Proximal Interphalangeal Joint Injuries (PIPJ)

PIPJ injuries are common and may lead to significant pain, stiffness, instability and degenerative arthritis.

Ideal treatment involves achieving a stable congruent joint with early motion.

Anatomy

Hinge joint surrounded and stabilized by:

Volar plate - Proximally thin attachment, distally, lateral margins thickened creating socket for head of proximal phalanx.
Lateral and accessory collateral ligaments
Extensor expansion - inserts into base of the middle phalanx and also produces slips that become confluent with the intrinsic mechanisms. This confluence constitutes the lateral bands, which are connected to the volar aspect of a capsule by the oblique and transverse retinacular ligaments.

Assessment

Examine for areas of local tenderness palpate all above structures in turn

Asses joint stability, passive and active ROM (use digital block if pain prevents proper investigation)

Never assume lack of full flexion or active extension is due to pain. A closed rupture of the central slip may be missed until the boutonniere deformity develops.
Elson test for central slip rupture

From 90 degrees of flexion, patient actively tries to extend the PIP joint against resistance. The absence of extension force at the PIP joint, and fixed extension at the distal joint, indicate complete rupture of the central slip.

Radiography

AP
Lateral
Oblique - condylar fractures may be more evident on the oblique

NB. nutrient arteries in the region of the distal condyles of the proximal phalanx may mimic an undisplaced fracture. in children.

Treatment

Principles

Elevation
Early ROM - generally late problems are stiffness not instability
Most PIP joint injuries do not require open reduction.

Open reduction and internal fixation are indicated for:

Intra-articular fractures
Unstable fractures
Fractures that are stable only in flexion

Classification

PIPJ injuries fall into three categories:

Dislocations
Avulsion
Intra articular

Dislocations

Reducible vs Irreducible
Dorsal - commonest, simplest, rupture of volar plate and portion of collateral ligament , hyperextension force. Usually reducible and stable. Occasionally more complex and irreducible when component of torque force, the head of the proximal phalanx may be displaced between the volar plate and the flexor tendon and act as a buttonhole by tightly grasping the portion of the phalanx immediately behind the head, preventing closed reduction. Additionally, the distal attachment of the volar plate may rupture so that the volar plate becomes interposed between the joint surfaces. These dorsal dislocations require open reduction and repair, and subsequent active motion protected by "buddy taping" and an extension block movement commenced between 3 and 5 days postoperatively.
Volar- less common. NB central slip injury. Tend to be irreducible and unstable. Usually requires open reduction, after which the finger should generally be immobilized in extension for 7 days before active protective motion is commenced. In cases involving complete central slip rupture, repair should be followed by 3 weeks of PIP joint immobilization in extension. Unrecognized or inadequately repaired volar dislocation results in a chronic boutonniere deformity requiring later surgery, with generally poor late results.
Lateral - partial or complete tear of the collateral ligament complex Usually spontaneously reduce. Treatment debateable, some surgeons feel need surgical stabilization. Generally the joint is usually functionally stable after reduction, so the injury might be managed more conservatively. Minimize valgus or varus strain on the injured joint for 3 weeks by simple "buddy taping" Some cases may require open reduction if entrapment of an extensor tendon, or a collateral ligament in a joint, or buttonholing of the head of the proximal phalanx through a tear in the dorsal apparatus.

