Mark Goleski and Jeffrey Lawton
DEFINITION
The laymen's term “jammed finger” often is used to indicate an injury sustained to the proximal interphalangeal (PIP) joint. If the force behind this injury is sufficient, the joint may suffer a fracture-dislocation, an injury that may be difficult to treat.
PIP fracture-dislocations in the dorsal direction is caused by disruption of the volar fibrocartilaginous plate, fragmentation of the middle phalanx where it attaches to this plate, and damage to the collateral ligaments on each side of the joint. Instability with dorsal displacement of the middle phalanx may result, accentuated by the unbalanced pull of the central slip.
Stiffness, pain, persistent subluxation, osteoarthritis, and permanent dysfunction are common sequelae, even with dedicated treatment in the best of circumstances.
Dynamic external skeletal traction, extension block splinting or pinning, transarticular pinning, open reduction with internal fixation (ORIF), and volar plate arthroplasty are the techniques most often used to address this problem.
None of these techniques have proven to be satisfactory for all patients in all instances.
Extension block pinning has been used with reasonable success to reduce and stabilize unstable PIP fracture-dislocations.
A K-wire is placed into the head of the proximal phalanx, mechanically blocking full extension and thereby preventing dorsal subluxation of the middle phalanx.
The advantages of this technique include its simplicity and the early mobility it affords an injured joint. It can be used alone or in combination with volar plate arthroplasty or ORIF.
ANATOMY
The PIP joint acts mostly as a hinge joint in the sagittal plane, although it does possess a few additional degrees of motion in the coronal and axial planes.17 It has an average range of flexion–extension of 105 degrees.16
The joint has a great deal of stability throughout its range of motion.16
When healthy, the joint is most stable in full extension.
A tongue-and-groove structure, formed by the bicondylar head of the proximal phalanx and the reciprocal concave surfaces of the middle phalanx, contours closely in this position.16
As the joint flexes, the ligamentous elements take up responsibility for maintaining stability.16
The volar plate, a structure that is ligamentous at its origin on the proximal phalanx and cartilaginous at its insertion on the middle phalanx, and the two collateral ligaments, one on the radial and one on the ulnar side of the joint, are the most important (FIG 1).
Two out of three of these structures must be impaired for displacement of the middle phalanx to occur.
PATHOGENESIS
Although the PIP joint may become dislocated in any direction, displacement of the middle phalanx dorsally is the most common.
Simultaneous hyperextension and compression forces—such as those seen when a ball strikes the tip of the finger—stress the volar plate and the collateral ligaments.
Type I injury
If the force of injury is mild, partial disruption of the collateral ligaments and the volar plate at its distal insertion on the middle phalanx are the only consequences.
The articular surfaces remain intact and the joint is stable.
If appropriate treatment is initiated promptly, an excellent long-term result is anticipated.13
Type II injury
If the force of injury is more substantial, bilateral longitudinal splitting of the collateral ligaments may occur in addition to rupture of the volar plate. Complete dorsal displacement of the middle phalanx is then possible due to unopposed pull of the central slip.
The joint can be readily reduced and usually is stable following the reduction.
Type III injury—stable
If an avulsion fracture of the middle phalanx occurs at the attachment of the volar plate, the joint may still remain stable. When less than 30% to 40% of the joint surface is involved, the joint is stable following reduction because collateral ligament integrity is maintained.4,15
Type III injury—unstable
If the fracture at the base of the middle phalanx involves more than 40% to 50% of the articular surface, collateral ligament support is lost. The joint exhibits persistent dorsal subluxation of the middle phalanx due to unopposed pull of the extensor tendon and lack of volar restraints.
FIG 1 • Anatomy of the proximal interphalangeal joint.
Closed reduction may not be possible, and treatment is more difficult, often leading to unsatisfactory overall results.20
NATURAL HISTORY
The outcome following even a minor injury is often less satisfactory than the patient anticipates. Although it is possible for a PIP joint that has suffered a fracture-dislocation to regain fully normal function, this often is not the case. Persistence of a stiff joint with a cosmetically thickened outline is common.
Delay in treatment or lack of vigilant care negatively affects outcome.10
Prolonged immobilization of the joint following reduction leads to stiffness. Early mobilization can avoid stiffness and promote nutrition of the damaged articular cartilage.19
Patients should be reassured, however, that carefully planned treatment and compliance with the postoperative therapy regimen leads to long-term satisfactory results in most cases.10
PATIENT HISTORY AND PHYSICAL FINDINGS
The history should elicit the manner in which the digit was injured, the nature of any medical treatment or manipulation of the digit before the current visit, and how much time has elapsed since the injury.
