http://upload.orthobullets.com/topic/6050/images/keinbocksmri_figure3.jpg
http://upload.orthobullets.com/topic/6050/images/ulnar variance.jpg
http://upload.orthobullets.com/topic/6050/images/photo-1.jpg
http://upload.orthobullets.com/topic/6050/images/stage 1.jpg
Introduction
  • Avascular necrosis of the lunate leading to abnormal carpal motion
  • Epidemiology
    • incidence
      • most common in males between 20-40 years old
    • risk factors
      • history of trauma
  • Pathophysiology
    • thought to be caused by multiple factors
      • biomechanical factors
        • ulnar negative variance
          • leads to increased radial-lunate contact stress
        • decreased radial inclination
        • repetitive trauma
      • anatomic factors
        • geometry of lunate
        • vascular supply to lunate
          • patterns of arterial blood supply have differential incidences of AVN
          • disruption of venous outflow leading to increased intraosseous pressure
  • Prognosis
    • progressive and potentially debilitating condition if unrecognized and untreated
Anatomy
  • Blood supply to lunate
    • 3 variations
      • Y-pattern
      • X-pattern
      • I-pattern
        • 31% of patients
        • postulated to be at the highest risk for avascular necrosis
Classification
 
Lichtman Classification
Stage Description Treatment Image
Stage I No visible changes on xray, changes seen on MRI Immobilization and NSAIDS
Stage II Sclerosis of lunate Joint leveling procedure (ulnar negative patients) 
Radial wedge osteotomy or STT fusion (ulnar neutral patients)
Distal radius core decompression
Revascularization procedures
Stage IIIA Lunate collapse, no scaphoid rotation Same as Stage II above
Stage IIIB Lunate collapse, fixed scaphoid rotation
Proximal row carpectomy, STT fusion, or SC fusion
Stage IV Degenerated adjacent intercarpal joints Wrist fusion, proximal row carpectomy, or limited intercarpal fusion
 
Presentation
  •  Symptoms
    • dorsal wrist pain
      • usually activity related
      • more often in dominant hand
  • Physical exam
    • inspection and palpation
      • +/- wrist swelling
      • often tender over radiocarpal joint
    • range of motion
      • decreased flexion/extension arc
      • decreased grip strength
Imaging
  •  Radiographs
    • recommended views
      • AP, lateral, oblique views of wrist
    • findings (see table above)
  • CT
    • most useful once lunate collapse has already occurred 
    • best for showing
      • extent of necrosis
      • trabecular destruction
      • lunate geometry
  • MRI
    • best for diagnosing early disease 
    • rule out ulnar impaction 
    • findings
      • decreased T1 signal intensity
      • reduced vascularity of lunate
Treatment
  • Nonoperative
    • observation, immobilization, NSAIDS
      • indications
        • initial management for Stage I disease
      • outcomes
        • a majority of these patients will undergo further degeneration and require operative management
  • Operative
    • temporary scaphotrapeziotrapezoidal pinning
      • indications
        • adolescent with radiographic evidence of Kienbock's and progressive wrist pain
    • joint leveling procedure
      • indications
        • Stage I, II, IIIA disease with ulnar negative variance
        • initial operative managment
      • technique
        • can be radial shortening osteotomy or ulnar lengthening
        • more evidence on radial shortening
    • radial wedge osteotomy
      • indications
        • Stage I, II, IIIA disease with ulnar positive or neutral variance
    • vascularized bone grafts
      • indications
        • Stage I, II, IIIA, IIIB disease
      • outcomes
        • early results promising, but long-term data lacking
        • best results in Stage III patients
    • distal radius core decompression
      • indications
        • Stage I, II, IIIA disease
      • technique
        • creates a local vascular healing response
    • partial wrist fusions
      • STT
      • capitate shortening osteotomy +/- capitohamate fusion
      • scaphocapitate
      • indications
        • Stage II disease with ulnar neutral or positive variance
        • Stage IIIA or IIIB disease
        • must address internal collapse pattern (DISI)
    • proximal row carpectomy (PRC)
      • indications
        • stage IIIB disease
        • stage IV disease
      • outcomes
        • some studies have shown superior results of STT fusion over PRC for stage IIIB disease
    • wrist fusion
      • indications
        • stage IV disease
      • technique
        • must remove arthritic part of joint
    • total wrist arthroplasty
      • indications
        • Stage IV disease
      • outcomes
        • long-term results not available
Techniques
  • Vascularized bone grafts
    • technique 
      • many options have been described including
        • transfer of pisiform
        • transfer of distal radius on a vascularized pedicle of pronator quadratus
        • transfers of branches of the first, second, or third dorsal metacarpal arteries
        • 4 + 5 extensor compartment artery (ECA)   
      • temporary pinning of the STT joint, SC joint or external fixation may be used to unload lunate after revascularization
  • Impact of surgical procedure on radiolunate contact stress 
Operative Procedure
% decrease on radiolunate contact stress
STT fusion   3%
Scaphocapitate fusion 12%
Capitohamate fusion 0%
Ulnar lengthening of 4mm 45%
Radial shortening of 4mm 45%
Capitate shortening and capitohamate fusion  66%, but 26% increase in radioscaphoid load

