Complications of Elbow Arthroscopy

Joint Congruence and Capacity

The elbow is one of the most congruous joints in the body; hence, the ability to manipulate the joint to separate the articular surfaces and allow better visualization is extremely limited, and multiple portals may be needed. Furthermore, the capacity of the joint is limited in the normal situation and is even further curtailed by most pathology. O'Driscoll et al. demonstrated an average normal capacity of approximately 30 mL. Posttraumatic and degenerative processes result in contracture of the joint, often allowing less than 10 mL of intraarticular distension. The soft tissue envelope of the elbow is extremely thin as compared to other joints, because in many locations it is separated from the outside environment by only a thin layer of subcutaneous tissue. Thus, the ability of the portals to “seal” is limited. This feature predisposes the elbow portals to chronic drainage and to the increased possibility of infection.

Neurovascular Structures

Without question, the greatest concern regarding elbow anatomy is the proximity of the radial and ulnar nerves that cross the joint in proximity to the capsule. The relationship of the radial, medial, and ulnar nerves to the capsule in both the distended and the nondistended positions has been studied extensively. ^a

a References .

Furthermore, the vulnerability of cutaneous nerves has also been studied in relation to the arthroscopic portal sites. These data are summarized in Table 23.1 . It is particularly important to note that distension of the joint does alter the relative location of cutaneous nerves as well as the radial and median nerves referable to the portal site. However, a distended joint in no way protects either of these nerves from an intraarticular procedure. As a matter of fact, the distended capsule may theoretically render these nerves more, rather than less, vulnerable. The most vulnerable nerve anatomically is the posterior interosseous nerve. A recent study presented at the 2016 Arthroscopy Association of North America meeting showed that the standard anterior lateral portal came in contact with the posterior interosseous nerve in five of nine specimens and recommended avoiding this portal entirely. Similarly, the median nerve demonstrates a variation of approximately 5 mm between the distended and the nondistended capsule referable to the anteromedial portal. However, once again, the distended capsule approximates the nerve—it does not separate the nerve. Although it is clearly the most protected, median nerve injury has been reported. Of great concern is a concurrent injury to the brachial artery or vein. Finally, the ulnar nerve actually rests on the posterior medial capsule. The greatest risk consists of procedures performed in the posteromedial corner of the elbow. However, injury from portal placement has also been reported.

In general, the motor nerves, and even cutaneous nerves, are not vulnerable to portal insertion if the portal sites are accurately defined and the joint is distended. Risk to cutaneous nerve is actually less than 10%, the most vulnerable being the medial cutaneous nerve. The risk of nerve injury is as follows: least risk, the median nerve; moderate risk, the ulnar nerve; greatest risk, the radial nerve.