dog radius and ulna radiograph
the radius and ulna. Depending on the location and amount of energy of each particular trauma, fractures can occur in various portions of the bone. Although the bones rest closely together, they are joined not by an osseous union, but rather by numerous soft tissue attachments. Distally, the ulna similarly articulates with the radius along its medial cortex, where it rests within the ulnar notch. Retardation of growth of the distal ulnar physis can result not only in a shortened ulna but, because of intimate attachments between radius and ulna, in conformational changes in the radius. Canine Radius and Ulna Example 1. The alternative is to delay surgery until the animal is mature, at which time a definitive correction can be completed with no risk of subsequent reangulation. 3. and ulna regardless of the pathophysiology whether these lesions may be a manifestation of chronic interosseous desmopathy or any cause for ischaemia. If attempted in puppies, the risk exists that the narrowed ostectomy gap may heal before cessation of longitudinal growth (even if slowed) of the radius, resulting in loss of elbow joint congruence yet again. The IHC Group. The antebrachium comprises two bones, the radius and ulna, which cross one another in the frontal plane as they extend from the elbow joint proximally to the carpus distally (Figure 55-1). Acute elongation techniques involve an osteotomy of the radius, the use of bone spreaders for radial distraction, and subsequent stabilization with a bone plate or an external skeletal fixator. This causes forward bowing of the forearm with lateral (outward) deviation of the carpus. Specific palpation of the forearm and finding swelling, bruising, and crepitation (abnormal “crunchy” feeling with motion) can be highly suggestive of a fracture of the radius and ulna. Acute distractions can be hampered by the strength of the large amount of soft tissue connection (described in anatomy section) between radius and ulna; thus dynamic distraction may be a more feasible option for stretching the soft tissues joining the two bones. This is considered the current standard of care. These fractures, also known as “pathologic fractures,”can occur if the animal is malnourished, has a systemic illness such as kidney disease, has an endocrine disorder such as hyperparathyroidism, has a bone infection (osteomyelitis) or has cancer of the bone. This was studied in the dog by radiographic assessment of 20 limbs of a variety of nonchondrodystrophic breeds.17 In the frontal plane, joint orientation lines of the elbow can be determined by drawing a straight line from the proximal-lateral-most aspect of the radial head to the proximal-most aspect of the medial coronoid process (Figure 55-3, A). Additional tests may include: Emergency care for concurrent problems is paramount. This process can also be completed in the sagittal plane, where the joint orientation lines are generated from the most proximal aspects of the radial head, both cranially and caudally, for the elbow joint, and upon the most cranial and caudal distal aspects of the radius for the radiocarpal joint (Figure 55-4, A, B). However, osteotomies, rather than ostectomies, are commonly performed when the patient is mature, as early osseous union is encouraged in this situation. Affected dogs exhibit acute onset of swelling over the distal limbs, severe pain, anorexia and fever. Signs of radial or ulnar fractures in dogs may include: A thorough physical examination is important to determine if fractures are present and to determine if there are other injuries. The biceps brachii and brachialis muscles each have tendons of insertion that bifurcate and insert on the medial surface of the radius and the ulna. Using the values of joint orientation angles as measured from the contralateral normal side, the radial anatomic axes are determined. Recommendations of one small retrospective study suggest that despite diagnosing and treating affected animals at a young age (5 months), the technique was still frequently unsuccessful. Premature closure of the distal ulnar physis has been reported to be the most frequent growth plate injury in dogs, accounting for 63% of all physeal insults.48 It is well accepted that the geometric configuration of the distal ulnar growth plate is the primary reason why the distal ulna is affected by premature physeal closure. Open growth plates are visible at the proximal and distal radius and ulna. The ligament proper terminates distally about midshaft of the antebrachium, where the two bones diverge medially and laterally as they cross one another. A, Elbow joint orientation line (green) drawn from the proximocranial aspect of the radial head to the proximocaudal aspect. Thus 3D modeling can serve as a diagnostic alternative to arthroscopy. Diagnosing and quantifying the condition can be challenging if the degree of shortening is very slight. Further, sawing may be ceased before cutting entirely through the cranial ulnar cortex, thus allowing the ostectomy to be completed with an osteotome, again protecting the disruption of the periosteum or cortex on the caudal aspect of the adjacent radius. Playing and rough-housing should be avoided, even if he appears to be feeling well. Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on Google+ (Opens in new window) The oblique nature of the osteotomy will help prevent caudal rotational displacement of the distal aspect of the proximal segment with pull of the triceps brachii muscle on the olecranon. When applied in vitro to compensate for the opposite condition of radial shortening, ostectomy of the ulna distal to the interosseous ligament did not allow adequate movement of the ulna in one study. It is a malignant cancer called osteosarcoma. DIAGNOSIS. The influence of the procedure with respect to reestablishing normal antebrachial bone and joint alignment, or on the resolution of associated lameness, has never been prospectively studied in a large number of juvenile dogs. Methods used to try to prevent the ostectomy site from healing too quickly include creation of an ostectomy gap greater than 1.5 times the diameter of the bone,*,54 removal of all periosteum in the vicinity of the ostectomy,10 and insertion of a fat graft.9, Semi-controlled and controlled systems of guiding the movement of the proximal ulna are similar to what was previously discussed for the radius, including older methods of distracting fixators and using pins in both the humerus and the proximal ulna connected by an elastic band.35 These methods have largely been replaced by the use of circular external skeletal fixators. A, Medial aspect. Animals of both sexes and of any age are susceptible to this type of trauma if not kept restrained. However, another study has reported clinical success with low ulnar osteotomies for treatment of premature closure of the distal ulnar physis.21 For example, if a young patient is presented with premature closure of the distal ulnar physis with subsequent radial angulation, an ulnar osteotomy can be attempted to try to improve elbow joint incongruity and to release the bowstring effect of the affected ulna on radial development. The location of this intersection demarcates the CORA in the sagittal plane. A normal radius and ulna on a radiograph. Because of the conformation of the forearm, both bones, the radius and ulna, usually fracture at the same time. This technique obviates the need to move the radial head to a specific position, as occurs with any of the radial lengthening procedures. The medial and lateral collateral ligaments of the elbow joint also tether the radius and ulna together. Abnormalities can also occur in the elbow secondary to this type of growth plate injury. Here is Kaiser after his splint was applied. Figure 55-2 Ligaments of the left elbow joint. A strong interosseous ligament is located at the junction of the proximal and middle third of the lateral aspect of the radius and ulna. Radius and ulna, sagittal plane: Joint orientation lines, radial anatomic axis, and joint orientation angles. For cases of more severe radial valgus, or when the angulation is not as previously described, but rather appears as varus, recurvatum, or internal rotation of the distal radius, then radial corrective measures are necessary. Symmetric premature closure of the distal radial physis has been created in juvenile dogs experimentally through irradiation, thus serving as a model for the clinical scenario.40 Through this study, it was determined that when the distal radial physis is symmetrically insulted, the proximal physis assumes the majority of longitudinal growth in the radius, as the amount of elongation of the distal radius slows dramatically. Over a period of 14 days, the radial head was able to slide proximally, eventually matching the coronoid process and reestablishing contact with the humeral capitulum. College of Veterinary Medicine • … Rare Earth screens with a speed of 200 or less are recommended. In general, gradual, dynamic elongation following the principles of distraction osteogenesis (discussed in greater detail in Chapter 41) has advantages in the young animal, as these techniques allow some adjustability to adapt to the dog’s continued growth. Longitudinal growth may continue uninterrupted from these relatively flat physes, as long as the germinal cells are uninjured and remain attached to the epiphysis. The ulna is … Radius. This procedure frees the proximal aspect of the ulna, so it is no longer constrained by retarded growth of the distal physis, thereby allowing the ulna to move proximally and optimize congruency with the humerus. Abnormal radial growth with relative overgrowth of ulna leads to elbow subluxation. Any condition that results in radioulnar synostosis before closure of the proximal radial physis may produce a shortened ulna.39 In the absence of antebrachial angulation, the main surgical treatment for a shortened ulna is a lengthening procedure. Thus, excessive force applied from any direction can cause compression of one side of the conical physis, resulting in injury to the germinal cells and subsequent retardation or cessation of ulnar growth.18 Although trauma is a frequent cause of premature closure of this growth plate, the heritability of premature ulnar physeal closure as related to conformational development of specific breeds has also been reported.28. The rapid decline in growth that occurs at the level of the distal radius also slows growth at the distal ulnar physis. D, Joint orientation angles (yellow) determined from the intersection of the joint orientation lines and the anatomic axes. Radial lengthening can be completed acutely or gradually, and gradual elongation can be controlled or semi-controlled. Important to note with this technique, however, is that with more aggressive ostectomies (in younger patients), or with cases of more severe ulnar shortening (where the resulting gap will be larger), the resulting gap may be so great as to prohibit the ends of an oblique osteotomy from contacting one another, thus rendering the technique to combat bending nonuseful. Utilizing a cadaver model, Mason et al.34 determined the sensitivity and specificity of lateral radiographic projections to be 78% and 86%, respectively. This is of importance when attempting to surgically move a portion of one bone separate from the other, as is often necessary to treat some pathologic conditions. An alternative to radial lengthening is shortening of the ulna by completion of an ulnar ostectomy.19,46 The advantage of this technique is that, if the ulnar ostectomy is completed in a dynamic fashion (without rigid fixation), the dog’s humerus will compress the ostectomized ulna to a level where the coronoid processes match the radial head during weight bearing.