The indications for elbow arthroscopy have expanded over the past several years. Currently, it is used for removal of loose bodies, treatment of lateral epicondylitis, synovectomy, contracture release, and management of osteochondritis dissecans1-4.
Although elbow arthroscopy is a relatively safe procedure, the reported complication rate is as high as 10%, which is higher than that seen with knee and shoulder arthroscopy3,5,6. The rate of neurovascular complications is reported to range from 0% to 14%5,6. In a review of a large series of patients treated with elbow arthroscopy, Kelly et al.5 reported a 2.5% rate of neurovascular complication, all of which were transient neurapraxias.
In the literature, there are only a few reports of complete nerve transection occurring during elbow arthroscopy7-10. In the present report, we describe a patient who presented, following an arthroscopic release of an elbow contracture, with a complete transection of a previously transposed ulnar nerve.
The patient was informed that data concerning the case would be submitted for publication, and he consented. Institutional review board approval was obtained.
A forty-five-year-old left-hand-dominant construction worker fell and sustained a small avulsion fracture of the coronoid process of the right ulna without an elbow dislocation. The elbow was immobilized in a posterior splint for four weeks. On removal of the splint, there was a restricted range of motion of the elbow. Intensive physical therapy was initiated with the aid of a turnbuckle-type splint to improve flexion. At four months after the injury, the active and passive ranges of motion were still limited (10° of extension to 70° of flexion, with full forearm rotation). The patient underwent an open release of the contracture and a subcutaneous ulnar nerve transposition with postoperative radiation to prevent heterotopic ossification. Four months postoperatively, he still had a limited range of motion (10° of extension to 65° of flexion, and unchanged forearm rotation); the neurovascular status was intact.
Four months following the open contracture release and ten months following the initial injury, the patient underwent arthroscopic release of the residual elbow contracture. The arthroscopic release was performed through proximal anteromedial and anterolateral portals. Postoperatively, he complained of numbness in the ring and small digits and weakness of finger abduction. Electrodiagnostic and nerve conduction velocity studies performed five months after the arthroscopic procedure confirmed severe ulnar neuropathy at or around the right elbow.
The patient continued to have a restricted range of motion of the elbow as well as hand numbness and weakness. Fifteen months following the original injury and five months following the arthroscopic release, he presented to our institution for a second opinion regarding the ulnar neuropathy and residual elbow contracture. On physical examination, he was found to still have a limited elbow range of motion (15° of active extension to 65° of active flexion) and full forearm rotation. He had intact motor and sensory function of the radial and median nerves but no sensation to light touch in the ulnar nerve distribution. The skin over the ulnar half of the ring and small fingers was dry and cracked. He had a positive Froment sign and weak dorsal interosseus muscles. He had weak finger abduction/adduction but a negative Pitres-Testut sign (the inability to radially and ulnarly deviate the long finger with the palm placed on a table). These findings seemed to imply either that some fibers of the ulnar nerve were intact or that a Martin-Gruber connection was present.
At this point, we elected to perform an open contracture release with ulnar nerve exploration and neurolysis and repair if necessary. Radiographs demonstrated no evidence of heterotopic ossification. No additional electrodiagnostic studies were performed.
On exploration, the ulnar nerve was found to have been transposed anteriorly. It was attached to the medial epicondyle by scar tissue, and a neuroma was present at the proximal stump (Fig. 1). The nerve was completely transected, with a 4.5-cm defect between the proximal and distal stumps (Fig. 2). This defect was just distal to the proximal anteromedial arthroscopy portal, but it could not be determined if the defect had been created during portal placement or during the arthroscopic capsular débridement. We performed an open contracture release, including a triceps tenolysis and a posterior capsular release, and subsequently placed a triple-cable autologous sural nerve graft (Fig. 3). Intraoperatively, the range of motion was markedly improved (0° of extension to 135° of flexion), and the arm could be taken through a full range of motion without placing any tension on the anteriorly transposed ulnar nerve and graft. Intensive physical therapy and continuous passive motion were started postoperatively.
