- See:
-
Dorsal Dislocation of PIP joint;
-
Extension Block Casting
-
Phalangeal Injury
- Discussion:
- long moment arm of the PIP joint, places this joint for higher risk of this injury;
-
mechanism and anatomy of injury:
- results from a jamming type injury or PIP joint hyperextension (which avulses the volar plate - either as a
ligamentous injury or as a palmar lip fracture);
- central slip of
extensor apparatus pulls middle phalanx dorsally & proximally;
- complete dorsal dislocation indicates disruption of volar plate (distal insertion) & accessory collateral ligaments;
- proper collaterals may remain attached to the middle phalanx and become lax as middle phalanx is displaced dorsally;
-
differential dx of pip injuries:
-
stable vs. unstable injuries:
- stable frx: small fracture w/ less than 40% of the middle phalanx base
- unstable frx: frx involves > 40% joint surface;
- palmar lip fracture
- dorsal lip fracture
- pilon fracture
- Radiographs:
- true lateral x-rays of the involved finger are manditory;
- radiographs can misleadingly suggest that very simple frx has occured w/ only small fragment of the bone involved;
- this fragment, however, is often the major attachment of a collateral ligament, the volar plate, or a tendon;
- this small frx may render joint grossly or potentially unstable;
- distinguish avulsion chip frx from frx dislocations w/ significant PIP joint involvement;
-
determine amount of articular involvement:
- when volar triangular frx frag of middle phalanx involves > 1/4 of articular surface, dorsal dislocation of middle phalanx may
occur late because the volar plate and a significant portion of the collateral ligaments are attached to the small fragment;
- base of middle phalanx may be frxed w/ upto 20 to 75% of joint involvement;
- frx dislocation may involve > 50% of articular surface, however, it is usually 20 to 40%;
-
volar plate remains attached to fracture fragment, & therefore accessory collateral ligaments,
volar plate, and fracture fragment maintain their normal relationships to each other;
-
V sign:
- indicates inadequately reduced joint in which joint surfaces are neither parallel nor congruent;
- a truly stable dislocation will not show instability in full extension;
- hinged flexion:
- this is a varient of the V sign in which congruent rotation of the joint is replaced by abnormal translation
across the flattened frx segments;
- Exam:
- following digital block anesthesia and reduction, have the patient actively move the joint and
assess for subluxation as the digit moves into extension;
- w/ palmar avulsion frx, note whether the injured digit permits hyperextension;
- if the digit is allowed to remain in hyper-extension, swan neck deformity may eventually occur;
- Non Operative Treatment:
- non operative treatment is generally indicated when there is less than 20-40 % of the palmar articular surface;
-
buddy taping:
- avulsion frx arising from volar plate injuries usually heals w/ non operative rx;
- reduction and brief splinting followed by buddy taping are indicated if anatomic reduction is maintained thru full ROM;
- buddy taping helps to prevent hyper-extension for otherwise stable fractures;
- it is important to not let the injured PIP joint fall into hyperextension, otherwise a swan neck deformity may result;
- if necessary, a paper clip can be incorporated into a Coband wrap inorder to prevent hyperextension;
-
extension block casting
- radiographs are required to determine the stable range of motion;
- typically, as the digit moves from flexion to extension, subluxation will be evident on x-ray;
- extension block spinting is used to prevent the digit from extending past the safe zone;
- after reduction, keep joint in at least 10-30 deg of flexion w/
extension block casting;
- w/ unstable dislocations, place joint in considerable flexion (about 75 deg);
- if x-rays show joint well reduced and congruent, apply dorsal block splint, & gradually decrease amount of flexion over 1 month;
- Indications for Operative Treatment:
- when the volar lip fracture of the middle phalanx involves 20-40% or more of the
articular surface, the remainder of the middle phalanx subluxes dorsally;
