Volar and Dorsal Blood Supply to the Lunate: A Cadaveric Study

Although various studies have proposed vascular and mechanical factors, the etiology of Kienböck disease is unknown. Kienböck theorized that lunatomalacia resulted from traumatic disruption of blood supply and bony nutrition to the lunate. Extraosseous supply to the lunate, as far as volar or dorsal vessels are concerned, is still controversial. This study evaluated the extraosseous nutrient foramina from the dorsal and volar aspects of lunate specimens. A total of 913 specimens from the Hamann-Todd Osteological Collection in Cleveland, Ohio, were examined. The nutrient artery foramina on left and right lunate specimens were examined from dorsal and volar aspects. The number of nutrient artery foramen was tabulated. Age, sex, and race data were collected. Specimens were divided into groups according to the number of nutrient artery foramina, and the dorsal and volar foramina were compared. The average number of foramina on the dorsal aspect of the lunate (1.71) was greater than the volar aspect (1.64), except in specimens younger than 35 years. A greater number of specimens had 3 or more foramina on the dorsal side compared with the volar aspect. Based on this study, there was significant contribution of dorsal arterial vessels to the blood supply of lunate specimens older than 35 years, which contrasts with findings in earlier studies. The disruption of dorsal intercarpal and radiocarpal ligaments leading to the disruption of the dorsal arterial arches may contribute to vascular insufficiency of the lunate and should be evaluated further in the etiopathogenesis of Kienböck disease. [Orthopedics. 2021;44(2):e243-e247.].

Osteonecrosis of the Lunate: Kienböck Disease

Kienböck disease, osteonecrosis of the lunate, is a well-known but poorly understood complication seen by hand surgeons. This review presents the background and important patient-specific parameters of the disease and reviews the numerous treatment options that exist for the disease.

Juvenile Lunatomalacia—Is this Kienböck’s Disease?

An 8-year-old boy with stage III Kienböck’s disease was treated by immobilization of the wrist. He made a complete clinical recovery and serial X-rays and MRI scans demonstrated complete revascularization of the lunate which regained near normal architecture.

A hand therapy protocol for the treatment of lunate overload or early Kienbock's disease

We describe a hand therapy protocol aimed at unloading the wrist and increasing blood supply to the wrist, specifically to the lunate. The protocol was used in a series of patients with clinical radial wrist pain, dysfunction and changes on wrist imaging studies. The patients were not candidates for surgical treatment. Application of the therapy protocol improved objective and subjective parameters such as pain and motion, and may provide a viable treatment option for patients with lunate overload or early Kienbock's disease that are not candidates for surgery.

Etiology of Kienböck disease

The etiology of Kienböck disease is still unknown and, consequently, the ideal treatment is in doubt. Many different hypotheses have been suggested. There are reasons to believe that there are mechanical, vascular, and metabolic factors predisposing to the disease, and probably some factors triggering the development of the process. Among mechanical factors, the short ulna has been thought to be the most relevant. However, presently there are insufficient data to support a significant association between negative ulnar variance and Kienböck disease. With regard to vascular factors, anatomical studies have shown consistent dorsal and palmar arteries entering the bone, and thus, the most likely site for vascular impairment may be at the subchondral level. Many triggering factors have been proposed during the past years, but until this is truly clarified, finding the real cause of Kienböck disease will continue to be a real challenge.

Arthroplasty of the lunate using bone marrow mesenchymal stromal cells

Mesenchymal stromal cells have the potential to differentiate into a variety of mesenchymal tissues such as bone, cartilage and ligaments. The potential for the regeneration of bone with cartilage coverage has still not been achieved. We evaluated the ability of bone marrow mesenchymal stromal cells to regenerate osteochondral defects in the cavity of the lunate in an animal model. Autologous mesenchymal stromal cells were harvested from the iliac crest of New Zealand white rabbits and expanded in vitro. Total lunate excision was performed in 24 animals and the isolated cells were loaded onto scaffolds. Cell-free scaffolds were implanted in the lunate space of the right wrists of all animals, and the left lunate spaces were filled with predifferentiated, cell-loaded scaffolds. Radiographic and histological analyses were performed after two, six and 12 weeks. In addition, the animals were injected with a fluorescent agent every five days, starting at day 30. After two and six weeks there was no radiographic evidence of ossification, whereas after 12 weeks all animals showed radiographic evidence of ossification. Histological sections showed increasing evidence of cartilage-like cell formation at the edges and new bone tissue in the centre of the newly formed tissue in all groups. The histological examinations showed that bone tissue was located around the newly incorporated vascularisation. This study demonstrated that newly formed vascularisation is necessary for the regeneration of bone tissue with cell-loaded scaffolds.

