Limited Finger Movement After an Injury

PATIENT PROFILE:

A 24-year-old man seeks medical attention 3 weeks after he injured his little finger playingfootball. He reports that the finger "came out of place" at the middle knuckle (proximal interphalangeal[PIP] joint); he quickly put the finger back into place himself, quit playing, andiced it. About 2 hours later, he was unable tomove the finger without significant pain, andthe following day, inability to move it interferedwith his performance of tasks that requiredfine manual dexterity. Since then, thepain has decreased, but the finger remainsswollen and he has not been able to fully extendit at the middle knuckle. In addition, thetip of the injured finger is hyperextended.

WHAT IS YOUR PRESUMPTIVE DIAGNOSISAT THIS POINT?

A.

Torn distal interphalangeal (DIP) deepflexor tendon ("jersey finger").

B.

Torn DIP extensor tendon ("drop finger").

C.

Torn PIP extensor tendon("boutonnire finger").

D.

Torn PIP collateral ligament.

THE CONSULTANT'S CHOICE

This patient most likely has a torn extensor mechanismin the PIP joint, or boutonnire finger (choice

C

).His description of the injury suggests that he dislocatedhis finger. Dislocations are most common at the PIPjoint and can lead to a tear in the extensor mechanismof this joint. Inability to extend his finger at the PIP jointalso indicates a tear of the PIP extensor mechanism.A torn DIP extensor (choice B) is a possibility,but dislocation is not the usual mechanism of this typeof injury. In addition, patients with a torn DIP extensorusually complain of inability to raise the tip of the finger,while this man reports hyperextension. A torn deepflexor of the DIP (jersey finger) reduces the ability toflex the DIP; he does not complain of this. Torn collateralligaments do not produce difficulties with extension;moreover, if they do result in a deformity, it will consistof a medial or lateral deviation at the joint.A physical examination reveals the following:

• The patient has no difficulty in flexing the DIP joint(Figure 1); this rules out a torn deep flexor of the DIP(jersey finger) (choice A).
• There is no weakness of the collateral ligaments(Figure 2); this rules out torn PIP collateral ligaments(choice D).
• The middle phalanx of the injured finger is in flexion,and the distal phalanx is hyperextended (Figure 3).
• In a test for extension at the PIP joint, the patient isunable to extend his finger (Figure 4).

The examination results clinch the diagnosis of tornPIP extensor tendons (boutonnire finger). This conditionis caused by either forced flexion of an extendedPIP joint or dislocation of the same joint. The dislocationis usually volar but may be dorsal.Immediately after injury, swellingand ecchymosis are evident over thePIP joint. The point of maximum tendernessis over the dorsal surface ofthe PIP joint. There may also be lateral,medial, or volar tenderness, butthe maximum tenderness is dorsal.The PIP joint is weak, or the patientis unable to extend it altogether. Thejoint can be passively extended butwill not stay in that position.In a boutonnire injury, theextensor mechanism tears and thehead of the proximal phalanx thenbuttonholes through the torn extensormechanism (

boutonnire

isFrench for "buttonhole"). As a result, the lateral bands of the extensorsare able to migrate downward(in a volar direction) and they beginto act as flexors

(Figure 5).

Thismigration does not happen acutely,and initially the lateral bands mayact as weak extensors. However, intime, the downward migration occurs.The lateral bands, acting asflexors, then pull the middle phalanxinto flexion; simultaneously, thedistal phalanx becomes hyperextended.Although this process mayoccur acutely, it usually takes severalweeks, as it did in this man.

WHAT WOULD YOU DO NOW?

A.

Order an MRI scan.

B.

Order a plain radiograph.

C.

Refer the patient for physical therapy.

D.

Refer him for surgery.

THE CONSULTANT'S CHOICE

In all dislocations, fracture and incomplete reductionshould be ruled out by a radiograph (choice B). Inthe case of boutonnire finger, the articular surfaces ofthe proximal and middle phalanges need to be properlyaligned after reduction; a radiograph can be used toassess the alignment. An MRI scan (choice A) wouldadd little additional information; thus, its cost is notjustified. Physical therapy (choice C) will be helpful inthe future but not at this time. Surgery (choice D) maybe needed, but a radiograph must be ordered first.
The film shows good alignment and no evidence offracture.

WHAT WOULD YOU DO NOW?

A.

Splint the PIP joint in flexion.

B.

Splint the PIP joint in extension.

C.

Refer the patient to a hand surgeon.

D.

Advise the patient that the time for effectiveintervention has unfortunately passed.

THE CONSULTANT'S CHOICE

It certainly is not too late for effective intervention(choice D). In fact, several options are available.Splinting the PIP joint in extension (choice

B

) ismost likely to be effective. Splinting in flexion (choiceA) will increase the deformity and will not provide thedesired result. Surgical correction (choice C) is notalways successful. It is reserved for symptomatic chronicdeformity that does not respond to nonoperativemeasures.Splinting should be tried no matter how long thedeformity has been present. It is important that thesplint keep the PIP joint in extension and not allow flexion.However, make sure the split does not limit movementof the metacarpophalangeal and DIP joints. Encouragepatients to do DIP joint flexion exercises whilea splint is in place to decrease residual stiffness.The patient's finger was splinted in full extensionfor 4 weeks, and he was instructed not to remove thesplint under any circumstances. For the following 4weeks, the splint was used 12 hours per day.After the splint is removed, his finger feels betterbut he is unable to flex it at the PIP joint.

WHAT WOULD YOU DO NOW?

A.

Refer the patient for surgery.

B.

Do nothing; the ability to flex his finger willreturn shortly.

C.

Order an MRI scan.

D.

Refer him for physical therapy.

THE CONSULTANT'S CHOICE

Physical therapy (choice

D

) is the best choice in thissetting. There is no need for surgery (choice A), and anMRI scan (choice C) does not add to his care. If nothingis done (choice B), his disability will not diminish.A 3-week, twice-weekly course of physical therapywas prescribed. During therapy, ultrasonography wasused to loosen the joint. Ultrasonography and stretchingexercises increased joint movement. In addition, the patientwas instructed to squeeze putty with his injuredhand to help accelerate the recovery process. Movementslowly returned to the joint.For the first 2 months after physical therapy wascompleted, he participated in football and weight liftingwith the joint protected. Eight months later, the joint remainsslightly swollen, but there is no pain or limitationof flexion or extension. The patient is able to participatefully in sports and other activities that require grasping,and he feels fully recovered.