Osteochondritis dissecans tali: Diagnosis and therapy

Foot and Ankle Surgery 1996

2:229-238

Osteochondritis dissecans tali: diagnosis and therapy B. T H O M A N N , R. HESS A N D K. KLAUE Department of Orthopaedic Surgery, University of Bern, Bern, Switzerland

Summary Osteochondritis dissecans tali (ODT) is still considered a joint disease and is therefore treated primarily as a problem of the joint. It has been suggested that it should be considered as a separate disease resulting from an intra-osseous ganglion. ODT must be distinguished from traumatic flake fractures. By treating ODT as a bone problem and carrying out extra-articular debridement of the ganglion and a cancellous bone graft we achieved out of eight cases, four excellent, three good and one poor result. In all cases the cancellous bone graft was consolidated and the joints were congruent and non-arthritic. The diagnostic technique is also discussed herein: the most useful method is conventional radiography. If additional information is needed about size and location of the lesion, a computed tomography (CT) scan should be used.

Keywords" osteochondritis dissecans; ankle;

Introduction The pathogenesis of osteochondritis dissecans of the talus (ODT) is still unknown. A mechanical aetiology has been suggested [1, 2]. There may, however, be other mechanisms: mechanical microtrauma may cause small lesions in the joint cartilage which allow synovial fluid to penetrate the bone. Fluid then collects in the sub-chondral bone forming a cyst which presents as an intra-osseous ganglion while the joint cartilage remains in continuity or detaches as a chondral flake [3-5]. Bauer et al. [6] distinguished these lesions from the traumatic flake fractures, as described by Pettine et al. [7], and considered the first to be a true ODT. It is the purpose of this study to discuss the pathogenesis of and the diagnostic

Correspondence: Dr Kaj Klaue MD, Department of Orthopaedic Surgery, Inselspital,CH-3010Bern, Switzerland.

© 1996 Arnette BlackwellSA

ganglion

techniques for ODT, and to propose an operative technique for its treatment.

Materials and methods Seven patients, four men and three women (mean age 28 years), presenting with eight ankles have been treated in our department with a clinical and radiological diagnosis of ODT. One l~atient reported a history of trauma (malleolar fracture) and two had suffered repeated supination trauma. Two patients had previously been operated upon, on the same ankle and for the same diagnosis; another suffered from ligamentous laxity. In one case the diagnosis of ODT was made in the emergency department: a radiography after a malleolar fracture showed a preexisting sub-chondral cyst in the talus. The patient had also complained of typical symptoms for several months before the actual trauma. 229

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Figure 1

a, Case 6: CT-scan of the left ankle join{ in the coronal and horizontal views showing the posteromedial ODT; b, twodimensional reconstruction of the same joint.

In all cases the symptoms were similar. Most patients suffered from a burning or piercing pain w h e n bearing weight, but only had occasional rest pain. All complained of morning pain, localized directly over the anterior aspect of the ankle joint. None reported catching or locking. The mean time between the first symptoms and surgery was seven years. Various diagnostic techniques were used. All patients had conventional radiographs of the ankle. In addition, three patients had a CT-scan (Figure la, b), three had magnetic resonance imaging (MRI) (Figure 2), two had scintigraphy (Figure 3), and in one case conventional coronal tomography of the talus (Figure 4). The ankle score of Kitaoka [8] was used for clinical evaluation. This gives a m a x i m u m score of 100 points where various clinical factors are assessed, e.g. level of pain (45 points), activity level (10), walking

distance (10), limp (10), restriction of motion of hindfoot (10), and alignment (15). A result between 90 and 100 points was considered as excellent, 75 and 89 as good, 60 and 74 as fair, and "below 60 as poor.

