You are in: eMedicine Specialties > Orthopedic Surgery > HAND AND UPPER EXTREMITY Kienböck DiseaseArticle Last Updated: Jul 11, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: Brian J Divelbiss, MD, Consulting Staff, Dickson-Diveley Midwest Orthopaedic Clinic, Inc, Kansas City Orthopaedic Institute Brian J Divelbiss is a member of the following medical societies: Alpha Omega Alpha and American Society for Surgery of the Hand Coauthor(s): Mark E Baratz, MD, Professor, Department of Orthopaedics, Drexel University College of Medicine; Residency Director, Department of Orthopaedics, Allegheny General Hospital; Consulting Staff, Allegheny Orthopaedic Associates Editors: A Lee Osterman, MD, Director of Hand Surgery Fellowship, Director, Philadelphia Hand Center; Director, Professor, Department of Orthopedic Surgery, Division of Hand Surgery, University Hospital, Thomas Jefferson University; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; N Ake Nystrom, MD, PhD, Associate Professor of Orthopedic Surgery and Plastic Surgery, University of Nebraska Medical Center; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Harris Gellman, MD, Consulting Surgeon, Broward Hand Center, Voluntary Clinical Professor of Orthopedic Surgery and Plastic Surgery, Departments of Orthopedic Surgery and Surgery, University of Miami School of Medicine Author and Editor Disclosure Synonyms and related keywords: avascular necrosis of the lunate, osteonecrosis of the carpal lunate, wrist injury, wrist pain, lunatomalacia, Kienbock disease, triangular fibrocartilage complex, TFCC, ulnar, ulnar variance, negative ulnar variance, positive ulnar variance, radial shortening, ulnar lengthening, lunate collapse, scaphoid rotation, lunate excision, scaphotrapeziotrapezoid, triscaphe, STT, STT fusion, STT arthrodesis, scaphocapitate, capitohamate, carpectomy, proximal row carpectomy, PRC, ulnar-negative variance, ulnar-positive variance INTRODUCTIONSection 2 of 9
  Kienböck disease is a condition of uncertain etiology that results in osteonecrosis of the carpal lunate. History of the ProcedureIn 1843, Peste presented the initial description of lunate collapse in the French literature. Nearly 70 years later, a Viennese radiologist named Robert Kienböck introduced the term "lunatomalacia" to describe the condition that bears his name. Kienböck believed that traumatic rupture of the ligaments and vessels around the lunate produced lunate fracture with subsequent collapse. In 1928, Hulten noted an association between Kienböck disease and the presence of negative ulnar variance. He advanced the progress of treatment by advocating shortening of the radius. Shortly thereafter, Persson presented the option of lengthening the ulna to restore normal ulnar variance. ProblemThe true natural history of this condition is not well understood, and this has hampered the determination of the ideal treatment. As with many conditions that affect the wrist, the clinical condition of the patient does not necessarily correlate well with the radiographic appearance. FrequencyKienböck disease usually affects the dominant wrist of men aged 20-40 years. EtiologyAlthough the underlying etiology is not known, the final results of fragmentation and collapse are secondary to osteonecrosis. Intrinsic and extrinsic factors have been implicated. Intrinsic factorsVascular supply The vascular supply of the lunate has been well studied by Gelberman.1, 2 It consists of both extraosseous and intraosseous vessels running in the dorsal and volar radiocarpal ligaments. Three vessel patterns of intraosseous supply have been noted. In 70% of lunates, multiple vessels enter either volarly or dorsally (X or Y pattern). In the remaining 30% (I pattern), only a single vessel is present palmarly and dorsally, which theoretically places these lunates at increased risk of losing vascular supply. Kienböck disease has not been reported following perilunate dislocations where the vascular supply has been damaged completely. Early signs of osteonecrosis (eg, increased radiodensity on plain radiographs) may be seen but have not been followed by progression to collapse. Increased intraosseous pressure has been shown to occur in lunates with Kienböck disease, but it is unclear whether this is a primary or secondary finding. Lunate and distal radius geometry Zapico has classified lunate geometry into 3 types: Type I lunates occur in ulnar-negative wrists, while type II and III lunates are seen in ulnar-neutral or ulnar-positive wrists. His thesis was that the weakest trabecular pattern was seen in the type I lunate, thereby helping to explain the relationship between the ulnar-minus variant and