Content uploaded by Darshan Sunil Shah
Author content
All content in this area was uploaded by Darshan Sunil Shah on Jun 04, 2020
Content may be subject to copyright.
Available via license: CC BY 4.0
Content may be subject to copyright.
EDITOR’S CHOICE
The Effect of Surgical Treatments for
Trapeziometacarpal Osteoarthritis on
Wrist Biomechanics: A Cadaver Study
Darshan S. Shah, MS, PhD,*Claire Middleton, MBChB, MS,†Sabahat Gurdezi, MBBS, MS,†
Maxim D. Horwitz, MBChB,†Angela E. Kedgley, MS, PhD*
Purpose Studies have shown the effects of surgical treatments for trapeziometacarpal
osteoarthritis on thumb biomechanics; however, the biomechanical effects on the
wrist have not been reported. This study aimed to quantify alterations in wrist
muscle forces following trapeziectomy with or without ligament reconstruction and
replacement.
Methods A validated physiological wrist simulator replicated cyclic wrist motions in cadaveric
specimens by applying tensile loads to 6 muscles. Muscle forces required to move the intact wrist
were compared with those required after performing trapeziectomy, suture suspension arthro-
plasty, prosthetic replacement, and ligament reconstruction with tendon interposition (LRTI).
Results Trapeziectomy required higher abductor pollicis longus forces in flexion and higher
flexor carpi radialis forces coupled with lower extensor carpi ulnaris forces in radial deviation.
Of the 3 surgical reconstructions tested post-trapeziectomy, wrist muscle forces following
LRTI were closest to those observed in the intact case throughout the range of all simulated
motions.
Conclusions This study shows that wrist biomechanics were significantly altered following
trapeziectomy, and of the reconstructions tested, LRTI most closely resembled the intact
biomechanics in this cadaveric model.
Clinical relevance Trapeziectomy, as a standalone procedure in the treatment of trapeziometacarpal
osteoarthritis, may result in the formation of a potentially unfilled trapezial gap, leading to
higher wrist muscle forces. This biomechanical alteration could be associated with clinically
important outcomes, such as pain and/or joint instability. (J Hand Surg Am.
2020;45(5):389e398. Copyright Ó2020 by the American Society for Surgery of the Hand.
Published by Elsevier Inc. This is an open access article under the CC BY license (http://
creativecommons.org/licenses/by/4.0/).)
Key words Arthroplasty, LRTI, simulator, trapeziectomy, trapeziometacarpal osteoarthritis.
THE TRAPEZIOMETACARPAL JOINT is the most
common site requiring surgery for symp-
tomatic osteoarthritis in the upper limb.
1
Among the surgical methods proposed for the treat-
ment of severe basal thumb osteoarthritis—including
trapeziectomy with or without ligament reconstruc-
tion with tendon interposition (LRTI), implant
arthroplasty, arthrodesis, arthroscopic resection, and
metacarpal extension osteotomy—trapeziectomy, first
reported in 1949,
2
still remains a common component of
From the *Department of Bioengineering, Imperial College London; and the †Department of
Hand Surgery, Chelsea and Westminster Hospital, London, United Kingdom.
Received for publication September 1, 2018; accepted in revised form October 1, 2019.
No benefits in any form have been received or will be received related directly or
indirectly to the subject of this article.
Corresponding author: Angela E. Kedgley, MS. PhD, Department of Bioengineering,
Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom;
e-mail: akedgley@imperial.ac.uk.
0363-5023/20/4505-0002
https://doi.org/10.1016/j.jhsa.2019.10.003
Copyright Ó2020 by the American Society for Surgery of the Hand. Published by Elsevier Inc.
This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). r389
many modern surgical reconstructions.
3
However, the
trapezial gap, created by resection of the trapezium, can
cause persistent thumb weakness and instability, owing
to potential proximal migration of the thumb.
4
In addi-
tion, the pseudarthrosis of the firstmetacarpalwiththe
scaphoid can dislocate or degenerate, leading to pain.
5
Therefore, numerous surgical techniques have evolved
to prevent the proximal displacement of the first meta-
carpal post-trapeziectomy, such as temporary stabiliza-
tion with Kirschner wires (K-wires), prosthetic
replacements, and LRTI.
Some of the oldest surgical reconstructions include
the use of silicone elastomer implants.
