Clinical and experimental study of shortening osteotomy of forearm bone(s) in Kienb?ck's disease

Sixty-nine patients with Kienb?ck's disease were surgically treated from 1972 to 1987. Eleven patients with ulnar minus variance, 48 with neutral variance and 10 with ulnar plus variance were treated with shortening osteotomy of the radius. Ten patients with ulnar plus variance were treated with shortening osteotomy of both the radius and ulna. All cases were followed up from one to eleven years. Satisfactory improvement was attained in 85% of cases. Radiologic evaluation showed revascularization of the lunate in 94%. Collapse of the lunate did not progress in 60%. In 14 wrists of adult Japanese monkeys, ulnar minus and plus variants were created, and radial-ulna compression force was measured with intraarticular pressure sensors. Intraarticular forces were then measured following shortening osteotomy of the forearm bone(s). These procedures uniformly decreased pressure in the radial-ulna joint.     

Sagittal wrist motion of carpal bones following intraarticular fractures of the distal radius

Forty patients (mean age, 37 years) with intraarticular C2 and C3 Colles fractures were treated by open reduction, internal fixation and bone grafting. At a mean follow-up of 8 years radiocarpal and midcarpal motion was evaluated, the depth of the articular surface of the distal radius in the sagittal plane was measured and the presence of arthritis was noted. The fractures healed with a mean palmar tilt of 6 degrees , a mean ulnar tilt of 18 degrees and ulna variance within 1 mm of the contralateral side. The depth of the articular surface of the distal radius was 1.3 mm greater than the uninvolved side. Measurement of carpal bone angles relative to the radius in maximum flexion and extension revealed lunate extension of 23 degrees , lunate flexion of 15 degrees , capitate extension of 62 degrees , capitate flexion of 40 degrees . There was a significant correlation between articular surface depth and radiocarpal motion.     

Arthroscopic treatment of the ulnar impaction syndrome

The ulnar impaction syndrome is due to hyperpressure in the ulnocarpal joint. It occurs most frequently following distal radial fractures with shortening, but can also be secondary to a primitive length discrepancy between a short radius and a long ulna (positive ulnar variance). Symptoms and clinical findings, even though characteristic, are not specific. Standard X rays show a positive ulnar variance, and sometimes a hyperpressure cyst in the lunate. CT arthroscan and MRI studies demonstrate indirect signs of hyperpressure. If medical treatment fails to improve the condition, the choice surgical technique is arthroscopic, allowing debridement of the TFCC central tear, and shortening of the horizontal aspect of the ulnar head.     

Ulnar lengthening and shortening

Alteration in length of the distal ulna may provide an attractive alternative to more destructive procedures commonly used for the treatment of mechanical and degenerative problems at the distal radioulnar joint. Ulnar recession has shown effectiveness in ulnolunate impingement, triangular fibrocartilage tears, and symptomatic ulnar plus variance. It has also been effective in chondromalacia of the ulnar head in the sigmoid notch and in unstable distal radioulnar joints where recession alters the bearing surface and tightens the ulnocarpal ligamentous complex. Ulnar lengthening has been efficacious in relieving the symptoms of Kienb?ck's disease by decompressing the involved portion of the lunate and distributing joint compressive force on the triquetrum and medial lunate articular surfaces. It may also be of value in some instances of NDCI associated with an ulnar minus variant.     

The changes in bone mineral density of the forearm and distal radius–ulna subcortical bone due to ulnar variance

The aim of this study was to evaluate the changes in subcortical bone mineralization of the distal radius and ulna in the presence of negative ulnar variance. A total of 77 healthy right hand-dominant volunteers [34 women and 43 men of mean age 38 ± 14.8 years (range 14–71)] were enrolled in this study. Bilateral bone mineral density (BMD) and bone mineral density ratio (BMDR) measurements of the distal radius and ulna were performed by using dual energy X-ray absorptiometry. We found a significant decrease of ulnar subcortical BMD and BMDR subcortical in the dominant forearms of the subjects with negative ulnar variance when compared to that of subjects with neutral ulnar variance (P < 0.02). But this difference was not seen on the non-dominant side. There was no significant difference in BMDRs between the dominant and non-dominant forearms for all subjects. Radial and ulnar subcortical BMD values were significantly different between dominant and non-dominant forearms in subjects with bilateral neutral ulnar variance, whereas not significantly different in subjects with bilateral negative ulnar variance. The increase found in the BMD value of radial subcortical bone in subjects with negative ulnar variance may be due to the indirect shift of axial forces through the ulna to radius.     

