FROM THE DEPARTMENTS OFORTHOPAEDICS (DIRECTOR: PROF. G. BAUER) AND DIAGNOSTIC RADIOLOGY II (DIRECTOR: PROF. O. "ORMAN), UNIVERSITY HOSPITAL, S-221 85 LUND, SWEDEN.
ANTERIOR INSTABILITY IN THE ANKLE JOINT FOLLOWING ACUTE LATERAL SPRAIN A. LINDSTRAND and W. MORTENSSON
The lateral ligaments of the ankle are of the utmost importance for the stability of the joint. The anterior talofibular ligament (in the following called the anterior ligament) is often ruptured in ankle sprains (BROSTROM 1964, CEDELL 1967). Persistent discomfort after ankle sprain is often due to defective healing of the ligament (BROSTROM 1966). Opinions differ about the treatment of the acute rupture. This uncertainty, at least partly, reflects the lack of precise diagnostic criteria for this ligament lesion. When avulsion of the attachment of the ligament to the bone has occurred, the diagnosis is usually made directly by radiographic demonstration of the bone fragment. However, the rupture usually occurs solely in the ligament tissue itself (BROSTROM 1964). In that event, the diagnosis must be based on indirect evidence, either the demonstration of displacement of the talus or the leakage of contrast medium from the joint at arthrography. After division of the anterior ligament of corpses, the talus may be dislodged anteriorly (DEHNE 1933, ANDERSON et coli. 1952, CASTAING & DELPLACE 1972). Under clinical conditions, the displacement of the talus, in an acute rupture, is usually blocked by muscle defence evoked by pain but may be demonstrated by provocation. This fact has been used to diagnose the rupture at clinical examination (LINDSTRAND 1976) and at radiography (ANDERSON et coil. 1952, RUTH 1961, COUTTS & WOODWARD 1965, CASTAING & DELPLACE 1972, REICHEN & MARTI 1974), usually only Submitted for publication 10 March 1976. Acta Radiologica Diagnosis 18 (1977) Fasc. 5 September
34- 775845
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
529
530
A. LINDSTRAND AND W. MORTENSSON
Fig. 1. Equipment for examination of anterior stability of the ankle joint. The patient's leg is raised, supported at the heel, and rotated inwards about 30°. A sandbag hangs on the lower leg to provoke displacement. The projection is checked by fluoroscopy.
single cases are reported, and the diagnostic value of radiography has not been adequately established. The present report deals with the diagnosis of acute rupture of the anterior ligament based on provoked anterior displacement of the talus demonstrated by radiography. The purpose was to compare the degree of anterior displacement of the talus, as demonstrated by radiography with the actual condition of the ligament, as observed at operation, and to define a suitable procedure for the radiography. Preliminary results were reported previously (MORTENSSON & LINDSTRAND 1974). Material
The material consisted of 68 patients, 42 men and 26 women, aged 14 to 47, mean age 26 years, with an acute ankle sprain. All had a history of indirect violence, usually a supination trauma. Only those patients were included who were considered to have anterior ligament rupture at physical examination (for a detailed description, see LINDSTRAND 1976). No patients with fractures or signs of injured medial collateral ligaments were included. In all the 68 patients, the surgical exploration was performed because of signs of ligament lesions, irrespective of the results of radiography. Radiography
The examination was usually performed within 3 days after the injury. Attempts were made to displace the talus anteriorly with the patient supine, his leg raised,
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
ANTERIOR INSTABILITY IN THE ANKLE JOINT
a
b
c
d
531
Fig. 2. Joint surfaces of tibia and talus run parallel and describe parts of concentric circles (a, c). This symmetry disappears when the talus is displaced anteriorly (b, d). With the aid of the transparent graph (Fig. 3), a line is drawn through the middle of the lower tibia and the centre of the 'tibial circle' (c). Another line paralleling this is drawn through the centre of the 'talar circle' (d). The perpendicular distance between these two lines indicates the anterior displacement of the talus. The displacement index is obtained by dividing this distance by the sagittal length of the tibial joint surface (all measures in mm) and multiplying by 1 000. The displacement index is 275 in the case reproduced.
