2729
DEFINITION
■
The finger metacarpophalangeal joint (MCP joint) is com-
monly and characteristically involved in inflammatory arthritis.
■
The MCP joint is often involved early in inflammatory
arthritis and usually presents with ulnar extensor tendon sub-
luxation resulting in ulnar deviation of the fingers.
■
Occasionally in systemic lupus erythematosus (SLE) radial
subluxation of the extensor tendon is seen.
ANATOMY
■
The normal MCP joint is a condylar joint that allows flex-
ion and extension as well as radial and ulnar deviation and a
combination of these movements. Normally there is 90 degrees
of flexion, although hyperextension can vary.
■
The stability of the MCP joint is provided by the radial and
ulnar collateral ligaments, the accessory collateral ligaments, the
volar plate, the dorsal capsule, and the extensor tendon (FIG 1).
■
The metacarpal head diameter increases in both the trans-
verse and sagittal planes and therefore has a cam effect, mak-
ing the collateral ligaments tight in flexion and lax in extension.
This allows more radial and ulnar deviation of the MCP joint
in extension.
■
The MCP joint collateral ligaments are asymmetric.
■
The ulnar collateral ligament is more parallel to the long
axis of the fingers.
■
The radial collateral ligament is more oblique.
■
This causes supination of the MCP joint with MCP joint
flexion.
■
The collateral ligament also resists volar-directed forces.
■
The volar plate is fibrocartilaginous distally and has a mem-
branous portion proximally. It limits MCP joint extension.
■
The transverse intermetacarpal ligament connects the volar
plates to each other.
■
The accessory collateral ligament connects the collateral lig-
ament and volar plate and keeps the volar plate close to the
volar aspect of the MCP joint throughout motion.
■
The A-1 pulley of the flexor tendon sheath is attached to the
volar plate.
■
The extensor digitorum tendon is maintained centrally over
the MCP joint by the transverse fibers of the sagittal band that
attach volarly to the volar plate and the intermetacarpal liga-
ment. This forms a sling mechanism. The ulnar sagittal band
is felt to be stronger and denser than the radial sagittal band.
■
There is usually no direct extensor tendon insertion into the
proximal phalanx. The proximal phalanx is extended through
the sling mechanism.
■
The lumbrical muscle originates from the tendon of the
flexor digitorum profundus and is volar to the intermetacarpal
ligament. It inserts into the lateral band.
■
There are three volar (which adduct) and four dorsal (which
abduct) interossei that have tendons that all pass dorsal to the
Chapter 77
Andrew L. Terrono, Paul Feldon, and Hervey L. Kimball III
Metacarpophalangeal Joint
Synovectomy and Extensor
Tendon Centralization in the
Inflammatory Arthritis Patient
Proximal phalanx
Extensor tendon
Flexor tendon
Flexor tendon sheath
Interosseous muscle
Metacarpal head
Collateral ligament
Intermetacarpal
ligament
Volar plate
Sagittal
band
Lumbrical
muscle
AB
FIG 1 • A. Normal anatomy of the
metacarpophangeal joint.
B. Abnormal anatomy seen in
inflammatory arthritis. The extensor
tendon is subluxated ulnarly.
2730
Part 6 HAND, WRIST, AND FOREARM • Section VIII ARTHRITIS
transverse intermetacarpal ligament. They have variable inser-
tions into the proximal phalanx and extensor mechanism.
■
The first dorsal interosseous almost always inserts com-
pletely into the radial side of the proximal phalanx of the
index finger.
PATHOGENESIS
■
The pathology of inflammatory arthritis begins with prolif-
erative synovitis.
■
Selective changes in static and dynamic stabilizers of the
MCP joint occur, resulting in alteration in the equilibrium of
the joint. The most common deformity produced is ulnar de-
viation of the fingers (FIG 2A).
■
Which comes first, the changes to the dynamic or static
stabilizers, is unclear and may vary.
■
The capsule, radial collateral ligament, and radial sagittal
band are stretched by the synovitis and allow the equilib-
rium to move toward ulnar deviation.
■
The accessory collateral ligament and the membranous
portion of the volar plate become lax.
■
The joint capsule becomes thinned and a defect in the dor-
sal capsule may occur.
