Posterolateral Instability Reconstruction





Introduction


Posterolateral rotator instability (PLRI) of the elbow describes the subluxation of the proximal ulna and radial head in a posterolateral direction relative to the distal humerus. Insufficiency of the lateral collateral ligament (LCL) complex has been implicated in the pathogenesis, eventually leading to instability of the elbow. Studies have shown that in addition to the entire complex, which includes the lateral ulnar collateral ligament (LUCL), radial collateral ligament, accessory LCL, and annular ligament, secondary stabilization is provided by both the bony anatomy and the common extensor group. , In the lateral ligament–deficient elbow with symptomatic pain and instability, ligamentous reconstruction of the LUCL restores varus and posterolateral stability. In acute injuries, LCL repair is a reasonable treatment option. In the more common setting of chronic insufficiency, reconstruction of the LUCL is the mainstay of treatment and has demonstrated superior results compared with repair. ,


LUCL reconstruction has been shown to be effective in restoring stability, with subjective patient satisfaction reported in 86% of patients. However, the procedure may lead to several complications and sequelae such as stiffness, which may require contracture release or excision of heterotopic bone, cubital tunnel symptoms requiring nerve decompression, or infection and hematoma requiring irrigation and debridement. , The most common reported complication is recurrent instability, which may be prevented by avoiding pitfalls during the preoperative, intraoperative, and postoperative phases of treatment.


In a 2014 systematic review of seven studies that included 76 elbows, the overall rate of complications was 11%, with six cases of recurrent instability, one case of superficial infection, and one postoperative hematoma. However, only two patients in this study required reoperation. A more recent study of LUCL reconstruction in U.S. military service members that was not included in the prior systematic review, 17% of patients experienced a complication, with 13% requiring a reoperation. The complications were related to cubital tunnel symptoms, postoperative flexion contractures, and deep infection.


Overall, a few cases have been reported in the literature of lateral ulnar collateral ligament reconstruction with relatively low complication and reoperation rates; however, an understanding of the potential problems during the preoperative, intraoperative, and postoperative phases is pivotal in preventing complications from arising. This chapter will outline the key considerations when planning, performing, and guiding patients through recovery following LUCL reconstruction, and how to approach complications if and when they should arise.


Preoperative Issues


Patients with symptomatic recurrent posterolateral instability in the setting of a history of trauma, chronic attrition, or iatrogenic injury to the LCL complex may be indicated for surgical intervention with a LUCL reconstruction using a tendon graft. Careful patient selection is critical for positive surgical outcomes and to help avoid the aforementioned potential complications. The presentation of patients with PLRI is varied, and thus appropriately indicating patients for surgical management is challenging. Most patients present with subtle instability that may make the diagnosis elusive, thus a thorough history is critical. Either pain or an inability to perform resisted elbow extension with the forearm supinated is often described by patients, without an overt sense of instability. Passive forearm supination can also result in pain over the posterolateral aspect of the radiocapitellar joint with subtle evidence of instability. In particular, patients may have difficulty pushing up from a seated position or opening a heavy door. Patients may present with a history of mechanical symptoms, including clicking, catching, and locking, with or without associated lateral elbow pain. In these subtle presentations, a high index of suspicion for lateral ligament deficiency should exist. In contrast, patients with a history of a fracture-dislocation or significant trauma may likely present with severe pain and gross instability.


In patients where PLRI is suspected, a careful physical examination is imperative and may demonstrate a positive posterolateral drawer test, posterolateral pivot-shift test ( ), chair test, or push-up test. Some of these maneuvers may not be grossly positive in the more subtle presentations; instead, patients will be apprehensive. Active and passive elbow range of motion (ROM) need to be assessed as well because rare patients may present with both stiffness and PLRI. These patients present not only a diagnostic conundrum, but also a challenge in management; both pathologies need to be addressed.


Video 38.1 Lateral pivot shift test.


Preoperative imaging is necessary to assist in diagnosis and surgical planning, with the ultimate goal of decreasing complications. Specifically, routine static anteroposterior (AP) and lateral elbow radiographs may identify associated pathologies such as underlying varus malalignment of the distal humerus from a prior fracture, posttraumatic degenerative changes, prior radial head resections, or a deficient coronoid. These osseous injuries may often need to be addressed to avoid persistent instability following reconstruction. , Similarly, in the posttraumatic setting, the radial head may be fractured, and thus prosthetic reconstruction must be planned for to prevent continued instability postoperatively. , If static radiographs are unremarkable for any associated pathologies, ulnohumeral widening, or impaction of the capitellum, fluoroscopic examination under anesthesia or local anesthetic can be useful in the diagnosis of PLRI. Patients may often be referred with advanced imaging, such as magnetic resonance imaging (MRI) of the elbow. Although a negative MRI does not rule out a diagnosis of PLRI, it may be useful in identifying other associated soft tissue pathology of the common extensor group and medial ligamentous structures, or to confirm the diagnosis of PLRI by demonstrating attenuation or disruption of the LUCL. ,


