Case

A 36-year-old female with no pertinent past medical history presents to the ED for evaluation of a left arm injury. While walking her dog during today’s ice storm, the dog pulled at the leash and she slipped on the ice, falling on her outstretched left arm and tailbone. She reports severe, constant left elbow pain which is worsened by movement or palpation. She denies paresthesias or distal changes in coloration but is unsure of her ability to move the extremity secondary to pain. Imaging was obtained (Figure 1) and her left arm was placed in a temporary sling.

Discussion

Anatomic Function of the Radial Head:

The radial head articulates with the humerus at the elbow via the radiocapitellar joint (Image 2). During grip activity of the hand, the forearm and the wrist are stabilized by the transfer of load from the wrist and forearm to the elbow at the radiocapitellar joint. This articulation accounts for as much as 60% of the load transfer at the elbow and also helps the elbow resist external forces (with ligamentous support), preventing valgus instability. Therefore, any displacement of the radial head decreases the amount of surface area that may be used for load transfer and leads to decreased elbow stability.

Epidemiology & Etiology:

Radial head fractures commonly occur during falls when the patient lands on an outstretched hand with the forearm pronated and the elbow in extension. This mechanism of impact leads to an uncharacteristic amount of force transmission through the radial head at the elbow. These fractures account for nearly 4% of all fractures and approximately ⅓ of elbow fractures. Up to 39% of these fractures have other associated fractures or soft tissue injury- most commonly lateral collateral ligament injury, medial (ulnar) collateral ligament injury, elbow dislocation, or coronoid fracture. The likelihood of associated injuries increases with the severity of radial head fractures, graded by the Mason classification (8% in Mason I, 50% in Mason II, 75% in Mason III, and 100% in Mason IV). [5,7]

Fracture Classification:

Radial head fractures were initially classified by Mason in 1954 after a review of one hundred cases, including management and outcomes. This fracture classification was revised by Hotchkiss in 1997 with more specificity regarding the degree of displacement in relation to the need for surgical management and outcomes. The key to the evaluation of these fractures in the emergency department is the delineation of type I fractures from type II-IV, as the management of the former is non-operative and the majority of the type II-IV fractures are operative.

●      Mason type I

○      Minimally displaced fracture

○      No mechanical block to forearm rotation

○      Intra-articular displacement < 2 mm

●      Mason type II

○      Fracture displaced > 2 mm or angulated

○      Possible mechanical block to forearm rotation

●      Mason type III

○      Severely comminuted fracture

○      Mechanical block to motion

●      Mason type IV

○      Radial fracture with associated elbow dislocation

Evaluation:

Any patient presenting with an elbow injury and lateral tenderness suggestive of radial head fracture should undergo imaging, clinical evaluation for elbow instability, and evaluation for restriction to elbow motion. Anteroposterior and lateral radiographs should be obtained. A Greenspan view (modified lateral with the XR beam angled 45 degrees towards the radial head) may be obtained to remove the coronoid overlap. For injuries classified as Mason II-IV, computed tomography (CT) imaging may assist in further characterizing the fracture pattern, identifying associating injuries, and aiding in surgical planning.

All patients should undergo careful ROM assessment, even if only a Mason Type I fracture is suspected from imaging. When evaluating for elbow instability and mechanical blocks to elbow motion, it may be advantageous to aspirate the joint hematoma and inject the elbow joint with a local anesthetic to alleviate patient discomfort and facilitate proper evaluation. All patients should be evaluated for elbow flexion/extension, forearm supination/pronation, and varus-valgus laxity of the elbow. To proceed to nonoperative management, patients must have a flexion arc of 10-130 degrees and 70/70 degrees of pronosupination on gentle, passive ROM. [4,5,6,8]

Treatment and Outcomes:

●     Mason type I

○      Nonoperative

○      Managed with a period of brief immobilization for 24-48 hours following injury and conservative treatment (ice, sling, elevation) with early ROM as tolerated.

○      Orthopedic follow-up for re-evaluation of fracture healing. 97% successful in pain resolution and restoration of ROM.

●     Mason type II

○      Sometimes operative, depending primarily on blocks to ROM

○      Commonly treated with ORIF

○      Outcomes are very good if all associated injuries are addressed

●     Mason Type III

○      Operative

○      ORIF vs. radial head arthroplasty (prosthesis implantation vs. radial head resection)

○      Outcomes can also be good to very good with a return of stability and high patient satisfaction.

●     Mason type IV

○      Operative

○     Often requires radial head replacement (prosthesis implantation vs. radial head resection) > ORIF for good outcomes with regard to stability and patient satisfaction.

