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CJS, Vol. 41, No. 2, April 1998 119

Original ArticleArticle original

THE CARPAL STRETCH TEST

Richard A.K. Reynolds, MD;* Geoffrey H.F. Johnston, MD;† Lawrence Friedman, MB BCh‡

From the Division of Orthopedics, Department of Surgery, Royal University Hospital, University of Saskatchwan, Saskatoon, Sask.

Presented at the Canadian Orthopaedic Residents’ annual meeting, Ottawa, Ont. 1989, the Canadian Society for Surgery of the Hand (MANUS) annual meeting, Calgary,Alta. 1991; as a poster at the American Society for Surgery of the Hand annual meeting, Seattle, Wash. 1989, and at the American Academy of Orthopaedic Surgeonsannual meeting, New Orleans, La. 1990

*Assistant Professor, Orthopedic Surgery, University of Southern California, Los Angeles, Calif.

†Professor of Surgery (Orthopedics) Royal University Hospital

‡Clinical Associate Professor, McMaster University Medical Center, Hamilton, Ont. Clinical Associate, Guelph University. Chief, Diagnostic Imaging, Guelph GeneralHospital, Guelph, Ont.

Accepted for publication Aug. 11, 1997

Correspondence to: Dr. Geoffrey H.F. Johnston, Department of Surgery (Orthopedics), Royal University Hospital, 103 Hospital Dr., Saskatoon SK S7N 0W8

© 1998 Canadian Medical Association (text and abstract/résumé)

OBJECTIVE: To compare the sensitivity of traditional motion studies, bone scintigraphy and radiocarpalarthrography to a “carpal stretch test,” for evaluation of dynamic dissociative carpal instability.DESIGN: Experimental study comparing the results of the tests to the findings of arthroscopy, the “gold standard.”SETTING: A university hospital-based upper extremity practice.PATIENTS: Six patients with chronic wrist pain, arthroscopically confirmed proximal row ligamentous dis-ruption and radiographs not suggestive of proximal row instability.INTERVENTIONS: The carpal stretch test: both affected and unaffected wrists were subjected to the sametesting, wherein the wrist was suspended from finger traps for 10 minutes by a 4.5-kg weight. Standard-ized posteroanterior radiographs were taken of the suspended wrists.MAIN OUTCOME MEASURES: Disruption of Gilula’s arcs I and II, and sensitivity of the carpal stretch testcompared with other investigations.MAIN RESULTS: Step deformities ranging from 2.5 to 6 mm (average 3.7 mm) were recorded in the affectedwrists and 0 to 4 mm (average 1.5 mm) in the “unaffected” wrists. The test was more sensitive than tradi-tional radiography, arthrography and scintigraphy in defining both presence and site of proximal carpalrow ligamentous tears and was almost as sensitive as arthroscopy.CONCLUSION: In patients with chronic wrist pain and dynamic dissociative wrist instability, the carpal stretchtest may prove to be a valuable screening tool for detecting ligamentous tears of the proximal carpal row.

OBJECTIF : Comparer la sensibilité des études de mouvement traditionnelles, de la scintigraphie osseuse etde l’arthrographie radiocarpienne à celle d’un «test d’étirement carpien» pour évaluer une instabilité carpi-enne dissociative dynamique.CONCEPTION : Étude expérimentale comparant les résultats des tests aux constatations découlant del’arthroscopie, «l’étalon-or».CONTEXTE : Pratique de traitement des extrémités supérieures dans un hôpital universitaire.PATIENTS : Six patients souffrant de douleur chronique au poignet, de rupture ligamentaire aux pôles proxi-maux confirmée par arthroscopie et dont les radiographies n’indiquaient pas d’instabilité des pôles proximaux.INTERVENTIONS : Test d’étirement carpien. On a soumis au même test les deux poignets, atteint et non at-teint. Le poignet est suspendu pendant 10 minutes et étiré au moyen d’un poids de 4,5 kg. On a pris desradiographies postéro-antérieures normalisées des poignets suspendus.PRINCIPALES MESURES DE RÉSULTATS : Rupture des arcs I et II de Gilula et sensibilité du test d’étirementcarpien comparativement à d’autres examens.