Complications
  • pending
 

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Questions (5)

(OBQ11.112) Figures A through E depict various conditions affecting the pediatric hand and wrist. For which of the depicted conditions is temporary scaphotrapeziotrapezoidal pinning most indicated? Review Topic

QID:3535
FIGURES:
1

A

4%

(85/1895)

2

B

34%

(635/1895)

3

C

4%

(84/1895)

4

D

50%

(950/1895)

5

E

7%

(132/1895)

Select Answer to see Preferred Response

PREFERRED RESPONSE 4

Temporary scaphotrapeziotrapezoidal (STT) pinning is indicated for treatment of Kienbocks disease in adolescents as shown in Figure D. The radiograph shows increased density and slight lunate collapse. The result is a decrease in radiolunate contact stress while increasing the load on the radioscaphoid articulation. STT pinning is not indicated in any of the conditions explained below.

Ando et al retrospectively reviewed the results of six adolescents treated with temporary scaphotrapezoidal (ST) pinning. All patients had an increase in wrist flexion/extension arc, strength, and lunate intensity on MRI from their preoperative baseline.

Shigematsu et al published a case study on a single 11-year-old patient with wrist pain at rest and with use who was treated with temporary scaphotrapeziotrapedoidal (STT) pinning and cast immobilization for 8 weeks. Both wrist ROM and grip strength improved. Lunate revascularization was also seen on subsequent MRI.

Incorrect Answers:
Answer 1,2,3: Radial clubhand, scaphoid fracture, and hypoplastic thumb are not treated with temporary scaphotrapeziotrapezoidal pinning.
Answer 5: Gymnast’s wrist is a distal radius physeal injury due to repetitive axial loading. Plain films will show physeal widening and hazy irregularity. The condition is not treated with temporary scaphotrapeziotrapezoidal pinning.


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Question COMMENTS (3)

(OBQ11.144) A 39-year-old male presents with longstanding right wrist pain. He has failed conservative measures including prolonged immobilization. His radiographs and MRI are seen in figures A and B. Which of the following options is an accepted treatment option? Review Topic

QID:3567
FIGURES:
1

Ulnar shortening osteotomy

5%

(98/1806)

2

TFCC repair

1%

(21/1806)

3

Radius core decompression

79%

(1433/1806)

4

Arthroscopic lunate chondroplasty and debridement

13%

(230/1806)

5

Scapholunate ligament reconstruction

1%

(20/1806)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

The patient in the clinical scenario has Kienbock's disease. Treatment options include a joint leveling procedure, or radius core decompression, which is thought to incite a local vascular healing response in the lunate.

Sherman et al did a biomechanical study reviewing distal radius core decompression for Kienbock's disease. Although the procedure has good clinical outcomes for this disease process, their findings did not show any biomechanical explanation for these good outcomes.

Illarramendi et al reviewed results of curettage of the distal radius and ulna metaphyseal bone through small cortical windows for the treatment of Kienbock's disease. They concluded that the decompression procedure had good results without any complications. Most patients had improvement in pain and were able to return to work.

