the talotibial joint intact while the forceful injury dislocates the talocalcaneonavicular joints, Leitner13 thought that subtalar dislocation represented the primary stage of a total dislocation. In medial dislocation the foot is plantar-flexed, adducted and supinated and the head of the talus is prominent over the dorsolateral side of the foot. The overlying skin is tight and blanched. The lateral side of the foot is long and the medial border short. The navicular and sustentaculum tali can be palpated medially. In outward dislocations the foot is pronated and abducted. 2The toes may be dorsiflexed in a medial dislocation and plantar flexed in a lateral dislocation. An impacted fracture of the medial portion of the head of the talus by the navicular, a fracture of the posterior process of the talus, or a fracture of the navicular may be associated with a medial dislocation; a fracture of the lateral malleolus, calcaneus or cuboid may occur in conjunction with a lateral displacement. 2 TREATMENT. The treatment must be prompt because of the danger of necrosis of the tightly stretched skin over the talar head. When subtalar dislocation occurs, the talus loses its support inferiorly and anteriorly and assumes an equinus position, and it is necessary to bring the foot into plantar flexion so that it is in line with the head of the talus before manipulating the foot.sS When encountered early, within hours of the injury, subtalar dislocation may require only morphine analgesia to effect reduction. Traction on the foot and heel in the direction of the deformity and countertraction with the knee flexed to relax the gastrocnemius are followed by manipulation of the foot into the neutral position. The foot is immobilized

DISLOCATIONS AND FRACTURES OF THE TALUS

83

in a neutral position and at a right angle for six weeks by a short leg cast. A walker may be added in three to four weeks if there is no discomfort, swelling or an associated wound. Twenty cases of subtalar dislocation have been treated on our service, five of which are recent and have been excluded here. Thirteen cases were seen early and two were seen late. In 12 cases the dislocation was medial and three were of the lateral type. Eleven of the patients were men and four were women. The ages ranged from 24 to 71 years-the average was 44 years. Seven of the 15 cases had either a chip fracture of the talus, a fracture of the posterior process, or a fracture elsewhere. The two most common etiological factors were automobile accidents-six cases; falls from a height-five cases. Two of the patients incurred injuries while engaged in athletics; one fell on the street, and in one instance no mention was made of the etiology. In the 13 cases of acute dislocation treated, and in which records were adequate, reduction was accomplished by closed manipulation in eight cases (seven medial; one lateral). In five of these eight cases, no anesthesia was required. Five of the 15 patients were operated upon under general anesthesia-three had recent injuries and two, old injuries. In the three with recent injuries, namely, one medial and two lateral subtalar dislocations, there were obstacles to reduction. Eight of the 13 patients with acute dislocation were examined one to three years following reduction. Five had normal motion and no complaints. Three had restriction of lateral motion of 10 to 25 degrees at the talocalcaneal joint and 5- to 10-degree limitations at the ankle and noticed aches or pains only occasionally with weather change or excessive activity. In the patient who had a compound injury, lateral motion was restricted to one-third of normal. Although most subtalar dislocations can be managed by closed manipulative methods, various obstacles to reduction may occur that make surgical intervention necessary. In medial subtalar dislocation, the distal lateral limb of the cruciate crural ligament can restrain the head and neck of the talus in a lateral position by passing inferior and medial to the neck (Case II, Fig. 2, D). CASE II. L.P., a 65 year old man (Fig. 2, A.), fell from a 6-foot ladder landing with his left foot inverted, striking the lateral aspect of the foot against the ground. An anteroposterior projection of the foot was obtained by placing the cassette under the sole of the foot and directing the x-ray tube over the midtarsal joints, and a lateral view was obtained by placing the cassette on the lateral aspect of the foot (Fig. 2, B). There was a medial and inferior dislocation of the scaphoid from the head of the talus and interruption of the talocalcaneal joint (Fig. 2, C). Closed manipulation with morphine analgesia was unsuccessful and, when closed reduction under general anesthesia failed, the patient was operated upon. The head of the talus was buttonholed through a rent in the capsule (Fig. 2, D) and the distal lateral limb of the cruciate crural ligament passed medially and inferiorly to the neck, obstructing reduction. Reduction was easily accomplished following release of the obstructing mechanism. A short leg cast was applied, immobilizing the foot at a right

84

JOHN

J.

FAHEY, JEROME

L.

MURPHY

Figure 2 (Case II). A, Photograph shows plantar flexion and inversion deformity of the left foot and ankle and a prominence of the talar head beneath the skin on the lateral aspect of the dorsum of the foot as a result of a fall from a ladder with the foot inverted. A 1, Demonstrating the technique of obtaining an anteroposterior view of the foot by placing the cltssette under the sole of the foot and directing the x-ray tube over the midtarsal joints. B, Demonstrating the technique of obtaining a lateral view of the deformed foot and ankle in a medial subtalar dislocation by placing the cassette on the lateral aspect of the foot. If the dislocation is lateral, the cassette is placed on the medial aspect. C and C1, Anteroposterior roentgenogram of the foot and a lateral roentgenogram of the foot and ankle showing a medial and inferior dislocation of the scaphoid from the head of the talus and a dislocation of the talocalcaneal joint. D, Photograph shows the head of the talus buttonholed through a rent in the capsule and held laterally by the distal lateral limb of the cruciate ligament. Open reduction was necessary to release this obstacle to reduction. angle for 6 weeks. Two years following injury, the patient had a normal gait and no pain, and motions of the ankle and foot were normal except for a lO-degree loss of inversion.