Docket: 1-5526 Initial: JNCustomer: CJS Apr/98

REYNOLDS, JOHNSTON, FRIEDMAN

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120 JCC, Vol. 41, No 2, avril 1998


Despite the sophistication ofcurrent investigative tools,the diagnosis of carpal in-

stability may still consume consider-able time and resources. This is espe-cially true for patients who presentwith chronic wrist pain but do notdisplay any radiographic features ofinstability.The basis of this study was a 26-

year-old woman who had been inves-tigated for 2 years for chronic dis-abling wrist pain, which followed ahyperextension injury to her domi-nant left wrist resulting from a motorvehicle accident (patient no. 2, TableI). She had been unable to work as adaycare worker because of the pain inthe central wrist region.Extensive investigations were car-

ried out. She first presented to an or-thopedic surgeon approximately 2years after the original injury. Plainfilms showed a small bony spur on theproximal ulnar pole of the scaphoidbut no evidence of an instability pattern(Fig. 1). At arthroscopy, the scapholu-nate junction was found to be com-

pletely disrupted. A surprisingly largestep deformity was noted at this site.This prompted us to obtain an intra-operative posteroanterior radiographof the wrist, while her hand was stillsuspended from wire finger traps with4.5 kg traction at the elbow. The stepdeformity seen through the arthro-scope was substantiated radiographi-cally (Fig. 2).The object of this prospective ex-

perimental study was to answer thequestion: Could a similar step defor-mity be provoked by traction in theawake subject who, like the baselinecase, had no radiographic signs of in-stability but had a proven tear of thescapholunate or lunatotriquetral liga-ments? Were this so, traction mightprove to be a sensitive screening toolfor tears of the scapholunate or luna-totriquetral ligaments before the de-velopment of a radiographicallydemonstrable instability pattern.

PATIENTS AND METHOD

Patients who had experienced wrist

pain for more than 3 months andwhose clinical picture was suggestiveof carpal instability were investigatedwith plain radiographs, stress views,bone scintigraphy, radiocarpal arthro -graphy and arthroscopy. Only patientswho had intercarpal, proximal row,ligamentous tears at arthroscopy butwhose plain and stress views failed todemonstrate an instability patternwere included in the study.Gilula1 described 3 radiographically

derived arcs from the posteroanteriorwrist radiograph, the first of whichoutlined the proximal bony contour ofthe carpal bones of the proximal carpalrow. A broken arc was strongly sugges-tive of abnormality at the site of thebreak, be it from ligamentous disrup-tion, fracture or synovitis. Small inden-tation of the arcs at each joint shouldnot interfere with the main arc curva-tures. Uncommonly, very minimal off-sets in arcs I and II at the lunatotrique-tral joint may be normal, especially ifthe wrist is in extremes of radial or ul-nar deviation. Because the triquetrumvaries in shape, particularly along its

PRINCIPAUX RÉSULTATS : On a enregistré des déformations graduelles variant de 2,5 à 6 mm (moyenne de3,7 mm) dans les poignets atteints et de 0 à 4 mm (moyenne de 1,5 mm) dans les poignets «non atteints».Le test était plus sensible que l’arthrographie radiographique traditionnelle et la scintigraphie pour définir àla fois la présence et le site de déchirements ligamentaires aux pôles proximaux, et presque aussi sensibleque l’arthroscopie.CONCLUSION : Chez les patients qui souffrent de douleur chronique aux poignets et qui sont atteints d’in-stabilité dissociative dynamique du poignet, le test d’étirement carpien peut être un moyen utile dedépistage de déchirements ligamentaires aux pôles proximaux.

Table I

Negative

Negative

Negative

Negative

Positive

Negative

Bonescan

Data on 6 Patients Who Underwent the “Carpal Stretch Test”

Negative

Positive

Positive

Positive

Patientno.

Negative

Negative

Arthrogram

1

2

Lunatotriquetral

3

Lunatotriquetral

Lunatotriquetral

Scapholunate

Scapholunate

Scapholunate

Arthroscopy

4

3.5

3

2.5

6

3

Affectedwrist

Stretch test, mm

4*

1

0

0

3

1

Oppositewrist

M

F

F

Sex

29

26

27

Age,yr

Dominant

Dominant

Dominant

Wristdominance

4 M 25 Non-dominant

5 F 29 Dominant

6 F 20 Both

proximal surface, occasionally in thenormal wrist arc I may be lost at theulnar side of the lunatotriquetral joint.However, arc II will still be smooth,unless there is a tear locally.A radiographic protocol, the

