Arch Orthop Trauma Surg (1991) 110 : 142-145

Achw°fOrt paedic

ndTrauma urgery © Springer-Verlag1991

Post-traumatic radioulnar synostosis after forearm fracture osteosynthesis G. Bauer, M. Arand, and W. Mutschler Abteilung fiir Unfall-, Hand-, Plastische- und Wiederherstellungschirurgie der Universit~it Ulm, W-7900 Ulm, Federal Republic of Germany

Summary. One hundred sixty-seven forearm fractures treated with plate osteosynthesis were analyzed for synostosis occurring between the radius and the ulna. Eleven cases (6.6%) were found, in 7 of which both bones of the forearm had been fractured, while the other 4 were cases of isolated radial or ulnar fracture. Overall there were 89 cases of fracture of both bones; of the 65 cases treated utilizing the two-incision approach, crossunion was seen in only 1, while in a comparable group (12 cases) in which the fractures were stabilized using the Boyd approach, there were 5 synostoses. In 38 cases of isolated ulna fracture, only 2 synostoses were seen one associated with severe soft-tissue trauma and the other airising after treatment with a modified Boyd approach. A m o n g 40 isolated radial fractures, 2 radioulnar synostoses occurred, one in an open fracture and the other after fixation via the Boyd approach. These results emphasize the importance of using two approaches for fractures of both forearm bones. The highest risk of postosteosynthetic synostosis appears to be in fractures of the proximal third of both radius and ulna.

Zusammenfassung. 167 mit Plattenosteosynthese versorgte Unterarmschaftfrakturen wurden hinsichtlich einer Brfickenkallusbildung analysiert. In 11 F~llen (6,6%) kam es zur radio-ulnaren Synostose, 7mal nach kompletter und 4real nach isolierter Fraktur. Bei den 89 kompletten Unterarmschaftbrfichen wurden nach operativer Versorgung fiber zwei Zuggnge (n = 65) nur in einem Fall mit Weichteilschaden ein Brfickenkallus beobachtet. Bei einem vergleichbaren Krankengut mit Stabilisierung fiber den Boyd'schen Zugang trat nach radialer und ulnarer Plattenosteosynthese ein Brfickenkallus in 5 von 12 F~illen auf. Isolierte Ulnafrakturen (n = 38) fiihrten 2mal zu einer Brfickenkallusbildung - einmal bei einem schweren Weichteiltrauma, im a'nderen Fall nach Versorgung fiber einen modifizierten Boyd'schen Zugang. Ebenfalls zweimal kam es bei einer isolierten Radiusfraktur (n : 40) zu einer radio-ulnaren VerbinOffprint requests to: Dr. G. Bauer, Chirurgische Universit~itsklinik, SteinhOvelstr. 9, W-7900 Ulm, Federal Republic of Germany

dung. In einem Fall handelte es sich um eine offene Fraktur, im anderen Fall um eine Fraktur, die fiber einen Boyd'schen Zugang versorgt wurde. Daher sollte zur Versorgung kompletter Unterarmschaftfrakturen wenn immer m6glich - zwei Zug~nge zu Radius und Ulna gew~ihlt werden. Besonders geffihrdet hinsichtlich der Entstehung der radio-ulnaren Synostose ist das proximale Schaftdrittel.

A synostosis between the radius and the ulna after conservative or surgical treatment of forearm fractures is rare and associated with significant functional impairment. In the literature, the incidence of radioulnar synostosis is reported as occurring in up to 5.5% of conservatively treated cases, but in up to 9.5% of operated cases [1, 7, 13-15, 18, 21]. A number of factors may predispose to synostosis: fracture of the radius and ulna at the same level, severe local trauma, interosseous membrane injury, fracture hematoma between radius and ulna, technical difficulties and additional injuries, particularly multiple and craniocerebral trauma [1, 3, 5-8, 11, 12, 17, 20]. Although surgical approach has been assumed to influence the development of cross-unions, no previous study has reported a specific relationship because insufficient numbers of cases were available [5, 7]. An increased incidence of synostosis apparently related to approach at our institution precipitated this investigation. The purpose of this study was to document the incidence of postoperative synostosis occurring in forearm fractures and discover factors relating to its production.

