A radial head fracture is a break at the top of the radius bone in your forearm, right where it meets the elbow joint. It is one of the most common elbow fractures in adults, typically caused by falling onto an outstretched hand. Many of these fractures are minor and heal well with nothing more than a sling and early movement, but the severity spectrum is wide. Comminuted (shattered) fractures, or those paired with ligament damage, can require surgery and months of rehabilitation to restore a functional elbow.
How It Happens and Who Gets Hurt
The classic mechanism is a fall on an outstretched hand. When your palm hits the ground, the force travels up through the wrist and forearm, driving the radius into the capitellum, the rounded knob at the lower end of the humerus. The radial head, caught between that impact force and the capitellum, cracks or shatters depending on how much energy is involved.1PubMed Central. Radial Head Fractures in Adults: A Narrative Review Low-energy falls from standing height account for a large share of cases, but high-energy trauma from sports collisions, cycling accidents, or falls from a height can produce more severe patterns.
One large epidemiological study identified 285 radial head and neck fractures, finding a median patient age of 43. There was no clear gender predominance overall, but the mechanisms differed: women more commonly sustained fractures from low-energy falls, while men were more often involved in higher-energy injuries.2PubMed. The epidemiology of radial head and neck fractures This pattern makes sense when you consider that older women are more likely to have reduced bone density, meaning a simple trip can be enough to break the radial head.
Why the Radial Head Matters So Much
The radial head is not just a passive part of the elbow. It acts as a secondary stabilizer against the elbow being pushed sideways (valgus stress), backing up the ulnar collateral ligament on the inner side of the joint.3Springer International Publishing. Biomechanics of the elbow It also helps transfer load between the forearm and the upper arm and keeps the forearm bones properly aligned along their full length. Cadaver studies have shown that removing the radial head reduces the elbow’s resistance to sideways force by roughly 30%, a meaningful loss of stability.4PubMed. Valgus stability of the elbow This is why surgeons take great care in deciding whether a damaged radial head can be repaired, needs to be replaced with a prosthesis, or can safely be removed.
Getting the Diagnosis Right
Standard X-rays are the first step after any elbow injury, but they miss a surprising number of radial head fractures. One study comparing X-rays to CT scans found that plain X-rays caught fractures with a sensitivity of only about 47%. When doctors also looked for a displaced fat pad on the X-ray, a sign that fluid has accumulated inside the joint, sensitivity improved to about 60%, but that still means roughly four in ten fractures went undetected by X-ray alone.5PubMed Central. Diagnostic accuracy of fat pad sign, X-ray, and computed tomography in elbow trauma: implications for treatment choices—a retrospective study
This is where CT scans earn their keep. In one series, CT revealed occult fractures in about 11% of patients whose initial X-rays appeared unremarkable. CT was also superior at identifying where a loose bone fragment had broken away from, which directly influenced the surgical plan.6PubMed. Multidetector computed tomography diagnosis of adult elbow fractures If you have a painful elbow after a fall, your X-ray looks “clean,” but you still cannot extend your arm fully or rotate your forearm without pain, a CT scan is a reasonable next step. That fat pad sign on the X-ray, even without a visible fracture line, should raise suspicion.
Classification and What It Means for Treatment
Surgeons most commonly use the Mason classification to categorize radial head fractures. In its modified form, it runs from Type I (a small, nondisplaced or minimally displaced crack) through Type II (a displaced partial fracture, usually a single fragment), Type III (a comminuted fracture where the head is shattered into multiple pieces), and Type IV (any radial head fracture combined with an elbow dislocation). The Mason system has been the standard for decades, but its reliability between different surgeons is only moderate. A large validation study found that when multiple observers graded the same fractures, overall agreement hovered around 50% for exact type assignment.7PubMed Central. Radial Head Fractures: Is the Mason Classification Still Effective Today? A Large-Sample Validation of Intra- and Inter-Observer Reliability This means the same fracture could be classified differently by two equally qualified surgeons, which is one reason why treatment decisions lean heavily on clinical judgment rather than classification alone.
When You Can Skip Surgery
The good news is that the majority of radial head fractures are Mason Type I, and these almost always heal without surgery. Treatment involves a brief period of splinting for comfort followed by early movement. “Early” really does mean early: one study found that patients who started moving their elbow within one to three days had better functional outcomes than those who waited a week.8The Open Orthopaedics Journal. Radial Head Fractures Long-term follow-up data on these nondisplaced fractures are reassuring. In one retrospective series, over 80% of patients had no complaints nearly two decades after their injury. A separate study of minimally displaced fractures managed without surgery reported zero complications and no need for later surgical intervention.9Journal of Orthopaedic Trauma. Minimally Displaced Radial Head/Neck Fractures (Mason Type-I, OTA Types 21A2.2 and 21B2.1): Are We “Over Treating” Our Patients?
The sticking point for many patients is the initial pain. Elbow fractures hurt, and the natural instinct is to keep the arm immobilized. But prolonged immobilization is the enemy here. Elbow stiffness sets in quickly, and the joint is notoriously difficult to loosen up once it locks down. So the rehab advice sounds counterintuitive but is well supported: move as soon as pain allows, even if movement is uncomfortable.
