Finger Sprains and Deformities

Gary Solomon

Digital injuries and deformities are common reasons why patients are referred to therapy for treatment. Many patients expect digital injuries to heal on their own, and sometimes do not recognize that the injury can lead to permanent deformity.

Patients may be referred to therapy with the diagnosis of “sprain / strain” for a finger or thumb but may actually have unidentified serious injuries, such as gamekeeper’s thumb or a volar plate (VP) injury. This may be especially likely when the referral comes from a physician who is not a hand surgeon. In this situation, the therapist has an opportunity to identify the clinical findings and facilitate appropriate treatment.

Injuries to the digits occur often in sports. Football players have a high incidence of proximal interphalangeal (PIP) joint injuries. In these sports-related injuries, dorsal dislocations are more common than volar dislocations. Boutonniere deformities frequently occur in basketball players. Mallet injuries occur when the player’s fingertip strikes a helmet or ball.¹ Therapists whose clients participate in sports can expect to see these common sprains and finger injuries as part of their caseload.

Many non-athletes enjoy sports activities after work, and these “weekend warriors” often sustain finger injuries that initially go untreated. Clients who later seek medical attention may have chronic pain, edema, and stiffness. More long-term problems, such as persistent residual pain and swelling, can be very challenging to treat.

Mallet fingers, boutonniere deformities, and swan neck deformities are common finger injuries that can be recognized by a hand therapist. They can be treated successfully by precise management. The trauma and disease processes that cause these deformities vary, but regardless of the cause, the therapist’s detailed knowledge of pathomechanics and therapy guidelines helps to manage and direct the course of treatment.

Mallet Finger

A finger with drooping of the distal interphalangeal (DIP) joint is called a mallet finger (Fig. 29-1).² Typically the DIP can be passively corrected to neutral, but the client is unable to actively extend it; this condition is called a DIP extensor lag. If the DIP joint cannot be passively extended to neutral, the condition is called a DIP flexion contracture. A DIP flexion contracture seldom is present early after injury; however, if the injury goes untreated, this problem may develop.

Anatomy

The DIP joint of the finger is a ginglymus joint, or hinge joint. It is bicondylar (it has two condyles) and is similar to the PIP joint in its capsular ligaments. The terminal extensor tendon and terminal flexor tendon attach to the most proximal edge of the distal phalanx. This insertion contributes to the joint’s dynamic stability.³

Diagnosis and Pathology

A mallet injury frequently is caused by a blow to the fingertip with flexion force or by axial loading while the DIP is extended.⁴ The terminal tendon is avulsed. An avulsion fracture also may occur and should be ruled out. Laceration injuries (extensor zone I) are another cause of this deformity. Anterior/posterior (A/P) and true lateral x-rays typically are obtained. In addition, the PIP joint should be examined for possible injury.⁵

Timelines and Healing

The DIP joint is immobilized by an orthosis in full extension for approximately 6 weeks to allow the delicate terminal tendon to heal. The joint should not be allowed to flex even briefly during this period of immobilization. After 6 weeks, the client is weaned off the orthosis while the therapist observes for DIP extensor lag.

Non-Operative Treatment

An orthosis is fabricated to hold the DIP joint in extension to slight hyperextension, depending on the physician’s preference. If hyperextension is recommended, the therapist should make sure the position of hyperextension is less than that which causes skin blanching. Exceeding tissue tolerance in DIP hyperextension can compromise circulation and nutrition to the healing tissues.⁶

Many types of DIP orthosis designs are available, and clients sometimes need more than one type (Fig. 29-2). They may also need an orthosis designated for showering; the client can carefully remove it after showering, according to the therapist’s instructions, and replace it with a dry orthosis. In this way, the skin is protected against maceration, which occurs if a wet splint is left on a digit. Casting also can be used when client compliance is a concern.

FIGURE 29-2 Mallet orthoses.
A, Custom thermoplastic volar. B, Dorsal. C, Combination dorsal/volar. (Reproduced with permission, Gary Solomon, MS, OTR/L, CHT.)

Perforated material is recommended to allow airflow. The PIP should be allowed to fully flex without disturbing the position of DIP extension. If multiple orthoses are provided, consider one dorsal and one volar so that the patient may switch to protect skin integrity.

If the DIP joint cannot be passively extended to neutral, serial adjustments of the orthosis may be done. If necessary, a small static progressive DIP extension orthosis can be used.⁷ Edema is treated as appropriate, and normal PIP active range of motion (AROM) with the DIP immobilized is promoted. Dorsal edema and tenderness over the DIP are common and can interfere with full DIP extension.

