Fig. 26.1
Fractures of the distal humerus, basing on AO classification [12], in which, in low-demand patients, the prosthesis is indicated
26.2.2 DHH
This prosthesis is indicated in unreconstructible fractures of the distal humerus when the following two conditions are met:
Integrity or stable fixation of the medial and lateral humeral columns with presence/validity of the medial collateral ligament (MCL) and of the lateral ulnar collateral ligament (LUCL)
Integrity of the coronoid and of the radial head
26.3 Contraindications
The main contraindications for a prosthetic implant in the elbow are critical wounds, open fracture, history of previous joint infection, neurological or vascular diseases, and muscle deficiency of the elbow flexors and/or extensors.
Other contraindications are a noncompliant patient (who would be unable to follow a rehabilitation program and to respect the limitations in the use of the elbow, most of all in TEA implants) and immunosuppression or immunodeficiency.
26.4 Surgical Technique
In the authors’ preferred technique, the patient is placed in supine position, with the arm above the chest (the lateral position is preferred sometimes if an ORIF of both columns is planned).
During the anesthesia procedure, intravenous antibiotic is administered (2 g of cefazolin or 600 mg of clindamycin in case of allergy to cephalosporins).
A sterile tourniquet is placed at the arm. Under regional or general anesthesia, a posterior median skin incision is performed.
The ulnar nerve is protected and widely isolated for the possible anterior transposition. The key point of this technique is the triceps management that the authors carry out according to the following diagram.
26.4.1 TEA
More followed method: triceps-sparing approach (Fig. 26.2)
Fig. 26.2
Triceps-sparing approach (Designed by School of Anatomical Drawing of Rizzoli Orthopaedic Institute)
The removal of bone fragments creates enough space for all the steps of the prosthetic implant, in both the humeral and the ulnar side (this is the most uncomfortable passage of the implant). By this method, the triceps remains intact, and the first phase of the rehabilitation is quicker and more effective.
Alternative methods: triceps splitting, triceps reflecting
The use of these techniques depends on the surgeon confidence, but splitting and reflecting are mainly indicated in case of prosthesis implant in degenerative diseases.
26.4.2 DHH
Conservation of the medial and lateral collateral ligaments is mandatory.
More followed method: triceps-sparing approach
This technique combines the advantages of leaving the extensor mechanism intact with an adequate exposure of both humeral columns for the plating needs.
TRAP approach (Fig. 26.3)
Fig. 26.3
TRAP approach (Designed by School of Anatomical Drawing of Rizzoli Orthopaedic Institute)
The authors prefer this technique to olecranon osteotomy, if a wide exposure of the columns is needed for their fixation.
Once the bone surface is exposed, the fracture pattern is evaluated, and the bone fragments are recovered and used to determine the size and the depth of the prosthesis; the depth of the humeral component is evaluated by the flange of the implant staying on the roof of the coronoid fossa.
A radial head prosthesis is implanted only in case of degenerative arthritis, but usually the proximal radius is conserved. The ulna is prepared with dedicated rasps and reamers, after the resection of the olecranon tip, to improve direct access to the medullary canal.
The trial components are very useful to check the implant alignment and the articulation in TEAs and to verify the feasibility of column fixation and of collateral ligament repair in DHHs.
The cementation technique is another key point of this surgery. After a careful canal lavage, the authors prefer the use of bony cement restrictors in the ulna and a plastic cement restrictor in the humerus to obtain a correct pressurization. Antibiotic-loaded cement is inserted under pressure by a cement gun with a thin nozzle (which can be cut in the suitable length). Cementation should be performed with the elbow in extension. When the prosthesis is correctly in place, a thin bone graft is inserted between the flange and the anterior humeral cortex.
In linked TEAs, if possible, tensioning of the collateral ligaments should be carried out, to improve the soft tissue balance and to reduce the load stress on the system.
In DHHs, the reconstruction of MCL and LUCL is mandatory. A correct reconstruction of the columns is necessary and is performed exploiting the hole (if available, like in Tornier Latitude implant) of the articular component. If a TRAP approach has been done, the anconeus is strongly sutured, and the triceps-olecranon contact is recreated by transosseous stitches with high-resistance sutures (Figs. 26.4, 26.5, 26.6 and 26.7 : case and surgical technique).
Fig. 26.4
Distal humeral fracture 3D CT scan images (anterior and posterior visions)
Fig. 26.5
DHH in situ with triceps-sparing approach. Tr. triceps dislocated, O. olecranon, MCL medial collateral ligament, RH radial head, LCL lateral collateral ligament
Fig. 26.6
ORIF of medial column, triceps in anatomic position. MC medial column, Ul ulnar nerve, Tr triceps
Fig. 26.7
Elbow X-rays after 1 year: DHH, plate for medial column reconstruction and suture anchor for LCL reconstruction
The ulnar nerve, if conflicting with the prosthesis, is anteriorly translocated, and the skin is closed in layers over two drains.
26.5 Postoperative Care
At the end of the surgical procedure, an elbow splint is placed preferably in extension. In case of wound problems, few days of rest from kinesis are indicated.
If a triceps-sparing approach has been performed, active extension and flexion can be immediately allowed.
If the triceps has been detached (TRAP approach), it should be protected by a splint in flexion for 4 weeks performing exercises in active flexion and passive or gravity-assisted extension, avoiding a flexion over 100°.
Usually, in linked TEA, the passive movement in flexion and extension begins the day after the operation and is progressively increased. This movement can be performed by a therapist or by a CPM machine. The patient is also taught how to perform self-assisted exercises in flexion, extension, pronation, and supination, using the contralateral arm.
In DHH, the rehabilitation must be more careful, avoiding varus and valgus stress on the reconstructed collateral ligaments, so the preferred protocol includes only self-assisted mobilization in flexion, extension, pronation, and supination after a detailed explanation of the exercises to do and of the movements to avoid. After 3 weeks of full-time splinting (with the only exceptions of self-assisted mobilization, wound care, suture removal, and personal hygiene), the rehabilitation program begins with passive and then active movement.
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