Background: The use of a metal radial head prosthesis to help
stabilize an elbow with traumatic instability is appealing because internal
fixation of multifragment, displaced fractures of the radial head is
susceptible to either early or late failure. The newer modular prostheses are
easier to size and implant, but their effectiveness has not been investigated,
to our knowledge.
Methods: Twenty-seven patients in whom a radial head replacement
with a modular metal spacer prosthesis had been performed to treat traumatic
elbow instability were evaluated with use of the Mayo Elbow Performance Index
(MEPI), the American Shoulder and Elbow Surgeons Elbow Evaluation Instrument
(ASES), and the Disabilities of the Arm, Shoulder and Hand questionnaire
(DASH). Radiographs were evaluated for arthrosis, periprosthetic radiolucency,
and heterotopic ossification.
Results: Seven patients underwent one or more subsequent operations
to treat residual instability, heterotopic ossification and elbow contracture,
ulnar neuropathy, or a misplaced screw. In two of these patients, the
prosthesis was removed as part of an elbow contracture release or to treat
infection. At an average of forty months postoperatively, elbow motion in the
entire group of twenty-seven patients averaged 131° of flexion with a
20° flexion contracture, 73° of pronation, and 57° of supination.
Stability was restored to all twenty-seven elbows, and twenty-two patients had
a good or excellent result according to the MEPI. Seventeen patients had
radiographic evidence of lucency around the neck of the prosthesis that was
not associated with increased pain, thirteen patients had clinically
inconsequential heterotopic ossification anterior to the radial neck, and nine
patients had radiographic changes in the capitellum.
Conclusions: An intentionally loosely placed modular metal radial
head prosthesis can help to restore stability in conjunction with repair of
other fractures and reattachment of the lateral collateral ligament to the
epicondyle in the setting of traumatic elbow instability with a comminuted
fracture of the radial head. While a prosthesis that is too large can cause
problems, lucencies around the stem of the intentionally loose prosthesis and
most changes in the capitellum do not appear to cause problems, at least in
the short term.
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors for a complete description of levels of evidence.