Surgical Repair With Screws or Plates
Mason Type II fractures, where a fragment is displaced but the head is not shattered, often call for surgical fixation. The goal is to restore the smooth, round articular surface so the radius can spin freely during forearm rotation. Surgeons typically use small screws, headless compression screws, or a low-profile plate, and the choice depends in part on where the fracture line sits on the radial head.
There is a “safe zone” on the radial head, a region that does not articulate with the ulna, where hardware can be placed without blocking forearm rotation. One study proposed subdividing Type II fractures based on whether the fracture allowed safe plate placement. In fractures where the plate had to be placed outside that safe zone, screw-only fixation produced better early range of motion and better functional scores than plating.10PubMed. Is the ‘safe zone’ identified in preoperative computed tomography helpful for choosing optimal implant for fixation of radial head fracture? The practical takeaway: if your surgeon recommends screws instead of a plate, it may be because the fracture pattern simply does not accommodate a plate well.
When the Head Cannot Be Saved
Mason Type III fractures, where the radial head is too fragmented to reconstruct, leave two main surgical options: remove the pieces entirely (radial head excision or resection) or replace the head with a metal prosthesis (radial head arthroplasty).
Radial Head Excision
Removing the radial head was once the go-to approach for severe fractures, and it remains appropriate in select cases, particularly isolated fractures where the surrounding ligaments are intact. Long-term follow-up studies show that many patients do well functionally. In one series, osteoarthritic changes appeared on imaging in about half of patients but were generally not clinically relevant.11PubMed. Resection arthroplasty for radial head fractures: Long-term follow-up However, the procedure is not without drawbacks. The proximal radius tends to drift upward over time (proximal migration), and the remaining stump drifts out of alignment with the capitellum. Excision greater than about 2 centimeters results in more drift, and patients whose original injury included an elbow dislocation had worse functional outcomes.12PubMed. Proximal radial drift following radial head resection Predicting reliably who can tolerate radial head excision without developing problems remains difficult.13PubMed Central. Delayed Proximal Migration of the Radius Following Radial Head Resection for Management of a Symptomatic Radial Neck Nonunion Managed with Radial Head Replacement: A Case Report and Review of the Literature
Radial Head Replacement
Prosthetic replacement has become the preferred option for comminuted fractures, especially when ligament damage means the elbow needs every bit of stability the radial head provides. In a comparative study, patients who received a prosthesis scored higher on functional outcome measures than those who had the radial head simply removed, and they showed less osteoarthritis on X-rays over time.14PubMed Central. Long-term Outcomes after Primary Radial Head Resection Arthroplasty vs. Acute Radial Head Resection vs. Secondary Prosthetic Removal in Comminuted Radial Head Fractures
Getting the prosthesis height exactly right is critical. An implant that sits even slightly too tall (“overstuffing”) dramatically increases the contact pressure on the capitellum, roughly doubling it compared to normal, which can cause pain and accelerated cartilage wear. An undersized implant, by contrast, reduces capitellar pressure but may not adequately stabilize the joint.15PubMed. Effect of Radiocapitellar Joint Over/Under Stuffing on Elbow Joint Contact Pressure This precision challenge is one reason prosthetic replacement remains a technically demanding procedure.
Long-term data out to about 12 years show that prosthetic replacement provides durable pain relief and good functional scores, but radiographic changes are common. One study at an average follow-up of about 12 years found capitellar erosion in 60% of cases, heterotopic ossification in 60%, and humeroulnar arthritis in 55%, though most patients still reported low pain levels and functional scores in the good-to-excellent range.16PubMed. Long-term outcomes of radial head arthroplasty for complex radial head fractures In other words, the X-ray often looks worse than the elbow feels.
Complex Injury Patterns to Watch For
A radial head fracture does not always happen in isolation. Two associated injury patterns are especially important because missing them changes outcomes dramatically.
The Terrible Triad
The elbow’s “terrible triad” consists of an elbow dislocation, a radial head fracture, and a fracture of the coronoid process (the bony hook on the ulna that helps lock the elbow in place). This combination is notorious because it strips the elbow of its primary and secondary stabilizers simultaneously, leaving a profoundly unstable joint. Surgery follows a specific protocol: repair the coronoid, fix or replace the radial head, and repair the lateral ligament complex. If the joint is still unstable after that, the medial ligament may also need repair, and sometimes an external fixator is applied temporarily.17PubMed Central. Outcomes after terrible triads of the elbow treated with the current surgical protocols. A review With modern surgical protocols, outcomes are generally favorable: at an average of about two and a half years post-surgery, patients in a review had a flexion arc averaging about 111 degrees and functional scores in the good range.18PubMed. Surgical treatment of terrible triad of the elbow
The Essex-Lopresti Injury
This is the one that surgeons genuinely worry about missing. An Essex-Lopresti injury combines a radial head fracture with disruption of the interosseous membrane (the sheet of tough tissue connecting the radius and ulna along the forearm) and a dislocation at the wrist end of those two bones.19PubMed Central. A historical perspective on the Essex-Lopresti injury It is rare but easily missed in the acute setting because attention focuses on the obvious elbow injury. If the interosseous membrane tear is not addressed, the radius migrates upward over time, leading to chronic wrist pain, forearm discomfort, and progressive dysfunction. When caught late, reconstruction of the interosseous membrane using a tendon graft can help, but outcomes are better when the full extent of injury is recognized early.20PubMed. Interosseous membrane reconstruction for the Essex-Lopresti injury If you have a radial head fracture and also notice wrist pain on the same arm, make sure to tell your doctor. That wrist pain is the clue.