Closed reduction of a medial subtalar dislocation may also be precluded by the piercing of the extensor digitorum brevis by the head of the talus, or by impaction of the fractured head of the talus into the navicular. 12 While the lateral subtalar dislocations are less frequent than the medial

DISLOCATIONS AND FRACTURES OF THE TALUS

85

Figure 3 (Case III). A, Photograph shows the eversion and lateral displacement of the foot and ankle of a lateral subtalar dislocation in a 26 year old man injured while jumping 6 hours previously. The skin was blanched and stretched over the inner aspect of the foot overlying the head of the talus. There were blisters over the inner side of the ankle. Band BI, Anteroposterior and lateral roentgenograms of the ankle and foot show a supination tilt of the talus in the ankle mortise and the calcaneous and scaphoid bones to be dislocated from the talus and displaced laterally with the foot. 0, Photograph shows the posterior tibial tendon looped around the superolateral neck of the talus in a lateral subtalar dislocation. Open reduction was necessary to release the obstacle to reduction.

86

JOHN J.

FAHEY,

JEROME

L.

MURPHY

type, they are more likely to have obstacles of obstruction. In a review of the literature, Leitner found 162 cases of medial dislocation, of which 8 per cent showed obstruction, and 59 cases of lateral dislocation, of which 15 per cent showed obstruction. 12 In lateral subtalar dislocation, the head and neck of the talus can be held medially by the posterior tibial tendon wrapped around the neck on its lateral side. 21 Two of our three lateral subtalar dislocations had obstacles to reduction-one with the posterior tibial tend9n looped around the neck of the talus superolaterally (Case III, Fig. 3, (;j: Another lateral dislocation was an open injury in which the tibialis posterior and long flexors of the toes locked under the neck of the talus, thereby preQluding reduction until the tendons were released (Fig. 4). CASE III. T.R., a 26 year old man, was seen 6 hours after a fall while jumping in the woods. The foot and heel were everted and displaced laterally. The skin was taut over the head of the talus medially and there was blistering on the inner side of the ankle (Fig. 3, A). Roentgen,Qgl'ams showed an associated fracture of the lower fibula and there was a modera't~ supination tilt of the superior articular surface of the talus (Fig. 3, B). The calcaneus and scaphoid bones were dislocated from the talus and the foot displaced laterally (Fig. 3, B). Closed reduction was unsuccessful and, at operation, the posterior tibial tendon was found to be looped around the lateral aspect of the neck of the talus (Fig. 3, C), holding it medially. Reduction was carried out after the tendon was replaced in its normal relationship and, following closure of the wound, the extremity was placed in a nonweight-bearing short leg cast for 7 weeks. Eight months following injury, the patient had no pain and inversion and eversion were limited to two-thirds of normal.

Figure 4. Photograph shows the head and neck of the talus protruding through an open wound on the inner side of the foot in a lateral subtalar dislocation. The tibialis posterior and flexor tendons of the toes had slipped beneath the neck requiring release before reduction could be accomplished. (Courtesy of Dr. Bradley Carr.)

DISLOCATIONS AND FRACTURES OF THE TALUS

87

Leitner12 thought that dorsiflexion and forward traction might disengage the tendon and should be attempted before resorting to open reduction in this type of injury. Where infection results from pressure of the talar head, an open wound or from an open operation, it is probably judicious to preserve the talus and accept limited motion or ankylosis. 2 Two patients with medial subtalar dislocations were seen late. Both had sustained their dislocations in automobile accidents. One of these, a 47 year old woman, required a triple arthrodesis; the other patient, a 27 year old man who had at the time of injury an associated open intra-articular fracture of the ankle which had resulted in deformity, underwent a pantalar arthrodesis.

Talonavicular Dislocation Traumatic dislocation of the talonavicular joint without fracture is extremely rare. Lewin14 stated that astragaloscaphoid dislocation can occur but does not report any cases. This injury results from a severe twisting force. The talar head buttonholes through the talonavicular capsule, which may act as an obstacle to reduction. McLaughlin18 believes that the most frequent displacing force moves the foot lateralward on the talus. The anterior tibial tendon displaces with the forefoot and may slip under the neck of the talus. The buttonholed capsule may also act as an obstacle to reduction. We have seen two cases of talonavicular dislocation and in both instances the foot was displaced medially and the head was palpable beneath the skin but less prominently than in medial subtalar dislocation. In neither of these cases did x-rays demonstrate subluxation of the subtalar joint (Fig. 5, B; Fig. 6) and in one of them in which operation was carried out (Case V, Fig. 6), the subtalar jOint appeared intact and the ligament of the posterior portion of the foot uninterrupted. When the talonavicular capsule was released by operation, reduction was easy and postoperative x-rays showed the position satisfactory; however, subluxation of the talonavicular joint gradually recurred and subsequently required a triple arthrodesis. It is not, however, easy to interpret the integrity of the talocalcaneal joint on a lateral view roentgenogram. Disruption of the anterior part of this joint or the entire joint may give an illusionary appearance to the contrary. If reduction appears to be unstable after open reduction, Kirschner wire fixation may be necessary to maintain reduction. Immobilization in a nonweight-bearing short leg cast for eight weeks with the foot at a right angle is carried out. While the appearance of the foot is somewhat suggestive of a subtalar dislocation, the deformity is not as pronounced as that in a subtalar dislocation, particularly in the hind foot (Fig. 5, A). CASE IV. S.W., a 64 year old woman, injured her right foot in an automobile accident. Her presenting complaint was pain and deformity of the foot and on examination she had swelling of the outer aspect of the foot with some inversion (Fig. 5, A). X-rays showed dislocation of the talonavicular joint with the head of the talus situated lateral and dorsal to the tarsal navicular (Fig. 5, B).

88

JOHN J. FAHEY, JEROME

L.

