By Sean DadswellSeptember 2010

ContentAimsRefresh anatomy BiomechanicsDiagnosisPathologyTesting Treatment

AimsTo refresh and improve knowledge of wrist

anatomy and biomechanics and improve knowledge of wrist testing and treatments

Anatomy

Anatomy

Palmar Aspect Dorsal Aspect

WristBiomechanics difficult to

discuss without knowledge of anatomy

3 Planes of movementAll interdependent Instability therefore simply

wrist dysfunction

Distal radius, Triangular Fibrocartilage Complex (TFCC), distal ulna form stable base

Distal carpal row (hamate, capitate,trapizium & trapizoid) Joined by strong interosseous ligs and move as one unit

Proximal row (scaphoid, lunate, triquetrum & pisiform) change position in response to lig attachments and adjacent bone movements

Proximal row has no muscle attachments and is therefore inherently unstable when lig disruption

(Campbell, 1999; Berger 1996)

Fundamentals for wrist stability

Forces through Wrist55% force

transmitted through Radioscaphoid Joint

35% through Radiolunate joint

10% through TFCCBiomechanics and

instability can alter this significantly

55% 35%

10%

StabilityWrist highly mobileDepends on short,

strong intrinsic interosseous ligs and longer extrinsic intercapsular ligs

Intrincis ligs have origin and insertion in same carpal row

Scapho-lunate lig (SLL) and Luno-triquetral lig (LTL) important in proximal row as prevent separation of bones whilst allowing force through wrist and adaptation of bone positions

Extrinsic Ligaments‘V’ shaped volar focusing on

lunate proximally with limbs attaching to ulna and radius and capitate distally attaching to rad and triq via scaphoid

Dorsal aspect also ‘V’ shaped centring on the triquetrum and contains radio-luno-triq segment and trapezium, trapezoid, scaph segments

Other stability offered from flexor and extensor retinaculae and wrist flexors and extensors but these are not sufficient to prevent instability without ligs

Palmar

Dorsum

MovementsDistal row one unit

moves proximally when wrist is loaded

Compresses proximal row which flexes scaophoid 2ndry to palmar extrinsics

SLL then causes lunate flexion as well as capitate pushing into flex

Triquetrum then has flex force from LTL and ext force from distal row attachments. Flex force greater Therefore Triq flexes

Movement cont.Proximal row moves into

flex when distal row ext unless SLL insufficiency then the lunate will follow triquetrum into extension and scaphoid flexes excessively

Conversely if LTL insufficient then lunate follows scahphoid into flex and triq extends

During wrist flex and ext proximal row follows distal row

Ulna deviation (UD):Head of capitate

translates dorsallyExtends lunate (and

therefore scaph)Further UD causes

contact between hamate and triq which slides up and extends => further lunate ext. (palpable during movement)

Radial Deviation (RD):Trapizoid and trapizium

approximate to the radius and push scaph into flexion => lunate flex

InstabilityResults from

insufficiency of soft tissue restraints leading to abnormal movements

Different classifications

VISI or DISIVolar or Dorsal

intercalated segment instability

Relative lunate position to scaphoid

Intercalated ref to capitate and lunate connecting proximal and distal carpal rows

Scaphoid

Lunate

Instability cont. Numerous classifications and

terminology Popular one:

Carpal Instability Dissociative (CID): refers to instability between bones in same row

Carpal Instability Non-dissociative: instability between bones in separate carpal rows

Carpal Instability Complex (CIC): combination of CID and CIND (useful to describe elements of CID and CIND as guides treatment

Carpal Instability Adaptive (CIA): instability 2ndry to adaptation to abnormal bony architecture (eg malunion scap/rad etc)

DiagnosisHistory of trauma not always but most often presentFailed resolution of wrist sprainMechanism of injury (MOI)

Angle of impact (FOOSH or fall backwards)

Force (MPH, Height) Throwing injury

Detailed swelling, location of pain (radial, ulna, global or central and dorsal or volar), loss of function, treatments

Grip strengthPresence of click or snapping with or without painPrevious wrist injury’s or fracturesParesthesiaXrayArthroscopy gold standard

X Ray findingsTerry Thomas sign

Positive Terry Thomas sign indicative scapholunate instability

X Ray findings cont

Ring sign

Positive ring sign indicates scaphoid flexion (left) Normal (right)

X Ray findings cont

Ulnar variance

Positive ulnar varience (middle) and negative ulnar variance (right)

In ulnar neutral wrist 18% load goes through ulnar side of wristIf unlar length increased by 2.5mm force increases to 42%If ulnar length reduced by 2.5mm force reducs to 4.3% (Sachar, 2008)