After 6 weeks of continuous orthosis use, if no DIP extensor lag is present and the physician approves, gentle AROM can be started. A template may be provided (Fig. 29-3) to allow the patient to actively flex and extend the DIP joint from 0° to 25° for 1 week, and then adjusted to allow 35° of flexion the next week. If no lag is present, gentle composite AROM should then be permitted. The therapist should instruct the client to avoid forceful or quick grasping or forceful DIP flexion in the early phase of AROM therapy, and emphasis during exercise should be on DIP extension. It is very important to watch for DIP extensor lag. If DIP extensor lag occurs, the orthosis use and exercise progression must be adjusted. Passive motion to restore DIP flexion should not be used except in cases of extreme stiffness with limited progress with AROM only. Passive flexion will significantly increase the risk of extensor lag especially early in the rehabilitation process.

FIGURE 29-3 Exercise template for initial protected AROM. (Reproduced with permission, Gary Solomon, MS, OTR/L, CHT.)

The use of the DIP extension orthosis is typically continued between gentle AROM sessions initially, and then gradually weaned over a 2 to 3 week period. Night orthosis use typically continues for an additional 2 to 3 weeks. If DIP extensor lag recurs, daytime use should be reinstituted. If orthosis use does not correct the DIP extensor lag, surgery may be needed to correct the problem.

If there is a mild extensor lag, the therapist should monitor closely for the development of a secondary swan neck deformity. If PIP hyperextension is noted, then an orthosis that blocks end range PIP extension while allowing full flexion is recommended.

Although the use of an orthosis is best initiated as soon as possible after injury, even a delayed regimen can be effective.⁸ Operative intervention can produce complications; therefore, non-operative solutions often are well worth the effort.

Operative Treatment

If the mallet injury has associated large fracture fragments (greater than 30% of the joint surface) or the patient asserts that they cannot be compliant with orthosis use, surgery may be necessary. A variety of procedures can be performed to treat this injury.4,9,10 Surgical complications include the possibility of infection and nail deformities.

The client may be sent to therapy with the DIP pinned for edema control as needed, instruction in pin site care if the Kirschner wire protrudes through the skin, and a protective orthosis . When the pins are removed, AROM is initiated. The DIP extension orthosis is continued when the pins are removed and then use is gradually weaned. As with non-operative treatment, the therapist should observe for DIP extensor lag.

Questions to Discuss with the Physician

• Is there a fracture (bony mallet)?

• Are you anticipating approximately 6 weeks continuous immobilization?

• Does the physician prefer the DIP in neutral position or in hyperextension?

• If the DIP is pinned, how long will the pin remain in place?

• Will an orthosis be needed after pin removal?

What to Say to Clients

About the Injury

“Here is a diagram of the anatomy of the distal digit and the terminal tendon. The terminal tendon is very delicate, and in order to heal, it needs continuous, uninterrupted DIP support for about 6 weeks.” Reiterate this concept as necessary until the client appears to understand the importance of continuous DIP extension.

About the Orthosis

“It is important for us to practice techniques for putting the orthosis on and taking it off while maintaining DIP extension. One technique is to keep the hand palm down on the table and carefully slide the orthosis forward. A second technique is to use your thumb to provide support under the fingertip while using your other hand to remove the orthosis, sliding it forward. To reapply, maintain DIP extension with your other hand as you put the orthosis back on.”

Work with the client to devise a schedule for removing the orthosis one or two times daily to clean the orthosis and check the skin. Make sure the client knows the proper techniques for keeping the DIP always supported in extension.

Emphasize the importance of skin care: “Moisture that is trapped inside may lead to skin problems such as maceration, which must be avoided.” Teach the client what skin maceration looks like.

About Exercise

“Initially, I am going to have you remove the orthosis four to six times a day and gently bend the tip down to the template. In 1 week, I will increase the amount of bending permitted, and the following week, you will begin making a full fist.”

“Avoiding resistive or powerful gripping or forceful bending or flexion of the injured fingers and of the entire hand is important to prevent any strain on the healing terminal tendon.”

Instruct the client in AROM for the uninvolved digits and especially PIP flexion of the injured digit: “Achieving full PIP active flexion is very important. The injured finger could stiffen at the PIP if it is not exercised gently. It is very important to prevent the uninjured digits from stiffening.” Demonstrate and practice gentle PIP blocking exercises, isolated flexor digitorum superficialis (FDS) and “straight ist” motions with the DIP orthosis in place (Fig. 29-4).

