A Randomized, Prospective Study of Operative and Non-Operative Treatment of Injuries of the Fibular Collateral Ligaments of the Ankle*

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1 Copyright 998 by The Journal of Bone and Joint Surgery, Incorporated A Randomized, Prospective Study of Operative and n-operative Treatment of Injuries of the Fibular Collateral Ligaments of the Ankle* BY P. POVACZ, M.D.f, SALZBURG, F. UNGER, M.D4, WELS, K. MILLER, M.D.t, R. TOCKNER, D.PHIL., AND H. RESCH, M.D.t, SALZBURG, AUSTRIA Investigation performed at General Hospital, Salzburg, and General Hospital, Wels ABSTRACT: One hundred and forty-six adults who had an isolated injury of the fibular collateral ligaments of the ankle were randomized to be managed operatively or non-operatively. Disruption of the ligaments was diagnosed by means of a physical examination and on the basis of stress radiographs of the ankle made with use of a specially designed device to hold the leg. Operative treatment, performed in seventy-three patients, consisted of suture repair of the disrupted ligaments within seventy-two hours after the injury, followed by immobilization of the ankle in a below-theknee plaster cast for six weeks. n-operative treatment, used for seventy-three patients, consisted of the use of an ankle orthosis for six weeks. After a minimum of two years of follow-up, we could detect no significant differences, with the numbers available, between the two groups with regard to the functional result or the degree of joint laxity that was evident on stress radiographs. The non-operative group lost a mean of.6 weeks from work, and the operative group lost a mean of 7. weeks. We concluded that non-operative treatment of an injury of the fibular collateral ligaments of the ankle yields results that are comparable with those of operative repair and is associated with a shorter period of recovery. Most orthopaedic surgeons prefer to treat injuries of the fibular collateral ligaments of the ankle nonoperatively. Some authors have advocated operative repair of severe injuries, especially in young athletes and physically active individuals - 4. The rationale for operative repair is that non-operative treatment is occasionally followed by chronic laxity of the ankle that compromises the patient's ability to return to normal athletic activities. To date, this issue has not been addressed by a prospective clinical study, to our knowledge. The purpose of the present study was to compare * benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. funds were received in support of this study. tgeneral Hospital, Mullner Hauptstrasse 48, A-5 Salzburg, Austria. address for Dr. Povacz: g.eigenherr@lkasbg.gv.at. ^General Hospital, Grieskirchnerstrasse 4, A-46, Wels, Austria. Technical University, Technikerstrasse 3, A-6, Innsbruck, Austria. the functional and radiographic results of operative and non-operative treatment of injuries of the fibular collateral ligaments of the ankle. Materials and Methods One hundred and sixty-seven patients who had an acute injury of the fibular collateral ligaments of the ankle and were seen at one of two trauma centers General Hospital, Salzburg, or General Hospital, Wels between January and August 99 were enrolled in the study. After giving informed consent, each patient was randomized into either the operative or the nonoperative group in a blinded manner with the use of computer-generated randomization cards. patient refused the treatment determined by the randomization process. Seventy-nine patients were randomized into the operative group and eighty-eight patients, into the nonoperative group. Twenty-one patients (six from the operative group and fifteen from the non-operative group) were lost to follow-up: eight patients had moved to an unknown address, and thirteen were satisfied with the result and were unwilling to be examined for the purpose of the study. ne of the thirteen patients had a subsequent operation. The remaining 46 patients (seventy-three in each group) were available for longterm follow-up evaluation. Patients were included in the study if they had closed epiphyseal growth plates, were less than forty years of age, and had sustained the injury within twentyfour hours before our initial evaluation. Patients were excluded if they had a history of an injury or instability of the ankle; if they had multiple injuries; or if the findings on stress radiographs did not meet the criteria for an acute rupture of the fibular collateral ligaments, as will be described. Disruption of the fibular collateral ligaments was diagnosed when there had been a supination injury and the physical findings included pain, tenderness, and swelling on palpation of the ligaments. Anterior drawer testing was performed on both the injured and the uninjured (contralateral) ankle. Standard anteroposterior and lateral radiographs were made to rule out any associated fractures. Stress radiographs were made for all patients with VOL. 8-A, NO. 3, MARCH

