5. Anatomy of the Wrist
Carpal bones tightly linked by capsular and interosseous ligaments.
Capsular (extrinsic) ligaments originate from the radius and insert onto the carpus.
Interosseous (intrinsic) ligaments traverse the carpal bones.
The lunate is the key to carpal stability.
15. Lunate
Connected to both scaphoid and triquetrum by strong interosseous ligaments.
Injury to the scapholunate or lunotriquetral ligaments leads to asynchronous motion of the lunate and leads to dissociative carpal instability patterns.
16.
17.
18. Proximally articulates with
radius and TFCC
•Distally articulates with
capitate alone in 1/3 of
cases
•In the rest, articulates with
the hamate as well
28. majority of lunates have both dorsal & palmar
vessels & are thus as well vascularized as the other carpal bones; - neither singleintraosseous nor extraosseous disruption alone will cause avascular necrosis in these bones because of the rich external and internal anastomoses;
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48. Blood supply to the lunate may be a key factor in pathogenesis. Three patterns of extraosseous blood supply has been described for lunate. Multiple vessels, one volar and one dorsal vessel each and a single dorsal blood vessel in 7%. In addition 31% of cases showed single path of intraosseous supply through the bone with no significant arborization. Lunate with a single blood vessel supply may be at risk for avascular necrosis in presence of trauma.
Proximal portion of lunate is a terminal perfusion zone dependent on intraosseous retrograde blood supply. In Kienbock disease, the pathoanatomical changes show zone of necrosis in the proximal portion, zone of reparation in the middle layer with fibrovascular reparative tissue and zone of viability in the distal portion. Disruption of venous outflow has also been thought to be a cause of Kienbock disease.
49. 20% of lunate are supplied by a single artery and are therefore are at risk for avascular necrosis
50. Vascular Anatomy of the Lunate
The literature suggests that 7% to 26% of lunates may have a single volar or dorsal blood supply (type 1) and are therefore vulnerable to the development of AVN by disruption of extraosseous vessels alone (20). In other lunates, an extensive extrinsic blood supply or robust intraosseous connections require extensive disruption of extraosseous or intraosseous vasculature if AVN is to develop.
51. The anatomy and vascularity of the lunate:
considerations applied to Kienböck's disease.
52. Hand Unit and Upper Extremity, Department of Orthopedic Surgery, Hospital de la Santa Creu i Sant Pau, Autonomous University of Barcelona, Barcelona, Spain. clamasg@hsp.santpau.es
53. Abstract
PURPOSE:
The purpose of this study was to assess the anatomy and vascularity of the lunate.
54. METHODS:
they studied 27 cadaver upper limbs using latex injection and the Spalteholz technique. they investigated the blood supply to the lunate.
55. RESULTS
The nutrient vessels entered the lunate through the dorsal and volar poles in all the specimens. The dorsal intercarpal and radiocarpal arches supply blood to the lunate from a plexus of vessels located directly over the lunate's dorsal pole. Vessels entered the dorsal aspect of the lunate through one to three foramina. One to five nutrient vessels were observed entering the volar pole through various ligament insertions, including the ligament of Testut-Kuentz (radio-scapho-lunate (RSL) ligament) and the radiolunate triquetrum ligament (or dorsoradial carpal ligament) and ulnar lunate triquetral ligament.
58. CONCLUSIONS:
The lunate had consistent dorsal and palmar arteries entering the bone in all the specimens. The blood supply and foramina number is greater in the volar pole of the lunate than the dorsal pole. The lunate blood supply comes from different ligaments. In the etiopathogeny of Kienböck's disease it is possible that an acute or chronic, traumatic or non-traumatic injury of the vessel bearing ligaments, particularly because of their structure and the location of the RSL ligament, may have an important role in the appearance of lunate necrosis.