Evaluation Tips

• The client’s finger is likely to be tender and swollen over the dorsal DIP area. Use a gentle touch around this area.

• Circumferential measurements may be best deferred to avoid causing pain by applying or cinching a tape measure or similar measurement device. Also, measuring the DIP joint is difficult while maintaining and supporting the digit in full DIP extension.

• Assess the client for digital hypermobility. Observe for DIP extensor lag or PIP hyperextension of other digits and treat accordingly (see description of swan neck deformity).

• Check isolated DIP flexion of other digits gently while the injured DIP is immobilized if the client can isolate this without stressing the terminal tendon of the injured digit. This helps prevent the development of a quadriga effect.

Precaution. Avoid volumetric measurement, because this would leave the DIP unsupported, which is contraindicated.

Diagnosis-Specific Information that Affects Clinical Reasoning

Individualize the treatment based on your observation and evaluation. If DIP hyperextension has been ordered but the client cannot tolerate it, support the DIP in a tolerable position, and see the client every few days for splint modification until the desired position is achieved. Notify the physician if full DIP extension or hyperextension cannot be achieved in the orthosis.

If edema is significant, assume that you will need to re-adjust the orthosis as edema resolves, and schedule recheck visits accordingly. Upgrade the interventions as appropriate for edema management.

A client who is hypermobile and has laxity of the uninjured digits is at greater risk of developing a secondary swan neck deformity. This client needs an orthosis that prevents PIP hyperextension and supports the DIP in extension. Teach clients the isolated FDS exercise with the DIP orthosis in place.

Make sure your client is well trained in monitoring skin tolerances to the orthosis. Using more than one style of orthosis can help prevent skin problems.

Precaution. Clients should call for a recheck if any skin problems occur.

Tips from the Field

Orthoses

• Show the client pictures or samples of DIP orthoses. Explain your recommendation in terms of comfort, effectiveness, and adjustability. Ask clients about their preferences. Advise the client to tape (or use Coban) the orthosis in place at night to decrease the risk of the orthosis sliding off during sleep.

• Ask the client about their daily activities. If they perform a lot of fine motor tasks, consider a dorsal mallet orthosis.

• While fabricating the orthosis, keeping the PIP joint in flexion decreases the flexion tension on the FDP and makes it easier to fully extend the DIP joint.

• For a volar orthosis, it is critical that the lateral and medial borders are not greater than half of the width of the digit in order for the straps to contour and hold securely.

• Use a softer strap directly over the DIP joint where the skin is typically sensitive.

• Small orthoses are not always the quickest to make. Allow time to fine-tune the splint and re-adjust it as needed.

• Clients often appreciate having a separate orthosis to use in the shower. Also, they can change into the dry orthosis after the shower, which helps prevent maceration.

• When beginning active flexion of the DIP, trace the DIP in full extension from a lateral view onto a business card. This allows the patient to self-monitor for any developing extensor lag between therapy sessions (Fig. 29-5).

Exercise Template

Alumifoam makes an excellent template to use as a guide when patients begin active DIP flexion. The alumifoam template is also easy to adjust on subsequent visits as increased flexion is permitted.

Client Compliance

Some clients need more supervision and follow-up than others. Reasons to recheck the client more often include 1) resolving or fluctuating edema, 2) wound care, 3) PIP stiffness, 4) risk of swan neck deformity developing, and 5) questionable technique for putting on and taking off the orthosis. The therapy note should document whether the client demonstrates good technique in therapy and at follow-up.

Precautions and Concerns

• Check for skin maceration.

• Emphasize the importance of avoiding forceful or resistive gripping or quick flexion motions.

• Monitor for the development of PIP hyperextension, especially if the client demonstrates laxity of the digits.

• If the orthosis is taped on at night, caution the client to avoid circumferential taping, because this could produce a tourniquet effect.

Boutonniere Deformity

Anatomy

With a boutonniere deformity, the finger postures in PIP flexion and DIP hyperextension (Fig. 29-6). The injury may be open or closed. With a closed injury, the boutonniere deformity may not develop immediately but may become noticeable within 2 or 3 weeks after the injury.⁸ The client may have a PIP extensor lag or, with an older injury, a PIP flexion contracture. This distinction affects the therapy choices.

FIGURE 29-6 Boutonniere deformity. (From Burke SL: *Hand and upper extremity rehabilitation: a practical guide,* ed 3, St Louis, 2005, Churchill Livingstone.)

