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PubMed1992

The distal joint of the radius and ulna. Diagnostic studies and treatment rationale.

Three areas of functional anatomy are present in the distal ulna. Each of these has a specific function in load bearing of the wrist, rotation of the forearm, and maintenance of the relationship between the radius and ulna. The distal portion of the ulna serves as a suspensory post for ligaments that stabilize the ulnar border of the wrist. The midportion of the distal ulna contains the load-bearing triangular fibrocartilage complex. The proximal portion of the distal ulna articulates with the radius at the sigmoid notch and participates in forearm rotation. Each of these areas is assessed in problems related to ligament instability, load bearing, and range of motion. Mechanical problems that affect the distal joint of the radius and ulna include the affects of trauma, degenerative change, and inflammatory disease. Each of these requires evaluation in the treatment of joint derangement. Diagnostic studies that relate to problems in the distal radioulnar joint area include standard roentgenographs, arthrograms, magnetic resonance (MR) scanning, and arthroscopy. Each of these studies has particular advantages and disadvantages in providing data for analysis of joint malfunction. A medical history, physical examination, and use of proper diagnostic studies will assist in an appropriate diagnosis of problems in the distal joint of the radius and ulna.

Adult↗
PubMed1984

[Indications and results in shortening osteotomy of the ulna].

A relatively or absolutely too long ulna leads always to pain in the wrist, so that a compensation in length of both forearmbones is achieved by shortening osteotomy. The gradual ulna shortening osteotomy, the stylectomy and the resection of the caput ulnae with or without radius transposition osteotomy are available as shortening operation. In 17 patients of the Giessener Unfallchirurgischen Klinik we performed in 14 cases a shortening osteotomy of the ulna and in 3 cases a resection of the caput ulnae. The shortening osteotomy lead in all cases to a reduction of complaints and to an improvement of the mobility of the wrist. Due to frequent arthropathy the resection of the caput ulnae should be taken more often into consideration in older people.

Fracture Fixation, Internal↗
PubMed2006

Pattern of osteophytes and enthesophytes in the proximal ulna: an anatomic, paleopathologic, and radiologic study.

OBJECTIVE: To develop a schematic segmentation of the proximal ulna in order to detect, assess the frequency, and characterize the bony outgrowths arising from the trochlea and from the radial notch of the ulna, to enable differentiation of osteophytes from enthesophytes. MATERIALS AND METHODS: Eighty well-preserved ulna specimens from the collection of the San Diego Museum of Man were analyzed by two musculoskeletal radiologists. The trochlea and the radial notch of the ulna simulate the shape of a clock quadrant. The proximal ulna was divided into 24 anatomic areas. The relationships of the joint capsule and insertions of tendons and ligaments onto these area were assessed by the two readers, and the resulting appearances of bony outgrowths were compared at visual inspection and on Radiographs. RESULTS: The interobserver visual comparison was good in 17 areas out of 24, but poor correlation was found in 7 areas. In one case, difficulties in differentiating osteophytes originating from the brachialis muscle/ tendon (area 9) from an enthesophyte originating from the capsule insertion on the coronoid process (areas 2 or 3) occurredand between two different enthesophytes in a further case. Five cases had difficulties in defining differences in the grading system of the outgrowths. The percentage of outgrowths observed in each of the areas was globally high, especially in areas 9 and 10. On radiographs it was possible to observe irregularities in ten areas; in eight at a threshold of height of 2 mm (areas 1-4, 9, 10, 11, 14) and in two at a threshold of height of 3 mm (areas 5, 6). The two readers had the same difficulties in differentiating enthesophytes from osteophytes at radiographic and visual examination. CONCLUSION: Our segmentation scheme is reproducible and objective, and permitted the differentiation of the bony outgrowths arising from the proximal ulna into osteophytes and enthesophytes, which may be particularly useful for the in vivo assessment of abnormalities seen in elbow overuse syndromes.

Humans↗
PubMed2004

Kinematics of the ulna during pronation and supination in a cadaver study: implications for elbow arthroplasty.

