Nonunion of the Olecranon and Proximal Ulna

General Considerations

Nonunion of proximal ulna fractures is relatively uncommon with current osteosynthesis techniques. One 2008 series reported 2 of the 62 cases (3%) with olecranon fractures who had nonunions after fixation by tension band wiring techniques. Although this problem is perhaps less common today than in the past, it continues to challenge the orthopedic surgeon. Olecranon and proximal ulna fracture nonunion can result in profound functional disability with pain, instability, or limitation of elbow joint motion.

Pediatric proximal fractures and nonunions pose unique problems and are discussed elsewhere ( Chapter 31 ).

Incidence

Nonunion of the proximal ulna and olecranon has been reported to occur in 5% of olecranon fractures and represent approximately 5% of all nonunions. At the Mayo Clinic in a 10-year period (1980–1990) there were only two nonunions among 196 olecranon fractures (1%). These figures are roughly comparable to the rate of nonunion after olecranon osteotomy for joint exposure. However, the incidence of olecranon osteotomy nonunion is quite variable and has been reported in up to 30% of fractures.

Diagnosis

Six months is the generally accepted time interval to make the diagnosis of a nonunion. A delayed union usually maintains the radiographic appearance of the early stages of a healing fracture. Subsequently, reactive hyperemia, early resorption of bone ends, and some widening of the fracture site define an established nonunion. With a nonunion, all evidence of bone healing has ceased. The bone ends and medullary canals are capped, the endosteal blood supply does not cross the fracture site, and sclerosis of the bone ends is present. In questionable cases, a computed tomography scan makes the diagnosis.

Clinical Presentation

Clinically, tenderness is consistently reported, often with some degree of instability and limitation of motion. Yet chronic repetitive use has been implicated in the occurrence of stress reactions around the olecranon in throwers, weightlifters, and gymnasts. It may thus come as no surprise to learn that a small percentage of patients may be relatively asymptomatic.

Factors Causing Nonunion

Fracture separation of a nonunited ossification center in three adults has been reported. Primary bone grafting is recommended in these cases because of the high incidence of fibrous nonunion following simple open reduction and internal fixation.

Walker reported a case of painful unilateral physeal nonunion in an adult weightlifter. After failure of conservative treatment, surgical union was achieved using tension band wiring augmented with an autologous iliac crest bone graft. Unilateral olecranon physeal nonunion may have a mechanical etiology as opposed to a genetic etiology in individuals with bilateral physeal persistence. Generally, children have a higher rate of periosteal response and hence these types of fractures heal reliably with fixation. In 2006, Rettig reported on five baseball players with physeal stress fractures, all of whom healed in 15 weeks after screw fixation.

Fractures in the older age group tend to heal at a slower rate than those in the younger patient. Other causes of delayed union include diabetes, irradiation, and smoking.

The main reasons for nonunion of the proximal ulna are inadequate fixation, premature motion, smoking, or some combination of these. Other possibly more obvious factors that correlate to nonunion include (1) inadequate fixation or immobilization, (2) distraction, (3) compounded fracture, (4) infection, (5) comminution, (6) devitalization, (7) soft tissue interposition, and (8) abnormalities of the electrochemical or cellular physiologic mechanisms ( Fig. 51.1 and Box 51.1 ).

Classification

Generally, nonunions have been pathologically classified into two types : hypervascular and avascular , the distinction of which is easily made with a T99 bone scan. The orientation of the fracture line plays a role, and hence, nonunion of the proximal ulna distal to the insertion of the medial collateral ligament carries a better prognosis for reconstruction because the articular surface of the trochlear notch is intact. In fact, fractures less than 5 cm distal to the tip of the olecranon carry a poorer prognosis for healing. Treatment of nonunions associated with instability ( Fig. 51.2 ) may require ligament repair or reconstitution.

Although not formally classified, several additional features must be considered: (1) infected nonunion, (2) status of the joint, (3) resorption or bone loss, and (4) presence or absence of deformity at the nonunion.

Treatment Options

Indications

Asymptomatic nonunion with adequate elbow joint function requires no active treatment ( Fig. 51.3 ). For symptomatic nonunion, the goals of treatment are simply to restore function.

Treatment of Infected Nonunion of the Olecranon

Myocutaneous, local flexor carpi ulnaris muscle flaps and vascularized fibular bone grafts have been used successfully in the treatment of infected nonunions. Shortening may be required and is facilitated if the radial head is absent. Staged procedures are most commonly employed. An articulated external fixator is the most effective means of immobilization until soft tissue coverage and control of the infection can be achieved.

Nonunion With Minimal Articular Damage

Electrical stimulation

If there is minimal displacement and alignment is acceptable, electrical stimulation might be considered. This noninvasive method can be used on an outpatient basis ( Fig. 51.4A,B ). However, the expense, the need to immobilize, and the lack of predicable outcome has resulted in this option losing favor over time. The authors believe electrical stimulation is not a viable treatment option for olecranon nonunions because of the prolonged immobilization and unpredictable response.

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