Complications That Can Follow
Even with good treatment, several complications deserve mention.
Stiffness is the most common problem after any elbow injury. The elbow joint has a tendency to scar down and lose motion, and the worse the initial injury, the greater the risk. When stiffness becomes severe enough to interfere with daily life, surgical release (arthrolysis) combined with radial head arthroplasty can be effective. One study showed that patients went from a flexion arc of about 34 degrees before surgery to about 109 degrees at three years, and those improvements held steady over eight years of follow-up.21PubMed. Long-term outcomes of open arthrolysis combined with radial head arthroplasty for post-traumatic elbow stiffness: results are durable over 8 years
Heterotopic ossification, where bone forms in the soft tissues around the joint, is another recognized complication, particularly after prosthetic replacement. There is debate about whether routine prevention with anti-inflammatory medications is worthwhile. Some authors recommend it given the negative effect heterotopic bone can have on elbow motion, though the evidence base is limited.22Journal of Orthopaedics. The clinical implications of heterotopic ossification in patients treated with radial head replacement for trauma: A case series and review of the literature
Nonunion and avascular necrosis are less common but more serious. The blood supply to the radial head arrives through a few small arteries that can easily be disrupted by the fracture itself. If blood supply is lost, the bone fragment dies, preventing healing and sometimes requiring later excision or replacement.23PubMed Central. Radial neck fracture nonunion: A case report and novel fixation technique
Osteoarthritis After Radial Head Arthroplasty
Patients who receive a radial head prosthesis often develop some degree of arthritis around the elbow over the years. One study found arthritis visible on X-rays in the humeroradial compartment in about 72% of cases and in the humeroulnar compartment in about 56%.24PubMed. Post-traumatic elbow osteoarthritis after radial head arthroplasty: Prevalence and risk factors Longer immobilization after surgery, poor implant positioning, and signs of instability on early post-operative X-rays all correlated with more arthritis. This reinforces two themes that run through the entire management of these fractures: get the implant position right, and start moving the elbow as soon as safely possible.
Rehabilitation and Getting Motion Back
Whether your fracture is treated with or without surgery, rehabilitation follows the same principle: early controlled motion wins. A study comparing three different early mobilization protocols confirmed that patients who moved sooner had better range of motion, better strength, and better functional scores than those who were immobilized, with the differences being especially pronounced in displaced fractures.25Journal of Orthopaedic Trauma. Comparison of Early Mobilization Protocols in Radial Head Fractures The trade-off is more pain in the first few days, but that early discomfort pays off in long-term function.
Rehabilitation typically progresses from gentle active range-of-motion exercises (bending, straightening, rotating the forearm) to progressive strengthening over six to twelve weeks, depending on the fracture severity and treatment. Most people with Type I fractures return to full activity within a few weeks. Surgically treated fractures take longer, and complex injuries with ligament repair may require three months or more before you are cleared for unrestricted use.
When the Patient Is a Child
Radial head and neck fractures in children account for up to about 14% of all pediatric elbow fractures, but the clinical picture differs from adults in important ways. Children’s bones are more pliable, so the fracture pattern tends to involve angulation and tilting of the radial neck rather than comminution of the head itself. Up to 39% of these pediatric fractures come with a second, associated fracture that can be easy to overlook on initial X-rays.26PubMed Central. Diagnosis, treatment and complications of radial head and neck fractures in the pediatric patient Children also have a growth plate (physis) at the proximal radius, and damage to it can affect future arm growth. Treatment thresholds are more forgiving than in adults: angulation under 30 degrees and displacement under 50% is generally accepted as likely to remodel on its own as the child grows. Beyond those limits, reduction is warranted.
3D-Printed Custom Implants
One of the challenges with standard off-the-shelf radial head prostheses is that the radial head varies considerably in size and shape from person to person, and a mismatch can lead to overstuffing or poor joint congruence. Researchers have begun using 3D printing to create patient-specific titanium implants based on a mirror image of the patient’s healthy opposite elbow. Early multi-center results have been encouraging: in one prospective study, every implant showed good congruence with the capitellum and ulna intraoperatively, and no cases of capitellar erosion, overstuffing, or implant loosening were seen during the follow-up period.27PubMed. Radial head replacement with the 3D-printed patient-specific titanium prosthesis: Preliminary results of a multi-centric prospective study These are still preliminary data with relatively short follow-up, but the concept addresses one of the persistent technical frustrations of conventional arthroplasty: trying to match a standardized implant to a highly variable anatomy.