Diagnosis and Pathology

A boutonniere deformity involves disruption of the central slip of the extensor tendon, which normally inserts into the dorsal base of the middle phalanx. The disruption of the central slip causes the lateral bands to slip volar to the PIP joint axis of motion, creating flexor forces on the PIP joint.¹¹ The imbalance results in hyperextension of the DIP joint.¹² With this DIP posture, the oblique retinacular ligament (ORL) of Landsmeer, which is located at the dorsal DIP joint, is at risk of becoming tight. A pseudoboutonniere deformity is actually an injury to the PIP VP and is usually the result of a PIP hyperextension injury.

Clinical Pearl

With a pseudoboutonniere deformity, the damage occurs at the volar surface. With a boutonniere deformity, the damage occurs at the dorsal surface.¹

Timelines and Healing

A PIP extension thermoplastic orthosis or circumferential cast ¹³ is typically used day and night for up to 6 weeks (Fig. 29-7). When ROM of the PIP is initiated, flexion to 30° to 45° is typically permitted and advanced 15° per week as long as no lag is present (Fig. 29-8). This is followed by 3 weeks of nighttime and intermittent daytime orthosis use. The orthosis is used during the time needed for the central slip to re-establish tissue continuity and for correction of the deformity.⁸

FIGURE 29-7 A, Circumferential boutonnierre orthosis. B, Circumferential cast for boutonniere deformity. (Reproduced with permission, Gary Solomon, MS, OTR/L, CHT.)

A variation from complete immobilization for 6 weeks is a short arc motion ⁶ protocol that combines immobilization with intermittent controlled PIP motion to 30° to 40° of flexion during therapy sessions. After 3 weeks, the patient is provided a template for PIP ROM at home, and the template is advanced 10° to 15° per week if no lag is present.

Non-Operative Treatment

The ability to passively extend the PIP is a common indicator for non-operative treatment with PIP immobilization in extension. The MP and DIP are not included in the orthosis. Serial adjustments may have to be made to achieve full passive PIP extension. Different types of orthoses can be used for this purpose.

While the PIP is immobilized, it is very important that the therapist instruct the client in isolated DIP flexion exercises to recover normal length of the ORL. These exercises are done actively and passively in a gentle fashion (Fig. 29-9). The therapist should watch for normal MP AROM and should exercise this as needed.

FIGURE 29-9 Oblique retinacular ligament (ORL) stretch entails isolated DIP flexion with PIP supported in extension. This is done actively and passively. (From Clark GL: *Hand rehabilitation: a practical guide,* ed 2, New York, 1998, Churchill Livingstone.)

Precaution. After the client has been medically cleared to begin PIP active flexion, initiate restricted amounts of flexion at first and watch for PIP extensor lag.

It is important to emphasize PIP active extension, which is facilitated by positioning the digit in MP flexion. Continuous orthosis use is reinstituted as needed if a PIP extensor lag develops.

If exercise fails to recover DIP flexion with the PIP extended, ORL tightness (limited passive DIP flexion with the PIP extended) may need to be addressed with an orthosis. Various small, custom-made orthoses can be used for dynamic or static progressive DIP flexion with the PIP in full extension.¹⁴

Operative Treatment

Boutonniere deformity is caused by injury to zone III of the extensor tendons. Various surgical techniques are used to treat these injuries.⁸ The therapy protocol is determined in collaboration with the hand surgeon. The short arc of motion protocol for zone III extensor tendon repairs is appropriate if the client is considered a good candidate for this treatment (see Chapter 31).

Questions to Discuss with the Doctor

Non-Operative Clients

• Is the patient a candidate for early controlled active motion, or would continuous immobilization be preferred?

• Six weeks of immobilization is typical, is that when active PIP flexion should be started?

Operative Clients

• Was a strong repair achieved? (Ask to see the operative report.)

• Would this particular patient benefit from an early active motion protocol or more conservative therapy, such as immobilization?

• Are there any additional precautions?

What to Say to Clients

About the Injury

“Here is a diagram of the area of your finger that is injured. Notice how, as a result of injury to the central slip, the lateral bands have slipped forward (volar) and how they now contribute to the bent posture of the PIP joint. The PIP joint needs to be supported in extension for the injured tendon to heal in proper alignment. Also note how the end of the finger is tipped upward (hyperextended). As the injury at the PIP is corrected, the position at tip of the finger will also improve. In addition, specific exercises can help correct this.”