The likelihood of a favorable result diminishes with increased time from injury, particularly beyond 6 weeks.9
The digit will look surprisingly normal at presentation in many cases, particularly if it was previously reduced.
A transverse skin injury on the volar side of the PIP joint may indicate that the volar plate has been disrupted.25
The integrity of the neurovascular status should be documented on examination before digital anesthetic block and reduction.18
With the forearm supinated and the hand relaxed, observe the position of the patient's fingers. Note the axial and rotational alignment of the digit.
The uninjured, quiescent hand has increasing flexion tone in the digits from the radial side to the ulnar side,2 a phenomenon known as the flexion or resting cascade (FIG 2A).
Observe the patient's fingers directly and fluoroscopically as he or she attempts to move them through a normal range of motion. Dorsal subluxation often can be detected visually and through palpation.
Digital or wrist block anesthesia can be used to relieve discomfort associated with motion (FIG 2B).
If the joint can be moved through a full arc of motion without subluxation, adequate joint stability remains, and only brief immobilization will be required.
If redisplacement occurs, significant instability results. The position of redisplacement is a clue both to the specific site of ligament injury and the optimal position for joint immobilization.8 Loss of active extension implies central slip injury.
For grossly stable digits, manipulate the joint passively through the normal range of motion. Gentle lateral and dorsovolar shearing stresses are applied at full extension and at 30 degrees of flexion. The findings are compared to those of the contralateral uninjured digit (FIG 2C).
The position of the PIP joint at the point of instability suggests which of the soft tissue supports has been injured. Instability at more than 70 degrees of flexion indicates damage to the collateral ligaments. Instability in extension indicates disruption of both the collateral ligaments and the volar plate. The degree of joint laxity suggests the extent of injury to the ligaments, from microscopic tearing to complete rupture.
Palpate the PIP joint from all sides to determine point tenderness. Point tenderness often is valuable in localizing the injured structure.
Absence of point tenderness on the condyles may rule out significant injury to these structures. If the volar lip of the middle phalanx has been fractured, minor tenderness over the dorsum of the middle phalanx and greater tenderness volarly and laterally will be present.5
IMAGING AND OTHER DIAGNOSTIC STUDIES
Obtain anteroposterior, lateral, and oblique radiographs of the injured digit. Assess the digit for joint dislocation, subluxation, and fracture.18
Evaluate the radiographs before performing the physical examination to detect potentially unstable fractures or dislocations before they are manipulated.18
Radiographs of the hand as a whole (eg, the “fanned four-finger lateral” view) are not adequate. Subtle fracture-dislocations may be missed due to poor depiction of the areas of suspected pathology.23
Fluoroscopy is extremely valuable in defining the pathoanatomy and determining stability.
FIG 2 • A. Disruption of resting flexor cascade. B. Digital block technique. C. Passive stability evaluation.
CT scanning occasionally is indicated, particularly to assess suspected articular depression.10
DIFFERENTIAL DIAGNOSIS
Fracture
Fracture-dislocation
PIP dislocation
Collateral ligament and PIP joint sprain
PIP volar plate injury
PIP joint infection
Localized soft tissue infection
Flexor digitorum profundus tendon rupture
Extensor tendon central slip injury
Closed pulley rupture (flexor sheath)
Swan neck/boutonniere deformity
NONOPERATIVE MANAGEMENT
Most type I, type II, and type III stable injuries (and some type III unstable injuries) are amenable to nonoperative treatment.
The joint can be immobilized for a short time to afford the patient comfort and to allow soft tissue recovery.
A dorsal splint is applied to the digit at 20 to 30 degrees of flexion, avoiding immobilization beyond 30 degrees to lessen the risk of flexion contracture.
The duration of immobilization reflects the minimum amount of time needed to effect healing and obtain joint stability. Type I injuries are immobilized for several days; type III injuries may be immobilized for up to 3 weeks.
Avoidance of prolonged immobilization and patient education are the most important aspects of this treatment, because stiffness and contracture are very common.
Extension block splinting allows early motion of a joint while preventing extension past an angle where instability is possible.7,12,13,21
First, the position in which the joint re-displaces is determined.
A length of aluminum splint is then bent to an angle 10 or 15 degrees greater than this point of redisplacement and secured to the dorsum of the hand with adhesive tape or as part of a short-arm cast. The hand is positioned with 25 degrees of extension at the wrist and 45 to 60 degrees of flexion at the metacarpophalangeal joint7 (FIG 3A,B).