Operative technique All operations were performed between February 1992 and July 1995 by the same surgeon (K. Klaue). A skin incision parallel and medial to the tendon of the tibialis anterior was chosen (Figure 5) and an antero-medial arthrotomy of the ankle joint was performed. The greater saphenous vein was preserved. Exploration of the joint can be carried out in m a x i m u m plantar flexion or, if necessary, with a femoral distractor placed between the tibia and the talus. Palpation of the cartilage is m a d e using a dissector. After localizing the lesion, the neck of the © 1996 Arnette BlackwellSA, Footand Ankle Surgery,2, 229-238

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Figure 2

Case 7: MRI of the left ankle joint in the coronal (a) and lateral (b) view, showing a centromedial ODT.

talus is exposed antero-rnediatly (Figure 6 and Figure 7a, b). A K-wire is drilled into the lesion under radiological control using an image intensifier (Figure 8a, b). A danger of penetration of the articular cartilage exists. A 4.5 m m hole is drilled on over the K-wire using the canulated drill system (Figure 8c). The cyst can then be debrided with a curette through the drill hole (Figure 8d). Special attention was paid to removal of the sclerotic bone which surrounds the ganglion, and cancellous bone is then taken from the medial malleolus using the same approach (about 2 c m 3 is sufficient). The cancellous bone is cut into small pieces with strong scissors and is packed without impaction into the enlarged bony hole. The arthrotomy allows for simultaneous intra-articular control of the integrity of the cartilaginous layer. After surgery the ankle is immobilized for 2 weeks in a below-knee plaster of Paris cast. The foot is then placed into a Walker for a further 6 weeks. During © 1996 Arnette BlackwellSA, Foot and Ankle Surgery, 2, 229-238

that time the hind foot will be fully actively mobilized without weight bearing. Low dose heparin (Fraxiparine) is given prophylactically for up to 10 weeks. Weight bearing is commenced after 8 weeks and radiographs are taken at 6, 12 and 52 weeks.

Results

All patients were reviewed at a m e a n follow-up time of 2.5 years (Table 1). Clinical results were considered excellent in four, good in one, fair in two and poor in one based on the Kitaoka score [8]. The poor result was observed in a patient w h o had been treated previously with the surgical release of a tarsal tunnel. Objectively he h a d a full range of movement of the ankle joint, normal alignment of the foot and radiologically the bone graft was integrated within a congruent joint.

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Figure 3

Case 8: scintigram showing a concentration of the radionucleoid within the right talus. The concentration within the left foot is due to an early paratendineous ganglion.

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The other six patients (with seven ankle joints) h a d m o d e r a t e p a i n daily; five w e r e limited in recreational activities and t w o w e r e limited in daily life. At followu p four w e r e pain-free a n d in three m o d e r a t e or occasional p a i n persisted daily. Three patients r e p o r t e d no restriction in their daily activity, in two

a limitation in recreational activities persisted and in one no change in the severe p r e - o p e r a t i v e s y m p t o m s w a s achieved. In this case a c y s t recurred after the operation, w h e r e the sclerotic wall of the cyst has b e e n insufficiently removed. N o i m p r o v e m e n t occurred after a revision operation. The r a d i o g r a p h s © 1996 Arnette Blackwell SA, Foot and Ankle Surgery, 2, 229-238

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Figure 5 Skin incision parallel to the tendon of the tibialis anterior muscle from the distal part of the tibia to the base of Os cuneiforme I. a: Tendon of tibialis anterior muscle; b: skin incision; c: saphenous vein; d: saphenous nerve.

Figure 4 Case 5: Conventional tomography in coronal view, with a medial ODT.

at follow-up showed that the bone graft had incorporated and the joint was congruent (Figure 9).