61. Articulations and ROM
Distal Radioulnar joint
Supination and Pronation – 80-90o
Ulna moves posteriorly and laterally with pronation
Radiocarpal joint (and Ulnocarpal joint)
Flexion (80-90o) and Extension (75-85o)
Radial (20o) and Ulnar (35o) Deviation
Intercarpal joints
Gliding
62. Soft tissue of Wrist
Ligaments
Covered by a fibrous capsule
Radial and ulnar collateral
limit ulnar and radial deviation; collectively limits flexion and extension
Intercarpal and Carpometacarpal
64. Soft tissue of Wrist
Cartilage
Triangular Fibrocartilage Complex – TFCC
“Meniscus” between ulna and triquetrum
Ulnar collateral ligament and palmar ulnocarpal ligaments have attachments
Compressed with Pronation and Extension
Compressed with Ulnar deviation
68. DEAFINATION
Idiopathic osteonecrosis of lunate
Stress or compression fracture of the lunate
Disruption of blood supply with collapse and secondary fragmentation
Pain and stiffness of the wrist in the ABSENCE of TRAUMA
69. Scapholunate Dissociation
Diagnosis often missed
Pain, swelling, and decreased ROM
Pressure over scaphoid tuberosity elicits pain
Greatest pain over dorsal scapholunate area, accentuated with dorsiflexion
X-ray shows widening of scapholunate joint space by at least 3 mm
70. History
AVN of the lunate, or lunatomalacia, was first described in cadaveric specimens by Peste in 1848 . He believed that the lunate changes were posttraumatic, secondary to fracture.
Kienböck described the characteristic findings of lunatomalacia in an x-ray in 1910. Six years later, Kienböck's name was ascribed to lunate AVN when Speed first termed the condition Kienböck's disease in his textbook (1916) .
71. HISTORY
First described by Peste in 1843
Described as lunatomalacia by Kienbock (1910)
Traumatic rupture of the ligaments and vessels
around the lunate produced lunate fracture with
subsequent collapse.
72. The etiology of Kienböck's disease
Multiple factors contribute to the necrosis of the lunate
Extrinsic Factors
Intrinsic Factors
73. Extrinsic Factors
Ulnar Variance
Geometry and BIOMECANICS of the Distal Radius
Trauma
Instability
Fracture
74. Ulnar Variance
Relationship of the distal articular surfaces of the
ulna and the radius seen on a PA X-ray of the
wrist
81. Ulnar Variance
Hulten noted that 74% of patients with Kienbock’s
had negative ulnar variance
In a normal population:
61% neutral ulnar variance
23% negative
16% positive
82. Normal ulnar variance
80% of load goes to the radius
Positive ulnar variance
in +2.5mm of ulnar variance 60% of load goes to radius while 40% goes though ulna
leads to ulnar sided wrist pain from increased impact stress on the lunate and triquetrum
associated conditions include
ulnar impaction syndrome
SLD
TFCC tears
lunotriquetral ligament tears
Negative ulnar variance
in -2.5mm of ulnar variance, 95% of load goes through radius and 5% of load goes through ulna
associated with Kienbock's disease
83. •Method to determine ulnar variance
•requires PA radiograph w/ wrist in neutral supination/pronation and zero rotation
•from the PA view draw two lines one tangential to the articular surface of the ulna and perpendicular to its shaft
•the other tangential to the lunate fossa of the radius and perpendicular to its shaft.
•measure the distance between these two lines.
•If the ulnar tangent is distal to the radial tangent there is positive ulnar variance, if it’s proximal there is negative ulnar variance. Normal is 0mm.
85. BIOMECANICS
90.3% of the radio-ulno-carpal force is transmitted
to the radius:
◦ 61% through radioscaphoid joint and
◦ 39% through radiolunate joint
9.7% through TFCC
86. BIOMECANICS
Load through the lunate depends on:
◦ Amount of bone that is not covered by distal radius and
◦ Ulnar variance
Schuind et al J Biomechanics, 1995
99. Vascular theory
◦ Primary circulatory problems,
e.g. Sickle cell disease/ raised venous
pressure
Mechanical theory
◦ Excessive mechanical loads cause
repeated microfractures and collapse
◦ Role of trauma
100. Kienbock Disease
Stage I – IV
Stage I: MRI only
Stage II: Sclerosis
Stage III: Some collapse
Stage IV: Total collapse
101.
