Introduction
Arthroscopy is gaining popularity as a procedure to treat intraarticular elbow pathology. The unique anatomy and size of the elbow joint make it a technically challenging joint to safely scope, with a higher potential risk of complications. Nelson et al. reported that, after 417 consecutive elbow arthroscopy procedures, they had an overall complication rate of 14%, with a major complication rate of 4.8% and a minor complication rate 8.9%. Although there was no significant difference in the rate of complication based on complexity of the procedure, they did find that rheumatoid arthritis (RA), prior elbow surgery, and a preoperative elbow contracture were risk factors for a complication. In another study, risk factors for a complication within the first 30 days after elbow arthroscopy were steroid use, higher American Society of Anesthesiologists class, renal disease, RA, and a preoperative diagnosis of trauma. Most of these risk factors do not play a role in the young, healthy population of children that receive arthroscopic treatment for their elbow osteochondritis dissecans (OCD) lesions; however, there are unique complications in this group that can either be prevented or at least diminished with awareness of the periarticular elbow anatomy, as well as meticulous technique.
OCD of the capitellum is a difficult condition to manage. It is defined as a progressive osteochondrosis localized to the capitellar subchondral bone and its associated vasculature. It is found in 2.1% to 3.4% of adolescent baseball players, , and most commonly in 10- to 21-year-old baseball players and gymnasts because of repetitive overhead throwing and upper extremity weight-bearing stresses across the radiocapitellar joint. Repetitive valgus compressive forces across the lateral column of the elbow result in localized injury of the subchondral bone of the capitellum, and occasionally the radial head. This results in a loss of structural support for overlying articular cartilage. , , , The athletes can present with pain, loss of motion, mechanical symptoms such as locking and catching, and decreased athletic performance. During clinical evaluation, it is necessary to differentiate a capitellar OCD from Panner disease, which is self-limiting osteochondrosis of the capitellum in children aged 4 to 12 years that rarely causes long-term sequelae. , Panner disease tends to involve most of the ossifying capitellum, and is not localized like OCD. If the child is between the Panner and OCD age groupings, and it is not clear on plain film the extent of involvement, then magnetic resonance (MR) imaging can help differentiate between the two by evaluating the extent of involvement or the presence of a sclerotic rim, which is pathognomonic for OCD.
Treatment of capitellar OCD lesions depends on the patient’s age, symptoms, classification of the lesion, and integrity of the overlying cartilage. , , Surgeons use a combination of history, clinical exam, x-rays, and MR with or without arthrogram to guide their decisions. However, recent studies illustrate the struggle in preoperatively predicting the size and stability of OCDs of the capitellum. , Byrd et al. demonstrated this difficulty by only accurately diagnosing three of ten baseball players’ elbow OCD lesions preoperatively. Lesions are usually classified as stable or unstable. Preoperatively, stable lesions are more likely to be seen in patients with open capitellar physes, who have radiolucency of subchondral bone only, and who demonstrate less than 20 degrees loss of motion. Stable lesions are more likely to heal with conservative management, especially in the younger population, and often do not require surgery unless they fail conservative management. Unstable lesions do not meet the discussed criteria, and surgical intervention is often recommended as the first line of treatment. , Arthroscopic classification is based on the International Cartilage Repair Society (ICRS) OCD classification system. Grade I defects are stable with continuous overlying cartilage, grade II defects have partial discontinuity but are stable with probing, grade III defects have complete discontinuity but are not displaced, and grade IV defects have a displaced fragment with a loose body or an empty defect ( Fig. 40.1 ).
The natural history of capitellar OCDs is unpredictable after skeletal maturity. Surgical intervention is indicated in cases of persistent symptoms after a course of conservative management, symptomatic loose bodies, defects to the overlying articular surface, and displaced or detached fragments. , , , , , However, there lacks a treatment algorithm because of the paucity of literature comparing the various surgical options and long-term outcomes. Both open and arthroscopic treatments have been described, but most authors suggest arthroscopy as an initial approach. Arthroscopic treatment options consist of removal of loose bodies, anterograde or retrograde drilling, abrasion chondroplasty, internal fixation of fragment, and/or osteochondral autograft implantation.
Intraoperative Complications
Positioning
Inappropriate positioning can cause neuropraxia, inadequate visualization, break in sterility, and prolonged operative time because of repositioning and difficulty of the case. , , Depending on surgeon preference and procedure requirements, the patient can be positioned supine, lateral, or prone (see Chapter 39 ).
The prone position is preferred by some surgeons because of easy access to both the anterior and posterior elbow via arthroscopy and the reduced risk of breaking sterility if a finger trap device is required, as used in the supine position. Complications from poor padding and positioning can lead to ventilation and neurovascular compromise to extremities. With the patient prone, the face must be well padded and the airway secured. Chest rolls help lift the chest and abdomen from the table and thus decrease the pressure needed to ventilate. The knees and feet should be well padded at their pressure points. The nonoperative arm can be placed over a well-padded arm board with special attention to the ulnar nerve, or tucked at the patient’s side. The operative arm is draped over a well-padded arm board along the side of the table. It is recommended to check pulses in all four extremities after positioning. Once sterile draping is completed, it is recommended to place a stack of rolled towels under the operative arm to allow the elbow to flex to 90 degrees and align the humerus in the coronal plane of the patient’s body. , , The greatest disadvantage to this position is converting to an open surgical approach should it be required.