Radiographic changes in wrists with ulnar plus variance observed over a ten-year period

This study provides additional radiographic information concerning the long-term effect of ulnar impingement. Films of 198 wrists of 102 patients with vibration disease observed over ten or more years were reviewed. All the wrists showed ulnar plus variance of more than 0 mm except seven. Degenerative changes were found in 58 wrists and were seen only on the ulnar side of the wrist, especially in the ulnoproximal area of the lunate. Most of the degenerative changes in the wrists with ulnar plus variance had progressed or changed during the ten or more years. Ulnar plus variance may play an important role in inducing or causing progression of degenerative change in the wrist.     

A finite-element analysis of Kienbock's disease

A finite-element analysis model of the lunate was established using geometrical data obtained from cadaveric bones. The lunate cortex was modelled with triangular and quadrilateral elements and its intraosseous structure was represented either as a homogenous elastic structure or as an anisotropic network of cortical bone beams (trabeculae) with different orientations and thicknesses. Compressive loads applied to the metacarpus were distributed in the carpus against the fixed radius and ulna. The ulnar variance had a strong influence on the ratios radiolunate/ulnolunate total load and peak pressures. The distribution of internal stresses was markedly affected by the lunate uncovering index. The evolution of a simulated incomplete fracture was dramatically influenced by morphological parameters: with positive ulnar variance, the fracture did not progress, but in the presence of three associated conditions, negative ulnar variance, a high lunate uncovering index and angulated trabeculae, the fracture progressed and the proximal part of the lunate collapsed. This study supports the concept that some lunates are predisposed to Kienb?ck's disease because their anatomy induces abnormal internal stresses, which allow an incomplete fracture to progress, under heavy loading conditions, and cause progressive collapse and localised trabecular osteonecrosis.     

MSCT图像重建技术在尺骨撞击综合征中的应用

目的评价MSCT图像重建技术在尺骨撞击综合征诊断中的应用价值。方法回顾性分析经腕关节镜检查证实的18例尺骨撞击综合征患者MSCT图像重建技术及标准后前位X线平片检查的影像资料,对尺骨变异、月骨及三角骨异常变化进行统计学分析。结果⑴MSCT图像重建技术及标准后前位X线平片检查测量出的尺骨变异差异无统计学意义(t=0.3562,P>0.05);⑵MSCT图像重建显示18例尺骨阳性变异15例,占总例数83.3%,其中阳性变异超过2 mm者11例,占总阳性变异的73.3%;中性及阴性变异3例,占总例数16.7%;⑶MSCT重建技术显示月骨和/或三角骨异常变化14例,占总例数77.8%,其中单纯月骨异常变化8例,月骨及三角骨同时异常变化5例,单纯三角骨异常变化1例。标准后前位X线平片能显示月骨和/或三角骨异常变化10例,占总例数55.6%,其中单纯月骨异常变化6例、月骨及三角骨同时异常变化4例,无单纯三角骨异常变化;⑷MSCT图像重建技术测量尺骨阳性伴月骨及三角骨异常变化14例,占总例数77.8%,尺骨阳性变异不伴月骨及三角骨异常变化1例,占总例数5.6%。阳性变异大于2 mm伴月骨及三角骨异常变化11例,占总例数61.1%,月骨及三角骨异常变化例数的78.6%。无尺骨中性及阴性变异伴月骨及三角骨异常变化。结论MSCT图像重建技术及后前位X线平片测量尺骨变异无统计学差异;尺骨撞击综合征发展过程中尺骨阳性变异呈易感因素;尺骨阳性变异大于2 mm时易引起月骨、三角骨异常变化;MSCT图像重建技术可以很好地显示尺骨变异及月骨、三角骨骨质硬化情况。     

Force transmission through the distal ulna: effect of ulnar variance, lunate fossa angulation, and radial and palmar tilt of the distal radius.