Discussion Soon after the first description of ODI by KOnig [19] the aetiology of the disease was discussed. Mechanical reasons were considered to be predominant and were supported by experiments [1, 2, 7, 9-11] in cadavers. Other reasons were also taken into consideration, e.g. familial pre-disposition [12] and disturbance of the fatty acid metabolism [13]. The consideration of pre-existing intra-osseous cysts has become more popular within the last two decades. Gschwend [15] observed intact joint cartilage intra-operatively, nevertheless the © 1996 Arnette Blackwell SA, Foot and Ankle Surgery, 2, 229-238

radiographs showed a clear osteocartilagineous separation. He called these lesions 'pseudo-ODT' and suggests different treatment by fixing them extraarticularly. Other authors recognised atypical ODT [3, 9, 11, 14]. However, in 1946 Freund [20] and in 1970 Jayson [16] presented a valvular mechanism which might be responsible for the development of juxta-articular cysts. Barth [3] and Cserati [4] also described intra-osseous lesions which develop by pumping synovial fluid into the bone underlying the osteocartilaginous layer. It became increasingly obvious that two different pathways to ODT are possible. Pettine [7] first suggested a classification of flake fractures without including the non-traumatic cases. Berruex [17] compared two groups' talar cysts and traumatic ODT. Finally Bauer [6] distinguished the aetiology of traumatic flake fractures and the 'real' ODT. We have included only cases with pre-existing sub-chondral cysts. All presented the typical viscous, gelatinous 'apple jelly' of bony ganglions with a membrane and

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Figure 6 Intra-operative view showing the neck of tile talus, the talonavicular joint and the long saphenous vein. The ring marks the correct entrance for the Kwire.

a sclerotic b o n y wall and all except one s h o w e d intact joint cartilage. These findings support the thesis subchondral ganglia are a separate disease. Nevertheless it needs some trauma or at least microtrauma of the cartilage at the onset of s y m p t o m s to bring about ODT. Joints with instability or a pathological laxity,

i.e. w h e r e shear forces occur, readily undergo microtrauma of the cartilage [18]. In this context it is interesting that two cases were observed that had to be revised for a tibialis posterior t e n d o n insufficiency. Thereafter, one case became pain-free, and the second h a d ' a fair result. © 1996 Arnette Blackwell SA, Foot and Ankle Surgery, 2, 229-238

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Distinguishing the flake fractures from the ganglions has consequences on the treatment. The latter can be treated by opening the ganglion and drilling the sclerotic bone walls. Drilling is performed extra-articularly and the cavity is packed with cancellous bone graft. The joint cartilage must not be touched and no fragment needs to be removed. Berruex [17] proposed an osteotomy of the medial malleolus for a better view of the joint. We do not use this approach as in our experience, the exposure is sufficient with maximal plantar flexion. Alternatively a femoral distractor can be used.

Diagnostic technique The most important diagnostic method is still the conventional radiography of the ankle joint, especially the antero-posterior view. Views at different degrees of flexion may be useful, although the lateral view is of minor importance and the lesion is hardly ever seen. The lesion can be located using conventional coronal tomography. This technique has now been replaced by CT. In one case, in which the diagnosis was missed for a long time, a scintigram did not demonstrate the diagnosis, although a slight local concentration of radionucleoid was seen within the talus. ODT can easily be located by coronal a n d / o r saggital cuts using MRI, and it may also give information about the content of the cyst. If there are suggestions of additional soft tissue problems, as in two cases of the tibialis posterior tendon dysfunction, we prefer this examination. In our experience the correlation of MRI to intra-operative assessment of the lesion was not always identical. CT scanning is the best form of imaging. The bony structures and the size of the lesion are reproduced correctly, the demarcation is sharp and the position of lesion can be precisely identified. If a patient reports pain in the ankle joint when bearing weight and at rest, with or without trauma, the orthopaedic surgeon should suspect ODT.

Figure 7

Correct placementof the drill with an extra-articularportal. © 1996 Arnette BlackwellSA, Footand Ankle Surgery,2, 229-238

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Figure 8 a, b, Placement of the K-wire intra-operatively with the image amplifier; c, drillhole with a canulated drill over the K-wire as shown in a; d, debridement of the cyst through the drillhole.

© 1996 Arnette Blackwell SA, Foot and Ankle Surgery, 2, 229-238

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Figure 9 Case 7: a, ODT pre-operatively centromedial (see also Figure 2); b, post-operatively, the cyst is filled and packed with cancellous bone which had been taken from the distal part of the tibia; c, 2 months after operation; d, 4.5 years after operation.

