Keywords

Introduction

Osteoarthritis of the hand and thumb is an exceedingly common symptomatic condition, particularly in the elderly patient. In patients older than age 75 years, thumb carpometacarpal (CMC) osteoarthritis has a radiographic prevalence of 25% in men and 40% in women [1]. It is especially prevalent in postmenopausal women. Armstrong and colleagues [2] studied the prevalence of thumb CMC arthritis in a consecutive series of 143 postmenopausal women. They found the radiological prevalences of isolated carpometacarpal and scaphotrapezial osteoarthritis were 25% and 2%, respectively. The prevalence of combined carpometacarpal and scaphotrapezial osteoarthritis was 8%; 28% of women with isolated carpometacarpal osteoarthritis and 55% with combined carpometacarpal and scaphotrapezial osteoarthritis complained of basal thumb pain.

Although the exact cause of osteoarthritis of the hand and thumb is not known, it is widely believed that mechanical stresses are to blame. The Framingham longitudinal study of radiographic hand osteoarthritis (OA) [3] examined the association between incident OA at different hand joints and maximal grip strength, which is a major determinant of forces at the proximal hand joints. Men with high maximal grip strength are at increased risk for the development of OA in the proximal interphalangeal and metacarpophalangeal (PIP), (MCP), and thumb base joints.

Reconstruction of the thumb CMC joint is among the most commonly performed hand surgery procedures. The impacts of thumb CMC arthritis on U.S. healthcare expenditures will likely increase as the number of people over 60 years of age doubles to approximately 112 million by 2050 [4]. A number of successful procedures have been employed for reconstruction of the arthritic thumb CMC joint.

Epidemiologic Findings

The prevalence of osteoarthritis of the thumb CMC joint is astounding, with the condition affecting up to approximately 1 in 4 women and 1 in 12 men [5]. Postmortem studies in Caucasians show a 50% rate of severe arthritis at the trapeziometacarpal joint. [6]. Female sex has consistently been shown to be a risk factor for the development of thumb CMC arthritis, with up to a six-fold increased incidence in women compared to men. This may be associated with an increased risk of ligamentous laxity [7]. The condition is a major cause of disability in the aging population. The prevalence of thumb CMC arthritis increases precipitously with age, with radiographic evidence rising from 9.0% in men aged 40–49 years to 31.5% in men aged ≥80 years, and 5.7% in women aged 40–49 years to 39.3% in women aged ≥80 years [8].

Numerous occupational risk factors have also been identified. Individuals in occupations believed to be at risk for thumb CMC arthritis (e.g., tailors, administrative assistants, domestic workers) have a four-fold increased risk of developing this condition. Patients whose occupations involve repetitive thumb use and heavy manual labor also have a 12-fold increased risk for thumb CMC arthritis [9]. Exposure to mechanical stress alone, however, is insufficient to fully explain the development of CMC arthritis. Other contributing factors are also involved, such as genetic and environmental factors, female gender, and comorbid predisposing influences.

Posttraumatic degeneration after intra-articular fractures may infrequently play a role in the development of thumb CMC arthritis, whereas traumatic or atraumatic ligamentous instability may hasten the process.

Anatomy and Biomechanics

The thumb is pronated and flexed approximately 80° relative to the plane of the palm at rest. This position permits opposition to the fingertips and more complex motions. The trapezium forms the base of the thumb mechanical axis [10].

The trapezium has a complex three-dimensional reciprocating saddle shape, imparting a high degree of motion and necessitating extensive secondary soft tissue stabilization [7]. The pantrapezial basal joint of the thumb is composed of five individual articulations: trapeziometacarpal (TM), trapeziotrapezoid, scaphotrapezial, scaphotrapezoidal, and trapezial-index metacarpal. The geometry of the TM joint is that of a bi-concavo-convex universal joint, both concave and convex on each side of the joint, meaning that there are two reciprocally interlocking saddle shapes that oppose each other. This unique geometry and partial constraint permits multiplanar motions, such as abduction, adduction, flexion, extension, hitchhiker, circumduction, and opposition, including screw-home torque rotation at the end phase of opposition [10]. The trapezial and metacarpal articular surfaces have different radii of curvature that become congruous only at the extremes of motion. The shallow concavity of each articular surface affords little intrinsic skeletal stability [11]. Therefore, the ligaments and muscles play varying and important roles in stability, laxity, and proprioception of this complex joint. The volar beak of the thumb metacarpal articulates with the recess in the volar trapezium, which is adjacent to the insertion of the anterior oblique “beak” ligament on the trapezium, locking into the trapezium recess pivot area during screw-home torque rotation. The complex interplay between bony and soft tissue stabilizers allows for screw-home torque rotation in the final phase of opposition, which provides the stability needed for power pinch and grasp (Fig. 54.1).

