Anatomic variations in radial and ulnar lengths in the wrists of Chinese

Kienböck Disease: Recent Advances in Understanding and Management

➢ An at-risk lunate (due to anatomic factors) subjected to a trigger event (axial load, embolism, hypercoagulability) leads to the development of lunate osteonecrosis.➢ Children, adolescents, and elderly patients with Kienböck disease respond well to nonoperative treatments, and this should be considered before any surgical intervention.➢ For disease limited to the lunate, treatment decisions should be driven by the condition of the cartilage; intact lunate cartilage can be treated with joint leveling or core decompression, whereas disrupted cartilage surfaces should be bypassed with scaphocapitate or scaphotrapeziotrapezoid arthrodesis. Newer surgical procedures such as wrist arthroscopy and the introduction of contrast-enhanced magnetic resonance imaging have expanded the treatment options for these patients.➢ Once disease extends outside of the lunate, reconstruction with proximal row carpectomy or partial or total wrist arthrodesis should be considered on the basis of which articular surfaces are affected.➢ The new unified classification system and treatment are applicable to almost all patients with Kienböck disease.

Morphometric Analysis of Ulnar Variance and Its Demographic Dynamics Using High Resolution MRI: A Retrospective Study in Indian Population and Review of Literature

Background

Ulnar variance (UV) is the variation of the level of the distal articulating surface of the radius with respect to the distal articulating surface of the ulna. These variations either positive or negative can predispose to pathologies involving the wrist joint. The aim of this study was to measure the ulnar variance in a subset of Indian population using high-resolution MRI and compare our results with the existing literature.

Materials and Methods

Retrospective analysis of 100 normal wrist MRIs were done performed during November 2020 to November 2021 and the ulnar variance was calculated using the Method of Perpendiculars. All the MRI sequences were performed by an experienced radiologist with prior fixed protocol for the study. The measurements were done on the mid-coronal section based on the Method of Perpendiculars using Meddiff Rispacs software.

Results

The average age of the participants was 42 years, with Male to female ratio of 0.9:1. 47 MRIs were of the left wrist, while 53 MRIs were of the right wrist. The mean UV was - 0.7 mm (SD-0.175), ranging from - 4.5 mm to 3.5 mm. There was a significant relationship between ulnar-variance and age, as ulnar-variance increases with the age (p value = 0.039). There was no statistically significant correlation of ulnar-variance with gender distribution and handedness.

Conclusions

This study utilized high-resolution MRI for measuring ulnar-variance in a subset of Indian population and disclosed that the ulnar-variance affirms a positive correlation with age, while no specific pattern between the ulnar-variance and gender or handedness could be established.

Graphical abstract

Radiological characteristics of Kienböck's disease in the Korean population

PURPOSE

In Kienböck's disease, the wrist displays certain characteristic radiological parameters, which have been reported to differ among countries. In the present study, we aimed to identify specific radiological parameters of the unaffected wrists in patients with unilateral Kienböck's disease and to determine the extent of the association of each parameter with the disease in Korea.

METHODS

This retrospective case-control study assessed the radiological parameters of patients with Kienböck's disease ( n = 53) and controls ( n = 53), who visited our institution between January 2000 and May 2013. Ulnar variance (UV), radial inclination, lunate fossa inclination, lunate diameter, lunate height, lunate tilting angle (LTA), lunate covering index (LCI), and Ståhl index (SI) were measured and analyzed using a binary logistic regression model.

RESULTS

We observed that wrists with a high LTA and LCI, and low UV and SI had a tendency to develop Kienböck's disease.

CONCLUSION

In the Korean population, a high LTA and LCI, and low UV and SI of the unaffected wrists on plain radiography might be associated with Kienböck's disease. The radiographic characteristics of the unaffected wrists can differ between patients with unilateral Kienböck's disease and normal individuals.

Negative Ulnar Variance and Kienböck Disease

PURPOSE

To test the primary null hypothesis that there is no difference in mean ulnar variance (UV) scaled to the length of the capitates between 166 wrists with Kienböck disease and an equal number of matched controls and to test the secondary null hypothesis that mean scaled UV does not vary based on age, sex, or race in both Kienböck and control wrists.

METHODS

Ulnar variance was measured on posteroanterior radiographs of the wrist as the distance between a line through the midpoint between the volar and the dorsal edges of the ulnar margin of the radius and a line tangential to the most distal aspect of the carpal surface of the head of the ulna, both perpendicular to the longitudinal axis of the radius. Measurement of UV was scaled to the length of the capitate, resulting in a UV to capitate height (UV:CH) ratio.

