Treatment

The combination of unknown etiology and unknown natural history has led to a large, and sometimes baffling, array of surgical procedures that are difficult to compare.

Because of the many surgical options, the authors will first discuss the different procedures based on their underlying principles in regard to how they attempt to remedy the pathogenesis of the disease. Then we will discuss our approach to treatment of patients who have Kienbock's disease.

Surgical treatment strategies fall into three main categories: biomechanical unloading of the lunate, vascularized bone graft, and salvage. Previous generations of patients were treated with prolonged immobilization [6,29] based on Stahl's early reports that 50% of patients were improved or cured after at least two months in a plaster cast [30]. Casting as a primary treatment for symptomatic Kienbock's disease is no longer considered sufficient [6], but short-term immobilization may lessen synovitis and improve symptoms by reducing loads across the lunate. There may be some cases in which cast treatment alone may be sufficient to ameliorate symptoms and affect the natural history of the disease, but this has not been demonstrated in a controlled study.

Joint-leveling procedures are one way to unload the lunate. These procedures are focused on alteration of the bony anatomy in patients who have negative ulnar variance. They include radial shortening osteotomies and the uncommonly performed ulnar lengthening procedures [31,32]. Ulnar lengthening requires use of structural iliac crest bone graft, necessitating healing of two osteotomy sites rather than one after a shortening procedure. Horii and coworkers [33] used a simplified two-dimensional wrist model to assess the extent of unloading of the radiolunate joint after various osteotomies. They found that shortening the radius or lengthening the ulna by 4 mm resulted in a 45% decrease in radiolunate load, with only moderate changes at the midcarpal and radioscaphoid articulations. This led to radial shortening as primary treatment for Kienbock's disease [28,34]. These studies reported predictable improvements in pain, grip strength, and range of motion. Unfortunately, there was no improvement in the appearance of the lunate on postoperative radiographs.

Radial wedge or dome osteotomies have also been used for the treatment of Kienbock's disease [17,35]. Unlike radial shortening, use of a wedge or a dome osteotomy to reduce the inclination angle of the distal radius can be applied in patients who have ulnar neutral or ulnar positive variance as well as negative ulnar variance [35]. There is evidence that the osteotomy decreases force across the capitolunate and radiolunate joints [20], as well as increases the contact area between the radius and lunate [36]. At a minimum of 10 year follow-up, Koh and colleagues [37] reported that patients maintained their improvements in pain, grip strength, and range of motion. Osteoarthritic changes were seen in 54% of patients at 5 years, and 73% of patients at 10 years, suggesting again that radiologic progression of the disease persisted despite surgical treatment.

Another strategy to unload the lunate is to perform selective carpal fusions. These include capitohamate (CH) fusions, with and without capitate shortening, and scaphotrapeziotrapezoid fusions (STT) or scaphocapitate (SC) fusions. Bio-mechanical studies have suggested that capitoha-mate fusions without shortening do not reduce forces across the radiolunate joint [38,39], although patients do experience decreased pain and improved motion [40]. Capitate shortening with capitohamate fusion has also been described with good clinical results [41]. Biomechanically, Viola and coworkers [42] showed that capitate shortening with capitohamate fusion decreased radiolunate pressure while increasing radioscaphoid pressure, with little effect on mean radiocarpal pressure. The authors have little experience with this technique, and have concerns with possibly causing circulatory compromise in an adjacent carpal bone.

More commonly, STT and SC fusions have been described as a means to successfully reduce load across the lunate by transferring load to the scaphocapitate and radioscaphoid joints [38,39]. Unfortunately, STT arthrodesis also leads to a decrease in wrist range of motion [38]. Several clinical studies have reported decreased pain and increased grip strength on short- and long-term follow-up [43-45], although some of these same studies suggest increased risk of radioscaphoid ar-throsis [44,45].

An interesting development is the use of temporary fixation of joints to help unload the lunate, either with an external fixator or temporary STT or SC pinning [46-48]. Yajima and colleagues [46] felt that the STT fusion was important during lunate revascularization, but unnecessary following remodeling of the lunate. Although this technique has been used in isolation [49,50], it is more commonly used in conjunction with a vascularized bone graft [51,52].