Patients and methods A retrospective review was made of all patients treated with plate osteosynthesis for forearm fractures at the University of Ulm from 1978 to 1987. A prospective study was performed from 1987 to 1989. Patients with postosteosynthetic synostosis were identified. Patients excluded were those treated primarily elsewhere, those with old fractures, and those requiring corrective osteotomies.

143

G. Bauer et al.: Radioulnar synostosis after forearm fracture osteosynthesis Table 1. Patients with radioulnar synostosis after operative stabilization Case

Age

Sex

Cause

Type of fracture

Localization

Technique

Approach

c-Bone Position of plate

Additional injury

Surgical

1.

49

M

Contusion

Forearm

Mid. 1/3

Plate rad. + ulna

2

-

Correct

-

2.

59

M

MVA

Forearm, gr.2 open

Mid. V3

Plate rad. + ulna

+

22

M

MVA

Forearm, gr. 1 open

Mid. ;/3

Plate rad. + ulna

Rad. plate dorsouln. Rad. plate dorsouln,

Polytrauma

3.

1, Boyd modified 1, Boyd

4.

21

M

MVA

Forearm, gr. 2 open

Prox. 1/3

Plate rad. + ulna

1, Boyd

-

Correct

Polytrauma

5.

22

M

MVA

Forearm

Prox. 1/3

Plate rad. + ulna

1, Boyd

-

Correct

Polytrauma

6.

44

F

MVA

Forearm

Prox. 1/3

Plate rad. + ulna

1, Boyd

+

Correct

Polytrauma

+

Correct

-

+

Acromiocl. burst

7.

72

F

Fall

Forearm, gr. 1 open

Dist. 1/3

Plate rad.

1

8.

19

M

MVA

Radius, gr. 2 open

Prox. ;/3

Plate rad.

1, atyp. via wound

-

Correct

Initial n. rad. lesion

9.

27

M

Bike accident

Ulna, rad. collum fracture

Prox. 1/3

Plate ulna

1

-

Correct

Polytrauma

10.

17

F

MVA

Monteggia

Prox. 1,~

Plate ulna

1, Boyd

-

Correct

Concussion

MVA

Radius (Galeazzi)

Prox. 1/3

Plate rad.

1

-

Correct

Polytrauma

11.

67

F

MVA, motor vehicle accident Table 2, Complications following 167 forearm fractures treated by internal plate fixation Pseudarthrosis Radioulnar synostosis Refracture Nerve lesion Infection Compartment syndrome Plate broken

15 (9%) 11 (6%) 5 (3 %) 3 (2%) 2 (1%) 1 (0.6%) 1 (0.6%)

Evaluation was by chart review, radiography, and physical examination. The average patient age at the time of injury was 31.9 years. There were 115 cases of closed (69.7%) and 52 of open (31.3%) fractures. In 89 cases, both bones of the forearm were involved (53.3%), while there were 40 isolated radial fractures (24%) and 38 isolated ulnar fractures (22.7%). The fracture locations in the forearm were: 64.7% midshaft, 29.3% distal, and 11.4% proximal.

Osteosynthesis Plate osteosynthesis was used to stabilize 89 fractures of both bones. A single plate was applied in 12 cases: 9 radii and 3 ulnae. In 38 of the 40 isolated radius fractures, immediate plate osteosynthesis was performed. Two open fractures (1 grade 2 and 1 grade 3) were treated initially with external fixation. Later, plate osteosynthesis and supplemental bone graft was performed. All 38 fractures of the ulna were stabilized immediately by plate osteosynthesis. In 22 cases, bone graft was added. This group was made up of 13 two-bone fractures, 3 isolated radial and 6 isolated ulnar fractures. A corticocancellous graft was used in 4 cases.

Fig. l a , b. Patient 1. a Fracture of both bones of the forearm, b Cross-union 14 months after plate osteosynthesis Results

Surgical approach In 65 of the 89 two-bone fracture cases, two approaches were used, while the Boyd approach was used in 24 cases [4]. All isolated fractures were treated with a single approach.