Incorrect Answers:
Answer 1: Kienbock's disease is commonly associated with ulnar negative variance which is thought to lead to increased forces on the lunate leading to this disease. Therefore a ulnar shortening osteotomy would not be appropriate.
Answer 2,4,5: Are not treatment options for this disease process.


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(OBQ10.61) A 32-year-old carpenter complains of progressively worsening wrist pain for the last 2 months. He denies any recent history of trauma to the wrist or hand. An MRI is obtained and a representative image is provided in Figure A. Which of the following surgical interventions is thought to be effective for this condition by inciting a local vascular healing response? Review Topic

QID:3149
FIGURES:
1

Wrist fusion

0%

(7/1552)

2

Ulnar shortening osteotomy

15%

(232/1552)

3

Distal radius core decompression

79%

(1229/1552)

4

Proximal row carpectomy

2%

(24/1552)

5

Scapholunate ligament reconstruction

4%

(55/1552)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

This clinical scenario and imaging studies are consistent with Kienbock's disease, avascular necrosis of the lunate, in the pre-collapse stage. Core decompression of the distal radius is an accepted treatment for Kienbock's disease. The procedure creates a local vascular healing response facilitating vascular recovery prior to collapse and degeneration of the lunate. Other acceptable interventions include revascularization with a pedicled graft and joint leveling procedures such as a radial shortening osteotomy. The radial shortening osteotomy is ideal for patients with negative ulnar variance who experience greater loads through the radiolunate fossa.

Sherman et al performed a cadaveric study demonstrating minimal change in the distribution of force between the radiocarpal fossa and ulnocarpal fossa following core decompression of the distal radius.

Illarramendi et al reviewed 22 cases of Kienbock's treated with radial and ulnar metaphyseal core decompression. No surgical complications occurred, and 20 of 22 reported satisfactory clinical outcomes while one patient developed intercarpal arthritis.

Incorrect Answers:
1. Proximal row carpectomy and wrist fusion would be options for the collapsed and degenerative lunate.
2. Ulnar shortening osteotomy and scapholunate ligament reconstruction are incorrect as they do not address the pathology of Kienbock's.
4. Proximal row carpectomy and wrist fusion would be options for the collapsed and degenerative lunate.
5. Ulnar shortening osteotomy and scapholunate ligament reconstruction are incorrect as they do not address the pathology of Kienbock's.


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Question COMMENTS (3)

(OBQ10.74) A 30-year-old female undergoes arthroscopy for a chronically painful right wrist that failed to improve with 4 months of immobilization and NSAIDS. Her clinical examination revealed point tenderness dorsally over the lunate but no tenderness elsewhere in the wrist. A picture from the procedure is shown in Figure A where 'R' identifies the distal radius, 'L' the lunate, and '*' represents a chondral flap. The articular surface of the lunate is stable to probing. A radiograph and MRI image of the patients wrist are shown in Figures B and C respectively. What is the most appropriate next step in treatment? Review Topic

QID:3162
FIGURES:
1

Continue Immobilization and NSAIDS

8%

(203/2590)

2

Radial shortening osteotomy

70%

(1814/2590)

3

Proximal row carpectomy

9%

(235/2590)

4

Scaphotrapeziotrapezoid fusion

9%

(244/2590)

5

Wrist fusion

3%

(79/2590)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

The patients clinical presentation and radiographs are consistent with Stage 2 Kienbock's disease in the setting of negative ulnar variance. Radial shortening osteotomy is the most appropriate treatment option listed for Stage 2 disease which is defined as lunate sclerosis without significant collapse. Shortening osteotomy can alter DRUJ contact pressures leading to remodeling, especially in the presence of a Tolat Type II DRUJ, such as that shown in the radiographs. However, this remodeling has been shown to occur without the development of arthritis, and therefore is not a contraindication to this procedure.

This patients radiographs shows some slight sclerosis of the lunate and negative ulnar variance, and the MRI shows diffuse edema and early osteonecrosis of the lunate. The arthroscopic image shows a cartilage flap with a stable base left on the lunate. Based on these images, the patient has Stage 2 disease and should be treated with a joint leveling procedure; or radial shortening osteotomy in this case.