6
Although
their designs attempt to preserve the natural anatomy
and biomechanics of the joint,
7
these implants have
been known to suffer from a few limitations, such as
implant loosening.
8
Wrist tendons, such as the flexor
carpi radialis (FCR), have been used as a graft to
create a tendon sling for the stabilization of the first
metacarpal
9
; however, tendon slings might not be
adequate to prevent proximal migration of the first
metacarpal if they yield under load.
4
To combine
features of a silicone implant and tendon slings, the
tendon tie-in implant has been proposed post-
trapeziectomy, wherein the tendon sling is wrapped
around the base of the implant, with the goal of
preventing dislocation.
10
The modern surgical technique of LRTI involves
the use of the FCR or other tendons for ligament
reconstruction, with varying knot designs for tendon
interposition.
4,11,12
Studies have shown that LRTI
using the FCR results in decreased pain and increased
grip strength and key pinch strength,
11
as well as
smaller proximal displacement of the first meta-
carpal.
13
Owing to the stability it provides without
the incorporation of an implant, LRTI is preferred
over other surgical reconstructions.
14
However,
studies have questioned the success of LRTI
15e17
and
have proposed a suture suspension arthroplasty pro-
cedure as a faster and less-invasive alternative to
harvesting a tendon graft.
18
Notwithstanding the growing popularity of LRTI
to treat trapeziometacarpal osteoarthritis, each of
the commonly performed surgical interventions
has associated advantages and limitations. Despite
the reported shortcomings of trapeziectomy,
4,5
in vivo studies based on the dimensions of the
trapezial gap, thumb pain, and thumb strength
13,19
question the need of surgical reconstructions post-
trapeziectomy.
20
In vitro studies comparing these
reconstructions by analyzing joint kinematics and
biomechanics are limited by the drawback of
applying passive or constant loads to the muscles
during the experimental protocol.
21,22
Therefore,
the primary objective of this study was to simulate
dynamic wrist motions on a physiological simulator
using active loads to compare a range of surgical
techniques and to quantify the effect of surgical
reconstructions commonly used to treat tra-
peziometacarpal osteoarthritis on wrist biome-
chanics by comparing wrist muscle forces for each
condition. We hypothesized that, owing to the
alteration of the trapezial gap, surgical intervention
would cause a rise in the muscle forces of the radial
flexors—FCR and abductor pollicis longus
(APL)—thereby altering the distribution of muscle
forces in the wrist from those observed in the
intact case.
METHODS
Specimen preparation
Nine fresh-frozen cadaveric specimens—7 women
and 2 men (mean age, 50.7 years; range, 31e59
years)—with no traumatic or musculoskeletal
degenerative pathology, were obtained from a
licensed human tissue facility. Ethical approval was
obtained from the institutional tissue management
committee according to the Human Tissue Act. The
specimens, stored at e20C prior to this study, were
thawed at room temperature for 12 hours. The 6 wrist
muscles considered for this study—FCR, flexor carpi
ulnaris (FCU), extensor carpi radialis longus
(ECRL), extensor carpi radialis brevis (ECRB),
extensor carpi ulnaris (ECU), and APL—were iden-
tified and dissected at their distal myotendinous
junction. All other soft tissue was resected 5 cm
proximal to the wrist, thereby preserving the wrist
capsule and the retinaculum. The elbow was fixed in
90flexion with neutral forearm rotation (pronation
angle, 0) using K-wires, while all digits were left
unconstrained.
Experimental setup
Specimens were mounted on a physiological wrist
simulator (Fig. 1).
23
Six linear actuators (SMS Ma-
chine Automation, Barnsley, UK) mounted in-line
with servo motors (Animatics Corp., Milpitas, CA)
were used to re-create wrist motions by applying
tensile loads to steel cables sutured to the tendons of
the 6 muscles. Tendon forces were measured using
load cells (Applied Measurements Ltd., Aldermaston,
UK) connected in series with the actuators. Clusters
of retroreflective passive markers fixed rigidly to the
390 EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS
J Hand Surg Am. rVol. 45, May 2020
third metacarpal and the radius were registered using
anatomical landmarks recommended by the Interna-
tional Society of Biomechanics
24
to define the coor-
dinate systems of the hand and the forearm,
respectively. Joint angles were obtained in real time
using an 8-camera optical motion capture system
(Qualisys, Göteborg, Sweden).