OBJECTIVE: Aim of this study was to exactly describe and quantify kinematics of the ulna during pro- and supination. DESIGN: Biomechanical study in fresh frozen cadavers. BACKGROUND: A previous MRI study revealed a varus/valgus motion of the ulna averaging 7.1 degrees during pro-/supination. Axial rotation, however, could not be quantified. METHODS: Sixteen arms were examined in a new apparatus that fixed the humerus on a template and allowed forearm rotation. Motion of a Kirschner wire placed in the ulna was recorded in steps of 30 degrees by two perpendicularly arranged charge coupled device cameras during pro- and supination. RESULTS: From supination to pronation the ulna showed a semi-lunar evasive motion in the coronal and transverse plane with an initial varus shift, then a dorsal and finally a valgus shift. Motion in the coronal plane averaged 14.14 degrees (SD 4.78). Valgus angles of the ulna in 30 degrees, 60 degrees and 90 degrees pronation were significant (P<0.05) to each other and the neutral position. Varus angles of the ulna in 30 degrees, 60 degrees and 90 degrees supination (P<0.01) were significant to each other and the neutral position.A maximum ulnar axial pronation rotation of 3.2 degrees (SD 2 degrees ) was noted. Axial rotation angles of 90 degrees and 60 degrees of pronation were significant to each other and to the neutral position (P<0.05), respectively. CONCLUSIONS: To prevent increased stress on the bone-cement interface in elbow arthroplasty, a mean axial rotation of at least 3.2 degrees should be possible.

Arthroplasty, Replacement↗
PubMed2006

Reconstruction of the interosseous ligament unloads metallic radial head arthroplasty and the distal ulna in cadavers.

PURPOSE: Longitudinal radioulnar dissociation may result when a compressive load to the hand results in excessive proximal migration of the radius with interosseous ligament (IOL) disruption and radial head fracture. Interosseous ligament reconstruction has been proposed to restore more normal forearm mechanics. The objective of this study was to evaluate the effect of IOL reconstruction on compressive load transfer through the forearm after excision and metallic replacement of the radial head in cadavers. METHODS: In 8 cadaveric forearms, 138 N of compressive load was applied to the hand in neutral forearm rotation and neutral elbow varus-valgus alignment. We measured proximal radial migration and 3-dimensional force vectors acting on the distal radius, distal ulna, IOL, proximal radius, and proximal ulna. The experiment was repeated in order for 5 conditions: (1) with the IOL intact, (2) with the IOL reconstructed with a double-bundle flexor carpi radialis construct, (3) with the radial head excised, (4) after metallic radial head arthroplasty, and (5) after cutting the IOL reconstruction. Analysis of variance was used for statistical comparisons. RESULTS: With the IOL intact the resultant load in the distal radius was 94% +/- 3% of hand load, with 75% +/- 2% transmitted to the proximal radius. Double-bundle flexor carpi radialis reconstruction effectively restored this relationship. After radial head excision the resultant distal radius load decreased whereas great increases were seen in the resultant distal ulna load, the resultant load in the IOL reconstruction, the resultant load in the proximal ulna, and proximal radial migration. Force continued to transfer through the proximal radius transversely, with a 400% increase in transverse force, a consequence of abutment of the radial stump caused by proximal radioulnar convergence (there was no contact at the capitellum). After radial head arthroplasty loads transferred across the wrist remained closer to intact but the resultant load on the distal ulna and proximal radius remained increased. With cutting of the IOL reconstruction transverse forces in the forearm became negligible, the resultant distal ulna load increased by 50%, and the resultant radial head load increased by 25%. Proximal migration of the radius was small and was increased by 4.6 mm with radial head excision and by 1 mm after radial head replacement compared with the IOL-reconstructed, radial head-intact state. CONCLUSIONS: Interosseous ligament reconstruction may help improve treatment of longitudinal radioulnar dissociation but remains an experimental procedure.

Aged↗
PubMed2001

Precise ulna-shortening osteotomy with a new device.