MURPHY

Figure Figure 55 (Case (Case IV). IV). A, A, Photograph Photograph shows shows aa plantar plantar flexion flexion and and inversion inversion dedeformity formity of of the the foot foot and and ankle ankle in in aa 64 64year year old old woman woman who who had had aa dislocation dislocation ofof the the talonavicular talonavicular joint joint as as aa result result of of an an autoautomobile mobile accident. accident. 1, Anteroposterior view roentB and BBt, Band Anteroposterior view roentgenogram genogram of of the the left left foot foot and and aa lateral lateral roentgenogram roentgenogram of of the the foot foot and and ankle ankleshow show medial medial and and inferior inferior dislocation dislocation of of the the scaphoid scaphoid from from the the head head of of the the talus. talus. The The talocalcaneal talocalcaneal joint joint appears appears undisturbed. undisturbed.

Closed reduction was easily accomplished without anesthesia and the foot was immobilized for 8 weeks at a right angle in a short leg non weight-bearing cast. The patient was seen 2 years and 10 months following injury and was asymptomatic. She was walking with a normal gait but had minimal swelling of the ankle. There was a 5-degree loss of dorsiflexion, 15-degree loss of plantar flexion and 1O-degree loss of inversion. CASE V. R.W., a 42 year old woman, who fell from a 6-foot height, complained of pain in the left ankle and knee and the foot was plantar flexed and inverted. X-ray examination disclosed a dislocation of the talonavicular joint with the navicular displaced medially and superior to the head of the talus (Fig. 6). The subtalar joint appeared undisturbed. There was an associated fracture of the tibial plateau on the same side that required open reduction. Successful closed reduction under spinal anesthesia was carried out; however, 5 days after reduction, roentgenograms revealed recurrence of the deformity. An open reduction was performed and the subtalar joint was found uninterrupted posteriorly. In spite of what appeared to be a stable reduction and cast immobilization, subsequent x-rays disclosed progressive recurrence of the deformity which required a triple arthrodesis.

I

DISLOCATIONS AND FRAUl'URES OF THE TALUS

89

In a similar case (Case VI) the patient had an obvious dislocation of the taloscaphoid joint associated with a subluxation of the calcaneocuboid joint but no apparent disruption of the talocalcaneal joint on roentgenographic examination (Fig. 7, B); however, inversion of the ankle and the audible snap on reduction would cast doubt that the talocalcaneal joint was undisturbed. CASE VI. I.H., a 53 year old woman, was admitted with swelling deformity of the ankle (Fig. 7, B) and foot following a fall down the steps on a boat. Examination showed swelling of the foot and ankle and the foot was held in 20 degrees plantar flexion from which point it could be moved only 10 degrees toward plantar flexion. The heel and foot were inverted 15 degrees (Fig. 7, A). Roentgenograms of the ankle and foot (Fig. 7, B) showed a medial dislocation of the scaphoid on the talus and with some subluxation at the calcaneocuboid joint. There was also an associated fracture of the base of the fifth metatarsal and the talus was slightly tilted in pronation in the ankle mortise. The subtalar joint appeared to be undisturbed in the lateral view. Closed reduction under morphine analgesia was unsuccessful and reduction was carried out under general anesthesia. Reduction was accomplished by strong traction in the deformed position with the knee flexed, then bringing the foot into eversion and dorsiflexion into the neutral position and immobilizing it in a short leg cast. At the time of reduction an audible snap could be heard in the subtalar region.

Jacobs 9 presents a case report of progressive talonavicular dislocation occurring over a period of years, unassociated with trauma. Dislocation of the talus from the calcaneus, unassociated with talotibial or talonavicular dislocation but with disruption of the calcaneocuboid joint, has been reported. 1s

Figure 6 (Case V). Roentgenograms of the left foot and ankle of a 42 year old woman who fell from a 6-foot height show a dislocation of the talonavicular joint. The navicular was displaced superiorly and medially to the head of the talus. The talocalcaneal joint appeared uninterrupted.

90

JOHN J. FAHEY, JEROME

L.

MURPHY

Figure 7 (Case VI). A, Photograph of the plantar flexion and inversion deformity of foot and ankle of a 53 year old woman who slipped going down the steps of a boat, rel;lulting in dislocation of the talonavicular joint, subluxation of the calcaneocuboid joint and possible dislocation of the talocalcaneal joint. ,,~ Band Bl, Roentgenograms of the ankle and foot show a medial dislocation of the scaphoid on the talus and subluxation of the calcaneocuboid joint. The talocalcaneal joint appears uninterrupted. A mild pronation tilt of the talus in the ankle is present.

Total or TriPle' Dislocation Total or triple dislocation of the talus from its neighboring joints, talotibial, talocalcaneal and talonavicular,' results from a severe plantar flexion, inversion .or eversion injury of the foot which dislocates the talus anteriorly and'Totates it around a 90-degre~ vertical axis and a 90-degree longitudinal axis so that the head,is directed medially and the calcaneal surface is directed. posteriorly. 'The talus is, displaced on the anterolateral aspect of the foot in front of the lateral malleolus when the mechanism is plantar flexion and inversion (Fig. 9, A),13. 33 and is displaced medially in instances of plantar flexion and eversion o£ the foot (Fig. 10, A).13 Total' dislocation is often associated with an open wound and the talus is comminuted or contaminated so greatly that it is unsalvageable. Where there is no open wound, the skin is stretched tigh1lly over the talus and requires urgent treatment because of the danger of tiecrosis and resulting infection. Manipulative reduction has occasionally peen successful; 8. 20. 22, 33 however, repeated manipulations should be aVtbided because of the danger of skin slough. Open reduction is usually necessb.ry to reduce a total dislocation of the talus and is indicated in the presence of an open wound following

DISLOCATIONS AND FRACTURES

OJ'

