Nilesh M. Chaudhari, Mohamed Khalid, and Thomas R. Hunt III
DEFINITION
Lunate revascularization for Kienböck disease involves transfer of either a vessel or a pedicled bone graft to the lunate in an attempt to reverse avascular necrosis.
Vascularized bone grafts from the pisiform, volar and dorsal radius metaphysis, second metacarpal head,6 and iliac crest (via free microvascular graft)2 have all been reported.
Unloading procedures, like a capitate shortening osteotomy, are often combined with a revascularization procedure to protect the graft and to alter forces through the lunate.
ANATOMY
Vascular Anatomy of the Dorsal Distal Radius
The dorsal distal radius is primarily supplied by the branches of the radial artery and the posterior division of the anterior interosseous artery (pAIA) (FIG 1).
The 2, 3 intercompartmental, supraretinacular artery (2, 3 ICSRA) is superficial to the extensor retinaculum and passes between the second and third extensor compartments (Fig 1).
The fourth extensor compartment artery (ECA) is located deep to the extensor retinaculum in the fourth extensor compartment (Fig 1).
It lies directly adjacent to the posterior interosseous nerve on the radial floor of that compartment.
It originates from the pAIA or the fifth ECA.
It anastomoses with the dorsal intercarpal arch and the dorsal radiocarpal arch.
The fourth ECA is a source of numerous small nutrient arteries to the dorsal radius at the level of the fourth extensor compartment that penetrate deeply into cancellous bone.
The fifth ECA is located deep to the extensor retinaculum in the fifth extensor compartment or within the septum between the fourth and fifth extensor compartments (Fig 1).
It is the largest of the four dorsal vessels.
It originates from the pAIA and anastomoses distally with the fourth ECA, the dorsal intercarpal arch, the radiocarpal arch, the 2, 3 ICSRA, and/or the oblique dorsal artery of the distal ulna.
The fourth and fifth ECA pedicle is ideal for use in grafting the lunate because of the large diameter of the fifth ECA, the length of combined pedicle, the ulnar location of the fifth ECA (away from necessary incisions), and the multiple anastomoses, which provide retrograde flow.
The fifth ECA by itself seldom provides direct nutrient branches to the radius.
A 2, 3 ICSRA graft based on antegrade flow through the fifth ECA can be used if the fourth ECA is damaged or not present.
Vascular Anatomy of the Dorsal Hand
The blood supply to the hand consists of a series of anastomotic arches over the carpus that form the dorsal carpal arch, usually with contributions from both the radial and ulnar arteries (Fig 1).3,8
The dorsal carpal arch lies distal and deep to the extensor retinaculum.
The dorsal metacarpal arteries lie just deep to the fascia overlying the interossei muscles.
The second, third, and fourth dorsal metacarpal arteries arise from the dorsal carpal arch. They terminate by dividing into digital arteries.
FIG 1 • Arterial anatomy of the dorsal distal radius and wrist. RA, radial artery; UA, ulnar artery; AIA, anterior interosseous artery; pAIA, posterior division of anterior interosseous artery; 4th ECA, fourth extensor compartment artery; 5th ECA, fifth extensor compartment artery; 2, 3 ICSRA, 2, 3 intercompartmental supraretinacular artery.
FIG 2 • A. At the time of surgery the articular surfaces are carefully evaluated. B. T2-weighted MRI sagittal image of the lunate revealing a coronal plane fracture line, separation of volar and dorsal fragments, and interruption in the cartilaginous envelope. (Copyright Thomas R. Hunt, III, MD.)
The digital arteries are also supplied by perforating branches from the deep palmar arch.
The first and fifth dorsal metacarpal arteries are direct branches from the radial and ulnar arteries respectively.
The second dorsal metacarpal artery is the preferred vascular source for vessel implantation due to its size and predictable presence.
If this vessel is damaged or cannot be found, the third dorsal metacarpal artery may be used.
SURGICAL MANAGEMENT
Treatment of Kienböck disease is based on the following factors:
Lichtman stage
Ulna variance
Presence of arthritic changes
Integrity of the lunate's cartilaginous shell (FIG 2)
Patient symptoms and other patient-specific factors
Nonsmokers with Stage I to IIIA Kienböck disease, an intact lunate cartilaginous shell (as determined using sagittal images and at surgery), and limited arthritic changes are suitable candidates for treatment using a vascularized grafting procedure (FIG 3).
Relative contraindications to vascularized grafting include:
Previous surgery with exposure of the dorsal aspect of the hand and wrist
Age more than 60 years
History of peripheral vascular diseases or poorly controlled diabetes
Vascular grafting is accompanied by a lunate unloading procedure.
Unloading has been shown to improve symptoms related to Kienböck disease (see Chap. HA-23).
Altering force distribution through the lunate serves to protect the vascular grafts and to encourage revascularization.