“carpal stretch test,” was devised.Both the affected and unaffected con-trol wrists in the awake patient weresubjected to the same testing. No se-dation was necessary since the test waswell tolerated. With the subject supineand the shoulder abducted 90° andexternally rotated 90°, the arm wassuspended from an “intravenouspole” by wire finger traps attached tothe middle and ring fingers, with a 4.5kg weight over the flexed elbow. Thiswas maintained for 10 minutes, andthen a single posteroanterior (PA) x-ray view of the wrist was obtained. Po-sitioning of the x-ray tube was stan-dardized to 100 cm. A special splintheld both the hand and an x-ray cas-sette in the desired position. A 10° ul-nar wedge was attached to the surfaceof the splint. Two radiologists, bothmasked as to the affected and controlwrists, assessed the resulting radi-ographs. They were asked to identifyand measure, in millimeters, any step

deformity in Gilula’s arc I or II. Theradiographs were reread on a separateday, by the same 2 observers, and theresults were compared with their pre-vious recordings.Carpal stretch tests were performed

in 6 patients who satisfied these criteria.Sensitivities, defined as the propor-

tion (or percentage) of “diseased”subjects who had a positive test, werecalculated for bone scanning, arthrog-raphy and the stretch test in this selectpopulation in whom the “disease” wasknown to be present by arthroscopy.

RESULTS

Four of the 6 patients were women,and all 6 were in the third decade oflife. The duration of symptoms beforediagnosis ranged from 18 months to 4years. The dominant wrist was the in-jured wrist in 4 cases. One woman hadbilateral wrist pain.All patients underwent bone scan-

ning. Only 1 had increased uptake ofthe radioisotope (sensitivity: 17%).Single-injection radiocarpal arthrog-

raphy was performed in all patients.However, only 3 demonstrated leakageof dye into the midcarpal row, and in

none was the specific interosseous routefrom the proximal to midcarpal rowsshown conclusively (sensitivity: 50%).Because many patients demon-

strated step deformities during thecarpal stretch test in Gilula’s arc I at thelunatotriquetral junction, in bothwrists, we elected to measure the“step” at the lunatotriquetral joint inarc II only. Resulting step deformitiesof Gilula’s arc I, for scapholunate dis-ruptions, and arc II, for lunatotrique-tral tears, in the 6 patients’ affectedwrists ranged from 2.5 to 6 mm. In theoriginal patient, the step deformity seenintraoperatively was reproduced withthis “carpal stretch test” (Fig. 3). Thesmallest step at the scapholunate sitewas 2.5 mm in a patient who had an in-completely torn interosseous ligamentidentified at arthroscopy (Fig. 4). A lu-natotriquetral tear prompted a step of3.5 mm on average (Fig. 5) (sensitiv-ity: 83% for a step of 3 mm or greater).The unaffected wrist displayed 0 to

1 mm of “step” or displacement ofGilula’s arc in 4 of the 6 cases. Stepdeformities of 3 and 4 mm were seenin the other 2 wrists. The clinical andinvestigative findings are summarizedin Table I. Interobserver error was



CJS, Vol. 41, No. 2, April 1998 121


FIG. 1. A small bony spur (arrow) is noted on the proximal ulnar corner of the scaphoid in this 26-year-old woman (patient no. 2 in Table I) whose wrist had been injured in a motor vehicle accident 2years previously. The scapholunate cartilage distance is normal.

FIG. 2. Arthroscopy of the wrist (same patient asFig. 1) showed a large step from the lunate tothe scaphoid, and this was recorded radiograph-ically (arrow).



122 JCC, Vol. 41, No 2, avril 1998


zero. That is, the 2 radiologists didnot differ in either their reading of thepresence or the degree of a step defor-mity. Intraobserver error was also zeroin all cases except for 1 measurementthat differed 0.5 mm from the previ-ous measurement of the same case.

Both radiologists committed this samevariation for the same wrist.In the 6 patients with arthroscopi-

cally confirmed proximal row carpalligament disruption, there were seem-ingly 2 false-positive recordings (3 and4 mm in the opposite wrists). A


FIG. 3. Comparison of the “stretch” under general anesthesia (left, arrow) and under the experimen-tal conditions (right, arrows) demonstrates little difference in the step deformities (same patient asFig. 1). Gilula’s arcs I and II are superimposed, for reference.

FIG. 4. A 2.5-mm “stretch” (arrow) in a patientwith a partial tear of the scapholunate ligament(same patient as Fig. 1)

FIG. 5. A 3.5-mm “stretch” (arrow) in a patientwith a tear of the lunatotriquetral ligament (pa-tient no. 5 in Table I).



