Vol. 8, No. I

January 1983

thrography as a method of diagnosing soft tissue injuries

of the wrist. J Trauma 19:376-80. 1979

8. Goldman AB: III Freiberger RH. Kaye 11: Arthrography. New York, 1979 , Appleton-Century-Crofts, pp 277-94

9. Arndt RD, Horns JW. Gold RH . Blaschke DD: Clinical

arthrography. Baltimore . 1981, The Williams & Wilkins

Co. pp 159-82 10. Nel son CL. Burton R[: Upper extremity arthrography.

Clin Orthop 107:62-72, 1975

[I. Andren L. Eiken 0: Arthrographic studies of wrist gan­

glions. J Bone Joint Surg [Am] 53:299-302. 1971

12. Nel son CL. Sawmiller S, Phalen GS: Ganglions of the wrist and hand. J Bone loint Surg [Am] 54: 1459-64.

1972 13 . Martinek H: Zur Arthrograhie des handgelenks und ihrer

unfallchirurgischen bedenutung. Fortschr Geb Rontgen-

Arthrography of the wrist

str Nuklearmed Erganzungband 127:458-62, [977

14. Hall FM: Epinephrine enhanced knee arthrography.

Radiology 111:215. 1974 15 . Weston WI, Kelsey CK: Functional anatomy of the

pisicuneiform joint . I Radiol 46:692-94. 1973

16. Lewis 01: The development of the human wrist joint

during the fetal period. Anat Rec 166:499-16, 1970

17. Mikic ZD: Age changes in the triangular fibrocartilage of

the wrist joint. J Anat 126:367-84, 1978

18. Palmer AK, Werner FW: The triangular fibrocartil age

complex of the wrist-Anatomy and function. 1 HAND

SURG 6:153-62. 1981

19. Palmer AK, Glisson RR. Werner FW: Ulnar variance

determination. J HAND SURG 7:376-9 , 1982

20. Taleisnik J: Carpal bone injuries. Clin Orthop 149:73-82 .

1980

The role of radiography and computerized tomography in the diagnosis of subluxation and dislocation of the distal radioulnar joint

The diagnosis of an isolated subluxation or dislocation of the distal radioulnar joint (DRUJ) may be extremely difficult to make from the standard radiographic examination. Radiographs and computerized tomographic (CT) scans of cadaver wrists were used to evaluate subluxation and dislocation of the DRUJ. Both subluxation and dislocation could be accurately diagnosed from a true lateral radiographic projection of the wrist with the forearm in neutral rotation. Minimal supination or pronation of the forearm led to inaccurate diagnosis. A single CT scan through the DRUJ was diagnostic for subluxation and dislocation in all positions of forearm rotation. WJ'ist pain, plaster immobilization, or suboptimal wrist positioning may make it impossible to obtain a perfect lateral view of the wrist, thereby precluding the radiographic diagnosis of DRUJ sublux­ation and dislocation. In this instance, a single CT scan through the DRUJ is recommended. (J HAND SURG 8:23-31, 1983.)

David E. Mino, M.D., Andrew K. Palmer, M.D ., and E. Mark Levinsohn, M.D., Syracuse, N. Y.

The distal radioulnar joint (DRUJ) is oc­casionally subjected to isolated traumatic subluxation or dislocation.·-7 Derangement of this articulation may

From the Departments of Orthopedic Surgery and Radiology, Upstate Medical Center. Syracuse, N. Y.

Received for publication March 24, 1982; accepted in revised form July 21. 1982.

Reprint requests: Dr. Andrew K. Palmer, Department of Orthopedic Surgery. Upstate Medical Center, 750 E. Adams SI., Syracuse. NY 13210.

be associated with numerous other conditions, includ­ing ulnar styloid fracture , Colles fracture,8 radial diaphyseal fracture,9 radial head fracture or excision!O triangular fibrocartilage complex injury, II and dispro­portionate radioulnar length.·

Subluxation or dislocation of the distal radioulnar joint may initially go undiagnosed. The difficulty in diagnosis frequently lies in the inability to radio­graphically confirm subluxation or dislocation of this articulation.

