Arthroscopic Trapeziometacarpal Arthroplasty

Videos corresponding to this chapter are available on DVD and online.

INTRODUCTION AND RATIONALE FOR PROCEDURE

∗ I would like to dedicate this chapter to three men who greatly shaped my style and character: my father Cristobal, who taught me how to work hard but enjoy life; my swim coach, Mike Scarpato, who showed me the value of perseverance and to avoid the “riff-raff”; and my main mentor in hand surgery, Joseph Imbriglia, who taught me to concentrate on what matters: both in hand surgery and life.

Trapeziometacarpal (TM) joint arthritis is one of the most common pathologic conditions affecting the hand and wrist. Initial treatment is usually directed at managing symptoms by conservative means. However, nonsteroidal anti-inflammatory drugs (NSAIDs), splinting, and even corticosteroid injections are usually palliative at best. Persistently symptomatic patients have had to face relatively aggressive surgical options in deciding whether they wanted a surgical solution to their frustrating problem. It is no wonder that patients often continue to suffer with pain when the traditional option of a complete trapezial excision is presented to them. Larger joints, including the knee, shoulder, hip, elbow, and even wrist, have benefited from the minimally invasive option of arthroscopy for decades. Only in recent years has thumb basal joint arthroscopy even been recognized as a potential treatment option.

A variety of surgical treatment options exists for the treatment of basal joint osteoarthritis of the thumb, ranging from conservative open debridement to more aggressive procedures such as fusion or even joint replacement. However, the standard of care has generally been complete trapezial excision, with or without an associated soft tissue stabilization. Herein lies the problem—there are few salvage options once the critical base of the thumb has been ablated. This finality, together with the usual prolonged painful recovery seen after trapezial excisional arthroplasty, hastens us to find an alternate solution for this common affliction. Arthroscopy provides this option. With the possible exception of the young laborer or much older low-demand patient, arthroscopic evaluation and definitive management may be indicated for the majority of arthritic thumb basal joints recalcitrant to conservative treatment. Radiographic changes occasionally correlate with the true articular cartilage loss, but an arthroscopic classification proves to be decisive for selecting the appropriate management protocol for different stages of arthritis. This author has clearly outlined three well-defined arthroscopic stages of TM joint arthritis ( Table 41-1 ).

TABLE 41-1

Badia Arthroscopic Classification ofBasal Joint Arthritis

Stage	Arthroscopic Changes
1	Intact articular cartilage Disruption of the dorsoradial ligament and diffuse synovial hypertrophy Inconsistent attenuation of the AOL
2	Frank eburnation of the articular cartilage on the ulnar third of the base 1st metacarpal and central third of the distal surface of the trapezium Disruption of the dorsoradial ligament plus more intense synovial hypertrophy Constant attenuation of the AOL
3	Widespread, full-thickness cartilage loss with or without a peripheral rim on both articular surfaces Less severe synovitis Frayed volar ligaments with laxity

AOL, anterior oblique ligament.

INDICATIONS

The main indication for arthroscopic TM arthroplasty is basilar thumb pain that is unresponsive to conservative treatment. This typically includes a trial of splinting with a forearm or palmar-based thumb spica splint, NSAIDs, and activity modification. A cortisone injection in the TM joint may be used as a temporizing procedure. Although it is well known that the x-ray findings do not always correlate with clinical symptoms, they are nevertheless instrumental in determining which patients may be appropriate candidates for an arthroscopic resection.

Eaton and Littler described a radiographic staging classification of TM osteoarthritis. Stage I consists of normal articular surfaces without joint space narrowing or sclerosis. There is less than one third subluxation of the metacarpal base. Stage II reveals mild joint space narrowing, mild sclerosis, or osteophytes less than 2 mm in diameter. Instability is evident on stress views with more than one third subluxation. The scaphotrapeziotrapezoid (STT) joint is normal. In stage III, there is significant joint space narrowing, subchondral sclerosis, and peripheral osteophytes of more than 2 mm in diameter but a normal STT joint. In stage IV, there is pan-trapezial osteoarthritis with narrowing, sclerosis, and osteophytes involving both the TM and STT joints. Burton modified this classification by incorporating clinical findings. Stage I includes ligamentous laxity and pain with forceful and/or repetitive pinching. The joint is hypermobile, which can be seen on stress views, but x-rays are normal. In stage II, crepitus and instability can be demonstrated clinically, whereas x-rays reveal a loss of the joint space. Stages III and IV are similar to Eaton‘s classification. Patients in stage I and possibly early stage II are appropriate candidates for arthroscopic debridement and capsular shrinkage.