Treatment of progressive necrosis of the lunate bone (Kienböck disease) after unsuccessful radial osteotomy

We report the treatment of three patients with stage 3 Kienböck disease that had advanced after radial shortening (n = 2) or lateral wedge osteotomy (n = 1). We shortened the capitate and fused the capitate and hamate, and applied a vascularised bone graft taken from the distal dorsal radius to the lunate. This was successful in all three patients.

Lunate revascularization with artery implantation and bone grafting

Treatment of Kienböck's disease encompasses a wide array of options. Proper staging is the first step to successful treatment. Revascularization of the lunate remains a viable option for the treatment of Lichtman stage II or IIIA Kienböck's disease. In this article, we review the indications for and the surgical technique used with a modified Hori procedure (vascular pedicle insertion with structural distal radius graft) for revascularization of the lunate.

The anatomy and vascularity of the lunate: considerations applied to Kienböck’s disease

PURPOSE

The purpose of this study was to assess the anatomy and vascularity of the lunate. The genesis of lunatomalacia requires some combination of vascular risk and mechanical predisposition. The findings will be correlated with the major existing theories of the cause of Kienböck's disease.

METHODS

We studied 27 cadaver upper limbs using latex injection and the Spalteholz technique. We investigated the blood supply to the lunate. In 24 wrists we evaluated the incidence and distribution of anatomic features, arthrosis, and soft tissue lesions. We correlated the lunate morphology and ligaments disruptions with the arthritic changes.

RESULTS

The lunate morphology results as classified by Antuña-Zapico were five type I (20.8%), 18 type II (75%) and one type III (4.2%). The lunate was found to have a separate facet for the hamate in 11 cases (45.8%). The most common size of the facet was found to be 3 mm (range, 3-6 mm). Arthrosis was identified with most frequency in the radius (88.2%) and lunate (94.1%). The triangular fibrocartilage complex was found torn in 58.3%, the lunotriquetral interosseous ligament was torn in 20.8% and the scapholunate interosseous ligament (SLIL) was torn in 54.2% of the wrists. There was a correlation between the presence of arthrosis at the hamate and the presence of a lunate facet (P=0.027) and a correlation between the presence of a tear in the SLIL and arthrosis in the scaphoid (P=0.002). The nutrient vessels entered the lunate through the dorsal and volar poles in all the specimens. The dorsal intercarpal and radiocarpal arches supply blood to the lunate from a plexus of vessels located directly over the lunate's dorsal pole. Vessels entered the dorsal aspect of the lunate through one to three foramina. One to five nutrient vessels were observed entering the volar pole through various ligament insertions, including the ligament of Testut-Kuentz (radio-scapho-lunate (RSL) ligament) and the radiolunate triquetrum ligament (or dorsoradial carpal ligament) and ulnar lunate triquetral ligament.

CONCLUSIONS

The lunate had consistent dorsal and palmar arteries entering the bone in all the specimens. The blood supply and foramina number is greater in the volar pole of the lunate than the dorsal pole. The lunate blood supply comes from different ligaments. In the etiopathogeny of Kienböck's disease it is possible that an acute or chronic, traumatic or non-traumatic injury of the vessel bearing ligaments, particularly because of their structure and the location of the RSL ligament, may have an important role in the appearance of lunate necrosis.

Avascular necrosis of the triquetrum: a case report

A case of total ischemia of the triquetrum after a crushing injury to the right wrist by a dumbbell is reported. He was treated conservatively with splinting and analgesia. There was complete clinical and radiological recovery after a follow-up of one year.

Lunate resection and vascularized Os pisiform transfer in Kienböck's Disease: an average of 10 years of follow-up study after Saffar's procedure

PURPOSE

To investigate the long-term results of lunate replacement by vascularized bone transfer in advanced Kienböck's disease.

METHODS

Twenty-one patients were reviewed (mean follow-up period +/- SD, 9.9 +/- 3.5 y) to analyze results after lunate replacement by vascularized pisiform transposition (Saffar's procedure) for Lichtman stages III and IV.

RESULTS

Pain was improved in 16 of 21 patients but range of motion did not improve after surgery. Range of motion was reduced to 68% and grip power to 80% of that of the opposite hand. At follow-up evaluation the mean score on the Disabilities of the Arm, Shoulder, and Hand Questionnaire was 22.3 +/- 17.9 and the mean Cooney score was 75.4 +/- 13.2. Radiologically, Lichtman stage persisted in 8, improved in 1, progressed in 8, and could not be evaluated in 3 patients. Two patients had radiologic signs of arthritis before surgery. At follow-up examination osteoarthritis was found in 50% of patients. The majority of degenerative changes were associated with carpal collapse.