Fig. 54.1
figure 1

Trapeziometacarpal joint in its resting position. (Reprinted from Edmunds [32]. With permission from Elsevier)

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Because of the minimal bony stability of the thumb CMC joint and its lax and subluxatable nature in the resting position, it has numerous soft tissue stabilizers. As many as 16 ligaments have been identified, but six ligaments have been consistently found to confer joint stability [10, 12]. The deep anterior oblique “beak” ligament originates just ulnar to the volar styloid process at the base of the first metacarpal (beak) and inserts onto the volar central apex of the trapezium just ulnar to the ulnar edge of the trapezial ridge. Owing to its static nature and intra-articular location, the beak ligament serves as a pivot point for rotation, specifically for pronation, to produce opposition, and it becomes taut in wide abduction or extension [13].

Hand surgeons were traditionally taught that degeneration of this ligament primarily contributed to disease progression. Recent studies have disputed this assertion [11] and suggest that this is primarily a thin, capsular structure, with a mean thickness of just 0.71 mm and variable width. Histomorphometric staining to determine morphology and cellularity also support the notion that it is primarily a capsular structure consisting of disorganized connective tissue and lacking mechanoreceptors for mechanical feedback [12].

The dorsal ligament complex of the thumb CMC joint consists of the dorsoradial ligament and posterior oblique ligament. These are the largest, thickest and strongest ligaments of the TM joint, and are generally regarded as its most important soft tissue stabilizers. It originates from the dorsoradial tubercle of the trapezium and fans out to insert broadly onto the dorsal edge of the base of the first metacarpal. The dorsal ligament complex is the key force coupler that stabilizes the TM joint in power grip or pinch during the screw-home torque rotation final phase of opposition, which tightly compresses the volar beak of the thumb metacarpal into its recess area in the trapezium [12, 13]. The dorsoradial ligament becomes taut with a dorsal or dorsoradial subluxating force in all positions of the TM joint except full extension, and tightens in supination, regardless of joint position. It also tightens in pronation when the CMC joint is flexed [13].

Strauch et al. [14] conducted cadaveric serial sectioning of the thumb CMC ligaments with the metacarpal in neutral, flexion, and extension. The authors found that the primary restraint to dorsal dislocation was the dorsoradial ligament, with the anterior oblique ligament allowing dislocation by subperiosteal stripping from the base of the first metacarpal. While the volar ligaments are lacking in normal ligamentous structure and mechanoreceptor innervation, the dorsal ligamentous complex is composed of stout collagen in an organized fashion and has proprioceptive mechanoreceptors known as Ruffini endings present close to ligamentous attachments [15].

The ulnar ligamentous complex, consisting of the volar and dorsal trapeziometacarpal ligaments, forms a conjoined attachment—the ulnar collateral ligament—and provides a checkrein effect. The multitude of ligamentous structures surrounding the thumb CMC joint leads many to conclude that it is likely stabilized by the coordinated effects of all ligaments, and our understanding of the anatomy continues to evolve [16].

The complex movement and dynamic stabilization of the thumb CMC joint depends on the extrinsic, intrinsic, and thenar musculotendinous anatomy. The abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis, and flexor pollicis longus tendons provide the extrinsic support via their insertions onto the thumb metacarpal and phalanges. The intrinsic muscles affecting the thumb include the abductor pollicis brevis, adductor pollicis, flexor pollicis brevis, and opponens pollicis. There is a complex interplay between static and dynamic stabilizers during screw-home torque rotation. The intrinsic abductor pollicis brevis muscle abducts the thumb at the TM joint. The opponens pollicis then rotates the thumb, allowing flexor pollicis brevis, adductor pollicis longus, and flexor pollicis longus to further compress the TM joint. These coordinated motions allow the TM joint to gain articular congruence and rigid stability for power pinch and grasp during the final phase of opposition [11]. An additional intrinsic dynamic stabilizer has also been suggested [17]. In a radiographic analysis of 32 thumbs, activation of the first dorsal interosseous muscle appeared to reduce radial subluxation of the thumb CMC joint by an average of 4 mm.