THE TALUS

91

debridement provided the contamination is not too great and the comminution does not preclude reduction, and in instances of closed dislocation in which closed reduction fails as the primary treatment. If reduction is not stable, transfixation pins may be used to maintain reduction. The loss of the talus is to be avoided i(possible because o(the plantar flexion and inversion deformity of the foot and ankle, shortening, and the unsatisfactory result which usually requires an arthrodesis of the tibia to the calcaneus or to the calcaneus and other tarsal bones. Even if loss of the blood supply is inevitable, prolonged postponement of weight bearing protects from collapse of newly revascularized bone and many result in a satisfactory outcome, particularly in older persons and those not subjected to strenuous activity. If subsequent symptoms warrant arthrodesis, it can be done more easily when the talus is present and with maintenance of length of the extremity. In the absence of the talus, filling the defect with bone grafts and attempting to bring the tibia into close proximity with the calcaneus is a formidable procedure that may be attended by an infection or a serious circulatory complication. Infection following total dislocation has resulted in amputation. lB. 25 CASE VII. W.B.. a 28 year old man, was seen shortly after an injury to his right ankle and foot as a result of a fall from a ladder. Examination showed a plantar flexion inversion deformity of the ankle and foot and a bony prominence (Fig. 8, A) on the anterolateral aspect of the foot anterior to the lateral malleolus. The skin was blanched over this prominence and he resisted any attempts to move his ankle or foot because of pain. X-rays revealed an anterolateral dislocation of the talus and also a comminuted fracture of the internal malleolus and a displaced fragment from the posterior articular facet of the talus (Fig. 8 B, C). An attempt at closed reduction under anesthesia was unsuccessful. The patient was then prepared for an open reduction and, using a tourniquet, an incision was made over the anterolateral aspect of the foot in the region of the prominence produced by the talus. The talus was rotated back into position, being careful to preserve the portion of the capsule that was still attached to the talus. The comminuted internal malleolus was removed as well as a fragment of the posterior articular facet .. The talonavicular joint appeared somewhatlunstable following reduction and was fixed with a heavy Kirschner wire and~cut beneath the skin (Fig. 8, D). A short leg cast was then applied with the foot at a right angle. The stitches were removed and a new cast applied 2 weeks after the operation. The cast and wire were removed after 8 weeks and active exercises begun. The patient became ambulatory and began partial weight bearing 372 months postoperatively. One and one-half months later, he was bearing full weight without support. Four years postoperatively, the patient complained of occasional pain just above the internal and external malleoli, especially with excessive activity. He had a slight varus of the right heel on walking but there was no limp. The scar and adjacent skin over the anterolateral aspect of the right ankle had a brownish discoloration. Dorsiflexion was limited 10 degrees and plantar flexion 15 degrees and he had only 5 degrees inversion of the ankle as compared to 25 on the normal side. X-rays of the ankle at the time showed no evidence of sclerosis of the talar body. There were, however, degenerative changes of the talonavicular joint and some narrowing of the talocalcaneal joint (Fig. 8, E). He experienced discomfort with weather

92

JOHN J. FAHEY, JEROME

L.

MURPHY

Figure 8 (Case VII). A, Photograph of the right foot and ankle of a 28 year old man who fell 20 feet from a ladder shows the plantar flexion inversion with a prominence on the distal lateral aspect of the foot. B, C, Anteroposterior and lateral roentgenograms of the ankle and foot show an anterolateral dislocation of the talus with a comminuted fracture of the internal malleolus and a displaced fragment from the posterior articular facet of the talus. D, Roentgenograms postoperatively show fixation of the taloscaphoid joint with a heavy Kirschner wire. The fractured fragment from the posterior portion of the posterior facet of the talus is in satisfactory position. E, A lateral roentgenogram of the ankle and foot shows no evidence of increased density in the area of the talus that is not overlapped by the fibula and the internal malleolus. There is some degenerative change at the taloscaphoid joint and narrowing at the talocalcaneal joint.

changes and with excessive walking, particularly on irregular surfaces. While he is not handicapped from carrying out his usual occupation which requires a moderate amount of walking, further degenerative changes and disability may occur.

Even after a patient has been under observation for some years, one cannot be certain the course pursued above is preferable to replacing the talus and fusing the tibiotalocalcaneal joints a few weeks after reduction when the swelling has subsided and the soft tissues have healed sufficiently to carry out a major arthrodesing operation. The age, sex, health and occu-

DISLOCATIONS AND FRACTURES OF THE TALUS

93

pation of the patient, and the experience of the particular surgeon will help dictate the procedure of choice. In open fractures of the talus seen late in which contamination or infection precludes salvage, the talus should be removed and tibiocalcaneal arthrodesis performed when healing has occurred and the infection has become quiescent. CASE VIII. E.D., a 38 year old woman, 18 hours before admission had fallen 30 feet from a ladder while painting her house and sustained an 8 by 10 cm. open wound on the inner side of the left ankle posteriorly to the internal malleolus through which the talus was exposed (Fig. 9, A). The wound was contaminated and lacerated tissue appeared necrotic in areas. The superior surface of the talus was directed anteromedially, the inferior surface was facing backward and the head of the talus was directed medially. The facet for articulation with the fibula was turned inferiorly and the articular facet for the medial malleolus of the tibia superiorly. The talus had been rotated 90 degrees around its vertical and horizontal

l!lgure \:I (Uase Vll1). A, .Photograph shows the protrusion of the talus through an open wound on the inner side of the ankle in a 38 year old woman who fell from a ladder 18 hours previously. B, Anteroposterior and lateral roentgenograms of the left foot and ankl£) show a wide space between the tibia and calcaneus with medial dislocation of the talus. A loose fragment of bone in the posteromedial compartment in the ankle is visualized. The foot is displaced anteriorly in relation to the tibia. Photograph of the inferior surface of the removed talus shows a separated fractured fragment of the lateral fourth of the posterior articular facet of the talus. D, A lateral roentgenogram 6 weeks postoperatively prior to arthrodesis shows the tibiocalcaneal space to be less pronounced. E, Roentgenograms show fusion of the pantalar arthrodesis performed 3 years previously by resecting the calcaneocuboid joint and sliding tibial bone grafts to the calcaneus and scaphoid bones after resection of the surfaces.

e,

94

JOHN

J.

