2. Anatomy
Present in the proximal carpal row
Distinguished by its deep concavity and crescentic outline
The etymology of the lunate bone derives from the latin luna
which means "moon", the lunate bone looks similar to a
crescent moon
3. The superior surface convex and smooth, articulates with the radius
The inferior surface is deeply concave, it articulates with the head
of the capitate and by a long, narrow facet (separated by a ridge
from the general surface) with the hamate
The dorsal and palmar surfaces are rough for the attachment of
ligaments.
4.
5. • AVN of the lunate was first described in 1843 by
Peste
• Robert Kienbock, a radiologist, described the x-ray
changes associated with lunatomalacia that is now
associated with his name
6. Blood Supply
Both a palmar and a dorsal blood supply are present in 74% to
100% of bones.[
single vascular blood supply in approximately 7% of lunates
33% have a single palmar and dorsal vessel for anastomosis
66% have a three-vessel anastomosis
10% have a four-vessel anastomosis
7. lunates with a single nutrient vessel, interruption may lead to
necrosis of the entire bone
a coronal fracture in these lunates can lead to avascularity of
the opposite pole
8.
9. Etiology
The origin and natural history of Kienbock's disease remain
unclear.
The loss of blood supply to the lunate has been attributed to
primary circulatory problems.
Traumatic interference, poor circulation, ligament injury
with collapse, and single or multiple fractures resulting in
secondary vascular impairment.
10. Kienbock's disease has been associated with
--scleroderma
-sickle cell anemia
-systemic lupus erythematosus
-corticosteroid use.
The cause of Kienbock's disease is multifactorial.
11. Hulten published his classic study comparing ulnar variance
in normal subjects and patients with Kienbock's disease
Gelberman and colleagues also described a significant
relationship between ulnar-negative variance and Kienbock's
disease
15. Schiltenwolf and colleagues studied the interosseous pressure
of the lunate with wrist motion.
They found that the interosseous pressure of the lunate is
greater in wrist extension than in neutral
The difference was greater by 40 mm Hg
This rise in intraosseous pressure may explain the lunate's
predisposition to osteonecrosis
16. Tsuge and Nakamura found that the radial inclination was
lower in patients with Kienbock's disease
Radial slope in the AP projection has a significant effect on
both the forces transmitted to the lunate and the patient's age
at the onset of Kienbock's disease.
17. Clinical features
Young males with pain and stiffness in the dominant wrist
Patients experience decreased grip strength
Insidious onset of dull pain centered over the radiolunate
joint
History of recent hyperextension injury
Pain aggravated by activity and relieved with rest and
immobilization.
18. Findings
Tenderness is centered over the dorsal lunate.
Patients may demonstrate a radiocarpal effusion with boggy
synovitis of the radiocarpal joint.
Range of motion of the wrist is limited.
Grip strength is decreased compared to the opposite side.
19. Investigation
Standard PA and lateral radiographs of the wrist neutral
rotation
MRI is the most sensitive imaging study for Kienbock's
disease
Bone scintigraphy may also show increased uptake in the
early stage of Kienbock's disease
20.
21. Radiographic findings of Kienbock's disease depend on the
staging of the disease
Increased bone density of the lunate is the early sign of
avascularity on plain radiographs
22. Typical radiographic findings
Lunate Sclerosis,
Progressive Loss Of Lunate Height,
Fragmentation Of The Lunate In The AP Direction,
Progressive Loss Of Carpal Height
Eventual degenerative joint
23. MRI will demonstrate a uniform decrease in signal intensity
on T1 radial images owing to the decreased vascularity
To make the diagnosis of Kienbock's disease, a signal change
must be seen throughout the entire lunate
25. Staging
The most common method for staging Kienbock's disease
was first described by Stahl in 1947
Lichtman and colleagues’ 1977 modification
This classification system is based on plain radiographs and
MRI findings.
Treatment is based on the stage of disease
28. stage I
Plain radiographs may be normal or a linear compression
fracture may be seen.
Lunate collapse has not occurred.
Diagnosis is usually made by MRI
MRI evaluation. A decreased signal on both T1- and T2-
weighted images suggests AVN.
Patients have intermittent dorsal wrist pain.
29. stage II disease
There is sclerosis of the lunate but no change in the size or
shape of the bone.
There may also be multiple fracture lines, but the lunate is
not collapsed.
The lateral radiograph is most sensitive for these early
changes.
Clinically, affected patients complain of pain, persistent
swelling, and stiffness of the wrist.
30. Stage III disease
stage IIIA, the lunate has collapsed but the carpus
remains unchanged, with normal alignment and
height.
