557

Viktor Philipe

M. Metz, MD Saffar, MD

Sylvia

#{149}

M. Schimmerl,

Wide Scapholunate In Lunotriquetral A Normal Variant?’ The radiologic appearances of 70 lunotriquetral coalitions in 52 patients were evaluated to determine whether a wide scapholunate joint space in subjects with this congenital abnormality reflects a scapholunate ligament disruption or is a normal variant. When the middle of the scapholunate joint space was larger than the capitolunate or third carpometacarpal joint space widths, it was considered to be abnormally wide. In 32 of 70 wrists (46%), a wide scapholunate joint space was detected. Results of instability radiographic series (n = 28) and arthrography (n = 11) were normal with respect to the scapholunate ligament in all cases, but the scapholunate joint space was markedly widened in six cases (55%) in which arthrography was performed. Arthroscopy, performed in one case, showed an intact scapholunate ligament. Because of the high prevalence of a wide scapholunate joint space and because of negative arthrographic and arthroscopic examinations, the authors conclude that widening of the scapholunate joint space is a normal variant that is common in patients with lunotriquetral coalition. Index

terms:

Bones,

Joints, abnormalities, ties, 434.13

abnormalities, 434.13

Wrist,

#{149}

4332.143 abnormali-

MD

Joint Coalition:

1993;

I

From

the Radiological

Austria

(V.M.M.,

Vienna S.M.S.);

Department School,

Mallinckrodt

of Radiology, Washington University Medicine, 510 S Kingshighway Blvd. MO 63110-1076 (LAG.); the Division

of SurgiVienna, Institute

School

of

St Louis, of Orthopedic Surgery, University of Texas, Galveston (S.F.V.); and Franklin Surgery Center, Institute Francais de la Main, Paris, France (P.S.). Received December 4, 1992; revision requested January 1 1, 1993; revision received February 5; accepted February 17. Address reprint requests to LAG. e RSNA, 1993

F. Viegas,

evaluated. in ii

coalition between two or more carpal bones is a well known abnormality, with the most common variety being coalition between the lunate and tnquetrum (1-3).

The

radiologic

different types tions as isolated syndrome

appearances

have

ature

(4-8).

of

of lunotriquetral coalientities or as part of a

of congenital

tions

been

malforma-

described

Variations

MD

in the in the

liter-

width

of

Arthrography

wrists,

and

was performed

arthroscopy

of the

radio-

carpal joint was performed in one. The type of lunotriquetral coalition was determined according to the scheme described by Minaar (5). The width of the scapholunate joint space was measured by using a metric lens and was considered to be abnormal when the middle portion of the scapholunate joint space was larger than the capitolunate joint space width

and/or

the third

carpometacarpal

joint

the scapholunate joint space in patients with lunotriquetral coalitions, however, have not previously been described. Since lunotriquetral coali-

space

tions are most commonly discovered as incidental findings during radio-

of coalition type (n = 70) 10 fibrous or cartilaginous coalitions (Minaar type I), 37 incomplete bony coalitions with a distal notch at the site of the usual division (Minaar type 11), and 23 complete bony coalitions without a notch (Minaar type Ill). Bilateral lunotriquetral coalitions were of the complete or incomplete bony variety in 13 patients and of the fibrous or cartilaginous variety in two patients. The scapholunate joint space was definitely considered abnormally widened in 32 of 70 wrists (46%) (Fig 1) and was of a normal width in 33

space

reflects

a scapholunate

disruption lunotnquetral

variant

in

coalition.

MATERIALS

AND

METHODS

(47%).

In this retrospective study, radiographs of the wrists of 52 patients (25 males, 27 females; mean age, 35 years; age range, 16-67 years) with lunotriquetral coalitions

evaluated. were

Radiographs

available of only

of both

in 18 patients, one

wrist

and

were

lunotriquetral

avail-

coali-

tions could therefore be evaluated. In most cases, patients had been referred for evaluation of subacute or chronic pain of the forearm, wrist, or hand, with or without a history of trauma. One patient with Holt-Oram syndrome

and one patient

whose

mother

tionably taken medication during nancy were referred for evaluation various bone malformations.

