The elbow is one of the most congruous joints in the body. Joint stability is provided by a combination of the bony architecture and the collateral ligaments and muscles. The lateral collateral ligament (LCL) complex plays a key role in elbow stability, preventing the proximal ulna and radius from subluxating as the supinated forearm is axially loaded. Trauma, usually dislocation, is the most frequent cause of disruption of the LCL complex. However, chronic varus load and steroid injections for epicondylitis have been described as possible causes of LCL insufficiency. After trauma has occurred, restoration of lateral soft tissue support can usually be accomplished by a direct repair of the lateral ligament and extensor tendon origins to the humeral epicondyle. In instances of recurrent dislocation or subluxation, temporally remote from the initial injury, a tendon graft may be needed.
The medial collateral ligament (MCL) resists valgus force and supports the ulnohumeral joint. Medial collateral instability is most commonly due to chronic attenuation of the medial ligament complex resulting from overhead throwing motions. It can also occur in javelin throwers, gymnasts, quarterbacks, and other athletes who use overhead throwing motions and exert a repetitive valgus stress across the elbow. When medial instability limits athletic participation and conservative care fails, a free tendon graft reconstruction is typically required.
Chronic Lateral Instability
Preoperative Evaluation
Chronic LCL insufficiency varies in its presentation. A patient may report a painful clunking and/or snapping of the elbow. Others will describe apprehension or weakness when reaching for an object with an outstretched hand, in varus load. Some may have episodes of frank giving way or apprehension, especially when the elbow is axially loaded in extension and supination. This can occur, for example, when one is pushing up from a chair. In this setting, the supinated radius and proximal ulna rotate laterally off of the distal humerus in a pattern termed posterolateral rotatory instability (PLRI) . Occasionally, unremitting lateral elbow pain is the patient’s chief complaint.
Physical Examination
Physical examination in patients with chronic PLRI is characteristically benign. Grip strength and range of motion are usually unaffected, although some extension deficit may be present. In the setting of chronic instability, minor discomfort may be present on palpation of the lateral elbow. Occasionally, a synovial fistula can be observed as a fluid collection about the lateral elbow.
Due to apprehension and guarding in a patient who is awake, it is often difficult to elicit frank posterolateral instability in the office, especially in muscular individuals. Subluxation of the elbow can be appreciated, however, with the appropriate provocative maneuvers. The elbow may be examined with a patient sitting or lying supine on a table. In the sitting position, one hand stabilizes the adducted humerus, with the fingers placed along the lateral ulnohumeral joint. While the elbow is partially flexed 40 to 45 degrees, the examiner’s contralateral hand loads the proximal forearm in supination with slight axial and valgus force applied. Instability is appreciated as gapping at the ulnohumeral articulation as the radius and ulna subluxate. This results in a posterolateral prominence as the radial head subluxates away from the capitellum. The ulnohumeral articulation can be reduced by pronation of the forearm and slight flexion of the joint. Reduction is occasionally accompanied by a palpable clunk.
Alternatively, the posterolateral rotatory apprehension (pivot shift) and drawer tests are performed with the patient in the supine position. The patient’s arm is brought overhead while the examiner stands at the head of the patient. By maximally flexing and externally rotating the shoulder, the humerus is “locked” into a fixed position. For the pivot shift test , the forearm is held in maximal supination while a valgus moment and axial compression is applied through the elbow at 40 to 70 degrees of flexion. In the relaxed patient with PLRI, this maneuver will lead to dimpling of the skin overlying the radiocapitellar joint, which occurs when the ulna and radius rotate off of the distal humerus. The subluxated elbow is reduced with flexion, frequently causing a palpable and visible (and sometimes audible) clunk. The posterolateral rotatory drawer test is performed in the same position. A posteriorly directed force is applied onto the proximal radius while holding the forearm and elbow in the same position as for the apprehension test. Dimpling of the skin around the radiocapitellar joint at 40 to 70 degrees of flexion confirms PLRI. The amount of instability should decrease with greater elbow flexion.
