Olecranon

Tophi (urate deposits) are uncommon in gouty subjects and are a late complication of hyperuricemia. The most common sites of tophaceous deposits in patients with recurrent acute gouty arthritis are the base of the great toe, helix of the ear, olecranon bursae, Achilles tendon, knees, wrists, and hands. 

A number of different sites have been used to apply the pinch. The most commonly used site is over the triceps muscle of the arm. Hence, e site is called the "triceps skinfold" site. The measurement is taken halfway between two bones, the scapula and ulna. More specifically, the measurement is taken halfway between the acromion process of the scapula and the olecranon process of the ulna (Figure 7.9). A picture of a dietician taking a triceps skinfold measurement is shown in Figure 7.9. 

Sleeve avulsion fractures are a particular form of avulsion injury seen in the unossified skeleton which differs from avulsions in adults because the sleeve of periosteum which is pulled off can continue to form bone if not treated. The typical location is at the lower pole of the patella, but the upper pole of the patella, the olecranon and the medial epicondyle can also be affected. Ultrasound demonstrates a sleeve of cartilage that has been avulsed usually with a small fragment of bone (Hunt and Somashekar 2005). In some cases a double cortical sign may be present, indicating elevation of a superficial layer of cortex from the underlying bone. There maybe associated haemarthrosis and patella alta (Fig. 4.14). 

Fig. 7.16. Separate ossification centres for the olecranon in an adolescent boy (arrowheads)...

An estimation of the distribution of fracture patterns about the elbow is supracondylar (70%), lateral condyle (15%), medial epicondyle (10%), olecranon (5%), radial neck (1%), medial condyle (1%), capitel-lum (1%), T condylar (<1 %). 

The blood supply to the capitellum is via end arterioles from the inferior ulnar collateral artery crossing the olecranon fossa posteriorly into the lateral condyle to the ossific nucleus of the capitellum. This predisposes to avascular necrosis following displaced capitellar fractures. 

Fig. 18.1a-g. Serial radiographs of the elbow showing the typical sequence of the appearance of the ossification centres, a No ossified centres b capitellum c radial head d internal (medial) humeral apophysis e trochlea f olecranon and g external (lateral) humeral apophysis... 

The teardrop or hourglass sign is formed by the anterior margin of the olecranon fossa and the posterior margin of the coronoid fossa with the capitellum forming the inferior portion. The capi-tellum and trochlea (if ossified) should be super-... 

The articular surfaces of the elbow are contained within the joint capsule, which also encloses non-articular surfaces, including the coronoid, radial fossa and olecranon fossae. It attaches just distal to the coronoid and olecranon processes. The whole of the radial head is within the capsule. 

Three fat pads lie over the capsule, the anterior over the coronoid fossa, the posterior over the olecranon fossa and a third over the supinator as it wraps over the radius. Fracture, haematoma and effusion into an intact capsule may cause capsular distension, which can distort these fat pads, improving their visibility and identifying occult fractures (Fig. 18.4). In the setting of acute trauma, a visible... 

Some fractures may be reduced by closed manipulation and stabilisedby percutaneous K-wires. Evaluation of fracture reduction may be aided by intraoperative arthrogram. The most stable and therefore ideal configuration of K-wires is for a common entry point on the lateral edge of the condyle, with one wire running transversely to the medial condyle, and the second at about 60 aiming at the medial cortex above the olecranon fossa. 

A number of equivalent lesions have also been described. Commonest of these is the Type 1 variant Where the radial head is dislocated anteriorly but the ulna has plastic deformation rather than a fracture. Other variants include dislocations with associated radial neck fractures, olecranon fractures and dislocations of the ulnar-humeral joint. In some respects, the pulled elbow , commonly seen in infants, can also be considered a Bado I equivalent. The injury occurs when the elbow has traction applied, usually resulting in hyperextension and pronation. The radial head subluxes through the annular ligament but does not truly dislocate and radiographs are either normal or will show an effusion with elevation of the fat pads. 

Fractures of the radial neck maybe isolated injuries but can occur in association with medial epicondyle avulsions, fractures of the olecranon and dislocations of the elbow joint. 

Olecranon fractures are occasionally seen in children and account for about 5% of fractures about the elbow. Fortunately, the majority of injuries are minimally displaced, and are managed non-operatively. A significant number of fractures have associated injury either to the elbow or to the wrist. 