RESULTS

We found a significant difference in mean UV:CH ratio between patients with Kienböck disease and a control group matched by age, sex, race, and limb. The prevalence of negative UV was high in both patients with Kienböck disease and matched controls. There were no differences in mean UV:CH ratio with respect to age, sex, or race among patients with Kienböck disease or matched controls.

CONCLUSIONS

The precise role of ulna minus in the development of Kienböck disease remains uncertain and unanswered, given that many patients with Kienböck disease have neutral or positive UV. In addition, a large proportion of the normal population has negative UV, whereas Kienböck disease is rare.

Measurement of Ulnar Variance in a Regional Subset of Indian Population-A Pilot Study of 30 Subjects

BACKGROUND

The variation of level of distal articulating surface of ulna with respect to distal articulating surface of radius is known as ulnar variance (UV). Positive and negative UV has been implicated in various wrist and hand pathologies.

AIM

To measure ulnar variance in a regional subset of Indian population and to compare two techniques of measurement of ulnar variance viz. method of perpendiculars and modification of the concentric circles method.

MATERIALS AND METHODS

UV was measured in a regional subset of Indian population comprising of 30 subjects. The mean age of patients was 35.9 years. There were 16 males and 14 females in the study group. Antero-posterior (AP) X-rays of wrist in neutral position were taken and UV was measured using method of perpendiculars and the modified circle method.

RESULTS

The mean UV using method of perpendiculars (UVA) was 0.387 mm and using modified circle method (UVB) was 0.507mm. A higher predominance of positive UV in this regional subset of Indian population was observed. There was no correlation between UV with respect to age and sex. No statistically significant difference was observed between the two methods of measurement utilized in the study.

CONCLUSION

The documentation of a negative and positive ulnar variance will help in prophylactic and timely intervention for various wrist pathologies, if required. However, a larger sample size with a longer follow up is required to suggest a correlation of ulnar variance with clinically symptomatic disease.

Epidemiology of Kienböck's disease in middle-aged and elderly Japanese women

Little research has been done on the prevalence of Kienböck's disease, and there is no consensus on the relationship between Kienböck's disease and negative ulnar variance. The goal of this cross-sectional study was to determine the prevalence of Kienböck's disease in middle-aged and elderly Japanese women and to clarify the relationship between Kienböck's disease and negative ulnar variance. The authors analyzed plain radiographs of both hands in women 40 years and older residing in the community to investigate the prevalence of Kienböck's disease and the relationship between Kienböck's disease and negative ulnar variance. Kienböck's disease was seen in 7 of the 572 participants. In the group with Kienböck's disease, ulnar variance did not differ significantly between affected (0.3 mm; SD, 1.5) and unaffected (0.3 mm; SD, 1.0; P=.285) sides. No significant difference was seen in ulnar variance values between the affected side in the group with Kienböck's disease and the normal group (P=.118). The number or proportion of participants with negative ulnar variance did not differ significantly between the affected side in the group with Kienböck's disease (3 of 7) and the unaffected side in the group with Kienböck's disease (1 of 7; P=.237) and between the affected side in the group with Kienböck's disease and the normal group (111 of 504; P=.189) by chi-square test. The prevalence of Kienböck's disease was 1.2% in middle-aged and elderly Japanese women. Negative ulnar variance is not a contributing factor to Kienböck's disease.

Radial shortening osteotomy for Kienböck disease: minimum 10-year follow-up

PURPOSE

To clarify long-term clinical and radiological results more than 10 years after radial shortening osteotomy for Kienböck disease.

METHODS

Eleven wrists of 10 patients that had been classified as Lichtman stages 3A (2 wrists), 3B (8 wrists), and 4 (1 wrist) underwent radial shortening for Kienböck disease. The mean follow-up period was 14.3 years (range, 10-21 y). Clinical outcomes were quantified using the Japanese version of the Disabilities of the Arm, Shoulder, and Hand questionnaire and the modified Mayo wrist score. Radiographic and magnetic resonance imaging studies were performed for 9 of the 10 patients preoperatively and all 10 patients at follow-up.