■
With increasing ulnar deviation, the ulnar intrinsic muscle
shortens.
■
The intrinsic muscle contribution to the deformity is un-
clear. It may be a primary or secondary change. There is a
cycle that is set up as the MCP joint ulnarly deviates and the
extensor tendon acts as an ulnar deviator and may even act
as a flexor of the MCP joint.
■
The laxity of the volar plate and accessory collateral lig-
ament causes the flexor tendons to develop a mechanical
advantage and increased flexion force. This results in an
increase in the deformity.
■
The combination of changes to the capsule, radial collateral
ligament, radial sagittal band, accessory collateral ligament,
and the membranous portion of the volar plate and the in-
creased mechanical advantage of the flexor tendon is magni-
fied by the normal ulnar and volar slope of the metacarpal
condyles and allows ulnar deviation and volar displacement of
the proximal phalanx (FIG 2B).
■
The wrist may be a contributing factor to the development
of the MCP joint deformity, and this must be considered in
each case before correcting the MCP joint.
■
Radial deviation of the wrist can be a compensatory posi-
tion to the ulnar deviation of the MCP joints to allow the
fingers to line up with the forearm.
■
Ulnar deviation of the digit is more common in patients
with radial deviation of the wrist.
■
At first the deformity is correctable passively, but gradually
this mobility is lost and the deformity becomes fixed.
■
Articular cartilage changes progress from softening of the
cartilage to erosion with significant loss of cartilage and bone.
This contributes to the deformity.
■
Once there are significant cartilage and bone changes,
extensor tendon realignment alone, without joint resurfac-
ing, is not indicated.
■
The changes seen in SLE are secondary not to synovitis
but rather to alteration in the collagen that results in a
change in the equilibrium of the MCP joint and subsequent
deformity.
■
The finger deformity in SLE is often ulnar deviation, but
radial deviation is not uncommon.
■
In SLE it is easy to change one deformity to another (ie,
ulnar drift into a radial deviation deformity after surgery)
because of the global changes to the supporting structures.
■
Despite the MCP deformity becoming fixed, the articular
cartilage is usually preserved.
NATURAL HISTORY
■
The natural history of the MCP joint changes in inflamma-
tory arthritis is not known and is probably highly variable and
influenced by the new disease-modifying medications.
■
Mild ulnar deviation of the fingers is normal and increases
with MCP joint flexion.
■
In inflammatory arthritis, such as rheumatoid arthritis, de-
formity is initially passively correctable.
■
Mild ulnar deviation of the fingers is seen in less than 10%
of the patients in the first 5 years of having rheumatoid
arthritis.
3
FIG 2 • A. Radiograph of a patient with extensor tendon
subluxation and ulnar deviation of the metacarpophalangeal
(MCP) joints. The joint spaces are maintained and the joints
are not subluxated. B. Radiograph of a patient with extensor
tendon subluxation and ulnar deviation of the MCP joints with
reducible MCP joint subluxation involving the index and
middle MCP joints.
A
B
■
Ulnar deviation has been reported in 30% of patients with
rheumatoid arthritis, with palmar subluxation in 20%.
3
■
Palmar subluxation almost always occurs with ulnar
deviation.
3
PATIENT HISTORY AND PHYSICAL
FINDINGS
■
In a patient with inflammatory arthritis who is being con-
sidered for MCP joint surgery, the entire upper extremity is
evaluated. Involvement of the lower extremities must also be
considered, given that the upper extremities may need to
assist in ambulation.
■
The need to use the upper extremities for weight bearing
can significantly affect the durability of the correction ob-
tained after MCP joint surgery.
■
Ideally MCP joint surgery is performed when the upper
extremity is not needed for such support.
■
The wrist is evaluated for the presence of a static deformity
at the time of MCP joint surgery. Presence of a static radial
deviation deformity will negatively affect the results of MP
joint surgery.
■
The skin over the MCP joint is evaluated; it should be in
good condition.
■
Motion of the MCP joint is assessed. The surgeon should
specifically ensure that ulnar deviation and flexion deformities
can be easily corrected passively.
■
Proximal interphalangeal (PIP) joint motion and alignment
must be critically evaluated.
■
If there is a significant boutonnière deformity, this should
be corrected before the MCP joint surgery since the PIP flex-
ion will influence the amount of MCP joint flexion obtained
postoperatively.