Pathoanatomy and Altered Biomechanics

During the process of degeneration, the thumb metacarpal is pulled into adduction, with a compensatory metacarpophalangeal (MCP) hyperextension deformity. A series of studies provided compelling evidence to support the hypothesis that the degeneration of the deep anterior oblique ligament is the precursor to basal joint degenerative disease. In a cadaver study by Pellegrini et al. [18], postmortem material demonstrated eburnated lesions in the volar compartment of the TM joint in association with degenerative disruption of the adjacent deep anterior oblique ligament. The authors concluded that such a pattern would be expected in the setting of incompetent volar capsuloligamentous structures [19].

More recent studies have called these findings into question. In particular, analysis of normal anatomy has demonstrated that the volar ligaments are thin, disorganized capsular structures lacking in mechanoreceptors, which are responsible for joint proprioception [12]. In contrast, mechanoreceptors are abundant in the ligamentous attachments of the dorsal ligamentous complex, which are also stouter in structure. In addition, several cadaveric studies support the importance of the dorsoradial ligament in preventing dorsoradial displacement of the thumb metacarpal shaft relative to the trapezium [14, 20].

High compressive forces occur across the thumb CMC during pinch. They reach in excess of 12 times the applied load and may approach 20 times the applied load during maximum grasp. Cantilever bending occurs with these applied forces such that shear forces are created that are highest at the volar half of the joint’s articular surface. In an analysis of articular wear patterns [19], Pelligrini found that eburnation occurred only on TM surfaces in contact areas of the volar compartment. Furthermore, metacarpal degeneration began at the volar joint margin adjacent to the beak ligament and progressed dorsally, while trapezial degeneration originated on the central palmar slope and spread centrifugally with more advanced disease. Eburnation patterns were asymmetric, involving a greater surface area on the trapezium than on the metacarpal in a ratio of nearly 3–1. These observations suggest that progressive translation of the thumb metacarpal on the trapezium is responsible for the production of arthritic surface lesions, and support the hypothesis of pathologic joint instability as the cause of CMC arthritis. Although the arthritic pattern most frequently involves the TM joint, some patients present with concomitant scaphotrapeziotrapezoid (STT) arthritis. Whether the development of STT arthritis is regulated by an alternative mechanism or is the result of further progression is currently unknown [7].

Physical Examination

Patients with osteoarthritis of the thumb CMC joint present with either varied complaints of pain localized to that area, or more vague complaints of throbbing and/or burning in the radial aspect of the hand. A thorough physical examination of the joint begins with inspection. Patients with more advanced stages of joint degeneration will often present with a thumb adduction contracture and a compensatory thumb MCP joint hyperextension deformity and laxity.

After inspection, the CMC joint is palpated and evaluated using the grind test and joint subluxation test. The CMC grind test is performed with the examiner facing the patient. With the patient’s hand on a hand-examining table, the wrist is stabilized with one hand, and an axial load applied to the thumb axis with the examiner’s other hand. Pain, as well as crepitus, may be elicited as the degenerative articular surfaces are compressed and rotated. The CMC subluxation test is performed in a similar fashion, although the maneuver aims to gently force the CMC joint to subluxate and the examiner determines whether this elicits pain. Crepitus may also be apparent with this maneuver. Pinch strength testing, such as the two-point key pinch test or the three-point chuck pinch test using a dynamometer, may be assessed and compared to the contralateral side. Many patients with CMC arthritis will also present with ipsilateral carpal tunnel syndrome, with rates as high as 43% [21]. The examiner should ask about numbness in the distribution of the median nerve and nocturnal symptoms, and should inspect for thenar muscle atrophy. Diagnostic maneuvers, such as Durkan’s compression test, Phalen’s test, and median nerve percussion, may also be performed. EMG and nerve conduction studies may be considered if clinical suspicion is equivocal.

Imaging

Standard radiographs to profile the thumb CMC joint include PA, lateral, and oblique views of the hand or wrist. A true AP view of the thumb, or Robert’s view, and true lateral view of the thumb are also helpful. Robert’s view is obtained with the forearm in maximum pronation and a combination of positions, including shoulder flexion and internal rotation, so that the dorsal surface of the thumb can be placed directly on the radiograph cassette. A true lateral view of the thumb is obtained with the forearm flat on the table, the hand pronated approximately 20°, the thumb flat on the cassette, and the X-ray tube angled 10° from the vertical in distal to proximal projection. Advanced imaging studies such as MRI or CT scanning are rarely necessary for diagnosis or surgical decision-making.

