Extensor tendon injuries in the hand and wrist M Al-Maiyah April 2007

Extensor tendon injuries in the Extensor tendon injuries in the hand and wristhand and wrist

M Al-Maiyah

April 2007

IntroductionIntroduction Extensor tendons can be injured by closed injury

involving traction force, or open penetrating, lacerating or crushing injury.

Tendons can be weakened by age, trauma (EPL rupture after distal radial fractures) or Diseases ( as rheumatoid arthritis)

The consequence s of a tendon injury may affect more than one joint, since the tendons in the system have to act across sequential joints which are inherently unstable without balanced controls.

Methods of evaluating results in Methods of evaluating results in extensor tendon injuries 1extensor tendon injuries 1

Total active motion (TAM) Extension lag (is most important parameter) Flexion loss Grip strength

– Newport et al (1990, 1992); 62% of patients achieved excellent to good results,but if ETI associated fracture or dislocation then only 45% achieved excellent to good results.


Distal injuries (zone I-IV) had less favourable results than proximal (zone V- VIII).

Loss of flexion is a significant complication of extensor tendon injuries.

Dynamic splint associated with better results, 98-100 % achieved excellent to good results in ETI without associated injuries.


postoperative early controlled mobilisation using Dynamic splint (3rd postoperative day – 5 weeks) is effective and reliable method of rehabilitation (Zone III- VIII), while zone I &II best treated with static means .

Dynamic splint for early motion of ETIDynamic splint for early motion of ETI

Zones of injuries

Zone Finger Thumb

I DIP joint IP joint

II Middle phalanx Proximal phalanx

III PIP joint MP joint

IV Proximal phalanx Metacarpal

V MP joint Carpo-metacarpal jt.

VI Metacarpal

VII Dorsal Retinaculum

VIII Distal forearm

IX Proximal forearm

Zones 1 injuries Zones 1 injuries 11

Mallet Finger: loss of continuity or stretching of the extensor tendon over DIP joint, with characteristic flexion deformity of terminal phalanx.

Usually closed, may be open injury.

It usually caused by forceful flexion of extended finger, which result to tendon rapture or avulsion of bony fragment.

In 42% of cases, resulted from trivial trauma.


Patient cannot actively extend the terminal segment, but full passive flexion usually present.

It may associated with hyper-extension of PIP (Swan neck deformity may develop).

Treatment of closed mallet finger with or without fracture is by splintage (dorsal lip fracture of < 1/3 of the articular surface).


Splintage for 6 weeks is treatment of choice for all patients, without regard for the date of injury.

80% of cases achieve excellent to good result.

Poor results were caused by poor patient cooperation or inadequate immobilisation.

Mallet finger due to laceration of extensor mechanism about DIP joint can be treated with splintage.


Fresh laceration over DIP joint with mallet deformity are repaired by a running suture of 4-0 /5-0 synthetic material, which reapproximate the skin and tendon simultaneously, the dressing and splint. Removal of sutures in 10-12 day and splint to continue for 6-7 weeks.


Mallet injuries associated with significant fragment, may be associated with volar subluxation of the distal phalanx.

Operative treatment has been recommended for fracture fragment > 1/3 of articular surface.

Zones II injuries Zones II injuries 11

(Middle Phalanx injury/ Thumb proximal phalanx)(Middle Phalanx injury/ Thumb proximal phalanx)

In this zone, tendon injuries usually caused by lacerating or crushing injuries

Usually leads to partial tendon injury.

If tendon lacerations <50%, are treated by skin wound care, followed by active motion in 7-10 days.

If tendon laceration <50%, are treated by a running suture near the edge of laceration, followed by Silf-verskiold type cross stitch proximal and distal to the initial running suture

Zones II injuries Zones II injuries 22

(Middle Phalanx injury/ Thumb proximal phalanx)(Middle Phalanx injury/ Thumb proximal phalanx)

Zones III injuries Zones III injuries 11

(Boutonniere lesion, PIP joint)(Boutonniere lesion, PIP joint)

Disruption of central slip of extensor tendon at the PIP joint with volar migration of lateral bands resulting in loss of extension of PIP joint and compensatory hyperextension at DIP joint.



Boutonniere lesion, may be caused by closed trauma, with forceful flexion of PIP joint.

Boutonniere deformity,usually develop s 10-21 days following the injury.

It might be missed initially.

Painful tender PIP joint following recent injury should arouse suspicious.



Carducci (1981) recommended two test useful for early diagnosis; – A 15-20o extension loss at PIP joint when wrist and

MP joint fully flexed.– Extravasation of radiopaque dye dorsal and distal to

PIP joint .– Weak extension of PIP joint against resistance is

another diagnostic test (Lovett).



– Decrease of DIP extension while holding PIP joint in full extension is another test (Boyes). Due to volar migration of the lateral bands.



Pseudo-Boutonniere deformity a condition of PIP joint flexion contracture with restricted flexion of DIP. It could be the result of PIP joint hyperextension injury involving palmar plate, the first Cruciate pulley and oblique ligament.