FIG 3 • A, B. AP and lateral radiographs showing stage II–III Kienböck disease with sclerosis and subtle, early collapse. There is no evidence of a coronal plane fracture line. C. T1-weighted MRI coronal image showing loss of marrow signal of the lunate. (Copyright Thomas R. Hunt, III, MD.)
Unloading procedures commonly used in conjunction with a vascular procedure include:
Capitate shortening osteotomy is our preferred choice in patients with positive or neutral ulna variance. This procedure is completed before inserting the vascular graft or vessel.
Scaphocapitate pinning or external fixation (4 to 6 weeks) is used when ulna variance is positive and a contraindication to capitate shortening osteotomy exists.
Radius shortening and angular osteotomy is used when ulna variance is negative (see Chap. HA-23).
Intercarpal arthrodesis (see Chap. HA-88).
Preoperative Planning
The surgeon should review all imaging studies to determine the stage of the disease, ulna variance, and the status of the lunate's articular shell.
Positioning
The patient is positioned supine with the arm on a radiolucent armboard.
A proximal arm tourniquet is applied. Gravity exsanguination of the limb before tourniquet inflation allows visualization of the vessels.
Approach
The surgeon should consider arthroscopic assessment before the open approach if the status of the lunate articular shell is in question.
The 4-5 portal and ulnar midcarpal portal should be avoided as they may damage 4+5 ECA.
Dorsal approaches to the hand and the wrist are used.
Specific incision placement varies based on the graft choice and associated lunate unloading procedure.
TECHNIQUS
VASCULARIZED BONE GRAFTING
Exposure and Identification of the Fourth and Fifth Extensor Compartment Arteries
Make a 5- to 6-cm longitudinal skin incision between fourth and fifth extensor compartments, ending distally between the third and fourth metacarpal bases.
Incise the fifth extensor compartment.
Identify the fifth ECA and its venae comitantes on the radial aspect of the compartment lying adjacent to or partially within the septum and separating the fourth and fifth extensor compartments (TECH FIG 1).
Trace the fifth ECA proximally to its origin from the posterior division of the anterior interosseous artery as it emerges from the interosseous membrane.
Identify the fourth ECA arising from the same feeding vessel.
Trace the fourth ECA distally and identify the area of greatest vascular penetration into bone, typically 1 cm proximal to the radiocarpal joint.
Lunate Preparation
Elevate the extensor retinaculum as a radial-based flap from the fifth through the second extensor compartments to allow joint capsulotomy.
Carefully protect the dorsal carpal arch.
TECH FIG 1 • A. The fifth extensor compartment artery is identified and carefully traced proximally to its origin from the posterior division of the anterior interosseous artery. B. Matching clinical photograph showing fourth and fifth extensor compartment arteries. (B: Copyright Thomas R. Hunt, III, MD.)
Perform a ligament-splitting capsulotomy and protect the scapholunate and lunotriquetral ligaments.
Inspect the lunate, its cartilage shell, and surrounding articular surfaces.
Consider vascularized bone grafting only if the shell is not compromised, the bone is not fragmented, and the joint is not arthritic.
Enter the noncartilaginous portion of the dorsal lunate cortex using a small curette or a 2- to 3-mm round burr.
Through this dorsal cortical window and under direct visualization and fluoroscopic guidance, carefully remove necrotic bone from the lunate by hand with curved and straight curettes.
Leave a shell of intact subchondral bone.
If the lunate is collapsed, expand it gently using a small blunt-ended lamina spreader.
The amount of expansion obtained is highly variable.
Use of a lamina spreader in this manner is not suggested in cases with bone fragmentation.
Determine the graft size required by measuring the dorsal excavated area of the lunate.
Sharply elevate the vascular pedicle from the bone while protecting the nutrient vessels at the graft site.
Complete elevation of the corticocancellous graft using sharp osteotomes, with judicious handling of the vascularized pedicle (Tech Fig 2).
Deflate the tourniquet to verify blood flow to the graft.
Protect the pedicle graft in a moist sponge.
Placement of the Vascularized Bone Graft into the Lunate
Obtain cancellous bone graft from the donor site in the distal radius and pack this graft into the lunate cavity using fluoroscopic images for guidance.
Using small, precise rongeurs, contour the corticocancellous pedicle graft to the size needed.
Insert the vascularized bone graft with the cortical surface arranged in a proximal–distal orientation and without tension on the vascular leash (TECH FIG 3).
This allows the graft to serve as a strut to help maintain lunate height during revascularization.
No internal fixation is necessary to secure the graft in the lunate.
Elevation of the Vascularized Bone Graft
Using a smooth 0.045-inch Kirschner wire, outline the area of the distal radius most infiltrated by nutrient vessels from the fourth ECA.
The size of the graft is influenced by the nutrient vessels and the earlier measurement.
