Download MCPJ Disease

MCPJ Disease in Rheumatoid Arthritis
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Key joint to the function of the fingers
MCP joint is the most commonly affected joint in the rheumatic hand
more vulnerable to deforming forces as less stable than IPJ
classically deformity is
1. ulnar drift
2. volar dislocation
3. eventual articular damage
Anatomy
 a diarthrodial, condylar-type joint that allows flexion, extension, radial/ulnar
deviation, and circumduction
 normal range of motion of the MCP joint is from neutral to 90° of flexion
 some radial and ulnar deviation, which decreases with flexion and the associated
tightening of the collateral ligaments.
 asymmetric in both the coronal and sagittal planes
 radial condyle of the metacarpal head is larger than the ulnar condyle, which
causes the metacarpal head to slope ulnarly and proximally in the coronal plane,
especially in the index and long metacarpals.
 volar surface of the metacarpal head is longer and broader than its dorsal
surface, which accounts for the cam effect that tightens the collateral ligaments
when the joint is flexed
 Sagittal bands
o help extend the MCP joint through their insertion into the volar plate, and
they center the extensor mechanism over the joint
o ulnar sagittal bands are stronger and denser than the radial sagittal
bands
 Volar plate
o supports the MCP joint volarly and limits its extension
o membranous portion of the volar plate attaches to the metacarpal neck and
has more laxity than the cartilagenous distal insertion
o adjacent plates are interconnected by the fibers of the deep transverse
intermetacarpal ligament
o accessory ligaments extend from below the collateral ligament at the
metacarpal head to the volar plate and are thought to stabilize it
Aetiology
1. proliferative synovitis stretches the capsule and ligamentous structures of MCPJ
2. wrist deformity leads to radial collapse carpus, ulnar translocation and radial
deviation of metacarpus
 Factors responsible for volar subluxation
1. attenuated dorsal extensor expansion
2. attenuated accessory collateral ligaments and volar plate
3. dislocation of the extensor tendons into the valleys of the metacarpus
(acting as weak flexors)
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4. Intrinsic muscle contractures lead to a volar-directed force on the MCP
joint,
Factors responsible for ulnar drift
1. carpal collapse leads to radial deviation of the carpus and metacarpals –
intercalary collapse theory of Landsmeer
2. forces of pinch and gravity
3. ulnar deviating force of the displaced flexor tendons
4. pull of abductor digiti minimi
5. ulnar intrinsic tendon tightens and maintain deformity
6. attenuation of the weaker radial sagittal bands causes ulnar subluxation
of the extensor mechanism
7. asymmetry of the metacarpal head (larger radial condyle) leads to ulnar
deviation of the MCP joints with progressive flexion
Classification (Harrison)
Grade 1
Dislocation of the extensor tendon without medial shift
Grade 2
Ulnar drift and shift
Grade 3
Grade 2 + subluxation
Grade 4
Grade 3+limited passive extension (irreducible subluxation)
Surgery
Preventative or Reconstrutive
 synovectomy only potentially prophylactic tool
 reconstructive include soft tissue reconstruction and various types of arthroplasties
 arthrodesis is poorly tolerated at the MCPJ
Treatment Outline
Harrison grade 1:
1. synovectomy
2. intrinsic release
3. reef radial sagittal band +/- release of ulnar hood
Harrison grade 2
1. synovectomy
2. crossed intrinsic transfer
3. extensor relocation
Harrison grade 3/4
1. synovectomy
2. crossed intrinsic transfer
3. MCPJ arthroplasty
Synovectomy
 Trial of conservative management in most cases
o medical therapy, splinting, steroid injections (up to 3x)
 questionable as to whether synovectomy alters the progression of disease
 indicated with persistent synovitis and minimal joint destruction and deformity
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painful persistent synovitis is rare but is another indication
Technique
 dorsal incision
 expose the extensor and open between the extensor and capsule on the ulnar or
radial side
 can split the extensor
 intrinsic release if required done at this stage
 separate the dorsal capsule from the extensor, can be difficult
 transverse incision through the dorsal capsule
 remove the proliferated synovium
 do not close the capsule
 realign the extensor
 active motion 1-2 days post op and the dynamic splinting for 4 weeks
Combined synovectomy and soft tissue reconstruction
 considered when a candidate for synovectomy and showing early volar
subluxation and ulnar drift
 mar slow recurrence of deformity
 soft tissue reconstruction alone is rarely indicated
Contraindications
 have good hand function and are painfree despite severe deformity – treat with
conservative management with night splints and observation
Operative techniques
Intrinsic release
 dorsal incision
 identify ulnar intrinsic
 transect or a triangle of the oblique band and leave the transverse band to provide
MPJ flexion
 may need to release proximal phalanx insertion of dorsal interossei to obtain
adequate position of MPJ
 must also release Ab digiti quinti – a strong ulnar deforming muscle; make sure to
preserve FDQ.