Active wrist motions were simulated in vitro by
means of hybrid control, which used position feed-
back to drive joint kinematics according to the input
set point waveform, with simultaneous force feed-
back to ensure muscle forces remained within phys-
iological bounds.
25
The control strategy minimized
kinematic error by computing the distribution of
actuator displacements across the 6 muscles to ach-
ieve the desired joint kinematics every 4 to 5 ms.
25
Specimen-specific moment arms of the muscles,
determined according to the tendon excursion method
prior to active simulations,
26
were used as custom
inputs. Lower bounds on muscle forces were chosen
according to values for minimum muscle activity
obtained from EMG,
27
and upper bounds on muscle
forces were defined as the product of muscle physi-
ological cross-sectional area
28
and specific muscle
tension
29
(Table 1).
In vitro simulations
Six cycles of each planar wrist motion, including
flexion-extension (FE), 50flexion to 30extension
to 50flexion (FE-5030) and radioulnar deviation
(RUD), 15ulnar deviation to 15radial deviation to
15ulnar deviation (RUD-15), were simulated on
intact specimens with the hand in the vertically up-
ward orientation (Fig. 1).
This was followed by trapeziectomy, performed by
excising the trapezium, intact or in a piecemeal
fashion, using a Wagner volar-radial approach.
2
Care
was taken to avoid the disruption of the distal tendons
insertions of APL and FCR on the first and second
metacarpals, respectively. Following the removal of
the trapezium, the joint capsule and superficial tissue
were carefully sutured (Ethibond Excel 2-0; Ethicon
Inc., Bridgewater, NJ), and active cyclic wrist mo-
tions were simulated on all specimens (Table 2).
Three types of surgical reconstructions post-
trapeziectomy were sequentially performed in order to
fill the gap created by the removal of the trapezium—
suture suspension arthroplasty
30
in 9 specimens,
prosthetic replacement
10
in 7 specimens, and LRTI
11
in 6 specimens. Suture suspension arthroplasty was
performed as described by DelSignore and Accardi,
30
with the first metacarpal stabilized by suture slings
(Ethibond Excel 0) between the FCR and the APL. A
silicone implant (Tie-In Trapezium Implant; Wright
Medical Technology Inc, Memphis, TN) was used as
the prosthetic replacement, with the arthroplasty per-
formed according to manufacturer guidelines. To
stabilize the implant, the distal tendon of the FCR was
split longitudinally into 2 portions to the base of the
index metacarpal, with 1 portion resected at the
musculotendinous junction, brought out into the gap
left after resecting the trapezium, and tied around the
waist of the implant, as prescribed by Avisar et al.
10
The LRTI was performed according to the technique
developed by Scheker and Boland,
11
and employed
the previously retracted portion of the distal tendon of
the FCR to stabilize the first metacarpal.
Following each of the surgical reconstructions
post-trapeziectomy, the joint capsule and surrounding
tissues were carefully sutured (Ethibond Excel 2-0)
before simulating cycles of wrist motions.
Data analysis
Each specimen was moved through 6 cycles for all
wrist motions. The first cycle was neglected to avoid
any transient effects at the beginning of the motion,
and the mean of the remaining 5 cycles was used for
data analysis. Mean muscle forces across all speci-
mens evaluated as a function of joint kinematics at
every 10in FE and 5in RUD, as well as the mean
and peak muscle forces over the entire range of
motion for all specimens, were computed for each
surgical reconstruction and compared with values
obtained for intact specimens. When checked for
normality using the Shapiro-Wilk test, the force data
were found to deviate from the normal distribution.
Therefore, nonparametric tests were used to compare
the data. The Friedman test was performed to deter-
mine differences between muscle forces obtained
during active motions simulated across the intact and
the various surgically reconstructed conditions (P<
.05). If significant interactions were observed in the
FIGURE 1: Schematic of the physiological wrist simulator.
EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS 391
J Hand Surg Am. rVol. 45, May 2020
TABLE 2. Peak Forces and Mean Forces of All Tendons During Cyclic Wrist Motions*
Cases
Peak Force (N)
FCR FCU ECRL ECRB ECU APL
FE-5030
Intact 39.3 7.5 27.1 7.9 30.9 10.9 57.1 15.8 65.9 6.0 26.5 10.1
Trap. 47.7 14.2 28.8 8.1 33.7 12.7 57.2 13.2 61.3 7.0 37.5 19.9
SSA 44.6 12.7 28.2 8.2 32.4 11.6 59.1 12.9 62.7 4.3 30.3 12.8
PR 44.2 8.5 29.4 8.9 30.7 9.5 58.9 13.9 64.2 5.6 17.9 –4.5
LRTI 39.1 10.4 30.0 10.0 33.0 7.8 60.9 13.2 64.9 5.8 27.1 13.5
RUD-15
Intact 25.4 8.6 29.6 8.1 22.3 6.4 37.7 13.7 59.6 10.9 30.8 14.1
Trap. 30.2 –10.1 31.0 8.0 23.9 6.2 38.3 13.4 55.1 14.5 40.2 20.8
SSA 25.3 8.5 30.1 8.3 21.6 5.6 37.4 10.1 58.0 12.5 40.9 13.0
PR 29.2 10.9 31.1 7.0 21.1 5.1 39.7 15.0 60.2 13.4 18.8 –6.3
LRTI 20.6 6.8 29.1 5.7 21.7 6.0 41.7 14.5 61.0 11.3 34.3 17.4
Cases
Mean Force (N)
FCR FCU ECRL ECRB ECU APL
FE-5030
Intact 19.9 3.5 16.2 3.1 17.6 3.8 32.6 6.3 42.6 5.1 14.4 4.2
Trap. 24.0 6.9 17.1 4.2 19.1 5.7 32.5 6.1 42.8 7.4 17.3 5.3
SSA 23.2 5.6 16.7 3.5 18.6 4.9 33.7 5.9 43.6 6.1 16.3 3.6
PR 23.2 5.5 17.0 3.7 17.5 4.4 33.4 6.6 44.0 6.3 11.7 1.8
LRTI 21.2 4.8 16.6 4.2 18.3 3.4 34.0 5.7 43.4 5.1 14.3 3.9
RUD-15
Intact 15.7 3.9 16.7 2.3 15.0 3.6 26.8 8.2 37.4 5.8 15.9 4.4
Trap. 17.7 –4.6 18.1 3.3 15.5 3.5 25.9 7.6 32.8 –6.7 15.6 4.4
SSA 16.0 4.5 17.4 3.1 14.4 3.1 26.1 6.5 36.2 7.0 18.7 3.8
PR 17.2 5.3 18.1 1.9 13.7 2.9 27.3 9.7 35.1 –6.1 11.6 –2.2
LRTI 13.7 3.6 17.9 2.6 14.0 3.3 28.7 9.5 37.0 5.3 16.6 4.8
PR, prosthetic replacement; SSA, suture suspension arthroplasty; Trap., trapeziectomy.
*Data are represented as mean 1 SD across specimens. Bold text indicates statistically significant differences between a surgical reconstruction
and the intact case (P<.01).
TABLE 1. Bounds on Tendon Forces
Muscle Lower Bound (N)
Physiological Cross-Sectional
Area
28
[A] (cm
2
)
Specific Muscle
Tension
29
[B] (N/cm
2
) Upper Bound [A*B] (N)
FCR 10 3.9 25 97.5
FCU 10 6.6 25 165.0
ECRL 10 2.5 25 62.5
ECRB 10 2.7 25 67.5
ECU 10 2.3 25 57.5
APL 10 1.7 25 42.5
392 EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS
J Hand Surg Am. rVol. 45, May 2020
Friedman test, a post hoc analysis was performed
using the Wilcoxon signed-rank test, with a Bonfer-
roni adjustment for multiple comparisons, to observe
pairwise differences within groups (P<.01). Dif-
ferences in muscle forces larger than 10% were
considered clinically important. With differences in
muscle forces between the intact state and the surgi-
cally altered state estimated at 5 N from our previous
work using the same experimental protocol,
31
the
sample size estimate was that 6 specimens were
sufficient to detect statistically significant differences
(P<.05) with a power of 80%.
RESULTS
While simulating FE-5030 after performing tra-
peziectomy (Fig. 2), the APL force was higher by
112% at 50flexion (P<.01) compared with that
from the intact specimens. No differences were
observed in mean and peak forces of the FCR, FCU,
ECRL, ECRB, and ECU following trapeziectomy. In
the case of RUD-15 following trapeziectomy (Fig. 2),
the FCR force was higher by 18% (P<.01), and that
of the ECU was lower by 24% (P<.01) at 15radial
deviation. No differences were observed in mean and
peak forces of the FCU, ECRL, ECRB, and APL
following trapeziectomy.
