The metacarpophalangeal volar plate arthroplasty

Vol. 14A. No. 2. Part 2 March 1989

Arthroplasty of metacarpophalangeal joints

In Vainio’s method the metacarpal head is resected, the extensor tendon is sectioned proximal to the joint, and its distal end is interposed between the proximal phalanx and the resected metacarpal and sutured to the palmar plate (Fig. 5, A and B); the proximal extensor tendon stump is sutured to the distal extensor tendon over the base of the proximal phalanx. The long-term results are not reported. We feel that it is difficult to obtain any amount of flexion with this “square type” of resection arthroplasty because the two flat bony surfaces are abutting each other. Harrison’s’ method included resection of 2 cm of metacarpal head and neck, synovectomy, centralization of the extensor tendons with a distally based tendon slip made of half of the extensor digiti minimi passed through each tendon at the dorsal hood, and suture of the free end of the tendon slip to the extensor indicis proprius after it was transferred to the radial side of the base of the proximal phalanx (Fig. 6). Harrison reported on 32 cases of resection arthroplasty; one case was followed up for 3 years, 26 cases for more than 6 months. and six cases for less than 6 months. Thirty to 40 degrees of active motion and 60 to 70 degrees of passive motion were reported in 19 cases; motion was limited in seven cases. He reported that “radiological follow-up of 26 cases for not less than 6 months showed no definite erosive changes in the metacarpal after surgery, although molding of the bone ends and transient periostitis were present in most cases.” In 1961 SteindleP presented a brief description of arthroplasties of the MP joints at the annual meeting of the American Society for Surgery of the Hand. He stated that “it is necessary to remove the metacarpal heads and thereby overcome the irrestible extension contracture of these joints.”

There is general agreement that on long-term follow-up of rheumatoid cases, the bone of the metacarpal shaft gradually undergoes absorption and shortening after resection arthroplasty. Metacarpal shortening occurs with the Fowler tenodesis of the extensor tendon, the Tupper palmar plate interposition, the Vainio extensor interposition, or no interposition. The long-term follow-up of any type of resection arthroplasty eventually results in absorption and shortening of metacarpal bone. This is accompanied by progressive instability, recurrence of palmar subluxation and ulnar drift, and finger shortening (Fig. 7). The development of the Brannon prosthesis for the PIP joint, which was followed by the Flatt prosthesis for the MP and PIP joints, was spurred on by these bony changes and the slowly increasing instability. The Swanson and Niebauer types of silicone rubber implants were next on the scene and will not be discussed here. REFERENCES 1. Riordan DC, Fowler SB. Surgical treatment of rheumatoid deformities of the hand. .J Bone Joint Surg [Am] 1958;40:1431_ 2. Kuhns JG. Rehabilitation of the hand in rheumatoid arthritis. J Bone Joint Surg [Am] 1958;40: 1432. 3. Kestler OC. Surgical procedure for painful arthritic hand. Bull Hosp Jt Dis 1946;7: 114. 4. Vainio KJ. In: Milch, ed. Surgery of arthritis. London: Williams and Wilkins, 1964:144-S. 5. Harrison SH. Excision arthroplasty of the metacarpophalangeal joints. In: Tubiana R, ed. The rheumatoid hand. Groupe d’Etude de la Main, Monograph no. 1. Paris: L’ Expansion Scientifique FranCaise, 1966. 6. Steindler A. Arthritis deformities of wrist and fingers. J Bone Joint Surg [Am] 19.51;33:849-62.

The metacarpophalangeal volar plate arthroplasty Jack W. Tupper,

MD*

The most common metacarpophalangeal (MP) joint deformity in rheumatoid arthritis is ulnar drift and flexion subluxation of the proximal phalanges. A brief review of the anatomy and pathology of the MP joint is useful to understand the principles of volar plate arthroplasty. From the Department of Orthopaedic fornia, San Francisco. Calif.

Surgery,

University

of Cali-

Reprint requests: Jack W. Tupper, MD, 2938 Webster St., Oakland, CA 94609. *Clinical Professor of Orthopaedic San Francisco. Calif.