Pedicled vascularized bone grafts (VBG) allow implantation of viable osteoclasts and osteoblasts into the abnormal lunate while preserving the native circulation. This allows for primary bone healing with accelerated creeping substitution and new bone formation. Many different VBGs have been described for the treatment of Kienbock's disease, including use of the pisiform, distal radius, and metacarpals [53-56]. The original description of a vascular pedicle used the second dorsal inter-metacarpal artery and vein implanted into bone [47,57]. The more popular techniques currently allow harvesting of a vascular pedicle with bone graft, and include the 4 + 5 extensor compartmental artery (ECA) and the 2,3 intercompartmental supra-retinacular artery (ICSRA) [51,52,56]. Both of these VBGs have adequate pedicle length for rotation to the lunate, supply cortical and cancellous bone, and can maintain viability of the bone. Moran and coworkers [52] reported improvement of pain, grip strength, and range of motion following 26 cases of 4 + 5 ECA. Furthermore, they that noted 77% of postsurgical patients did not have ra-diologic progression or collapse.

Revascularization with a pedicled bone graft can be used as an adjunct, or an alternative, to any of the unloading-type treatments previously discussed. It is especially attractive in patients who have ulnar neutral or ulnar positive variance, which would preclude consideration of radial shortening procedures. As mentioned, it is typically performed with external fixation or temporary pinning of the STT or SC joints to unload the lunate during revascularization.

Table 2

Options for treatment of Kienbock's disease based on staging

Table 2

Options for treatment of Kienbock's disease based on staging

Kienbock's stage

Treatment options

Stage I

Immobilization

Arthroscopy

Stage II and Ilia

Arthroscopy

Radial shortening osteotomy

(with neutral or negative

ulnar variance)

Vascularized bone graft

Temporary SC or STT pinning

Radial wedge or dome

osteotomy

Capitate shortening, with or

without CH fusion

Combinations of above

treatments

Stage IIIb

STT or SC fusion with or

without lunate excision

Radial shortening osteotomy

Vascularized bone graft

Stage IV

Proximal row carpectomy

Wrist fusion

Wrist arthroplasty

Denervation

Mention should be made of the possibility that these solutions that are based on biomechanical alterations may also have an important biologic effect. For example, osteotomies may work by stimulating a vascular and inflammatory response, and not just by altering radiocarpal loading. Revascularization of an abnormal lunate may be hastened by the act of surgery as well as the postoperative immobilization and therapy.

With lunate collapse (IIIA, IIIB0), some authors have continued to recommend the above procedures, with variable results [34,44,52,58]. More predictably, lunate excision can be performed with SC or STT arthrodesis if the radioscaphoid joint is well-preserved [59]. With degenerative changes throughout the carpus come different considerations for treatment. It is generally agreed that there is no point in revascu-larization or attempting to change the biomechan-ics and load across the lunate. Treatment options are directed toward the pancarpal arthritis, and include proximal row carpectomy, total wrist

Kienbock Disease Stage

Fig. 1. Preoperative Tl-weighted (A) and T2-weighted (B) MRI of a 15-year-old male with Stage I disease and symptoms for over 12 months. (C,D) Repeat MRI 4 months after arthroscopic debridement. There is evidence of revascularization of the lunate. (E) Radiographs 6 months after surgery show no lunate sclerosis. Of note, the patient was ulnar positive, precluding use of a radial shortening procedure.

Fig. 1. Preoperative Tl-weighted (A) and T2-weighted (B) MRI of a 15-year-old male with Stage I disease and symptoms for over 12 months. (C,D) Repeat MRI 4 months after arthroscopic debridement. There is evidence of revascularization of the lunate. (E) Radiographs 6 months after surgery show no lunate sclerosis. Of note, the patient was ulnar positive, precluding use of a radial shortening procedure.

fusion, and wrist denervation. Even with moderate arthritic involvement of the capitate head and the lunate fossa, a proximal row carpectomy can provide a successful outcome with interposition of dorsal capsule or other material [60,61]. It also helps to preserve an already reduced range of motion, and allows for the possible conversion to total wrist fusion or even a total wrist artho-plasty at a later date. Wrist denervation procedures, although attractive in theory, have not yielded better results than wrist fusion or proximal row carpectomy [62-64]. Of course, wrist de-nervation can be combined with any of the other procedures to add a measure of symptom-relief in terms of pain control.

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Responses

  • mebrahtu
    How to treat kienbock disease?
    6 years ago
  • mike
    How successful is radial shortening for keinbock disease?
    10 months ago
  • Katri
    Does bone graft revascularization work in keinbocks iiib?
    9 months ago

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