CJS, Vol. 41, No. 2, April 1998 123


scapholunate gap of 3 mm occurredin the asymptomatic wrist of onewoman, with a 6-mm step in the op-posite wrist at the same site (Fig. 6).In the second instance, a 20-year-oldstudent and volleyball player pre-sented with bilateral, but especiallydominant-sided, ulnar wrist pain.Both the arthroscopy and “stretchtest” were positive on the investigatedside for a lunatotriquetral ligamenttear. The opposite wrist has remainedsymptomatic but not to such a degreethat the patient would wish any fur-ther investigation. Clinically, a luna-totriquetral injury was suspected onthe unaffected side. The “stretch test”was positive (Fig. 7).

DISCUSSION

Post-traumatic scapholunate disso-ciation is the most common form ofcarpal instability. Subluxation of theproximal pole is possible when thetethering mechanisms of the volar as-pect of the proximal pole are disrupted(deep radioscapholunate, scapholunateinterosseous ligaments and scaphoidattachment of the volar radiocapitateligament).2–5 Sebald, Dobyns and Lin-scheid6 confirmed that classicroentgenographic changes of instabil-ity may not be present for weeks,months, and in some of the lesser in-juries, for years after disruption of ascapholunate ligamentous complex.This Mayo Clinic group also describedincomplete scapholunate instability,characterized by dorsal wrist pain andswelling, tenderness of the scapholu-nate articulation and decreased gripstrength. In these patients, no frankscapholunate diastasis or a carpal col-lapse pattern was evident on radi-ographs. The arthrogram, however,was positive.Vance, Gelberman and Braun7 sug-

gested that scapholunate dissociationmight occur in the absence of a his-

tory of trauma and that the dissocia-tion might be bilateral. Generalizedligamentous laxity may be such acausative factor.In our study group, only 1 subject

could remember a significant accidentthat might have been responsible forthe chronically painful wrist.Clues on the plain radiographs as to

the presence of underlying carpal insta-bility have included an increased scaphol-unate distance, or Terry Thomas sign,8,9

foreshortening of the scaphoid10,11 and acortical ring sign.12 A vertical scaphoid13

and a “V” sign14 on the lateral radi-ographs have been described. Abnormalintercarpal subtended angles or the pres-ence of intercalated segmental instability

FIG. 6. Same patient as in Fig. 1 demonstrated steps (arrows) of 6 mm on the left and 3 mm on theright (the injured and asymptomatic sides, respectively).

FIG. 7. Another patient (patient no. 6 in Table I) on “stretch” displayed bilateral lunatotriquetral arc IIdisplacement (arrows). The more symptomatic of the 2 sides is on the left. Note the different verticalheights of the lunate and the triquetrum, attributing to the marked disruption of arc I on the ulnarside of the wrist.



124 JCC, Vol. 41, No 2, avril 1998


are also well-established criteria for thediagnosis.13

In our study, bony irregularity ofthe scapholunate junction in 1 patient,manifesting itself as a small spur at theproximal pole of the scaphoid, mightalso provide a clue as to the presenceof underlying interosseous ligamentdisruption.If the interosseous distance and

scapholunate angles are normal onstandard radiographs, Dobyns and as-sociates15 have recommended the “mo-tion study,” which consists of 6 viewsof the wrist. Gilula and Weeks3 sug-gested a series of 10 radiographs, in-cluding the 6 views of Dobyns as wellas clenched-fist views. Moneim16 posi-tioned a 20°wedge block under the ul-nar border of the hand at the time ofposteroanterior radiography to maxi-mize the scapholunate interval.Thompson, Campbell and Arnold17

advocated the supination anteroposte-rior view, and Ruby and colleagues18

recommended a stress view with thewrist in slight flexion and ulnar devia-tion, to better demonstrate scapholu-nate dissociation. Additionally, appli-cation of compressive forces to thecarpus, such as by a clenched fist, maypotentiate instability to the point atwhich the radiographic features of in-stability can be identified.15,19

Only 1 of our patients had increaseduptake of the radioisotope on bonescanning, at the site of the abnormality— a scapholunate ligament tear. Subtleosteoarthritic changes were evident atthe scapholunate junction, likely con-tributing to the radiotracer uptake. Pinand colleagues20 showed that scinti-grams were abnormal in 95% of casesinvolving complete intrinsic ligamentruptures and fractures. However, theyfound that scintigraphic findings corre-lated poorly with partial intrinsic liga-ment ruptures and with cases of synovi-tis. We did not find radioisotope studiesto be useful as suggested.