■
If there is a swan-neck deformity, this can be treated at
the same time or after the MCP joint. A stiff PIP joint in
extension will cause the patient to flex the finger at the MCP
joint and can help obtain better flexion postoperatively.
■
Any radial or ulnar deformity at the PIP joint must be cor-
rected before the MCP joint surgery.
■
The flexor and extensor tendons must be intact before any
MCP joint surgery.
IMAGING AND OTHER DIAGNOSTIC
STUDIES
■
Radiographs of the hand and wrist are essential before
MCP joint surgery to evaluate alignment, congruence, and
joint integrity.
DIFFERENTIAL DIAGNOSIS
■
The most common cause of inflammatory arthritis that
affects the MCP joint is rheumatoid arthritis.
■
SLE is more common in black women, and the deformity is
secondary to a collagen abnormality causing ligament and ten-
don imbalance. Articular cartilage loss is a much less common
problem in SLE. Soft tissue realignment can be performed even
after the condition has been present for a long time.
■
Psoriatic arthritis is more common in men and has a charac-
teristic skin rash, although patients may have joint involve-
ment before a clinically obvious skin rash. The patient with
psoriatic arthritis often has an asymmetric deformity and more
stiffness. The cartilage and bone are also affected.
NONOPERATIVE TREATMENT
■
A team approach to patients with inflammatory arthritis is
important.
■
Splinting in a corrected position (FIG 3) and joint protection
may decrease the forces that contribute to the deformity.
■
This may be helpful, but the effect in the long term is un-
known, and we have not noticed significant long-term benefit.
SURGICAL MANAGEMENT
■
One the most difficult operations to decide to perform is
MCP joint synovectomy and realignment.
■
This is usually best performed early when there is minimal
deformity.
■
However, at this time the patient often has minimal pain
and only slight loss of function.
■
With the use of disease-modifying medications, if the
anatomy can be restored and the mechanical problems cor-
rected, salvage procedures may be prevented or significantly
delayed.
■
The ideal patient for surgery is one with increasing defor-
mity and good medical management with control of his or her
synovitis.
■
The deformity should be passively correctable with good
active MCP joint motion.
■
Ideally the MCP joint is not volarly subluxated, since cor-
rection and maintenance of correction is more unreliable.
■
There should be a well-aligned wrist with good PIP joint
function without deformity.
■
If the deformity is passively correctable but cannot be
actively corrected, obtaining active ulnar deviation such as by
an extensor carpi ulnaris tendon relocation or transfer should
be considered.
■
The radiographs should reveal good preservation of the
joint space without volar subluxation.
■
If all of these criteria are met and the joints are not passively
correctable or there is volar subluxation of the MCP joint,
surgery can be performed, although the results may not be as
reliable.
2
■
A firm diagnosis can help with establishing a prognosis for
the maintenance of correction obtained at surgery.
■
The effect of the new disease-modifying medication is not
known.
Chapter 77 MCP JOINT SYNOVECTOMY AND EXTENSOR TENDON CENTRALIZATION IN THE INFLAMMATORY ARTHRITIS
2731
FIG 3 • A splint used to try to prevent progression of the ulnar
deviation. Usually this is not successful and ulnar deviation
eventually progresses.
2732
Part 6 HAND, WRIST, AND FOREARM • Section VIII ARTHRITIS
■
It is possible that the soft tissue correction obtained at
surgery may now last longer and therefore the procedure
should be entertained earlier and more often.
■
Ideally, earlier surgery will solve the correctable me-
chanical problem and will end the cycle of deformity.
Positioning
■
The procedure is performed using tourniquet control. The
hand is supported by a hand table.
Approach
■
The procedure usually is performed on all four fingers
through a transverse dorsal incision over the MCP joint
(FIG 4).
■
If a single digit is involved, a longitudinal incision should
be used.
■
If not all of the fingers are going to be corrected, the fingers
on the side of the deformity (ie, if there is ulnar deviation
deformity, the radial involved digits) must be corrected first to
limit recurrent deformity.
FIG 4 • A transverse incision is used to expose the metacar-
pophalangeal joints when performing an extensor tendon
centralization.