FAHEY, JEROME

L.

MURPHY

axes. Anteroposterior and lateral roentgenograms (Fig. 9, B) showed a wide space between the tibia and calcaneus as well as the medial displacement of the talus. There was a loose fragment of bone in the medial and posterior compartment of ankle. The patient was operated upon under general anesthesia. The degree of contamination precluded salvage of the talus and it was removed. There was also a large loose fragment which proved to be the lateral one-fourth of the posterior facet (Fig. 9, C). The space was thoroughly cleansed and flushed with saline, the wound was closed with interrupted sutures and the foot, while pushed backward and held in eversion with the knee flexed, was immobilized at a right angle in a short leg cast. This cast was split and spread to accommodate for swelling. Postoperatively, the patient received 10,000 units of tetanus antitoxin and was placed on antibiotics. Except for some necrosis of the midportion of the wound, healing was satisfactory. A lateral roentgenogram of the ankle (Fig. 9, D) six weeks after the operation showed the tibiocalcaneal space, as a result of the loss of the talus, to be less prominent. Because of the varus deformity of the foot and the frequent complications following loss of the talus, the patient was operated upon under general anesthesia. Through an anterolateral incision the calcaneocuboid joint was resected and 2 sliding grafts, removed from the lower tibia, were used to bridge the tibiocalcaneal and tibioscaphoid joints. Cancellous bone removed from the lower tibia was used to supplement the fusion. Anteroposterior and lateral roentgenograms (Fig. 9, E) of the ankle made 3 years postoperatively showed solid fusion with the foot in 15 degrees equinus. The patient walked well in medium heels without pain or obvious limp.

FRACTURES Avulsion Fractures Avulsion fractures of the talus may occur at the superior surface of the neck or at the lateral or medial aspects of the body where ligamentous structures insert. Plantar flexion of the foot causes the former and inversion or eversion the latter. Fracture of the anterolateral articular surface of the posterior facet of the talus may occur from an avulsion force or more likely a compression of the os calcis against the facet produced by dorsiflexion and external rotation. 6

Fractures of the Posterior Process of the Talus The posterior process of the talus is formed by the smaller medial tubercle (tibial) and the larger lateral tubercle (fibular). The posterior portion of the deltoid ligament is attached to the medial tubercle and the posterior fasciculus of the lateral ligament of the ankle to the lateral tubercle. Either of these tubercles may be fractured as a result of an avulsion injury and, since the fracture is adjacent to the flexor hallucis longus and the articular surface of the tibia, rest or immobilization in plaster may be necessary. If the avulsed fracture is large and symptoms persist, removal of the fragment may be indicated.·· Ie, 16 Fractures involving the entire process are usually produced by a plantar flexion injury which impinges the process against the posterior margin of the tibia or the os calcis. There

DISLOCATIONS AND FRACTURES OF THE TALUS

95

is a complaint of pain in the region of the process, swelling on either side of the tendo achillis, and tenderness on pressure. The roentgenogram (Fig. 10, A) shows an irregular separation, which is in contrast to the smoothly separated secondary center of ossification known as the os trigonum seen in approximately 20 per cent of adults. The ossicle may be gradually separated as a result of repeated minor trauma such as that produced by kicking a football, which produces impingement of the process against the posterior margin of the tibia. The irregular fracture surfaces may become smooth as a result of nonunion and difficult to distinguish from a secondary center of ossification. 16 Clinical signs, irregularity of the separated surfaces, a comparative view of the opposite ankle and subsequent roentgenograms will aid in differentiating a fracture from the united secondary center of ossification, the os trigonum. CASE IX. A.M., a woman aged 53 years, was seen 2 weeks following reduction of a medial subtalar dislocation of the right foot. Anteroposterior and lateral view roentgenograms of the ankle showed an irregular separation of the posterior process of the talus (Fig. 10, A). A comparative view of the opposite ankle showed the process to be unseparated. The foot and ankle were immobilized in a short leg cast for 4 weeks, following which gradual weight bearing was begun. At the time of her last visit 5 months later, examination showed 20-degree restriction of lateral motion and roentgenograms (Fig. 10, B) showed that the process had united.

Marginal Fractures of the Superior Articular Surface of the Talus

Fractures involving either the medial or the lateral aspect of the superior articular surface of the talus have been variously designated flake fractures,t5 dome fractures 3 , 23 or transchondral fractures.! While all cases reported as osteochondritis dissecans of the talus do not give a historybf injury, the etiological factor is probably acute or repeated trauma. IS, 26 Inversion strain of the foot causes the lateral aspect of the talar dome to impinge on the fibula, resulting in a fracture. Plantar flexion may permit the fragment to turn upside down. 23 An oblique x-ray view and views with

Figure 10 (Case IX). A, Anteroposterior and lateral roentgenograms (on the left) of the right ankle of a 53 year old woman seen 2 weeks following a medial subtalar dislocation show a fracture of the posterior process of the talus with irregularity:'at 1the line of separation. B, Roentgenograms made 5 months later show union of the process.

96

JOHN

J.

FAHEY, JEROME

L.

