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Kienbock Disease Australia Support & Information Group
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Kienbocks Disease may be treated by immobilization, revascularization, ulnar lengthening or radial shortening, simple excision, limited intercarpul fusion, or salvage procedures.
Immobilization
Prolonged immobilization of the wrist has been tried in all stages of Kienbock's disease. In some cases it has shown to lead to continued collapse of the lunate. For Stage I, however, immobilization may be indicated in hopes that the vascular insult is kept to a minimum and that the lunate is given a chance to heal. Because diagnosis in this stage is often difficult, a trial period of immobilization may result in characteristic radiographic changes that establish the diagnosis.
Revascularization
In stage II Kienbock's Disease, before the lunate has collapsed, it is possible for the lunate to regain blood supply.
One procedure is which a small piece of volar radial bone, still attached to the pronator quadratus muscle, is grafted to the avascular lunate. This procedure is done through the volar approach with division of the palmer and transverse carpul ligaments in order to mobilize the median nerve. After the volar wrist is entered the lunate is burred with a high speed drill in preparation to receive a 1 to 1.5 cm piece of radial bone still attached to the pronator quadratus muscle. This is secured with pull out wires or clips.
A similar revascularization procedure uses the pisiform. Pisiform transfer on its vascular pedicle. Has found uniformly good results
Another is described as direct transplanting of a vascular bundle into the vascular lunate, with successful results.
It must be remembered, however, that none of the revascularization procedures are likely to work in the face of severe collapse (stage III), for even if they are successful in re-establishing blood supply, lunate height and normal carpul kinematics will not be restored.
Ulna Lengthening and Radial Shortening
On the basis of the theory that ulnar minus variance is a significant etiologic factor in Kienbock's Disease, some have advocated equalization of the distal articular surfaces by either ulnar lengthening or radial shortening. Both procedures have had good results reported. However, it seems unlikely that leveling of the distal articular surfaces of the lunate can restore an already collapsed lunate. These procedures remain questionable in advanced stage III.
Both radial shortening and ulnar lengthening require osteotomy. A segment of bone is removed when radial shortening is done and a segment of bone graft inserted when ulnar lengthening is done. After either, fixation is usually accomplished with a compression plate. It is generally recommended that the ulnar variance be changed to 1 to 2 ml positive variance by placing an appropriate sized interpositional graft during ulnar lengthening.
Radial shortening may be preferable to some because it does not require a second surgical incision to harvest bone graft.
Excision of the Lunate
Lunate excision was one of the first surgical procedures for Kienbock's Disease. The rational of this procedure is to remove sequested bone that is provoking painful synovitis. Some have reported good results from simple excision others critize the procedure predicting late proximal migration of the capitate.
Limited Intercarpul fusion
Its most important advantage is that radiocarpul motion is maintained, unlike with complete wrist arthrodesis.
Patients with severe fragmentation of the lunate undergo resection of the necrotic bone, osteotomy of the capitate in its mid portion, and proximal displacement of the proximal capitate fragment, which is secured to the scaphoid and triquetrum with bone pegs. Essentially, the space vacated by excision of the lunate is filled by the proximal half of the capitate fragment, and the space left by osteotomy of the capitate is filled by autogenus bone graft. The procedure is then completed by performing arthrodesis of contiguous surfaces of the hamate, capitate, scaphoid and triquetrum by first denuding articular surfaces and securing the bone with small cortical bone pegs. When the lunate remains suitably intact, osteotomy of the capitate is omitted, as is lunate excision, and the contiguous surface of the lunate, scaphoid, triquetrum, hamate and capitate are arthrodesed.
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