102. Lichtman's Radiographic Classification of Kienbock's Disease
Stage I - Normal radiograph
Stage II - Sclerosis of lunate with possible decrease of lunate height on radial side only
Stage IIIa - Lunate collapse, no scaphoid rotation
Stage IIIb - Lunate collapse, fixed scaphoid rotation
Stage IV - Degenerative changes around the lunate
103. stage I
The radiographic changes that occur in Kienböck's disease tend to follow a pattern of progression beginning with fractures in the necrotic subcortical trabeculae of the lunate due to forces applied to it through the capitate
104. stage II
Absence of bone remodeling and the collapse of trabeculae lead to a relative increase in radiodensity in the lunate
106. stage IIIb
Collapse progresses until the joint compressive forces are attenuated by redistribution to the proximal scaphoid and triquetrum. The ulnar aspect of the lunate, which overlies the triangular fibrocartilage, is usually less involved than the portion articulating with the lunate fossa, due to the difference in compliance between the two surfaces. Loss of interosseous ligament connections due to fragmentation of bone may result in further carpal collapse and loss of normal intercarpal relationships
107. Loss of interosseous ligament connections due to fragmentation of bone may result in further carpal collapse and loss of normal intercarpal relationships
108. Bain & Begg Arthroscopic classification
Based on number of nonfunctional articular surface.
109. Based on number of nonfunctional articular surface.
0- Articular surfaces are normal
1- Proximal surface of lunate abnormal
2A- Proximal surface of lunate and lunate fossa of Radius abnormal.
2B- vertical fracture of lunate.
3- Lunate fossa of radius and proximal and distal surfaces of lunate abnormal.
4- Lunate fossa of radius and proximal and distal surfaces of lunate and the proximal surface of capitate abnormal.
110.
111. Schmitt and Lanz MRI patterns
N- Normal signal
A- Marrow edema with viable and intact bony trabeculae
B- Early marrow necrosis with fibro-vascular reparative tissue
C- Necrotic bone marrow with collapse
115. Initial symptoms
Initial symptoms include dorsal central pain, swelling, and limited wrist motion. These symptoms may be present for many months before the patient seeks medical attention.
116. Symptoms include dorsal wrist pain, weakness, and loss of wrist motion affecting extension more than flexion. Patients may also note dorsal wrist swelling and, on occasion, symptoms of carpal tunnel syndrome
121. More common in men
Peak incidence: 18-40 yrs
Most patients are involved in heavy manual labour
Typically unilateral
122. CLINICAL PRESENTATION
Insidious onset wrist pain
Beware of making a diagnosis of wrist sprain
Pain is aggravated with activity, relieved with rest
Weakened grip strength
Slightly reduced flexion and extension
124. Diagnosis
AVN on MRI - low signal on T1 & T2
MRI helps to differentiate Kienbocks from other causes of radiolucency in lunate
Bone scan : increased uptake
127. Choice of surgery depends on the stage of disease, range of movement of wrist, ulnar variance, shape of sigmoid notch and the presence of coronal fracture of lunate.
Treatment is mainly based on the stage of disease.
Treatment recommendations based of Lichtman’s classification
I – Immobilization
II &IIIA with negative ulnar variance- Radial shortening
II &IIIA with positive ulnar variance- Lateral wedge osteotomy of radius or Capitate shortening
IIIB- Proximal row carpectomy or triscaphe fusion
IV- Wrist arthrodesis
128.
129.
130. Treatment
Radiographic stage
Experience of the surgeon,
Desires and activity level of the patient,
Anatomic variation of the ulna,
And other radiographic, arthroscopic, or surgical findings such as disruption of lunate articular cartilage or extruded fracture fragments
131. In the early stages, efforts should be made to salvage the lunate and prevent loss of normal architecture.
132. In the later stages, efforts should be made to restore that architecture.
133. In the end stage, normal architecture must be sacrificed to restore function.
135. Nonoperative Treatment
is based on the principle of diminishing the forces responsible for the usual progression of lunatomalacia from ischemia to collapse and arthrosis
136. Hulten believed that early disease should be treated with immobilization for periods as long as 4 months
137. Kristensen recently compared immobilization with no treatment He found immobilization to be ineffective, with progressive lunate collapse in all wrists
138. In a recent long-term review of 25 cases treated by immobilization
, six patients had no pain,
but 14 had daily problems
seven had to change their occupation after a mean follow-up of 8 years
They concluded that nonoperative treatment of Kienböck's disease was ineffective. In most series, progressive collapse and continued pain have been the usual result of casting .
139. At present, immobilization is reasonable primarily in stage I disease, when spontaneous revascularization may possibly allow the lunate to heal. If pain persists, efficient treatment must be based on surgical methods
140. Surgical Treatment
Surgical treatment of Kienböck's disease can be divided into three broad categories:
1: Mechanical (lunate unloading),
2: Biologic (lunate revascularization),
3: Salvage therapy
141. Mechanical
Lunate Unloading
it would be reasonable to consider the use of external fixators or midcarpal pinning for a similar period.
