Introduction

A non-united fracture of the distal humerus threatens the function of the entire upper limb. The involved elbow joint may be stiff, or grossly unstable, painful and associated with peripheral nerve dysfunction.¹ The non-union will compromise function of either the ipsilateral shoulder, hand, or both.

While fractures of the distal humerus are uncommon (2–6% of all fractures),^2,3 the unique regional anatomy, with the articular surfaces supported by limited bone yet subject to substantial reactive joint forces in normal daily activities, presents significant impediments to successful surgical fixation and functional outcome.

In this chapter we will present a comprehensive approach to the assessment, classifications, surgical management and outcomes of the treatment of those fractures of the distal humerus that fail to heal.

Background/aetiology

As our patients live longer, the incidence of upper extremity fractures including those involving the distal humerus is increasing. In addition, what we are seeing are more complex fractures occurring at or distal to the olecranon sulcus and associated with osteoporotic bone. These factors are providing the surgeon with an increasing challenge to achieve stable internal fixation that facilitates bone healing without complication. It is also leading to more interest in the use of total elbow arthroplasty as a primary form of fracture treatment.⁴ Closed or open distal humeral fractures are also seen in younger patients associated with higher-energy injuries. In each of these situations failure of bone healing has become a well-recognized adverse sequela.⁵ Additional risk factors contributing to non-union include obesity, alcoholism and patient unreliability, as well as advanced osteoporosis.⁶

Presentation, investigation and treatment options

A patient with a non-united distal humeral fracture will present with a dysfunctional upper limb. Pain at the non-union site, lack of elbow mobility, instability, distal hand compromise due to postsurgical swelling or peripheral nerve dysfunction, together with loose or prominent prior internal fixation devices, are all reasons for the patient to seek medical attention.

Clinical evaluation includes a careful and thorough history of the original injury, surgical treatment, and any medical or postsurgical complications. The patient’s overall medical health, such as diabetes, tobacco usage or treatment for osteoporosis, represents important potential risk factors. It is also paramount to determine the patient’s pre-injury functional status, limb dominance, extent of independence and social support.

The patient’s physical examination involves a careful assessment of the entire upper limb. The mobility of the adjacent joints including the ipsilateral shoulder, forearm, wrist and hand may be compromised from prolonged immobilization, postsurgical swelling or peripheral nerve injury or compression. The latter is particularly relevant as ulnar nerve compromise is now well recognized as a sequela of elbow trauma and surgical reconstruction and may be the source of pain as well as motor and sensory dysfunction in the hand.¹

Examination of the affected elbow must document the location and extent of previous surgical incisions, the adequacy and compliance of the soft tissue envelope, and joint mobility and/or instability. A grossly unstable or flail non-union will prevent the patient from effectively lifting the forearm against gravity (Fig. 20.1).

Figure 20.1 An unstable flail supracondylar nonunion. (A) In neutral. (B) Inability to lift the arm due to the instability.

Owing to the disturbed local anatomy at the non-union site, standard radiographs of the elbow may not adequately define the morphology of the nonunion. While evaluation of the original fracture and/or postoperative radiographs will be helpful, these are not always available. The distal articular fragment(s) of the non-union may be flexed due to capsular contracture and appear on the radiographs to be anatomically smaller than in reality.⁷ In these situations, or when non-unions occur within the articular surfaces, 3-D CT imaging may be extremely useful.

Careful assessment of the patient’s disability, associated risk factors, pre-injury functional status, and type and location of the non-union will allow the surgeon to develop an individualized treatment plan best suited to the patient’s needs and surgeon’s confidence and experience.