0363-5023/83/010023+09$00.9010 © 1983 American Society for Surgery of the Hand THE JOURNAL OF HAND SURGERY 23

24 Mino et al.

)( -ray source

\J,

fu II pronation full

supination

Fig. 1. The upper extremity in the standardized neutral posi­tion in the adjustable frame showing the five rotational posi­tions examined. The x-ray source. specimen. and x-ray plate remain constant with the elbow in 90° flexion. Reproducible positions from full supination to full pronation for each ex­tremity are maintained with the lockable yolk.

This study was undertaken to evaluate the relative value of routine radiography and computerized tomog­raphy (CT) in the diagnosis of distal DRUJ subluxation and dislocation.

Materials and methods

Three cadaver upper extremities, transected at the midhumerus level, were mounted in an apparatus that was designed to secure the specimen in 90° of flexion at the elbow, with the forearm and wrist parallel to the x-ray table . The humerus was positioned 90° from the x-ray table in both the sagittal and coronal planes . A Steinman pin was inserted transversely through the second through fifth metacarpals, securing the hand within a circular sleeve machined to rotate within a lockable yoke (Fig. I). This permitted reproducible forearm positioning. The x-ray beam was directed per­pendicular to the wrist from above with the x-ray plate placed beneath the plexiglass apparatus for all views (Fig. 1) . A standardized relationship between x-ray source, specimen, and x-ray plate was maintained . All specimens were examined radiographically and with

The Journal of HAND SURGERY

CT scans in neutral rotation, 45° supination, full supi­nation. 45° pronation. and full pronation.

Initially, each specimen was viewed with the DR UJ reduced and with all stabilizing ligaments intact. All supporting soft tissue structures supporting the DRUJ were then excised. Radiographs and CT scans were obtained in each of the above positions of rotation, with each specimen placed in 50% palmar subluxation, pal­mar dislocation, 50% dorsal subluxation, and dorsal dislocation (Fig. 2) . The positioning for subluxation and dislocation was performed under direct visualiza­tion and maintained by a transfixing Kirschner wire between the distal radius and ulna.

The CT scanner was a Delta Scan 2020 (Technicare Corp. , Solon. Ohio) . A gantry diameter of 25 cm was selected. Images were photographed at a center setting of 400 and a window setting of 1000 for optimal bone visualization. One-centimeter sections were obtained in the transverse plane starting 2 cm proximal to the DRUJ and extending 2 cm distal to this joint.

A fourth cadaver upper extremity, positioned iden­tically in the apparatus, was analyzed with radiographs with the wrist in neutral, 10° supination and 10° prona­tion . Cross-table lateral projections of the wrist were obtained in full supination and pronation . Radiographs in these five positions of rotation were obtained with the DRUJ reduced, 50% palmar subluxated, palmar dislocated, 50% dorsal subluxated, and dorsal dislo­cated. This was performed to determine if slight rota­tion from neutral, or if " lateral" views of the wrist in supination and pronation were equivalent to lateral roentgenograms in the neutral position .

Results

Radiographs. With the upper extremity positioned in neutral rotation an exact lateral view of the wrist showed the following radiographic relationships in all specimens: A complete superimposition of the lunate, proximal pole of the scaphoid, and triquetrum was present, allowing no delineation between the proximal borders of these bones (Fig . 2) and the radial styloid was centered over the distal radius. Even 10° of supi­nation or pronation altered these relationships. Slight supination allowed clear visualization of the triquetral­pisiform articulation (Fig . 3). Slight pronation pro­duced individual delineation of the proximal carpal row bones (Fig. 4). These relationships were consistent in all specimens whether the distal radioulnar joint was reduced, subluxated, or dislocated and are illustrated in Fig. 5.

Using these criteria, while in neutral rotation both

Vol. 8, No.1 January 1983

a.

b.

c. d.

Diagnosis of distal radioulnar joint injuries 25

Fig. 2. The lateral view of the wrist in the neutral position is shown in dorsal dislocation (a), dorsal subluxation (b), palmar subluxation (c), and palmar dislocation (d) of the ulna(u) on the radiocarpal mass. Complete superimposition of the proximal pole of the scaphoid (5), lunate (L), and triquetrum is seen. The radial styloid is centered over the proximal carpus. With the wrist in the neutral position, radiographic interpretation of ulnar subluxation and dislocation is possible.