supported at the heel, and rotated inwards about 30°, and the ankle joint slightly plantar-flexed (Fig. I). The need for complete muscle relaxation was explained to the patient. After the position of the joint had been checked by fluoroscopy, lateral projections were obtained. The correct projection was defined as one in which the joint surface of the talar trochlea was projected tangentially (Fig. 2 a). Six exposures were made according to the following schedule. The weight of the leg was allowed to act on the joint for about one minute, and one exposure was made. An additional provocation effort was then made by application of a sandbag weighing 4 kg to the lower leg. The effect was registered by two exposures after half a minute and two minutes, respectively. The same procedure was repeated after the area round the ligament had been locally anaesthetized by 6 to 10 ml carbocain 1 % without vasoconstrictor agents. For comparison, the uninjured ankle was also examined at the same time, but without anaesthesia, except in the first patients of the series. All films not fulfilling the demands according to the definition of a true lateral projection were excluded. The patients with a complete examination schedule were used for the analysis of the influence of variations of the procedure on the results.
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
532
A. LINDSTRAND AND W. MORTENSSON
Fig. 3. Transparent graph used to measure talar displacement. The film is placed on the transparent graph so that the tibial joint surface covers the arc corresponding in size and so that the elongated radius passes through the middle of the lower tibia. This line is transferred to the film which is then placed so that the talar trochlea covers a corresponding arc and the elongated radius parallels the first line. This line is also drawn on the film and the distance between the two lines represents the anterior displacement of the talus (see also Fig. 2 b, d).
The total material was used to evaluate the sensitivity and specificity of the method and its diagnostic value. In addition, 11 patients were subjected to radiography in epidural anaesthesia in connection with the operation; in 8 of these the uninjured ankle was also examined at the same time. Displacement index: In lateral projection, the joint surfaces of the tibia and the talus may be considered to describe arcs of concentric circles (Fig. 2 a, c). This congruity disappears when the talus is displaced (Fig. 2 b, d). The distance between the centres of these two circles indicates the degree of anterior displacement of the talus (Fig. 2 d). A transparent graph was used for the calculation (Fig. 3). Correction for varying geometric enlargement was made by dividing the measured anterior displaceTable 1 The condition of the anterior talofibular ligament at operation for acute ankle sprain
Group 1 Group 2 Group 3
Normal No rupture but abnormal macroscopic appearance Acute total rupture
11 5 52*
* Tn 5 patients combined with a complete and in 5 with an incomplete acute rupture of the ca\caneofibular ligament.
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
533
ANTERIOR INSTABILITY IN THE ANKLE JOINT
Table 2 Anterior displacement of the talus in ankles without rupture of the anterior talofibular ligament. All had recently sustained ankle sprains and had clinically suggested ruptures. At operation the ligament was found to be normal in 11 (Group I) and to have abnormal appearance in five (Group 2). Not all the ankles were examined according to the complete examination schedule. The degree of anterior displacement was expressed in an index
Group 2
Group 1 Range
Mean SO n
Range
0--63 0-65 0-85
15 33 45
21 29 43
9 6 3
0-50 0--233 23-132
0-103 0-87 0-205
37 49 76
41 55 60
8 7 9
26-200 100--196 67-125
Mean SO
n
33 90 78
28 101 76
3 4 2
86 159 99
78 68 30
4 3 3
A. Without local anaesthesia I. No additional provocation 2. Additional provocation 1/2 min 3. Additional provocation 2 min B. With local anaesthesia I. No additional provocation 2. Additional provocation 1/2 min 3. Additional provocation 2 min Significance of the differences AI v. A3 not significant HI v. B3 not significant AI v. 82 not significant
A I v. A3 not significant HI v. 83 not significant AI v. HI not significant
ment by the sagittal length of the tibial joint surface, the quotient being multiplied by I 000. The result was referred to as the displacement index. No correction was made for the various sizes of the tibial joint surface. Only the anterior displacement was measured; the concomitant medial rotation and the distal displacement of the talus were not considered. Statistical methods In constructing Table 3, differences between displacement index within the groups were estimated by the t-test for paired observations. Otherwise, quantitative differences were estimated by conventional t-test for unpaired observations. Confidence intervals for differences were made in the way described in Geigy's Scientific Tables (1971). In the text a 95 per cent confidence interval is given within brackets following the percentage number.