In all cases, views

eral) were graphic

radiographs

(posteroanterior,

available.

series

in 15 wrists

had quespregfor

in at least oblique,

and

three tat-

An instability radioand a bone scan

in 28 wrists were

available,

and

these

RESULTS Evaluation

ligament

or is a normal

width.

showed

graphic examinations of the forearm, wrist, and hand, a widening of the scapholunate joint space may reflect a normal variation of the scapholunate ligament or the scapholunate articulation. The aim of this study was to determine whether the radiographic feature of a wide scapholunate joint

radiographs

Medical

Steven

#{149}

Space

able in 34. Seventy

cal Disciplines,

MD

‘4#{149}__

were

188:557-559

A. Gilula,

(ONGENITAL

wrists Radiology

Louis

#{149}

were

In five

cases

(7%),

an

exact

evaluation of the scapholunate joint space was not possible because the joint space was not well profiled on the available radiographs. The instability series, consisting of 11-17

views

of each

wrist

and

per-

formed in 28 wrists, did not demonstrate any instability, increase of the width of the scapholunate joint space, or abnormal motion at the scapholunate joint. Performance of the instability series under fluoroscopic controt allowed the scaphotunate joint to be precisely profiled. Results of bone scanning (n = 15 wrists) were normal with respect to the lunotriquetral coalition in 11 cases. In four cases, marked increased tracer uptake was evident at the site of the lunotriquetral coalition. In all of those four cases, the coalition was fibrous or cartilaginous

throughout

the

entire

joint,

one

had

had

a history

patient

trauma

to the

a bilateral

wrist.

fibrous

11 wrists)

=

spect

to the

those

cases

joint

space

patient

normal

with

scapholunate the

re-

ligament

although

(55%),

was

with

arthrography

were

in all 11 wrists,

only

of

coalition and no had marked tracer

history of trauma uptake bilaterally. Results of wrist

(n

One

and

in six of scapholunate

moderately

to mark-

edly widened at radiography and therefore suspect for a defect of the scapholunate ligament prior to arthrography (Fig 2). Arthroscopy of the radiocarpal joint of the right wrist

of a patient and bilateral space ment

with a bilateral coalition wide scapholunate joint

showed the scapholunate to be intact (Fig 3).

liga-

joint space, the scapholunate joint space must be wider to compensate and allow the proximal carpal row to fit better and function normally with the distal carpal row and the radius. In some cases (Fig 2), this theory is supported by the absolute thickening of cartilage on opposing surfaces of the scaphoid and lunate bones. This may be important, since lunotriquetral coalitions are usually incidental findings in patients referred for radiographic examination of the wrist due to trauma. In such cases, a wide scapholunate joint space may be only a normal variant and not a pathologic finding. Controversy exists as to whether lunotriquetral coalitions or failures of segmentation are subject to fracture (1,5,6) or if they strengthen the wrist

(16). In none of our patients who had sustained particularly severe injuries to the distal forearm, wrist, or hand (eg, fractures of the scaphoid or distal radius) did a fracture of the lunotriquetral coalition occur. One patient with a fibrous coalition and history of wrist trauma, however, had persistent pain at the site of the lunotriquetral area since that trauma. Although no definite fracture line at the lunotriquetral joint could be detected at plain radiography, uptake at bone scanning was high at that particular site, which could have been due to a

DISCUSSION Congenital lunotriquetral coalition is a rare abnormality with an mcidence of 0.1% in whites, 1.6% in black Americans, and up to 9% in black Africans (6,9). It is reported twice as frequently in women (6,9). It may occur as an isolated entity or as part of a syndrome and may show a familial pattern (2,5,10). It is caused by a fail-

ure of separation the carpal bones Different

or segmentation (11-13).

radiographic

of

patterns

of

lunotriquetral coalitions (5,7,14) with or without rounded darker areas in the subarticular region of the incomplete lunotriquetral coalitions and with (10) or without (5,7,15) have been

erature.

In none

symptoms reported in the

of these

lit-

references,

however, was the width of the scapholunate joint space in patients with lunotriquetral coalitions discussed. Of the 70 wrists with lunotriquetral coalition, 32 (46%) had a markedly

widened

scapholunate

joint

Figure

2.

Midcarpal

a 49-year-old Figure

1.

Radiograph

ofleft

wrist

of a 29-

coalition

year-old man with a complete lunotriquetral coalition (wide arrow) without evidence of a distal notch at the site of the usual division (Minaar type III). The prominent widening of the scapholunate joint space is evident from the scapholunate joint (narrow arrows) being much wider than the capitolunate joint (arrowheads).

and

nate joint

nate

joint

with

a markedly

space.