In addition, in our practice, we routinely examine patients with suspected PLRI under image intensification. The clinical suspicion can in many cases be confirmed radiographically, aiding in establishing an appropriate treatment plan. In addition to the aforementioned rotatory tests, the extended elbow can be simply loaded in varus. Pathologic gapping at the radiocapitellar joint confirms instability laterally. This can be readily compared with the contralateral, unaffected side (see the following).
Patients with PLRI characteristically actively resist provocative maneuvers that stress the joint, which in and of itself can be interpreted as a “positive apprehension sign.” However, in the cooperative patient, a successful examination can be performed with careful manipulation. As one would expect, the most reliable examination is performed under anesthesia. The recommendation is to always perform these maneuvers as the first step in evaluation of a patient for surgical reconstruction. It is also advisable to include these examination maneuvers prior to elective surgery for lateral epicondylitis.
Diagnostic Imaging
Plain radiographs of the elbow are frequently negative in patients with PLRI. However, small avulsion fragments or ossification at the humeral origin of the LCL can frequently be visualized. If PLRI is suspected, a lateral stress or varus stress view of the elbow can be obtained in the office using image intensification. The elbow is maximally supinated and axially loaded. Instability is confirmed by widening of the ulnohumeral joint and posterior subluxation of the radial head ( Figure 23.1 ). Anteroposterior radiographs or fluoroscopy under varus load can often reveal pathologic gapping of the radiocapitellar joint (see Figure 23.1 ). As noted, imaging of the contralateral elbow is recommended to help confirm asymmetric gapping or displacement. Magnetic resonance imaging can aid in confirming the diagnosis. Signal changes are commonly seen at the epicondyle, revealing disruption of the lateral collateral and tendinous origins at the humeral epicondyle ( Figure 23.2 ).
Pertinent Anatomy
The LCL complex originates at the base of the lateral epicondyle and lateral aspect of the capitellum. The isometric origin of the LCL is located at the geometric center of the capitellum. In the reduced elbow, the isometric origin is located at the intersection of a distal projection of the anterior cortex of the humerus and the longitudinal axis of the radial head. Distally, the LCL blends with the annular ligament to form a broad common insertion onto the proximal ulna ( Figure 23.3 ). The posterior fibers, which extend over 2 cm along the supinator crest from the proximal border of the radial head distally, have been termed the “lateral ulnar collateral ligament.” The LCL complex is covered anteriorly by the supinator muscle, which originates off the lateral epicondyle, supinator crest, and annular ligament. Posteriorly, the anconeus muscle is in close proximity to the LCL complex as it originates off the lateral epicondyle and inserts onto the lateral aspect of the proximal ulna.
Both ligamentous and musculotendinous restraints provide stability to the elbow. The LCL complex, along with the anterior bundle of the MCL and the ulnohumeral joint, has been shown to act as a primary stabilizer of the elbow. Clinically, lateral elbow instability requires insufficiency of both ligamentous and musculotendinous stabilizers. The most common mechanism involves proximal attenuation or avulsion of these structures from their humeral original. Occasionally, the distal insertion of the LCL may become compromised either as an avulsion injury or as a fracture of the supinator crest.
The contribution of the LCL complex and overlying extensor tendon origins to lateral elbow joint stability have been well described in ex vivo studies. The LCL complex represents the primary lateral stabilizer of the elbow, maintaining the ulnohumeral and radiocapitellar joints in a reduced position when the elbow is axially loaded with the forearm in supination. The extensor muscles, along with their fascial bands and intermuscular septae, assume a role as secondary restraints. The extensor muscles serve to independently support the forearm unit from laterally rotating away from the humerus. In supination, these muscles provide a static and dynamic force supporting the lateral joint. The extensor carpi ulnaris is the most proximal of the extensor muscles and thus has the best mechanical advantage in supporting the proximal forearm. This muscle has a consistent fascial band on its undersurface, which originates at the inferior aspect of the lateral epicondyle and inserts onto the ulna approximately 5 cm distal to the radial head. The fascial band of the extensor carpi ulnaris becomes taut in supination and, along with the extensor tendon origins and septae, provides secondary resistance to lateral rotatory instability.