Surgery, University of California,

Anatomy The dynamic anatomy of the MP joint may be thought of in terms of bony structure, ligamentous checkreins, and external muscle control, both extrinsic and intrinsic. From a ligamentous standpoint, the joint is held together by the collateral ligaments on each side and the volar plate anteriorly. The structure of the collateral ligaments is important. There are two major portions, each of which has a very different function: (1) the straplike MP portion, which attaches from bone to bone, and (2) the fan-shaped metacarpoglenoid portion, which attaches from bone to volar plate. This is known as the accessory collateral ligament CFig. 1). THE JOURNAL

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Tupper

Collateral ligament

/

Deeptransverse

metacarpal ligament

Saginal

fibers \

‘Deep

transverse metacarpal ligament

\ Accessory collateral llgamenr

Fig. 1. MP joint, radial view. The collateral ligament attaches bone to bone. The volar ulnar pull of the extrinsic flexors is restrained by the flexor retinaculum (pulley), which is anchored to the volar plate. The volar plate is anchored to the metacarpal neck by the accessory collateral ligament. The distal volar plate is strongly anchored to the proximal phalanx. (Reprinted with permission from Tubiana R, ed. The hand. Philadelphia: WB Saunders, 1985:chap 60.)

The metacarpoglenoid portion of the ligament forms a sling

for the volar plate, which is strongly attached to the proximal phalanx distally, but has a membranous proximal attachment to the metacarpal. The volar plate is structurally continuous on either side with the adjacent intercapitular ligaments. At about the same point in which the glenoidal fan (accessory collateral ligament) inserts into the volar plate are also attached two other important structures: (1) the proximal flexor retinaculum, which controls the position of the long flexor tendons as they enter the finger, and (2) just outside this (more radial or more ulnar, depending on which side of the joint), the transverse fibers of the sagittal band, attaching dorsally to the extensor tendon. The sagittal band stabilizes the extensor tendon in the midline while allowing it to move to and fro, as on a “bucket handle” (Fig. 2). Normally both the long flexors and the common extensor converge from the fingers toward the base of the ring metacarpal so that the tendons approach the fingers from a slightly ulnar direction. The tendency for the fingers to normally pull in an ulnar direction is checked dorsally by the sagittal bands and volarly by the proximal flexor retinaculum (pulley). Both the interosseous muscles and the extrinsic tendons pass volar to the MP joint, causing a strong resultant of flexor forces at this point. The most important deforming force arises from the long flexors, but certainly the long flexors and the interosseous muscles account for most of it. Pathologic conditions The metacarpal attachment of the strap portion of the collateral ligament is loosened by synovial invasion, with a resultant loss of joint stability. The thinner, fan-shaped portion of the ligament (accessory collateral) suffers a similar fate,

Fig. 2. MP joint, radial view. The accessory collateral ligament is not shown. Notice the structural continuity of the volar plate with the deep transverse metacarpal ligament. The sagittal fibers of the extensor hood are outside the collateral ligament system, attaching to the zone between the volar plate and the deep transverse metacarpal ligament. The attachment is lateral to the volar attachment of the pulley. (Reprinted with permission from Tubiana R, ed. The hand. Philadelphia: WR Saunders, 1985:chap 60.)

compromising the metacarpal anchor of the volar plate. The normal pull of the flexor tendon is first on the proximal flexor retinaculum (pulley), which in turn pulls on the volar plate. The volar plate pulls on the accessory collateral ligament, which has lost its effective anchorage to the metacarpal; therefore the ultimate pull of the tendons is on the attachment of the volar plate to the base of the proximal phalanx, an attachment that the synovium does not conquer. The synovial invasion attacks the sagittal bands and loosens the extensor tendons restraint; these gradually dislocate ulnar to the joint and lose their extensor action to gain an increasing mechanical advantage as ulnar deviators. As the joint becomes more flexed, the extensor hood shifts distally, and the interosseous muscles can no longer provide stabilizing forces but can only act as flexors. The deformity is progressive, and as the soft tissues on the volar and ulnar aspects contract, it becomes irreducible. Surgical correction Surgery should accomplish the following: (1) remove the cause of joint disorganization-synovectomy; (2) restore static stability-tighten loose ligaments; and (3) correct the deforming forces-the long flexors and the interosseous muscles. Resection arthroplasty: Technique A transverse incision is made across the MP joints and carried down to the extensor tendons. The skin flaps are mobilized proximally to the metacarpal necks and distally enough to expose the interosseous tendons. The large veins in the intermetacarpal grooves should be preserved. The extensor tendons are mobilized from their ulnar position. The