I have has proposed a more specific classification based on the arthroscopic changes. Stage I includes intact articular cartilage, stage II includes eburnation on the ulnar third of the metacarpal base and central trapezium, and stage III comprises widespread full-thickness cartilage loss on both surfaces. Based on intraoperative findings, I have recommended debridement for stage I, with thermal capsulorraphy in the presence of dorsal subluxation, extension/abduction osteotomy of the metacarpal base and thermal shrinkage for stage II, and an arthroscopic interposition arthroplasty for stage III. An open arthroplasty is recommended in the presence of associated severe STT joint osteoarthritis ( Fig. 41-1 ).

Few patients present with arthroscopic stage I TM osteoarthritis in which articular cartilage persists, thus allowing simple synovectomy and perhaps thermal shrinkage capsulorrhaphy ( Fig. 41-2 ). Stage II patients have usually had ample conservative treatment, and arthroscopy reveals a focal cartilage defect ( Fig. 41-3 ). Simple debridement does not suffice, since this articular deficit usually progresses owing to the inflammatory joint process as well as aberrant joint mechanics including subluxation. This focal defect warrants a combination of joint debridement as well as dorsoradial closing wedge osteotomy ( Fig. 41-4 ) to change articular contact points and alter vector pinch forces seen within the joint. Unfortunately, patients do not usually present at this limited stage, either because of referral patterns or most likely because of the simple fact that patients are not offered surgery until they have reached an advanced radiographic stage. Nevertheless, despite an advanced stage of arthrosis, arthroscopy can still present great benefit to the symptomatic patient. This is mainly due to its minimally invasive nature and the premise that trapezial sparing is a key component.

Arthroscopic stage III arthritis (Eaton stage II or stage III) is characterized by full-thickness cartilage loss on the majority of the trapezium and a portion of the metacarpal ( Fig. 41-5 ). This is an indication for some type of interposition arthroplasty, since the advanced stage of disease demands some type of joint rebuilding procedure. Simple debridement, or even modification of the joint via osteotomy, will not suffice. To prevent painful grinding, the joint must be burred down to allow for interposition of some material. A variety of interposition materials have been described including tendon allograft or autograft, Graftjacket (Wright Medical Technologies, Inc, Arlington, Tennessee), and most recently Artelon ([polyurethane urea] Small Bones Innovations, Inc, Morrisville, Pennsylvania).

The Artelon spacer, which has been devised to prevent articular impingement and to provide scaffolding for tissue ingrowths, has shown promising results in advanced stages of basal joint arthritis. The biomaterial used in the Artelon spacer is polycaprolactone-based polyurethane urea, which weighs around 0.3 g and degrades by hydrolysis in about 6 years’ time. It is a synthetic weave material and can be introduced into the joint arthroscopically or by open surgery, often depending on the grade of subluxation associated with the arthritis. Basal joint arthritis with minimal subluxation is best suited for arthroscopic Artelon interposition. However, on occasion, younger, active patients may present with advanced arthritic changes combined with a high degree of TM subluxation. This grossly lax joint may be best suited for an open Artelon placement because the T-shaped wings of the Artelon implant serve to additionally stabilize the TM joint. These wings can be fixed with screws, sutures, or bone anchors ( Fig. 41-6 ). However, the arthroscopic indication is superior in that the TM joint capsule is not violated. Therefore, joint stability is maintained by performing the interposition arthroplasty via arthroscopic means. This not only allows for a minimally invasive approach, which patients prefer and may soon demand, but the postoperative recovery is faster and generally less painful due to diminished swelling from the arthroscopic approach. Since the primary problem is painful bone-to-bone contact in the well-aligned but advanced arthritic scenario, the interposition of a material to prevent this process and allow for native tissue ingrowths is an attractive and logical concept. To allow for adherence of the weave implant, it is important to immobilize the joint for nearly 6 weeks based on basic science studies outlining the phases of implant incorporation. This makes it a less attractive option for older patients, who may need early full use of both hands. Given the fact that the trapezium is spared, however, it is an ideal indication for the younger patient with advanced arthritis who will benefit from a trapezial-sparing approach. These patients often prefer not to use tendon grafts, and since one cannot control exactly where the dead tissue is interposed, a synthetic material that can accurately line the joint is an inherently more attractive option. Once the patient is indicated for Artelon arthroscopic interposition arthroplasty, the procedure is easily performed on an outpatient basis.

CONTRAINDICATIONS

An arthroscopic procedure implies that the joint morphology permits introduction of the scope to evaluate the stage and determine further treatment. Grossly deformed joints, with either large extracapsular osteophytes or severe subluxation, are better approached by open means to address these issues.

Trapezial sparing also precludes that the STT joint is free of painful arthritis. Although STT changes are often seen radiographically, it is the symptomatic joint or advanced x-ray findings that warrant trapezial excision. It is common to see mild radiographic changes in the patient with advanced TM arthritis, which should not necessarily lead one to recommend complete trapezial excision on a routine basis ( Fig. 41-7 ).