Disruption of the LCL complex occurs in most instances as a consequence of an acute elbow dislocation mechanism. Although more than one pattern exists, dislocations frequently occur as the elbow is loaded with a combination of axial compressive, external rotatory, and valgus forces, in which the body internally rotates with respect to the affected extremity. In this setting, disruption of elbow stabilizers proceeds in a circular path from lateral to medial. Less frequently, instability may result as a consequence of a varus-deforming force applied to the extended elbow. LCL insufficiency should be kept in mind as a differential diagnosis in patients with nonremitting lateral epicondylitis, with or without a history of previous local steroid injections. Patients with chronic cubitus varus deformity, a prior history of failed surgery for lateral epicondylitis, or prior surgery of the radial head may have underlying iatrogenic lateral elbow instability.
Indications
Primary repair of the LCL is required in the setting of fracture-dislocations of the elbow. The so-called terrible triad of the elbow indicates a fracture of the coronoid process and radial head with an associated injury to the LCL. In this setting, LCL repair is an integral part of the treatment algorithm. In chronic PLRI of the elbow, some authors have shown favorable outcomes with simple repair of the LCL complex, but reconstruction is typically required to restore lateral joint stability.
Contraindications
LCL repair or reconstruction requires an intact buttress at the proximal radius. In cases of radial head insufficiency, operative reduction and fixation of the radial head or prosthetic replacement should accompany the reconstruction. Patient compliance with postoperative rehabilitation plays a key role in achieving adequate outcomes. Patients who are unable or unwilling to follow rehabilitation guidelines should not undergo reconstruction, especially as an elective procedure.
Technique
Author’s Preferred Technique
In the setting of chronic PLRI of the elbow, reconstruction is typically performed with tendon graft augmentation. Allograft hamstring and ipsilateral palmaris longus tendon grafts are most commonly used. If autograft is chosen for reconstruction, patients should be examined for the presence of a palmaris longus tendon. Frequently, the palmaris autograft is found to be suboptimal (too small or too short) to use for reconstruction. Alternative autograft options include the contralateral palmaris, flexor carpi radialis, and gracilis tendons. We favor hamstring allografts when the palmaris is not of sufficient quality, and the gracilis seems to be most optimal in terms of diameter and length.
Surgical equipment required for ligament reconstruction includes standard retractors and elevators for the elbow, drill bits and drill sleeves for the bone tunnels (typically 3.2 mm and 4.5 mm in diameter), a cannulated 4.5-mm drill, and strong braided nonabsorbable suture material. Optional equipment includes a tendon stripper for autograft harvest, ligature passers and/or fine monofilament wire (e.g., 26-gauge) to aid graft passage through the bone tunnels, and a cortical button.
The procedure is commonly performed under regional anesthesia with a long-acting block. Examination under anesthesia is recommended to confirm the diagnosis of PLRI. An extended Kocher incision is used beginning along the supracondylar humeral ridge and passing distally over the lateral epicondyle toward the ulna. Deep dissection is continued along the lateral supracondylar ridge, beneath the epicondyle and distally between the anconeus and the extensor carpi ulnaris. The anconeus is reflected posteriorly with the triceps and the extensor carpi ulnaris is retracted anteriorly, revealing the deep collateral and annular ligament layer overlying the radial head. The capsule over the so-called soft spot of the elbow is maintained to provide a layer between the joint and the graft.
In preparation for the humeral tunnel, a separate arthrotomy at the midline of the radiocapitellar joint exposes the epicondyle and the radiocapitellar joint. To reach this, the extensor carpi ulnaris and part of the extensor digitorum tendons are carefully elevated tangentially from posterior to anterior off of the deep ligament layer to the midline of the radiocapitellar joint. A transverse arthrotomy allows for direct inspection of the joint to visualize the curvature of the capitellum and identify its geometric center where the isometric origin of the LCL will be located ( Figure 23.4 ). Additionally, localization of the radiocapitellar joint will allow accurate placement of the ulnar tunnels. Not uncommonly, one will visualize wear and flattening on the rim of the radial head due to chronic subluxation.