X Ray findings cont

Gilula’s arc

Disruption of the first arc indicates luno triquetral instability via fracture or ligamentous instability

X Ray findings cont

Disruption of the second arc indicates scapholunate and lunotriqutral instability. Even though there is a gap in the first arc it can still be trace as a smooth arc

X Ray findings cont

Disruption of the third arc indicates capitohamate joint

Xray findings cont

Keinbock’s disease

Kienbock’s disease caused by AVN of the Lunate

PathologyCauses of wrist pain:

OA (1st cmc, piso-triq)RA#’sTFCC injuryCarpal tunnel syndrome Ulnar nerve entrapmentANV scaphoid/LunateECU subluxationNerve rootPronator teres trigger

points

DRUJ disruptionUlnar impactionCRPSDeQuervain’s

TestingWatson’s Scaphoid Shift TestTo identify scapho-lunate instability (scapho-lunate

ligament laxity/rupture)69% sensitive* 66% specific** (La Stayo and

Howell 1995)As almost 1/3 false negatives and 1/3 false

positives not very accurate but no further studies done to validate (Marx et al, 1999)

Needs to consider general hypermobility as more false positives in lax controls (Goldberg, 2006)

*Sensitivity indicated tests ability to predict presence of pathology

**Specificity indicates tests ability to predict true negatives/absence of pathology

Scaphoid shift test cont.

Sitting in an arm wrestling position. Examiner starts with the patients wrist in ulnar deviation and slight ext the applying pressure to the distal pole of the scaphoid to prevent palmar translation. Wrist is then radially deviated and slightly flexed. Pressure is then released.

If positive the scaphoid subluxes over the distal rim of the radius and there will be a click/clunk when pressure is released

In normal wrists the examiner will feel the scaphoidflex forward as the wrist is deviated radially

The Watson's test.

Luno-triquetral Ballotment Test (Regan’s Test)Identifies laxity of luno-triquetral ligSensitivity 64% Specificity 44% (therefore can

be false positive in > 50% of normals) (La Stayo and Howell 1995)

Better at predicting the absence of pathology rather than the presence of it (Marx et al 1999)

Poor validity from research but few attempts to validate

Ballotment testing of carpal mobility showed good inter and intra tester reliability therefore useful is wrist assessment (Staes et al 2009)

Regan’s Test cont

Simple PA of triquetrum on fixed Lunate

MUST BE COMPARED LEFT TO RIGHT

Positive if crepitus, pain of laxity felt compared to opposite side

The posterior side of the triquetrum is easily found as one can palpate the insertional crest of the posterior radiotriquetral ligament. Just distal to the crest lies the triquetrohamate space

The lunotriquetral ballottement test (Reagan's test)

Dorsal Wrist SyndromeGoldberg et al 2006Palpation base 3rd

MC and drop off capitate into fossa over scaphoid

Indicated scaph OA or scapholunate injury/instability

No spec or sens

Pivot Shift Test for Mid-carpal JointTest for ant capsule

and interosseous lig injury leading to capitate instability (Tuiana et al 1998; McGee, 1997)

Described in textbooks only there no spec or sens

Mid carpal joints most likely falling onto flexed wrist

Dorsal to volar pressure applied to capitate with hand in full supination then moved from radial to ulnar to radial deviation

Pain or ‘clunk’ indicates positive test

Anterior Draw Reddy and Compson

(2005) discuss lack of specificity in terms of individual structure

May indicate CICAnterior Draw test

Piano Key TestTest for Distal

radioulnar joint (DRUJ) instability

No spec or sensAlthough Moriya

(2009) found it to be valid in cadarvic study

Disruption of dorsal or palmar radioulnar lig

Positive with more than 5mm difference in movement compared to asymptomatic side

Piano Key Test

DRUJ Compression Test

Compressive force applied to DRUJ in 15-30 degrees supination

Wrist then pro and supinated

Positive with reproduction of pt’s symptoms

Indicates DRUJ OATextbook description

only

Shear Test for TFCC

Reddy and Compson (2005) Mini-symposium describse test but no Spec or Sens although construct validity OK

Indicated TFCC degeneration or injury

DRUJ held by examiner then axial load applied with Unlar deviation followed by passive pro and supination

Positive test click or painSachar (2005) discusses pronation leading to ulnar abutment as increases positive ulnar variance

•TFCC most common source of ulnar sided wrist pain and are either traumatic of degenerative•Occur with falls onto ulnarly deviated extended wrist or at extreme rotation•Often related to +ve ulnar variance (Osteotomy required)

Palpation TFCCSachar (2008) found

Specificity 87% Sensitvity 95%

Indicative of ulnotriquetral lig injury or TFCC injury/degeneration

Ulnomeniscotriquetral Dorsal Glide(UMTDG)Indicateds TFCC

injury66% sensitive64% specificIdentified in study

tested against arthroscopy (La Stayo and Howell, 1995)