142. Joint Leveling
An osteotomy to realign the radiocarpal joint by
shortening of the radius
Or lengthening the ulna
143. Radial Shortening
Radial shortening is generally preferred:
: No graft is needed,
:And the plate may be placed anteriorly where it is well covered by soft tissue and therefore less symptomatic.
An osteotomy in the metaphyseal region heals faster
Extraarticular nature of the procedure
144. Ulnar Lengthening
Ulnar lengthening is nearly equivalent biomechanically to radial shortening—2.5 mm of lengthening results in a marked increase in ulnocarpal load and diminution in radiolunate force
145. Capitate Shortening
Capitate shortening is a highly effective method for reducing lunate loading in cases in which a joint leveling procedure cannot be performed.
It does effectively unload the lunocapitate and radiolunate joints,
146. The method may be combined with a CH fusion (107) and has been reported to provide good results in patients with early Kienböck's disease with minor architectural changes in the aseptic lunate, no arthritic changes, and no ulnar-minus variance (107). The procedure may be performed as an adjunct to lunate revascularization
147. Intercarpal Fusions
Intercarpal fusion is another method used to diminish lunate loading or prevent or correct carpal collapse associated with stage III changes. Two limited fusions have been documented to unload the lunate (STT and SC) (Fig. 7). Another intercarpal fusion between CH has been reported to provide symptomatic relief in Kienböck's disease (108) but by an unknown mechanism, as its arthrodesis has no effect on carpal loading.
148. Scaphotrapeziotrapezoid
STT arthrodesis has been applied for the treatment of Kienböck's disease and has been demonstrated to diminish lunate compressive forces
150. Clinical studies have demonstrated that STT arthrodesis may provide good clinical results in Lichtman stage III
151. Scaphocapitate
SC arthrodesis is another procedure that is effective in modestly reducing lunate loading. A decrease of radiolunate joint force of approximately 10% to 12% has been measured, along with an 11% reduction in lunocapitate and ulnolunate forces
152. Capitate-Hamate
CH arthrodesis has been suggested by Chuinard for the treatment of Kienböck's disease . Clinical reports of the method suggest that it is effective in alleviating patient symptoms
153. Lunate Revascularization
Lunate revascularization is an example of one form of therapeutic intervention, termed surgical angiogenesis. It is defined as the surgical transfer of vessels or well-vascularized autogenous tissue, used alone or augmented by simultaneous application of vasculogenic cytokines
154. In orthopedic practice, both implanted AV bundles and vascularized pedicle or free bone flaps (grafts) have been used in the specific case of osteonecrosis
155. Vascularized Bone Grafts
Vascularized pedicle bone grafts have been used in cases of aseptic necrosis of the scaphoid proximal pole nonunion fragment, AVN of the scaphoid (Preiser's disease), and Kienböck's disease.
156. applied to carpal pathology have been described by many investigators and have been transposed from the pisiform, palmar and dorsal radial metaphysis, second metacarpal head, the metaphysis of the radil or ulnar shaft
157. To be successful, all vascularized pedicle bone grafts must have a pedicle of sufficient length to reach the recipient site without tension. Second, the vascular pedicle should ideally include nutrient vessels that supply both cortical and cancellous bone. Finally, the vessels must have sufficient blood flow, regardless of diameter, to maintain bone viability
158. Vascularized Pedicle Bone Grafts from the Dorsal Distal Radius
The application of dorsal distal radius vascularized pedicle bone grafts based on the anatomic studies of Sheetz et al. was recently reported (86,87,153).
In Kienböck's disease, revascularization with a vascular bundle or vascularized bone graft can be performed even in advanced (stage IIIb) cases, provided that an intact cartilage shell is present (i.e., without fracture or fragmentation) and no arthrosis is found. Revascularization is a logical alternative to load-altering procedures and is especially attractive in ulnar-neutral or -positive variance cases when radial shortening is contraindicated. Contraindications include stage IV disease and lunate fracture with extrusion or separation of fragments.