[1,5,7]

Articular Anesthetic Block of the Elbow:

Aspiration of the intra-articular hematoma of patients with radial head fractures (with an anesthetic block of the elbow) has been shown to not only facilitate ROM testing in ED following injury, but also to improve ROM in the recovery period for these patients. Up to 60% more patients were found to have full range of motion at four weeks post-injury if their hematoma was evacuated in the ED. Furthermore, for every 1 mL of fluid aspirated from the joint, 2 degrees of ROM may be regained. [3,4]

●      Step 1: Position the patient

○      Position the patient seated with the arm resting at 45 degrees of flexion.

●      Step 2: Sterile technique

○      Prep the skin with a high-grade antimicrobial agent such as chlorhexidine gluconate and drape for sterility.

○      Prepare two 10 cc syringes: one syringe filled with 1% or 2% lidocaine without epinephrine and another empty syringe for aspiration.

●      Step 3: Site selection

○      Palpate the lateral elbow and use a sterile pen to mark out three key landmarks which will form a triangle to guide joint penetration- the lateral epicondyle, the radial head, and the lateral portion of the olecranon (Figure 4). This area will form a triangular boundary for the soft tissue overlying the joint space. This is your needle entry point.

●      Step 4: Aspiration and injection

○      Use a 27G needle and your local anesthetic, create a wheal overlying the target site (left to clinician discretion), and then the joint may be approached with a large needle (18-21G).

○      The needle should enter the joint space easily and while the clinician maintains negative pressure, aspiration of a small to moderate amount of sanguineous/serosanguineous fluid should occur easily. After a sufficient amount of hematoma has been aspirated, the needle should remain in place while the syringe used for aspiration is replaced with the lidocaine-filled syringe.

○      5 cc of lidocaine may then be injected into the joint space for patient comfort and ROM testing.

[3,4,8]

Conclusions

In this case, imaging of the elbow demonstrated a minimally comminuted intra-articular fracture of the radial head. After receiving appropriate pain control in the ED, an examination of the elbow was able to be performed without joint aspiration which demonstrated a normal neurovascular exam and appropriate range of motion (ROM) of the elbow, forearm, and hand. This exam, in conjunction with her imaging findings, classified her fracture as a Mason type I fracture which allowed the patient to be discharged with conservative management, early active ROM, and planned outpatient follow-up with orthopedics. At six months follow-up, the patient demonstrated appropriate evidence of fracture healing on plain films (Image 4) and grossly regained ROM at the elbow. Our recommendations from this case review would be to consider hematoma aspiration and joint block for every patient with a radial head fracture, even those with Mason I fractures (as in this case), to encourage early and long-term restoration of ROM at the affected joint.

Author: Jeremiah Gress, MD is a second-year emergency medicine resident at Brown University/Rhode Island Hospital.

Faculty Reviewer: Jeffrey Feden, MD is an attending physician at Brown Emergency Medicine.

References

1. Harbrecht, A., Ott, N., Hackl, M. et al. Radiuskopffrakturen. Unfallchirurg 124, 153–162 (2021). https://doi.org/10.1007/s00113-020-00947-8

2. Hotchkiss RN: Displaced fractures of the radial head: Internal fixation or excision? J Am Acad Orthop Surg 1997; 5:1-10.

3. Johnston GW. A follow-up of one hundred cases of fracture of the head of the radius with a review of the literature. Ulster Med J. 1962 Jun 1;31(1):51-6. PMID: 14452145; PMCID: PMC2384652.

4. Morrey, Bernard F., Joaquin Sanchez-Sotelo, and Mark E. Morrey. Radial Head Fracture: General Considerations, Conservative Treatment, and Radial Head Resections. Morrey’s the Elbow and Its Disorders. Fifth edition. Philadelphia, PA, 2018. Print.

5. Wang JH, Rajan PV, Gokkus K, Shetty S. Radial head fractures. Orthobullets. https://www.orthobullets.com/trauma/1019/radial-head-fractures. Published September 4, 2021. Accessed February 14, 2022.

6. Tejwani, Nirmal C, and Hemang Mehta. “Fractures of the Radial Head and Neck: Current Concepts in Management.” Journal of the American Academy of Orthopaedic Surgeons 15.7 (2007): 380–387. Web.

7. Van Riet, Roger P et al. “Associated Injuries Complicating Radial Head Fractures : A Demographic Study.” Clinical orthopaedics and related research 441.441 (2005): 351–355. Web.

8. Zezo. The elbow and Forearm. Musculoskeletal Key. https://musculoskeletalkey.com/the-elbow-and-forearm/#F1-3. Published March 14, 2020. Accessed February 8, 2022.