Arthroscopic Radial Head Resection: Indications and Technique

Darryl K. Young

Graham J. W. King

Deformity of the radial head is usually the result of a posttraumatic or inflammatory process. It is also seen in the setting of congenital radial head dislocation. This deformity can lead to pain and stiffness referable to the radiocapitellar or proximal radioulnar joint incongruency and arthrosis. In this setting, radial head resection may be an effective treatment for appropriately selected patients. Radial head excision reduces impingement between the deformed radial head and the corresponding articulation with the capitellum or proximal ulna, thus improving forearm rotation and decreasing pain.

Radial head resection has been classically performed through an open arthrotomy (1). Arthroscopic radial head resection has only been described more recently (2, 3 and 4) but is gaining popularity. Although there is little evidence to support arthroscopic over open techniques, there are theoretical advantages. One of the primary advantages is less soft-tissue disruption, theoretically reducing the severity and duration of postoperative pain and stiffness. Another advantage is the improved intra-articular visualization, thus allowing the surgeon to address concomitant pathologies, such as synovitis, capsular contracture, osteophytes, or loose bodies.

It is worth emphasizing that radial head resection has very narrow indications. Surgeons treating patients with symptomatic radial head deformity should be well aware of the contraindications of radial head resection. In this chapter, we will outline the patients we feel are the ideal candidates for arthroscopic radial head resection. We will emphasize the appropriate preoperative evaluation, treatment alternatives, surgical technique, and “pearls and pitfalls” of managing these patients.

BIOMECHANICS AND PATHOANATOMY

The role of the radial head as a stabilizer of the elbow has been well established. Biomechanical studies have investigated the effect of radial head resection and replacement on the kinematics and stability of the elbow. The radial head has been demonstrated to be an important stabilizer in the setting of valgus instability due to medial collateral ligament (MCL) insufficiency (5, 6 and 7). Posterolateral rotatory instability (PLRI) (5, 8, 9 and 10) due to loss of tensioning of the lateral collateral ligament and proximal migration of the radius (11) due to deficiency of the interosseous membrane have also been reported following radial head excision. In addition, radial head excision results in increased loading of the ulnohumeral (UH) articulation due to altered elbow kinematics and the loss of load sharing by the radiocapitellar articulation. This may explain the high incidence of osteoarthritis, which is commonly reported after radial head excision (12, 13 and 14). Likewise, biomechanical evidence reveals that prosthetic replacement of the radial head offers beneficial stabilizing effects (5, 6 and 7, 15, 16).

The sum of these findings leads us to believe that, in most circumstances, the radial head should be preserved where possible and replaced after it is resected. This is particularly true in the setting of acute trauma where occult ligament injuries are common.

Arthroscopic radial head resection is usually performed in the setting of rheumatoid arthritis or posttraumatic arthritis. The posttraumatic arthritis often is associated with a previous radial head fracture. Although less common, radial head resection is occasionally performed for other conditions such as hemophilic arthropathy of the elbow and both congenital and acquired radial head dislocations. A fractured radial head can result in deformity of the radial head secondary to fracture malunion or osteophyte formation and joint derangement associated with progression of posttraumatic arthritis. Chronic inflammatory or hemophilic synovitis of the elbow can lead to enlargement and irregularity of the radial head. A hypertrophic or irregular radial head can impinge against the proximal ulnar facet acting as a mechanical block to forearm rotation. Likewise, there may be a mechanical block at the radiocapitellar joint affecting elbow flexion and extension.

CLINICAL EVALUATION

History

Patients with symptomatic radiocapitellar deformity often complain of pain and stiffness that is more pronounced
with pronosupination rather than elbow flexion and extension. Mechanical symptoms such as clicking, catching, or locking may be present as well. A history of prior elbow trauma or surgery and other treatment to date is essential to guide diagnosis and treatment. The past medical history can reveal the underlying disease process (inflammatory arthritis, posttraumatic arthritis, primary osteoarthritis, hemophilia, etc.).

Physical Examination

The physical examination starts with inspection of the elbow carrying angle, bony contours, and evidence of surgical scars. The range of motion of the elbow and forearm should be measured accurately with the use of a goniometer. Any motion deficits should be distinguished as having either a “soft” or a “firm” endpoint, which correlate with a soft-tissue cause or osseous impingement, respectively. In the setting of rotational stiffness, one should confirm that the proximal radius articular deformity is the impediment, since the distal radioulnar joint (DRUJ) may be contributing in some cases. For this reason, physical examination and imaging of the wrist are important.

The patient population that are candidates for radial head resection are prone to instability, particularly due to prior trauma or ligament attenuation secondary to chronic inflammation. It is important to evaluate for elbow and forearm instability since valgus, posterolateral rotational, and axial instability are contraindications to radial head resection. The examination for valgus instability includes the valgus stress testing, the “milking maneuver,” and the moving valgus stress test. The examination for PLRI includes the lateral pivot shift test, the posterolateral drawer test, and the supine and seated push-up tests. Although axial radioulnar instability is more difficult to detect on clinical examination, the presence of tenderness or dorsal prominence of the ulna at the DRUJ should raise the suspicion for this condition.

The location and function of the ulnar nerve should be assessed whenever elbow arthroscopy is planned. A previous ulnar nerve transposition will make standard percutaneous placement of medial portals risky. In this setting, open placement of the medial portals should be used to prevent iatrogenic nerve injury.

Imaging

Plain radiographs usually confirm the diagnosis of radiocapitellar joint derangement (Fig. 35.1). In addition to the standard AP and lateral views, a radiocapitellar view is often helpful to bring the radial head into profile. Radiographs of the wrist should be performed to ensure that there is no other cause of painful or limited forearm rotation, such as DRUJ pathology or radioulnar synostosis. Longitudinal radioulnar dissociation is best detected by bilateral wrist views to compare the ulnar variance with the contralateral normal side. If the diagnosis of instability is uncertain based on the physical exam, live fluoroscopic examination, and stress views should be performed to evaluate for valgus, varus, and axial instability.

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