MURPHY

the foot in dorsiflexion or plantar flexion may show a detached fragment that could not be demonstrated in anteroposterior and lateral views of the ankle.26 If the fractured fragment is of recent origin and in satisfactory position, the ankle is immobilized. Operation can be postponed if the lesion is of long standing and the patient is asymptomatic. If the fragment is displaced or turned over, excision is carried out. When the fragment is on the medial aspect of the talus posteriorly, and the fragment cannot be located through an anterolateral incision even after plantar flexion of the foot, it may be necessary to osteotomize the internal malleolus following the drilling of a hole to accommodate a screw in order to facilitate accurate reduction. Likewise, osteotomy of the fibula may be necessary in order to remove a fragment in the posterior aspect of the lateral margin.

Fractures of the Neck of the Talus Fracture through the neck of the talus results from a dorsiflexion injury by impingement on the anterior margin of the tibia. If there is no displacement, the foot should be immobilized for six or eight weeks in a neutral position and at a right angle. One must be on the alert for an associated subtalar dislocation of the body. If the body fragment is in equinus and if the foot is inverted or everted, it is likely that a subtalar dislocation of the body from the calcaneus is present. This is a second degree injury and requires a more severe force than that which produces an undisplaced fracture of the neck. 83 The talocalcaneal ligaments rupture and the distal fragment of the neck with the calcaneus and tarsal bones moves forward, inward or outward and dislocates the body and proximal neck fragment from the calcaneus. The body fragment then assumes an equinus position and the fracture surface contacts the superior surface of the calcaneus. If the dislocation is medially, traction is made on the inverted foot in plantar flexion in the direction of the deformity so that the distal fragment approximates the proximal fragment, following which the foot is brought into slight eversion and plantar flexion and immobilLed in a short leg cast for eight weeks. Redisplacement may occur as a result of changing the cast in a few weeks and bringing the foot into more dorsiflexion in order to obviate an equinus deformity. Where accurate closed reduction cannot be accomplished, open reduction should be performed and fixation accomplished by one or more heavy Kirschner wires. Associated fragments or imperfect reduction resulting in incongruity of the joint may require subtalar arthrodesis. The development of aseptic necrosis or degenerative changes may require fusion of the talus to the calcaneus or fusion to both the calcaneus and the tibia. If dorsiflexion force continues beyond that which produces a fracture of the neck with subtalar dislocation of the body of the talus, a complete dislocation of this fragment occurs. The posterior capsular structures are torn and the body of the talus is squeezed out of the ankle mortise and

·1

DISLOCATIONS AND FRACTUREs OF THE TALUS

97

completely dislocated posteromedially. It is guided by the posterior articular facet of the calcaneus so that it lies on the medial aspect of the calcaneus with the medial tubercle locked behind the sustentaculum tali and the fracture surface facing laterally and the inferior surface posteriorly, and it is held beneath the flexor tendons. 33 This injury requires prompt treatment because of the pressure on the skin which, if not relieved, will produce necrosis of the skin and infection. This fracture produces many formidable complications such as pressure on the neurovascular structures, associated fracture particularly of the internal malleolus, difficulty of reduction and the almost inevitable appearance of aseptic necrosis. An attempt at closed reduction by reproducing the mechanism which produced the fracture, namely, dorsiflexion of the foot and forward traction, eversion and plantar flexion, has been advocated." It is important not to injure the overlying skin by repeated attempts at closed reduction and, even if reduction is accomplished, it is not easy to maintain the fragments in a satisfactory position. If open reduction is performed, the fragments are fixed with pins or a staple. If reduction is not maintained accurately, a decision should be made to fuse one or both of the adjacent joints. Subtalar arthrodesis has been somewhat disappointing in revitalizing or preventing degenerative changes of the ankle resulting from aseptic necrosis and it is frequently necessary to perform a tibiotalocalcaneal fusion. In cases of imperfect reduction following fracture of the neck of the talus with subtalar dislocation associated with necrosis (Case XII, Fig. 13, A) and a good distal neck fragment, inclusion of the ununited neck fragment in the fusion insures against possible painful motion or deformity. The following case illustrates the management of an open fracture of the talar neck with subtalar dislocation. CASE X. M.R., a 64 year old man, was admitted to the hospital with an eversion deformity of the foot and an open wound on the inner side of the ankle as a result of a 3-foot fall from a ladder. Figure 11, A, shows a large open wound on the inner side of the ankle in which the flexor tendons, nerves and vessels were exposed. A roentgenogram (Fig. 11, B) showed a fracture of the neck of the talus with a lateral subtalar dislocation and a mild supination tilt of the talotibial joint. Under general anesthesia the patient was operated on 3 hours after the injury, using a tourniquet. The wound was debrided and cleansed with soap and water for 10 minutes and then thoroughly irrigated with saline solution. The knee was flexed and traction was made on the foot while it was brought medially and reduction of subtalar dislocation and fractured neck of the talus was accomplished. The fracture was fixed with a staple and the foot immobilized in 10 degrees equinus for 2 weeks at which time the stitches were removed and a new cast applied for 7 weeks, followed by active exercise and nonweight-bearing for another 6 weeks. Roentgenograxns (Fig. 11, C) made 2 years after reduction showed the fracture to be healed and there was no evidence of aseptic necrosis. The patient had normal dorsiflexion and plantar flexion but a loss of 5 degrees of eversion and he lacked 10 degrees of inversion on the involved side (Fig. 11, D). There was mild swelling but no pitting edema about the ankle. There was no discomfort or pain when he walked.

The closer the fracture of the neck of the talus approaches the body,

98

JOHN J.FAHEY, JEROME

L.