Ulna-shortening osteotomy has become a standard procedure for various ulnar-sided wrist disorders. A precise osteotomy, good coaptation of the osteotomy surfaces, and rigid internal fixation are mandatory to achieve good results from ulna-shortening osteotomy. Various techniques and devices have been introduced to assist in this difficult procedure. We developed a device that enables a precise ulna-shortening osteotomy and fixation with a 3.5-mm AO dynamic compression plate. Twenty-four ulnas were shortened with the aid of this device. The average follow-up period was 36 months. Radiologic union occurred at an average of 8.1 weeks after surgery. There were no nonunions or delayed unions. This study shows that an ulna-shortening procedure with this device enables precise shortening and predictable union of the ulna.

Adolescent↗
PubMed2003

[Standardised operation technique for ulna-shortening with a new sliding-hole plate].

Ulna-shortening is a widely accepted procedure for the treatment of ulna-impaction syndrome. High rates of non-unions however necessitate improving the operation technique. The new device introduced in this study is a 7-hole plate in which two proximal holes are sliding-holes. By correct placement of two distal screws and two screws in the sliding-holes, rotational stability is guaranteed. The osteotomy is performed while the plate is loosely fixed to the ulna. After fixation of the two distal screws, the sliding-holes facilitate reposition with a good closure of the osteotomy gap. Excentric placement of two more screws and placement of a lag screw across the oblique osteotomy leads to further compression at the osteotomy site. Ulna-variance can be adjusted exactly. So far the plate has been implanted in 15 patients. Ulna-variance was reduced from + 2 to - 2.2 mm. The clinical results are comparable to those of ulna-shortenings in the literature. The sliding-hole plate allows an exact connection with good closure of the osteotomy without malrotation. With this simplified technique, the risk of non-union can be reduced.

Adult↗
PubMed1996

Differentiation of the bone-tissue remodeling response to axial and torsional loading in the turkey ulna.

The ability of bone tissue to differentiate between axial and torsional loading was determined with use of a functionally isolated turkey-ulna model of bone adaptation. Surface modeling and intracortical remodeling were quantified after four weeks of 5000 cycles per day of axial loading sufficient to cause 1000 microstrain normal to the long axis of the bone (five ulnae), 5000 cycles per day of torsional loading sufficient to cause 1000 microstrain of shear strain (five ulnae), or disuse (six ulnae). Of these three distinct regimens, only disuse caused a significant change in gross areal properties (12 per cent loss of bone; p < 0.05) as compared with those in the contralateral, intact control ulnae (sixteen ulnae). This finding suggested that both axial and torsional loading conditions were suitable substitutes for functional signals normally responsible for bone homeostasis. However, the intracortical response was strongly dependent on the manner in which the bone was loaded. Axial loading increased the number of intracortical pores by a factor of seven as compared with that in the controls (246 +/- 40.5 compared with 36 +/- 8.5 pores); it also increased the area lost because of porosis as compared with that in the controls (1.39 +/- 0.252 compared with 0.202 +/- 0.062 square millimeter); however, the mean size of the individual pores was similar to that in the controls (0.00565 +/- 0.0019 compared with 0.00561 +/- 0.0029 square millimeter). Conversely, torsional loading failed to increase substantially the number of pores (67 +/- 22.6 pores), the area of bone lost because of porosis (0.352 +/- 0.114 square millimeter), or the size of the pores (0.00525 +/- 0.0035 square millimeter) as compared with those in the controls. Although disuse failed to increase substantially the number of intracortical pores (59 +/- 22.4 pores), significant area (1.05 +/- 0.35 square millimeters; p < 0.05) was lost within the cortex because of a threefold increase in the mean size of each pore (0.0178 +/- 0.0126 square millimeter). It appears that bone tissue can readily differentiate between distinct components of the strain environment, with strain per se necessary to retain coupled formation and resorption, shear strain achieving this goal by maintaining the status quo, and axial strain increasing intracortical turnover but retaining coupling. While it is clear that load influences bone mass and morphology, it is also clear that specific parameters within the strain environment have distinct strategic roles in defining this architecture.

Adaptation, Physiological↗
PubMed1994

[Angioarchitecture of the ulna and radius and their practical relevance].