The relationship between the amount of force transmitted through the distal ulna and seven radiologically apparent anatomic parameters (ulnar variance, radial tilt, palmar tilt, lunate fossa angulation, carpal height, carpal ulnar distance, and ulnar head inclination) was examined in 58 fresh cadaver forearms. A positive, although very weak, relationship was found between the amount of force and the ulnar variance (r = 0.44). This suggests that a clinically more positive ulnar variant wrist will not necessarily cause more force to be transmitted to the head of the ulna than a wrist with a more negative ulnar variance, primarily because the triangular fibro-cartilage complex is thicker in arms with a more negative ulnar variance. Changes in ulnar variance of a forearm due to ulnar lengthening or radial shortening do, however, dramatically alter the force transmission. No other relationships were found between the ulnar force and the other radiologic parameters.     

Ulnar variance and subchondral bone mineralization patterns in the distal articular surface of the radius

PURPOSE: Based on biomechanical experiments in specimens it is accepted widely that ulnar length determines loading of distal articular surface of the radius with ulna-minus variance increasing and ulna-plus variance decreasing the loading of the lunate compartment. Nevertheless a direct assessment of the actual loading conditions in the living is currently impossible. The aim of the present study is therefore to evaluate subchondral bone mineralization patterns to provide further information about the role of ulnar length in load transmission through the radiocarpal joint. METHODS: Twelve wrists of healthy subjects with an average age of 33 years and an average congenital ulna-minus wrist of -2.8 mm (range, -4 to -1 mm) were examined by means of computed tomography-osteoabsorptiometry. A further 5 wrists in healthy subjects with an average age of 52 years and an average congenital ulna-plus variance of +3.0 mm (range, +2 to +4 mm) were examined with the same technique. Seventeen wrist joints of 9 healthy subjects with ulna-zero variance were examined in the control group. RESULTS: The results show a mainly lunate mineralization pattern in subjects with ulna-minus wrists in 75% of the cases, which is more frequent than in subjects with ulna-zero wrists. The results in ulna-plus variance show a mainly scaphoid mineralization pattern in 100% of cases. The differences in mineralization patterns are statistically significant. CONCLUSIONS: We conclude from these morphologic results in living subjects that ulnar length determines the peak mineralization patterns of the distal articular surface of the radius with a relatively lesser loading of the lunate fossa in ulna-plus variance and a relatively higher loading history in most cases of ulna-minus variance. The hypothesis, however, that ulna-minus variance is always a sign of a relatively higher loading history of the lunate fossa cannot be supported.     

The shape of the triangular fibrocartilage during pronation-supination

We studied the changes in the shape of the triangular fibrocartilage (TFC: disc proper) which occur during forearm rotation in disarticulated and articulated wrists. The influence of artificial 3mm ulnar lengthening on distortion of the disc was also examined. In the disarticulated wrists, slight distortion of the central and radial portions of the TFC was observed in the ulnar neutral variance specimens. More distortion was noted in the radial and central portions of the TFC in specimens with positive ulnar variance or with the ulna lengthened. However, in the articulated wrist, the TFC demonstrated little change in shape during pronosupination even in the ulnar positive variance wrists or with the ulna lengthened. There was no significant change in palmar and dorsal peripheral lengths of the TFC in ulnar neutral, ulnar positive or ulna-lengthened specimens at three rotatory positions of the forearm. These findings suggest that changes in ulnar variance which occur during forearm rotation can produce distortion on the TFC, but the carpus helps to maintain the shape of the TFC during pronation-supination, even with positive ulnar variance.     

Kienböck's disease with negative ulnar variance: surgical treatment with ulnar lengthening

The aim of the study was to analyse the results of surgical treatment of ulnar lengthening in patients with negative ulnar variance and Kienböck's disease. We report 5 case treated from 1994 to 1998. We evaluated pain, range of motion, functional disability and the progression of the disease by radiologically assessing the lunate and the ulnar variance. The minimum follow-up was 3–5 years. The patients treated by ulnar lengthening had no pain and obtained a good range of motion. No ulnar nonunions were reported and only one patient had residual ulna minus variant at follow-up examination. We recommend an ulnar lengthening procedure for patients with negative ulnar variance and Kienböck's disease.     