RESULTS

At follow-up, 6 wrists were asymptomatic and the remaining 5 had mild occasional pain. The mean range of extension and grip strength significantly improved. The mean modified Mayo wrist score and Disabilities of the Arm, Shoulder, and Hand scores were 92 (range, 80-100) and 5 (range, 0-18), respectively. At follow-up, no progression of the Lichtman stage was found in any patient. There was no significant progressive lunate collapse in any patient. The magnetic resonance imaging in 7 wrists showed increased signal intensity of the lunate; the remaining 3 wrists had no alteration in signal intensity of the bone.

CONCLUSIONS

Our study demonstrated satisfactory clinical results after 10 or more years in patients who underwent radial shortening for Kienböck disease. Although we found no improvement in signal intensity of the lunate in 3 wrists, unloading of the diseased lunate after radial shortening gives long-lasting symptom relief and may prevent lunate collapse.

TYPE OF STUDY/LEVEL OF DISEASE

Therapeutic IV.

The association of Kienbock's disease and ulnar variance in the Iranian population

We retrospectively determined the distribution of ulnar variance in 60 patients with Kienböck's disease. We also measured the ulnar variances in 400 standard wrist radiographs in the normal adult population. The mean ulnar variance of the Kienböck's group was -1.1 mm (SD 1.7) and the mean ulnar variance of the general population was +0.7 (SD 1.5), which was significantly different. In the Kienböck's disease group there were 38 (63%) with ulnar negative, 16 (27%) neutral and six (10%) with ulnar positive variance. The preponderance of ulnar negative variance was statistically significant. There was an association between ulnar negative variance and the development of Kienböck's disease in this study.

Osteotomy of the radius without shortening for Kienböck disease: a 10-year follow-up

PURPOSE

To determine the long-term effect of distal radius osteotomy without modifying the radial length or inclination for Kienböck disease.

METHODS

Over 9 years, 14 patients underwent osteotomy of the distal radius without altering radial length or inclination. A total of 11 of these patients were available for follow-up after 10 or more years. We assessed pain, range of wrist motion, and grip strength preoperatively and postoperatively in all cases, as well as preoperative and postoperative posteroanterior and lateral x-rays.

RESULTS

The osteotomy healed in all cases. All 11 patients had decreased pain and showed improvement in wrist motion and grip strength. Radiographically, there were no measurable changes in ulnar variance and there was minimal loss of carpal height. In some patients, the lunate showed increased sclerosis or fragmentation.

CONCLUSIONS

An osteotomy of the distal radius without altering radial length or inclination was effective in decreasing pain and improving grip strength and wrist motion regardless of ulnar variance.

Radial overgrowth after radial shortening osteotomies for skeletally immature patients with Kienböck's disease

PURPOSE

We hypothesized that radial shortening osteotomy (radial shortening) for skeletally immature patients with Kienböck's disease would induce overgrowth of the radius. The purpose of this study was to determine the effect of radial shortening on radial growth in skeletally immature patients with Kienböck's disease and to clarify the relationship between the postoperative growth alterations and the clinical results.

METHODS

Eight wrists of 8 skeletally immature patients with Kienböck's disease were treated with radial shortening. There were 3 boys and 5 girls, ranging in age from 11 to 18 (mean, 14) years old. All patients presented with open physis and negative ulnar variance. The length of the radial shortening equaled the amount of negative ulnar variance. Clinical assessment was based on the modified Nakamura scoring system. Radiographic assessment, including Lichtman's stages, ulnar variance, carpal height ratio, radial inclination, and volar tilt, was performed before surgery, immediately after surgery, and at follow-up. A difference in ulnar variance of more than 2 mm between these 3 measurements was considered to be overgrowth. Statistical comparisons were performed using paired t-tests.

RESULTS

At a mean follow-up period of 69 months, the mean clinical score was 19.7 of 21 maximum points, with all wrists rated as excellent. Radiographically, no progression of Lichtman stage was found in any patient. At follow-up, the x-ray and magnetic resonance imaging findings indicated lunate revascularization in all patients. Four of the 8 had overgrowth in the operated radius. On the other hand, other radiographic parameters showed no significant changes at follow-up. The occurrence of postoperative radial overgrowth did not notably affect the clinical scores.