It is important to have a clear understanding of the insertion of the lateral collateral and annular ligament complex when fashioning the ulnar tunnels. An entry hole is made in the lateral cortex of the ulna at the proximal margin of the radial head and just several millimeters posterior to the joint using sequential drill bits. Typically, a 3.2-mm drill bit is used followed by a 4.5-mm drill bit. An exit hole is created approximately 2 cm distally along the supinator crest (see Figure 23.4 ). Theoretically, more distally placed tunnels provide a graft that better resists varus stress and more proximal tunnels provide greater resistance to joint subluxation in supination. Curets are used to create a path within the ulna between the drill holes.
For the humeral graft attachment, we favor a single tunnel. This is easiest to create with a cannulated drill because the angle is quite “flat.” A 0.062-inch guide pin is started for a 4.5-mm drill bit so that the posterior and distal periphery of the hole will be located at the isometric origin of the LCL (see Figure 23.4 ). It is important to avoid placing the tunnel posterior to the isometric point, as this will lead to laxity of the graft in extension where it is needed most. Once adequate placement of this pin into the posterior aspect of the lateral humeral column has been confirmed, the 4.5-mm cannulated drill is advanced from distal to proximal without penetrating the far cortex. The far cortex is perforated using a 3.2-mm drill. This will allow for ideal fixation using the cortical button.
The tendon graft is obtained either by harvesting an autograft or by thawing an allograft. The graft is prepared by placing a running, locking nonabsorbable suture on one end (typically, the distal tendon.) A double-armed suture attached to a Keith needle (#2 FiberLoop, Arthrex, Naples, FL) can be used to facilitate this. The suture ends are shuttled through the ulnar tunnel using a bent suture passer or fine monofilament wire. Care must be taken to clear the tunnel adequately to allow passage of the graft. Prior to securing the tendon in the humerus, the lateral capsulotomy that had been made at the midline of the radiocapitellar joint is repaired. In addition, we have found it useful to reattach the origin of the native collateral ligament and extensor tendon origins to reinforce the reconstruction. To this end, a stout nonabsorbable running, locking suture is placed starting at the tendon and ligament origin on the humerus, run distally into the common extensor tendon down toward the ulna, and run back to the entry point. These sutures are passed into the humeral tunnel prior to the graft with the help of a straight suture retriever or wire. A hemostat helps maintain these proximally.
The prepared end of the graft is placed into the humeral entry hole with the sutures exiting posteriorly. Although the original description of the technique suggested the use of a four-ply graft, most surgeons now use a “docking” technique popularized on the medial side of the elbow for ligament reconstruction in the throwing athlete (see Figure 23.4 ). The goal of this method is for both arms of the free graft to be “docked” within the humeral tunnel, with only the two sets of sutures exiting out of the posterior humerus. Once approximately 10 to 15 mm of the graft is within the humeral tunnel, the second arm of the graft is cut at the appropriate length that will allow it to end within the humerus. Care is taken not to cut the graft too short. The second end of the graft is prepared with a separate running, locking suture. Tails of this suture are passed out of the humeral tunnel. Traction on the two sets of graft sutures should allow the two-ply graft to become taut as it advances within the humerus. When using this technique with one humeral tunnel, the suture ends are threaded through the eyelets of an endobutton behind the lateral humeral column.
The forearm is flexed to approximately 45 to 60 degrees and fully pronated, reducing any residual posterolateral subluxation. The forearm is lifted off of the table to remove any varus stress. First, the two ends of the suture that have been placed in the native tissue are tied over the posterior humeral bone bridge or endobutton. The tendon graft is pulled taut, and the four suture strands are tied, completing the reconstruction. The arms of the free tendon graft spanning the elbow joint can be sutured to one another and to the underlying collateral and annular complex to reinforce and tension the reconstruction if necessary. The elbow can be taken through a range of motion once the graft is secured. One will now appreciate the function of the graft, which acts as a reinforcement to the radial collateral and annular ligament complex. It holds up the proximal ulna to the humeral trochlea and, in addition, provides a lateral restraint to the radial head, not allowing it to subluxate laterally from the capitellum in supination.
