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Isolated posterior malleolar fractures
Isolated Posterior Malleolar Fractures L. RICHARD BOGGS, MD Three cases are presented of isolated fractures of the posterior malleolus as seen in an emergency department. Isolated posterior malleolar fractures are associated with compression and/or plantar flexion injuries of the foot. The Lauge-Hansen classification of ankle fractures, and its derivatives, do not include these injuries because of their rarity. They should be considered in all cases of ankle injury. (Am J Emerg Med 1986;4:334-336)
examination revealed a nondisplaced avulsion of the posterior malleolar lip without involvement of the articular surface. An orthopedic consult was obtained, and the patient was discharged with an ace wrap in place, crutches, and instructions not to bear weight. She was seen in the orthopedist’s office the following day and placed in a short leg walking cast for six weeks with an uneventful recovery.
Case 2 Injuries to the ankle are among the most common complaints presenting to an emergency department, and fractures of the ankle are among the most common fractures seen by the emergency physician. Fractures of the posterior malleolus frequently are associated with other injuries of the ankle, but are comparatively rare, isolated fractures.1,2 They can be relatively pain-free, allowing the patient to ambulate with little difficulty except for minor discomfort.2 These injuries, if sought, are usually not difficult to detect on physical and/or radiological examination of the ankle. Therapy is based on the presence of displacement and the percentage of the articular surface involved.2,3 If not discovered and treated appropriately, these injuries have a high incidence of complications.?q4 CASE REPORTS
A 13-year-old girl slid into a base with her left foot extended and injured her ankle with an unknown mechanism of action. The patient complained of severe pain in the ankle and inability to bear weight. The physical examination was significant for swelling and tenderness anterolaterally. with a normal neurovascular examination results. Radiological examination revealed a Salter-type four fracture of the posterior malleolus with approximately 3 mm of displacement involving approximately 25% of the articular surface (Fig. 1). Orthopedic consultation was obtained. and attempted closed reduction was unsuccessful. She was placed in a short leg cast and seen in the clinic the following day. At that time, a CT scan and conventional tomograms were obtained and revealed widening of the physis. The patient underwent open reduction with internal fixation five days after injury. On follow-up three months later, radiological examination revealed no evidence of closure of the physis and an intact mortice.
Case 1
Case 3
A 27-year-old woman arrived by ambulance after falling down a flight of stairs. The only complaint was severe pain in her left ankle and inability to bear weight. Hyperdorsiflexion of the ankle was described by the patient as the mechanism of injury. Past medical history was significant for multiple prior “sprains” of the same ankle. The physical examination revealed marked diffuse swelling about the ankle with no ecchymosis. There was marked tenderness in the posterior tibia1 area only. The pain in the ankle was increased by dorsiflexing the foot. Neurovascularly, the foot was thought to be intact. Radiological
A 4 l-year-old woman jumped from a slowly moving truck and landed on her feet. She presented to the emergency department complaining of bilateral ankle and foot pain. Results of the physical examination were significant for diffuse ankle tenderness and swelling on the left and swelling and tenderness on the lateral aspect of the right foot and ankle. Radiological examination revealed a posterior malleolar fracture on the left involving approximately a third of the articular surface without displacement (Fig. 2), and an avulsion fracture of the lateral aspect of the talus on the right. Orthopedic consultation was obtained, and the patient was placed in bilateral short leg casts. Weightbearing was allowed on the right. On re-evaluation the following day. it was decided that reduction was maintained and the patient was treated with a short-leg walking casts for six weeks without sequelae.
From the Milton gency Medicine, Manuscript 1985.
