Lateral Collateral Ligament Insufficiency

Trauma

The LCL complex may be damaged as a result of trauma to the elbow, resulting in elbow dislocation, fracture–dislocation, subluxation, or ligamentous sprain ( Box 71.1 ). McKee et al. reported on the soft tissue injury patterns identified in 10 dislocations and 52 fracture–dislocations treated surgically. The LCL complex was disrupted in all cases; proximal avulsion was the most common failure mode, followed by midsubstance rupture. The common extensor-supinator group was injured in 66% of the cases. The anterior bundle of the medial collateral ligament was injured in approximately 50% of the cases. Less severe injuries causing dislocation or an elbow sprain (usually hyperextension or varus stress) may also damage the LCL complex if they place substantial strain on the ligament fibers. Occasionally, ligamentous disruption occurs through bone as an avulsion fracture of the crista supinatoris, and it may be associated with impaction fractures of the posterior aspect of the capitellum.

When injured, the medial collateral ligament seems to heal without residual clinically significant medial-sided instability in most patients. On the contrary, persistent lateral-sided instability seems to be more frequent, but the reasons are unclear. It may be related to a decreased healing potential, as seen in other anatomic locations such as the lateral side of the knee joint; the constant tensile gravitational loads imposed on the injured lateral side with elbow use; or the more common association with additional injuries, such as radial head or coronoid fractures. Lateral collateral ligament insufficiency should be suspected in patients with recurrent dislocation, subjective instability, lateral-sided pain, and a history of elbow trauma.

Chronic Attrition

Chronic attrition secondary to repetitive valgus stress is a well-known mechanism leading to medial collateral ligament insufficiency. Chronic attrition of the LCL complex may occur in rare situations such as long-term crutch-walkers (paraplegics, poliomyelitis). Posttraumatic or congenital cubitus varus deformity is recognized as a risk factor for chronic attrition of the LCL complex and tardy posterolateral rotatory instability. With varus malalignment, triceps contraction has been hypothesized to force posterolateral rotatory subluxation and eventually lead to attenuation of the LCL complex. In addition, one cadaveric study has shown increased strain on the LCL complex with more than 25 degrees of varus deformity and lateral joint line opening with more than 20 degrees of varus deformity. In this setting, corrective osteotomy should be considered as an adjunct to lateral collateral ligament reconstruction to prevent failure. Insufficiency of the lateral collateral ligament has also been identified in patients with tennis elbow and no prior surgery ; insufficiency in this setting may be secondary to ligamentous involvement by the same pathologic process affecting the common extensor group or the detrimental side effects on collagen fibers of repeated steroid injections.

Iatrogenic Injury

Inadvertent damage of the lateral collateral ligament may occur during surgical procedures on the lateral side of the joint. Surgical treatment of tennis elbow may compromise the LCL complex if the release or débridement of the common extensor origin is too extensive, especially when the lateral epicondyle is denuded off soft tissues. Exposure of the radial head or capitellum for fracture fixation or chronic reconstruction may also jeopardize the LCL complex, especially when Kocher's interval is used, or the joint needs to be subluxed or dislocated in order to complete the surgical procedure. Special attention is required when performing surgery on the lateral side of the elbow joint to avoid damage to the LCL complex. Formal repair of the damaged ligament should always be part of the wound closure.

Presentation

The clinical expression of LCL complex insufficiency varies considerably depending on the etiology, severity, associated pathology, previous surgery, and activity level ( Box 71.2 ). Some patients may complain of recurrent episodes of frank elbow dislocation. However, patients most commonly complain of more subtle symptoms, including lateral-sided elbow pain, mechanical symptoms (clicking, catching, snapping, locking), or subjective instability. Patients with ligamentous insufficiency after a fracture–dislocation may present with more severe pain or stiffness secondary to the associated injuries. Commonly, most patients with LCL complex insufficiency report a previous history of trauma or surgery. In patients with previous surgery, it is important to determine if the preoperative symptoms were corrected by the surgery, or if on the contrary, surgery had no effect or occasioned a whole new constellation of symptoms.