If the angle of the splint is greater than 60 degrees, the arc of motion may be insufficient for the patient to achieve adequate flexibility, and it may be necessary to consider another treatment regimen.
An extension block splint made from two pieces of AlumaFoam (Hartmann International, Rock Hill, SC) and spanning only the finger itself is another option (FIG 3C,D).
The two Alumafoam pieces are held to each side of the PIP joint with adhesive tape and are bent such that they come into contact with each other at a particular degree of extension, thus preventing motion beyond that point.21
FIG 3 • A,B. Extension blocking splint. C,D. Alternative aluminum and foam extension blocking splint.
In general, extension block splinting is recommended for fractures involving less than 40% of the articular surface. Successful results have been noted, however, with fractures involving up to 75% of the joint.12
Following application of the splint, radiographs are taken to confirm satisfactory reduction, and the patient is encouraged to flex the finger as much as the swelling allows.
As the fracture-dislocation heals, the extension block splint is progressively adjusted toward full extension, usually during a period of 3 to 8 weeks.7 Weekly radiographs and splint adjustments are required.
In certain instances, the digit may be too short, stocky, or swollen for such treatment, or patient compliance and sophistication for such a regimen may be in question. In such a case, extension block pinning may be the better option.
Because of the possibility of recurrent subluxation, the use of conservative treatment must be matched with frequent and careful assessment of the joint. Serial radiographs should be obtained weekly to document continued reduction of the joint and progressive healing of any fractures.7
SURGICAL MANAGEMENT
Operative treatment is indicated for those unstable fracturedislocations in which closed treatment does not provide a congruent reduction of the joint. This includes most type III unstable injuries with fractures that involve more than 40% to 50% of the volar articular surface.
As noted earlier, many surgical options are available. The choice of procedure is based on the exact nature of the injury and the surgeon's comfort with each option.
Dynamic skeletal traction methods, which use the principle of ligamentotaxis to maintain concentric joint reduction, are especially useful when the fracture is significantly comminuted.1
These methods allow early active range of motion.
Drawbacks include the following:
Significant prowess on the part of the surgeon is required, as are close postoperative supervision and adjustment.
The external device may be cumbersome for the patient.
ORIF is especially useful when the avulsed volar fragment is large and minimally comminuted.11 If the joint is stabilized with transarticular pinning as part of the ORIF procedure, however, stiffness usually results.
Volar plate arthroplasty, or the use of the distal aspect of the fibrocartilaginous volar plate to resurface the comminuted volar articular surface of the middle phalanx, is another option that can be employed when comminution of the volar fragment makes other techniques infeasible.3 Most authors have reported reasonably favorable results, but residual stiffness and contracture have been reported as well.6
Simple reduction with transarticular pinning (with no attempt at articular reconstruction) may be useful in injuries with less than 40% articular involvement. Extension block splinting may be just as effective in these milder instances, however, and it enjoys a lower risk of joint contracture.10
Extension block pinning is a viable alternative for mild to moderately unstable fracture-dislocations under the following circumstances:
The fracture-dislocation cannot be reduced and stabilized effectively with an extension block splint.14,22,24
Patient compliance is uncertain.
The finger is too short or swollen to fit appropriately into an extension block splint.
It may be used alone or in combination with an ORIF or a volar plate arthroplasty procedure.3
Preoperative Planning
Before the operation, the patient should be provided realistic expectations regarding outcome.
He or she should be aware of the possibility that immobilization, splinting, and long-term rehabilitation may be necessary.
The patient should be instructed to keep the injured hand clean before the procedure and to avoid additional skin injury to minimize the potential for infection. Fingernails should be trimmed and cleaned and the hands thoroughly scrubbed with antiseptic soap before the operation.
Intraoperative decision-making often is necessary. The surgeon should be comfortable in the performance of a number of alternative procedures and should have the necessary equipment available should findings require an alteration in the original surgical plan.
Positioning
The method of preparing, draping, and positioning the upper extremity is the same as for most hand surgeries.
A well-padded, proximal upper extremity tourniquet is applied.
Approach
Because extension block pinning is a percutaneous technique, no approach is required.
TECHNIQUES
EXTENSION BLOCK PINNING14,22,24
The PIP joint is reduced by flexing the joint to 90 degrees and applying axial traction.
Concentric reduction of the joint is confirmed with fluoroscopy (TECH FIG 1A).
If an open wound is present or the joint cannot be manipulated into an acceptable reduction, such as may occur with soft tissue entrapment, open reduction becomes necessary.