Eaton and Littler [22] described four progressive radiographic stages of thumb CMC arthritis to guide management, which were later modified to include STT arthritis. This modified Eaton-Littler classification is now the most commonly used radiographic classification system for thumb CMC arthritis:

  • Stage I: Subtle carpometacarpal joint space widening

  • Stage II: Slight carpometacarpal joint space narrowing, sclerosis, and cystic changes with osteophytes or loose bodies <2 mm

  • Stage III: Advanced carpometacarpal joint space narrowing, sclerosis, and cystic changes with osteophytes or loose bodies >2 mm

  • Stage IV: Arthritic changes in the carpometacarpal joint as in Stage III with STT arthritis

Nonoperative Management

Many patients with thumb basal joint arthritis can be managed successfully with nonoperative management. The aim of conservative treatment is to restore thumb functionality, including pain relief, stability, motion, and strength. A recent systematic review [23] of randomized controlled trials (RCTs) found only a few high-quality studies addressing the conservative treatment of thumb CMC arthritis. Medications have a role in the treatment of thumb CMC arthritis. Traditionally, NSAIDs form the first line of medical treatment; however, there are no RCTs on the effects of analgesics, or superiority of one analgesic over another. Hand therapy was found to be beneficial in elderly patients with severe CMC arthritis. There is evidence that both steroid and hyaluronic acid (HA) intra-articular injections can reduce pain in patients with thumb CMC arthritis, although HA is not FDA approved for injection into the thumb. The effects of steroids are achieved faster, but are short-lived compared to HA, which seems to have a longer lasting effect after a slow start. Interestingly, in a study by Wolf and Delaronde [24], surveying active members of the American Society for Surgery of the Hand, 89% of surgeons favored the use of steroid injections for conservative management of thumb CMC arthritis.

Present evidence suggests that orthoses can give some pain reduction in patients with thumb CMC arthritis for up to 1 year, but do not influence hand function or strength. There is no strong evidence showing that a custom-made orthosis was superior to a prefabricated orthosis, that the length of one orthosis was superior to another, or that a patient should constantly wear the orthosis [23].

Because it is one of the most commonly seen hand surgery diagnoses, there is a pressing need for higher quality RCTs investigating the different conservative treatment modalities for thumb CMC arthritis. Ideally, future studies should include more patients, have longer follow-up times, and subgroup analyses regarding grade of OA; they should include pain scores, strength measurements, and patient-reported outcome measures [23].

Surgical Management

There are many types of surgery for thumb CMC arthritis, all having the same aim: to reduce pain and increase function. Root treatment for thumb CMC arthritis is most often trapeziectomy, either performed alone or in combination with various other modifications to achieve durable long-term outcomes. However, for early-stage arthritis (Eaton I and II), several joint-preserving surgical options are described. First metacarpal extension osteotomy, although not commonly performed, may benefit patients with mild-to-moderate thumb CMC arthritis [25]. A closing wedge osteotomy places the thumb metacarpal base in 30° of extension without the need for soft tissue reconstruction.

Arthroscopic treatment of thumb CMC arthritis is a relatively newer option and indicated for assessment of cartilage integrity, synovectomy, and loose body removal. Partial or total trapeziectomy performed arthroscopically is also possible [25]. A recent systematic review of arthroscopic debridement or partial trapeziectomy for thumb CMC arthritis suggested reduced pain and improved patient satisfaction similar to improvements documented in open studies, with durable results up to 7.6 years out [26].

Isolated soft tissue reconstruction was proposed by Eaton and Littler in 1973 [27]. The anterior oblique ligament reconstruction was achieved by routing a portion of the flexor carpi radialis through the base of the thumb metacarpal. They noted good or excellent long-term results in 95% of patients with no or minimal articular changes (Eaton I and II). By restoring stability, they were able to reduce pain and possibly even retard joint degeneration [28]. Some authors advocate isolated imbrication of the dorsoradial capsule for early arthritis and subluxation, which may improve stability [7].