2 346 P. POVACZ, F. UNGER, K. MILLER, R. TOCKNER, AND H. RESCH use of a specially designed device to hold the leg. The leg was stabilized in a lateral position on a small bench, and a sling was placed on the forefoot with the fifth metatarsal used as a lever (Fig. ). A four-kilogram weight was applied continuously to the sling for five minutes to produce fatigue of the peroneal muscles 6. Anteroposterior radiographs of the ankle then were made with the leg in the holding device. An acute rupture of the ligament was diagnosed when the talar dome was tilted, in relation to the tibial plafond, by at least 5 degrees more than it was tilted on the contralateral side, which was evaluated with the same type of radiographic examination (Fig. ). There were ninety-four male patients and fifty-two female patients. The mean age was twenty-three years (range, sixteen to thirty-nine years). The right ankle was involved in eighty-one patients and the left ankle, in sixty-five. Most of the injuries had occurred during sports activities: thirty-four patients sustained the injury while playing soccer; twenty, while jogging; fifteen, while playing basketball; fifteen, while playing tennis; and thirteen, while playing volleyball. Forty-nine injuries had not occurred during sports activities. There were no significant demographic differences between the operative and non-operative groups. FIG. Photograph of the device that was used to hold the leg when stress radiographs of the ankle were made. A four-kilogram weight was continuously applied to the sling of the device for five minutes before the radiograph was made, with the leg still in the device. Similar stress radiographs of the contralateral, uninjured ankle were made for comparison. TABLE I TIBIOTALAR TILT ON STRESS RADIOGRAPHS MADE AT THE INITIAL EVALUATION Tibiotalar Tilt (Degrees) Mean Range P Value* Tibiotalar tilt <5 degrees Operative group (n = 3) 8-5 n-operative group (n = 8) -5 Tibiotalar tilt >5 degrees Operative group (n = 4) 6-36 Ofm n-operative group (n = 45) Neither comparison revealed a significant difference (p <.5). The mean tibiotalar tilt measured on the stress radiographs was 8 degrees (range, 8 to 36 degrees) for the operative group and 5 degrees (range, to 4 degrees) for the non-operative group. This difference was not significant (p =.3) (Table I). Treatment Groups All seventy-three patients in the operative group had the repair within seventy-two hours after the injury. A curvilinear incision was made anterior to the tip of the lateral malleolus, and the anterior talofibular and calcaneofibular ligaments were visualized. Care was taken to avoid injury to the branches of the superficial peroneal nerve. After removal of all hematoma, the dome of the talus was inspected for cartilaginous damage. When the ligament had ruptured through the mid-substance, the ends of the ligament were reapproximated with use of one or two thin absorbable sutures (Vicryl -; Ethicon, Somerville, New Jersey). Rigid fixation of the ligament was rarely feasible. When there was avulsion from the bone, the ligament was reapproximated with use of sutures that were passed through.-millimeter drill-holes in the bone. All sutures were tied while the foot was held in a slightly pronated position. After closure of the wound, the leg was placed in a split below-the-knee cast. The cast was changed to a below-the-knee weight-bearing cast at one week, and patients were encouraged to bear weight as tolerated. The cast was removed six weeks postoperatively, and the patient was given instructions for proprioceptive muscle training and isometric exercises for the peroneal muscles. Patients who were randomized to the non-operative group were managed with an elastic wrap with ice and with elevation of the foot for three to seven days (mean, five days). When the swelling had subsided, a commercially available ankle brace (Aircast, Summit, New Jersey) was fitted and the patient was told to wear the brace and bear weight as tolerated for six weeks. Range-ofmotion exercises of the ankle as well as proprioceptive and isometric exercises were performed to strengthen the peroneal muscles. The patients in both groups were encouraged to perform the prescribed exercises until the symptoms THE JOURNAL OF BONE AND JOINT SURGERY