CONCLUSIONS

The replacement of the lunate by vascularized pisiform transposition maintained preoperative ranges of motion. At follow-up examination both patient satisfaction and wrist function were high. In the long term, however, Saffar's procedure can restore alignment of the carpus only partly and also results in osteoarthritis in half of all patients.

The use of the 4 + 5 extensor compartmental vascularized bone graft for the treatment of Kienböck's disease

PURPOSE

The use of vascularized bone grafts for the treatment of Kienböck's disease may prevent ongoing lunate collapse and provide relief of wrist symptomatology. This study examines our experience with the use of the 4 + 5 extensor compartmental artery (ECA) bone graft for the treatment of Kienböck's disease.

METHODS

A retrospective review was performed of all patients having pedicled vascularized bone grafts for Kienböck's disease between 1991 and 2002. Only those patients who had reconstruction with a 4 + 5 ECA graft were included in the study. Presurgical and postsurgical measurements included range of motion, grip strength, and pain evaluation. Measurements of the radiolunate angle, radioscaphoid angle, Stahl's index, and carpal height ratio were taken from presurgical and final follow-up radiographs. Postsurgical magnetic resonance imaging scans were also examined to verify revascularization of the lunate. Statistical analysis was performed using Student's t test. A chi-square test was used to evaluate the effects of lunate revascularization on radiographic progression of disease. Twenty-six 4 + 5 ECA vascularized bone grafts were performed as treatment for Kienböck's disease. The average patient age was 32 years. At the time of surgery 12 patients were graded as stage II, 10 as IIIA, and 4 as IIIB. Mean follow-up time was 31 months.

RESULTS

At a mean follow-up of 3 months, motion improved from 68% to 71% of the unaffected side, grip strength improved from 50% to 89% of the unaffected side, and 92% of patients had significant improvement in their pain. Satisfactory results were seen in 85% of patients based on the Lichtman outcome score. Seventy-seven percent of patients showed no further collapse on postsurgical radiographs. Sixty-five percent of patients had follow-up magnetic resonance imaging scans at a mean of 20 months after surgery. Seventy-one percent of patients showed evidence of revascularization with improvement in the T2 and/or T1 signal.

CONCLUSIONS

The 4 + 5 ECA bone graft provides a reliable alternative for the treatment of Kienböck's disease and may aid in lunate revascularization.

The venous drainage of the lunate bone

One of the theories as to the etiology and pathogenesis of lunatomalacia (Kienböck's disease) is based on the presentation of an osseous compartment syndrome caused by a venous block in the pedicle. This gave us cause to examine the lunate bone more closely and to investigate possible anatomical causes for the disruption. For this purpose, ten hands were removed from cadavers proximal to the radiocarpal articular space. Through an artificial intraosseous canal, which did not touch the vascular structures of the lunate bone, epoxy could be injected under controlled conditions. The venous drainage, from the exit out of the bones up to the entrance into the comitant veins of the distal forearm, was exposed as a preparation under the microscope. In all preparations a dense plexus of small venous vessels was found at the palmar and dorsal periosteal face which has not previously been described in literature. As this wide plexus is woven into the solid palmar as well as into the dorsal connective tissue, it could be, as we suppose, the weak point of the venous drainage we have been looking for. It is easy to imagine that the rheological situation in this venous segment is impaired and an osseous compartment syndrome is induced by systemic factors as well as by local compression.

Open treatment of stage III Kienböck's disease with lunate revascularization compared with arthroscopic treatment without revascularization

PURPOSE

The goal of this study was to compare the results of open scaphocapitate fusion and revascularization with the results of arthroscopic scaphocapitate fusion and capitate pole excision.

TYPE OF STUDY

Prospective randomized study.

METHODS

Between April 1997 and January 2000, 16 consecutive patients (5 men and 11 women with a mean age of 31 years [range, 18 to 61]) presenting with Kienböck's disease stage IIIA and stage IIIB were randomized to either open scaphocapitate fusion and lunate revascularization (group I) or fully arthroscopic scaphocapitate fusion and capitate pole excision (group II) groups. Cannulated 3.5-mm ASIF screws were used for the purpose of scaphocapitate fixation in both groups. Operation time, hospital stay, time to fusion, range of wrist motion at final follow-up, grip strength, and return to unrestricted activities of daily living were evaluated at 33 months' follow-up.