T h e r e w e r e 11 c a s e s ( 6 . 6 % ) o f r a d i o u l n a r s y n o s t o s i s , six o c c u r r i n g in c l o s e d f r a c t u r e s a n d f i v e in o p e n ( T a b l e s 1, 2). S e v e n o f t h e s e c a s e s w e r e o f t w o - b o n e f r a c t u r e s (Fig. 1), w h i l e t h e r e w e r e t w o i s o l a t e d r a d i a l a n d t w o i s o l a t e d

144

G. Bauer et al.: Radioulnar synostosis after forearm fracture osteosynthesis

Fig. 2a-c. Patient 4. a Fracture of both bones of the forearm and distal fracture of the humerus, b Two days after plate osteosynthesis, c Cross-union 4 months after plate osteosynthesis

ulnar fractures. Six of the seven two-bone fractures were treated with two plates; in the last, an open fracture, the radius was plated and the ulna stabilized with minimal osteosynthesis. In five of the six cases treated with two plates the Boyd approach was used, while in the seventh, despite treatment via two approaches, there was considerable soft-tissue trauma (Fig. 2). In the two synostoses involving isolated radial fractures, one occurred in an open grade 2 fracture in the proximal third of the bone, treated through the dorsal wound, and the other was in a d o s e d proximal-third fracture stabilized via a modified Boyd approach. The two ulnar fractures resulting in synostosis occurred after

a Monteggia fracture and a proximally located fracture. One of these patients had multiple trauma; the other, who had significant soft-tissue damage, was treated via the Boyd approach. Six cross-unions were located in the proximal third of the shaft, four in the midthird and only one in the distal third.

Discussion Various factors are considered crucial in the formation of a cross-union after forearm fractures. The proximal third of the shaft, where radius and ulna are in close proximity, seems to be most at risk [6, 20], particularly if combined fractures are located at the same level [1, 20]. Our results confirm this observation: 55% of the crossunions were noted after fractures in the proximal third.

Forearm fracture (n = 89)

,t

1

1 approach, Rad. and uln. plate (n = 12)

2 approaches, rad. and uln. plate (n = 65)

Ulna fractures (n = 38)

Radius fractures (n = 40)

Cross-uniOn(n = 2)

Cross-uniOn(n = 2)

1 approach, Rad. or uln. plate (n = 12)

l

Cross-union

]

Cross-union

Cross-union

(n = 1)

I

(n = 5)

(n = 1)

Fig. 3. Incidence of post-traumatic radioulnar synostosis after osteosynthesis of forearm fractures

[

G. Bauer et al.: Radioulnar synostosis after forearm fracture osteosynthesis Severe local t r a u m a has also been implicated as the critical factor producing synostosis. Some authors suggest an increased risk after open fractures in the presence or absence of infection (3, 6-8). Injury of the interosseous m e m b r a n e , especially with fiber rupture parallel to its course, m a y also be important [3, 8, 14, 19, 20]. Benjamin [2], Brady and Jewett [6], and Vince and Miller [17] indicate a significant increase in fracture h e m a t o m a s involving both radius and ulna. A higher incidence of synostosis has also been observed in polytraumatized patients as well as those with craniocerebral injury [8, 15, 16]. Additionally, technical errors including insufficient stabilization, delayed surgery, cast immobilization after plate osteosynthesis, faulty plate location, screws projecting into the interosseous gap, primary corticocancellous grafting - especially with graft/interosseous m e m b r a n e contact - seem to increase the risk of crossunion [2, 5, 7-10, 14]. The majority of our patients with two-bone fractures were treated with double plates. A distinct difference in the incidence of cross-union was related to the choice of approach (Fig. 3). Of our 65 cases treated via two approaches, only one with concommitant soft-tissue injury - developed a synostosis. H o w e v e r , in 5 of the 12 cases in which both radius and ulna were plated via the Boyd approach, a cross-union resulted. Only 1 synostosis occurred in the 12 two-bone fractures treated with one plate through a single approach. These results confirm observations m a d e by other authors [5, 7, 17] regarding the influence of surgical approach on the formation of subsequent cross-union. In groups of patients comparable with respect to soft-tissue damage, additional injuries, and the method of osteosynthesis used, synostosis occurred far m o r e frequently after the Boyd approach than after separate approaches to the radius and ulna. Owing to extensive soft-tissue exposure, development of radioulnar h e m a t o m a , risk of interosseous damage, and occasional malpositioning of the dorsal plate, the Boyd approach seems to increase the risk of postosteosynthetic synostosis. Therefore, particularly in the treatment of fracture of both bones, separate approaches to the radius and the ulna should be chosen and the Boyd approach avoided.