Treatment options will include a hinged functional brace for patients too infirm for surgery or who do not wish to undergo an additional surgical procedure; realignment with internal fixation and capsular release, or total elbow arthroplasty.¹

Surgical techniques and rehabilitation

The tactics of surgical treatment of a distal humerus non-union will depend upon the location and morphology of the non-union. Non-unions may be classified as supracondylar, intra-articular, or combined extra- and intra-articular (Table 20.1).⁷

Table 20.1 Classification of distal humeral non-unions based upon anatomical location

Non-union at the supracondylar level

Patient positioning, either lateral decubitus or prone, is dependent upon the surgeon’s preference but it is important to be able to flex the elbow to more than 120° in order to facilitate both surgical exposure and radiographic control. The iliac crest is prepared in the event that autogenous bone graft is required.

We prefer using a sterile tourniquet, although some might avoid this owing to the potential length of the reconstructive procedure. A straight dorsal surgical incision provides extensile exposure; however, prior incisions must be considered and included if possible (Fig. 20.2 (video)).

Figure 20.2 A 57-year-old executive with 18-month history of a painful non-union. (A) Radiograph of the supracondylar non-union with broken plates. (B) Video. (C) Functional outcome.

The ulnar nerve must be carefully mobilized, preferably for at least 6 cm proximal and distal to the cubital tunnel. The nerve is commonly surrounded by fibrosis that will limit its normal excursion following elbow mobilization, unless sufficiently mobilized and placed into the surrounding soft tissues (Fig. 20.3).

Figure 20.3 Step-by-step surgical fixation of a supracondylar level non-union. (A) Extensile exposure and mobilization of the ulnar nerve. (B) Following olecranon osteotomy the distal fragment can be mobilized. (C) The anterior capsule and synovial non-union are debrided through the non-union site. (D) The capsule is elevated off the distal aspect of the humerus shaft. (E) The distal end of the humerus shaft is contoured into a ‘V’. (F) Provisional fixation is done with smooth K-wires. (G) Stable impaction of the two fragments. (H) The lateral implant is applied first. (I) Close-up view of the impacted two fragments secured with two plates. (J) Bone graft placed around the impaction site. (K) Anteroposterior (AP) and lateral X-rays at 1 year.

A non-union at the supracondylar level can be effectively exposed through a triceps split, by exposure on either side of the triceps, or through an olecranon osteotomy. Whatever the chosen approach, elevation of the olecranon from the distal humeral articular surface must be done with extreme caution to avoid avulsion of articular cartilage that has become adherent due to lack of movement at the joint surfaces. Unless a total elbow arthroplasty is to be considered, we prefer exposure through an olecranon osteotomy created with a chevron cut with the apex pointing distally.

Once the non-union site is exposed, the posterior elbow capsule must be completely excised to permit mobilization of the distal articular fragment as well as the ulnotrochlear joint. The anterior capsule is readily accessed through the non-union site and excision will permit full exposure of the fracture fragments. The synovial membrane must also be excised to facilitate a more vascular environment.

The distorted anatomy will inhibit correct alignment of the fracture and, to improve this situation, the fracture ends should be carefully debrided. More stable impaction of the two fragments can be achieved by creating a trough in the distal fragment into which the contoured distal end of the humerus can be impacted. Provisional fixation with large, smooth K-wires placed through the medial and lateral aspects of the distal joint will not impede the placement of the definitive plate and screws.

The techniques of plate fixation will vary considerably based on the size of the distal fragment, the extent of the underlying osteoporosis, as well as the type and availability of implants. Although anatomically shaped implants have been developed for the distal humerus, the often-distorted anatomy that occurs with non-unions will frequently require contouring of standard plates. A third plate has proven to be useful in cases where limited bone exists in the distal fragment particularly if it is only possible to achieve one screw purchase per plate.⁸ Given that there is often incomplete bony contact, cancellous iliac crest graft should be used to fill in areas of bony defect (Fig. 20.4).

Figure 20.4 A very distal non-union in a 38-year-old male with gross instability. (A) AP X-ray of the non-union. (B) AP X-ray following stable fixation with three plates. (C) Lateral X-ray post surgery. (D, E) Functional outcome.

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