MURPHY

f I

Figure 11 (Case X). A, Photograph of the foot of a 64 year old man who fell from a ladder shows eversion of the foot and ankle and an open wound on the inner side of the ankle through which tendons and neurovascular structures were exposed. B, Roentgenograms of the ankle and foot show a fracture of the neck of the talus with lateral subtalar dislocation and a mild supination tilt of the talus at the ankle joint. C, Anteroposterior and lateral roentgenograms of the foot and ankle made 2 year!; ollowing operation showed union of the neck of the talus with no evidence of aseptic necrosis. D, Photographs made 2 years postoperatively show the range of motion. There was loss of only 5 degrees of eversion and 10 degrees of inversion. He was asymptomatic.

the more unfavorable the prognosis. Inversion or eversion at the ankle joint may, by splitting the talus in a sagittal plane, complicate a subtalar dislocation. CASE XI. J.B., a 27 year old man, was seen 3 hours after an automobile accident with a deformity of the right foot and ankle. The foot was in equinus and inverted and there was a prominence Over the anterolateral aspect of the ankle. There

DISLOCATIONS AND FRACTURES OF THE TALUS

99

was considerable swelling and discoloration about the ankle. Anteroposterior and lateral roentgenograms of the foot and ankle (Fig. 12, A) showed an incomplete pronation dislocation of the talus from the ankle mortise and a medial dislocation of the talus at the talocalcaneal and talonavicular joints. There was a large fragment from the dome and lateral wall of the talus which was displaced posteriorly. Closed manipulation under general anesthesia failed and the patient was prepared for operation. At operation an incision was made over the sinus tarsus region. The superior articular surface of the talus was found to be displaced anteriorly and in marked pronation. The talar articular facet had forced the fibular facet upward and later-

Figure 12 (Case XI). A and Al, A man 27 years old.was seen 3 hours following an automobile accident with a severe deformity of the ankle and foot. Anteroposterior and lateral roentgenograms of the ankle and foot show medial subtalar dislocation]at the talocalcaneal and taloscaphoid joints. The talus is severely pronated from the ankle mortise and there is a large displaced loose fragment from the dome of the talus displaced posteriorly. B, Roentgenograms of the ankle made 18 months following open reduction. There was some narrowing of the talocalcaneal joint but no evidence of aseptic necrosis could be demonstrated.

100

JOHN J. FAHEY, JEROME

L.

MURPHY

Figure 13 (Case XII). A, Anteroposterior and lateral roentgenograms of the left ankle of a 28 year old woman 5 months following treatment for a fracture dislocation involving the talus which was'incurred in an automobile accident. The fracture at the junction of the neck and body of the talus appeared to be incompletely united and the neck was displaced upward and medially from the body of the talus. The talocalcaneal joint appeared disrupted and the body had increased density indicating necrosis. B, Roentgenograms made 3 years following tibiocalcaneal fusion as well as fusion of the tibia to the neck of the talus showed consolidation. ally. By making traction in plantar flexion on the foot and pushing medially and posteriorly on the talus, reduction of the talocalcaneal, talonavicular and talotibial joints was accomplished; however, roentgenograms showed the loose fragment of the dome to be inaccurately reduced. An incision was made on the inner and posterior aspects of the ankle and the fragment was found to be considerably displaced. It was reduced and fixed with 2 Kirschner wires which were cut beneath the skin. The leg was immobilized in a cast at a right angle for 8 weeks, at which time the wires were removed and a new cast applied for 1 month. Roentgenograms made 18 months after reduction (Fig. 12, B) showed union of the fragment and no increased density in the nonoverlapping areas on the lateral view. There was some narrowing of the talocalcaneal joint space. The patient had some discomfort below the internal and external malleoli with weather changes and with excessive activity.

A fracture-dislocation through the body of the talus has a less favorable prognosis than a fracture of the talar neck associated with dislocation.

DISLOCATIONS AND FRACTURES OF THE TALUS

101

A plantar flexion injury may produce a fracture of the posterior portion of the talar body.2 If a fracture at the junction of the neck and body depresses the talar body, a step deformity is produced. The following case describes the management of such an injury associated with medial subtalar dislocation and aseptic necrosis of the body of the talus. CASE XII. A.P., a 28 year old woman, was seen because of generalized swelling about the ankle, pain and inability to walk without crutches. Five months previously she incurred a fracture of the talus in an automobile accident. Following manipulation and immobilization in a short leg cast for 2 months, she received physical therapy and for the past month had borne some weight but because of pain was unable to walk unassisted. The foot was held in equinovarus position and there was considerable swelling about the ankle and foot. Anteroposterior and lateral roentgenograms (Fig. 13, A) of the ankle showed an incompletely united fracture at the junction of the neck and body with upward displacement of the neck and medial subtatlar dislocation. The body of the talus was in the ankle mortise and there was medial displacement of the neck of the talus, calcaneus and foot from the body of the talus. There was increased density of the entire body of the talus even in the areas not overlapped by the fibula and internal malleolus of the tibia, indicative of aseptic necrosis. A tibiotalocalcaneal fusion was carried out through an anterolateral approach in which the talotibial and talocalcaneal joint surfaces were resected. A lateral wedge was removed from the subtalar joint in order to correct the varus deformity of the foot. A tibial graft was removed from the anterolateral aspect of the tibia and cut into two portions. One portion was driven in a slot made in the tibia and in the neck fragment. The other portion was used to bridge the tibiotalocalcaneal joints. Cancellous bone removed from the lower tibia was used to supplement the tibial grafts. The patient was immobilized in a long leg cast with the foot in 15 degrees of equinus and the knee flexed 20 degrees. Two weeks after the operation the cast and stitches were removed and a new cast applied. Immobilization was continued for 4 months followed by ambulation in a short leg brace with a foot plate for 2 months. Three years following the operation, roentgenograms (Fig. 13, B) showed union of the talotibial and talocalcaneal joints. Examination at that time revealed 15 degrees of equinus and 10 degrees of midtarsal motion. Walking was difficult going down stairs and when she was barefooted. With high heels, she walked without pain or limp and had a normal gait.