RESULTS

The mean operating time (153 v 99 minutes), hospital stay (3.6 v 2.3 days), and return to unrestricted daily activities (15 v 5.8 weeks) were shorter in group II. Average time to radiographically evident fusion was shorter in group I (7.25 weeks v 9 weeks). There was a significant increase in grip strength and in range of motion at final follow-up in both groups, and the final grip strength and range of motion was not different between the groups. There were no major complications in either group.

CONCLUSIONS

Although the number of patients was small and the follow-up period was short, arthroscopic scaphocapitate fusion and capitate pole excision in stage IIIA and IIIB Kienböck's disease resulted in shorter operating time, shorter hospital stay, earlier return to unrestricted daily activities, and equal range of motion and grip strength as compared with open scaphocapitate fusion and lunate revascularization. Determination of specific surgical indications for the benefits of arthroscopic treatment of Kienböck's disease must be analyzed in larger studies.

Stage 3 Kienböck's disease: reconstruction of the fractured lunate using a free vascularized iliac bone graft and external fixation

Eighteen patients with stage 3 Kienböck's disease were treated by débridement of the necrotic core of the lunate and implantation of a free vascularized corticocancellous iliac bone. The wrist was stabilized with an external fixator during healing. The efficiency of the procedure for restoring the structure of the fractured lunate, preventing carpal collapse and improving the clinical outcome was assessed at a mean follow-up of 5 years. The graft became incorporated in the lunate in 16 of the 18 patients and no fracture of the reconstructed lunate or carpal collapse occurred in these cases. The graft did not integrate and was resorbed in the other two patients.

Lunate plasty for Kienböck's disease: use of a pedicled vascularised radial bone graft combined with shortening of the capitate and radius

We treated eight patients with Kienböck's disease (two patients each with stage 1, 2, 3a and 3b disease by Lichtman's classification) by removing a pedicled, vascularised bone segment from the dorsal aspect of the distal radius and engrafting it into the lunate. Additional shortening of the radius was performed in patients with the ulna-minus or null variant. Shortening of the capitate and capito-hamate fusion were also performed in patients with stage 3 disease. All patients were relieved of their wrist pain at rest and during movement, and the mean grip strength increased from 37% of that in the contralateral hand before surgery to 80% after surgery. The mean post-operative range of motion in the affected wrist was 92% of that in the opposite wrist in patients with stage 1 and 2 disease, and 53% in patients with stage 3 disease. Post-operative assessment revealed that four patients had excellent results, three had good results, and one had a fair result.

Vascularity of the carpus

Relatively few studies investigating the vascular patterns of the carpus have been performed. Technical difficulties in identifying small vessels in three dimensions and in determining their location within the thick ligaments about the wrist have led to conflicting anatomic reports. Studies on cadavers in which improved techniques with arterial injection, chemical debridement, and decalcification were used allowed the arterial anatomy of the carpus to be delineated more accurately. The current authors review these arterial patterns, with attention given to the extraosseous and intraosseous vascularities.

[Resection of nerve of wrist combining replacement of lunate with bone cement prosthesis in treatment of Kienbock's disease]

OBJECTIVE

There are various methods used to treat the Kienbock's disease with various outcomes. This study investigated the effect of combining acrylic lunate prosthesis replacement with resection of articular branches to wrist from anterior and dorsal interosseous nerve.

METHODS

From January 1992 to January 1997, six cases were included. All of the patients were in stage III according to Lichtman's classification. Besides replacement of the acrylic lunate prosthesis, segment of the pure sensory branches from anterior and posterior interosseous nerves were resected.

RESULTS

Follow-up for 10 to 54 months (an average of 32 months) the pain was relieved in all patients except one. The range of movement of wrists were as followings: The extension of the wrist was 20 to 35 degrees (an average of 26 degrees) and flexion was 20 to 35 degrees (an average of 32 degrees). There was no improvement in radial and ulnar deviation.

CONCLUSION

Lunate prosthesis replacement combined with resection of articular branches to wrist resulted in a painless wrist and was a satisfactory method.

[Possibilities for revascularization in early and late stage lunate malacia]

There are various biomechanical procedures for the treatment of lunate necrosis in the literature, but only a few deal with the possible revascularisation of the bone. We used the second dorsal metacarpal vascular bundle implantation technique in different stages of Kienböck's disease. Since 1990, twelve patients were treated by this method. In stage I-II according to Lichtman, we implanted the vessels in the lunate after excochleation and cancellous bone grafting, in stage III we used a modified form of the Graner operation and revascularised the proximalised part of the capitate. In the first group, six patients, we observed significant improvement in five cases clinically, radiologically confirmed stagnation of the process in four cases. In the second group of six patients, the clinical symptoms improved in four cases, three patients had to change work and one patient developed a pseudarthrosis between the capitate and corticocancellous block, but the proximalised part of capitate survived in all cases. Vascular bundle implantation can be a helpful method in early stages of lunate necrosis, helping to slow or to stop the progression of the disease.