Open trapeziectomy, first described by Gervis in 1949, has long been the surgical mainstay for more severe disease (Eaton III and IV). Later adjuncts included gelatin-sponge interposition, K-wire metacarpal support and soft tissue interposition that were added because of concerns about long-term subsidence; however, no statistical association between the amount of first metacarpal subsidence and follow-up key pinch, tip pinch, or grip strength was found [29]. One of the most widely used techniques today is the ligament reconstruction and tendon interposition (LRTI), which is the preferred method of 62% of active American Society for Surgery of the Hand members [24]. Through either a dorsal or volar radial incision, the joint capsule is incised and a trapeziectomy performed. An oval window is created on the dorsal surface of the first metacarpal, and its articular surface is removed. The flexor carpi radialis (FCR) tendon is harvested at its myotendinous junction and delivered into the wrist incision. Either part or all of the FCR tendon is then passed through the oval window in the first metacarpal and sutured to itself as a soft tissue interpositional autograft. Alternatively, the abductor pollicis longus (APL) or extensor carpi radialis longus may be used. If residual MP hyperextension remains, a volar capsulodesis or MCP arthrodesis may also be performed. Despite the popularity of the LRTI, there is only low-quality evidence supporting trapeziectomy with LRTI over trapeziectomy alone, with regard to pain, function, and adverse effects.

Aside from ligament reconstruction and interposition, there are other surgical options. Some authors prefer using a distraction hematoma arthroplasty by placing a K-wire from the first to the second metacarpal base, without a ligamentous interposition; this method has been shown to be effective in relieving pain and restoring function, despite evidence of late radiographic subsidence [30].

A simple reconstructive method for treating thumb CMC arthritis is the suture suspension arthroplasty (SSA) [31]. The SSA technique for thumb CMC arthritis reconstruction consists of trapeziectomy and a four-strand nonabsorbable suspension sling, creating a “hammock” between the distal-most insertions of the APL and the FCR. Pulling this construct tethers the base of the thumb toward the base of the index metacarpal, correcting the subluxation deformity and maintaining arthroplasty space. Additional options include the use of prostheses as spacers or trapezial replacements, although they have been only intermittently successful, and CMC arthrodesis.

Trapeziectomy and Suture Suspensionplasty Using the Internal Brace™

Exposure

Under light sedation, a nerve block of the median and terminal branches of the radial and lateral antebrachial cutaneous nerves is performed with 1% Lidocaine and 0.25% Marcaine. A 3- to 4-cm incision is made on the dorsal aspect of the CMC joint and trapezium, between the extensor pollicis longus and brevis tendons (Fig. 54.2).

Fig. 54.2
figure 2

A 3- to 4-cm dorsal skin incision over the dorsal aspect of the CMC joint

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The dissection is taken down to expose the abductor pollicis longus and the extensor pollicis brevis. After the tendons are exposed, a self-retaining retractor is placed between them. Next, the dissection is taken through the fatty tissue to expose the deep branch of the radial artery. The artery is mobilized dorsally and proximally and a longitudinal dorsal capsulotomy is performed.

Trapeziectomy

Subperiosteal dissection of the trapezium is taken ulnar, with the exposure of the trapeziotrapezoidal joint. The dissection is also taken radial and volar, to expose the entirety of the dorsal trapezium. It is critical to visualize the entire dorsal surface of the trapezium, including its articulations with the scaphoid, trapezoid, and first metacarpal. A freer elevator may be placed into the CMC joint to provide distraction and to aid in exposure of the dorsal surface of the trapezium and in its removal. A 9-mm McGlamry metatarsal elevator (Fig. 54.3) works extremely well for trapezium removal (at our institution, the McGlamry elevator is available in the podiatry trays). The advantage of the McGlamry elevator is its matching contour with the volar trapezial surface, allowing it to pass easily around its volar aspect and elevate the volar capsule.

Fig. 54.3
figure 3

The McGlamry metatarsal elevator

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It is best to remove the trapezium in three sequential steps:

  1. 1.

    Starting from the radial aspect of the trapezium, the McGlamry is passed around the volar aspect to elevate the volar capsule.

  2. 2.

    Next, the McGlamry is passed into the trapeziotrapezoidal joint to lever the trapezium out the radial side.

  3. 3.

    Finally, the McGlamry is passed into the CMC joint and the trapezium is levered out dorsally.

Internal Brace™ Placement

The articular surface of the first metacarpal base is exposed. This is easily achieved by inserting a small Hohmann retractor under its volar edge and flexing the first ray. The guide pin from the Arthrex 3.5 DX SwiveLock® SL anchor (Arthrex, Inc., Naples, FL) (Fig. 54.4) is drilled into the radial corner of the first metacarpal, midline between the volar and dorsal edges.

