Total Elbow Arthroplasty



Total Elbow Arthroplasty


Peter Johnston, MD

Matthew L. Ramsey, MD


Dr. Ramsey or an immediate family member has received royalties from Integra LifeSciences and Zimmer; serves as a paid consultant to or is an employee of Integra LifeSciences and Zimmer; has received research or institutional support from Integra LifeSciences and Zimmer; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons, the Philadelphia Orthopaedic Society, the Rothman Institute, and the Rothman Specialty Hospital. Neither Dr. Johnston nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.



INTRODUCTION

A functional, pain-free elbow joint is dependent on the integrity of the ulnohumeral articulation. Diverse pathology exists that ultimately leads to destruction of the ulnohumeral joint and manifests as painful motion, instability, or ankylosis. The degree of functional limitation is dependent on the severity of bony destruction and the involvement of soft-tissue structures, which vary with the underlying pathology.

Current total elbow arthroplasty (TEA) implant designs are categorized as linked (coupled), unlinked (uncoupled), and hybrid linkable. The decision to use a linked versus an unlinked implant is dependent on the underlying pathology, the adequacy of bone stock, and the integrity of the ligamentous soft-tissue envelope. Unlinked implants require joint stability and bone stock adequate to support the implant, narrowing the indications, but provide a theoretical decrease in stress across the prosthesis and lower loosening rates when compared with a linked joint. Unlinked implants are suitable for pathologies with intact supracondylar columns, minimal subchondral bony deformity, and competence of collateral ligaments. Linked implants are joined by a “sloppy hinge,” which allows slight movement in the varus-valgus and axial planes. Indications for linked implants are broader, including ligamentous deficiency and traumatic conditions with severe bone loss, which include acute fractures, established posttraumatic arthrosis, distal humeral nonunion, posttraumatic ankylosis, posttraumatic instability, and revision TEA. Hybrid linkable implants permit implantation in an unlinked fashion, taking advantage of the benefits of an unlinked implant, but can be easily converted to a linked implant if stability cannot be established at initial implantation or if instability becomes an issue remote from the index arthroplasty.


PATIENT SELECTION




PREOPERATIVE IMAGING

Standard radiographic evaluation of the elbow joint includes AP, lateral, and oblique radiographs (Figure 1). These views are usually sufficient to assess bone quality and the degree of bony abnormality, providing the surgeon with information guiding implant selection (linked versus unlinked) and sizing. Additionally, stress radiographs can be taken if there is a suspicion of ligamentous instability.

CT usually is not necessary in the preoperative workup of patients with underlying arthritides, but it can provide
the surgeon with additional information on joint or periarticular deformity. CT can be particularly useful in the acute fracture setting, in managing malunion or nonunion, or in cases with heterotopic ossification. MRI has a limited role in the preoperative diagnostic workup for TEA.






FIGURE 1 AP (A), lateral (B), and oblique (C) radiographs of the elbow of a patient with rheumatoid arthritis demonstrate joint destruction and cyst formation in the capitellum severe enough to consider total elbow arthroplasty.


Preoperative Evaluation

Prior to surgery, a detailed examination is performed with attention to the status of the overlying skin, prior incisions, contractures, limb alignment, joint stability, and flexion-extension arc. If prior surgery has been performed, the location of the ulnar nerve should be considered as well as the presence of ulnar nerve symptoms.


Preoperative Planning

Preoperative radiographs, any underlying pathology, and surgeon experience should guide the selection of a linked versus an unlinked implant. It is important to recognize that if an unlinked system has been selected, a linked system should be available in case it becomes apparent that an unlinked system will not stabilize the elbow. A linkable system allows easy conversion from an unlinked to a linked arthroplasty.