Results
Clinical results. At exploration, an acute rupture of the anterior talofibular ligament was most frequent. An additional partial or total rupture of the calcaneofibular ligament was found in one fifth of these cases. Two had an isolated rupture of the anterior tibiofibular ligament. If no fresh ligament rupture existed, a haematoma in the soft tissue was usually found.
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534
A. LINDSTRAND AND W. MORTENSSON
Fig. 4. Maximum displacement index for each ankle when examined (a) without and (b) with local anaesthesia, irrespective of whether additional provocation load was applied to the lower leg or not. Group 1: Normal anterior talofibular ligament. Group 2: Non-ruptured ligament, with macroscopically abnormal appearance. Group 3: Ruptured ligament. Reference group: The uninjured ankles of the patients in Groups 1 to 3.
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Group
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The material was classified into 3 groups according to the condition of the anterior talofibular ligament as observed at operation (Table 1). Results of radiography. The series was complete in 24 of the ankles in group 3 (ruptured anterior ligament) and in 24 of the uninjured ankles (reference group). When the examination was made without anaesthesia and without load provocation, the mean value for the displacement indices did not differ significantly in the various groups (Tables 2, 3). After a load had been applied to the lower leg, the displacement increased in cases with an abnormal anterior ligament (groups 2, 3). With increased provocation force in addition to local anaesthesia, the displacement further increased, particularly when the force was applied for two minutes. Increasing the provocation force caused a greater anterior displacement in the ankle joint than did local anaesthesia only (Table 3). The combination of both procedures increased the displacement. The mean maximum displacement index for all cases in group 3, when examined without anaesthesia, was 128 for isolated anterior talofibular ruptures and also for anterior talofibular combined with partial ca1caneofibular ruptures. The combined anterior talofibular and total ca1caneofibular ruptures had a mean value of 156. In local anaesthesia, these mean maximum displacement indices were 182 for isolated anterior ruptures, 140 for anterior and partial ca1caneofibular, and 225 for anterior and total ca1caneofibular ruptures. All 9 patients with an intact anterior ligament had a displacement index less than 90 when examined without local anaesthesia (Fig. 4 a). This value was therefore considered as the normal upper borderline. Based on this criterion, the sensitivity of the examination method was low in diagnosing acute rupture of the anterior ligament when the examination was made without local anaesthesia; only about two thirds of the cases with ruptured anterior ligament had displacement indices above 90
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
535
ANTERIOR INSTABILITY IN THE ANKLE JOINT
Table 3 Anterior displacement of the talus in 24 ankles with acute ankle sprain and rupture of the anterior talofibular ligament confirmed at operation (Group 3) and in 24 uninjured ankles (reference group). All were examined according to the complete examination schedule. The degree of anterior displacement was expressed in an index
Group 3
Reference Group Mean SD
n
Range
Mean SD
n
0-94 0-258 48-303
26 87 123
33 69 64
24 24 24
0-95 0-200 0-200
16 33 48
24 24 24
9-188 0-259 105-296
72 138 177
48 70 52
24 24 24
Range A. Without local anaesthia I. No additional provocation 2. Additional provocation 1/2 min 3. Additional provocation 2 min
25 55 60
B. With local anaesthesia
I. No additional provocation 2. Additional provocation 1/2 min 3. Additional provocation 2 min Significance levels of differences between mean values
AI v. A2p
ANTERIOR INSTABILITY IN THE ANKLE JOINT FOLLOWING ACUTE LATERAL SPRAIN A. LINDSTRAND and W. MORTENSSON