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Metacarpophalangeal volar plate arthroplasty

Proximal

/ War

plate

\

phalanx

373

Metacarpal stump

Deep Wansverse metacarpal ligament

Fig. 3. MP joint, radial view. The radial collateral ligament is severed from the metacarpal neck and reflected distally. The osteotomy line is shown. (Reprinted with permission from Tubiana R, ed. The hand. Philadelphia: WB Saunders, 1985:chap 60.)

attachments of the contracted hypothenar muscles to the small finger, both bony and tendinous, are sectioned. The ulnar sagittal bands are tight and are released on each finger by a longitudinal incision to allow the t&dons to be pulled in a radial direction. A longitudinal incision is then made on each joint through the radial sagittal band, developing the two severed parts of the band volarly and dorsally for later identification and use in centralizing the extensor tendons. Dorsally, beneath the extensor hood and proximal to the joint line, lies a pouch of synovium, which is dissected distally to the joint margin, in which the joint is entered. The radial collateral ligament is exposed, and its attenuated proximal attachment on the metacarpal neck is severed (Fig. 3). The ulnar collateral ligament is then cut to allow full visualization of the joint. The synovectomy is completed, with care taken to remove the small masses lying between the collateral ligaments and the metacarpal neck and also the portion between the metacarpal head and the proximal volar plate. The volar plate can be easily identified at this point and is always intact. Because of contracture of para-articular soft parts, the joint cannot be reduced until the metacarpal head is resected. Enough bone is removed to obtain good alignment of the joint (Fig. 4). At this point, the joint is irrigated with saline solution to remove any remaining fragments of synovium. Up to this point, there are few differences between any of the various methods of resection arthroplasty; however, my technique varies from that developed by Vainio in the subsequent steps of the procedure. Vainio’s method. The metacarpal head is resected. The extensor tendon is cut proximal to the joint, and the distal end is sutured to the volar plate. This shortens the extensor tendon and provides an interposition substance, although it does not cover the metacarpal stump. The proximal end of the tendon is resutured to the extensor at the dorsal edge of the proximal phalanx. Because of the bone resection, Vainio allows relative lengthening of the interosseous muscles. Good results have been obtained with this method. I have three objections to this procedure: (1) A solid interposition substance is not constructed for an optimal pseud-

Radnal collateral lkgament

Fig. 4. MP joint, radial view. The metacarpal

osteotomy is completed. A U-shaped incision is made in the volar plate. Scissors are used to cut the flexor pulley attachments. The longitudinal lines show the incisions made outside the pulley attachments. (Reprinted with permission from Tubiana R, ed. The hand. Philadelphia: WB Saunders, 1985:chap 60.)

Saglttal

band

metacarpal

ligament

Fii. 5. MP joint, cross section. The knife shows the longitudinal line of incision in the volar plate outside the pulley attachment and inside the sag&al band attachment. Scissors enter from within the joint (dorsal) during the surgical procedure but are here shown in the volar aspect for diagrammatic clarity. (Reprinted with permission from Tubiana R, ed. The hand. Philadelphia: WB Saunders, 1985:chap 60.)

arthrosis. (2) Fixation of the extensor tendon to the base of the proximal phalanx does not allow the tendon to function well. There is no normal attachment at this site. (3) The strong forces from the long flexors are not checked, and much of the original deforming force is still transmitted through the same structures that previously gave way. ‘Ibpper’s method. The metacarpal head is resected. The volar plate is incised transversely at the junction of the fibrocartilaginous and membranous portions (Fig. 4). This junction can be easily identified with the tip of an instrument approximately at the level of the original metacarpal neck. The transverse incision brings into view the profundus tendon or the proliferative synovium surrounding it. The incision is

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Tupper

Volsr plate

I

Reflected -

proximal pulley

Metacarpal StUmD Fig. 8. MP joint, radial view. The volar plate is sutured to the metacarpal stump. The radial collateral ligament has been repaired. (Reprinted with permission from Tubiana R, ed. The hand. Philadelphia: WB Saunders, 1985:chap 60.)