Crossed intrinsic transfer
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shown to be beneficial and long-lasting
in principle release the ulnar intrinsics to IF MF RF and transferred to the radial
aspect of the adjacent fingers
o transfer of 1 palmar interossei and 2 dorsal interossei
o release at midportion of proximal phalanx
o sutured to radial collateral ligament in MCPJ extension and radial
deviation
o (suturing to lateral band of adjacent may cause a swan-neck deformity)
o ADQ is released
Extensor tendon relocation
 Aim to correct deformity, restore extension, and prevent recurrent dislocation
 longitudinal or transverse incision depending on number of fingers involved
 Options:
1. plicate the radial sagital bands if minimal subluxation and low change of
recurrence
2. Harrison technique - distally based segment of the extensor 5mm wide
and 4cm long freed to distal MCPJ. Passed thru a drill hole at dorsal cortex
of proximal phalanx
3. Modified Harrison – tendon passed through dorsal capsule from outside to
inside, then out through capsule and extensor on radial side and sutured to
extensor.
postoperative management for soft tissue procedures
 splint in extension initially
 move into dynamic splinting with exercises beginning within 1 week
 long term splinting important in preventing recurrence
MCPJ arthroplasty
Clinical
 Assess proximal joints
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o Deformities in the proximal joints should be corrected before distal
articulations are addressed - evaluation of the shoulder, elbow, and wrist is
necessary in candidates for MCP joint arthroplasty.
o Addressing the radial deviation wrist deformity is very important before
MCP joint arthroplasty because progression of ulnar drift at the MCP
joints after arthroplasty is inevitable in patients with significant wrist
involvement.
o In addition, distal radioulnar joint instability can result in attritional
extensor tendon ruptures.
Assess distal joints
o Unlike other distal joints, PIP joints may be treated either after or at the
same time as the more proximal MCP joints.
o Most surgeons prefer to retain motion at the MCP joints while gaining
stability and optimal position at the PIP level.
o Preferred approach is to perform MCP implant arthroplasties and
correct the PIP joint problems with either tendon reconstruction (for
flexible deformities) or arthrodesis (for fixed deformities).
Assess soft tissues
o Evaluate tendons for the presence of synovitis and potential rupture
o Tenosynovitis may limit the amount of tendon excursion, leading to
limited MCP joint motion.
o With concomitant extensor tendon rupture, synovectomy and extensor
tendon repair should precede MCP joint arthroplasty by 6 to 8 weeks
o Some perform both the MCP joint arthroplasty and the extensor tendon
reconstruction at the same time because it is difficult to tension the tendon
reconstruction properly when the MCP joints are dislocated
Indications
 painful deformity with destruction or subluxation of the joint and fixed
deformity that cannot be corrected with soft-tissue reconstruction alone
1) decreased arc of motion (≤40°)
2) marked flexion contractures with the joint fixed in poor functional position,
3) MCP joint pain with associated radiographic abnormalities
4) severe ulnar drift (>30°).
 Avoid in relatively young (<50 years) patient with a functional range of motion of
the MCP joint (active arc, 60° to 70°)
Contraindications
1. presence of vasculitis
2. poor skin condition
3. inadequate bone stock - Excessive erosion of the metacarpal head and proximal
phalanx or excessive fatty replacement of the cancellous bone may make
prosthetic fit unsuitable, and the implant may rotate
4. Types of arthroplasty
1. soft tissue interpositional arthroplasty – original (historical) method
2. linked(hinged) vs unlinked
3. constrained (ball in socket)
4. semiconstrained
5. unconstrained (anatomic)
a. surface replacements
b. primary challenges: joint stability, rebalancing of tendons, and
prevention of prosthetic loosening.
c. Advantage: limit bone resection and preserve the integrity of collateral
ligaments.
d. Preservation of bone stock and collateral ligaments maintains stability
while reducing axial torque at the bone-cement interface.