The lateral ligaments of the ankle are of the utmost importance for the stability of the joint. The anterior talofibular ligament (in the following called the anterior ligament) is often ruptured in ankle sprains (BROSTROM 1964, CEDELL 1967). Persistent discomfort after ankle sprain is often due to defective healing of the ligament (BROSTROM 1966). Opinions differ about the treatment of the acute rupture. This uncertainty, at least partly, reflects the lack of precise diagnostic criteria for this ligament lesion. When avulsion of the attachment of the ligament to the bone has occurred, the diagnosis is usually made directly by radiographic demonstration of the bone fragment. However, the rupture usually occurs solely in the ligament tissue itself (BROSTROM 1964). In that event, the diagnosis must be based on indirect evidence, either the demonstration of displacement of the talus or the leakage of contrast medium from the joint at arthrography. After division of the anterior ligament of corpses, the talus may be dislodged anteriorly (DEHNE 1933, ANDERSON et coli. 1952, CASTAING & DELPLACE 1972). Under clinical conditions, the displacement of the talus, in an acute rupture, is usually blocked by muscle defence evoked by pain but may be demonstrated by provocation. This fact has been used to diagnose the rupture at clinical examination (LINDSTRAND 1976) and at radiography (ANDERSON et coil. 1952, RUTH 1961, COUTTS & WOODWARD 1965, CASTAING & DELPLACE 1972, REICHEN & MARTI 1974), usually only Submitted for publication 10 March 1976. Acta Radiologica Diagnosis 18 (1977) Fasc. 5 September
34- 775845
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
529
530
A. LINDSTRAND AND W. MORTENSSON
Fig. 1. Equipment for examination of anterior stability of the ankle joint. The patient's leg is raised, supported at the heel, and rotated inwards about 30°. A sandbag hangs on the lower leg to provoke displacement. The projection is checked by fluoroscopy.
single cases are reported, and the diagnostic value of radiography has not been adequately established. The present report deals with the diagnosis of acute rupture of the anterior ligament based on provoked anterior displacement of the talus demonstrated by radiography. The purpose was to compare the degree of anterior displacement of the talus, as demonstrated by radiography with the actual condition of the ligament, as observed at operation, and to define a suitable procedure for the radiography. Preliminary results were reported previously (MORTENSSON & LINDSTRAND 1974). Material
The material consisted of 68 patients, 42 men and 26 women, aged 14 to 47, mean age 26 years, with an acute ankle sprain. All had a history of indirect violence, usually a supination trauma. Only those patients were included who were considered to have anterior ligament rupture at physical examination (for a detailed description, see LINDSTRAND 1976). No patients with fractures or signs of injured medial collateral ligaments were included. In all the 68 patients, the surgical exploration was performed because of signs of ligament lesions, irrespective of the results of radiography. Radiography
The examination was usually performed within 3 days after the injury. Attempts were made to displace the talus anteriorly with the patient supine, his leg raised,
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
ANTERIOR INSTABILITY IN THE ANKLE JOINT
a
b
c
d
531
Fig. 2. Joint surfaces of tibia and talus run parallel and describe parts of concentric circles (a, c). This symmetry disappears when the talus is displaced anteriorly (b, d). With the aid of the transparent graph (Fig. 3), a line is drawn through the middle of the lower tibia and the centre of the 'tibial circle' (c). Another line paralleling this is drawn through the centre of the 'talar circle' (d). The perpendicular distance between these two lines indicates the anterior displacement of the talus. The displacement index is obtained by dividing this distance by the sagittal length of the tibial joint surface (all measures in mm) and multiplying by 1 000. The displacement index is 275 in the case reproduced.
