Keywords
EPL rupture - Mini TightRope - suspensionplasty - trapeziectomy
Symptomatic degenerative joint disease of the first carpometacarpal (CMC) joint has
been successfully managed with various surgical treatments including trapeziectomy
alone, trapeziectomy and ligament reconstruction with or without tendon interposition,
metacarpal osteotomy, CMC arthrodesis, and CMC prosthetic arthroplasty; currently,
no single approach has shown superiority.[1]
Trapeziectomy and suspensionplasty with a commercially available Mini TightRope system
(Arthrex, Naples, FL) has been recently reported as an option to treat CMC degenerative
joint disease. This system utilizes FiberWire suture secured by two stainless steel
buttons in the first and second metacarpals to recreate the stabilizing force of the
anterior oblique ligament and prevent first metacarpal subsidence after trapeziectomy.
Cox et al and Yao and Lashgari have detailed this technique.[2]
[3] After using guidewire placement to establish entry and exit sites in the bases of
the first and second metacarpals, the Mini TightRope apparatus is inserted with accompanying
suture buttons and the apparatus is tensioned. Early active range-of-motion (ROM)
exercises have been recommended with protection of a thumb orthosis for up to 10 weeks.
Reported benefits include decreased donor-site morbidity associated with tendon harvest
and transfer, lack of need for K-wire fixation, prevention of metacarpal subsidence
with immediate postoperative stability, reduced operative time, and reduced postoperative
immobilization and recovery time.[3]
[4] Although initial reported outcomes have appeared promising, long-term data on complications
and safety are lacking. One case report previously reported an index metacarpal fracture
after TightRope suspensionplasty,[5] and another series reported two cases of a symptomatically prominent second metacarpal
button and one case of postoperative infection.[4] We report a complication of extensor pollicis longus (EPL) rupture after trapeziectomy
and suspensionplasty using Mini TightRope suture button fixation.
Case Report
A 71-year-old right-hand-dominant female underwent right CMC trapeziectomy with Mini
TightRope suspensionplasty at another center. She was immobilized in a thumb spica
splint, and motion was started 2 weeks postoperatively. On her second therapy session,
she noted acute-onset loss of thumb extension.
The patient moved to a new state and presented to our clinic at 3 weeks postoperatively.
Examination revealed superficial wound dehiscence of 5 mm over the first metacarpal
incision with underlying granulation tissue. There was no drainage or erythema. The
patient was unable to extend the thumb interphalangeal (IP) joint. Radiographs revealed
no fracture ([Fig. 1]). Magnetic resonance imaging (MRI) demonstrated no abscess ([Fig. 2]). We offered the patient an extensor indicis proprius (EIP) to EPL transfer.
Fig. 1 Posteroanterior (A) and lateral radiographs (B) of the right wrist demonstrating a patient status post trapeziectomy with tightrope
suspensionplasty and suture buttons in appropriate position.
Fig. 2 Axial T2 images of the right wrist at the level of Lister's tubercle with an intact
EPL tendon (A) and just distal to this point (B) revealing surrounding fluid and absence of tendon in Lister's tubercle (denoted
by *). At the level of the first metacarpal midshaft (C) the EPL can be clearly seen again. Coronal STIR image (D) revealing stump of ruptured EPL tendon at metacarpal base just distal to the Mini
TightRope stainless steel button.
A standard EIP to EPL tendon transfer was performed before exploring the previous
first metacarpal incision to prevent contamination of a potentially infected wound.
A ruptured EPL tendon slip was visualized with some surrounding pseudotendon at the
level of the suture button ([Fig. 3]). After EIP tendon transfer and wound closure, the prior incision over the first
metacarpal was then explored, revealing local capsular and dermal attenuation over
the suture button but no purulence. The implant was well fixed. This prior metacarpal
wound was irrigated and closed. Intraoperative cultures and Gram stain were negative
for infection.
Fig. 3 Intraoperative photographs of the right hand revealing EPL rupture.
At 3 months postoperatively, the patient had near-complete metacarpophalangeal and
IP joint extension ([Fig. 4]). At latest follow-up at 6 months postoperatively, the patient resumed normal use
of her thumb.
Fig. 4 Clinical photograph of the appearance of the affected right hand at 3 months postoperatively.
Discussion
We report a case of EPL rupture 3 weeks after a trapeziectomy and Mini TightRope suspensionplasty,
a previously unreported complication of this procedure. There are several possible
reasons to account for this complication. We feel that the most likely reason for
this complication was the prominent suture button causing dehiscence of the capsule
and skin, allowing for the EPL tendon to desiccate and rupture. This wound dehiscence
over the button may have allowed for degeneration of the tendon from exposure to air.
In vitro studies have shown that exposure of biologically intact tendons to air resulted
in decreased synthesis of matrix proteins, increased inflammation, and promoted fibrosis.[6]
[7] This patient had thin skin and little subcutaneous fat, and in this particular setting
a prominent subcutaneous implant may have allowed for wound breakdown close to the
surrounding extensor tendons. A comparison of abductor pollicis longus suspensionplasty
versus Mini TightRope suture button suspensionplasty by Avant and colleagues reported
a 7% rate of symptomatically palpable suture button implants over the second metacarpal
(2/27 cases), but no incidences of prominent implants in the first metacarpal.[4]
Another possible explanation could be tendon rupture from abrasion against the suture
button implant at the base of the first metacarpal, promoted by early ROM of the tendon
over the implant. EPL rupture has been documented in other situations of implant prominence,
most notably in distal radius fractures treated with volar locking plates in which
excessively long distal locking screws are prominent in proximity to Lister tubercle.[8] At the time of surgical exploration in the current case, the ruptured distal end
of the EPL tendon was in close proximity to the button, and this was also verified
on preoperative MRI imaging ([Fig. 2D]). Cox and colleagues recommended that the suture button be placed just ulnar to
the radial aspect of the abductor pollicis brevis muscle belly and away from the more
ulnar EPL tendon in the third compartment.[2] Improper seating of the suture button over the line of pull of the EPL tendon may
have resulted in direct abrasion of the tendon and eventual rupture. Preoperative
radiographs and intraoperative inspection, however, revealed that the button was slightly
radial to the line of pull of the native EPL tendon, making this explanation less
likely.
Lastly, a less likely possible explanation for EPL rupture is the initiation of an
acute inflammatory reaction to the suture material. FiberWire suture, which has a
unique ultra-high-molecular-weight polyethylene monofilament core, has been shown
to rarely incite soft tissue reaction, and case reports have shown soft tissue irritation
and granuloma formation mimicking infection and causing a severe soft tissue inflammatory
response.[9]
[10] Previous reports have hypothesized that small particle polyethylene suture debris
may promote macrophage activity and an associated inflammatory response, findings
which have been demonstrated on postoperative histological analysis.
This patient's EIP to EPL tendon transfer successfully restored thumb extension ([Fig. 4]). An additional benefit of the EIP transfer in this particular setting is that it
offers a slightly more ulnar vector of pull of the transferred EIP, thus potentially
placing the transferred tendon further from the site of the suture button on the dorsal
radial base of the first metacarpal.
The Arthrex Mini TightRope apparatus has been reported to offer advantages including
decreased operating time, less donor-site morbidity, decreased metacarpal subsidence,
and decreased immobilization and recovery times.[3]
[4] As its utilization increases in the treatment of CMC disease, complications such
as documented in this case report will need to be further studied.