Ligate the posterior division of the anterior interosseous artery proximal to the fourth and fifth ECA branches (TECH FIG 2).
Closure
Repair the capsule using absorbable suture, taking great care to avoid pressure on the vascular pedicle.
Close the extensor retinaculum with absorbable suture and the skin with Prolene.
Apply a nonocclusive dressing and a volar, below-elbow splint.
TECH FIG 2 • A, B. Drawing and clinical picture after ligation of the posterior division of anterior interosseous artery (pAIA) and harvest of the corticocancellous bone graft. (B: Copyright Thomas R. Hunt, III, MD.)
TECH FIG 3 • A, B. Drawing and corresponding clinical picture showing inset of the vascularized bone graft into the prepared lunate. Note the proximal–distal orientation of the cortex. (B: Copyright Thomas R. Hunt, III, MD.)
VASCULAR BUNDLE IMPLANTATION
Incision and Approach
Make an extensive dorsoradial incision extending from the second metacarpophalangeal joint to a point about 4 cm proximal to the wrist, which gently slopes ulnarly around the tubercle of Lister.
Visualize and protect the dorsal sensory branch of the radial nerve.
Incise the extensor retinaculum over the third compartment and transpose the extensor pollicis longus into a subcutaneous position.
Retract the contents of the fourth extensor compartment ulnarly and the second extensor compartment radially.
Use fluoroscopy to confirm the lunate's location.
Perform a standard ligament-splitting capsulotomy.
Take care to avoid injury to the transverse basal dorsal metacarpal arch from which the vascular pedicle arises.
Inspect the lunate and surrounding joints. Perform a synovectomy as required.
Elevation of the Second Dorsal Metacarpal Vascular Pedicle
In the interval between the second and third metacarpals, incise the interosseous muscle fascia from proximal to distal.
The vessels lie underneath the aponeurosis that covers the interosseous muscles.
Elevate the artery and venae comitantes along with a thin layer of surrounding perivascular areolar tissue from the second dorsal web space to the dorsal carpal arch (TECH FIG 4A).
Identify and coagulate all branches off this main metacarpal artery.
Ligate the vessel at its most distal location.
This should provide a 5- to 6-cm vessel of adequate length to reach the dorsal lunate.
Lunate Preparation and Implantation of the Vascular Bundle
Curette and expand the lunate as discussed earlier.
Pack autogenous cancellous bone graft into the lunate.
Use a 2.7-mm bit and drill from dorsal to volar through the body of the lunate.
Sew a 5-0 monofilament suture to the end of the mobilized vessel, then place the suture ends through the eye of a straight needle.
Feed the vessel into the avascular portion of the lunate by passing the needle from dorsal to volar through the previously drilled hole, exiting the palmar skin just ulnar to the flexor carpi radialis tendon (TECH FIG 4B).
Make a small skin incision over the needle and tie the suture over the palmar antebrachial fascia.
Release the tourniquet to assess vessel patency.
Achieve hemostasis and close the capsule, retinaculum, and skin in the manner described earlier.
Apply a nonocclusive dressing and a volar, below-elbow splint.
TECH FIG 4 • A. The artery has been ligated distally and mobilized proximally along with its perivascular tissue. B. Fine suture is sewn to the edge of the vessel lumen and placed into a straight Keith needle for insertion into the lunate from a dorsal to volar direction.
CAPITATE SHORTENING OSTEOTOMY
Capitate Osteotomy
After the capsular-sparing incision is performed for the vascular procedure but before the graft or vessel is inset into the lunate, identify the waist of the capitate and confirm the osteotomy site with fluoroscopic imaging.
The osteotomy should correspond to the level of the scaphotrapeziotrapezoidal joints (TECH FIG 5A).
Use a sharp osteotome, a fine water-cooled saw, or both to resect a 2.0-mm wafer bone from the capitate (TECH FIG 5B).
Complete the proximal cut before the distal cut.
Perform a trial reduction using a Freer elevator in the midcarpal joint to control and compress the proximal capitate fragment.
If this trial reduction reveals that the proximal hamate is prominent in the midcarpal joint or the hamate–lunate articulation is incongruous, perform a hamate osteotomy in the same manner and at the same level as the capitate osteotomy.
Osteotomy Fixation
Compress the two cut surfaces of the capitate manually as discussed earlier in preparation for placement of a cannulated, headless compression screw.
Place the guidewire across the osteotomy site of the capitate from proximal to distal.
Wrist flexion helps present the capitate head into the field. Be careful to avoid distraction of the osteotomy with this maneuver.
TECH FIG 5 • A. The capitate osteotomy is performed at the waist, which corresponds to the level of the scaphotrapeziotrapezoidal joints. B. A 2-mm wafer of bone is removed from the capitate. The proximal cut is completed first. The cuts must be parallel to ensure precise reduction. (Copyright Thomas R. Hunt, III, MD.)