[Intracarpal revascularization arthrodesis with transposition of the capitate bone (Graner type II)]

Necrosis of the lunate requires surgery when it is painful and disabling. Decoulx's stage III is too often beyond reconstructive surgery (lengthening of the ulna, shortening of the radius), while such disabling procedures as wrist arthrodesis are not indicated yet. The intracarpal revascularizing arthrodesis with transposition of the capitate (described by Graner in 1966) is to be considered at this stage. The creation of a new condylar arch coated with cartilage, resembling the physiologic arch, and the preservation of the radio-carpal mobility, allows the return of sufficient motion and strength for everyday needs. The wrist often gets painfree; this procedure should thus be considered as a palliative salvage operation, none the less useful in young manual workers.

[Arterial vascularization of the semilunar bone]

The gross examination of 41 dried lunates and the dissection of 50 minimum injected forearms allowed the author to give a general statement of the blood supply of the lunate. On the volar aspect of the hand, 2 or 3 vessels coming from the ramus carpeus volaris and/or the radial artery run downward and penetrate the bone through a big foramen and several smaller around. On the dorsal aspect, 2 or 3 minute branches arise from the dorsal carpal arch and penetrate the triangular posterior surface of the lunate beneath the carpal joint; more infrequently 2 twigs may be traced along both scaphoid-lunate and triquetrumlunate joints. The interosseous artery sends some conspicuous branches to the posterior margin of the radius and the dorsum of the lunate. The volar group appeared to be the most important contributor to the blood supply and the big volar foramen should be named "hilus" of the lunate. It must be emphasized that the nutrient vessels enter the foramen above the upper margin of the transverse carpal ligament; so, no crowding in the carpal tunnel can be liable for "avascular necrosis" of the lunate.

Sheet plastination of the vascularity of the lunate bone--a morphological study

Using the method of sheet plastination, the vascularity of the lunate bone can be investigated and analyzed. By intraosseous injection, the deep and superficial venous systems are visualized. Transparent sheets with slices of embedded specimens show a three-dimensional presentation of the vascularity of the human carpus different in functional aspects. Comparing hands with a normal and extended wrist position, three mechanisms of impairment of the venous drainage are observed. The anatomical results of this investigation support the hypothesis that venous congestion, resulting from intraosseous hypertension, plays a role in the development of the necrosis of the lunate bone.

[Vascular pedicled transposition of the pisiform bone for treatment of lunate malacia]

In a prospective study we investigated the results of 18 patients with Kienböck's disease stage II as defined by Decoulx, treated with transposition of the pedicled pisiform. In eight cases of minus variance of the ulna, a radius shortening osteotomy was performed. There was an average follow-up of 30 months, X-ray investigations were done every six months after operation. 17 patients had less pain, 14 patients showed an improved range of motion of 30 degrees. Magnetic resonance imaging proved vitalizing of the pisiforme in 16 cases.

Further investigations of the intraosseous pressure characteristics in necrotic lunates (Kienböck's disease)

To confirm the hypothesis that venous congestion plays a role in idiopathic lunate necrosis (Kienböck's disease), intraosseous pressure in 12 normal and 12 necrotic lunates was measured. Intraosseous pressure in the capitate of 12 healthy subjects served as reference measurement. The intraosseous pressure was recorded in neutral position and 60 degrees extension of the wrist under normotensive conditions and during venous stasis. In all groups, the mean intraosseous pressure rose significantly with extension of the wrist, with the largest increase being 92.3 mmHg for necrotic lunates, followed by 40.3 mmHg for normal lunates, 6.9 mmHg for normal capitates and during venous stasis, 26.6 mmHg for necrotic lunates, 26.1 mmHg for normal lunates, and 5.9 mmHg for normal capitates. In some necrotic lunates, the intraosseous pressure during extension exceeded the arterial blood pressure, which can be explained by mechanical deformation of the bone. In neutral position, no significant differences in pressure were found between normal lunates and capitates. A significant difference was found for venous stasis and extension. The intraosseous pressure rise in the normal lunate in extension was slightly higher than the pressure found during venous stasis. The intraosseous pressure differed significantly (by 56.9 mmHg) between normal and necrotic lunates in extension. These data support the hypothesis that impairment of venous drainage plays a role in lunate necrosis and that the lunate can be considered as a venous bone at risk.