Fig. 3. With 10° supination. the triquetral-pisiform articulation is clearly visualized. The radiocarpal alignment is altered significantly from neutral rotation . Dorsal dislocation (A) appears subluxated, while dorsal subluxation (B) appears reduced. Palmar subluxation appears dislocated (C). Only palmar dislocation (D) is accurately interpretable.

26 Mino et al. The Journal of

HAND SURGERY

Fig. 4. With 10° pronation, the radiocarpal alignment is significantly altered from neutral rotation. Individual delineation of the proximal carpal row is seen. While dorsal dislocation (A) is accurately interpretable, dorsal subluxation (B) appears dislocated and palmar subluxation (C) appears re­duced, while palmar dislocation (D) appears subluxated.

b. 100 pronation

---

Fig. 5. From the neutral position slight rotation alters the radiocarpal mass alignment. With 10° of supination (a) or pronation (b), individual delineation of the proximal pole of the scaphoid, lunate, and triquetrum occurs. Ten degrees of supination allows visualization of the triquetrum (T)-pisiform

(P) articulation. Rotation from the neutral position made accurate radiographic interpretation of subluxation and dislocation impossible. R, radius; U, ulna; S, scaphoid; L, lunate; C, capitate.

palmar and dorsal subluxation and dislocation of the DRUJ was determined radiographically. Fig. 6 shows palmar and dorsal subluxation and dislocation with the wrist in neutral rotation.

With 10° of supination from the neutral position, dorsal dislocation appeared subluxated and dorsal sub­luxation appeared reduced. Palmar dislocation could be

determined while palmar subluxation could not (Fig. 3). With 10° of pronation from the neutral position, dor­sal dislocation was interpretable and dorsal subluxation appeared dislocated. Palmar subluxation appeared re­duced, while palmar dislocation appeared only sublux­ated (Fig. 4).

Cross-table lateral radiographs in full supination and

Vol. 8, No. I January 1983 Diagnosis of distal radioulnar joint injuries 27

Fig. 6. Palmar and dorsal subluxation and dislocation of the distal radioulnar joint in the neutral position. A, dorsal dislocation; B, dorsal subluxation; C, reduced; 0, palmar subluxation; E, palmar dislocation.

Fig. 7. In full supination, cross-table lateral radiographs give inaccurate detail of ORUJ congru­ency. The distal ulna appears to be subluxated dorsally with the ORUJ reduced (C). While dorsal dislocation (A) and dorsal subluxation (B) are interpretable, palmar subluxation (D) and palmar dislocation (E) are not. Cross-table lateral radiographs with the wrist in full supination are not equivalent to the neutral positioned wrist.

full pronation were not equivalent to a lateral view in neutral rotation. The distal ulna appeared subluxated in both cross-table lateral projections with the DRUJ re­duced (Figs. 7, c and 8, c). Lateral radiographs in full supination made diagnosis of palmar subluxation and

dislocation impossible (Figs. 7, d and 7, e). Lateral radiographs in full pronation made accurate diagnosis of dorsal subluxation and dislocation impossible (Fig. 8). These findings were due to the oblique radiographic projection of the distal radius and ulna in supination

28 MillO et al. The Journal of

HAND SURGERY

Fig. 8. In full pronation. cross-table radiographs project inaccurate detail of DRUJ congruency. The distal ulna appears to be subluxated palmarward with the DRUJ reduced (C). Accurate diagnosi s of dorsal dislocation (A) and dorsal subluxation (B) is not possible. Both palmar subluxation (D) and palmar dislocation (E) appear dislocated.

Fig. 9. CT sections of a right DRUJ reduced from full supination (A), 45° supination (B), neutral rotation (C). 45° pronation (D), and full pronation (E). The ulnar head lies within the sigmoid notch of the radius. Pronation causes a distraction between the ulna and radius . but the ulna remains reduced . If two lines are constructed as described in Fig. 12. the ulnar head lies between them .

and pronation altering the distal radial, ulnar, and car­pal relationships previously described. This would be further compounded by the individual range of full supination and pronation that is possible for a given wrist.

CT scan. The CT scan projects a transverse section of the DR UJ. The semicircular convex ulnar head can be seen as it articulates in the sigmoid notch of the distal radius. A CT scan section taken through the DRUJ projecting the ulnar styloid process, the sigmoid notch, and Lister's tubercle gave the best visualization

of the DRUJ (Figs. 9, 10 , and 11). Sections proximal and distal to the DRUJ were not diagnostic of DRUJ congruity.