145

References

1. Anderson LD, Sisk DT, Tooms RE, Park WI (1975) Compression-plate fixation in acute diaphyseal fractures of the radius and the ulna. J Bone Joint Surg 57 [Am] : 287-297 2. Benjamin A (1976) Injuries of the forearm. In: Wilson JN (ed) Watson-Jones fracture and joint injuries, 5th edn. Churchill Livingstone, Edinburgh, pp 666-726 3. Botting TDJ (1970) Posttraumatic radio-ulna cross union. J Trauma 10:16-24 4. Boyd HB (1940) Surgical exposure of the ulna and proximal third of the radius through one incision. Surg Gynecol Obstet 71 : 86 5. Bradford CH, Adams RW, Kilfole RM (1953) Fractures of both bones of the forearm in adults. Surg Gynecol Obstet 96 : 240-244 6. Brady LP, Jewett EL (1960) A new treatment of radio-ulnar synostosis. South Med J 53 : 507-512 7. Breit R (1983) Posttraumatic radioulnar synostosis. Clin Orthop 174:149-152 8. Garland DE, Dowling V (1980) Forearm fractures in the headinjured. Adult Cfin Orthop 176 : 190-196 9. King RE (1984) Fractures of the shafts of the radius and ulna. In: Rockwood CA, Wilkins KE, King RE (eds) Fractures in children. Lippincott, Philadelphia, pp 301-362 10. Kt~sswetter W, Hirasawa Y, Quintus M (1982) Die Membrana interossea antebrachii - Leitschiene ffir die Brtickenkallusentwicklung. Z Orthop 120 : 450-451 11. Lukas L, T6rtely E (1976) Komplikationen nach Verplattung yon Unterarmbrttchen. Aktuel Traumatol 6 : 221-225 12. Moed BR, Kellam JF, Foster RJ, Tile M, Hansen ST (1986) Immediate internal fixation of open fractures of the diaphysis of the forearm. J Bone Joint Surg [Am] 68 : 1008-1017 13. Patric J (1946) A study of supination and pronation, with especial reference to the treatment of forearm fractures. J Bone Joint Surg [Am] 28 : 737-748 14. Sch6ttle H, Jungbluth KH, Sch6ntag H (1978) Posttraumatische Weichteilverkn/3cherungen am Unterarm. Unfallheilkunde 132 : 436-439 15. Stern P, Drury W (1983) Complications of plate fixation of forearm fractures. Clin Orthop 175 : 25-29 16. Tibone J, Sakimura J, Nickel VL, Hsu JD (1978) Heterotopic ossification around the hip in spinal cord injured patients. J Bone Joint Surg 60: 769-775 17. Vince KG, Miller JE (1987) Cross-union complicating fracture of the forearm. I: Adults. J Bone Joint Surg [Am] 69 : 640-653 18. Vince KG, Miller JE (1987) Cross-union complicating fracture of the forearm. II: Children. J Bone Joint Surg [Am] 69 : 654661 19. Watson FM Jr, Eaton RG (1978) Post-traumatic radio-ulnar synostosis. J Trauma 18 : 467-468 20. Weigand H, Ritter G (1978) Die operative Behandlung von Synostosen nach Unterarmfrakturen. Unfallheilkunde 132: 439-441 21. Zilch H (1979) Ergebnisse der operativen Behandlung des Brtickenkallus durch Silastic-Membran-Interposition. Handchirurgie 11:209-211