1 General considerations topenlarge
Stable restoration of radial length is usually important for elbow or forearm stability. If this cannot be achieved with ORIF, a proximal radius prosthesis will be necessary.
Prosthetic replacement for unreconstructable radial head fractures is indicated
- when the elbow joint is unstable
- with an unstable coronoid fracture
- with medial collateral ligament insufficiency or ulnohumeral instability
- after radial head excision with evidence of medial collateral ligament insufficiency or ulnohumeral instability
- with associated interosseous membrane injury (Essex-Lopresti injury)
Correct prosthesis size
Select the right prosthesis size to avoid over- or underfilling of the radiocapiteller joint which can cause restricted range of motion (too large and/or long prosthesis) or elbow instability (too small and/or short prosthesis).
Reconstruct the radial head with the excised fragments and choose the size of the prosthesis accordingly.
Cemented or uncemented prosthesis
The surgeon must choose between cemented and uncemented prosthesis, the latter being easier, but perhaps less stable.
2 Resection of the radial head topenlarge
Resect radial head fragments
Carefully resect all radial head fragments. Preserve the annular ligament for repair, if possible.
Trim the radial neck
Trim the radial neck to fit the prosthesis with of a small rongeur.
3 Replacement topenlarge
Opening the medullary canal
Carefully open the medullary canal with an awl to fit the prosthesis stem.
Trial insertion of the prosthesis
Insert the chosen prosthesis. Assess its length and stability. Cementing the prosthesis may be necessary for optimal stability, and can be determined now.
Avoid lengthening or shortening
To avoid lengthening and overstuffing of the radiocapitellar joint, or shortening and instability, the prosthesis should fit as follows:
The articular surface of the radial head prosthesis should be at the level of, or slightly proximal to the lateral edge of the coronoid articular surface.
The radius with prosthesis should match radiographs of the opposite (intact) forearm, to ensure correct length.
Check tracking of the prosthesis in flexion, extension, pronation and supination.
Check elbow stability.
If the elbow is stiff or unstable, change the size of the prosthesis accordingly.
Cement the prosthesis in place, if desired, and if its size and position are satisfactory.
If the annular ligament is ruptured, repair it with non-absorbable sutures.