The periosteal and endosteal blood supply of the human ulna and radius was investigated by anatomical dissection. The main artery concerned is the anterior interosseous artery. It supplies the diaphysis of ulna and radius; its branches feed the distal one-fourths of both the ulna and the radius. The proximal one-fourth of the ulna is supplied by the ulnar artery, the ulnar recurrent artery and the recurrent interosseous artery. Periosteal branches of the common interosseous artery, the ulnar artery and the recurrent interosseous artery supply the proximal one-fourth of the radius. In both bones the main branch of the nutrient artery has an ascending course. The anterior interosseous artery, as the main artery of the periosteal and endosteal supply of the human ulna and radius, is important in transplantation and reconstruction, especially with a view to reducing the rate of pseudarthrosis. When osteosynthesis is planned so-called LC-DC plates should be chosen to preserve the periosteal branches. When a vascularized bone graft is taken from the forearm the vascularization of the remaining bones has to be considered. The vascularity of this area allows various options in grafting.

Arteries↗
PubMed1998

Patterns of strain in the macaque ulna during functional activity.

In vivo bone strain experiments were performed on the ulnae of three female rhesus macaques to test how the bone deforms during locomotion. The null hypothesis was that, in an animal moving its limbs predominantly in sagittal planes, the ulna experiences anteroposterior bending. Three rosette strain gauges were attached around the circumference of the bone slightly distal to midshaft. They permit a complete characterization of the ulna's loading environment. Strains were recorded during walking and galloping activities. Principal strains and strain directions relative to the long axis of the bone were calculated for each gauge site. In all three animals, the lateral cortex experienced higher tensile than compressive principal strains during the stance phase of walking. Compressive strains predominated at the medial cortex of two animals (the gauge on this cortex of the third animal did not function). The posterior cortex was subject to lower strains; the nature of the strain was highly dependent on precise gauge position. The greater principal strains were aligned closely with the long axis of the bone in two animals, whereas they deviated up to 45 degrees from the long axis in the third animal. A gait change from walk to gallop was recorded for one animal. It was not accompanied by an incremental change in strain magnitudes. Strains are at the low end of the range of strain magnitudes recorded for walking gaits of nonprimate mammals. The measured distribution of strains in the rhesus monkey ulna indicates that mediolateral bending, rather than anteroposterior bending, is the predominant loading regime, with the neutral axis of bending running from anterior and slightly medial to posterior and slightly lateral. A variable degree of torsion was superimposed over this bending regime. Ulnar mediolateral bending is apparently caused by a ground reaction force vector that passes medial to the forearm. The macaque ulna is not reinforced in the plane of bending. The lack of buttressing in the loaded plane and the somewhat counterintuitive bending direction recommend caution with regard to conventional interpretations of long bone cross-sectional geometry.

Animals↗
PubMed2005

Development of the subchondral bone layer of the medial coronoid process of the canine ulna.

The medial coronoid process (MCP) of the ulna takes part in the weight-bearing function of the elbow in quadrupedal animals. In this study, the timing of development of a solid subchondral bone layer (SBL) of the MCP in the dog is investigated, as this might be important in the pathogenesis of the fractured medial coronoid process, a common disease in young dogs of larger breeds. The SBL is considered to make an important contribution to the strength of the MCP. In this study, the SBL is visualized at the humeral articular side (H-side) and in the radial notch (RN) via three-dimensional reconstructions of micro-CT scans (34 mum voxel size) in nine young golden retrievers. After micro-CT scanning, the area was investigated histologically. Gradually, the appearance of the SBL on the H-side changes from a trabecular aspect to an even surface with gaps and finally to a completely even surface. The surface in the RN is still rough at 24 weeks after birth, although some consolidation has occurred. Initially, the enchondral ossification activity, as observed in the histological sections, is high, but later, when the intertrabecular spaces are filled in with calcified cartilage and bone, activity is less evident. Some vessels penetrated the SBL, but it is unclear if they account for all the gaps in the surface seen in micro-CT. In addition, the formation of a cortical structure of the proximal ulnar shaft could be visualized. The bony cortex is already even at the mediocaudal side of the proximal ulna 4 weeks after birth, but remains trabecular at the dorsal side until 6 weeks later. We hypothesize that the observed differences in the formation of an even SBL or cortex can be explained by mechanical factors. A smooth cortical layer has an even thickness and will be stronger than a cortex with varying thickness. In the MCP, compressive forces exerted by the humerus may be responsible for the early smoothening on the H-side. In the proximal ulna, the resistance to bending in the sagittal plane will depend mainly on the caudal surface of the ulna (and dorsal surface of the radius), surfaces furthest away from the neutral axis. At least the caudal ulna smoothened first, thus providing stiffness against bending at an early age.

