∗ To my wife, Elissa, and our children, Meredith, Alexis, and Zoe.
† To my wife, Sandra, and our children, Michael, Mia, and Peyton.
The Essex-Lopresti injury or longitudinal radioulnar dissociation (LRUD) results from a triad of injuries to the interosseous membrane (IOM) combined with injuries to the radial head and distal radioulnar joint (DRUJ). A patient’s optimum recovery from this unforgiving injury depends on a high index of suspicion, accurate diagnosis, and timely treatment. Despite the appropriate management of some LRUD injuries, however, failed outcomes arise, and patients often present with chronic injuries. The ultimate salvage option has classically been creation of a one-bone forearm. This chapter, in particular, presents the reconstruction of the interosseous ligament (IOL) using a bone–patellar ligament–bone (BLB) graft, which is a novel surgical option that stabilizes the forearm, increases function, and decreases pain to the forearm and wrist in patients with chronic LRUD.
The radial head behaves as the primary restraint to proximal migration of the radius and is responsible for transferring the majority of the load at the wrist. In fact, Palmer and Werner demonstrated that approximately 80% of force at the wrist is endured by the radius compared with 20% by the ulna. Load transferred to the capitellum by the radius, however, is not equal to the 80% seen at the wrist; rather, only 43% of force is transmitted through the radiocapitellar joint and 57% at the ulnohumeral articulation. This change in force transmission between the radius and ulna is chiefly attributed to the IOM and the DRUJ.
Hence, an intact IOM and DRUJ are the primary soft tissues responsible for load transference from the radius to the ulna. If these soft tissues are jeopardized, however, the radius and ulna behave independently, and load across the distal radius is equal to the proximal radius and the load transferred at the distal ulna is equal to the proximal ulna. In addition, when the radiocapitellar relationship is compromised, as in a proximal radius fracture or radial head resection, the IOM and DRUJ are responsible for transferring the entire radial load to the ulna ( Fig. 53-1 A–D). The IOL and DRUJ experience increased stress when the radiocapitellar relationship is disrupted. As a result, 1 to 3 mm of proximal migration may be exhibited years after a radial head resection, which is usually asymptomatic.
Aside from serving as the secondary restraints to proximal migration of the radius, the IOM and DRUJ also provide stiffness to the forearm. Hotchkiss and colleagues illustrated that when the radial head is removed, approximately 71% of longitudinal stiffness of the forearm is attributed to the IOL and 8% to the triangular fibrocartilage complex (TFCC). Injury to the IOM and DRUJ creates dissociation between the radius and ulna along the longitudinal plane of the forearm, thereby resulting in the Essex-Lopresti injury.
The IOM is the most critical of the secondary restraints. It consists of three main bands of tissue: the central band (CB), the proximal band (PB), and the accessory bands (AB) that span between the interosseous crests of the radius and ulna ( Fig. 53-2 ). This tissue histologically and mechanically resembles a ligament and is more appropriately termed the interosseous ligament complex (ILC). These bands have a high collagen content and little elastin, similar to other ligaments, particularly the patellar ligament.
The strongest and most important component of the ILC is the central band, which is also called the interosseous ligament . It originates on the radius at an average of 7.7 cm from the head of the radius, angles 21 degrees from the axis of the radius, and inserts on the ulna approximately 13.7 cm from the tip of the olecranon, which is approximately one third of the length of the ulna from the tip of the styloid ( Fig. 53-3 ). It is trapezoidal in shape and is an average of 40 mm long and 1 to 2 mm thick.
The proximal band and accessory bands are less substantial in size, and their role in forearm stability is relatively minor. The proximal band, also called the oblique ligament , is inconsistently present and courses perpendicular and proximal to the IOL. The accessory bands vary in number from 1 to 5 and course parallel and distal to the IOL (see Fig. 53-2 ).
RATIONALE FOR TREATMENT
The Essex-Lopresti injury is a continuum that begins with a radial head fracture from a violent axial load ( Fig. 53-4 ). With continued axial loading, the IOL tears and injury to the DRUJ and TFCC may transpire. Thus, all these structures must be considered during the evaluation and treatment of Essex-Lopresti injury ( Fig. 53-5 ).