supported at the heel, and rotated inwards about 30°, and the ankle joint slightly plantar-flexed (Fig. I). The need for complete muscle relaxation was explained to the patient. After the position of the joint had been checked by fluoroscopy, lateral projections were obtained. The correct projection was defined as one in which the joint surface of the talar trochlea was projected tangentially (Fig. 2 a). Six exposures were made according to the following schedule. The weight of the leg was allowed to act on the joint for about one minute, and one exposure was made. An additional provocation effort was then made by application of a sandbag weighing 4 kg to the lower leg. The effect was registered by two exposures after half a minute and two minutes, respectively. The same procedure was repeated after the area round the ligament had been locally anaesthetized by 6 to 10 ml carbocain 1 % without vasoconstrictor agents. For comparison, the uninjured ankle was also examined at the same time, but without anaesthesia, except in the first patients of the series. All films not fulfilling the demands according to the definition of a true lateral projection were excluded. The patients with a complete examination schedule were used for the analysis of the influence of variations of the procedure on the results.
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
532
A. LINDSTRAND AND W. MORTENSSON
Fig. 3. Transparent graph used to measure talar displacement. The film is placed on the transparent graph so that the tibial joint surface covers the arc corresponding in size and so that the elongated radius passes through the middle of the lower tibia. This line is transferred to the film which is then placed so that the talar trochlea covers a corresponding arc and the elongated radius parallels the first line. This line is also drawn on the film and the distance between the two lines represents the anterior displacement of the talus (see also Fig. 2 b, d).
The total material was used to evaluate the sensitivity and specificity of the method and its diagnostic value. In addition, 11 patients were subjected to radiography in epidural anaesthesia in connection with the operation; in 8 of these the uninjured ankle was also examined at the same time. Displacement index: In lateral projection, the joint surfaces of the tibia and the talus may be considered to describe arcs of concentric circles (Fig. 2 a, c). This congruity disappears when the talus is displaced (Fig. 2 b, d). The distance between the centres of these two circles indicates the degree of anterior displacement of the talus (Fig. 2 d). A transparent graph was used for the calculation (Fig. 3). Correction for varying geometric enlargement was made by dividing the measured anterior displaceTable 1 The condition of the anterior talofibular ligament at operation for acute ankle sprain
Group 1 Group 2 Group 3
Normal No rupture but abnormal macroscopic appearance Acute total rupture
11 5 52*
* Tn 5 patients combined with a complete and in 5 with an incomplete acute rupture of the ca\caneofibular ligament.
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
533
ANTERIOR INSTABILITY IN THE ANKLE JOINT
Table 2 Anterior displacement of the talus in ankles without rupture of the anterior talofibular ligament. All had recently sustained ankle sprains and had clinically suggested ruptures. At operation the ligament was found to be normal in 11 (Group I) and to have abnormal appearance in five (Group 2). Not all the ankles were examined according to the complete examination schedule. The degree of anterior displacement was expressed in an index
Group 2
Group 1 Range
Mean SO n
Range
0--63 0-65 0-85
15 33 45
21 29 43
9 6 3
0-50 0--233 23-132
0-103 0-87 0-205
37 49 76
41 55 60
8 7 9
26-200 100--196 67-125
Mean SO
n
33 90 78
28 101 76
3 4 2
86 159 99
78 68 30
4 3 3
A. Without local anaesthesia I. No additional provocation 2. Additional provocation 1/2 min 3. Additional provocation 2 min B. With local anaesthesia I. No additional provocation 2. Additional provocation 1/2 min 3. Additional provocation 2 min Significance of the differences AI v. A3 not significant HI v. B3 not significant AI v. 82 not significant
A I v. A3 not significant HI v. 83 not significant AI v. HI not significant
ment by the sagittal length of the tibial joint surface, the quotient being multiplied by I 000. The result was referred to as the displacement index. No correction was made for the various sizes of the tibial joint surface. Only the anterior displacement was measured; the concomitant medial rotation and the distal displacement of the talus were not considered. Statistical methods In constructing Table 3, differences between displacement index within the groups were estimated by the t-test for paired observations. Otherwise, quantitative differences were estimated by conventional t-test for unpaired observations. Confidence intervals for differences were made in the way described in Geigy's Scientific Tables (1971). In the text a 95 per cent confidence interval is given within brackets following the percentage number.