The patient required a subsequent manipulation of the elbow at three weeks postoperatively. At his four-month follow-up visit, the active range of motion of the elbow was from 25° of extension to 105° of flexion. He had not regained appreciable sensory or motor function in the hand and had not yet returned to his previous employment at the time of writing.
Elbow arthroscopy is a technically demanding procedure because of the close proximity of the neurovascular structures to the capsule, the small capacity of the joint, and the complex geometry of the elbow. A variety of portals can be used, depending on the pathological condition being addressed, and the surgeon must understand the risks associated with each. Several investigators have examined the proximity of the portals to the neurovascular structures surrounding the elbow11-14.
A proximal anteromedial portal positioned proximal to the medial epicondyle and anterior to the intermuscular septum avoids injury to the ulnar nerve if the nerve is in its normal anatomic location11. Prior to the arthroscopy, our patient had undergone an ulnar nerve transposition, which placed the ulnar nerve directly in the path of the proximal anteromedial portal.
Distention of the articular capsule and elbow flexion both increase the distance between the portals and the normal anatomic location of the neurovascular structures. This displacement is substantially decreased when there is a joint capsule contracture. Gallay et al.15 showed that the capacity of an elbow joint with a capsular contracture averages 6 mL, which is 38% of the capacity that they measured in normal elbows. They also found that the compliance of the capsule of an arthrofibrotic elbow is reduced to 15% of normal values.
The majority of the elbow-arthroscopy-related transient and permanent nerve injuries reported in the literature have been associated with a posttraumatic capsular release. There have been reports of transient palsies of the median nerve16, the posterior interosseous nerve17, and the radial nerve from thermal injury18 during arthroscopic elbow-capsule releases of degenerative or posttraumatic contractures. Kelly et al.5 reported a variety of transient nerve palsies after contracture releases, but they attributed them to postoperative stretching or extravasation of local anesthetic. An extensive literature search identified only four reported cases of permanent nerve damage following elbow arthroscopy for treatment of a contracture. Permanent injuries to the median and radial nerves, the anterior interosseous nerve, the ulnar nerve, and the posterior interosseous nerve during the arthroscopic treatment of elbow contractures have been described7-10.
Open contracture releases have also been reported to be associated with nerve deficits. The most common problem associated with these procedures is ulnar neuritis developing during the postoperative course when an ulnar nerve transposition was not performed and the patient had <100° of flexion preoperatively19,20.
At the four-month follow-up evaluation after the open contracture release and nerve-grafting, our patient had an ulnar nerve deficit that was unchanged from the preoperative status. Roganovic and Pavlicevic21 reported the results of grafting for the treatment of thirty-nine ulnar nerve injuries around the elbow. On the basis of their data, our patient would be expected to have approximately an 80% chance of recovering some degree of superficial pain sensibility and tactile sensation. Their data also predict that he would have about a 40% chance of regaining sufficient motor function in the distal muscles to overcome gravity. However, as a result of the large time delay from the injury to the repair and the age of the patient, those percentages may be overly optimistic.
A surgeon must take into account several factors prior to performing an arthroscopic contracture release. These factors should be thoroughly considered during portal placement and capsular débridement. Posttraumatic elbow capsules have a decreased compliance that results in decreased displacement of the neurovascular structures with insufflation. It is imperative that the location of the ulnar nerve be identified prior to placement of medial-sided portals. This can be done by direct palpation, using ultrasonography22, or through open surgical exposure. It has been suggested that an arthroscopic procedure should not be attempted if there has been a previous operation on the lateral aspect of the elbow because of possible adherence of the radial nerve to the anterior aspect of the capsule22. Dodson et al.1 recommended avoiding an arthroscopic procedure if the patient has undergone a previous ulnar nerve transposition, as our patient did. Any congenital abnormality of the elbow should be a relative contraindication since it may place the neural structures in unexpected locations.
In conclusion, in order to decrease the risk of nerve injury, we recommend extreme caution when performing an arthroscopic release if the patient has previously undergone an open contracture release.