Vascular bundle implantation into bone for aseptic necrosis of the lunate

Since April 1986, implantation of a vascular bundle containing the ramus carpeus dorsalis of the interosseal anterior artery and vein into the lunate has been undertaken for aseptic necrosis of the lunate bone. A series of 11 cases were performed in East-South Hospital with satisfactory results. The average follow-up period was 36 months. A series of follow-up roentgenograms reveal that necrosis of the lunate bone is being continuously repaired. Fourteen months postoperative, the following results are obtained: (1) the sclerosis of the lunate bone has completely disappeared on the roentgenograms, (2) the architecture and density of the lunate bone have returned to normal on the roentgenograms, (3) technically colorized X-ray films show that lunate bone density decreases after the operation (the decreasing range is 20 to 44 Gray scale [mean, 30.3 +/- 2.4 Gray scale]) and that the cyst formations on the lunate bone have completely disappeared postoperatively, and (4) pain in the affected wrists disappeared and patients have returned to their former work, including manual labor. The necrotized lunate bones are healed. Anatomic study shows that the presence of the ramus carpeus dorsalis of the interosseal anterior artery and vein on the wrist is 100%, and the structure as well as location of the ramus carpeus dorsalis has little anatomic variation and is long enough to be transplanted into the lunate bone.

[Intraosseous pressure measurement in Kienboeck's disease--initial findings]

Intraosseous pressure was measured under standardized and different functional conditions in 11 necrotic lunates in different stages of the disease and in 11 viable lunates. Both the viable and the necrotic lunates show a significant increase of the pressure, if the wrist is brought into dorsiflexion. Both groups do not differ significantly, but the mean value of the necrotic group exceeds that of the viable group clearly. There might have some technical problems in measuring. Venous stasis by tourniquet provoked increase of pressure, too. The increase of pressure both in dorsiflexion and in venous stasis is evidence of venous drainage. Dorsiflexion impairs the venous drainage of the lunate, which promotes necrosis. The increase of intraosseous pressure in necrotic lunates can be understood as a failure of the physiologic regulation of the intraosseous pressure by moving the wrist and cause of necrotic changes.

Kienböck's disease, early stage 3--height reconstruction and core revascularization of the lunate

Early stage 3 Kienböck's disease has been treated by inner débridement, recontouring, height reconstruction, bone grafting and core revascularization of the lunate; additional procedures included temporary external fixation of the wrist and/or shortening osteotomy of the radius in selected cases. 26 patients, representing an uninterrupted series of 28 procedures, were followed-up for an average of 6.7 years (range 2.5-9.3 years) with periodic clinical and radiographic evaluations until they reached the final comprehensive assessment that included trispiral tomography and MRI. Every patient was subjectively improved, pleased with the result and able to resume his previous job. Pain intensity, rated on a zero to five scale, improved from 2.5 points pre-operatively to a final score of 0.8 points. Wrist motion gained slightly. Grip strength improved significantly. Lunate reconstruction proved successful in 37% of the cases; in an additional 23%, the disease process was stabilized. Carpal height decreased 4.7%; ulnar translation was not substantially altered. Arthrosis increased postoperatively in 55%, remained unchanged in 36% and progressed in 9%. Overall, 43% good and excellent, 43% fair and 14% poor results were observed.

Vascularity of the lunate. Anatomic studies and implications for the development of osteonecrosis

Osteonecrosis of the lunate is well established as the pathologic entity underlying the clinical condition known as Kienböck's disease. Consequently, the extraosseous and intraosseous blood supplies to the lunate have been well studied. A series of three palmar and three dorsal arterial arches provide a consistent volar supply to the lunate, and a frequent, but inconsistent, dorsal supply. Volar and dorsal foramina each generally contribute one to two vessels to a volar and dorsal intraosseous arterial network. The dorsal and volar arterial systems anastomose distal to the midline of the lunate; however, in as many as 7.5% of lunates, no anastomosis my be present. Between 7% and 26% of lunates may lack either a volar or dorsal arterial supply. These findings have significant implications regarding possible mechanisms for the development of osteonecrosis and the treatment of Kienböck's disease.

Revascularization procedures in the treatment of Kienböck's disease

Lunate revascularization by means of vascular bundle implantation is one of the useful procedures for stages I and II Kienböck's disease, but for stage III, it should be combined with some biomechanical procedure or partial carpal fusion. There is no indication for this procedure in stage IV disease.