3 OPERATIVE AND NON-OPERATIVE TREATMENT OF INJURIES OF THE FIBULAR COLLATERAL LIGAMENTS 347 FIG. Anteroposterior stress radiographs of a twenty-nine-year-old man who had a severe sprain of the right ankle. The tibiotalar tilt was 4 degrees on the side of the injury and degrees on the contralateral side. resolved. At the time of the latest follow-up, fifty-one (7 per cent) of the patients in each group indicated that they had complied with this recommendation. Patients were allowed to return to work as soon as they had a normal gait and were sufficiently pain-free to perform their normal work duties. Follow-up Evaluation At a mean of twenty-seven months (range, twentyfour to thirty-one months) after the completion of therapy, the patients were evaluated by examiners who had not been involved in their management. The range of motion of the ankle, anteroposterior stability, the maximum circumference of the calf, and tenderness of the ankle were assessed on physical examination. Stress radiographs of the injured and contralateral ankles were made with use of the same technique as before treatment. A joint was deemed to be stable when no instability was evident on clinical examination and the stress radiographs showed a less than 5-degree difference in the tibiotalar tilt between the injured and uninjured ankles. The subjective and objective results were evaluated with use of a 3-point scoring system (Table II): the result was poor when the score was less than points, good when it was to 4 points, and excellent when it was 5 to 3 points. In addition, the patient was asked to rate the outcome of treatment as excellent, good, fair, or poor. Statistical Methods All data were analyzed with an IBM 486 personal computer and software programs from IDV Experimental Planning and Data Analysis (Gauting, Munich, Germany). The median, standard deviation, standard error, range, upper and lower quartile, and total mean value were calculated for each group. Univariate analyses were performed with use of the Wilcoxon-Mann-Whitney U test for continuous variables and a chi-square test on a x table for binary variables (Fisher exact test). P values of less than.5 were considered significant. Results Operative Findings At the time of the operation, all seventy-three patients in the operative group were found to have a rupture of at least one component of the fibular collateral ligament complex. Twenty-nine patients (4 per cent) had an isolated rupture of the anterior talofibular ligament: twenty-seven of them had a rupture of the midsubstance, and two had an avulsion of the ligament from the bone. Forty-two patients (58 per cent) had ruptures of the talofibular and calcaneofibular ligaments: thirtyfour of them had tears through the mid-substance, and eight had avulsions from the bone. Only two patients (3 per cent) had a rupture of all three components of the fibular collateral ligament complex. Subjective Results At the most recent follow-up examination, two (3 per cent) of the seventy-three patients in the operative group had severe pain, twenty-one (9 per cent) had mild pain, and fifty (68 per cent) had no pain. In the non-operative group, two patients (3 per cent) had severe pain, fifteen ( per cent) had mild pain, and fiftysix (77 per cent) had no pain. Five patients (7 per cent) in the operative group reported swelling, and 68 (93 per cent) reported no incidents of swelling. In comparison, six patients (8 per cent) in the non-operative group VOL. 8-A, NO. 3, MARCH 998

4 348 P. POVACZ, F. UNGER, K. MILLER, R. TOCKNER, AND H. RESCH reported swelling and sixty-seven (9 per cent) reported no swelling. Sixty-nine patients (95 per cent) in the operative group and sixty-six patients (9 per cent) in the nonoperative group could walk on the lateral edge of the involved foot without difficulty. Overall, 43 (98 per cent) of the 46 patients had resumed sports activities after treatment. In the operative group, sixty-six patients (9 per cent) reported that they had returned to the same level of sports activity and seven ( per cent) reported that they participated at a lower level. In the non-operative group, sixty-three patients (86 per cent) reported that they had returned to the same level of activity and seven ( per cent) said that they participated at a lower level; three patients did not engage in any type of sports before or after the injury. Sixty-six patients (9 per cent) in the operative group and sixty-two (85 per cent) in the non-operative group thought that the ankle was stable. These subjective assessments of stability did not correspond directly to the objective measurements of instability. Only six of the sixteen patients who had radiographic evidence of instability reported that they had a sensation of instability during daily activities or sports. Twenty patients (7 per cent) in