May be beneficial to use multiple tests

Radius stabilised by examiner then using pinching motion between thumb and index finger of the opposite hand the piso-triquetral complex is moved dorsally whist the ulnar is squeezed palmarly

Piso-Triquetral Grind TestIndicates Piso-triquetral

OA most frequently but also pisiform instability

Need to differentiate between piso-triq OA and FCU tendon problem. (Palmar, 1995) advises palp FCU whilst resisting wrist flex and unlar deviation for FCU testing

Nakamura (2001) describes principle as accurate but offers no spec or sens

Piso-trquetral grind test:Examiner grips pisiform between thumb and index and rotates whilst compressing joint.Positive result is pain

Finklestein’s TestIndicates De Quervain’s

(Stenosing tendovaginitis /synovitis of 1st extensor compartment )

Batteson et al (2008) reports upto 100% sens and spec when used as part of a De Quervain’s screening tool but otherwise no reports of Sens or Spec

Screening tool included pain, tenderness, thickened APL or EPB, swelling,pain on resisted thumb ext

Finklesein’s test: Positive if pain illicited

CMC Grind TestIndicates 1st CMC

joint OANo spec or sens

availableNeed to differentiate

from De Quervain’s Examiner axially

compresses 1st CMC joint then med and lat rot 1st MC

Positive with pain or crepitus illicited

Carpal Tunnel syndromeMost common nerve entrapment

with prevalence upto 6%Compression of median nerve

beneath the transverse carpal LigPredominantly sensory S&S with

nocturnal S&S a classic feature.Nerve conduction studies often

used even when clinical picture clear to confirm CTS diagnosis (not efficient/cost effective

Using multiple tests can increase accuracy of clinical tests(Boland and Kiernan, 2008)

Phalen’s TestSensitivity 64-75%Specificity 75-94%(Boland and

Kiernan, 2008; Tetro et al, 1998)

Both studies reportPositive test

reproduction of pt S&S Phalan’ s test position held for

60 seconds

Tinel’s TestSensitivity 74%Specificity 91%Direct tapping over

transverse carpal lig with finger or reflex hammer

No conscensous on number of taps

Positive with reproduction of S&S

Tinel’s test

Carpal Compression TestSensitivity 75-90%Specificity 90-93%Direct pressure over

transverse lig for 30 seconds

Spec and Sens may be improved by adding flexion to wrist (up to 99% but evaluating own test) (Tetro et al, 1998)

Ulnar Nerve Entrapment Guyon's canal syndrome

is an entrapment of the ulnar nerve as it passes through a tunnel in the wrist called Guyon's canal.

Common in cyclists and RSI of ulnar border of hand on desk

Tested by compressing over Guyon’s canal

Nerve conduction studies

Differentiate higher ulnar nerve entrapment

Treatment for Instability

Incomplete lig tears can be splinted for 6-8/52

Goldberg (2006) reported 500 hand surgeons agreed acute or chronic wrist instability should be treated surgically

Main surgery are:Lig repairsWith or without K WireWith or Without

Capsulodesis

Carlsen and Shin (2008) recommend stages to repairs depend on soft tissue quality:Lig repairs/Anatomical

reconstruction for acute injury with good soft tissue

Salvage* ops where tissue is poor

Salvages ops where significant OA or non reducable deformity exsists

*Salvage ops ref to intercarpal arthrodesis, total wrist arthrodesis

(Minimal RCT evidence for concervative treatments)

Other Surgical Options (not specific to instability)

Ulnar osteotomy: can tighten TFCC complex or reduce positive ulnar variance

Pisiformectomy: for OA

CTS releaseScaphoid ORIF:

necessary in unstable prox pole #’s as 55-95% => AVN

If non-union occurs further options are:Radial styloidectomyExcision of the

proximal fragmentProximal row

carpalectomyBone graftTotal or partial

arthrodesisVascular bone graft (to

revascularise scaphoid)

Conservative treamentsCTS

Splinting (night)Oral steroidsWrist mobsInjections

All offer good short term outcomes

(O’conner et al, 2003; Marshall et al, 2007)

Surgery better than splinting (Verdugo et al, 2008)

TFCC injuriesAvoid aggsRestSplintingInjectionArthroscopic

debridment (66-87% success increased to 87-99% with ulnar osteotomy)

Conservative treatments cont.

De Quervain’s: No evidence for splinting rather than injection (Coldham, 2008)

Treatments to increase ROM: HEP better than mob’s but mob’s are helpful (Michovitz et al 2004; Krischak et al 2009)