S. Hershey Medical Center, Hershey, Pennsylvania.
received
December
Division
2, 1985; accepted
of Emer-
December
3,
Address reprint requests to Dr. Boggs: Division of Emergency Medicine, Milton S. Hershey Medical Center, P.O. Box 850, Hershey, PA 17033. Key Words: Fracture, subluxation. 0735-6757186 $00.00 334
Lauge-Hansen,
+ .25
posterior
malleolus,
talar
DISCUSSION The history of a posterior malleolar fracture is frequently one in which the patient has no idea of the exact mechanism, which is common with most ankle injuries.5 The patients are frequently young (21-44 years old), and the injury is usually precipitated by a
BOGGS n ISOLATED
POSTERIOR
MALLEOLAR
FRACTURES
stumble or fall.’ It is also not unusual for these patients to be able to bear weight after the injury with little difficulty.* The results of the physical examination are usually only significant for tenderness in the area about the achilles tendon,* but as with all ankle injuries, the proximal fibula must be palpated to rule out a Maisonneuve fracture. Radiological examination reveals the fracture only on the lateral view, but that view is not completely reliable. A ‘ “poor” lateral’ has been suggested when the fracture is clinically suspected but is not visible on routine radiographs. The overlap of the tibia and the fibula on the true lateral may obscure the fracture. This overlap may be avoided by externally rotating the foot and thereby placing the fibula posterior to the posterior lip of the tibia.’ The common classification of ankle injuries is based on the system developed by Lauge-Hansen in 1950.6 His system is based on the position of the foot at the
FIGURE 2. Salter type four fracture of the posterior malleolus is shown with approximately 3 mm of displacement involving approximately 25% of the articular surface.
FIGURE 1. Posterior malleolar fracture on the left is shown involving approximately a third of the articular surface without displacement.
time of injury and the direction of the deforming force on the foot. There are four major types of injury within the classification system, and stages within each type. The four types are: 1) supination-adduction; 2) supination-eversion; 3) pronation-abduction; and 4) pronation-eversion. The first word relates the position of the foot, while the second denotes the direction of the injuring force. Fractures of the posterior malleolus are found as associated injuries in the supination-eversion, the pronation-eversion, and the pronation-abduction injuries.‘*2J,6 In Lauge-Hansen’s series of patients, there were no cases of isolated fractures of the posterior malleolus mentioned,*T6 and there have been no reports in the literature to indicate that they are a common injury. Therefore, they are not included in the Lauge-Hansen system of ankle injuries or derivatives of it. l They are most frequently seen after hyper335
AMERICAN
JOURNAL
OF EMERGENCY
MEDICINE
m Voiume
4, Number
plantar flexion injuries and/or compression of the posterior malleolus by the talus.* Those injuries without significant compression force usually involve only the posterior tibia1 lip with or without involvement of a small portion of the articular surface. Those with significant compression forces usually involve a larger portion of the articular surface.Z Another classification system to consider uses the talus as the reference point and is based on forces directed medially, laterally, or vertically. This system takes into account the mechanism of isolated posterior malleolar fractures. Consideration of three factors is involved in describing the injury: 1) the position of the foot at the time of injury; 2) the direction of the injuring forces that displace the talus; and 3) the intensity of the injuring force and the resistance of the supporting structures. Class A injuries involve forces that displace the talus laterally; Class B injuries result from forces that medially displace the talus; and Class C resulting from axial compression forces. AI1 these classes have groups and subgroups. but the major group of interest here is Class C, Group 1B. This group is based on vertical compression forces applied to a plantar flexed foot that results in a posterior tibia1 fracture.*-lo Treatment is determined by the percentage of the articular surface involved and whether the fracture is displaced. If less than 10% of the articular surface is involved, there is little incidence of posterior talar subluxation. If greater than 25% of the articular surface is involved, there is a 100% incidence of posterior talar subluxation and/or post-traumatic arthritis if reduction is not obtained. If between 10 and 25% of the articular surface is involved, there is a 20% incidence of posterior subluxation. It is therefore recommended that all fractures involving 25% or greater of the articular surface undergo open reduction and internal fixation.3 The incidence of post-traumatic arthritis is markedly reduced after internal fixation in these injuriesS2JJ1 Undisplaced isolated fractures of the posterior tibia may be treated in a short leg cast.* The cases presented include fractures that required closed reduction and those that required open reduction and internal fixation. The first case presented describes a mechanism of action that is not associated with isolated posterior malleolar fractures. The in-
336
4 m July 1986
volvement of the physis in the fragment in the second case is unusual but led to no adverse sequelae as of three months after the repair. The third case illustrates a fracture involving approximately a third of the articular surface but without displacement. This was successfully treated with closed reduction. The isolated posterior malleolar fracture is an uncommon occurrence in which the patient presents to the physician with minimal complaints. It can easily be overlooked on the physical examination if the posterior malleolar area is not palpated because of a low index of suspicion on the examiner’s part. The radiological examination may also be misleading secondary to overlap of the tibia and fibula. If clinically indicated, the “poor” lateral should be obtained. If these injuries are not discovered, or involve more than 25% of the articular surface, there is a high incidence of complications, especially if there is displacement. The author thanks Thomas Martin, MD, for hts constructive criticisms in the preparation of this paper, and Donna Renzel for her help in preparing the manuscript.