the operative group and eighteen (5 per cent) in the non-operative group reported recurrent sprains of the ankle during the period, of follow-up. A fear of sprains was reported by 3 patients (3 per cent) in the operative group and by eighteen (5 per cent) in the non-operative group. Of the seventy-two patients in the operative group who were willing to score the result, thirty-three (46 per cent) rated it as excellent; twenty-six (36 per cent), as good; twelve (7 per cent), as fair; and one ( per cent), as poor. Of the sixty-eight patients in the non-operative group who rated the result, thirty-four (5 per cent) considered it excellent; twenty-one (3 per cent), good; twelve (8 per cent), fair; and one ( per cent), poor. Therefore, in the entire series, the result was considered excellent or good by 4 (8 per cent) of the 4 patients who rated it. Sixty-three patients in the operative group and sixty-seven patients in the non-operative group said that they would have the same treatment again. Physical Findings Sixty-two (85 per cent) of the seventy-three patients in the operative group had no loss of active motion, and seven ( per cent) had a 5 to -degree loss of dorsiflexion and a 5 to -degree loss of plantar flexion compared with the contralateral, uninjured ankle. A loss of more than degrees was found in four patients (5 per cent): one had a 5-degree loss of dorsiflexion, and three had a -degree loss of plantar flexion. In the non-operative group, no loss of motion was noted in seventy patients (96 per cent), there was a -degree loss of dorsiflexion in two (3 per cent), and there was a -degree loss of plantar flexion in one ( per cent). TABLE II SCORING SYSTEM USED AT THE FOLLOW-UP EXAMINATION* Stability (objective) Stable Unstable Stability (subjective) Stable, no difference from the uninjured side Occasional feeling of instability when walking, no giving-way Mild feeling of instability and slight, spontaneous giving-way Occasional sprains with pain and swelling Frequent sprains, even in the presence of mild pressure Constant giving-way, even in the presence of mild pressure Fear of sprain Frequency of sprains Never Once a month, week, or day Pain ne Mild, rare episodes Severe, frequent episodes Swelling Ability to walk on the lateral edge of the foot difficulty Poor ability Unable Extent of movement (compared with contralateral side) Same Loss < degrees Loss > degrees Sensitivity rmal Reduced Capacity for sports / am now as proficient in sports as I was before the injury. True Undecided t true My foot is no problem in sports. True Undecided t true Subsequent treatment Would you be willing to have the same treatment again? Points *A score of 5 to 3 points was considered an excellent result; to 4 points, a good result; and less than points, a poor result. The maximum circumference of the calf of the involved limb was one to two centimeters greater than that of the contralateral limb in four patients in the THE JOURNAL OF BONE AND JOINT SURGERY

5 OPERATIVE AND NON-OPERATIVE TREATMENT OF INJURIES OF THE FIBULAR COLLATERAL LIGAMENTS 349 TABLE SCORE AT THE FOLLOW-UP EXAMINATION Result* Excellent Good Poor PValuet Tibiotalar tilt <5 degrees Operative group (n = 3) n-operative group (n = 8) Tibiotalar tilt >5 degrees Operative group (n = 4) n-operative group (n = 45) (65) (75) 9 (69) 4 (53) (3) (8) 5() (4) 4(3) (7) 8 (9) () *The values are given as the number of patients, with the percentage in parentheses. tneither comparison revealed a significant difference (p <.5), with the numbers available. operative group; the other sixty-nine patients had no difference between the circumferences of the two calves. patient in the non-operative group had atrophy of the muscles of the calf. The anterior drawer test was positive (indicating an unstable ankle) for seven patients ( per cent) in the operative group compared with sixteen patients ( per cent) in the non-operative group. With the numbers available, we could detect no significant difference in the physical findings between the operative and non-operative groups at the time of the latest follow-up (p =.675). Radiographic Results The mean tibiotalar tilt, which had been 8 degrees (range, 8 to 36 degrees) in the operative group and 5 degrees (range, to 4 degrees) in the non-operative group at the time of the injury, improved to 6 degrees (range, to 7 degrees) in the operative group and to 6 degrees (range, to 6 degrees) in the non-operative group at the latest follow-up examination (Figs. 3-A and 3-B). With the numbers available, we could detect no significant difference between the groups with regard to the tibiotalar tilt (p =.4), irrespective of the degree of instability at the time of the injury. Complications