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Table 1

Patients and clinical data

Case

1. 2. 3. 4. 5. 6. 7. 8.

male, 55 years male, 28 years female, 28 years male, 30 years female, 28 years female, 30 years female, 22 years male, 43 years

History

Ankle pain Malleolar fracture Hyperlaxity ODT 10 years ago Ankle pain ODT 2 years ago Malleolar fracture Tarsal tunnel release

Kitaoka score Pre-op.

Follow-up

87 87 87 77 77 74 84 41

100 100 97 77 74 74 100 36

References 1 Berndt AL, Harty M. Transchondral fractures (osteochondritis dissecans) of the talus. J Bone Joint Surg 1951; 41A: 988-1020. 2 Zollinger H, Dexel M. Zur Aetiologie der Osteochondritis dissecans des Talus. Orthop4de 1981; 10: 92-94. 3 Barth E, Hagen R. Juxta-arficular bone cyste. Acta Orthop Scan 1982; 53: 215-217. 4 Cserati M. Question of post-traumatic formation of paraarticular bone cysts. Z Unfallmed Berufschr 1975; 68: 95-103. 5 Landell JW. The bone cysts of osteoarthritis. ] Bone Joint Surg 1953; 35B: 643-649. 6 Bauer RS, Ochsner PE. Zur Nosologie der Osteochondritis dissecans der Talusrolle. Z Orthop 1987; 125: 194-200. 7 Pettine K, Morrey B. Osteonchondral fractures of the talus. J Bone Joint Surg 1987; 69B: 89-92. 8 Kitaoka HB. Salvage of nonunion following ankle arthrodesis for failed total ankle arthroplasty. Clin Orthop 1991; 26B: 37-43. 9 Canale T, Belding RH. Osteochondral lesions of the talus. J Bone Joint Surg 1980; 62A: 97-102. 10 ROden S, Tilleg~rd P, Unander-Scharin L. Osteochondritis dissecans and similar lesions of the talus. Acta Orthop Scand 1953; 23: 51-66.

Follow-up

Subjectiveresults

Re-operation

4.5 years 8 months 4 months 5 months 2.5 years 1.5 years 4.5 years 2 years

excellent good good fair fair fair excellent poor

Augment. rib. post. none none none after 2 years none none Augment. tib. post.

11 Scharling M. Osteochondritis dissecans of the talus. Acta Orthop Scand 1978; 49: 89-94. 12 Stougard J. Familial occurrence of osteochondrifis dissecans. J Bone Joint Surg 1964; 4611: 542-543. 13 Zsemaviczky J. Hyperlipoprotein~imie als mOgliche Ursache der Osteochondritis dissecans. Z Orthop 1977; 115: 35-39. 14 Patterson RH, Jones M, Tuten R. Intraosseous ganglion cyst of the talus: Case report. Foot Ankle 1993; 14: 538-539. 15 Gschwend N, Munzinger U. Unsere Technik der extraartikul~ren Schraubenfixation der osteochondritis dissecans tali medialis. Orthop4de 1981; 10: 99-101. 16 Jayson MIV, Dixon J. Valvular mechanisms in juxta-articular cysts. Ann Rheum Dis 1970; 29: 415-420. 17 Berruex P, Pelet D. Dissectate an der Talusrolle. Orthopiide 1981; 10: 95-98. 18 Klaue K, Durnin CW, Ganz R. The acetabular rim syndrome. J Joint Bone Surg 1991; 73B: 423-429. 19 K6nig G. Ueber freier KOrper in den Gelenken. Deutsche Zeitschr Chr 1888; 27: 90-92. 20 Freund E. Pathological significance of intra-articular pressure. Edinburgh M J 1946; 47: 192-203.

© 1996 Arnette Blackwell SA, Foot and Ankle Surgery, 2, 229-238