Animals↗
PubMed1998

Wide excision of the distal ulna: a multicenter case study.

Excision of the distal ulna to treat degenerative disease or instability has fallen into disfavor following reports of radioulnar impingement, carpal instability, and distal ulnar instability. Alternative procedures for reconstruction of the painful distal ulna have been developed to address these problems; the results have been generally favorable. When faced with distal ulnar reconstruction that has failed after multiple surgical procedures, or a distal ulnar neoplasm, the surgeon is left with few treatment options. Creation of a one-bone forearm, free fibular transfer, and allograft replacement have been attempted, with mixed outcomes. We report the results of 5 men and 7 women who underwent wide excision of the distal ulna, defined as surgical excision of 25% to 50% of the ulnar length. The diagnosis was failed distal radioulnar reconstruction or excision in 8 patients, osteomyelitis in 1, congenital pseudoarthrosis of the radius in 1, and neoplasm in 2. No soft tissue reconstruction was performed. Patients were examined at an average of 22 months after surgery for radiocarpal and radioulnar instability, functional outcome, pain relief, grip strength, and range of motion. Nine of the 12 procedures resulted in good or excellent results; 1 patient had a fair result after resection for osteosarcoma, and the procedure in 2 patients failed, requiring conversion to a one-bone forearm. Grip strength was restored to 75% of the normal side and range of motion was restored to 86% of the normal side. Wide excision of the distal ulna without soft tissue reconstruction is a simple and durable treatment of neoplasms of the distal ulna or salvage of the failed reconstruction of the distal radioulnar joint. We do not recommend its use in patients with incompetency or disruption of the interosseous membrane.

Adult↗
PubMed2004

Height prediction from ulna length.

Height is fundamental to assessing growth and nutrition, calculating body surface area, and predicting pulmonary function in childhood. Its measurement is hindered by muscle weakness, joint, or spinal deformity. Arm span has been used as a substitute, but is inaccurate. The objective of the study was to identify a limb measurement that precisely and reproducibly predicts height in childhood. Males (n=1144) and females (n=1199), aged 5 years 4 months to 19 years 7 months, without disability were recruited from Melbourne schools. Height, arm span, ulna, forearm, tibia, and lower leg lengths were measured with a Harpenden stadiometer and anthropometer. Prediction equations for height based on ulna length (U) and age in years (A) were developed using linear regression. Ulna centile charts were developed by the LMS method. For males, height (cm)=4.605U+1.308A+28.003 (R2=0.96); for females, height (cm)=4.459U+1.315A+31.485 (R2=0.94). Intra- and inter-observer variability was 0.41% and 0.61% relative to the mean, respectively. Height prediction equations from tibia, forearm, and lower leg length were calculated. We show that ulna measurement is reproducible and precisely predicts height in school-age children. It appears to be superior to arm span measurement when neuromuscular weakness, joint, or spinal deformity exists. Ulna growth charts should facilitate growth assessment.

Adolescent↗
PubMedDate not supplied

Fatigue fracture of the ulna occurring in pitchers of fast-pitch softball.

We have reported three cases of fatigue fracture of the ulna in male pitchers of fast-pitch softball. To elucidate the etiology of injury, we first selected three healthy male and three healthy female pitchers from a well-trained college team and analyzed their forearm movement by high-speed cinematography. This showed slight flexion of the elbow joints during wind-up motion, dorsal flexion of the hand joints upon releasing the ball, and extreme pronation of the forearms during the follow-through. We then took 8 mm CT scanning sections of the forearms. Using these images, we investigated shapes and areas of cross-sections of the ulna and its cortical and cancellous bones from the elbow to the hand joints. Our results reveal that the shapes of the sections are significantly different from circles at around the center of the ulna, and the cross-sectional areas are smaller in the middle one-third of the ulna than in other parts. These observations imply that fatigue fractures of the ulna in pitchers of fast-pitch softball must be torsionally induced, tending to occur at the middle one-third of the bone.