Following reduction through either open or closed methods, and with the joint flexed 90 degrees or more, a smooth 0.035to 0.045-inch K-wire is placed percutaneously into the distal, dorsal aspect of the proximal phalanx across the dorsal lip of the base of the middle phalanx (TECH FIG 1B).
The wire is inserted in a retrograde direction, approximately 30 degrees off the long axis of the proximal phalanx.
When placing the K-wire centrally, hyperflexing the PIP joint prevents tethering of the extensor mechanism to the proximal phalanx, which would limit joint flexion. Alternatively, the K-wire can be placed to one side of the central tendon to avoid tethering the extensor mechanism.
The wire is guided with fluoroscopy through the shaft of the proximal phalanx and is left protruding from the head of the bone. Fluoroscopy is used to confirm a congruous joint reduction following the procedure.
The joint is then passively extended to the limit of the K-wire, and the reduction of the joint is again critically evaluated fluoroscopically (TECH FIG 1C).
If the joint continues to subluxate dorsally at extension, a V-shaped gap between the articular surfaces of the head of the proximal phalanx and the dorsal lip of the middle phalanx will be seen on radiograph.16
With the pin in this position (TECH FIG 1D), the patient will be able to move the finger actively but will not be able to extend the digit beyond the point where subluxation is possible due to mechanical blockage by the pin (TECH FIG 1E,F).
An arc of more than 60 degrees is ideal.
TECH FIG 1 • Dorsal block pinning. A. Fluoroscopic view confirms adequate joint reduction. Note that fracture reduction is not anatomic but is considered acceptable in this clinical scenario. B. Insertion of the retrograde K-wire with the joint hyperflexed to avoid tethering the extensor mechanism. C. Passive intraoperative extension of the joint to the level of the K-wire. The dorsal joint remains concentrically reduced. D. The K-wire is left protruding through the bone, and its placement is confirmed by fluoroscopy. E,F. The patient should be able to move the finger through an arc of about 60 degrees.
POSTOPERATIVE CARE
The patient should have a thermoplastic splint fabricated for protection and should begin a supervised program with a hand therapist 3 to 5 days after surgery.
Gentle active range-of-motion exercises are allowed immediately and should be encouraged in most cases.
If the injury is especially serious—eg, injuries that required volar plate arthroplasty or that contained significant comminution—immobilization for up to 2 weeks may be indicated.14
Pin care must be explained carefully and performed regularly.
The pin is removed 3 weeks after surgery, and vigorous active flexion and extension are encouraged. Reverse blocking is initiated.
Full extension should be limited for 1 additional week.14
Active and passive joint exercises, including dynamic extension splinting, is initiated after 6 to 8 weeks of therapy, until full motion is achieved.
Buddy taping or wrapping can be used, if added, longerterm protection is needed.
OUTCOMES
The outcome for intervention into PIP fracture-dislocations depends mostly on the severity of the initial injury.
Because few cases of extension block pinning used as the sole intervention are available in the literature, it is difficult to assess the long-term outcome of the procedure.
Inoue and Tamara14 reported the use of extension block pinning in 14 cases of fracture-dislocation of the PIP joint with an average fracture fragment size of 38% of the articular surface (range 25% to 60%). Ten patients regained full range of motion, and four patients regained a more limited range (89, 65, 64, and 40 degrees, respectively). The average ROM for all patients was 94.4 degrees.
The authors attributed the four cases with less satisfactory results to the use of a 60-degree extension block splint postoperatively in one patient and significant comminution in the other three patients.
Viegas24 reported the use of this technique in three cases of fracture-dislocation of the PIP joint. One case involved a 45% single fragment fracture seen 1 day postinjury and another a 35% comminuted fracture seen 17 days post-injury. Following pin removal and 1 month of passive and active exercises, both patients regained full range of motion. A third case involved a 75% comminuted fracture seen 2 days post-injury. The patient's ROM after pin removal was 30 to 65 degrees. Because the patient did not return for further care, no final outcome was available.
Twyman and David22 reported the use of this technique in two cases of fracture-dislocation of the PIP joint. The extent of injury in each patient was not specified, but quick recovery to satisfactory ROM in both patients was reported (20 to 100 degrees and 15 to 110 degrees, respectively).
COMPLICATIONS
Persistent pain and swelling
Stiffness
Flexion contracture and extensor lag
Redisplacement of the joint and persistent subluxation
Angulation and rotation of the middle phalanx
Weakness
Boutonniere deformity
Post-traumatic arthritis (not necessarily symptomatic)
REFERENCES
1. Agee JM. Unstable fracture dislocations of the proximal interphalangeal joint: treatment with the force couple splint. Clin Orthop Relat Res 1987;214:101–112.