REFERENCES 1. J3erndt, A. L. and Harty, M.: Transchondral fractures (osteochondritis dissecans) of the talus. J. Bone & Joint Surg. 41A: 988-1020 (Sept.) 1959. 2. Bohler, Lorenz: The Treatment of Fractures, Vol. III. 5th Ed. New York & London, Grune & Stratton, 1958. 3. Coitart, W. D.: Aviator's astragalus. J. Bone & Joint Surg. 34B: 545-566 (Nov.) 1952. 4. Conwell, H. E. and Alldredge, R. H.: Complete compound dislocation (internal lateral) of the ankle joint without fracture with primary healing. J.A.M.A. 108: 2035-2036 (June) 1937. 5. Dimon, J. H., III: Isolated displaced fracture of the posterior facet of the talus. J. Bone & Joint Surg. 43A: 275-281 (March) 1961. 6. Fonda, M. P.: Dislocation of the tibiotalar joint without fracture. J. Bone & Joint Surg. 34A: 662-664 (July) 1952. 7. Haines, Charles: Compound dislocation of the tibiotalar joint without fracture and without separation. J. Bone & Joint Surg. Sl: 205 (Jan.) 1939.

102

JOHN J. FAHEY, JEROME

L.

MURPHY

8. Halburton, R. A., Sullivan, C. R., Kelly, P. J. and Peterson, L. F.: The extra.osseous and intra-osseous blood supply of the talus. J. Bone & Joint Surg. 40A: 1115-1120 (Oct.) 1958. 9. Jacobs, Philip: Chronic progressive dislocation of the tala-navicular joint. J. Bone & Joint Surg. 46B: 214-217 (May) 1964. 10. Kelly, P. J. and Peterson, L. F. A.: Compound dislocation of the ankle without fracture. Am. J. Surg. 108: 170-172, 1962. 11. Larsen, R. L., Sullivan, C. R. and Jane.q , J. M.: Trauma surgery, and circulation of the talus-What are the risks of avascular necrosis? J. Trauma 1: 13 (Jan.) 1961. 12. Leitner, Baldo: Obstacles to reduction in subtalar dislocations. J. Bone & Joint Surg. 86A: 299-306 (April) 1954. 13. Leitner, Baldo: Mechanism of total dislocation of the talus. J. Bone & Joint Surg. 87A: 89-95 (Jan.) 1955. 14. Lewin, Philip: The Foot and Ankle. 4th Ed. Philadelphia, Lea & Fehiger, 1959. 15. Marks, K. L.: Flake fracture of the talus, progressing to osteochondritis dissecans. J. Bone & Joint Surg. 84B: 90-92 (Feb.) 1952. 16. McDougall, A.: The os trigonum. Brit. J. Bone & Joint Surg. 87B: 257-265 (May) 1955. 17. McKeever, F. M. L.: Fracture of the neck of the astragalus. Arch. Surg. 46: 720735,1943. 18. McLaughlin, H. L.: Trauma. Philadelphia, W. B. Saunders Co., 1959, pp. 307-321. 19. Mindell, E. R.: Late results of injuries to the talus. J. Bone & Joint Surg. 45A: 221-245 (March) 1953. 20. Mitchell, J. I.: Total dislocation of the talus. J. Bone & Joint Surg. 18: 212-214 (Jan.) 1936. 21. Mulroy, R. D.: The tibialis posterior tendon as an obstacle to reduction of a lateral anterior subtalar dislocation. J. Bone & Joint Surg. 87A: 859-863 (July) 1955. 22. Newcomb, W. F. and Brav, E. A.: Complete dislocation of the talus. J. Bone & Joint Surg. 80A: 872-874 (Oct.) 1948. 23. Nisbet, N. W.: Dome fracture of the talus. J. Bone & Joint Surg. 86B: 244-246, (May) 1954. 24. North, J. P.: Compound dislocation of the talus without malleolar fracture. J. Bone & Joint Surg. so: 458-460 (April) 1938. 25. Pennal, G. F.: Fractures of the talus. Clin. Orthopaedics and Related Research, No. 30, 1963, pp. 53-63. 26. Ray, R. B. and Coughlin, E. J.: Osteochondritis dissecans of the talus. J. Bone & Joint Surg. 19: 697-706 (July) 1947. 27. Sewell, R. B. S.: A study of the astragalus. J. Anat. & Physiol., Part I, 88:233-247, Part III, 89: 74-88, 1904. 28. Shands, A. R., Jr.: Incidence of subastragaloid dislocation of the foot with a report of one case of the inward type. J. Bone & Joint Surg. 10: 306-313 (April) 1928. 29. Sloane, D. and Coutts, M. B.: Traumatic dislocation of the ankle without fracture. J. Bone & Joint Surg. 19: 1110-1112 (Oct.) 1937. 30. Smith, Hugh: Subastragalar dislocation-a report of seven cases. J. Bone & Joint Surg. 19: 373-380 (April) 1937. 31. Sneed, W. L.: The astragalus-a case of dislocation, excision and replacement. An attempt to demonstrate the circulation in the bone. J. Bone & Joint Surg. 1: 384 (April) 1925. 32. Sullivan, C. R. and Jackson, S. C.: Fracture dislocations of the astragalus in children: A clinical study and survey of the literature. Acta orthop. scandinav. B1: Fasc. 4, 1958. 33. Watson-Jones, Sir Reginald: Fractures and Joint Injuries, Vol. II. 4th Ed. Baltimore, Williams & Wilkins Co., 1960, pp. 878-900. 34. Wilson, M. J., Michele, A. A. and Jacobson, E. W.: Ankle dislocations without fracture. J. Bone & Joint Surg. 11: 198-204 (Jan.) 1939. 35. Woods, R. S.: Irreducible dislocation of the ankle joint. Brit. J. Surg. 19: 359-360, 1942. 1791 West Howard Street Chicago, Illinois 60626 (Dr. Fahey)