the disease. Later work by Tsuge, however, failed to show an association between lunate geometry and Kienböck disease. Mirabello demonstrated that patients with Kienböck disease with decreased radial inclination developed the disease at an earlier age. The exact biomechanical effect of de novo decreased radial inclination has not been determined. Extrinsic factorsRelationship between the radii of curvature of the lunate and capitate Compressive axial forces are concentrated on the distal articular surface of the lunate because the radius of curvature of the capitate is less than that of its articulating surface on the lunate. As the capitate settles proximally later in the disease process, it can act as a wedge to split the lunate into dorsal and volar halves. Repetitive trauma While no specific data support a causal relationship, a history of repetitive microtrauma is often noted in patients with Kienböck disease. Ulnar variance While not thought to be causal, a statistical relationship between negative ulnar variance and Kienböck disease appears evident. In Hulten's original work, he noted that 23% of the general population has negative ulnar variance, while 74% of his patients with the disorder were ulnar minus. The ulnar-minus variant has been shown experimentally to cause an abnormal increase in the force transmitted across the lunate. In addition, the triangular fibrocartilage complex (TFCC) is thicker in these patients, and the differential loading between it and the ulnar edge of the radius is increased. De Smet, however, counters that true correlation between the ulnar-minus variant and Kienböck disease has not been proven when appropriate sex- and age-matched controls and radiographs have been used.3 The etiology of Kienböck disease has not been clearly determined. Most likely, it occurs as a result of repeated loads to a "lunate at risk" by virtue of its unique vascular or mechanical environment. PathophysiologyForce transmission studies have formed an important part of the understanding of the pathophysiology of Kienböck disease. In the normal wrist in neutral alignment, 80% of the axial load through the wrist is transmitted through the radiocarpal joint, while the remaining 20% goes through the ulnocarpal joint. Two-dimensional theoretical models of force transmission in patients with Kienböck disease have demonstrated that in the early stages of the disease (II and IIIa), the normally positioned scaphoid prevents excessive forces on the lunate. However, as the scaphoid assumes its flexed position in stage IIIB, loads across the lunate are increased. These excessive loads may further accelerate the process of fracture and fragmentation leading to collapse. ClinicalThe most common patient with Kienböck disease is a man aged 20-40 years who is either a manual laborer or one who participates in recreational activities that repetitively load the wrist. Patients present with reports of activity-related dorsal wrist pain, decreased wrist motion in the flexion-extension arc, and poor grip strength. The symptoms tend to occur more often in the dominant hand. Dorsal wrist swelling and tenderness are frequently present over the radiocarpal joint. A history of trauma is variable and may be in the distant past. A recent review that focused on Kienböck disease in women revealed that men and women have different presentations of Kienböck disease. Women had roughly equivalent involvement of the dominant and nondominant sides, and they tended to present at a much older age (46 years versus 31 years for men). INDICATIONSSection 3 of 9
The primary indication for operative treatment in Kienböck disease is persistent pain not responsive to conservative treatment such as nonsteroidal anti-inflammatory drugs (NSAIDs) and immobilization. Most patients with Kienböck disease who have moderate-to-severe symptoms are candidates for operative intervention. The choice of operative technique is based on patient age, stage of disease, and the presence or absence of ulnar variance. RELEVANT ANATOMYSection 4 of 9
See Surgical therapy. CONTRAINDICATIONSSection 5 of 9
The primary contraindication to consider in the operative treatment of Kienböck disease is ulnar-positive or ulnar-neutral variance because in patients with such variance, joint-leveling procedures (radial shortening and ulnar lengthening) cannot be performed. WORKUPSection 6 of 9
Imaging Studies
TREATMENTSection 7 of 9