Associated with Treatment In the operative group, two patients had necrosis of the skin along the margin of the wound, which healed without additional operative intervention. infections developed, but eight patients had paresthesias in the region of the operative scar at the time of follow-up. treatment-related complications occurred in the nonoperative group. Overall Results The overall result was excellent (mean score, 9 points) for forty-nine patients in the operative group, good (mean score, points) for twelve, and poor (mean score, 5 points) for twelve. In the non-operative group, FIG. 3-A FIG. 3-B Anteroposterior stress radiographs of the left ankle of a twenty-seven-year-old man, made before non-operative treatment (Fig. 3-A) and at the two-year follow-up examination (Fig. 3-B). VOL. 8-A, NO. 3, MARCH 998

6 35 P. POVACZ, F UNGER, K. MILLER, R. TOCKNER, AND H. RESCH the overall result was excellent (mean score, 9 points) for forty-five patients, good (mean score, 3 points) for sixteen, and poor (mean score, 3 points) for twelve. With the numbers available, we could detect no significant difference between the two groups with regard to the overall result (Table III). The patients in the nonoperative group resumed their normal work activities at a mean of.6 weeks (range, to eight weeks) after the injury, whereas those in the operative group returned to normal work activities at a mean of 7. weeks (range, two to twelve weeks). This difference was found to be significant (p <.). Discussion The treatment of an acute rupture of the fibular collateral ligaments of the ankle has generated much controversy in the literature because the long-term prdgnosis has been favorable for most patients, independent of the method of treatment. Kannus and Renstrom compared the results after operative and non-operative treatment in seven studies in the literature and concluded that non-operative treatment was superior. However, this finding should be evaluated with caution, as the results of operative and non-operative methods Were directly compared in only one of the studies 8, a previous injury of the ankle was a criterion for exclusion in only four of the studies 58 ', and there were relatively small populations and short durations of follow-up in all of the studies. A frequently cited study by Freeman consists of a comparison between only eighteen patients who were managed operatively and twelve patients who were managed noh-operatively. Kaikkonen et al. concluded that non-operative treatment with early mobilization of the ankle yielded better results than operative repair with early mobilization. Brostrom, Gronmark et al., and Korkala et al. all recommended operative repair for the treatment of young athletes, and proponents of operative treatment have consistently pointed out the necessity of an operation for athletes 4 ' 735. Operative treatment has been recommended for athletes in recent textbooks as well - 3. However, this opinion has been countered by authors of comparative studies 9-4 who have recommended early non-operative treatment even for athletes. The present study was designed to assess the value of operative treatment of severe sprains of the ankle in young adults, most of whom were athletes. A major limitation of the present study was the relatively small subgroup of patients (nineteen in the operative group and seventeen in the non-operative group) who had complete instability of the ankle (a tibiotalar tilt of more than degrees) that is, the group that is most often considered for operative treatment. Despite this limitation, our study demonstrated no advantage of operative treatment compared with nonoperative treatment alone, irrespective of the degree of post-traumatic instability. With the numbers available, no significant difference was found between the two groups with regard to objective or subjective stability, the functional scores, or the overall result. Our data suggest that there is a discrepancy between the patient's sensation of instability and the findings on physical examination and on stress radiographs. Of the 3 patients who had objective stability of the joint at the follow-up examination, only 4 subjectively rated the joint as being stable. The remaining nine patients reported symptoms of chronic laxity and giving-way of the joint. Conversely, only nine of the twenty-three patients who had objective instability of the joint considered the joint to be unstable. The remaining fourteen patients reported no symptoms of instability. This discrepancy is probably a result of the limitation of physical and radiographic examination with regard to the detection of chronic instability of the ankle. The mean interval between