1. Case Description

An 8-year-old, 300 kg, racing Kurd stallion was presented to the Urmia University– Veterinary Teaching Hospital (Urmia – Iran) for evaluation of a 75-day duration of right forelimb lameness while galloping.

2. Clinical Findings

According to the owner the horse had stumbled on his right forelimb and found 2 days in a non-weight bearing stance with a painful swelling felt on the right elbow on palpation. A single dose of flunixin meglumine (Razak Co., Tehran, Iran) had been administered by a local veterinarian and the horse was subjected to stall rest for a month. Then the horse had been returned to service and lameness was seen while galloping. After one month more stall resting the horse was presented to the hospital. On physical examination no swelling was observed, however, pain was felt on palpation of the right elbow. The horse was bright, alert and responsive with no signs of lameness while walking (Fig 1). All vital parameters were within normal limits. 

Figure 1. The horse with olecranon fracture was bright, alert and responsive with no signs of lameness in walking.

3. Treatment and Outcome

Radiographic examination revealed a complete transverse diaphyseal non-articular/non-displaced fracture of olecranon and a longitudinal fracture of ulna. The anconeal process and the semilunar portion were not involved.

Radiographic examination (Kvp68, mAs6) revealed a comminuted fracture of olecranon involving non-articular portion of trochlear notch of the ulna. A large and a small fragment of fractured bone were separated from ulna and callus formation irregularities were also observed in periphery of fracture lines (Fig. 2). Regarding involvement of non-articular portion of trochlear notch of the ulna the horse was recommended to have complete stall rest for 60 days without external coaptation.

Figure 2. Lateromedial slightly oblique radiograph and schematic representation of an eight-year old mare elbow with chronic comminuted fracture of the olecranon. The accident occurred 2/5 month ago and she was showing lameness only in trot pace. Although one of the fracture lines entered the trochlear notch of the ulna, it involved the non-articular area. 1, Olecranon; 2, Anconeal process; 3, Medial condyle of humerus; 4,  Lateral condyle of humerus; 5, Medial epicondyle; 6, Lateral epicondyle; 7, Rdius; 8, Radial tuberosity; 9, Interosseous space; 10, Transverse fracture line of olecranon; 11, Fracture distal line; 12 and 13, Two fragments of bone in fracture area. 

4. Clinical Relevance

Fractures of the ulna and olecranon are relatively common in horses and are primarily caused by external trauma.^1,2 Clinical signs usually associated with olecranon fractures are manifested as an inability to bear weight on the injured limb and the classic “dropped elbow” stance. However, a small percentage of horses may still be able to bear weight on the limb with different grades of lameness.³

Different surgical techniques to repair olecranon fractures in horses such as tension band plate, tension band wiring including wires alone or in combination with pins or screws and hook plate fixation have been reported.^3-10

These fractures have also been treated non-surgically by stall rest with or without external coaptation and surgically by means of internal fixation and there have been numerous reports on internal fixation of olecranon and ulnar fractures.^7,11-15 However, most have involved small numbers of horses, making it difficult to draw definite conclusions about overall success rate. Overall, satisfactory results have been reported in 50 of 65 horses.^12-15 The treatment depends on fracture configuration and patient age, but most are treated by internal fixation using a bone plate applied to the caudal aspect of the bone, and the prognosis for return to full function is favorable in most cases.^16,17

Several reports describe the benefits and the excellent results obtained with open reduction and internal fixation of olecranon fractures.^3,5,12,18-21 A retrospective study of 29 olecranon fractures surgically repaired with a tension band plate revealed a success rate of 68%, with 84% of these horses returning to athletic function.¹⁸ In another study of 21 cases of olecranon fractures also treated with tension band plating, 76% of the horses regained full limb function.¹⁹ In both studies, type-2 fractures were the most common configuration. In addition, a recent report describing the racing prognosis for horses undergoing internal fixation of olecranon fractures by different methods of stabilization (i.e. DCP, hook plate and tension band wires) has shown an overall favorable prognosis for racing, being the DCP the most commonly employed method of repair.²¹ A more recent series of type-5 olecranon fractures in 20 horses treated surgically by plate fixation has shown that 13 of the 15 horses (87%) of which long-term follow up was available returned to athletic use or were in training.³In previous reports of nonsurgical treatment of ulnar fractures, results were satisfactory, unsatisfactory, and mixed.^7,9,10,15

The cause of the fracture is associated with direct trauma usually produced by a kick or a fall (Richardson, 2000; Watkins, 2006).^1,2 Other reported causes of trauma include horse fights, hit by vehicle, caught in fencing and difficult anesthetic recovery.³ In the case reported here the origin of the trauma was stumbling on the affected limb. The characteristic position of semi-flexed carpus and fetlock and “drooped elbow” adopted by many horses with olecranon fractures is explained by the disruption of the triceps brachii muscle. The triceps muscle inserts on the olecranon process. Upward traction of the olecranon produced by the triceps contraction extends the elbow joint. When the elbow is extended, the other joints of the forelimb are passively fixed in the weight bearing position by the stay apparatus. Therefore, the ability of the horse to fully extend the forelimb and fix it in the weight bearing position relies on the integrity of the olecranon. Although the “dropped elbow” is a well-known clinical sign of horses with olecranon fractures, care should be exercised to differentiate it from other conditions such as radial nerve paralysis and humeral fractures based solely on the clinical presentation.^16,17

Controversy exists among authors in regard to the most common type of olecranon fracture. Whereas type-2 olecranon fractures (Fig. 3) have been reported as the most common fracture.^8,18,19

Figure 3.  Classification of olecranon fractures.²³

Treatment selection for cases of olecranon fractures is dictated by the configuration of the fracture, its level at the olecranon in relation to the radio-humeral articulation and the age and weight of the horse.^1,2,17,22 An overall poor prognosis for recovery has been shown after nonsurgical treatment of ulnar fractures.¹⁵ Therefore, nonsurgical treatment (i.e. stall rest and full-limb splinting) has only been recommended for non-articular/non-displaced fractures.^18,19 Although nonsurgical treatment has been an affordable and successful option for treatment of non-articular/non-displaced fractures decreased convalescence period and improved level of comfort can be attained by treating these cases surgically.¹⁶

Nonsurgical management of ulnar fractures, although widely practiced, appears to be less rewarding than surgical management by internal fixation. Nonsurgical treatment should be elected only in cases where economics is of primary concern, when the fracture involves only the distal portion of the semilunar notch, or when severe comminution of fracture fragments precludes any attempt at surgical reconstruction.¹⁵

Following 2 months in a telephone conversation with owner, it was found out that she did not show any sign of lameness even in gallop. Unfortunately, we could not convince the owner to get her to the hospital for follow-up radiography.   

Apart from treatment selection for cases of olecranon fractures, it should be taken into consideration that uncomplicated olecranon fractures with late referral to the clinic may go unnoticed because of no lameness in physical examinations.

Acknowledgment

 The authors are grateful to the Staff of VMTH, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran for the support.

Conflict of interests

 None