CONCLUSIONS

The current results suggest the probability of overgrowth of the radius in skeletally immature patients with Kienböck's disease treated with radial shortening. The postoperative radial overgrowth after this osteotomy had no effect on clinical and other radiographic outcomes.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

The incidence of asymptomatic Kienböck's disease

The aim of this study was to determine the incidence of asymptomatic Kienböck's disease in patients who attended the Dr George Mukhari Hospital (formerly Ga-Rankuwa Hospital), as well as the relevance of ulnar variance on the disease. This was a retrospective study. In a 12 month period we reviewed postero-anterior radiographs of 1287 patients seen at our radiology department, with complaints unrelated to the upper limb including the wrist and hand. We identified 23 cases (1.9%) of asymptomatic Lichtman stage II-IV Kienböck's disease in our African population. The majority (63%) were male with an average age of 49 years, and 37% were female with an average age of 46.5 years. All cases were unilateral and all were in the dominant hand. Thirteen cases (57%) had an ulnar neutral wrist and the remaining ten (43%) had an ulnar negative variance. The vast majority (83%) were unemployed. Analysis of the data shed no further light on the aetiology. The relevance of ulnar variance as an aetiological factor is questioned.

Ageing does not affect ulnar variance: an investigation in Taiwan

This paper presents a longitudinal study of the effect of ageing on ulnar variance. Between 1976 and 1985, ulnar variance in 1000 normal adult subjects was measured using the Palmer method. In 1995 to 2002, 17 to 22 years later, the ulnar variance was measured again in 864 of them. They were stratified into three age groups: Group I consisted of 351 subjects of young age (20-39 year-old), Group II of 318 subjects of middle age (40-59 year-old) and group III of 195 subjects of old age (60 year-old or older). The means of the initial and the final ulnar variance of the whole series and the three groups were compared by the paired Student's t-test. There were no significant differences between the initial and final ulnar variances in all three age groups and in the whole series. In normal subjects without diseases or injuries affecting the wrist, ageing does not affect the ulnar variance.

Kienböck’s disease

Kienböck’s disease is a form of osteonecrosis affecting the lunate. Its aetiology remains unknown. Morphological variations, such as negative ulnar variance, high uncovering of the lunate, abnormal radial inclination and/or a trapezoidal shape of the lunate and the particular pattern of its vascularity may be predisposing factors. A history of trauma is common. The diagnosis is made on plain radiographs, but MRI can be helpful early in the disease. A CT scan is useful to demonstrate fracture or fragmentation of the lunate. Lichtman classified Kienböck disease into five stages. The natural history of the condition is not well known, and the symptoms do not correlate well with the changes in shape of the lunate and the degree of carpal collapse. There is no strong evidence to support any particular form of treatment. Many patients are improved by temporary immobilisation of the wrist, which does not stop the progression of carpal collapse. Radial shortening may be the treatment of choice in young symptomatic patients presenting with stages I to III-A of Kienböck’s disease and negative ulnar variance. Many other forms of surgical treatment have been described.

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.

Ulnar variance and the role of joint levelling procedure for Kienböck's disease

Forty patients with Kienböck's disease were reviewed to determine the relationship between ulnar variance and the development of Kienböck's disease in a Japanese cohort. The joint levelling procedures designed to correct ulnar variance were evaluated in 11 patients after a mean of 9.7 years following surgery. The mean ulnar variance was 0.50+/-1.67 in patients with Kienböck's disease and 0.56+/-1.76 in a control group. The onset of wrist symptoms in a younger age group was noticed after sports injuries, whereas older patients had no distinct history of trauma. Joint levelling procedures produced good clinical results, but carpal height ratio, Stahl's index and radioscaphoid angle were not improved, as evidenced radiographically. Our study suggests that in a Japanese cohort ulnar minus variance is not an important factor in the aetiology of Kienböck's disease. Although joint levelling procedures improved the clinical results, they did not reverse lunate collapse or carpal alignment.

Physeal fractures of the distal radius and ulna: long-term prognosis

OBJECTIVES

The long-term prognosis of injuries to the distal physis of forearm bones, including complications such as radioulnar length discrepancy and styloid nonunion, has not been extensively studied. Reliable radiographic prognostic criteria to predict physeal disturbance at trauma are also lacking. The aim of this study is to investigate both issues.

DESIGN

Retrospective study.

SETTING

University hospital.

PATIENTS/PARTICIPANTS

One hundred sixty-three lesions to the distal physis of the forearm bones in 157 patients were available for a long-term follow-up. Seventy-seven injuries of the distal radial physis were radiographically isolated, 54 were associated with a fracture of the ulnar styloid, and 26 with a fracture of the distal ulnar metaphysis. Of the six injuries of the distal ulnar physis, five were associated with a fracture of the distal radial metaphysis, and one was an isolated injury of the distal ulnar physis.