Adolescent↗
PubMed2006

Resection of the distal ulna for tumours and stabilisation of the stump. A case report and literature review.

The distal end of the ulna is an uncommon site for primary bone tumours. We report the case of a 23-year-old male, with a giant-cell tumour of the distal end of the ulna treated with en-bloc resection and stabilisation of the ulnar stump using one half of the extensor carpi ulnaris tendon. The amount of bone removed from the distal end of the ulna was 9.0 centimeters long. The functional and oncological results were excellent. Stabilisation of the ulnar stump, using one half of the extensor carpi ulnaris tendon, has been described by Goldner and Hayes in 1979, after resection of a relatively small segment of the distal ulna. This is the first report on this technique for stabilisation of the ulnar stump after resection of a large distal ulnar segment. A literature review of reported cases with a resection of the distal ulna for primary bone tumours is presented. The available data are inconclusive as to whether a simple excision is adequate or a reconstruction/stabilisation is required.

Adult↗
PubMed1990

[Bone response to unphysiological mechanical stress. A histomorphological study on modelling and remodelling of Martin's transformation zone in the ulna].

In this study the morphological changes in the shape and structure of the ulna were investigated following resection of a mid-shaft segment in the radius. These morphological alterations are called in German "Martin'sche Umbauzone" (MUZ; Martin's transformation zone). Various explanations for the MUZ can be found in the literature; Wolff's law, in particular, offers hints about the development of this phenomenon. The morphological changes in the ulna were investigated by microangiography, polarized light and fluorescence microscopy as well as by micro-radiography. The radius was operated on in 36 mongrel dogs. The development and localization of new bone formation at the endosteal and periosteal envelope of the ulna were studied. The woven bone formation of the envelopes (modelling) and the intracortical remodelling in the distal part of the ulnae were compared with the intact ulnae of the opposite extremities. It is concluded from these morphological alterations that the experimental design chosen provides a valuable, tissue-related model for the investigation of morphogenesis in bones. Further investigations will deal with the correlation between strain and new bone formation.

Animals↗
PubMed2000

Radial head dislocation with plastic deformation of the ulna in children. A rare and frequently missed condition.

Although often reported in the literature, 'isolated' traumatic radial head dislocation in children is a rare condition which has not been studied extensively. There is very often a delay in diagnosis and treatment. Lincoln and Mubarak described the 'ulnar bow sign' in 1994. They accurately described the plastic deformity of the ulna and explained how to make a correct diagnosis from the radiographs. Probably most 'isolated' radial head dislocations in children are associated with plastic deformation of the ulna as stated in 1984 by Dubuc et al. (2). The recognition of these "plastic" Monteggia fractures is mandatory, as action on the ulna plays a central role in the treatment. On the other hand, the 'ulnar bow sign' may be used to detect subtle changes in the position of the radial head. We present 4 cases of chronic radial head dislocation associated with plastic deformation of the ulna. Open reduction of the radial head and reconstruction of the annular ligament was performed. An osteotomy of the ulna was deemed necessary in 3 cases.

Bone Nails↗
PubMed2002

An anthropometric study of the distal ulna: implications for implant design.

Arthroplasty of the distal ulna is frequently used for distal radioulnar joint disorders; however, prosthetic failures are common. An implant replicating the ulna may be advantageous from the viewpoint of joint kinematics, wear, and fixation. The geometry of 40 distal ulnas was quantified by computed tomography scanning and radiography. Ulnar head diameter (16.8 +/- 1.6 mm), canal diameter (8.3 +/- 1.6 mm), eccentricity of the head relative to the shaft (2.5 +/- 1.4 mm), and angle of articulation (176 degrees +/- 29 degrees ) were measured. No correlation was found between the diameters of the ulnar head and intramedullary canal (R(2) = 0.2). A modular head-stem system with an eccentric offset may best reproduce the geometry of the distal ulna.

Adult↗