Study Guide

Congenital Radial Head Dislocation

Key Points:

Most common congenital anomaly about the elbow
Typically presents in late childhood/adolescence with pain or decreased range of motion of the elbow/forearm
Surgical intervention may help with pain but is unlikely to result in a significant increase in range of motion

Description:

Congenital radial head dislocation is a deformity of the radial head which is present at birth. It is often bilateral, however, it can be unilateral. The direction of dislocation is usually posterior (65%) (Mardam-Bey, 1979).

Epidemiology:

While congenital radial head dislocation is rare, it is the most common congenital anomaly about the elbow. It can occur as an isolated condition or may be associated with other congenital extremity abnormalities like radioulnar synostosis, genetic mutations, or as part of a syndrome such as nail patella syndrome (Mardam-Bey, 1979; Bengard, 2012). It occasionally has a familial occurrence (Mardem-Bey, 1979).

Clinical Findings:

Patients are typically asymptomatic in their early years and often do not develop complaints until late childhood or adolescence (Bengard, 2012). If patients become symptomatic, complaints include limited range of motion of the elbow, limited forearm rotation, elbow pain, and a visible or palpable prominence on the lateral aspect of the elbow.

Imaging Studies:

With congenital radial head dislocation, the radial head is often abnormally shaped. In an anterior dislocation, the posterior border of the ulna is concave rather than its usual slightly convex shape. The radial head is also dome-shaped without a central depression (Miura, 1990). In a posterior dislocation, the radial head is elongated compared to normal with increased convexity of the proximal ulna. The capitellum may be hypoplastic and the ulna may be shortened (Mardem-Bey, 1979; Miura, 1990).

Treatment:

Treatment is typically nonsurgical. Surgical intervention can be helpful to decrease pain. Surgery, however has not been shown to significantly improve range of motion (Mardam-Bey, 1979; Berngard, 2012). Surgical options include reduction of the radiocapitellar joint and reconstruction of the annular ligament, ulnar osteotomy with annular ligament reconstruction to realign the proximal radioulnar joint in young patients with mild deformity of the radial head, or radial head excision (Liu, 2015; Bengard, 2012). Risks associated with resection of the radial head include the possibility of developing wrist pain in the future (Bengard, 2012) and development of cubitus valgus or medial elbow pain (Miura, 1990; Kaas, 2011). Radial head excision prior to skeletal maturity can also result in proximal radius regrowth (Kelly, 1981).

Complications:

Complications after surgical intervention may include distal radio-ulnar joint pain and ulnar positive variance due to proximal migration of the radius, instability, cubitus valgus deformity, weakness, and regrowth of the proximal radius (Kaas, 2012).

References:

1.   Bengard MH, Calfee RP, Steffen JA, Goldfarb CA. Intermediate-term to long-term outcome of surgically and nonsurgically treated congenital, isolated radial head dislocation. J Hand Surg. 2012; 37A: 2495-2501.
2.   Kaas L, Struijs PAA. Congenital radial head dislocation with progressive cubitus valgus: a case report. Strat Traum Limb Recon. 2012; 7: 39-44.
3.   Kelly DW. Congenital dislocation of the radial head: spectrum and natural history. Journal of Pediatric Orthopedics. 1981; 1(3): 295-8.
4.   Liu R, Miao W, Mu M, Wu G, Qu J, Wu Y. Ulnar rotation osteotomy for congenital radial head dislocation. J Hand Surg Am. 2015; 40(0): 1769-1775.
5.   Mardam-Bey T, Ger E. Congenital radial head dislocation. J Hand Surg Am. 1979; 4(4): 316–320.
6.   Miura T. Congenital dislocation of the radial head. J Hand Surg Br. 1990; 15B: 477-81.