INTERVENTION

Treatment consisted of wrist immobilization in a long-arm plaster cast for 6 weeks. Dorsal or volar displacement was reduced using general anesthesia.

MAIN OUTCOME MEASUREMENTS

All patients had both clinical and radiographic evaluation, with an average follow-up of 25.5 years (range 14-46 years). The average age of the patients at injury was 11.6 years (range 5-17 years), whereas their average age at follow-up was 35.5 years (range 22-56 years). Both the Salter and Harris and the Ogden classifications were used to classify physeal injuries.

RESULTS

According to Salter and Harris, of the 157 radial lesions, 18 were type 1 and 139 type 2. According to Ogden, 14 were type 1A, 4 type 1C, 84 type 2A, 13 type 2B, 17 type 2C, and 25 type 2D. Of the 6 ulnar lesions, 2 were Salter and Harris type 1 (Ogden type 1A), 3 type 2 (Ogden type 2A), and 1 type 4 (Ogden type 4A). Fifty-four radiographically evident fractures of the ulnar styloid associated with injuries of the distal radial physis were classified as Ogden type 7A. At follow-up, all of our patients were fully asymptomatic, except for those who had forearm bone growth failure of more than 1 cm. Shortening of the previously injured forearm bones ranging from 1 to 6.5 cm was observed in 2 open and subsequently infected lesions as well as in 5 uncomplicated lesions of the 157 distal radial physeal injuries (4.4%), and in 3 of the 6 distal ulnar physeal injuries (50%). Shortening of 1 cm or more was observed in the uncomplicated lesions of radial physeal injury with Ogden type 1C, 2B, and 2D lesions, and in ulnar physeal injuries Ogden type 1A, 2A, and 4A. Thirty-eight additional patients had radioulnar length discrepancy that ranged from 2 to 9 mm, and 53 patients had styloid nonunion, but all of them were asymptomatic.

CONCLUSIONS

None of the patients reviewed at follow-up, including those with radioulnar length discrepancy of less than 1 cm and those with styloid nonunion, complained of any symptom related to their previous injury, not even those engaged in heavy manual labor. Of the 10 patients with either radial or ulnar shortening of more than 1 cm, only 2 with radial growth arrest and marked radioulnar length discrepancy had severe functional problems. Growth disturbances of more than 1 cm following distal radial physeal injury occurred only in Ogden type 1C, 2B, and 2D lesions, whereas in distal ulnar physeal injuries, growth disturbances occurred regardless of the Ogden classification type.

Treatment of Kienbock's disease with capitohamate arthrodesis: pain relief with minimal morbidity

Despite the large number of procedures available for treatment of Kienbock's disease, no single method has emerged as being clearly superior. Ultimately, the goal of treatment must be the relief of pain and maintaining wrist range of motion. The authors' experience with 45 consecutive wrists that had undergone capitohamate fusion for treatment of Lichtman's stage 1, 2, or 3 Kienbock's disease is presented. Average follow-up was 32 months (range, 4 to 107 months). All arthrodeses healed with an average time to fusion of 1.9 months. Postoperatively, 93 percent of patients had either no pain or less pain than they had preoperatively, with preservation of wrist range of motion and improved grip strength (52 percent of normal preoperatively to 72 percent of normal postoperatively). The authors conclude that capitohamate arthrodesis relieves pain in 93 percent of patients with stage 1, 2, or 3 Kienbock's disease and is an effective treatment for this disease.

Is negative ulnar variance a risk factor for Kienböck's disease? A meta-analysis

Current treatment for Kienbock's disease using joint-leveling procedures is based on the hypothesis that the disease is caused by negative ulnar variance. The authors conducted a meta-analysis to evaluate this hypothesis, and assessed the quality of available published studies. They searched MEDLINE to collect literature that evaluated this association. Only 3 of 18 collected studies had sufficient data or study design to meet their inclusion criteria. A summary odds ratio (OR) calculated using a conservative random-effect method showed that the odds of Kienböck's disease was 3.10 times more likely for those with negative ulnar variance than those with positive or neutral ulnar variance, but this was not significant (95% confidence interval, 0.95-10.05; p = 0.06). The combined OR was unstable because of marked heterogeneity across the studies. This meta-analysis reveals that there is insufficient data to support a significant (p < 0.05) association between negative ulnar variance and Kienbock's disease.