159. Two are superficial to the extensor retinaculum, supplying nutrient branches to the bone underlying bony tubercles between extensor tendon compartments. They are aptly named the 1,2 and 2,3 intercompartmental supraretinacular arteries (1,2 and 2,3 IC SRAs), the numbers denoting the extensor compartments
160. they pass between. The other two are deep vessels, located on the floor of extensor compartments, named the fourth and fifth extensor compartmental arteries (4th and 5th ECAs) for their specific anatomic location in the radial aspect of each compartment. The 1,2 IC SRA courses from the radial artery 5 cm proximal to the radiocarpal joint beneath the brachioradialis muscle to emerge on the dorsal surface of the extensor retinaculum. In the anatomic snuffbox, the 1,2 IC SRA anastomoses with the radial artery or the radiocarpal arch.
161. This vessel, based on its distal anastomotic connection to the radial artery, is the “ascending irrigating branch” described by Zaidemberg et al. (156). It is important to recognize that the vessel actually lies superficial to the extensor retinaculum rather than on the periosteum, as originally described. The 2,3 IC SRA originates from the anterior interosseous artery or the posterior division of the anterior interosseous artery.
162. It lies superficial to the extensor retinaculum directly over Lister's tubercle and anastomoses with the dorsal intercarpal arch, the dorsal radiocarpal arch, or the 4th ECA. Its nutrient artery branches penetrate deeply into cancellous bone. Like the 1,2 IC SRA, the 2,3 IC SRA can be easily harvested and used as a vascularized pedicle bone graft. The arc of rotation is greater and can reach the entire proximal row, making it useful for either Kienböck's disease or scaphoid nonunions.
163. Technique of Harvest: Fourth and Fifth Extensor Compartmental Graft
In the 4th and 5th ECA graft, retrograde flow from the 5th ECA is directed in an orthograde direction into the 4th ECA by ligation of the posterior division branch of the anterior interosseous artery proximal to the vessels' origin.
164. Unloading of the lunate is important during the revascularization process and may be accomplished by temporary unloading with an external fixation or temporary pinning of the midcarpal joint.
165. Results of Vascularized Bone Grafts for Kienböck's Disease
Lunate revascularization techniques have demonstrated promising clinical results for Kienböck's disease. Most series report excellent pain relief with improvement in range of motion and strength. Radiographic progression of lunate and carpal height collapse occurred in 0% to 15% of patients in recent studies (86,87 and 88), and radiographic and MRI evidence of revascularization is evident after surgery.
166. Lunate revascularization is especially attractive in ulnar-positive or -neutral Kienböck's disease, when joint leveling procedures are contraindicated. In these cases, the collapsed lunate may be gently expanded with the graft to improve the overall carpal height ratio and lunate index. Its use in ulnar-minus variant wrists is also reasonable, either alone or in combination with a leveling procedure.
167. Salvage Procedures
. Treatment in these instances requires the use of a salvage procedure rather than the unloading or revascularization options discussed above. Procedures useful in these circumstances include proximal row carpectomy, lunate excision with or without intercarpal fusion, lunate interposition arthroplasty with a variety of artificial or natural materials, and wrist arthrodesis.
168. Proximal Row Carpectomy
In symptomatic stage IIIb or IV Kienböck's disease, proximal row carpectomy may be considered, provided the capitate head and lunate fossa of the radius are in good condition. The need for concomitant radial styloidectomy is assessed intraoperatively after removal of the proximal row. Proximal row carpectomy was introduced in 1944 by Stamm, who used it in part for Kienböck's disease patients (168). Its use is still advocated today (169).
169. Lunate Excision
Simple excision of the lunate without replacement may achieve satisfactory pain relief at times (170). Resection arthroplasty is an alternative for patients
Either SC or STT arthrodesis will maintain carpal height and prevent or correct scaphoid rotary subluxation, which would be likely after lunate resection.
170. Lunate replacement
Lunate replacement has a long history, starting with vitallium prostheses, described by Lippman in 1949 (171), and acrylic materials (172). Silastic lunate arthroplasty was later popularized by Swanson, followed by titanium implants. Subsequent reports of particulate silicone causing foreign-body reactive arthritis and continued problems with carpal instability have led most surgeons to abandon this technique
171. total wrist arthrodesis
For patients with generalized carpal arthrosis (stage IV Kienböck's disease) or unsuccessful previous reconstructive surgeries, total wrist arthrodesis is the most reliable procedure for pain relief. Partial wrist denervation by transection of the articular branches of the posterior or anterior interosseous nerves (169) or complete wrist denervation (182) may be a useful adjunct to these procedures. In a recent report, either method provided substantial pain relief in Kienböck's patients (183). Total wrist arthroplasty is contraindicated in these generally young and active patients