Lateral radiographs show that the lunate is wider in
its AP dimension
31. In stage IIIB, the capitate has migrated proximally and the scaphoid
has assumed a flexed position.
As the carpal height ratio decreases, the lunate collapses and the
capitate migrates proximally
Scaphoid rotation produces a DISI pattern of carpal instability
Patients complain of progressive stiffness with diminished grip
strength.
Clunking with radial and ulnar deviation of the wrist may be
found.
32.
33. In stage IV disease
Continued carpal collapse is related to arthritic changes in
the radiocarpal and midcarpal joints.
Radiographs show subchondral sclerosis with joint space
narrowing, osteophyte formation, and degenerative cysts.
Patients complain of decreased range of motion to the wrist
with constant pain and swelling.
34. Treatment
Treatment algorithms for kienbock's disease have primarily
been determined by the stage of the disease.
Basically fall into three main groups:
- Procedures to unload the lunate
- Procedures to promote revascularization of the necrotic
lunate,
- Salvage procedures used when arthritic conditions exist.
35. Treatment
Non operative
mostly for asymptomatic patients
many studies for and against
Complication rates like lunate deformity and carpal collaspe
in many studies as high as 80% with non operative treatment
Not preferred in symptomatic patients
36. Stage I, II, or IIIA with Ulnar-Negative
Variance
Carpal collapse into an instability pattern has not occurred.
Salvage of the lunate is possible to maintain normal carpal
kinematics
In a symptomatic patient with stage I, II, or IIIA disease with
ulnar-negative variance, a joint-leveling procedure should be
considered
37. Authors have found that unloading the joint can be useful even in
patients with stage IIIB pathology
Radial-shortening osteotomy
Either a volar or dorsal approach
Locking forearm-shortening plates have been used
The goal is to leave the patient with ulnar-neutral or slightly
ulnar-positive variance
38. Joint-Leveling Procedures
Radial-shortening osteotomy is considered for patients with
Kienbock's disese who have an ulnar-negative variance and
no arthritic changes around the adjacent intercarpal or radio
carpal joints
39. Several biomechanical studies have compared the changes of
force distribution across the carpus.
Trumble and colleagues reviewed the force distribution
across the carpus with various procedures for kienbock's
disease.
40. Capitate-hamate fusion did not significantly decrease lunate strain
Ulnar lengthening, radial shortening, and STT fusion all produce a
70% decrease in lunate strain
Radial shortening -does not affect the final range of motion of the
wrist
Intra-articular procedures such as STT fusion, which limits wrist
radial deviation and extension
41. Trumble and colleagues noted that 90% of the reduction in
lunate strain following radial shortening or ulnar lengthening
occurred in the first 2 mm of length alteration
Strain reduction increased in both procedures with up to
3 mm of length alteration
Shortening greater than 4 mm runs the risk of incongruence
to the distal radioulnar joint
44. FOURTH AND FIFTH EXTENSOR COMPARTMENT
ARTERIES
The most useful vessels for vascularized bone grafting for
the treatment of Kienbock’s disease are the fourth and fifth
extensor compartment arteries.
A vascularized bone graft using the fifth ECA’s connection
to the fourth ECA by way of their common origin is
preferred because of the large diameter of the fifth ECA.
ECA pedicle provides an ideal pedicle length that can
reach anywhere in the carpus.
Other graft options include the 2,3 ICSRA graft based on
antegrade flow through the fifth ECA.
45.
46.
47. Technique Based on the Second or
Third Metacarpal
vascularized bone graft through a single midline incision
The pedicle may be mobilized in either an ulnar or radial
direction to a length sufficient to reach the lunate.
The bone graft is harvested from the base of the second or
third metacarpal, depending on where the artery has the
greatest area of contact
48. Stage I, II, or IIIA with Ulnar-Positive or
Ulnar-Neutral Variance
Capitate Shortening with Capitate-Hamate Fusion
Radial-closing radial osteotomy with reduction in the angle of
radial inclination
49. Stage IIIB
Salvage procedures should be considered
STT and scaphocapitate arthrodesis
Proximal row carpectomy has also been reported for stage IIIB
The lunate was excised and silastic lunate arthroplasty was
performed
The prevalence of silastic particulate synovitis led to the
discontinuation of the silastic prosthesis
51. Stage IV
There is significant collapse of the lunate in addition to
perilunate arthritis
Generalized degenerative changes are noted at the
radiocarpal and midcarpal joints
Proximal row carpectomy
End-stage kienbock's disease, wrist radiocarpal fusion is
recommended