Lunate Morphology of Kienböck's Disease on X-Ray Study

To investigate whether the lunate morphology proposed by Watson predisposes to Kienböck's disease, we investigated 23 patients with Kienböck's disease and 24 normal controls. Lateral X-ray films showed 17 of type D (dorsally lower height) lunate; 2 of type P (palmary lower height); and 1 of type N (equal palmar height to dorsal). In the control group, there were 21 of type D; 2 of type P; and 1 of type N, among 24 patients. The mean wedge ratio was 1.17 (1.08-1.35) in type D of the Kienböck group, and 1.11 (1.03-1.41) in type D of the control group. There were no statistically significant differences between the two groups, and palmar and dorsal lunate morphology is not believed to predispose to Kienböck's disease.

Kienböck disease and negative ulnar variance

We compared the degree of ulnar variance, measured on standardized radiographs of the wrist, in forty-four patients who had Kienböck disease with that in ninety-nine control subjects who had been selected from a general clinic population and had radiographs of the wrist. The purpose of our study was to determine if there is a true relationship between negative ulnar variance and the development of Kienböck disease. Gender was not found to influence the degree of ulnar variance, but an association was found between age and negative ulnar variance in both the control subjects and the patients who had Kienböck disease. The findings of the present study confirmed an association between negative ulnar variance and the development of Kienböck disease even after correction for the influence of age on the measurement of ulnar variance.

[Long-term results of 9 cases of elongation of the ulna in treatment of Kienböck's disease]

The treatment of Kienböck's disease is currently controversial. Ulnar shortness is usually considered to be the main etiological factor. This observation is the basis for distal radio-ulnar joint levelling procedures, which means the radial shortening osteotomy and ulnar lengthening osteotomy. Several authors have reported their experience on the topic, but there are very few studies with sufficient follow-up to evaluate the value of the operative procedure on the carpus. We report a 9 patient review series following an ulnar lengthening procedure for Kienböck's disease. The average follow-up was 24 years (range: 12 to 21 years). There were 7 men and 2 women and the average age was 30 years at the time of the operation. The dominant side was affected 6 times out of 9.6 heavy workers and 3 light workers are reported. Four out of 9 patients had a history of trauma. The surgical procedure was a stair-step distal diaphyseal ulnar lengthening with distraction and osteosynthesis with a plate, without bone graft. The selected patients underwent a clinical examination of wrist pain, mobility and strength in comparison with the non-operated side. All patients under went a standard radiographical examination in neutral position. The analysis of the series shows that ulnar lengthening was successful for all patients especially on the strength and pain level, whereas mobility deteriorated. Without being able to reconstitute the normal morphology of the lunate bone, the procedure was able to stop the long-term natural course of the disease leading to carpus collapse and arthrosis without radio-carpal disturbance. Excessively long consolidation times and a very high pseudarthrosis rate are reported. Ulnar shortness does not seem to be an etiological factor. The natural history of the disease is perhaps not as bad as previously thought. The impact of the procedure on the distal radio-ulnar joint and the ulnar impaction syndrome in excessive lengthening are serious issues which need to be resolved. The procedure is preferably indicated in young patients, at the beginning of the disease, with a negative distal radio-ulnar variance. The Linscheid operative technique is recommended.

Histologic analysis of fetal ulnar variance

Twenty-eight fetal wrists aged 5 to 21 weeks gestation were examined histologically to assess ulnar variance. There was a trend from ulna negative to ulna neutral among this population. Of 10 wrists in group I (5-8 weeks gestation), 8 were ulna negative and 2 were ulna neutral. Of nine wrists in group II (11-13 weeks gestation), three were ulna negative and six were ulna neutral. Of nine wrists in group III (18-21 weeks gestation), two were ulna negative and seven were ulna neutral. Overall, 13 embryos demonstrated an ulna negative variance; the remainder had ulna neutral variance. These results are significantly different than the incidence of ulnar variance in adults. With growth, factors must occur that change this fetal relationship of radius to ulna.

Does the normal contralateral wrist provide the best reference for X-ray film measurements of the pathologic wrist?

