Principle-Based Internal Fixation of Distal Humerus Fractures


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HISTORICAL PERSPECTIVERestoration of painless and satisfactory elbow function after a fracture of the distal humerus requires anatomic reconstruction of the articular surface; restitution of the overall geometry of the distal humerus and stable fixation of the fracture fragments allow early and full rehabilitation. 1–7 Although these goals are now widely accepted by the orthopedic community, they may be technically difficult to achieve, especially in the presence of substantial osteoporosis or comminution. 7The guidelines proposed by the AO/ASIF group are considered, by most, to represent the standard technique for fixation of distal humerus fractures. 5,7 Their recommended technique includes fixation of the articular fragments with screws and column stabilization and with two plates at a 90-degree angle to one another. 5,8,9 Unquestionably, the limiting factor of this technique is the difficulty associated with fixation of the distal fragments to the shaft. When this method fails, it is due to the nonunion at the supracondylar level, or stiffness resulting from prolonged immobilization that has been used in an attempt to avoid failure of fixation that had been inadequate. 7 Using these fixation techniques, different authors have reported unsatisfactory results in 20%–25% of patients. 1–6In an effort to increase the potential for optimal function after fixation of distal humerus fractures and to obtain reproducible stable fixation in the presence of osteoporosis or comminution, the authors of the current study have developed and used for the past 11 years a philosophy and technique based on principles that maximize fixation in the distal fragments and compression at the supracondylar level. The stability achieved has allowed us to routinely commence an intensive rehabilitation program 36 hours after surgery. Rehabilitation includes full active motion with no external protection.The following discussion expands on the general principles of our current approach to these fractures, the specific technical details, the postoperative program, and the potential complications.PRINCIPLESExposureAccurate reduction of the articular surface of the distal humerus requires good exposure, which can be achieved with either an olecranon osteotomy or the triceps reflecting anconeus pedicle (TRAP) approach 10 (Fig. 1). The latter allows wide exposure without the need for an olecranon osteotomy. This is especially important in older patients in whom elbow replacement procedures may be necessary. With the TRAP approach, the intact proximal ulna and radial head can be used as a template against which the distal humerus can be reconstructed. In addition, the potential complications associated with olecranon osteotomies are avoided, 2,11 and the innervation of the anconeus is preserved. 10 If an osteotomy is performed, we preapply a Mayo Clinic Congruent Olecranon Plate (Acumed, Beaverton, OR), which is then removed and reapplied after fixation of the distal humerus (Fig. 2C).ReconstructionArticular surfaceThe articular surface of the distal humerus should be reconstructed anatomically, unless bone is missing. If bone is missing, two important principles should be taken into consideration. First, the anterior aspect of the distal humerus is the critical part of the articulation that needs to be fixed in order to have a functional joint; reconstruction of the posterior half is important, but not as critical. Secondly, stability of the articulation requires the medial trochlea and either the lateral half of the trochlea or the capitellum. Thus, the medial trochlea is essential to obtain a stable and well-aligned joint.The articular surface is fixed provisionally with small, smooth Kirschner wires. In addition, or alternatively, very small (0.035 in., 0.045 in.

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