Sltusky et al provide a review article which focuses on the methodology behind a normal arthroscopic wrist examination and discusses some of the more standard arthroscopic procedures along with the expected outcomes.

Bain et al review the arthroscopic staging of Kienbock's disease, and state that this techinique is a valuable assessment tool which allows for not only classification of Kienbock's disease, but also may guide treatment.

Schuind et al. provide a review of the pathogenesis of Kienbock's. They conclude that the natural history of the condition is not well known, and the symptoms do not correlate well with the changes in shape of the lunate and the degree of carpal collapse. They also state that there is no strong evidence to support any particular form of treatment.

Illustration A shows a table which outlines the Stages of Kienbock's Disease.

Illustration B shows a table which outlines the general treatment options for each stage of Kienbock's Disease.

Incorrect Answers:
Answer 1: Immobilization and NSAIDS is indicated in Stage I disease or as a first line of treatment for Stage 2, which this patient has failed.
Answer 3: Proximal row carpectomy is indicated in Stage 3B.
Answer 4: STT Fusion is indicated in Stage 3B.
Answer 5: Wrist fusion is indicated in Stage 4.

ILLUSTRATIONS:

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(OBQ07.244) A 37-year-old man has a 2-year history of increasing right wrist pain that is worse at night and aggravated by activity. He denies systemic symptoms, history of trauma, or recent weight loss. On physical exam he has tenderness over the dorsal radiocarpal joint. Radiographs of the right wrist are shown in Figure A. Which of the following imaging studies would be most sensitive for determining the stage of this patient's underlying condition? Review Topic

QID:905
FIGURES:
1

Ultrasound

1%

(27/2820)

2

Angiography

6%

(183/2820)

3

CT scan of the wrist

65%

(1830/2820)

4

Clenched fist AP radiograph of wrist

8%

(223/2820)

5

Bone scan of the wrist

19%

(546/2820)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

The clinical presentation of dorsal radiocarpal wrist pain is suggestive of Kienbock’s disease. Figure A shows an AP radiograph of the right wrist with evidence of lunate sclerosis with no obvious collapse. The imaging study most sensitive for identifying early lunate collapse in Kienbock's disease is CT scanning of the wrist.

Kienbock’s disease is defined by avascular necrosis of the lunate. It is classified into 4 stages under the Lichtman Classification. In stage 1, plain radiographs appear normal and magnetic resonance imaging is required for diagnosis. MRI is useful for detecting early disease when sclerosis is not evident on plain film radiographs. In stage 2, plain radiographs and/or CT scan images will show sclerosis of the lunate but no evidence of collapse. In stage 3, radiographs and/or CT scan images will show lunate collapse. For stage 4, radiographs show degenerative changes to the adjacent carpus and intercarpal joints.

Imaeda et al. examined the use of MRI for the diagnosis and staging of Kienbock's disease. They found that MRI was most sensitive in detecting early focal loss of signal intensity in the lunate on T1-weighted images. This was a key diagnostic feature in early stages of Kienböck's disease when plain radiographs appear normal.

Cross et al. reviewed the latest concepts for diagnosis, staging, and management of Keinbock's disease. They suggest that computed tomography (CT) or tomography will better characterize lunate necrosis and trabecular destruction once collapse or sclerosis has occurred in late stage disease.

Illustration A is a collection of CT scanning images that show osteonecrosis of the lunate. The blue arrow shows lunate flattening and sclerosis. The red double arrow shows a loss of lunate height and the yellow shows fragmentation of the bone.

Incorrect Answers:
Answer 1: Ultrasound is not used in the staging of Kienbock's disease.
Answer 3: Angiography would not be warranted in this scenario.
Answer 4: A clenched fist AP radiograph of the wrist is used to evaluate widening of the scapholunate interval.
Answer 5: A bone scan of the wrist is a non-specific test, which would likely be positive in almost all patients with chronic wrist pain.

ILLUSTRATIONS:

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