No 3-compartment arthrographywas performed in our patients. Singleradiocarpal injection demonstratedleakage of dye into the midcarpal rowin only 3 of the 6 cases and it was non-specific as to the site of the ligamentdisruption.Arthroscopy, in experienced hands,

has become the standard against whichother methods of instability detectionmight be compared. The techniquehas been well described,21 and Northand Thomas22 have defined the arthro-scopic features of the volar wrist liga-ments. This technique is generally con-sidered to be superior to arthrographyin detecting disrupted ligaments, andindirectly, instability. However, this in-vasive means of detection, requiringanesthesia, instrumentation and expe-rience, should be reserved for thosewhose preliminary wrist investigationhas been fruitless but in whom theclinical suspicion of an underlying ligamentous tear remains.The role of traction is not new in

either the investigation or the treat-ment of carpal bone injuries. BothGreen and O’Brien23 and Dobyns andassociates15 have demonstrated thevalue of traction in fresh carpal frac-tures and fracture-dislocations.In this experimental study, in the af-

fected wrist group, the carpal stretchtest approached the sensitivity ofarthroscopy, in defining both the pres-ence and the site of an underlyingcarpal instability not identified by tra-ditional motion studies, scintigraphyand radiocarpal arthrography. On theaffected sides, a step deformity of 3mm or more appeared to be a reliableindicator of an intercarpal ligamentoustear. A step deformity of 0-1 mm wasthe rule in the unaffected wrists but forthe 2 exceptions. That these 2 wristsmight also have underlying instabilityor that there may be, as Vance, Gelber-man and Braun7 described, premorbid(and perhaps predisposing) ligamen-




CJS, Vol. 41, No. 2, April 1998 125


tous laxity, may be possible explana-tions for these unanticipated results.In our study, the steps in arc I at the

scapholunate junction were recordedusing the lunate for the Gilula referenceline, and measuring the vertical dis-tance to the intercept of the scaphoidarc. Measurements were reproduciblewith the use of this scheme. Steps in arcII, at the lunatotriquetral articulation,again used the lunate as the reference.The only caveat in the reading of thestep in this region was the influence ofthe hamate facet on arc II on the “uln-armost” border of the lunate. Thedrawing of arc II should not fall intothis hollow, or else false-positive valueswill be noted. This facet is easily identi-fied and easily ignored.Utilizing the fact that the ra-

dioscapholunate and interosseous liga-ments have been torn, and that the ulnocarpal complex has remained un-injured, one can imagine the effect onGilula’s arc I of traction on the destabi-lized scaphoid: it will follow the distalrow. Conversely, if the lunatotriquetralcomplex is disrupted and the ra-dioscapholunate complex uninjured,then one can again imagine the effecton Gilula’s arcs I and II of traction onthe destabilized triquetrum: it will fol-low the distal row. In essence, the radi-ographically unappreciated, althoughdisrupted, relationship between thescaphoid and the lunate, in radial-sidedinjuries, and the triquetrum and lunate,in ulnar-sided injuries, is unmasked bytraction. This phenomenon seems tooccur before attenuation of a sufficientnumber, or degree, of ligamentousstructures to allow radiographicallydemonstrable dynamic instability, andcertainly before radiographic featuresof instability become evident.

SUMMARY AND CONCLUSIONS

An experimental pilot protocol —the “carpal stretch test” — was de-

signed to assess the possible role oftraction as a diagnostic investigativetool in proximal carpal row instabili-ties, before the development of eitherdynamic or static instability patterns.Scapholunate disruption was appreci-ated by a step deformity of 3 mm ormore in Gilula’s arc I and lunatotri-quetral disruption by a step deformityof 3 mm or more in Gilula’s arc II.The carpal stretch test approached thesensitivity of arthroscopy and was con-siderably more sensitive than tradi-tional radiography, arthrography andscintigraphy in defining both presenceand site of proximal carpal row liga-mentous tears in this small populationof patients who did not demonstratesigns of typical static carpal instability.

References

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2. Taleisnik J. Post-traumatic carpal insta-bility. Clin Orthop 1980;149:73-82.

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4. Palmer A, Dobyns JH, Linscheid RL.Management of post-traumatic insta-bility of the wrist secondary to liga-ment rupture. J Hand Surg 1978;3:507-32.

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6. Sebald JR, Dobyns JH, Linscheid RL.The natural history of collapse defor-mities of the wrist. Clin Orthop 1974;104:140-8.

7. Vance RM, Gelberman RH, BraunRM. Chronic bilateral scapholunate dis-sociation without symptoms. J HandSurg 1979; 4:178-80.

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