REFERENCES 1. Yde J. The Lauge-Hansen classification of malleolar fractures. Acta Orthop Stand 1980;51 :I81 -192. 2. Wilson FC. Fractures and dislocations of the ankle. In Rockwood CA, Green DP (eds). Fractures in Adults. Philadelphia: J. P. Lippincott Co., 1984:1665-1701. 3. McLaughlin HL, Ryder CT Jr. Open reduction and internal fixation for fractures of the tibia and fibula. Surg Clin North Am 1949;29:1523-1534. 4. Wheelhouse WW, Rosenthal RE. Unstable ankle fractures: Comparison of closed and open treatment. South Med J 1980;73:45-50. 5. Arimoto HK, Forrester DM. Classification of ankle fractures: An algorithm. Am J Radio1 1980;135:1057-1063. 6. Lauge-Hansen N. Fractures of the ankle: Combined experimental-surgical and experimental-roentgenologic investigations. Arch Surg 1950;60:957-985. 7. Mandell J. Isolated fractures of the posterior tibia1 lip at the
8. 9. 10.
11.
ankle as demonstrated by an additional projection, “poor” lateral view. Radiology 1971;101:319-322. Kleiger BMD. Mechanisms of ankle injury. Orthop North Am 1974;5:127-146. Kleiger BMD. The mechanism of ankle injuries. J Bone Surg 1956;38A:59-70. Simon R. Ankle and foot. In Rosen P (ed): Emergency cine: Concepts and Clinical Practice. St. Louis: Mosby Co., 1983:624-646. Miller AJ. Posterior malleolar fractures. J Bone Joint 1974;568:508-512.
the Clin Joint MediC. V. Surg
examination revealed a nondisplaced avulsion of the posterior malleolar lip without involvement of the articular surface. An orthopedic consult was obtained, and the patient was discharged with an ace wrap in place, crutches, and instructions not to bear weight. She was seen in the orthopedist’s office the following day and placed in a short leg walking cast for six weeks with an uneventful recovery.
Case 2 Injuries to the ankle are among the most common complaints presenting to an emergency department, and fractures of the ankle are among the most common fractures seen by the emergency physician. Fractures of the posterior malleolus frequently are associated with other injuries of the ankle, but are comparatively rare, isolated fractures.1,2 They can be relatively pain-free, allowing the patient to ambulate with little difficulty except for minor discomfort.2 These injuries, if sought, are usually not difficult to detect on physical and/or radiological examination of the ankle. Therapy is based on the presence of displacement and the percentage of the articular surface involved.2,3 If not discovered and treated appropriately, these injuries have a high incidence of complications.?q4 CASE REPORTS
A 13-year-old girl slid into a base with her left foot extended and injured her ankle with an unknown mechanism of action. The patient complained of severe pain in the ankle and inability to bear weight. The physical examination was significant for swelling and tenderness anterolaterally. with a normal neurovascular examination results. Radiological examination revealed a Salter-type four fracture of the posterior malleolus with approximately 3 mm of displacement involving approximately 25% of the articular surface (Fig. 1). Orthopedic consultation was obtained. and attempted closed reduction was unsuccessful. She was placed in a short leg cast and seen in the clinic the following day. At that time, a CT scan and conventional tomograms were obtained and revealed widening of the physis. The patient underwent open reduction with internal fixation five days after injury. On follow-up three months later, radiological examination revealed no evidence of closure of the physis and an intact mortice.