In all positions of rotation, the distal ulna con­gruently articulated within the sigmoid notch of the distal radius when the DRUJ was reduced. By con­structing a line through the dorsal ulnar and radial bor­ders of the radius and a second line through the palmar ulnar and radial borders of the radius, the reduced ulnar head lies between these lines (Fig. 12). With progres­sive palmar or dorsal subluxation and finally disloca-

Vol. 8, No. I January 1983

~ ..• \:,,~

• A

Diagnosis of distal radioulnar joint injuries 29

Fig. 10. CT sections through a right wrist with the ORUJ dorsally subluxated. Radioulnar congru­ency is lost. with the ulna shifting dorsally in all positions of rotation from full supination (A), 45° supination (B), neutral rotation (C), 45° pronation (D), and full pronation (E).

Fig. 11. A CT scan of a right wrist with dorsal dislocation of the ORUJ. Radioulnar congruency is absent. In full supination (A), 45° supination (B), neutral rotation (C), 45° pronation (D), and full pronation (E) dorsal dislocation is accurately diagnosed. The versatility of the CT scan in diagnos­ing ORUJ incongruency, independent of rotational position , is shown.

tion, the ulnar head becomes increasingly displaced from the radial sigmoid notch crossing each respective line.

With palmar subluxation, an increased distance is found to occur between the dorsal border of the sigmoid notch of the radius and ulnar head. Dorsal subluxation similarly creates an increased distance between the palmar aspect of the sigmoid notch and the ulnar head . Unlike radiographs, the CT scan gave consistently in­terpretable results in all positions of rotation tested, whether the DRUJ was reduced, subluxated or dislo-

cated. Figs. 9, 10, and II show representative CT sec­tions of the DRUJ reduced, dorsally subluxated, and dorsally dislocated in the rotational positions tested. The ulna in the reduced DRUJ was noted to trans locate dorsally with pronation and palmarward with supina­tion, but the ulna remained reduced at all times within the confines of the sigmoid notch of the radius.

Discussion

Various authors have suggested radiographic criteria to assess the relationships of the distal radioulnar articu-

30 Millo et al.

b.

c.

d.

Fig. 12. A transverse section through the DRUJ as is seen by CT scan and depicting the sigmoid notch and Lister's tubercle of the radius (R). Dorsal dislocation of the ulna (a), dorsal subluxation (b), palmar subluxation (c), and palmar disloca­tion (d) are shown. A line drawn through the dorsal ulnar and radial borders of the radius shows the degree of DRUJ dorsal incongruity and a lille drawn through the palmar ulnar and radial borders of the radius shows the degree of distal radioul­nar joint palmar incongruity . U, ulna.

lation . Heiple et al. 2 state that a true lateral of the wrist is necessary for the diagnosis of DRUJ subluxation or dislocation . Snook et al. 5 note that a posteroanterior view of the wrist in full pronation normally places the ulnar styloid on the medial side of the distal ulna , but in subluxation, the styloid appears in the center to the radial side of the distal ulna. They feel that a lateral view is nondiagnostic for subluxation . Bowers12 states that since the distal radioulnar articulation is one that can be rotated and moved in space, a standard tech­nique for accurate assessment and sequential follow-up for comparison is necessary. 12 He suggests the ulnar styloid as a reference point. A lack of standardized technique in wrist positioning is a continuous problem that can be found in the radiology literature as well .13

Abduction of the humerus with compensatory rota­tion of the forearm to obtain a "lateral " projection of the wrist produces variability of the DRUJ that makes sequential reproducible radiographic studies unpredict­able. With this in mind, a standard upper extremity position was studied as described . We found that ra­diographs were diagnostic for DRUJ subluxation and dislocation if the wrist was in neutral rotation. Slight supination or pronation, however, made radiographic diagnosis inaccurate. The use of metacarpal align­ment,2. 3 triquetral-ulnar alignment,14 and ulnar styloid position5• 12 were found to be nondiagnostic for palmar

The Journal of HAND SURGERY

and dorsal dislocation. Cross-table lateral projections of the wrist in full supination and pronation were not equivalent to a lateral projection in neutral rotation and were nondiagnostic for DRUJ incongruity.