EXPOSURE
■
Expose the extensor mechanism at each joint (TECH
FIG 1A).
■
Release the juncture tendineae as needed (TECH FIG 1B).
■
Develop the interval between the extensor hood and
capsule.
■
Try to relocate the extensor tendon to the midline.
■
Sometimes this can be done without releasing the
ulnar sagittal band.
■
If the extensor tendon can be relocated to the midline,
expose the joint by incising the radial sagittal band.
■
The radial sagittal band will be reefed at the end of
the procedure.
■
If the extensor tendon cannot be relocated to the midline,
release the ulnar sagittal band to expose the capsule.
■
A central defect in the joint capsule is often present.
Open the capsule through this defect using a distally
based dorsal capsular flap (TECH FIG 1C).
TECHNIQUES
TECH FIG 1 • A. The extensor tendons are
exposed through a transverse skin incision. The
extensor tendons are subluxated ulnarly. B. The
juncture tendineae are released as needed.
C. The capsule is opened by creating a distally
based dorsal capsular flap.
A
B
C
Chapter 77 MCP JOINT SYNOVECTOMY AND EXTENSOR TENDON CENTRALIZATION IN THE INFLAMMATORY ARTHRITIS
2733
TECHNIQUES
SYNOVECTOMY AND TENDON REALIGNMENT
Extensor tendon
Ulnar collateral
ligament
Suture for
central tendon
Intrinsic tendon
Radial collateral
ligament
Lumbrical
muscle
■
Perform a synovectomy using small rongeurs, curettes,
and elevators (TECH FIG 2A).
■
Evaluate the intrinsics after the extensor tendon is relo-
cated and the joint is in neutral position. Perform an
intrinsic tightness test. If positive and intrinsic tightness
persists, release the ulnar intrinsics.
■
Incise the sagittal band and expose the intrinsic ten-
don on the ulnar side of the joint.
■
It is superficial to the collateral ligament and
capsule.
■
Pass a curved hemostat beneath the ulnar intrinsic
tendon as it inserts into the lateral band (see Fig 1)
and divide the tendon.
■
A section of the oblique fibers may be excised.
■
If intrinsic tightness continues, release the proximal
phalanx insertion by grasping the proximal portion of
the tendon with a clamp and sectioning (TECH FIG 2B).
■
A step-cut lengthening of the ulnar intrinsics may be
preferred to complete intrinsic release in patients
with SLE to avoid late radial deviation.
■
If the joint still cannot be corrected, release the ulnar col-
lateral ligament.
■
If the ulnar intrinsic has been released, an intrinsic trans-
fer can be performed, usually attaching it to the radial
collateral ligament (TECH FIG 2C).
■
The advantage of using the radial collateral ligament
as the attachment site is that it does not increase the
extensor force at the PIP joint, which could result in a
swan-neck deformity.
■
If the joint was subluxated volarly preoperatively, pin the
MCP joint in extension with a Kirschner wire.
■
After the proximal phalanx is reduced, reef or advance
the radial collateral ligament as needed (TECH FIG 2D).
■
Close the capsule in a pants-over-vest manner so that the
MCP joint is in extension (TECH FIG 2E).
■
The extensor tendon is relocated onto the dorsal midline
of the joint.
■
Strip the periosteum from the dorsum of the proximal
phalanx base and tenodese the central tendon to the
proximal phalanx using a suture anchor (TECH FIG 2F,G).
■
Alternatively, place two drill holes in the proximal
phalanx to suture the tendon directly to the bone.
■
2-0 PDS suture is used. Nonabsorbable suture may
result in prominent knots in this patient population
with thin skin.
■
Reef the radial sagittal band fibers with a 4-0 nonab-
sorbable suture to rebalance and support the extensor
tendon directly over the joint.
■
Repair the juncture tendineae.
■
Traction on the central tendon should result in full MCP
joint extension.
■
A bulky dressing with fluffs between the fingers is
applied, followed by a volar splint supporting the MCP
joints in extension and in a slightly overcorrected position.