Aged-onset Kienböck's disease

Summary Kienböck's disease with onset after 50 years of age was studied. Of 127 patients with Kineböck's disease seen over the past 30 years, the cases of 15 (12 female, 3 male) were analyzed. The average age of onset was 58.3 years. Five specimens were obtained operatively in which necrosis of the lunate bone mixed with empty lacunae was identified, as was bony remodelling. Ulnar variance in the aged diseased group (group A) was smaller than that of the aged control group (group C). Moreover, it was noteworthy that the variance among aged controls (group C) was higher than among the young controls (group D). The metacarpal index of the patients with aged-onset Kienböck's disease was markedly lower than that of the young. Considering the increase of ulnar variance with age, the persistence of minus variance and the presence of osteoporosis might make the lunate bone susceptible to injury.     

Arthroscopic treatment of ulnar impaction syndrome

Ulnar impaction syndrome occurs in the setting of a central traumatic or degenerative defect in the triangular fibrocartilage complex in patients with ulnar positive variance. Chondral and subchondral edema, mechanical impingement of the articular disc, and chondromalacia of the distal ulna, proximal lunate, and proximal triquetrum produce symptoms with activity that do not improve with rest. Decreasing ulnocarpal load-sharing across the wrist with recession of the distal ulna is necessary to relieve symptoms in the majority of patients. Arthroscopic treatment with triangular fibrocartilage complex debridement and arthroscopic ulnar wafer resection is an effective treatment for ulnar impaction syndrome. It affords a single-stage, minimally invasive approach, with similar efficacy and fewer complications than open wafer resection or ulnar shortening osteotomy.     

Motion analysis in two dimensions of radial-ulnar deviation of type I versus type II lunates

The motions of 2 different types of lunate (type I, no medial hamate facet; type II, medial hamate facet) were evaluated and compared during radial-ulnar deviation of the wrist using radiography and magnetic resonance imaging. Ten right wrists (5 type I and 5 type II lunates) were studied using posteroanterior and lateral x-rays. Six of the 10 normal volunteers (3 type I and 3 type II lunates) were studied using magnetic resonance imaging in 6 positions of radial-ulnar deviation. In the radiographic study the ulnar shift ratio of the lunate (USR), the shortest distance between the proximal ulnar tip of the lunate and the distal ulnar edge of the sigmoid notch of the radius (R-L), the closest distance between the distal ulnar tip of the lunate and the proximal pole of the hamate (L-H), the radius of curvature of the proximal head of the capitate (Cr) on posteroanterior view, and the radiolunate angle on lateral view were measured in each wrist in each of the 6 positions. There were statistically significant differences between type I and II lunates with regard to average maximum ulnar deviation of USR and R-L, total change of USR, R-L distance and L-H distance, average L-H distance and Cr distance in all positions, and average radiolunate angle in neutral and 15 degrees ulnar deviation. In the magnetic resonance imaging study the wrists with a type I lunate did not have contact between the lunate and hamate in any position; the wrists with a type II lunate did have contact between the hamate and the lunate, but only in ulnar deviation. The results of this study demonstrate that the kinematics of a type I lunate are different from those of a type II lunate during radial-ulnar deviation of the wrist.     

The pathology of the long ulna: anatomy and treatment

A long ulna, as a result of congenital differential growth, such as Madelung's disease, or injury, commonly a consequence of a malunited distal radial fracture, may present clinically as pain, decreased motion, mainly of pronosupination, and weakness of grip. Secondary effects may include perforations and tears of the triangular fibrocartilage complex, cartilage wear of the proximal surface of lunate and triquetrum and tears of the lunotriquetral ligament. Positive ulnar variance may be evident on X-rays but a prominent ulnar head cannot always be excluded when there is neutral ulnar variance and further investigations, such as an arthroCTscan or arthroscopy, may be necessary. The two principle treatment options are (a) resection of the distal ulna (Darrach's and Sauvé-Kapandji's techniques are commonly used) and (b) techniques preserving the ulnar head, including different modalities of shortening osteotomy. The aim is to regain a congruent distal radioulnar joint, restore painless and normal pronosupination and prevent onset of osteoarthritis of this joint.     