the injury and the return to normal work activities was.6 weeks for the patients in the non-operative group and 7. weeks for the patients in the operative group. This difference was found to be significant (p <.) and was attributable to the use of a cast postoperatively. We no longer consider such immobilization to be necessary, as we believe that equivalent results can be achieved by placing the ankle in a splint once the operative wound has healed. On the basis of the results of the present randomized, prospective study, we recommend non-operative treatment of a sprain of the ankle in young adults, including those who are involved in athletic activities. A study of a larger series of patients who have a severe sprain that involves all components of the fibular collateral ligament complex is necessary to determine the role, if any, of operative intervention in this subgroup of patients. References. Bernett, P., and Schirmann, A.: Akute Sportverletzungen des Sprunggelenkes. Unfallheilkunde, 8:55-6,979.. Brand, R. L.; Collins, M. D.; and Templeton, T.: Surgical repair of ruptured lateral ankle ligaments. Am. J. Sports Med., 9:4-44, Brostrom, L.: Sprained ankles. V. Treatment and prognosis in recent ligament ruptures. Acta Chir. Scandinavica, 3: , Eggert, A.; Griiber, J.; and Darda, L.: Zur Therapie von Aupenknocheldbandverletzungen. Randomstudie zur postoperativen Therapie und fruhfunktionellen Behandlungstaktik. Unfallchirurg, 89:36-3, Freeman, M. A. R.: Treatment of ruptures of the lateral ligament of the ankle. J. Bone and Joint Surg., 47-B(4): , Gronmark, T.; Johnson, O.; and Kogstad, O.: Rupture of the lateral ligaments of the ankle: a controlled clinical trial. Injury, : 5-8, Jaskulka, R.; Fischer, G.; and Schedl, R.: Injuries of the lateral ligaments of the ankle joint. Operative treatment and long-term results. Arch. Orthop. and Traumatic Surg., 7: 7-,988. THE JOURNAL OF BONE AND JOINT SURGERY

7 OPERATIVE AND NON-OPERATIVE TREATMENT OF INJURIES OF THE FIBULAR COLLATERAL LIGAMENTS Kaikkonen, A.; Kannus, P.; and Jarvinen, M.: Surgery versus functional treatment in ankle ligament tears. A prospective study. Clin. Orthop., 36:94-, Kannus, P., and Renstrom, P.: Current concepts review. Treatment of acute tears of the lateral ligaments of the ankle. Operation, cast, or early controlled mobilization. J. Bone and Joint Surg., 73-A: 35-33, Feb Katcherian, D.: Soft tissue injuries of the ankle. In Orthopaedic Update Knowledge, 994. Foot and Ankle, pp Edited by L. D. Lutter, M. S. Mizel, and G. B. Pfeffer. Rosemont, Illinois, The American Academy of Orthopaedic Surgeons, Korkala, O.; Lauttamus, L.; and Tanskanen, P.: Lateral ligament injuries of the ankle. Results of primary surgical treatment. Ann. Chir. Cynaec, 7:6-63,98.. Korkala, O.; Rusanen, M.; Jokipii, P.; Kytomaa, J.; and Avikainen, V.: A prospective study of the treatment of severe tears of the lateral ligament of the ankle. Internat. Orthop., :3-7, Krahl, H.: Kommentar zum Thema operative vs konservative Therapie der fibularen Bandruptur. Orthopdde, 8:34-344, Moller-Larsen, F.; Wethelund, J. O.; Jurik, A. G.; de Carvalho, A,; and Lucht, U.: Comparison of three different treatments for ruptured lateral ankle ligaments. Acta Orthop. Scandinavica, 59: , Neumann, K.: st die konservativ funktionelle Behandlung frischer Aupenbandruptur am OSG gerechtfertigt? Teil. Hefte Unfallheilkunde, 89:8-9,987. ' ' ' 6. Rockenstein, R.: Die frischen lateralen Bandverletzungen im oberen Sprunggelenk. Hefte Unfallheilkunde, 3:5-5, Riiter, A., and Burri, C: Verletzungen des oberen Sprunggelenkes. Hefte Unfallheilkunde, 3:39-4, Sommer, H. M., and Arza, D.: Die konservative funktionelle Behandlung der fibularen Kapselbandruptur auch beim Leistungssportler? Sportverletzung-Sportschaden, : 5-8, Sommer, H. M., and Arza, D.: Functional treatment of recent ruptures of the fibular ligament of the ankle. Internat. Orthop., 3: 57-6,989.. Spring, R., and Hardegger, E: Die frische Ruptur der fibulotalaren Bander operative Therapie und gipsfreie Nachbehandlung mit Spezialschuh. Helvetica Chir. Acta, 48:7-76,98.. van Moppens, E I., and van den Hoogenband, C. R.: Diagnostic and therapeutic aspects of inversion trauma of the ankle joint. Thesis, University of Maastricht, Maastricht, The Netherlands, 98. Utrecht/Antwerpen, Bohn, Scheltema and Holkema, 98.. Weise, K.; Rupf, G.; and Weinelt, J.: Die laterale Bandverletzung des OSG beim Sport. Aktuel Traumat., 8 (Supplement): 54-66, Zwipp, H.: Akute Bandlasionen. In Chirurgie des Fufles, pp Berlin, Springer, Zwipp, H.; Hoffmann, R.; Wippermann, B.; Thermsinn, H.; and Gottschalk, E: Fibulare Bandruptur am oberen Sprunggelenk. Orthopdde, 8:336-34,989. VOL. 8-A, NO. 3, MARCH 998