Arch Orthop Trauma Surg (1983) 101: 287-290

Archives of Orthopaedic and Traumatic Surgery © J F Bergmann Verlag 1983

Contribution to Stress X-ray Visualization of the Fibular Ligaments H H Kiister and H W Springorum Orthopedic Clinic and Outpatient Clinic of the University of Heidelberg (Director: Prof Dr H Cotta) Schlierbacher Landstra Be 200a, D-6900 Heidelberg 1, Federal Republic of Germany

Summary To determine the extension of a lesion of the fibular ligament with customary techniques is a highly subjective matter, since it underlies personal evaluation criteria These criteria determine the indication for surgery Socalled fixation devices are now made available, to avoid a wide margin of errors and to provide a means of attaining standardized and reproducable findings, which facilitate clinical diagnosis. We examined the Scheuba-fixation device in terms of its diagnostic value In routine application in the clinic the device has proven to be useful, helping to decide on the proper treatment, especially in borderline cases. Zusammenfassung Die Bestimmung des Ausma Bes einer fibularen Bandlision unterliegt mit herk 6 mmlichen Untersuchungstechniken immer subjektiven Beurteilungskriterien Operationsindikationen werden hiervon abhingig gemacht Zur Vermeidung einer gro Ben Fehlerbreite und in der Hoffnung auf standardisierte und reproduzierbare Befunde werden sogenannte Halteapparate fur die klinische Diagnosestellung angeboten Die diagnostische Aussagekraft des Halteapparates nach Scheuba wurde von uns iberprift Die routinemaiige Anwendung in der Klinik hat sich bewaihrt und erleichtert besonders in Grenzsituationen die Entscheidung fr das indikatorische Vorgehen.

A clear distinction cannot be made between the classical distorsion after Watson-Jones with concomitant lesion of the ligaments, while maintaining the joint stability, and the so-called "ligamentous ankle fracture" after Lauge-Hansen Using customary clinical parameters, it is often quite difficult to determine the exact extension of a lesion of the ligaments.

Because of diagnostic uncertainties, the unsupported diagnosis "distorsion of the anklejoint" is often made in case of the most frequent ligamentous injury, the lesion of the fibular ligaments of the ankle joint, thus avoiding to define the extension of the ligamentous damage exactly Objectified and standardized examination methods are necessary for the appropriate conservative or operative treatment of more severe ligamentous lesions; otherwise joint instabilities favouring arthrosis may occur. According to literature data, in about 80 per cent of all ruptures of the fibular ligaments the anterior ligament is affected In fact, in about two thirds of these cases, only the anterior ligament is ruptured The last third suffers from an additional lesion ofthe fibulocalcaneal ligament, sometimes even from a rupture of all three lateral ligaments Isolated lesions of the fibulocalcaneal or the posterior talofibular ligament hardly ever occur. Swellings, skin discolorations from hematomae, and pain caused by pressure and stretching in the course of the damaged ligaments are the symptoms which can lead to the tentaive diagnosis of an isolated or combined lesion of the ligaments Only with the examiner's manual skill and experience-esp after muscular tension arising from pain has been eliminated-it is possible to recognize clinically whether or not an instability is caused by rupture. But it is highly subjective to evaluate the extension of the lesion-upon which the indication for surgery is based-according to its clinical picture alone To avoid such subjective evaluation, as well as excluding bone trauma, we use X-ray visualization of the ankle joint, documenting ligamentous lesion with so-called "stress X-rays" Here, in the case of an existing ligamentous instability, evidence is given through the position of the talus in subluxation, with X-rays being taken sagittally and laterally.

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H H Kiister and H W Springorum: X-ray Visualization of the Fibular Ligaments

Fig 1 I anterior fibulotalar ligament 2 fibulocalcaneal ligament, 3 posterior fibulotalar ligament Fig 4 a Tibiolateral subluxation with stressed anterior drawer sign (20 kp)

Fig 2 Position of the ligaments (see Fig 1) in plantarflexion

Fig 4 b Anterior drawer sign; the direct distance (a) dorsal edge of the tibia-trochlea of the talus is measured

Fig 5 A Supination stress B Anterior drawer sign with intact ligaments (oB)

Fig 3 Supination-inversion visualization

stress (20 kp) in a p

X-ray

Before, the stress X-rays were normally taken with the examiner standing in the ray path In our opinion mechanical aids should be used in the future, in order to meet the regulations for radiological protection, to protect the examiner from an unnecessary exposure to radiation, and to ensure the most secure X-ray documentation of ligamentous damages, being possible If, on the basis of the clinical diagnosis, a lesion

H H Kiister and H W Springorum: X-ray Visualization of the Fibular Ligaments

Fig 6 Isolated division of the anterior ligament (A)

Fig 7 Division of the anterior (A) and the fibulocalcaneal ligament (C)

Fig 8 Division of all fibular ligaments (A-C-P)

of the fibular ligaments is suspected, we therefore use a so-called ,,Scheuba fixation device"; this device can be used to examine the stability of the ankle joint by means of X-rays taken laterally and sagittally Investigations about the diagnostic value have been made by us:

Normally, the talofibular ligament is in a relaxed and horizontal position (Fig 1) In plantar flexion with simultaneous supination of the metatersal and calcaneal part of the foot, the anterior ligament contracts and underlies most severe stress caused by traction, the fibulocalcaneal and the posterior talofibular ligament being relaxed to a large extent After dividing the anterior ligament in postmortem experiment, or after its rupture under supinationinversion stress (Fig 2), and when the ankle joint is opened and constant supination force applied, the fibulocalcaneal ligament is strained until it tears On sustained luxation stress from the upper trochlea of the talus, the posterior ligament may also tear.