Avulsions

Small or large bony fragments
Dorsal - avulsion of insertion of the central slip of extensor mechanism into the dorsal base of the middle phalanx. If a large bony fragment is avulsed along with the central slip, the result is an unstable injury that should be referred for open reduction and fragment fixation. If there is no significant bony avulsion fragment, splint the PIP joint in extension for 3 weeks while allowing free movement of the distal and proximal joints. Followed by 2 weeks of buddy strapping. Missed diagnosis of central slip avulsion leads to progressive volar displacement of lateral bands, the central tendon heals stretched out, and secondary hyperextension at the PIP joint follows to produce a boutonniere deformity.
Volar - usually occurs at the insertion of the volar plate into the middle phalanx secondary to forced hyperextension or axial loading. This either ruptures the volar plate at the bone interface or avulses a fragment of the marginal metaphysis of the middle phalanx at the site of its attachment. Because the check ligament attachment of the volar plate to the proximal phalanx is strong and pliable, rupture seldom occurs here. This injury, although painful, is stable and often of minimal long-term consequence. Occasionally poor healing may lead to hyperextension at the PIPJ.
In the presence of any avulsed bony fragment, splinting in slight flexion (10 to 40 degrees) for 3 to 4 weeks, followed by buddy strapping for 2 weeks. In the absence of a significant fracture and in the slender finger, the injury is best treated by open repair with a pullout wire or a Bunnell suture dorsally over a button. These fingers should then be splinted in 30 to 40 degrees of flexion for 3 weeks followed by 2 weeks of active protected motion with buddy taping.
Lateral - avulsion may involve one or both collateral ligaments, treatment controversial, suggest buddy strapping for 3 - 4 weeks to minimize varus/ valgus strain.

Intra articular

The ideal treatment would include restoration of a stable and congruent joint surface that would allow early active range of motion.

Simple - one or two large bony fragments, tend to be unstable, internal fixation, is generally advocated, particularly in the presence of a large intra-articular fragment, marked obliquity, or a condylar fracture. Reduce open or closed and hold with K wires or mini fragment screws, followed by early ROM +- extension block splint.
Comminuted - Difficult fracture to treat, (Pilon fracture of base of middle phalanx). Treatment methods include, buddy strapping and early active motion, immobilization, extension block splinting, open reduction and internal fixation, external fixation, silicone prostheses, and fusion. Each of these methods has potential for advantages and disadvantages. It is important to bear in mind the goal of treatment is to avoid joint stiffness and loss of function, whatever treatment is chosen (see external fixation)

External Fixation

Several methods have been advocated from simple constructs to high tech fixators. The important steps are ensuring a congruent joint allowing early active movement of the PIPJ and avoiding pin site sepsis.

Deshmukh, S. C.; Kumar, D.; Mathur, K.; Thomas, B. Complex fracture-dislocation of the proximal interphalangeal joint of the hand: RESULTS OF A MODIFIED PINS AND RUBBERS TRACTION SYSTEM. JBJS - B Vol. 86-B(3):406-412, April 2004.

Freiberg, Arnis MD, FRCS(C), FACS. Pollard, Brian A. BSc. Macdonald, Michael R. MD, FRCS(C). Duncan, Mary Jean MD, FRCS(C). Management of Proximal Interphalangeal Joint Injuries. Journal of Trauma-Injury Infection & Critical Care. 46(3):523-528, March 1999

Halliwell, P.J.. The use of external fixators for finger injuries: PIN PLACEMENT AND TETHERING OF THE EXTENSOR HOOD. JBJS - B Vol. 80-B(6):1020-1023, November 1998.

SYED AA, AGARWAL M, BOOME R. Dynamic external fixator for pilon fractures of the proximal interphalangeal joints: a simple fixator for a complex fracture.
J Hand Surg [Br]. 2003 Apr;28(2):137-41

Giddins, G E B. Hynes, M C. DYNAMIC EXTERNAL FIXATION FOR PILON FRACTURES OF THE INTERPHALANGEAL JOINT. JBJS - B Vol. 82-B Supplement II:189, 2000.

Nine consecutive pilon fractures of the finger middle phalanx and one of the thumb distal phalanx were treated. Under local anaesthetic a 1.1mm Kirschner wire was passed transversely through the distal end of the proximal phalanx proximal to the joint capsule. A second 1.1mm Kirschner wire was passed through the middle phalanx parallel to the first wire, again perpendicular to the long axis of the digit. At a distance of 3-5mm from the skin surface, the proximal Kirschner wire was bent to 90° and the ends bent to allow the distal wire to be hooked into place holding the fracture out to length and allowing movement at the PIP joint. Finally the wires were bent to avoid dislocation . Physiotherapy was essential and was started as early as possible.

Krakauer, Joel D. MD. Stern, Peter J. MD. Hinged Device for Fractures Involving the Proximal Interphalangeal Joint. Clinical Orthopaedics & Related Research. (327):29-37, June 1996.