Fig. 54.4
figure 4

The Arthrex 3.5 DX SwiveLock® SL anchor (Arthrex, Inc., Naples, FL) Included in the kit are two 3.5 × 8.5 mm anchors with forked eyelets, 3.0-mm cannulated drill bit (for all-suture constructs), 3.5-mm cannulated drill bit (for graft constructs), 1.35-mm guide wires, tendon sizer, and fiberwire suture

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The wire is drilled until the black laser line is flush with bone (Fig. 54.5). The guidewire is overdrilled with a 3.0-mm cannulated drill. The drill guide has a depth stop at 1 cm.

Fig. 54.5
figure 5

The base of the first metacarpal is exposed with a small Hohmann retractor under its volar edge and flexing the first ray. The guide pin is drilled into the radial corner of the 1st metacarpal, midline between the volar and dorsal edges

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LabralTape™ (Arthrex, Inc., Naples, FL) is preloaded onto the forked eyelet of the first anchor. The preloaded anchor is then inserted into the drilled hole until the laser line is flush with bone (Fig. 54.6).

Fig. 54.6
figure 6

(a, b) The preloaded anchor is inserted into the drilled hole until the laser line is flush with bone

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The articular surface at the base of the second metacarpal is identified (Fig. 54.7).

Fig. 54.7
figure 7

The articular surface of the base of the second metacarpal is exposed

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The guide pin is inserted approximately 5 mm distal to the CMC joint and then overdrilled with the 3.0-mm cannulated drill (Fig. 54.8).

Fig. 54.8
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The guide pin is inserted into the base of the index metacarpal 5 mm distal to the CMC joint

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Both limbs of the LabralTape™ (Arthrex, Inc., Naples, FL) are preloaded onto the forked eyelet of the second anchor. The thumb is positioned in full adduction with just enough traction to visualize the hole in the second metacarpal (Fig. 54.9).

Fig. 54.9
figure 9

The thumb is positioned in full adduction with just enough traction to visualize the hole in the second metacarpal

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The second anchor is then seated until the laser line is flush with bone. It is important not to over or under distract the thumb when seating the second anchor. The excess LabralTape™ (Arthrex, Inc., Naples, FL) is trimmed with a scalpel (Fig. 54.10).

Fig. 54.10
figure 10

The second anchor is then seated until the laser line is flush with bone and excess labral tape trimmed

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Axial compression is placed on the thumb to test for any evidence of subsidence and maintenance of the arthroplasty space. The thumb is then brought through a gentle range of motion (Fig. 54.11).

Fig. 54.11
figure 11

(a, b) Axial compression is placed on the thumb to test for any evidence of subsidence and maintenance of the arthroplasty space

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The capsulotomy is closed with 3-0 vicryl sutures and skin with interrupted buried 5-0 monocryl. The patient is placed in a forearm-based thumb spica splint. At 1 week, the patient is transitioned to a custom molded forearm-based thumb spica splint, which may be removed to shower. At week 4, the patient begins occupational therapy with active range of motion and begins weaning off the splint. At week 6, the splint is discontinued fully and light strengthening is begun. The patient may resume full activity at 12 weeks postoperatively.

Surgical Tips and Tricks

It is critical to fully expose the entirety of the dorsal trapezium. The capsule is dissected off its radial and volar aspects. The dissection is continued ulnarly into the trapeziotrapezoidal joint. Next, the dissection is taken proximally into the scaphotrapezial joint and then distally into the CMC joint. This extensive dissection aids tremendously in excising the entire trapezium using the McGlamry elevator.

It is also important to tighten the Labral Tape™ as much as possible when inserting the second anchor. It is important to note that it is not possible to over-tighten this construct. Over-compressing the first and second intermetacarpal space, leading to loss of abduction and persistent pain, is possible with other techniques. With the Internal Brace™, when inserting the second anchor, the thumb is held in adduction and once the anchor is seated and thumb adduction released, the first metacarpal will naturally settle into a looser position.

Conclusion

From joint sparing techniques to simple trapeziectomy, LRTI and prosthetic arthroplasty, the treatment options for moderate-to-severe thumb CMC arthritis seem innumerable. We detailed a simple, efficient and reproducible technique for open trapeziectomy augmented with the Internal Brace™. This is an excellent option for pain relief, functional restoration, and prevention of long-term subsidence in patients with advanced thumb CMC arthritis.