2. American Society for Surgery of the Hand. General principles of management. In The Hand: Primary Care of Common Problems. New York: Churchill Livingstone, 1985:1–17.
3. Blazar PE, Robbe R, Lawton JN. Treatment of dorsal fracture/dislocations of the proximal interphalangeal joint by volar plate arthroplasty. Tech Hand Up Extrem Surg 2001;5:148–152.
4. Deitch MA, Kiefhaber TR, Comisar BR, et al. Dorsal fracture dislocations of the proximal interphalangeal joint: surgical complications and long-term results. J Hand Surg Am 1999;24A:914–923.
5. Dias JJ. Intraarticular injuries of the distal and proximal interphalangeal joints. In: Berger RA, Weiss AC, eds. Hand Surgery. Baltimore: Lippincott Williams & Wilkins, 2004:153–174.
6. Dionysian E, Eaton RG. The long-term outcome of volar plate arthroplasty of the proximal interphalangeal joint. J Hand Surg Am 2000;25:429–437.
7. Dobyns JH, McElfresh EC. Extension block splinting. Hand Clin 1994;10:229–237.
8. Eaton RG, Littler JW. Joint injuries and their sequelae. Clin Plast Surg 1976;3:85–98.
9. Eaton RG, Malerich MM. Volar plate arthroplasty for the proximal interphalangeal joint: a review of ten years' experience. J Hand Surg Am 1980;5:260–268.
10. Glickel SZ, Barron OA, Catalano LW III. Dislocations and ligament injuries in the digits. In Green DP, Hotchkiss RN, Pederson WC, et al, eds. Green's Operative Hand Surgery, ed 5. Philadelphia: Elsevier, 2005:343–388.
11. Green A, Smith J, Redding M, et al. Acute open reduction and rigid internal fixation of proximal interphalangeal joint fracture dislocation. J Hand Surg Am 1992;17:512–517.
12. Hamer DW, Quinton DN. Dorsal fracture subluxation of the proximal interphalangeal joints treated by extension block splintage. J Hand Surg Br 1992;17:586–590.
13. Incavo SJ, Mogan JV, Hilfrank BC. Extension splinting of palmar plate avulsion injuries of the proximal interphalangeal joint. J Hand Surg Am 1989;14:659–661.
14. Inoue G, Tamura Y. Treatment of fracture-dislocation of the proximal interphalangeal joint using extension-block Kirschner wire. Ann Chir Main Memb Super 1991;10:564–568.
15. Kiefhaber TR, Stern PJ. Fracture dislocations of the proximal interphalangeal joint. J Hand Surg Am 1998;23:368–380.
16. Kraemer BA, Gilula LA. Phalangeal fractures and dislocations. In Gilula LA, ed. The Traumatized Hand and Wrist: Radiographic and Anatomic Correlation. Philadelphia: WB Saunders, 1992:105–170.
17. Leibovic SJ, Bowers WH. Anatomy of the proximal interphalangeal joint. Hand Clin 1994;10:169–178.
18. Robinson ME Jammed finger. eMedicine web site. http://www.emedicine.com/sports/topic55.htm. Updated April 27, 2006. Accessed August 16, 2006.
19. Salter RB, Simmonds DF, Malcolm BW, et al. The biological effect of continuous passive motion on the healing of full-thickness defects in articular cartilage: an experimental investigation in the rabbit. J Bone Joint Surg Am 1980;62A:1232–1251.
20. Schenck RR. Classification of fractures and dislocations of the proximal interphalangeal joint. Hand Clin 1994;10:179–185.
21. Strong ML. A new method of extension-block splinting for the proximal interphalangeal joint. J Hand Surg Am 1980;5:606–607.
22. Twyman RS, David HG. The doorstop procedure: A technique for treating unstable fracture dislocations of the proximal interphalangeal joint. J Hand Surg Br 1993;18:714–715.
23. Vercillo AP, Squier RC, Ritland GD, et al. Finger dislocations in alcoholics. Conn Med 1987;51:293–295.
24. Viegas SF. Extension block pinning for proximal interphalangeal joint fracture dislocations: Preliminary report of a new technique. J Hand Surg Am 1992;17:896–901.
25. Zook EG, Van Beek AL, Wavak P. Transverse volar skin laceration of the finger: Sign of volar plate injury. Hand 1979;11:213–216.