- this unstable injury requires more sophisticated treatment than simple volar plate avulsion;
- unstable joint following reduction;
- presence of bony fragment which blocks reduction;
- pilon fractures: typically result in severe stiffness with non operative treatment;
-
residual subluxation:
- manifested as the V sign on the lateral radiograph;
- indicates inadequately reduced joint;
- surfaces are neither parallel nor congruent;
- patients who are left with residual subluxation will most likely end up having a poor result;
- Operative Treatment:
- subluxation of the joint requires correction, but anatomic joint restoration is not manditory nor is it always possible;
- correction of joint subluxation also requires correction of abnormal joint hinging and gliding;
- anatomic reduction of comminuted volar lip fragments is not essential;
-
volar plate arthroplasty:
- volar plate is the chief stabilizer is dorsal dislocations / dorsal disolation-fractures;
- this procedure works best when the buttressing effect of the palmar lip remains intact;
-
extension block pinning:
- several techniques have been described;
- one technique involves insertion of a K wire into the head of the proximal phalanx with the remaining
end protruding enough inorder to block PIP extension;
- intradigital traction fixation device;
Fracture dislocation of the middle phalanx at the proximal interphalangeal joint: repair with a simple intradigital traction fixation device.
JS Gaul Jr MD and S. Nicolson Rosenberg.
American J. of Orthopaedics.
Oct 1998. p 682.
-
external fixation:
- provides distraction across the PIP joint and corrects residual dorsal subluxation;
- intradigital traction fixation device:
- technique relies on the fact that distaction most often will reduce the fracture and restore the joint anatomy;
- use 0.045 inch pins;
- one pin is inserted transversely thru the distal half of the middle phalanx;
- the other pin is inserted transversely through the proximal phalangeal head, and both ends are bent 90 deg so
that they are parallel to the middle phalanx;
- the distal ends of this pin are bent again about 5-8 mm distal to the first pin;
- a final bend is made about 5 mm distal to the previous bend;
- the second pin is used as the traction device, by hooking over the pin thru the middle phalanx;
- the patient is allowed PIP joint motion as tolerated;
-
open reduction without internal fixation:
- indicated for osteochondral frx dislocation, in which the osteochondral frx is gently replaced
back into the frx surface and the joint is carefully closed;
- no fixation is applied;
- ref: Surgical management of osteochondral fractures of the phalanges and metacarpals: A surgical technique.
VP Kumar et al.
J. Hand Surg. Vol 20-A. 1995. p 1028-1031.
-
arthrodesis:
- with operative management of PIP fracture dislocations, as a back up plan, patients should always be consented for arthrodesis;
- Complications:
- w/o proper care, joint becomes swollen, tender & unstable and eventually the joint will develop traumatic arthritis;
- major disability is not instability but stiffness and pain;
Extension block pinning for proximal interphalangeal joint fracture dislocations: preliminary report of a new technique.
The conservative management of volar avulsion fractures of the P.I.P. joint.
Unstable fracture dislocations of the proximal interphalangeal joint. Treatment with the force couple splint.
Year Book: Chip Avulsions and Ruptures of the Palmar Plate in the PIP
Unstable fracture dislocations of the proximal interphalangeal joint of the fingers: a preliminary report of a new treatment technique.
Agee JM.
J. Hand Surgery. Vol 3. 1978. p 386-389.
Management of fracture dislocation of the proximal interphalangeal joints by extension block splinting.
EC McElfresh et al. JBJS. Vol 54-A. 1972. p 1705-1711.
Fracture dislocations of the proximal interphalangeal joint.
TR Kiefhaber et al.
J. Hand Surg.
Vol 23-A. No 3. May 1998. p 368.
Fracture-dislocation of the middle phalanx at the proximal interphalangeal joint: repair with a simple interdigital traction fixation device.
JS Gaul Jr MD. and SN Rosenberg OTR/CHT.
The American Journal of Orthopaedics.
Oct. 1998. p 682.