Confirm the placement of the guidewire with fluoroscopy.
Insert the headless compression screw over the guidewire and achieve compression across the osteotomy site (TECH FIG 6A).
Complete the vascular procedure as indicated and close the wrist capsule, the extensor retinaculum, and the skin (TECH FIG 6B).
Apply a bulky hand dressing with a volar splint.
TECH FIG 6 • A. A headless compression screw is inserted antegrade. Wrist flexion provides access to the capitate head. B. Posteroanterior radiograph after vascularized bone grafting and capitate shortening osteotomy. (Copyright Thomas R. Hunt, III, MD.)
POSTOPERATIVE CARE
Remove the dressing 10 to 14 days postoperatively and apply a below-elbow cast for 3 weeks.
Remove the cast 4 to 5 weeks after surgery and initiate supervised therapy emphasizing active wrist motion. Over the next 4 weeks the patient can progress to active assisted and then passive range-of-motion exercises.
A removable splint is used for 3 to 4 weeks.
Evaluate the progress of healing using serial radiographs.
Strengthening is initiated at 3 months after surgery and slowly progressed.
Patients undergoing revascularization of the lunate are followed for 1 to 3 years.
OUTCOMES
Lunate revascularization techniques have demonstrated promising clinical results for Kienböck disease.1,7
Mazur et al4 described the results of nine reverse-flow pedicle grafts obtained from the radius metaphysis in patients with stage IIIA Kienböck disease.
Grip strength was improved by 25%, ultimately measuring 60% to 100% of the opposite side.
Range of motion of the wrist joint was not significantly different from the preoperative status.
Radiographic measurements demonstrated no change in the modified carpal height ratio, lunate index, or scapholunate angle.
MRI data demonstrated progressive signs of revascularization over time. Normalization of T2 values was seen initially by 18 months, followed by normalization of T1 values by 36 months.
Moran et al5 retrospectively reviewed the results of 24 patients treated with vascularized bone graft using 4+5 extensor compartment artery (4+5 ECA).
Grip strength improved from 50% to 89% of the unaffected side.
Ninety-two percent of the patients had significant improvement in their pain.
Seventy-seven percent of patients showed no further collapse on postsurgical radiographs.
Seventy-one percent of the patients showed evidence of revascularization with improvement in the T2 signal, T1 signal, or both.
Waitayawinyu et al9 described the results of 14 patients who had capitate shortening osteotomy with vascularized bone grafting for Kienböck disease; all had positive ulna variance.
Grip strength was improved from 58% to 78% of the normal side.
Average time to osteotomy healing was 48 days.
COMPLICATIONS
Failure of revascularization of the lunate or progression of disease may necessitate a second procedure such as intercarpal arthrodesis, proximal row carpectomy, total wrist arthrodesis, or wrist denervation.
Continued inflammation or disease progression may cause persistent pain, which may require brief periods of splinting during symptomatic flares.
REFERENCES
1. Bouchud RC, Buchler U. Kienböck's disease, early stage 3-height reconstruction and core revascularization of the lunate. J Hand Surg Br 1994;19B:466–478.
2. Galb M, Reinhart C, Lutz M, et al. Vascularized bone graft from the iliac crest for the treatment of nonunion of the proximal part of the scaphoid with an avascular fragment. J Bone Joint Surg Am 1999; 81A:1414–1428.
3. Hori Y, Tamai S, Okuda H, et al. Blood vessel transplantation to bone. J Hand Surg Am 1979;4A:23–33.
4. Mazur KU, Bishop AT, Berger RA. Vascularized bone grafting for Kienböck's disease: method and results of retrograde-flow metaphyseal grafts. American Society for Surgery of the Hand 51st Annual Meeting, Nashville, TN, 1996.
5. Moran SL, Cooney WP, Berger RA, et al. The use of the 4+5 extensor compartmental vascularized bone graft for the treatment of Kienböck's disease. J Hand Surg Am 2005;30A:50–58.
6. Sheetz KK, Bishop AT, Berger RA. The arterial blood supply of the distal radius and ulna and its potential use in vascularized pedicle bone grafts. J Hand Surg Am 1995;20A:902–914.
7. Shin AY, Bishop AT. Vascularized bone grafts for scaphoid nonunions and Kienböck's disease. Orthop Clin North Am 2001;32: 263–277.
8. Tamai H, Yajima H, Mizumoto S, et al. Treament of Kienböck's disease with vascular bundle implantation. Transaction of the American Society of Surgery of the Hand 1980;3:69.
9. Waitayawinyu T, Chin SH, Luria S, et al. Capitate shortening osteotomy with vascularized bone grafting for the treatment of Kienböck's disease in the ulnar positive wrist. J Hand Surg Am 2008;33A:1267–1273.