Radial Head Replacement: Solutions for Complex Elbow Injuries
Key Takeaway
This article provides essential research regarding Radial Head Replacement: Solutions for Complex Elbow Injuries. Radial head replacement is a surgical procedure indicated for complex radial head fractures not amenable to internal fixation, especially when accompanied by valgus instability due to medial collateral ligament insufficiency. It is also used for radial head fractures with concurrent distal radioulnar joint injury (Essex-Lopresti injury) or for instability following previous radial head resection.
A 45-year-old patient presents following a high-energy fall onto an outstretched hand. Radiographs show a displaced, comminuted radial head fracture. How do you assess the stability of the elbow, and what specific clinical features would make you abandon ORIF in favor of radial head replacement?
Candidate: I would assess for the "terrible triad" by checking for associated coronoid fractures or ligamentous instability. If the fracture is too comminuted to fix with stable internal fixation, I would replace it. I'd also look for Essex-Lopresti injuries, which absolutely require a radial head replacement to maintain the longitudinal axis.
Candidates often focus only on the bone. They fail to mention the 30% contribution of the radial head to valgus stability, the "drop sign" on lateral imaging, or the clinical urgency of repairing the LCL complex to prevent chronic instability.
I assess stability by ruling out the "Terrible Triad" (radial head + coronoid + LCL injury) and the "Essex-Lopresti" lesion (radial head + IOM/DRUJ injury). Indications for arthroplasty include: 1) Comminution (>3 fragments) where anatomic reconstruction is impossible, 2) Presence of an associated MCL or IOM tear (making the radial head a primary stabilizer), and 3) "Overstuffing" risks. I would confirm this on CT and intraoperative stress testing, ensuring no proximal migration or valgus laxity is present.
You have decided to proceed with a metallic radial head replacement. You are concerned about "overstuffing" the radiocapitellar joint. How do you technically verify the correct implant size intraoperatively?
Candidate: I would use the trial implant and check the range of motion. I want to make sure it doesn't feel too tight and that the patient has full flexion and extension. I'd also look at the X-rays to see if the radial head looks aligned with the capitellum.
This response is subjective. A high-scoring candidate must mention objective radiographic markers like the "drop sign," lateral ulnohumeral space widening, and the requirement for fluoroscopy to confirm the absence of overstuffing.
Overstuffing is prevented by: 1) Using the contralateral elbow as a templating baseline. 2) Intraoperative fluoroscopy: The "drop sign" (widening of the ulnohumeral joint space on lateral view) indicates an overstuffed implant. 3) Mechanical assessment: There should be no tension on the LCL repair, and a small instrument should pass freely through the lateral radiocapitellar interval. 4) The implant should move/track smoothly through the functional arc without creating a flexion contracture.
You are performing the approach for this radial head replacement. Describe your approach of choice and explain how you manage the Posterior Interosseous Nerve (PIN) at risk.
Candidate: I would use the Kocher approach, which uses the internervous plane between the ECU and the Anconeus. I would protect the PIN by keeping the forearm pronated during the surgery.
Ignoring the risks of the Kaplan approach. While Kocher is safer, failing to acknowledge that the Kocher approach requires detachment of the LCL origin—which must be repaired—demonstrates a lack of procedural planning.
I prefer the Kocher approach (internervous plane between ECU and Anconeus) because it is safer for the PIN than the Kaplan approach. To protect the nerve, the forearm must remain pronated, which winds the PIN away from the radial neck. I must remember that if I extend the Kocher approach proximally, I will encounter the LCL origin, which must be carefully detached and later reconstructed to maintain posterolateral rotatory stability.