Case 1
Case 3
A 27-year-old woman arrived by ambulance after falling down a flight of stairs. The only complaint was severe pain in her left ankle and inability to bear weight. Hyperdorsiflexion of the ankle was described by the patient as the mechanism of injury. Past medical history was significant for multiple prior “sprains” of the same ankle. The physical examination revealed marked diffuse swelling about the ankle with no ecchymosis. There was marked tenderness in the posterior tibia1 area only. The pain in the ankle was increased by dorsiflexing the foot. Neurovascularly, the foot was thought to be intact. Radiological
A 4 l-year-old woman jumped from a slowly moving truck and landed on her feet. She presented to the emergency department complaining of bilateral ankle and foot pain. Results of the physical examination were significant for diffuse ankle tenderness and swelling on the left and swelling and tenderness on the lateral aspect of the right foot and ankle. Radiological examination revealed a posterior malleolar fracture on the left involving approximately a third of the articular surface without displacement (Fig. 2), and an avulsion fracture of the lateral aspect of the talus on the right. Orthopedic consultation was obtained, and the patient was placed in bilateral short leg casts. Weightbearing was allowed on the right. On re-evaluation the following day. it was decided that reduction was maintained and the patient was treated with a short-leg walking casts for six weeks without sequelae.
From the Milton gency Medicine, Manuscript 1985.
S. Hershey Medical Center, Hershey, Pennsylvania.
received
December
Division
2, 1985; accepted
of Emer-
December
3,
Address reprint requests to Dr. Boggs: Division of Emergency Medicine, Milton S. Hershey Medical Center, P.O. Box 850, Hershey, PA 17033. Key Words: Fracture, subluxation. 0735-6757186 $00.00 334
Lauge-Hansen,
+ .25
posterior
malleolus,
talar
DISCUSSION The history of a posterior malleolar fracture is frequently one in which the patient has no idea of the exact mechanism, which is common with most ankle injuries.5 The patients are frequently young (21-44 years old), and the injury is usually precipitated by a
BOGGS n ISOLATED
POSTERIOR
MALLEOLAR
FRACTURES
stumble or fall.’ It is also not unusual for these patients to be able to bear weight after the injury with little difficulty.* The results of the physical examination are usually only significant for tenderness in the area about the achilles tendon,* but as with all ankle injuries, the proximal fibula must be palpated to rule out a Maisonneuve fracture. Radiological examination reveals the fracture only on the lateral view, but that view is not completely reliable. A ‘ “poor” lateral’ has been suggested when the fracture is clinically suspected but is not visible on routine radiographs. The overlap of the tibia and the fibula on the true lateral may obscure the fracture. This overlap may be avoided by externally rotating the foot and thereby placing the fibula posterior to the posterior lip of the tibia.’ The common classification of ankle injuries is based on the system developed by Lauge-Hansen in 1950.6 His system is based on the position of the foot at the
FIGURE 2. Salter type four fracture of the posterior malleolus is shown with approximately 3 mm of displacement involving approximately 25% of the articular surface.
FIGURE 1. Posterior malleolar fracture on the left is shown involving approximately a third of the articular surface without displacement.