Dynamic changes in the shape of the triangular fibrocartilage complex during rotation demonstrated with high resolution magnetic resonance imaging.

We studied in vivo dynamic changes in the triangular fibrocartilage complex (TFCC) in ten healthy volunteers using high-resolution magnetic resonance imaging (MRI). A custom made surface coil, which was specially designed to allow movements of the wrist in all directions, was used in this study. MR images in the axial and coronal planes were acquired at maximum pronation, in the neutral position and at maximum supination. During pronation and supination, little deformity of the disc proper was seen on axial sections. In contrast, the ulnar side of the TFCC around the ulnar styloid process showed obvious dynamic changes. The ulnar head translated palmarly to the radius in supination and dorsally in pronation, while there was little change in the position of the fovea of the ulna in relation to the radius. Considering the three-dimensional structure of the TFCC, these findings suggest that the disc proper is strong enough to support the ulnar carpus with little deformity during rotation and that the triangular ligament twists at its origin. During rotation there is friction between the proximal side of the disc proper and the ulnar head. On coronal sections, the disc proper became thinner in pronation due to increased ulnar variance.     

Surgical technique of a radial wedge "camembert" osteotomy in Kienböck disease

The main accepted principle to treat Kienb?ck disease is to decompress the lunate. Radius shortening is the most used technique. Three transverse osteotomies of the radius are described: neutral shortening osteotomy, lateral closing wedge osteotomy, and medial closing wedge osteotomy. Shortening the radius decompress the lunate and more or less the scaphoid. This deviates axial constraints toward ulna and triangular fibrocartilage complex. But the ulnar wrist is not able to support important axial constraints. The authors propose a solution to decompress only the lunate and not the scaphoid. This solution deviates axial constraints toward the scaphoid, which is naturally the most capable bone to support it. The authors describe a new radial nontransverse decompression wedge osteotomy. It allows to shorten the radius in front of the lunate. The fixation is done with a dorsal staple. To complete lunate decompression, authors propose to associate a metaphysal ulnar oblique shortening, essentially if ulnar variance is neutral or positive. The preliminar results on 10 cases are presented.     

Relationship between joint laxity and radio-ulno-carpal joint morphology

The relationships between wrist laxity, ulnar variance, sigmoid notch inclination, and lunotriquetral motion were analysed in 60 normal volunteers. A strong correlation between ulnar length and sigmoid notch inclination was found for the entire group. Joint laxity was found to correlate with ulnar variance and lunotriquetral mobility in women, but not in men. The greater the laxity, the shorter the ulna and the greater the lunotriquetral motion during radial to ulnar deviation. These results support the concept that laxity increases the vulnerability of the wrist to injury.     

Anatomic and biomechanical analysis of the arthroscopic wafer procedure.

The ulnar impaction syndrome is a common clinical entity that is most often associated with positive ulnar variance and is characterized by triangular fibrocartilage complex (TFCC), lunate, and/or distal ulnar pathology. Traditional treatment for symptomatic ulnar impaction syndrome has been conservative; however, in cases refractory to nonoperative management, formal ulnar shortening has been successful in long-term clinical series. Recently, arthroscopic ulnar shortening, the "arthroscopic wafer procedure" (AWP) (debridement of the perforated TFCC margins and limited ulnar head resection using a motorized burr) has become an option to treat this clinical syndrome. In an attempt to evaluate the biomechanical efficacy of the AWP, an experimental study was undertaken using nine ulnar positive cadaver forearms. Each specimen was evaluated biomechanically using axial load cells and pressure-sensitive film to evaluate the effect of serial resection of the TFCC and distal ulna on axial load and ulnar carpal pressures. The results of this experimental study revealed a statistically significant unloading of the ulnar aspect of the wrist after excision of the centrum of the TFCC and resection of the radial two-thirds width of the ulnar head, to a depth of subchondral bone resection. Furthermore, additional bony resection tended to correlate favorably with the stage of TFCC pathology noted, i.e., the more advanced the stage, the more resection necessary to unload the ulnar aspect of the wrist. Based on this biomechanical study, a limited clinical series has been initiated with early favorable results. The AWP biomechanically unloads the ulnar carpal complex, and therefore has a theoretical potential of relieving the symptoms of the ulnar impaction syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)