Review of treatment results for Kienbock's disease

A review of the literature reveals that Kienbock's disease has been treated in many different ways. Excision of the lunate, with or without replacement arthroplasty, and joint-leveling procedures (radial shortening or ulnar lengthening) are the most popular procedures, but other methods of treatment (nonoperative, wrist denervation, lunate revascularization, intercarpal arthrodesis and proximal-row carpectomy) have also been performed. Based on our current understanding of the etiology, a joint-leveling procedure seems to make the most sense when surgery is indicated. However, other procedures have yielded a high success rate as well.

[Ischemic necrosis of the lunate. The value of nuclear spin tomography in comparison to conventional roentgen studies]

Conventional radiographs do not always make it possible to confirm a diagnosis of ischemic necrosis of the lunate in the early stages of disease. For these doubtful cases MRI is justifiable in addition, to diagnose or to rule out ischemic necrosis of the lunate.

[Aseptic necrosis of the lunate bone. Etiology, clinical aspects, stage-adjusted therapy]

The development of the aseptic necrosis of the lunate bone is so far not fully understood. Therapeutical problems result from the very late discovery of the disease and from the central position in the carpal bone system. Bad long-term-results come out of therapies not able to revitalize the lunate bone. Therefore the therapeutical goal attempted must be to keep the structures of the bone alive and to avoid major pathological changes of the whole carpal bone system. More or less good results could be shown for these patients with a total break-down of the lunate bone treated with the intercarpal-arthrodesis described by Graner.

[Graner's intercarpal arthrodesis as therapy of aseptic lunate bone necrosis]

From 1978 till 1989 at the Department of Orthopaedics (University of Graz, Faculty of Medicine, Division of Surgery) 25 patients were operated for the reason of an avascular necrosis of the lunate bone when the bone structures were already destroyed. The form of therapy was the intercarpal-arthrodesis, developed by Orlando Graner 1966, in a slightly modified way. On the one hand through creating an intercarpal block it is possible to create more or less plain sides of the radiocarpal joint and on the other hand one can stop the carpal collapse what explains long-term-results rather acceptable. The most important disadvantage of this form of therapy is the often found loss of range of movement in the operated radiocarpal joint.

Magnetic resonance imaging in the assessment of revascularization in Kienbock's disease. A preliminary report

A 25-year-old man with stage II Kienbock's disease of his left lunate underwent an initial period of immobilization. He was subsequently treated by ulnar lengthening, with a good outcome. Magnetic resonance imaging (MRI) was utilized to demonstrate the lack of improvement with cast immobilization and the revascularization that followed surgical treatment. This new application of MRI in cases of avascular necrosis of the lunate may be helpful in the early identification of revascularization.

Late treatment of a dorsal transscaphoid, transtriquetral perilunate wrist dislocation with avascular changes of the lunate

The outcome of delayed treatment of an unreduced transscaphoid, transtriquetral, perilunate fracture dislocation of the carpus is unpredictable. Long-term follow-up observations in a 22-year-old man treated three months postinjury showed changes in the lunate consistent with avascular necrosis at the time of open reduction and internal fixation. Early resolution of this was evident by nine months, and complete resolution was seen at the follow-up examination (four years and two months). Despite delay in treatment, this patient had full, pain-free wrist motion. Consequently, avascular changes of the carpus following wrist dislocation do not preclude a good result. Anatomic reduction of the scaphoid, as well as the midcarpal joint, and restoration of the articular surface of the lunate, are most important in determining prognosis.

Kienbock's disease

Kienbock's disease (lunate malacia) is an unusual but not rare cause of wrist pain. It is manifested by avascular necrosis and subsequent disintegration of the lunate. Despite recognition of this disease entity for the past 70 years, its cause is still debated. Most investigators relate it to a stress fracture that leads to devascularization of the major segment of the lunate if the lunate is supplied by one volar vessel. The classification of Kienbock's disease is based on its roentgenologic appearance. Stage 1 consists of small fracture lines. Stage 2 is rarification along the fracture line, usually on the volar pole. Stage 3 shows sclerosis of the bone dorsal to the fracture site. Stage 4 shows sclerosis of the bone dorsal to the fracture site, and collapse and secondary fracture with loss of architectural integrity of the lunate. Stage 5 shows secondary arthritic changes of the radius. Treatment is categorized into two general types. The first is an attempt to allow revascularization of the lunate be relieving the compression forces. This is accomplished by lengthening the ulna and/or shortening the radius, with capitate-hamate fusion; or by shortening the capitate and fusing the capitate and hamate. These procedures are performed in the early stages of Kienbock's disease. The second type of treatment, used in more advanced cases, includes excision of the lunate: replacement of the lunate by prosthesis, with or without capitate shortening and/or capitate-hamate fusion; and various types of intercarpal fusion.