Metaphyseal fractures can be classified according to mechanism of injury. The majority of injuries occur with the elbow in extension, the olecranon locked in the olecranon fossa and the maximum stress developed in the proximal metaphyseal region leading to fracture. When a valgus stress is applied, there may be asso ciated compression fractures of the radial neck and avulsion of the medial epicondyle. Varus stress is associated with radial head subluxation. 

Injuries with the elbow flexed during a fall occur as the olecranon is stressed over the fulcrum of the trochlea as the triceps attempt to resist the force acting on the distal ulna (Fig. 18.20). The line of fracture is oblique and intra-articular. This mechanism may also produce an extensor avulsion of the apophysis. 

In a flexed elbow, a direct blow to the posterior aspect of the ulna, just anterior to the distal humerus, can cause a shear stress on the olecranon metaphysis, breaching the anterior cortex and with the radius and distal ulnar fragment displaced anteriorly by the pull of the brachialis and biceps. This may occur with the elbow either flexed or extended, leading to either a transverse or oblique fracture pattern (Table 18.2). 

Fig. 18.20. Flexion type (Wilkins A) fracture of the olecranon through the metaphysis...

Treated isolated fractures of the olecranon have been shown to have an excellent long-term outcome (Gicquel et al. 2001). Delayed union and malunion are possible complications of early displacement of... 

Childress HM (1975) Recurrent ulna nerve dislocation at the elbow. Clin Orthop 108 168-173 Evans MC, Graham HK (1999a) Olecranon fractures in children. J Pediatr Orthop 19 559-569 Evans MC, Graham HK (1999b) Radial neck fractures in children a management algorithm J Pediatr Orthop Part B 8 93-99... 

Male 70 Finger, toes olecranon bursa Recurrent pulmonary emboli Frusemide 550 60... 

Maiininen, M.J. (1991). Absorbable poly 1-lactide screws in the fixation of olecranon osteotomy in sheep. Proceedings of the 9th European Conference on Biomateiials, Chester, UK, p. 213. 

Malkin J, Shiimpton A, Wiselka M, Barer MR, Duddridge M, Pereta N. Olecranon bursitis secondary to Mycobacterium kansasii infection in a patient receiving infliximab for Behget s disease. J Med Microbiol 2009 58(3) 371-3. 

C7—Trieeps reflex, tested on the triceps tendon over the posterior olecranon process... 

Extension of the elbow from the anatomic position is limited (5 to 10 degrees) by contact of the olecranon process with the fossa, tension in the anterior ligament, and resistance of anterior muscles. The triceps brachii is the only significant elbow muscle that functions in extension. There is some minor contribution by the anconeus. Because most elbow extension is accomplished by gravity, the triceps functions primarily against resistance. 

Supination is the rotary motion that turns the palm of the hand toward the ceiling pronation is the rotary motion that turns the palm toward the floor. In neutral rotation, the palm faces medially with the thumb up. The total range of rotation is approximately 180 degrees. Proximally, the olecranon process has minor coupled motions during pronation and supination. Supination is accompanied by a slight amount of adduction of the olecranon process while some slight amount of abduction occurs during pronation. 

Somatic dysfunctions can involve contraction of the related muscles, compression of the neural elements, strain of the ligamentous aspects, and restriction primarily of the secondary motions of the joint components. The radial head typically entails posterior or anterior dysfunctions and may involve the muscles, the annular ligament, and the lateral collateral ligament. The humero-olecranon dysfunctions can involve the muscles, the medial collateral ligament, and can be related to symptoms involving the ulnar nerve. Restriction of elbow... 

The elbow should be examined first by observation. The carrying angle of the elbow should be noted, as should any swelling, which may be diffuse or localized to the olecranon bursa posteriorly. Signs of old or new trauma should be noted, such as scars, abrasions, bruises, and the like. 

The soft tissues and bony structures are then palpated to evaluate the integrity of the bones and the presence of any tenderness, masses, asymmetries, or crepitus. Any temperature changes should be noted, especially over the bursa and around the joints. Bony landmarks should be identified and compared between elbows. Swelling, especially over the olecranon bursa, should be noted. The olecranon bursa should not be palpable unless it is filled with fluid or thickened. 

Triceps reflex elicited by tapping the triceps tendon on the posterior arm just above the olecranon tests C7. 

Tinel test This is performed by tapping over the ulnar nerve as it passes between the olecranon and medial epicondyl. Marked sensitivity may be indicative of a neuroma or inflammation of the ulnar nerve. 

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