For FE-5030 after performing suture suspension
arthroplasty post-trapeziectomy (Fig. 3), the APL
force was higher by 40% at 50flexion (P<.01),
compared with that from the intact specimens. No
differences were observed in mean and peak forces of
the FCU, ECRL, ECRB, and ECU following suture
suspension arthroplasty. In the case of RUD-15
(Fig. 3), no differences were observed when
comparing the suture suspension arthroplasty with the
intact values for mean and peak forces of any muscle
throughout the range of motion.
In the case of inserting the silicone implant post-
trapeziectomy (Fig. 4), the peak APL force was lower
by 32% (P<.01) during FE-5030, compared with
that from the intact specimens. No differences were
observed in mean and peak forces of the FCR, FCU,
ECRL, ECRB, and ECU following the implant
insertion. In the case of RUD-15 following implant
insertion (Fig. 4), the forces of APL and ECU were
lower by 33% (P<.05) and 21% (P<.01)
respectively, at 15radial deviation. No differences
were observed in peak forces of the FCR, FCU,
ECRL, and ECRB following implant insertion.
FIGURE 2: Mean muscle forces of the APL, FCR, and ECU across 9 specimens during FE-5030 and RUD-15 in the intact specimens
(dashed lines) and following trapeziectomy (solid lines). Error bars represent 1 SD. The asterisk (*) represents statistically significant
differences between trapeziectomy and intact cases (P<.01).
EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS 393
J Hand Surg Am. rVol. 45, May 2020
In the case of FE-5030 and RUD-15 performed
following LRTI post-trapeziectomy (Fig. 5), no dif-
ferences were observed for mean and peak forces of
any muscle throughout the ranges of motion
compared with that from the intact specimens.
DISCUSSION
A validated physiological wrist simulator
23
was used
to measure the alterations to wrist biomechanics
caused by surgical reconstructions employed in the
treatment of trapeziometacarpal osteoarthritis. Wrist
motions were replicated in vitro using a control
strategy previously shown to have low kinematic
error and high repeatability.
23,25
Results from multi-
ple cyclic wrist motions simulated in the specimens
before and after trapeziectomy showed significant
changes in the wrist muscle force distribution. Owing
to the absence of any external loading or nonextreme
ranges of motion during the cadaveric simulations,
differences in muscle forces observed between the
intact condition and the postreconstruction were
considered clinically important if they differed in
magnitude by 10% and were statistically significant.
The removal of the trapezium resulted in a mean
rise of 112% (range, 50%e210%) in APL force for
high flexion angles (Fig. 2). This could be attributed to
the proximal migration of the APL insertion on the
base of the first metacarpal following trapeziectomy,
leading to a decrease in the moment arm of the APL
tendon about the FE axis of the wrist, thereby neces-
sitating a higher force to generate the same balancing
torque. The APL has the propensity to cause the
greatest dorsoradial misalignment of the first meta-
carpal at the trapeziometacarpal joint, owing to the
large resultant moment created by its point of insertion
and line of action.
32
This rise in APL force could
potentially cause radial subluxation of the pseudarth-
rosis between the first metacarpal and the scaphoid
during wrist motions involving deep flexion, which
could eventually lead to the dislocation or degenera-
tion resulting in pain, as is reported clinically.
5
Moreover, significant alterations in the wrist muscle
forces during certain wrist motions—for instance,
higher forces of APL and ECU during flexion, or
higher FCR forces coupled with lower ECU forces
during radial deviation (Fig. 2)—could result in lower
ranges of motion owing to pain or muscle fatigue, as
well as altered carpal biomechanics.
In our in vitro study, the biomechanical analysis
reflected the results of the surgical reconstruction
FIGURE 3: Mean muscle forces of the APL, FCR, and ECU across 9 specimens during FE-5030 and RUD-15 in the intact specimens
(dashed lines) and following suture suspension arthroplasty (solid lines). Error bars represent 1 SD. The asterisk (*) represents sta-
tistically significant differences between suture suspension arthroplasty and intact cases (P<.01).