The need for accurate positioning is thus very critical for accurate radiographic determination of DRUJ sub­luxation or dislocation . This, however, is frequently not possible . Often a patient with wrist trauma is unable to place his extremity in the proper position for radio­graphs because of pain . Radiology technicians fre­quently do not use a consistent upper extremity position to obtain reproducible radiographs. Plaster immobili­zation not only prevents accurate positioning of a forearm for evaluation of the DRUJ, but also can sig­nificantly obscure detail.

The CT section gives an "end-on" transverse view of the DRUJ, showing the sigmoid notch and Lister's tubercle of the radius and the ulnar head and styloid. With increasing subluxation and eventual dislocation , proportional incongruity between the ulnar head and sigmoid notch in the respective palmar or dorsal direc­tions is seen. The position of forearm supination or pronation has been found not to effect the diagnosis of subluxation or dislocation in either a palmar or dorsal direction. Plaster casts do not obscure CT scan detail. We feel that a single CT section through the DRUJ is the simplest and most accurate means of assessment of DRUJ congruity.

Conclusions

An accurate diagnosis of DRUJ subluxation and dis­location can be made radiographically when a lateral view of the wrist is obtained in exact neutral rotation . In the clinical situation, however, a true lateral view of the wrist is often not obtainable . A single CT section through the DRUJ in any position of forearm rotation is diagnostic of subluxation or dislocation of this articula­tion and is recommended.

We thank Miss Carolyn Wiltsie and Mr. John Ruggiero for their technical assistance and Miss Janice Niezabytowski for her secretarial assistance .

REFERENCES

I . Milch H: So called dislocation of the lower end of the ulna . Ann Surg 116:282-92 , 1942

2. Heiple KG, Freehafer AA . Van 't Hof A: Isolated trau­matic dislocation of the distal end of the ulna or distal radioulnar joint . J Bone Joint Surg [Am] 44:1387-94 , 1962

3. Dameron TB: Traumatic dislocation of the distal radioul­nar joint. Clin Orthop 83:55-63, 1972

4. Morrissy RT, Nalebuff EA: Dislocation of the distal

Vol. 8, No.1 January 1983 Diagnosis of distal radioulnar joint injuries

radioulnar joint: anatomy and clues to prompt diagnosis. Clin Orthop 144: 154-8, 1979

9. Hughston JC: Fracture of the distal radial shaft. J Bone Joint Surg [Am] 39:249-64

5. Snook GA, Chrisman OD, Wilson TC, Wietsma RD: Subluxation of the distal radio-ulnar joint by hy­perpronation. J Bone Joint Surg [Am] 51:1315-23, 1969

10. Essex-Lopresti P: Fractures of the radial head with dis­tal radio-ulnar dislocation. J Bone Joint Surg [Br] 33:244-7, 1951

6. Hamlin C: Traumatic disruption of the distal radioulnar joint. Am J Sports Med 5:93-6, 1977

7. Rose-Innes AP: Anterior dislocation of the ulna at the inferior radio-ulnar joint. J Bone Joint Surg [Br] 42: 515-21,1960

1 J. Palmer AK, Werner FW: The triangular fibrocartilage complex of the wrist-anatomy and function. J HAND SURG 6:153-62,1981

12. Bowers W: III Green D. editor: Hand surgery, The C. V. Mosby Co. (In press)

8. Frykman G: Fracture of the distal radius including sequelae-shoulder-hand-finger syndrome, disturbance in the distal radio-ulnar ioint and imoairment of nerve function. Acta Orthop Scand 108 (suppl):3-153, 1967

13. Merrill V: Atlas of roentgenographic positions and stan­dard radiologic procedure. St. Louis, 1975, The C. V. Mosby Co.

Hands on Stamps

These stamps were drawn by Tremois for the International Phil­atelic Exhibition in Paris, June 11-21, 1982. The first stamp rep­resents France as a drawing hand and the second, Paris, as two sides of a face, the profile looking back to the old days and the full face looking toward the present and future. Concerning the hand, everyone may imagine what he wants. I think that the meaning can be found in the ability of the hand to make a scientific work or an artistic one. In this hypothesis, France may be represented by the hand.

lean-Francois Schuhl, M.D. Hopital-Ecole De La Croix Rouge Francaise

Chemin de fa Breteque 76230 Boisguillaume

France

THE JOURNAL OF HAND SURGERY 31