Results
Clinical results. At exploration, an acute rupture of the anterior talofibular ligament was most frequent. An additional partial or total rupture of the calcaneofibular ligament was found in one fifth of these cases. Two had an isolated rupture of the anterior tibiofibular ligament. If no fresh ligament rupture existed, a haematoma in the soft tissue was usually found.
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
534
A. LINDSTRAND AND W. MORTENSSON
Fig. 4. Maximum displacement index for each ankle when examined (a) without and (b) with local anaesthesia, irrespective of whether additional provocation load was applied to the lower leg or not. Group 1: Normal anterior talofibular ligament. Group 2: Non-ruptured ligament, with macroscopically abnormal appearance. Group 3: Ruptured ligament. Reference group: The uninjured ankles of the patients in Groups 1 to 3.
c;
~
~
~ 0
350
)50
300
30U
250
250
200
:. .-., '. '.'' ..
150
100 50
.,
·
.... ., '"r' , .' '" ,".:: ...... ·
Group Group I 2
Group
J
·
'.' :-:
r
150
· .... .,... · '
i'
2UO
',. :........
Reference Group
a
100
50
:-:-a
·,. · .,
,.
Group Group I
2
Group 3
b
The material was classified into 3 groups according to the condition of the anterior talofibular ligament as observed at operation (Table 1). Results of radiography. The series was complete in 24 of the ankles in group 3 (ruptured anterior ligament) and in 24 of the uninjured ankles (reference group). When the examination was made without anaesthesia and without load provocation, the mean value for the displacement indices did not differ significantly in the various groups (Tables 2, 3). After a load had been applied to the lower leg, the displacement increased in cases with an abnormal anterior ligament (groups 2, 3). With increased provocation force in addition to local anaesthesia, the displacement further increased, particularly when the force was applied for two minutes. Increasing the provocation force caused a greater anterior displacement in the ankle joint than did local anaesthesia only (Table 3). The combination of both procedures increased the displacement. The mean maximum displacement index for all cases in group 3, when examined without anaesthesia, was 128 for isolated anterior talofibular ruptures and also for anterior talofibular combined with partial ca1caneofibular ruptures. The combined anterior talofibular and total ca1caneofibular ruptures had a mean value of 156. In local anaesthesia, these mean maximum displacement indices were 182 for isolated anterior ruptures, 140 for anterior and partial ca1caneofibular, and 225 for anterior and total ca1caneofibular ruptures. All 9 patients with an intact anterior ligament had a displacement index less than 90 when examined without local anaesthesia (Fig. 4 a). This value was therefore considered as the normal upper borderline. Based on this criterion, the sensitivity of the examination method was low in diagnosing acute rupture of the anterior ligament when the examination was made without local anaesthesia; only about two thirds of the cases with ruptured anterior ligament had displacement indices above 90
Downloaded from acr.sagepub.com at UNIV OF MICHIGAN on July 8, 2015
535
ANTERIOR INSTABILITY IN THE ANKLE JOINT
Table 3 Anterior displacement of the talus in 24 ankles with acute ankle sprain and rupture of the anterior talofibular ligament confirmed at operation (Group 3) and in 24 uninjured ankles (reference group). All were examined according to the complete examination schedule. The degree of anterior displacement was expressed in an index
Group 3
Reference Group Mean SD
n
Range
Mean SD
n
0-94 0-258 48-303
26 87 123
33 69 64
24 24 24
0-95 0-200 0-200
16 33 48
24 24 24
9-188 0-259 105-296
72 138 177
48 70 52
24 24 24
Range A. Without local anaesthia I. No additional provocation 2. Additional provocation 1/2 min 3. Additional provocation 2 min
25 55 60
B. With local anaesthesia
I. No additional provocation 2. Additional provocation 1/2 min 3. Additional provocation 2 min Significance levels of differences between mean values
AI v. A2p