A lateral decubitus position has several advantages and disadvantages when compared with the prone and supine positions. The lateral position is recommended over prone when there is concern for airway management because of extreme body habitus or compromised lung capacity. Plus, it is easier to convert to an open procedure, particularly if a posterior approach is indicated, because more shoulder mobility is attainable. Compared with supine positioning, lateral positioning provides equal access to the anterior and posterior compartments of the elbow, and the upper arm has a stable platform that prevents motion during the procedure. Conversely, the lateral position is problematic in very small patients, such as gymnasts, because of difficulty positioning the patient and maintaining access to the elbow. Similar complications related to airway and neuropraxia can occur with this positioning, particularly if awkward upper extremity positioning stresses the brachial plexus. In the lateral decubitus position, the patient is positioned on his or her side on an inflatable beanbag. An axillary roll is placed below the axilla, with the operative extremity placed in an arm holder or over a padded horizontal post. As described with the prone position, the same care is needed to protect and secure the face and airway, as well as pad the knees and elevate the feet. It is recommended to check pulses in all four extremities after positioning.
Supine position can be performed in either the cross-body or suspended position. Supine position, in general, has decreased positioning complications related to airway and posture-related neuropraxias compared with the lateral and prone positions. Nonetheless, pressure points should still be padded, airway secured, knees padded, and feet elevated. For the supine cross-body position, there are various commercially available arm holders. This position is safe and effective and provides easy conversion to an open procedure if an arthrotomy is required without breaking sterility or repositioning. However, the elbow is not rigidly secured against a post, which can make complex procedures more difficult. With the arm suspended in the supine position, the hand or wrist is hung from a traction device, (i.e., finger traps), and thus carry the same issues with elbow instability during the procedure. In addition, the supine suspended position poses the risk of the arthroscope withdrawing from the portal unexpectedly during trocar switching. Lastly, this position provides poor access to the posterior compartment of the elbow, given the a near vertical alignment, which makes arthroscopy difficult. , All things considered, being proficient in all three positions allows the surgeon the flexibility to adjust the surgical environment to best treat the lesion and patient.
Peripheral Nerve Injury
Peripheral nerve injury has a higher incidence in the elbow after arthroscopy than other joints because of the proximity of the neurovascular structures to the working field and portals ( Fig. 40.2 ). , , , Although some argue that the incidence is underreported, the prevalence is variable (0%–14%) , and ranges from transient sensory neuropraxia to complete transection. Desai et al. reported on 222 nerve injuries referred after elbow arthroscopy. In this survey, hand surgeons reported that almost half of these injuries required surgical intervention, including grafting, tendon or nerve transfer, or nerve repair. Of these interventions, 77% had only partial or no motor recovery. Nonetheless, the majority of nerve injuries reported in the literature are transient sensory neuropraxias, rather than complete paralysis. , The most commonly injured nerve is the ulnar nerve, followed by the superficial radial nerve, posterior interosseous nerve (PIN), anterior interosseous nerve, and medial antebrachial cutaneous nerve. , ,
Knowledge of the periarticular neuroanatomy of the elbow, its relationship to portal locations, and its deviations after saline insufflation and elbow positioning are keys to preventing nerve complications. The portals and bony and soft tissue landmarks should be marked with attention to the location of the ulnar nerve and if subluxation occurs in flexion. To some surgeons, prior subcutaneous nerve transposition is a relative contraindication to arthroscopy, whereas sub- or intramuscular transposition is an absolute contraindication to elbow arthroscopy. In the presence of previous ulnar nerve transposition, the surgeon should visualize the ulnar nerve before making the anteromedial portal. Before portal placement, the elbow should be flexed to 90 degrees and injected with 20 to 30 mL saline through the direct lateral soft spot. , Miller et al. demonstrated that elbow flexion and capsule distention increased the nerve-to-bone distance to an average of 1 mm for the ulnar nerve, 6 mm for the radial nerve, and 12 mm for the median nerve. However, the capsule-to-nerve distances were relatively unchanged with saline insufflation (ulnar nerve on the capsule, radial nerve and median nerve within 6 mm of the capsule). It was also demonstrated that elbow extension negates the protective effect of saline insufflation.