Fig. 6. MP joint, volar view. This exposure is not made during operation. It is shown for anatomic clarity only. (Reprinted with permission from Tubiana R, ed. The hand. Philadelphia: WB Saunders, 1985:chap 60.)

Repaired radial sagittat fibers \

War plate

Fig. 9. MP joint, cross section. The radial sag&al bands have been shortened; the ulnar sag&al bands have been released. (Reprinted with permission from ‘Ibbiana R, ed. The hand. Philadelphia: WB Saunders, 1985:chap 60.) Fig. 7. MP joint, radial view. The metacarpal head has been excised. The volar plate has been reflecteddorsally and sutured to the metacarpal stump. (Reprinted with permission from Tubiana R, ed. The hand. Philadelphia:WB Saunders, 1985:chap60.)

extended laterally to just beyond the attachment of the flexor retinaculum. With blunt scissors, the flexor retinaculum is divided from the volar plate to a point near its phalangeal attachment. Just lateral to each of the retinacular attachments to the volar plate, distal longitudinal incisions are then made into the volar plate substance to expose the lumbrical muscle on the radial aspect (Figs. 4 to 6). The attachment of the sagittal band to the deep transverse metacarpal ligament (a transverse continuation of the volar plate) is preserved (Fig. 5). The proximal end of the volar plate is gradually reflected into the joint on its distal attachment (Fig. 7). The area of volar plate obtained will equal the cross-sectional area of the metacarpal stump. This method has three advantages: (1) It creates a thick, interposition substance, completely blocking any bone-to-bone contact; (2) it elevates the proximal phalanx;

and (3) it reestablishes the strong anchorage of the volar plate to the metacarpal, thereby stabilizing the flexor retinaculum and the proximal phalanx to prevent volar and ulnar forces of the extrinsic tendons from acting directly on the base of the proximal phalanx. Sesamoids should be removed if necessary. The extensor tendon does not need to be shortened and retains its norinal attachments. The bone resection of this procedure also relatively lengthens the interosseous muscles. Attachment of the volar plate to the metacarpal stump is sometimes facilitated by drilling small holes with a Kirschner wire. The next step is extremely important. The strap portion of the radial collateral ligament should be shortened and reattached to the metacarpal stump (Fig. 8). Its precise point of insertion should be on the dorsal radial aspect of the metacarpal stump. The best point can be identified by grasping the ligament with forceps to locate the precise area of insertion in which radial deviation and mild supination of the digit will be obtained. The ulnar collateral ligaments are ignored. When

Vol. 14A, No. 2, Part 2 March 1989

all of the radial collateral ligaments have been reattached, the fingers should be stable against gravity, without a tendency toward drift or pronation; if not, the attachment site is wrong or the ligament is too loose. The attachment of the radial collateral ligaments should be made with the joint in 45 degrees of flexion; otherwise an extension contracture may result. The balance of the extensor tendons must be reestablished. The stretched radial sagittal band is shortened by elliptical excision to checkrein the extensor tendon (Fig. 9). The two proprius tendons may be withdrawn above the extensor retinaculum and passed distally for reattachment to the radial

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side of the proximal phalanx if desired. It is unnecessary to transfer the ulnar intrinsic tendons to the radial side of the adjacent phalanges. A postoperative elevation sling is useful to control the swelling. Kirschner wire fixation of the joints is unnecessary after surgery. A volar plaster splint, with a gutter along the ulnar side of the small finger, is applied and should be used for 2 to 3 weeks. After removal of the plaster, a dynamic splint is used to allow radial stabilization of the fingers and at the same time help develop motion. This splint should be used at night for about 3 months.