1 Introduction topenlarge
Take care when approaching an apparently non-articular medial condylar fracture as these are unusual. Preoperative imaging, including computed tomography, can be used to identify associated articular fractures.
Screw fixation alone will only provide adequate stability for immediate active exercises when the bone quality is excellent, and the fracture is simple and non-fragmented.
In practice, screw fixation alone is used primarily in skeletally immature patients, who can be immobilized for 3-4 weeks in a cast without becoming too stiff.
Most medial condylar fractures in adults are fixed with a plate and screws to allow immediate active motion.
2 Open reduction topenlarge
Mobilize the fragment and clean the fracture site
Isolate and protect the ulnar nerve.
Open the fracture site by gentle retraction of the fragment.
Clean out the fracture by removing blood clots, loose pieces of bone, and any interposed tissue. Inspect the joint to ensure that no additional intraarticular fracture fragment was missed when examining the imaging.
Reduce the fracture.
Monitor fracture reduction by realigning the metaphyseal fracture lines.
Check the anterior and posterior fracture lines, including the articular surface.
3 Plate preparation topenlarge
Plate selection and preparation
Plate designs have evolved from straight, adjustable plates to precontoured locking plates and recently precontoured locking plates with variable angle (VA) screws.
The precontoured VA locking plates provide an ideal fit to the bone with typically no need for further adjustments. They also allow for optimal placement of locking screws and are therefore recommended.
Anatomic (precontoured) plates may be used, and do not require contouring.
If these are not available, a 3.5 mm reconstruction LCP may be used and contoured according to the anatomy.
If the plate does not go below the medial epicondyle, a transposition of the ulnar nerve may be considered.
A lag screw can be placed separately prior to plate positioning. Alternatively, all VA locking screws can be passed through the plate.
Alternative plate designs provide an embracing of the medial epicondyle with a precontoured plate. This allows a higher variation of screw trajectories, especially an ascending screw insertion.
It is recommended that the ascending screw is inserted first and the further distal screws in variable angles to avoid screw interference.
4 Provisional fixation topenlarge
The fracture is preliminarily stabilized with smooth K-wires at least 1.5 mm in diameter. The wires should be inserted carefully so that they do not hinder plate placement.
Provisional wires may be inserted through a plate screw hole, or adjacent to the plate to prevent their conflicting with plate placement.
5 Lag screw insertion top
Considerations for screw placement
The lag screw should be placed as distally as possible to ensure good compression of the articular surface fragments and minimal interference of the intended plate position. The screw should be as long as possible.
Drill the near fragment with a 3.5 mm drill to create a gliding hole.
Then drill the far fragment with a 2.5 mm drill.
Insert the screw and tighten to compress the fragments.
Depending on the stability provided by the lag screw the K-wires can then be removed.
6 Plate application top
Considerations for plate placement
The plate should be positioned on the medial ridge slightly dorsal to the intermuscular septum.
Due to the anatomy and/or the prominence of the screw head it may be necessary to bend the plate. This ensures an optimal plate fit and positioning of long screws through the articular block.
Preliminary plate fixation
The plate is positioned on the bone and preliminarily fixed with a cortical screw proximal to the fracture line. Typically, the elongated hole can be used. The elongated hole offers the option to fine tune the final plate position.
The quality of reduction and plate position should be checked with an image intensifier in two planes.
Distal screw insertion
Recent plate designs provide the option of either fixed angle or variable angle locking screws. The decision which type of screw should be used depends on the possible screw trajectory. Screws should be as long as possible. Care must be taken not to penetrate the joint surface.
Drilling for variable angle screws
Mount a variable angle funnel which allows the drill bit up to 15° of angulation. Drill the hole at the desired angle using a 2.0 mm drill bit. This step should be controlled under image intensification in order to obtain a proper screw trajectory.
Distal screw insertion
After length measurement a 2.7 mm variable angle locking screw is inserted and tightened using the 1.2 Nm torque limiter.
Further screws are inserted through the remaining distal plate holes depending on the fracture pattern.
Proximal screw insertion
Next, insert a 3.5 mm locking screw in the most proximal plate hole. Further proximal screws may be applied depending on the bone quality and fracture pattern.
7 X-ray control top
The final implant positions and fracture alignment are confirmed using image intensification.