TECH FIG 2 • A. A metacarpophalangeal joint
synovectomy is performed. B. The ulnar intrinsic
tendon is sectioned and the ulnar collateral liga-
ment is released. The central tendon is centralized
and sutured to the proximal phalanx. (continued)
A
B
2734
Part 6 HAND, WRIST, AND FOREARM • Section VIII ARTHRITIS
TECHNIQUES
1
2
2
C
D
E
F
G
TECH FIG 2 • (continued) C. The contracted ulnar sagittal fibers are released and the radial sagittal fibers are
reefed (red arrows) to rebalance and support the extensor tendon in the midline. The radial collateral ligament
is advanced (green arrow) and the ulnar intrinsic muscle is transferred to the radial collateral ligament (blue
arrow) of the adjacent digit. D. The radial collateral ligament is advanced, as in this case, or reefed. E. The
capsule is closed in a pants-over-vest manner so that the metacarpophalangeal joint is supported in extension.
F. The extensor tendon is sutured directly to the dorsal base of the proximal phalanx using absorbable suture.
G. Postoperative radiograph of a patient showing suture anchors in place after extensor tendon centralization.
PEARLS AND PITFALLS
■
Patient selection and control of the disease process are probably the most important factors.
■
Joints with fixed deformities and cartilage loss are best treated with replacement arthroplasty.
■
Proximal joint and distal joint correction must be performed before MCP joint surgery.
■
Intrinsic transfers do not improve the long-term outcome of this procedure.
■
Intrinsic lengthening is used only in patients with SLE.
Chapter 77 MCP JOINT SYNOVECTOMY AND EXTENSOR TENDON CENTRALIZATION IN THE INFLAMMATORY ARTHRITIS
2735
POSTOPERATIVE CARE
■
The postoperative dressing is removed at about 10 to 14
days and the sutures are removed.
■
An Orthoplast splint with the MCP joints extended and
slightly overcorrected, usually in slight radial deviation, is
applied until 4 weeks postoperatively.
■
At 4 weeks postoperatively, if Kirschner wires were inserted
they are removed. Splinting is then continued for 2 additional
weeks.
■
At 6 weeks postoperatively, hand therapy is started, concen-
trating on active MCP joint extension. Active MCP flexion
is also started. Protective splinting is continued for another
2 weeks in between exercises and at night.
■
The fingers are splinted together as a unit to maintain align-
ment and concentrate flexion at the MCP level.
■
To increase the postoperative flexion, the PIP joint is occa-
sionally splinted in extension, concentrating the flexion force
at the MCP joint.
■
Dynamic splinting can be used to support extension and
maintain digital alignment during the early healing stage but is
usually not necessary.
■
At 8 weeks postoperatively daytime splinting is decreased
and gradual return to functional activities is encouraged.
■
Nighttime extension splinting is continued for 3 months.
OUTCOMES
■
MCP joint extension and ulnar drift are improved post-
operatively.
■
MCP flexion is usually slightly less than it was preoperatively.
■
Strength is not significantly improved.
■
Maintenance of correction is usually good with slight in-
crease in ulnar drift, usually without recurrent subluxation.
■
When the deformity is seen early and is still passively cor-
rectable with preserved joints, extensor tendon centralization
and MCP joint synovectomy (as needed) is often beneficial,
improving patient function.
■
As with all joint procedures for deformities resulting from
inflammatory arthritis, the procedure itself does not stop the
progression of the disease. However, the new generation of
disease-modifying medications combined with surgery may re-
sult in long-lasting correction of joint deformity.
COMPLICATIONS
■
Infection
■
Wound healing problems
■
Loss of motion
■
Recurrent ulnar drift with tendon subluxation
■
Radial subluxation of the extensor tendon (seen in SLE)
■
Progressive joint destruction from the arthritis and need for
joint replacement
REFERENCES
1. Abboud JA, Beredjiklian PK, Bozentka DJ. Metacarpophalangeal
joint arthroplasty and rheumatoid arthritis. J Am Acad Orthop Surg
2003;11:184–191.
2. Nalebuff EA. Surgery for systemic lupus erythematosus arthritis of
the hand. Hand Clin 1996;12:591–602.
3. Wilson RL, Carlblom ER. The rheumatoid metacarpohalangeal joint.
Hand Clin 1989;8:223–237.
4. Wood VE, Ichtertz DR, Yahiku H. Soft tissue metacarpophalangeal
reconstruction for treatment of rheumatoid hand deformity. J Hand
Surg Am 1989;14A:163–174