394 EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS
J Hand Surg Am. rVol. 45, May 2020
immediately after it was performed, as opposed to
clinical studies, which are conducted several weeks
after surgery.
13,19
However, the significant post-
surgical alterations in muscle forces reflected in this
study, observed especially during limited range of
motion simulations without external loading, could
explain clinically important outcomes over a longer
period of time. Hence, these alterations should be
taken into consideration when selecting treatment for
younger patients.
Surgical reconstructions post-trapeziectomy were
performed in the same sequence on each specimen.
Suture suspension arthroplasty was selected as the
first reconstruction post-trapeziectomy because it was
least invasive than the 2 other reconstructions. In
contrast, the stem of the silicone implant required a
longitudinal hole to be drilled in the metacarpal,
10
which was eventually used as 1 of the tunnels
required for the LRTI procedure.
11
Moreover, the
portion of the distal FCR tendon retracted distally to
stabilize the silicone implant
10
was reused to fill the
trapezial gap in the LRTI procedure.
11
Thus, the ef-
fect of simulating multiple surgical reconstructions
on the outcome of the experiment was expected to be
minimal because the sequence of surgical
reconstructions was carefully chosen such that inva-
sive steps, such as drilling the bone, from a previous
reconstruction were used for the following one.
Whereas trapeziectomy and suture suspension
arthroplasty were performed on all specimens, pros-
thetic replacement and LRTI could not be tested on 2
and 3 specimens, respectively, owing to experi-
mental, surgical, and temporal challenges resulting
from the sequential nature of the protocol.
Surgical reconstructions performed post-
trapeziectomy perturbed the wrist muscle forces to
varying degrees compared with the intact condition.
Suture suspension arthroplasty was efficient in
restoring wrist muscle forces to the intact state in
RUD, but not in FE (Fig. 3). This reconstruction has
been suggested as having merit based on its attributes
such as being a less-invasive as well as a faster
procedure than using a prosthetic replacement or
LRTI
18
; however, the suture slings were probably
unable to prevent the proximal migration of the first
metacarpal during active wrist motions, thereby
resulting in higher forces in FE.
30
A reduction in APL
force following prosthetic replacement, despite using
a silicone implant of the same size for all specimens,
could suggest a partial restoration of the APL
FIGURE 4: Mean muscle forces of the APL, FCR, and ECU across 7 specimens during FE-5030 and RUD-15 in the intact specimens
(dashed lines) and following prosthetic replacement (solid lines). Error bars represent 1 SD. The asterisk (*) represents statistically
significant differences between prosthetic replacement and intact cases (P<.01).
EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS 395
J Hand Surg Am. rVol. 45, May 2020
insertion and tendon moment arm by filling the tra-
pezial void; however, there was an associated in-
crease in FCR force, especially in FE (Fig. 4). In
contrast, LRTI resulted in muscle forces similar to
those obtained in the intact case (Fig. 5), potentially
by providing a biomechanically efficient trapezial gap
restoration.
Notwithstanding their varying success in restoring
joint biomechanics in vitro, these procedures have
been proven to have certain limitations clinically.
17
Despite LRTI being a preferred surgical reconstruc-
tion, owing to the additional suspension support
provided by this technique,
14
several clinical studies
have reported no functional benefit of LRTI post-
trapeziectomy.
13,15,16,19
The in vitro study by Luria et al
22
reported LRTI to
be less efficient than prosthetic implants in preventing
the proximal migration of the first metacarpal, while
also suggesting that LRTI had no biomechanical
advantage over stand-alone trapeziectomy. These
outcomes contrast with the observations made in our
study and may have arisen from the difference in the
surgical procedures in each study—while Luria
et al
22
replicated the LRTI technique suggested by
Burton and Pellegrini,
33
a more recently proposed
reconstruction by Scheker and Boland
11
was imple-
mented in our study, which included a sturdier tendon
interposition technique specifically to prevent the
proximal migration of the first metacarpal. The
improved stabilization of the first metacarpal might
have aided the restoration of the wrist muscle forces
in vitro. Moreover, this reconstruction facilitated the
preservation of a portion of the distal FCR tendon,
thereby avoiding inherent biomechanical alterations
in the joint owing to the absence of the FCR.
