Hemiarthroplasty of the Distal Humerus



Hemiarthroplasty of the Distal Humerus


Rick F. Papandrea


Editor’s note: At the time of publication, the use of a hemireplacement is considered as an “off-label” identification by the FDA. The material is being presented as we find the concept has merit.



INTRODUCTION

Like many orthopaedic procedures, hemiarthroplasty is an old idea that has gained resurgence because of improved implants and a better understanding of the indications and related pathology. The reemergence of this technique had been possible due to the availability of anatomically shaped distal humeral components. These components are either the humeral component of an unlinked total elbow arthroplasty system (Sorbie-Questor, Wright Medical, Arlington, TN) or a custom component (spool) for a convertible elbow arthroplasty (Latitude, Tornier, Saint-Ismier, France). Currently, there is no dedicated hemiarthroplasty for the distal humerus, nor is there commercial support for using the available implants in this manner. Furthermore, unfortunately, at the time of this publication, neither of the above designs, the use of which is reported here, is currently available for this purpose in the United States.

In the United States, the FDA (Food and Drug Administration) approves implants for marketing for specific purposes. Both of the available implants have not been approved for use in hemiarthroplasty. This means that use of the implants for hemiarthroplasty is considered “off-label.” It is legal and ethical to utilize implants in an off-label manner, but the surgeon should disclose this information to the patient. The companies, on the other hand, cannot advertise or promote such use of these implants.

Hemiarthroplasty can be utilized for both acute and chronic conditions. If there is any way to reconstruct a joint with native tissue, this is preferred to prosthetic reconstruction. Prosthetic reconstruction of the elbow should be considered when all other nonimplant options have been exhausted or deemed inappropriate.

The role of hemiarthroplasty is developing. It can fill the void between reconstruction and total elbow replacement. The role of interposition prior to prosthetic arthroplasty is debatable and will not be covered.





PREOPERATIVE PLANNING

One should be certain that there are no concomitant injuries that would affect the outcome of a hemiarthroplasty. As noted above, any history of infections or medical history that may influence the risk of infection should be investigated.



  • Previous operative notes should be reviewed, any existing hardware needs to be considered, and appropriate equipment to remove existing hardware, if necessary, should be available.


  • The nerve function of the limb should be documented, and the soft tissue envelope needs to be examined to ensure that standard incisions are appropriate or alternative approaches can be carried out.


  • Proper imaging may be the most important aspect of the preoperative planning. Standard radiographs may be enough to determine that a hemiarthroplasty is appropriate and carry out the procedure. Oblique or traction views may add information.

At times, the determination of appropriate reconstruction for a distal humerus fracture or chronic condition may require a CAT scan to determine if the proximal radius and ulna are involved in such a way to preclude hemiarthroplasty, or if an injury cannot be reconstructed without nonprosthetic methods. We have found that 3D images offer a much more precise understanding of the pathology.

Note: As long as the axial data obtained from the CAT scan are available in DICOM format, the treating clinician may create 3D images using open source software (1).


SURGERY

Patient positioning can be either supine or lateral. Lateral positioning is carried out with an arm positioner that supports the brachium. If a supine position is chosen, and no arm table is utilized, an over-the-body support may minimize the need for additional assistance during the procedure.

Note: This author prefers to use the supine position, with a commercially available arm positioner, and no hand table. This allows unrestricted use of a small C-arm for imaging. A small “bump” of folded surgical bowels will lift the shoulder to aid in draping and prepping. Unless there is proximal hardware or fracture that requires posterior dissection of the radial nerve, a nonsterile tourniquet is placed as high on the brachium as possible.

A standard posterior skin incision to one side of the olecranon is typically utilized. Full-thickness skin flaps are elevated medially and laterally. The ulnar nerve needs to be identified and “controlled” prior to mobilizing the medial flap too far.

Note: Previously operated elbows may or may not have a transposed nerve. “Assume nothing.” A nerve that has been transposed may take a tortuous course coming back upon itself due to the additional length of nerve afforded by its nonanatomic position.

Once safely identified, the nerve should be dissected to allow a subcutaneous transposition (Fig. 34-2).

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Jun 14, 2016 | Posted by in ORTHOPEDIC | Comments Off on Hemiarthroplasty of the Distal Humerus

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