For closure, the split in the anconeus and extensor fascia is repaired, sealing the reconstruction, and the skin is sutured in layers (see Figure 23.4 ). A compressive dressing is applied, with a splint maintaining the elbow in at least 90 degrees of flexion and the forearm in neutral rotation or slight pronation.
Postoperative Management and Expectations
Motion may be started at 7 to 10 days after surgery. However, motion may be delayed for 2 to 3 weeks without significant morbidity, as stiffness is not typically a problem in this patient population. A progressive range-of-motion program is subsequently started, with interval splinting for protection and support. Initially, all motion is performed with the arm at the patient’s side, avoiding shoulder abduction. Supination is allowed only with the elbow maximally flexed, which helps lock the ulnohumeral joint, thereby protecting the lateral soft tissue structures. Patients gradually gain elbow extension over the first 6 to 8 weeks. At that time, the protective splint is weaned and full extension should be safely achieved. Isometric strengthening can begin at 8 to 10 weeks. More vigorous strengthening or loading of the elbow is not started until closer to 4 to 6 months after surgery. Unrestricted use of the extremity is delayed until at least 6 months postoperatively, to allow time for the graft to incorporate and mature.
Expected Outcomes
Several surgical techniques have been described for management of PLRI. Most recently, Daluiski and colleagues reported on primary repair of the LCL complex in patients undergoing surgery within 30 days of injury versus more than 30 days after dislocation; the results were similar. In their cohort of 34 patients, only 2 had recurrent instability; both had undergone operation in the early postoperative period. Lee and associates reported excellent or good results in 8 of 10 patients who underwent either tendon graft reconstruction (6 patients) or humeral reattachment (4 patients). All patients treated with graft reconstruction had an excellent result. Nestor and coworkers reported on 11 patients who underwent either advancement or reconstruction of the lateral elbow. Of the five patients who underwent reconstruction with a palmaris longus graft, three were graded as having an excellent result and two as having a fair result, based on a scale that evaluates stability, range of motion, and pain. Lin and colleagues reported on 14 patients who underwent ligament reconstruction using either a palmaris or gracilis autograft. Reconstruction was performed in 11 patients with only lateral instability and 3 with concomitant medial instability. Excellent and good results based on the scale of Nestor and associates was reported in patients with lateral instability only, whereas of the patients with associated medial instability 2 had a good result and 1 a fair result. Using a docking technique for reconstruction of eight purely ligamentous PLRIs, Jones and coworkers reported a mean Mayo Elbow Performance Score of 88 (range, 75 to 100) at a mean follow-up of 7 years. Complete resolution of instability was achieved in six patients, while two had occasional instability. In a previous article, the senior author reported the results of reconstruction on 16 patients with documented chronic PRLI using the technique described in this paper. Symptoms of instability resolved in all patients, with elbow range of motion returning to baseline at 3 months after surgery. Loss of range of motion consisted of 5 to 10 degrees of terminal extension in 7 patients, but it did not affect final elbow function.
In a recent systematic review of the literature, Anakwenze and colleagues analyzed eight studies that included a total of 130 patients who underwent LCL reconstruction for PLRI. Ninety-one percent of patients had good or excellent results. However, complications occurred in 11% of patients, with recurrent instability occurring in 8%.
Complications
Recurrent instability is the most frequent complication after LCL reconstruction. This is reported to occur in up to 25% of cases. Revision surgery poses special challenges because of bone loss from a prior attempted reconstruction. Baghdadi and associates assessed 11 patients who underwent revision surgery for PLRI over an 11-year period. Although instability was corrected in 8 patients, only 6 patients achieved good or excellent outcomes according to the Mayo Elbow Performance Score.
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