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In our post-mortem experiments with the above mentioned fixation device, we took lateral and sagittal X-rays with a lateral and ventral maximum pressure of 20 kp for examination The foot was fixed in plantigrade inner rotation at an 200 angle (Fig 3 and 4). Naturally, by means of X-ray in lateral and sagittal standard view, proof cannot be made of an essential opening or anterior drawer sign in the case the undamaged lateral ligements On application of the same technique it normally is of the same quality on both sides Tilting the talus up to an angle of 50 and an anterior drawer sign 5 mm meet the standard (Fig 5). In the case of a so-called hypermobility or a chronic instability of the talocrural ligaments, the angles and the anterior displacement are beyond the just mentioned values and can be differentiated by comparing them with the contralateral side of fresh ligamentous lesions. After a complete, isolated division of the anterior ligament the tibiotalar angle opens more than 5 degrees Higher evidence is given, on the other hand, through lateral X-ray visualization of the anterior drawer sign of the talus, with a displacement acounting to more than 10 mm (Fig 6); because, due to anatomical facts, the fibulotalar ligament at a plantigrade position prevents the luxation of the talus in the sense of the drawer sign At an isolated rupture of the anterior ligament and intact ligaments of the inner malleolus, the talus, with its turning-point in the area of the inner malleolus, slides ventrally until the fibulocalcaneal ligament is strained Displacement exceeds the angle of the medial opening in a p X-ray visualization. With an additional division of the fibulocalcaneal ligament, the a p X-rays show a distinct opening of the tibiotalar joint angle which exceeds 150 and a ventral displacement of more than 15 mm, when the X-rays are taken laterally (Fig 7) After dividing the posterior ligament as well, only the tension from the peroneal tendon and the intact medial ligaments prevent a complete luxation of the talus Here, as expected, X-ray visualization shows a considerable opening (Fig 8) Clinical application, in this very case however, had made clear that the luxation of the talus can be visualized more distinctly by a p X-rays, because of the course of the peroneal tendon. Summarizing, the advantages of the fixation device are the following: the examiner is not exposed to radiation, under steadily and very slowly increasing pressure up to 20 kp normally local or neural anethesis is not necessary, and, at proper application of the device, the results are not dependent on the examiner's evaluation Repeatedly taken photographs are comparable when the same technique is applied

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H H Kiister and H W Springorum: X-ray Visualization of the Fibular Ligaments

and can be used for documenting the results after completed treatment of revealing remaining instabilities at an early stage. The isolated ligamentous rupture, occuring in two thirds of all ruptures of the fibular ligaments, can be shown most convincingly by lateral X-ray visualization in the fixation device Secure diagnosis of further combined ligamentous lesions is possible through X-rays taken laterally as well as sagittally Excluding a general ligamentous insufficiency in the sense of hypermobility or an old posttraumatic instability through comparison with the contralateral side, an anterior drawer sign of 5 to 10 mm stands for an isolated and more than 10 mm for a combined rupture of the anterior ligament The rarely occuring isolated rupture of the fibulocalcaneal ligament can only be visualized distinctly by means of a p X-ray photographs. In clinical application, which will be documented separatly, patients with strong muscles and defense reactions due to pain have shown-especially in the visualization of the anterior drawer sign-deviations from the values found by us Nevertheless, the routine

application of the fixation device in the case of a suspected lesion of the fibular ligament has been proved X-ray visualization is performed anteriorly and posteriorly, as well as, in the case of positive findings, on both sides Particularly in borderline cases and irrespective of the subjective clinical impression, decisions can thus be made easier on whether or not surgery is needed.

References Dannegger M (1979) Bandrupturen am oberen Sprunggelenk. Diagnose und Therapie Fortschr Med 97 :962 Dietschi C, Zollinger H (1973) Beitrag zur Diagnostik der lateralen Bandverletzungen des oberen Sprunggelenkes. Z Orthop 11: 724-731 Hufpauer W (1970) Beitrag zur Diagnostik der frischen fibularen Bandruptur Mschr Unfallheilk 73 :178 Jiger M, Wirth CJ (1978) Kapselbandlasionen Thieme, Stuttgart Lauge-Hansen N (1949) "Ligamentous" ankle fractures Diagnosis and treatment Acta Chir Scand 97: 544-549 Received March 5, 1983