Introduction This article describes a technique in which measurements are obtained from radiographs of the contralateral, normal elbow to predict the magnitude of overlengthening resulting from use of a metallic radial head prosthesis.
Step 1: Obtain Bilateral Elbow Radiographs Obtain bilateral digital anteroposterior radiographs of the elbows that are orthogonal to the forearm in 45° of flexion and neutral forearm rotation.
Step 2: Perform Radiographic Measurements of the Contralateral, Normal Elbow Draw the angle on the radiograph of the normal elbow.
Step 3: Perform Radiographic Measurements of the Radial Head Implant Draw the same lines and angle and perform the same measurements on the implant radiograph.
Step 4: Calculate Radial Head Implant Length The virtual length of the native radial head implant (L-NRH) is subtracted from the virtual length of the radial head implant (L-RHI), which results in the magnitude of the radial head implant overlengthening in millimeters: (L-RHI) – (L-NRH) = overlengthening.
Results The radiographic measurement technique was validated in a cadaveric study.
What to Watch For Indications
Pitfalls & Challenges
This article describes a technique in which measurements are obtained from radiographs of the contralateral, normal elbow to predict the magnitude of overlengthening resulting from use of a metallic radial head prosthesis.
Clinical studies have demonstrated that radial head arthroplasty is safe and effective in restoring stability in the setting of comminuted unreconstructable radial head fractures associated with instability. Biomechanical studies have shown that insertion of a correctly sized metallic radial head implant can reliably restore elbow and forearm kinematics and stability to nearly normal levels1-3. A primary technical goal during radial head arthroplasty is placement of an implant that closely replicates the dimensions of the native radial head. Insertion of an implant that is too thick, which lengthens the radius axially or …
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