About Exercises

“With this diagnosis, improving DIP flexion while the PIP is extended actually helps improve PIP extension. Therefore, flexing just the DIP helps correct the lack of extension at the PIP. It is very important to exercise by bending the tip gently while the PIP is immobilized because this is corrective for your injury.”

Evaluation Tips

• Check for hypermobility of the other digits. Do the uninjured digits have a boutonniere-like posture?

• Determine whether the PIP joint can be passively corrected to neutral and whether the DIP joint can be passively corrected to normal flexion with the PIP in extension (that is., check for ORL tightness).

• Check and practice isolated DIP flexion of the other digits. Think ahead about preventing a quadriga effect.

• Check composite flexion of the other digits as you are able.

Diagnosis-Specific Information that Affects Clinical Reasoning

In nonoperative clients, determine whether the injury involves a PIP extensor lag (the PIP can be passively extended to neutral position, but the client cannot actively extend it) or a PIP flexion contracture (the PIP cannot be passively extended to neutral position). This distinction affects orthosis decisions (see later).

Determine whether the client has ORL tightness. With this condition, both active and passive DIP flexion with PIP extension are limited.

Tips from the Field

Clinical Picture

• Edema over the area of injury (dorsal PIP) worsens the deforming forces of a boutonniere position. Treat the edema as a high priority, because this helps recover PIP joint passive extension and promotes normalization throughout. Light compression wrapping can help reduce the edema.

• Isolating and exercising DIP active flexion of the uninjured digits while protecting the injured finger is a good measure for preventing a quadriga effect.

• PIP cylindrical thermoplastic or plaster orthoses may be helpful for performing isolated blocking exercises for DIP flexion. These can be used on all digits to isolate DIP active flexion with varying MP positions.

Orthosis

• If the client has a PIP flexion contracture, a corrective serial cast or orthosis is necessary. Choices for recovering PIP extension include serial static orthoses, serial casts, static progressive orthoses, and dynamic orthoses. These may be prefabricated or custom-made and digit-based or hand-based. The goal of the orthosis is to maximize the total end range time (TERT) in extension and achieve contracture correction without causing increased inflammation of the soft tissues around the PIP joint. Flowers proposes using a Modified Weeks Test to determine the best orthosis to address PIP joint stiffness.¹⁵ The orthosis selection process is based on how much contracture resolution is achieved after the joint is heated and stretched. PROM measurement is initially taken cold and prior to intervention. After ROM in a thermal modality and 10 minutes of end range stretch, a comparative measurement is taken:

• If there is a 20° change, no orthosis is recommended.

• If there is a 15° change, an end range static orthosis should be effective.

• If there is a 10° change, a dynamic orthosis is recommended.

• If change is less than 5°, a static progressive orthosis is recommended.

• The client should also participate in the orthosis selection process, because activities of daily living (ADLs) and work needs can influence compliance. Comfort, fit, and skin tolerance also all influence these choices.

• If full passive PIP extension is possible, a small PIP extension gutter or cast may be used. Adjust it as needed to accommodate resolution of edema and the client’s comfort. It is very important to keep the DIP free and to perform frequent exercises for DIP active and passive flexion while the PIP is splinted in extension.

• If ORL tightness is present, a gentle DIP flexion static progressive or dynamic orthosis may be appropriate. Ease of application and adjustability are criteria that help determine which type should be used.

• If the client has been cleared for active PIP extension and flexion exercises and if ORL tightness is present, try using a dorsal DIP gutter orthosis that maintains DIP flexion while actively exercising PIP extension.

Precaution. If ORL tightness is present, the client may be at risk of losing flexor digitorum profundus (FDP) excursion, and a quadriga effect could develop.

Clinical Pearls

After the client has been medically cleared for active PIP extension exercises, position the MP in flexion for the exercises. This can help isolate and achieve active PIP extension.

Check for intrinsic versus extrinsic tightness if composite flexion is limited, and prioritize the MP position accordingly for PIP exercise.

Precaution. As PIP flexion improves, watch closely for PIP extensor lag.

Precautions and Concerns

• Avoid PIP flexion during the protective immobilization phase.

• If the client has had surgery, follow the guidelines presented in Chapter 31. Instruct the client in techniques for supporting the digit while putting on and taking off the orthosis for skin care needs. If surgery was not required, instruct the client in ways to manage orthosis and skin care while avoiding PIP flexion. If a cast has been applied, change it at least weekly.