(arrowhead) side of the

arthrogram

woman The

obtained

widened

scapholu-

scapholunate

is intact. The contrast medium

ligament

cartilage in the

is thicker

than

the other

by the

contrast

medium

as outlined

throughout

the midcarpal

nication

from

pal joint

was evident.

the

in

a lunotriquetral

joint.

midcarpal

on either scapholu-

cartilage, evident

No commu-

to the

radiocar-

space.

This condition was bilateral in eight patients (16 wrists). Arthrography was performed in six wrists, and no contrast material leakage through the scapholunate ligament was identified (Fig 2). Also, arthroscopy of the radiocarpal joint in the patient with a wide scapholunate joint space showed the scapholunate ligament to be completely intact (Fig 3). For these rcasons and because of the high prevalence (46%) of a wide scapholunate joint space in our patients with lunotriquetral coalition, it seems likely that scapholunate joint widening in such patients may be a common normat variant rather than a pathologic feature. It is theoretically possible that, because of loss of lunotriquetral

558

Radiology

#{149}

a. Figure coalition throscopic (arrows) scaphoid, ligament

3.

(a) Posteroanterior (arrow) image blends

radiograph

obtained

b. in a 28-year-old

man

with

a lunotriquetral

and marked widening of the scapholunate joint space (arrowheads). of the radiocarpal joint in the same patient. An intact scapholunate with the cartilage. There is no defect or perforation in the ligamcnt. L lunate, R = distal radius, V volar radiolunate ligament, [ -- syfloViUifl of Testut.

(b) Arligarnc;it S

August

md

1993

fracture of the fibrous coalition. In other patients who had no history of trauma, however, uptake was also increased at this site. In our opinion, it is unlikely that complete bony fusion between the lunate and triquetrum is a weak point. It seems likely, however, that incomplete or fibrous coalitions may be weak at this point and therefore theoretically can frac-

2.

It has been reported with congenital carpal functional impairment agree

with

none

of the

series

performed

evidence minished

those

instability

that a wrist fusions has no (6,7). Our rereports,

3.

in our

study

of carpal instability range of motion.

4.

188

#{149} Number

2

R.

A survey

J Bone Joint

Poznanski congenital

AK, HoltJF. malformation

10. JM.

The

develop-

of carpal and tarsal Surg [Am] 1953;

6.

7.

8.

in AJR

fusion of the lubones in the South AfriJoint Surg [Br] 1952; 34:

45-48. Cockshott WP. Carpal fusions. 89:1260-1271. Szaboky GT, MullerJ, MelnickJ,

R. Anomalous and triquetrum.

or di-

The carpals syndromes.

1971; 112:443-459. Minaar AB. Congenital

nate and triquetral can Bantu. J Bone

9.

Volume

O’Rahilly

triquetral-lunate fusion. pol 1971; 34:431-434.

Clin Radiol

35:626-639.

showed U

coalition.

1974; 25:261-266. Hughes PCR, Tanner

anomalies.

since

radiographic

Carpal

ment of carpal bone fusion as seen in serial radiographs. BrJ Radiol 1966; 39:943-949.

5.

ture.

suits

References 1. Cope JR.

AJR

1963;

Tamburro

fusion between the lunate J Bone Joint Surg [Am]

ii.

12.

14. 15. 16.

Anthro-

Simmons BP, McKenzie WD. Symptomatic carpal coalition. J Hand Surg [Am] 1985; 10:190-193. Resnik CS, Gizzard JD, Simmons BP, Yaghmai I. Incomplete carpal coalition. AJR 1986; 147:301-304. Garn SM, Burdi AR, Babler WJ. Prenatal origins of carpal fusions. Am J Phys An-

thropol 13.

Am J Phys

Sledge

imental Orthop Carlson Skeletal

1976; 45:203-208. CB.

Some

morphologic

and

exper-

aspects of limb development. Clin Rel Res 1966; 44:241-264. DH. Coalition of carpal bones. Radiol 1981; 7:12.5-127.

CurrJF. Congenital fusion of lunate triquetrum. BrJ Surg 1946; 34:99-100. KollarJ, Arany L. Die lunatotriquetrale

and

verschmelzung.

1986;

Fortschr

Roentgenstr

144:364-366.

1969; 51:1001-1004. Schacherl M, Schilling F. Zur differentialdiagnose erworbener und angeborener carpalsynostosen. ROFO 1965; 102:68-77.

Garn SM, Frisancho AR, Poznanski AK, SchweitzerJ, McCann MB. Analysis of

Ralinlgrrn,

.

Q