In an acute injury, the basic tenets of treatment are to reestablish the radiocapitellar articulation, repair the TFCC, and immobilize the forearm, allowing the IOL to heal. An acute injury is usually recognized within 4 weeks. Unfortunately, patients often present as referrals for chronic injuries or with failed initial management after radial head excision, which is typically more than 1 month after injury.
Open reduction and internal fixation (ORIF) of the radial head fracture is performed through a standard Kocher incision when three or fewer fragments are present. After exposure, a push-pull test is performed. Bone grafting may be necessary to fill bone defects. When the radial head is unsalvageable, a radial head arthroplasty is performed with particular attention that the radius and ulna are level at the wrist and that overstuffing of the prosthesis is avoided. Yet arthroplasty may behave as a temporary internal splint, and the IOL may not heal and create excess force transmission to the capitellum. As a result, it is recommended that patients with LRUD be forewarned that arthritis and pain at the elbow may develop.
The prosthesis should lie even with the lateral edge of the coronoid process on an anteroposterior view of the elbow. In the acute injury, joint leveling at the wrist can commonly be accomplished with proper radial head open reduction and internal fixation or arthroplasty without an ulnar-shortening osteotomy. A radial head excision should never be performed alone with an Essex-Lopresti injury. Also, silicone implants are not recommended because of their inability to withstand forearm load, risk of synovitis, and high frequency of implant fracture.
The wrist is then examined for stability. In a true Essex-Lopresti injury, the DRUJ is unstable and warrants immobilization to allow the IOL to heal. Wrist arthroscopy is generally performed with an arthroscopic or open TFCC repair. We then immobilize the forearm with a cast or hardware—either two 0.062-inch Kirschner wires or two 3.5-mm fully threaded cortical screws placed proximal to the DRUJ with the arm in supination ( Fig. 53-6 A and B). These are removed after 8 weeks. The uncertainty that the ligament actually heals with enough integrity to maintain its original function emphasizes the necessity to reestablish the primary restraint to proximal migration of the radius with appropriate treatment of the radial head injury.
Suture repair of the IOL has been described for acute injuries. Tears of the IOL appear to occur in the midsubstance of the tendon; however, there are some reports of injury to the ulnar insertion. An MRI or ultrasound of the forearm is recommended to locate the site of injury if this procedure is going to be attempted. The IOL can be approached through a dorsal incision between extensor digitorum communis and extensor digiti minimi quinti. Midsubstance repair can be done with a 2-0 nonabsorbable braided polyethylene suture. Suture anchors or drill holes can be used to repair tears from the ulna. Another option we have used in the acute setting is a pronator teres transfer as described by Kuzma and colleagues.
The primary objectives in the treatment of chronic injuries are to reestablish the radiocapitellar articulation, level the radius and ulna at the wrist, and reconstruct the IOL. If radiocapitellar arthritis exists, then radial head resection or implant removal is warranted as long as the IOL is reconstructed. However, patients with chronic injuries often present after a radial head resection with an initially missed injury to the IOL. An ulnar-shortening osteotomy is performed to level the ulna but should not be performed without IOL reconstruction, since the radius will continue to migrate until it impinges on the capitellum. The details of reconstruction of the IOL are described in the text that follows.
Other procedures may be necessary for coexisting pathology. We have concomitantly performed radial head excision, removal of radial head prosthesis, wrist arthroscopy, DRUJ resection, Sauvé-Kapandji procedure, and carpal tunnel release in our series of 16 patients.
INDICATIONS FOR REPAIR
The ideal candidate for reconstruction of the IOL of the forearm using a BLB graft is the patient with a chronic Essex-Lopresti injury, a radial head resection, wrist pain from proximal migration of the radius documented by appropriate radiographs, and no arthritis at the DRUJ or capitellum. Occasionally, other pathology is evident, and concomitant procedures may be necessary.
Making the diagnosis of an Essex-Lopresti injury is essential. These patients have a history of a violent axial load that causes a radial head fracture. Thus, all radial head fractures should be examined for injuries to the IOL and DRUJ. They may also present with wrist and forearm pain, although these are not always present. A thorough examination of the upper extremity should be performed with examination of the opposite side for comparison. Range of motion, grip strength, and stability of the DRUJ should be noted. Patients typically have a dorsal prominence of the ulnar head and reproducible pain with pronation and power grip ( Fig. 53-7 ).