time of injury and the direction of the deforming force on the foot. There are four major types of injury within the classification system, and stages within each type. The four types are: 1) supination-adduction; 2) supination-eversion; 3) pronation-abduction; and 4) pronation-eversion. The first word relates the position of the foot, while the second denotes the direction of the injuring force. Fractures of the posterior malleolus are found as associated injuries in the supination-eversion, the pronation-eversion, and the pronation-abduction injuries.‘*2J,6 In Lauge-Hansen’s series of patients, there were no cases of isolated fractures of the posterior malleolus mentioned,*T6 and there have been no reports in the literature to indicate that they are a common injury. Therefore, they are not included in the Lauge-Hansen system of ankle injuries or derivatives of it. l They are most frequently seen after hyper335
AMERICAN
JOURNAL
OF EMERGENCY
MEDICINE
m Voiume
4, Number
plantar flexion injuries and/or compression of the posterior malleolus by the talus.* Those injuries without significant compression force usually involve only the posterior tibia1 lip with or without involvement of a small portion of the articular surface. Those with significant compression forces usually involve a larger portion of the articular surface.Z Another classification system to consider uses the talus as the reference point and is based on forces directed medially, laterally, or vertically. This system takes into account the mechanism of isolated posterior malleolar fractures. Consideration of three factors is involved in describing the injury: 1) the position of the foot at the time of injury; 2) the direction of the injuring forces that displace the talus; and 3) the intensity of the injuring force and the resistance of the supporting structures. Class A injuries involve forces that displace the talus laterally; Class B injuries result from forces that medially displace the talus; and Class C resulting from axial compression forces. AI1 these classes have groups and subgroups. but the major group of interest here is Class C, Group 1B. This group is based on vertical compression forces applied to a plantar flexed foot that results in a posterior tibia1 fracture.*-lo Treatment is determined by the percentage of the articular surface involved and whether the fracture is displaced. If less than 10% of the articular surface is involved, there is little incidence of posterior talar subluxation. If greater than 25% of the articular surface is involved, there is a 100% incidence of posterior talar subluxation and/or post-traumatic arthritis if reduction is not obtained. If between 10 and 25% of the articular surface is involved, there is a 20% incidence of posterior subluxation. It is therefore recommended that all fractures involving 25% or greater of the articular surface undergo open reduction and internal fixation.3 The incidence of post-traumatic arthritis is markedly reduced after internal fixation in these injuriesS2JJ1 Undisplaced isolated fractures of the posterior tibia may be treated in a short leg cast.* The cases presented include fractures that required closed reduction and those that required open reduction and internal fixation. The first case presented describes a mechanism of action that is not associated with isolated posterior malleolar fractures. The in-
336
4 m July 1986
volvement of the physis in the fragment in the second case is unusual but led to no adverse sequelae as of three months after the repair. The third case illustrates a fracture involving approximately a third of the articular surface but without displacement. This was successfully treated with closed reduction. The isolated posterior malleolar fracture is an uncommon occurrence in which the patient presents to the physician with minimal complaints. It can easily be overlooked on the physical examination if the posterior malleolar area is not palpated because of a low index of suspicion on the examiner’s part. The radiological examination may also be misleading secondary to overlap of the tibia and fibula. If clinically indicated, the “poor” lateral should be obtained. If these injuries are not discovered, or involve more than 25% of the articular surface, there is a high incidence of complications, especially if there is displacement. The author thanks Thomas Martin, MD, for hts constructive criticisms in the preparation of this paper, and Donna Renzel for her help in preparing the manuscript.
REFERENCES 1. Yde J. The Lauge-Hansen classification of malleolar fractures. Acta Orthop Stand 1980;51 :I81 -192. 2. Wilson FC. Fractures and dislocations of the ankle. In Rockwood CA, Green DP (eds). Fractures in Adults. Philadelphia: J. P. Lippincott Co., 1984:1665-1701. 3. McLaughlin HL, Ryder CT Jr. Open reduction and internal fixation for fractures of the tibia and fibula. Surg Clin North Am 1949;29:1523-1534. 4. Wheelhouse WW, Rosenthal RE. Unstable ankle fractures: Comparison of closed and open treatment. South Med J 1980;73:45-50. 5. Arimoto HK, Forrester DM. Classification of ankle fractures: An algorithm. Am J Radio1 1980;135:1057-1063. 6. Lauge-Hansen N. Fractures of the ankle: Combined experimental-surgical and experimental-roentgenologic investigations. Arch Surg 1950;60:957-985. 7. Mandell J. Isolated fractures of the posterior tibia1 lip at the
8. 9. 10.
11.
ankle as demonstrated by an additional projection, “poor” lateral view. Radiology 1971;101:319-322. Kleiger BMD. Mechanisms of ankle injury. Orthop North Am 1974;5:127-146. Kleiger BMD. The mechanism of ankle injuries. J Bone Surg 1956;38A:59-70. Simon R. Ankle and foot. In Rosen P (ed): Emergency cine: Concepts and Clinical Practice. St. Louis: Mosby Co., 1983:624-646. Miller AJ. Posterior malleolar fractures. J Bone Joint 1974;568:508-512.
the Clin Joint MediC. V. Surg