The Role of Wrist Arthroscopy in Avascular Necrosis

INTRODUCTION

Although diagnostic arthroscopy of the wrist was first reported by Chen in 1979, it was not until 1986 that Roth and Poehling published a series of cases that served to define the role of arthroscopic surgery of the wrist. Wrist arthroscopy has rapidly evolved and now has a wide range of indications for the diagnosis, staging, and treatment of various wrist disorders, including avascular necrosis (AVN).

Of disorders of the carpal bones involving AVN, Kienböck’s disease (lunate AVN) and Preiser’s disease (scaphoid AVN) have received the most attention. The purpose of this chapter is to discuss the role of wrist arthroscopy as it relates to AVN of the carpus.

KIENBÖCK’S DISEASE

Historically, the radiologic classification of Kienböck’s disease described by Lichtman and associates has been used to assess the severity of the condition, although its reliability has been questioned ( Fig. 57-1 ). Other imaging modalities are also used to assess the disease ( Fig. 57-2 A and B). Arthroscopy provides additional direct visualization and assessment of the pathology in the radiocarpal and midcarpal joints. The disparity between radiographic assessment and arthroscopic assessment has been highlighted by Ribak and reinforced by Bain and Begg, who reported that it was not uncommon for plain radiographs to underscore the severity of articular involvement identified with arthroscopy.

Arthroscopy enables the surgeon to specifically identify the nonfunctional joints and tailor the surgical reconstructions to the anatomic findings.

Watanabe and associates were the first to report the arthroscopic assessment of Kienböck’s disease in 1995. The condition of the articular surfaces was assessed, in conjunction with assessment of the interosseous ligaments. Tears of the scapholunate and lunotriquetral ligaments were noted in all cases. They proposed diagnostic arthroscopy as a useful staging tool for assessment of intra-articular pathoanatomy in lunate AVN.

In 1999, Menth-Chiari and associates used wrist arthroscopy both for assessing the diseased joint and for debriding the necrotic lunate. They used arthroscopic debridement alone of the necrotic lunate in seven patients with Lichtman stage IIIA–IIIB. All patients reported significant improvement in pain relief and complete relief of mechanical symptoms at an average of 19 months’ follow-up. It was concluded that although progression of the disease cannot be altered, arthroscopic assessment and debridement may result in clinical benefit and defer more definitive surgery.

More recently (2006), Bain and Begg have used wrist arthroscopy to assess and classify Kienböck’s AVN of the lunate. This classification is based on the number of nonfunctional articular surfaces of the lunate and adjacent articulations ( Fig. 57-3 ). This differs from the previously established criteria of Lichtman, in which the staging classification is based on plain x-ray radiologic findings ( Table 57-1 ).

Indications/Contraindications

All patients with Kienböck’s disease who have been seen by the senior author are provided with wrist splints, offered nonsteroidal anti-inflammatory medications, and advised regarding modification of activities. Patients who continue to have pain despite these modalities are offered surgery after 6 months.

Based on the previously mentioned arthroscopic classification, the authors have proposed operative suggestions for treatments. In grade 0 Kienböck’s disease, all articular surfaces are normal; hence an extra-articular unloading procedure may be indicated. In grade 1, with one nonfunctional proximal lunate surface, a proximal row carpectomy (PRC), radioscapholunate fusion, or lunate excision and scaphocapitate (SC) fusion can be performed. In grade 2, the proximal and distal lunate surfaces are nonfunctional, which requires a proximal row carpectomy or scaphocapitate fusion (with lunate excision). Grades 3 and 4 require total wrist fusion or arthroplasty.

Technique

Wrist arthroscopy is undertaken using standard techniques. Multiple portals have now been described, and with the advent of new volar portals, it is now possible to have viewing and working portals that encircle the wrist. This enables the arthroscopic surgeon to view and instrument from all directions ( Fig. 57-4 ) The arthroscope and working portals can be adjusted to suit whatever diagnostic or therapeutic procedures are required, and in Kienböck’s disease, standard 3-4, 6R, and midcarpal portals are used.

A number of specific details are identified at the time of arthroscopy. These include the presence of synovitis and the appearance of the lunate articular surface. The articular surface is probed to see whether it has the normal hard intact subchondral bone or whether there is a floating articular surface due to a subchondral fracture. The other articular surfaces including the lunate facet of the radius and the articular surface of the capitate are also assessed.

Bain and Begg defined a normal articular surface as having a normal glistening appearance or only minor fibrillation, with a palpable hard subchondral bone. A nonfunctional articular surface was defined as having one of the following: extensive fibrillation, fissuring, localized or extensive articular loss, a floating articular surface, or fracture ( Fig. 57-5 A and B). The severity of any synovitis that is present is not used to specifically grade the disease; however, it is usually an indication of the severity of chondral changes. Bain and Begg observed that a characteristic pattern of change occurs in the lunate as the disease progresses. The changes always occur on the proximal convexity of the lunate, with many patients having a subchondral fracture. As the disease progresses, secondary changes occur within the lunate facet of the radius. However, it is unusual to have involvement of the lunate’s distal articular surface unless a coronal fracture has extended through to the surface or in severe late cases.