The vascularity of the wrist. Identification of arterial patterns at risk

The intraosseous and extraosseous vascularity of carpal bones was studied in 75 cadaver limbs. Vascular patterns were correlated with the clinical incidence of avascular necrosis, and at-risk patterns of vascularity were identified. The carpal bones were found to fall into three groups. Group 1, which consisted of the scaphoid, the capitate, and eight percent of the lunates, had either vessels entering only one surface or large areas of bone that were dependent on a single vessel. This group was the most vulnerable to posttraumatic avascular necrosis. The bones of Group 2, the hamate and the trapezoid, were characterized by the absence of internal anastomoses. Although these bones are theoretically at risk, they do not undergo avascular necrosis. Group 3 bones, which included the trapezium, the triquetrum, the pisiform, and 92% of the lunates, had rich internal anastomoses and were at least risk of undergoing avascular necrosis. Examination of the arterial anatomy of bones that undergo avascular necrosis in other regions of the body led to a classification based on the types of vascular interruptions that place particular bones at risk. In some, i.e., the scaphoid and the capitate, a pure intraosseous disruption resulted in avascular necrosis; in others, i.e., the femoral head and a small percentage of lunates, an extraosseous disruption was sufficient to produce avascular necrosis. A third class, which included the talus and the majority of lunates, had an adequate intraosseous blood supply and good extraosseous vascularity. This pattern required severe extraosseous or a combination of intraosseous and extraosseous injury to lead to avascular necrosis.

Kienböck's disease

Recent anatomic and biomechanical studies have contributed to a better understanding of Kienb ock 's disease. The operative alternative, if based on a classification of the severity of disease, should provide a more logical and systematic approach to patients with this difficult problem.

Radial shortening for the treatment of Kienböck's disease--a 5- to 10-year follow-up

Kienböck's disease is probably caused by microfractures or stress fractures developing within the lunate. In about 32% of the population, the vascular pattern to the lunate is such that after fracture they are vulnerable to a secondary aseptic necrosis of the lunate. The high incidence of Kienböck's disease in patients with an ulnar minus variant wrist may be explained by an increased stress on the lunate in dorsiflexion and ulnar deviation. This study is a 5- to 10-year follow-up of patients with early stages of Kienböck's disease and ulnar minus variant treated by radial shortening procedures. Eleven of the 12 patients were satisfied with their treatment and showed functional improvement. These patients returned to their normal activities. Grip strength was satisfactory, and range of motion improved following surgery.

[Extrinsic and intrinsic vascularization of the scaphoid and lunate bones]

This work was performed on 50 wrist dissections. The scaphoid is situated in the territory of the radial artery. Two extracapsular vascular pedicles are constant: --the lateral pedicle arises in the anatomical snuff-box, --the anterior pedicle arises in the "wrist pulse" area and passes behind the flexor carpi radialis. It lies on the radio-carpal ligaments. THe intra-capsular pedicles approach the scaphoid from its proximal pole. There are anastomoses and they lie on the deep dorsal and palmar ligaments. The multiple anastomotic branches may form an inconstant pedicle. The lunate is supplied by frequent but inconstant arterial pedicles. They are palmar and dorsal, superficial and deep (intra-capsular), distal and proximal, and lie on the radiocarpal ligaments. They originate from the three principal arteries of the hand or their branches. Anastomotic connections exist between them; if the vascular arrangement is complete, it is very reliable; when it is incomplete, it predisposes to Kienböck's disease. There is a close functional relationship between the scaphoid and the lunate. The vulnerability of these two bones to trauma which can also affect their ligaments explains the relative frequency of ischemic complications.

Kienböck's disease in cerebral palsy

Five cases of Kienböck's disease occurring in a group of fifty-three adults with cerebral palsy are described. The increased incidence of the disease is attributed to the flexed posture habitual in the affected wrist and to an effect on the pattern of blood supply to the lunate.

[Restitution of lunate bone necrosis in a child (author's transl)]

We reported a case of aseptic bone-cartilage necrosis of the os lunatum in a child. All indications for constitutional disposition, anatomic variations in the wrist joint or a traumatizing of the wrist joint were absent. Etiologically, a disturbance in vascularization could be assumed. The increased repair potential in children apparently led to a restitution which has not been observed in adults.

[Anatomical investigation of the blood-supply of the lunate bone (author's transl)]

The lunate bone receives its blood-supply via a palmar and a dorsal vascular and fibrous strand. When the wrist is extended the dorsal vessels are caught in a kind of vice formed by the radius and the capitate bone and compressed up to complete occlusion. This mechanism, important for the pathogenesis of Kienböck's disease, is demonstrated on anatomical specimens.