Medical therapyThe primary methods of nonoperative treatment are immobilization and anti-inflammatory medications. As noted previously, the natural history of Kienböck disease is not well determined. Therefore, treatment is primarily directed by the level of symptoms. Certainly, a very young patient, although an unusual presentation of Kienböck disease, should be given an adequate trial of immobilization in hopes of allowing revascularization of the lunate and preventing disease progression. Surgical therapyA number of options are available for surgical management of Kienböck disease. The 2 most important pieces of information are the stage of the disease and the presence or absence of ulnar variance. Directly comparing the results of different techniques is difficult because most studies have a fairly small number of patients and short follow-up. However, review of the literature reveals that many of the techniques result in very similar rates of good outcomes. Operative treatment can be classified broadly into 6 categories, as follows:
Lunate excision with or without replacement
Joint-leveling procedures Radial shortening and ulnar lengthening are the 2 options to level the joint. The goal is to produce a wrist with neutral ulnar variance, although correction should probably not exceed 4 mm, because nearly all strain reduction occurs in the first 2 mm of correction. Strains at the lunate can be reduced by 70% with an appropriate radial shortening or ulnar lengthening. Currently, radial shortening with a volar distal radius locking plate is preferred over ulnar lengthening because there is a lower complication rate with the volar-shortening procedure and because the 2 procedures have shown similarly good outcomes. In patients with neutral or positive ulnar variance, shortening the radius is contraindicated. In this clinical situation, radial wedge osteotomies designed to decrease the radial inclination have been proposed. Intercarpal fusions Various intercarpal fusions for the treatment of Kienböck disease have been reported. The goal is to reduce lunate strain and, in procedures that involve the scaphoid, to correct and maintain proper scaphoid position. Of the limited intercarpal fusions reported, the greatest experience has been with scaphotrapeziotrapezoid (STT) (triscaphe) fusion. STT arthrodesis does decrease lunate strain but by merely shifting it to the radioscaphoid joint. STT fusion in a cadaver model was found to provide strain reduction similar to that of joint-leveling procedures but with greater loss of motion. The use of STT fusion has waned in recent years because of complications and longer-term follow-up that has revealed decreased success rates. Several authors have reported scaphocapitate (SC) fusion. Biomechanically, this fusion has been shown to reduce strain at the radiolunate joint by about 10%. Some authors prefer this fusion because it requires only one fusion site and is technically easier to perform. Finally, capitohamate fusion has been reported in a study with a short follow-up. However, this fusion alone has been shown to be biomechanically ineffective in reducing lunate strain. If this fusion is combined with capitate shortening, significant reductions of load across the radiolunate and SC joints have been noted. This load reduction is offset by large force increases at the ulnotriquetral, triquetrohamate, and scaphotrapezial joints. This method also does not address the scaphoid rotation that occurs with stage IIIb disease. At the present time, intercarpal fusions are more likely to be reserved for patients with neutral or positive ulnar variance in whom a joint-leveling procedure is contraindicated. Revascularization In the late 1970s, Hori presented his initial work on the use of a vascular pedicle directly implanted into the lunate. Nearly all of his patients showed improvement in their pain at later follow-up. Currently, most revascularizations use vascularized bone pedicles. There are several sources for the pedicles, including the distal radius,4 pisiform,5 and pronator quadratus (Braun). Results with the use of pedicled distal radius grafts have shown improved grip strengths and progressive MRI evidence of revascularization over an 18- to 36-month period.6 Revascularization techniques may also be combined with other previously mentioned approaches. Revascularization is especially attractive for the young patient with ulnar-neutral or -positive variance in whom a radial shortening is not an option and in a patient who wishes to avoid an intercarpal fusion and resultant loss of motion. Salvage procedures Salvage procedures are reserved for later stages of disease and for failures of other treatments. Proximal row carpectomy (PRC) has been shown to provide relatively good results for Kienböck disease, as well as for other wrist problems. Wrist arthrodesis is the final option for patients with global wrist degeneration. Arthrodesis can be achieved successfully following a failed PRC. Other procedures Possible other procedures include the following:
A reasonable approach to determining the surgical treatment of Kienböck disease based on stage is as follows:
OUTCOME AND PROGNOSISSection 8 of 9
The natural history has not been well elucidated, primarily because few reported series focus exclusively on nonoperative treatment. Kristensen monitored 49 patients nonoperatively for an average of 20.5 years and found that 80% of the patients had no pain or had pain only with heavy labor.7 Most patients reported a gradual lessening of symptoms over time. This benign clinical picture was not mirrored by radiographic findings, as degenerative changes in the wrist were common and every lunate was deformed. Mikkelsen noted that 15 of 25 patients treated conservatively had daily problems with the wrist.9 He concluded that nonoperative treatment was not indicated for Kienböck disease. In the early stages of Kienböck disease, a short trial of casting may alleviate symptoms and obviate the need for surgery. These patients should be monitored closely so that surgery, if necessary, can be performed when radial shortening is still feasible. Although initial success was seen with the use of a silicone spacer following lunate resection, this implant is no longer indicated. Alexander presented a 5-year follow-up of a group of 10 patients with silicone lunate replacements and noted 50% unsatisfactory results.10 Sixty percent of patients who had radiographs at final follow-up demonstrated evidence of silicone particulate synovitis. Lunate excision is not commonly recommended because of concerns of progression of carpal collapse. A fascial or palmaris anchovy replacement has had variable success in preventing subsequent collapse, although Carroll reported long-term (>10 y) success in a series of 10 patients treated with a fascial implant following lunate excision. He noted no evidence of carpal collapse, and all patients had unrestricted use of their hands. Radial shortening remains a mainstay of treatment. It is a reliable, reproducible procedure with good results. Weiss and Quenzer have presented large series of radial shortenings.11, 12, 13 They have noted decreased pain in about 90% of patients, as well as improved motion and grip strength at 4-year follow-up. Weiss also demonstrated that good results can be obtained in patients with stage III disease who have evidence of lunate collapse. Despite good clinical outcomes, radiographic signs of continued collapse and degeneration are common. Although ulnar lengthening has demonstrated similar clinical outcomes, it is also associated with a higher complication rate. For this reason, radial shortening is the preferred joint-leveling method. Watson reported on the use of STT (triscaphe) fusion for stage III disease and noted nearly 80% of his patients had good or excellent pain relief at 51-month follow-up.14 Caution should be used when evaluating these results, as nearly 40% of his patients required additional procedures to achieve this outcome. Compared to STT fusion, SC fusion has demonstrated similar pain relief rates but slightly decreased motion. Currently, no long-term results are available on the use of capitate shortening with or without capitohamate arthrodesis. In a series of 51 patients who underwent vascular bundle implantation, 98% showed a reduction or resolution of pain at long-term follow-up. Again, these encouraging clinical results were not mirrored by radiographic improvement, as 20% had further degeneration and 10% had frank fragmentation. Results of the newer technique of distal radial vascular bone pedicle were noted previously. The expected outcome following PRC is 75° in the flexion/extension arc and grip strength of 75% of the opposite side. Pain relief has been demonstrated in 80% of patients who underwent PRC for Kienböck disease. As noted, a PRC can be converted successfully to wrist arthrodesis. Several other options for treatment have been reported. Ruby performed cancellous bone grafting supplemented by postoperative external fixation and found good pain relief in 80% of his patients.15 In patients with stage III disease and mechanical symptoms, arthroscopic debridement was found to decrease pain and increase motion. Finally, wrist denervation is a simple, safe option that can also be combined with other procedures to aid in postoperative pain reduction. In fact, denervation itself may provide much of the perceived pain reduction in cases where the dorsal capsule is incised to perform the index procedure. REFERENCESSection 9 of 9
Article Last Updated: Jul 11, 2007 |