Swanson’s Implants
 the modified Swanson implant remains the most reliable and accepted for
replacement arthroplasty in the hand
 The flexible silicone rubber implant used for MCP arthroplasty differs in fixation,
articulation, and motion from other joint replacement prostheses
 do not function as true prostheses but serve as dynamic spacers to maintain the
joint alignment after resection
 pistoning or gliding of the implant within the medullary canal is thought to add
to the range of motion achieved by the arthroplasty and to disperse the forces
along the implant-bone interface
Other implants
1. Sutter silicone implant – higher fracture rates reported
2. Avanta SR
a. Metacarpal component CoCr
b. Phalangeal component UHMW polyethylene
3. Saffar implant
a. Noncemented semiconstrained titanium-polyethylene
4. Mathes
a. Polyacetalresin component and polyester distal component with a
screw for intramedullary fixation
5. pyrolytic carbon metacarpophalangeal SRA
a. synthetic material formed by the pyrolysis of a hydrocarbon gas
b. physical and mechanical properties fall between those of graphite and
diamond
c. has an elastic modulus similar to that of cortical bone
d. biologically and biomechanically compatible
e. in a long term study in MCPJ arthroplasty, they were associated with a
low rate of fracture, a low rate of revision, and a high rate of patient
satisfaction (Cook J Bone Joint Surg 1999)
Technique (Swanson’s)
 dorsal transverse incision is made at the junction of the metacarpal head and neck
 dorsal veins should be preserved to minimize postoperative digital swelling
 longitudinal incision on the ulnar aspect of the hood,
 Soft-tissue release to relocate the phalanx and to allow preparation of the bony
structures for insertion of the components.
o The collateral ligaments are released subperiosteally at their origins, and
the contracted ulnar intrinsic muscles, including the abductor digiti minimi
manus, are released with a blade.
o flexor digiti quinti is preserved because achieving active flexion
postoperatively in the small finger is most difficult.
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o in an attempt to preserve the function of the first palmar interosseous
muscle in pinch, some surgeons prefer not to release the ulnar intrinsic
muscle to the index finger.
o crossed intrinsic transfer does not significantly affect the outcome in these
patients
Metacarpal osteotomy is just distal to the origin of the collateral ligaments and
perpendicular to the axis of the metacarpal shaft
medullary canal of the metacarpal is reamed with a hand reamer.
A trial prosthesis is selected, and the largest prosthesis possible is fitted without
applying excessive force.
can be used with circumferential titanium grommets if there is adequate bone
stock (may protect rubber component)
proximal phalanx of the index finger is reamed in a supinated position to allow for
better tip pinch postoperatively
the proximal phalanx of the small finger is reamed in slight pronation to improve
grip
Two small (0.035 in) drill holes are made on the dorsoradial aspect of the
metacarpal neck for subsequent reattachment of the radial collateral ligament.
Results
 realistic expectations are important because patients are not likely to achieve full
range of motion of the MCP joint.
 In patients with a substantial extensor lag or ulnar deviation, the arc of motion
may be only minimally increased, but this will be in a more functional extended
position.
 Key and tip pinch also should improve because the index finger is brought over
into radial position.
 Ulnar deviation can be reliably corrected, although there is a tendency for some
ulnar drift to recur over the long term. Recurrent ulnar drift in 43%
 Pain relief is consistently documented in follow-up studies o
Rehabilitation
 Hand therapy at 1 week
 Dynamic extension splint for 6 weeks with night resting splint
 Night splint for 3-4 months
 Special attention to
1. LF as this is slow to achieve active flxion due to release of hypothenar
muscles
2. IF as this tends towards ulnar drift
Complications
 Silicone rubber MCP joint implants are associated with low rates of complications
 bone resorption surrounding the implant
o likely related to the immunogenic response of macrophages to silicone
rubber particulate debris.
o silicone particle disease does not appear to be a critical issue for silicone
MCP joint arthroplasty.
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Implant fracture rates average 2% of cases
o in most cases, does not require revision of the prosthetic component – most
report that patient has satisfactory function
Infection 0.1-1%
o most infections presented within 8 weeks of implantation.
o Staphylococcus aureus was the most common organism isolated.
Particulate synovitis and silicone-induced lymphadenopathy 0.1%
o occurred almost exclusively in fractured implants or in implants with
substantial signs of wear at removal.
Main Criticisms
1. poor range of motion
2. progression of ulnar drift
3. loss of bone