This study compares in normal subjects the variability of wrist x-ray film measurements between the right and left sides with the variability of the distribution of those measurements within the population. Additional purposes were to evaluate possible differences of these measurements according to sex, age, side, and hand dominance. The variability when comparing both sides was found to be statistically less for the carpal height, radiolunate, scapholunate, and capitolunate angles than within the whole group of subjects, and for those measurements, there was a high correlation (r > .88) between the right and left sides. In addition, the carpal height and the carporadial ratios were lower and the capitolunate angle was higher in women than in men. There was also a significant decrease of the scapholunate angle in older individuals. The clinical implication of these findings is that in unilateral wrist diseases, the normal wrist should be used to provide the reference values of the carpal height and of the carpal angles on profile x-ray films. However, for the radial inclination and palmar tilt of the distal radius and for the ulnar variance, the normal side does not provide a better reference than normal values obtained from databases.

Negative ulnar variance is not a risk factor for Kienböck's disease

Ulnar variance was measured in standardized conditions in 125 normal wrists and in 52 patients with Kienböck's disease. No significant difference in ulnar variance between a sex/age-matched control group and a group of patients affected with Kienböck's disease was found. A positive correlation was found between age and ulnar variance. No significant difference was found between men and women. Based on these results, negative ulnar variance does not seem to be an important factor in the etiology of Kienböck's disease.

Anatomical risk factors for Kienböck's disease

Contralateral unaffected wrists from 41 males with Kienböck's disease were compared with wrists from 66 normal males. From X-rays, various features of the lunate and radius were measured. In patients with Kienböck's disease, the lunate tended to be smaller and inclined more radially than in normal subjects and the radial inclination was flatter. Discriminant analysis showed that 85% of the unaffected contralateral wrists in patients with Kienböck's disease and 74% of the wrists in normal subjects were accurately discriminated to their respective groups. It may be possible to identify subjects who are at risk for Kienböck's disease prior to onset using discriminant analysis.

Strain-gauge evaluation of lunate unloading procedures

A biomechanical study was undertaken to determine which procedure(s) most effectively relieve load from the lunate. Strain gauges were mounted on the lunates of 20 preserved cadaveric limbs. Three types of procedures were performed: scaphotrapeziotrapezoid arthrodesis, capitohamate arthrodesis, and ulnar lengthening. Load testing was performed both before and after the simulated fusions and ulnar lengthenings. Ulnar lengthening of 3 mm was the most effective method of lunate strain reduction. Capitohamate arthrodesis decreased compressive strain but increased shear strain. Scaphotrapeziotrapezoid fusion significantly increased both compressive and shear strain in the lunate. Of the three procedures that were tested, ulnar lengthening to create a neutral variance is the most reliable means of unloading the lunate.

The influence of age and sex on ulnar variance

Ulnar variance was measured in 325 normal wrists and 41 wrists with Kienböck's disease. A positive correlation between ulnar variance and age was confirmed in normal wrists, and it was lower in males than in females. Therefore, studies comparing ulnar variance in abnormal and normal wrists require carefully selected age- and sex-matched controls. There was no significant difference in ulnar variance between Japanese with normal wrists and those affected by Kienböck's disease, when the effects of sex and age were taken into account. Based on these results, we believe that ulnar variance is highly unlikely to be an important predisposing factor in Kienböck's disease.

Measuring ulnar variance: a comparison of techniques

This study compared three commonly used methods of measuring ulnar variance. The comparison included the project- a-line technique (A), the method of concentric circles (B), and the method of perpendiculars (C). Specific features studied were variations in results generated by each technique as well as the interobserver and intraobserver reliability for each technique. The only significant difference among techniques was between techniques A and B (p = 0.0224), where mean A values were more positive than mean B values. Observers were found to differ significantly (p = 0.0092) independent of technique. All methods studied were highly reliable, although the method of perpendiculars was most reliable for both interobserver (reliability = 0.9801) and intraobserver (reliability = 0.9719) reliability. This study shows that the clinician may choose whichever technique he prefers when measuring ulnar variance.

Correlation of clinical and radiographic findings in Kienböck's disease

Radiographic and clinical findings were reviewed in 50 patients with Kienböck's disease. In 40 patients the clinical and radiographic findings were complete enough to allow correlation of findings. Measurements were made from radiographs in an attempt to quantify the anatomic substrate of Kienböck's disease and to determine which radiographic measurements might be helpful in predicting the course and prognosis of the disease. The measurements included ulnar variance, radial slope, carpal index, carpal angle, combined cortical thickness, optical density, radial slant, scapho-lunate angle, lunate deformation quotient, and the radiographic stages modified from Stahl. These measurements were correlated with patient's history, age at onset of disease, range of motion, and grip strength. Relevant anatomic factors were ulnar variance and the radial slope. The best radiographic features for correlation with loss of motion and grip strength were the lunate deformation quotient and, to a lesser extent, the carpal index. None of the radiographic measurements were very strongly correlated with the clinical findings.