Pseudo-boutonniere must be distinguish from true boutonniere , because pathology and treatment are different.

Detailed history of injury and initial clinical finding is crucial.



Principle of treatment of Boutonniere dependent on restoration of normal tendon balance of the central slip and lateral bands.

Treatment of acute injury, before fixed contracture has occurred can be achieved by: splint or k-wire to fix PIP joint in full extension.

Splintage of PIP and active flexion of DIP are believed to draw lateral bands dorsally and to reduce separation the torn ends of central slip.



Operative option maybe required for closed boutonniere deformity:– When central slip avulsed with bony fragment and

is lying free over PIP joint– Long standing deformity in a young person.

Bony fragment either fixed or excised (depends on its size) and tendon reattached to Middle phalanx.

K-wire of PIP joint for 10 days , followed by splint.



Volar anterior dislocation of PIP joint usually result in central slip rapture, ligamentous injury and subsequent boutonnière deformity.

This injury must be recognised and repaired.

Surgical repair has satisfactory result, but Stiff PIP joint still potential complication.



A fresh laceration of extensor mechanism at PIP joint, results in drop finger at PIP joint then boutonniere deformity.

This injury is likely to enter the joint, so the first aim of treatment is to prevent infection .

This should be treated surgically with joint irrigation/ debridement + tendon repair + Antibiotics

More complicated cases, may need reconstruction

Zones IV injuries Zones IV injuries 11

(proximal Phalanx injury)(proximal Phalanx injury)

Injury at this level is similar to that of zone II.

Usually partial extensor mechanism injury due to lacerating trauma.

It may need surgical repair of tendonAt this level the core suture could be usedEarly motion is recommended ( EVANS)

Zones IV injuries Zones IV injuries (Thumb metacarpal)(Thumb metacarpal)

At this level both EPL & EPB should be repaired

Tendons of substantial size so core sutures + cross stitch could be used

Early postoperative motion also required.

Zones V injuries Zones V injuries 11

(Finger MP joint)(Finger MP joint)

Human bite wounds; A small penetrating wound over the MP joint may be

caused by striking someone in the mouth with clenched fist.

Many patients deny this, careful history must be taken. This is contaminated wound, potentially infected. Gram positive bacteria (mainly Staph.) +/- Gram –ve. X-ray is obtained (fracture, foreign body)



The wound must be extended to permit joint inspection and culture is taken.

The wound is debrided, irrigated and left openAntibiotics are started preoperatively.



In human bite, most of tendon injury are partial and need not repaired immediately.

Hand should be splinted with wrist 45o extension and MP 15o flexion.

Tendon repair might be done secondarily in 7-10 days. When infection under control and dynamic splinting is started.

At MP level tendon laceration is repaired with 4/0 non-absorbable core suture and cross-stitch.

Dynamic splinting postoperatively.

Sagittal band injuriesSagittal band injuries

If open, needs repair, then gentle exercises to star on 3rd postoperative day.

Acute closed injury may occur.

Leads to subluxation of the extensor tendon, some time painful.

Treated by splinting for 6 weeks.

Sagittal band injuries 2Sagittal band injuries 2

Traumatic or spontaneous dislocation seen later than 2 weeks are treated by re-centralisation of extensor mechanism on MP joint.

Finger, zone VI injuryFinger, zone VI injuryHas better outcome than distal injuries.

– Unlikely to have associated joint injury– Increased subcutaneous tissue lessens the

potential for adhesion.– Greater tendon excursion

Can be treated with core tendon repair and cross- stitch, followed by dynamic splinting.

Wrist injuries (Zone VII)Wrist injuries (Zone VII)

At this level ETI is associated with dorsal retinaculum injury.

Tendons ends may retract because the tendons have synovial sheath.

Good results associated with tendon and retinaculum repair followed with dynamic splinting.

Distal forearm injuries (zone VIII)Distal forearm injuries (zone VIII)Open or closed injury.

If the injury in the tendon, then it could be repaired satisfactorily, but the muscle component less likely to retain the suture.

Muscle injury best treated by muscle transfer or by side to side suture. Followed by static splinting with wrist 45o extension and MP 15o

flexion for 4 weeks

proximal forearm injuries(zone IX)proximal forearm injuries(zone IX) Penetrating wounds with knifes or piece of glass is

the usual mode of injury.

The size of skin wound may give little indication of magnitude of injury

Loss of function might be due to nerve or muscle injury.

The wound must be explored carefully to determine the exact etiology of loss.

proximal forearm injuries(zone IX)proximal forearm injuries(zone IX) Nerve injury might be difficult to recognised in

immediate post-injury period.

EMG would be useful in3-4 weeks time.

The decision to undertake secondary nerve repair or muscle transfer depends on surgeon's experience.

Postoperatively, the extremity splinted with elbow at 90o, wrist 45o extension and MP 15o flexion for 4 weeks

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Extensor tendon injuries in the hand and wrist M Al-Maiyah April 2007