Nerve injury can occur unrelated to direct trauma to the nerve. Anesthesia can temporarily impact nerve function. Arthroscopy can be performed under either general or regional anesthesia. Although a regional block can be performed preoperatively, it is recommended that it be considered after completion of an intact nerve exam in the recovery room. These procedures are dependent on the comfort level of the anesthesiologist, and the use of ultrasound can reduce the morbidity associated with application. Other patient-related risk factors such as RA or presence of significant elbow contractures have a higher risk of having nerve injury after elbow arthroscopy. This is believed to be a traction injury from the increased range of motion (ROM) after contracture release. , ,
Inadequate Visualization and Access
Inadequate visualization and access to the entire capitellum will make the case more challenging and can lead to poor surgical technique and potentially iatrogenic complications, and thus poor patient outcomes. A standard five-portal technique is usually suitable for the surgeon to assess the entire capitellum and joint and provide an appropriate working field for the majority of treatments for capitellar OCD. The anteromedial portal provides good visualization of the capitellum, whereas the remaining portals are working portals and used for visualization of potential loose bodies (anterolateral, direct lateral, posterolateral, posterior central). Other accessory portals can be used to improve visualization. Loose bodies commonly are found in the olecranon fossa, posterior gutters, and anterior to the radioulnar joint. , , Flexion and extension of the elbow can also help with visualization of the capitellum.
Portal placement should start with skin incision only and then blunt dissection with the trocar through the capsule. The presence of fluid indicates intraarticular position if saline was insufflated intraarticularly at the start of the case. The anterolateral portal is commonly the first portal placed but has the smallest margin of safety because of its proximity to the PIN. To aid appropriate placement, this portal can be placed before saline insufflation to avoid alteration of palpable landmarks. The anterolateral portal is placed anterior to the radiocapitellar joint, but erring more proximal can reduce injury to the PIN, which lies distally. Next, the anteromedial portal should be placed 1 to 2 cm distal and 1 to 2 cm anterior to the medial epicondyle. Another technique that can be used to ensure suitable position is an inside-out technique that involves placing the camera in the anterolateral portal and traveling medially through the flexor-pronator mass to the desired anteromedial portal position. The surgeon can then incise at the location of the light and tented skin. The direct lateral portal is created at the soft spot at the center of a triangle created by the radial head, olecranon, and lateral epicondyle. The portal allows good access for treatment of the capitellum. The direct posterior portal is located 2 to 3 cm proximal to the proximal edge of the olecranon. A working space has to be created along the posterior humerus to remove the posterior fat pad for visualization of potential loose bodies in the joint. Be careful to keep the shaver turned away from the direction of the ulnar nerve. To further look for hidden loose bodies once the space is created, the posterolateral portal can be placed on the posterolateral surface of the olecranon at its proximal edge. , Avoid extensive dissection posteriorly because the capitellum is supplied by two end-nutrient arteries that enter posteriorly. , , A distal ulnar portal can also be useful for OCD lesions that extend to the posterior capitellum. The portal is created 3 to 4 cm distal to the radiocapitellar joint, and a blunt trocar is maneuvered proximally along the lateral border of the ulnar to the joint. In the end, the surgeon should never settle for incomplete visualization and access if he or she feels too limited with the arthroscope. The surgeon should be prepared for a lateral arthrotomy, if necessary. The Kocher approach to the lateral elbow between the anconeus and the extensor carpi ulnaris is most commonly used. ,
Technical Pearls and Pitfalls
Arthroscopic Loose Body Removal, Debridement, and/or Microfracture
A complete, thorough elbow examination is performed using the portals described earlier for full visualization of the extent of the lesion and loose bodies. The anteromedial and direct lateral portals provide visualization of the capitellum, whereas the anterolateral and direct lateral portals are good working portals. When assessing the lesion, take note of the size, stability, and viability of the fragment. If the defect is small and cannot be reattached and contained, it is recommended to be excised. , , On study found that small lesions less than 50% width of the capitellum had similar outcomes after fragment excision compared with reconstruction. Debridement is carried down beyond the zone of calcified cartilage and partial thickness of subchondral bone without extending into cancellous bone. It is important to debride to a clean vertical rim of healthy articular cartilage for the boundaries of the lesion. Microfracture is carried out through the anterolateral or direct lateral portals with an awl or Kirschner wire to puncture 4-mm depth defects every 3 to 4 mm within the lesion to stimulate a healing response within the lesion.
Arthroscopic Drilling
A complete, thorough elbow examination is performed as described previously. For ICRS stage I and II OCD lesions with intact overlying articular cartilage, arthroscopic drilling can be performed antegrade or retrograde to stimulate a healing response of the underlying subchondral bone. With the antegrade technique, the anterolateral or direct lateral portals are used to drill through the overlying cartilage and into the injured subchondral bone. It is important to redirect the drill in different directions with each perforation to get optimal access to the subchondral bone while doing the least damage to the overlying cartilage. Retrograde drilling requires an outside-in technique. A posterior cruciate ligament or anterior cruciate ligament guide can be used to drill a Kirschner wire from outside the elbow toward the lesion using fluoroscopic assistance and arthroscopic visualization ( Fig. 40.3 ). Multiple passes are recommended to enhance the healing response. ,