Radiologic examination and measurement of the wrist and distal radio-ulnar joint. New aspects

Following fractures of the distal radius, a relatively high incidence of complications is caused by malalignment in the distal radio-ulnar (DRU) joint; recent anatomic and clinical investigations have shown congruity of that joint to be of significant importance for restoring the function of the wrist. The radius forms a moderately arched bone, which moves around the ulna in pronation and supination. Biomechanically, the ulna may be regarded as the pillar around which the radius moves. In an anatomic investigation of 5 arm specimens, we have shown that the maximum cartilage contact in the DRU joint between the ulnar head and the distal radius occurs in the neutral rotation position. A proposed routine examination method of the wrist and forearm includes a true antero-posterior and a lateral projection of the radius and the ulna, performed with the forearm and wrist in a neutral rotation, a neutral wrist deviation and with the elbow angled 90 degrees. Such an examination implies a standardized and reproducible method. In a radioanatomic investigation, a series of 50 healthy wrists and forearms were examined. A simple measuring technique is presented, applicable to the DRU joint and wrist favouring the ulna as the bone through which a reproducible long axis of the forearm/wrist may be drawn. It is suggested that the length of the radius should be judged relative to the ulna. Ulnar head inclination and radio-ulnar angle are new concepts, being major characteristics of the DRU joint. These angles of the right and left wrist were equal and no difference was found between the sexes. Minor alterations of the distal radius may be revealed when estimating these angles.

Ulnar variance determination

Surgical procedures concerning the distal articular surfaces of the radius and ulna, demand an accurate method of measurement of ulnar variance. A new method, which is a modification of the method described by Palmer (1982), is introduced. 100 randomly selected healthy persons were submitted to X-ray of the wrist and the ulnar variance was determined independently by three observers using both methods. By "weighted kappa" statistics the results, expressed in intra- and interobserver agreement, showed a significantly higher reliability in favour of the Modified method.

Carpal ligamentous disruptions and negative ulnar variance

Negative ulnar variance is a condition in which the ulna is relatively shorter than the radius at the carpus. It was found in 21% of 203 normal wrists. We have observed an increased incidence (49%) of this anomaly in patients with carpal ligamentous instabilities (dorsiflexion instability, palmar flexion instability, scapholunate dissociation with rotary luxation of the scaphoid, and lunate and perilunate dislocations). While the reasons for this association have yet to be adequately delineated, the presence of a negative ulnar variant may serve as an impartial clue to the presence of ligamentous instability. Many carpal instabilities present with subtle radiographic findings requiring careful evaluation of radiographs. Patients with negative ulnar variance and histories suggestive of ligamentous instability should undergo careful radiologic evaluation to assure early diagnosis of carpal disruption.

Radiology of postnatal skeletal development. IV. Distal radius and ulna

Thirty-one pairs of distal radioulnar units were obtained from human cadavers ranging in age from full-term neonates to fourteen years. These were studied morphologically and radiographically. Specimen roentgenography using air/cartilage interfacing demonstrated the osseous and cartilaginous portions of the epiphyses. These roentgenographic aspects of development are discussed and illustrated to provide a reference index. The radial and ulnar physeal/metaphyseal contours initially are transverse. Progressively the distal radius develops a proximally directed curve adjacent to the radioulnar joint. Both physes subsequently develop a convex contour with mild undulations, and a central concavity associated with the secondary ossification center. Longitudinal ossification striations were observed crossing the distal ulnar physis. These appear to be normal. At no time during postnatal development did the distal ulna ever articulate directly with the carpus. It was always separated by a segment of triangular fibrocartilage connecting the ulnar styloid to the distal radial epiphysis. This was never perforated. This discoid cartilaginous structure is the anatomic cause of the concomitancy of ulnar styloid fractures with distal radial epiphyseal injuries, an injury pattern which may occur prior to ossification in the ulnar styloid, and which may lead to non-union of the styloid when ossification eventually occurs. In none of the specimens was an accessory ossification center present in either the radial or ulnar styloid process.