Once a decision is made to proceed with surgical management, several relative contraindications should be reviewed to avoid a suboptimal result. Young patients with open physes are at risk of growth arrest on the lateral side of the elbow, potentially resulting in a valgus deformity and delayed failure. Some patients with atraumatic PLRI may also have generalized laxity, and reconstructive efforts may only provide temporary stability. Patients should thus be evaluated in clinic with the Beighton criteria ( Table 38.1 ). If patients present with cubitus varus resulting from a deformity of the distal humerus, it is imperative to plan for a valgus-producing osteotomy, particularly when the deformity exceeds 20 degrees, owing to the fact that the deformity is the primary cause of the ligament deficiency which leads to the perceived instability. ,



Table 38.1

Beighton Criteria for Generalized Ligamentous Laxity




























Unable to Perform Able to Perform
Passive apposition of thumb to volar forearm 0 1 per side
Elbow hyperextension ≥10 degrees 0 1 per side
Knee hyperextension ≥10 degrees 0 1 per side
Dorsiflexion of small finger at metacarpophalangeal joint ≥90 degrees 0 1 per side
Palms flat on floor with trunk forward flexion & knees fully extended 0 1

Maximum score is 9. A score ≥5 is concerning for hyperlaxity.


Other associated pathologies need to be considered before surgical reconstruction of the LUCL for PLRI. Osteoarthritis has been considered to be a relative contraindication to ligament reconstruction as a result of potential continued pain postoperatively despite stabilization of the elbow. However, Kastenskov et al. demonstrated no difference in Mayo elbow performance scores following LUCL reconstruction in patients with or without osteoarthritis. One patient required an osteophyte removal several years following ligament reconstruction. Preoperative ulnar nerve symptoms should also be clearly evaluated to effectively counsel patients regarding the concomitant diagnosis, perform ulnar nerve decompression with or without anterior transposition, guide postoperative management, and anticipate possible joint contracture caused by the neurogenic injury.


Thus in the preoperative setting, complications associated with PLRI reconstruction can be avoided by making a correct diagnosis, recognizing associated problems that may need to be addressed at the time of ligament reconstruction or may affect the surgical outcome, and recognizing conditions that portend a worse outcome in the setting of instability. These can all be avoided by careful attention to the history, physical examination, and review of all available imaging.


Intraoperative Issues


Several techniques have been described for LUCL reconstruction; however, the general premise is that a graft is secured between the crista supinatorius and the lateral epicondyle. , , , , , , , , , , Graft options include palmaris longus and partial triceps tendon autograft, or various allograft options with similar outcomes. , , , , Our preferred technique is similar to that described by Camp et al.


At each part of the procedure, meticulous surgical technique can help prevent complications. The first intraoperative consideration relates to patient positioning. The authors’ preference is to perform surgery in the supine position. To visualize the lateral side of elbow in the surgical field, the glenohumeral joint is internally rotated with a resultant varus force on the elbow. This must be neutralized during graft fixation, which will be discussed later in this section. If an arthroscopy is planned before reconstruction, this may be performed with the assistant holding the arm stable or by positioning the patient in the lateral decubitus position with the arm secured in an arm holder. Although the lateral position may facilitate an easier arthroscopy, the arm holder makes the examination under anesthesia (EUA) extremely challenging. Thus prepping the entire arm free on a hand table in the supine position allows both full ROM and fluoroscopic visualization during EUA.


During the surgical exposure, it is crucial to clearly identify the layer of the lateral capsule and incise it sharply in line with the LUCL so that it may be repaired at the end of the procedure to place the graft reconstruction in an extraarticular position. Aggressive dissection may prevent later repair of the capsular flaps and also potentially devascularize the underlying bone, resulting in avascular necrosis.


Meticulous bone preparation is essential to avoid persistent instability postoperatively because several complications may occur at this stage, including tunnel malposition, bone fracture, and potential graft rupture. Bone preparation begins on the proximal ulna with two converging tunnels placed along the tubercle of the crista supinatorius. The bone tunnels should be oriented perpendicular to the long axis of the native LUCL and can be created with a high-speed bur or a drill allowing for an adequate bone bridge of at least 1 cm wide to prevent fracture ( Fig. 38.1 ). The two tunnels are connected and enlarged with the use of a towel clip, angled curettes, or a Bankart awl, which should be performed with care to avoid fracture of the bony bridge and, ultimately, graft failure. If a fracture does occur during surgery, several viable salvage options exist. One option would be to establish a new bone bridge by creating a new bone tunnel and connecting it to one of the prior holes; however, this is challenging owing to the limited bone available. Another option would be to use bone anchors for fixation, as described by Olsen and Søjbjerg. Lastly, an additional viable option would be to convert to a single-strand reconstruction, which has been shown in a biomechanical study to have no statistically significant difference in regard to stability when compared with a double-strand reconstruction. Nonetheless, patients should be protected postoperatively given the cortical defect and risk for catastrophic failure through the stress riser.


Jan 1, 2021 | Posted by in ORTHOPEDIC | Comments Off on Posterolateral Instability Reconstruction
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