31
There were limitations to this study. First, only 6
muscles inserting on the metacarpals were actuated to
simulate wrist motions in vitro.In vivo, extrinsic
muscles of the hand—such as flexor digitorum
superficialis, flexor digitorum profundus, flexor pol-
licis longus, and extensor digitorum communis—
would also contribute to wrist torque. In addition to
the extrinsic muscles, active actuation of the intrinsic
muscles of the thumb would facilitate the simulation
of isolated motions of the trapeziometacarpal joint
and should be included in future experiments. Sec-
ond, finite cycles of planar wrist motions were
simulated on an unloaded joint. Simulating multiple
cycles of complex wrist motions or implementing
cyclic loading might result in effects such as implant
FIGURE 5: Mean muscle forces of the APL, FCR, and ECU across 6 specimens during FE-5030) and RUD-15 in the intact specimens
(dashed lines) and following LRTI (solid lines). Error bars represent 1 SD. The asterisk (*) represents statistically significant differences
between LRTI and intact cases (P<.01).
396 EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS
J Hand Surg Am. rVol. 45, May 2020
loosening or even knot loosening in the case of LRTI.
Third, the analysis in this study was based on resto-
ration of wrist muscle forces. Other biomechanical
parameters, such as joint laxity, narrowing of the joint
space, tendon excursions, and joint contact forces,
could be quantified in future. Moreover, tracking the
kinematics of individual carpal bones would enable a
deeper insight into other wrist pathologies that may
occur following trapeziectomy, such as dorsal inter-
calated segment instability.
34
In conclusion, leaving the trapezial gap unfilled
after trapeziectomy resulted in altered muscle forces
during planar wrist motions, which could have im-
plications for carpal and wrist biomechanics over
time. Although clinical studies comparing LRTI with
trapeziectomy suggest no clinical difference, cor-
recting the biomechanics may improve outcomes in
the younger high-demand patient. With varying suc-
cess of surgical reconstructions post-trapeziectomy to
stabilize the first metacarpal, further research is
required to identify the ideal treatment for tra-
peziometacarpal osteoarthritis.
ACKNOWLEDGMENTS
We thank Michael H. Elvey, MBBS, BSc, Br Dip
Hand Surg, for his valuable inputs during the prep-
aration of the manuscript. This research was partially
supported by research grants from the Royal Society
(grant reference, RG130400) and Arthritis Research
UK (grant reference, 20556). D.S.S. was supported
by the Imperial College London PhD Scholar Pro-
gramme. These sponsors had no role in the study
design or the writing of the manuscript or the deci-
sion to submit the manuscript for publication.
Ethical approval was obtained from the Tissue
Management Committee of the Imperial College
Healthcare Tissue Bank, according to the Human
Tissue Act.
REFERENCES
1. Pai S, Talwalkar S, Hayton M. Presentation and management of
arthritis affecting the trapezio-metacarpal joint. Acta Orthop Belg.
2006;72(1):3e10.
2. Gervis WH. Excision of the trapezium for osteoarthritis of the
trapezio-metacarpal joint. J Bone Joint Surg Br. 1949;31B(4):
537e539.
3. Bakri K, Moran SL. Thumb carpometacarpal arthritis. Plast Reconstr
Surg. 2015;135(2):508e520.
4. Garcia-Elias M, Andres Tandioy-Delgado F. Modified technique for
basilar thumb osteoarthritis. J Hand Surg Am. 2014;39(2):362e367.
5. Conolly WB, Rath S. Revision procedures for complications of
surgery for osteoarthritis of the carpometacarpal joint of the thumb.
J Hand Surg Br. 1993;18(4):533e539.
6. Swanson AB. Disabling arthritis at base of thumb—treatment by
resection of trapezium and flexible (silicone) implant arthroplasty.
J Bone Joint Surg Am. 1972;54(3):456e471.
7. Vitale MA, Taylor F, Ross M, Moran SL. Trapezium prosthetic
arthroplasty (silicone, artelon, metal, and pyrocarbon). Hand Clin.
2013;29(1):37e55.
8. Creighton JJ, Steichen JB, Strickland JW. Long-term evaluation of
Silastic trapezial arthroplasty in patients with osteoarthritis. J Hand
Surg Am. 1991;16(3):510e519.
9. Weilby A. Resection arthroplasty of the first carpometacarpal joint.
J Hand Surg. 1979;4(6):586e588.
10. Avisar E, Elvey M, Tzang C, Sorene E. Trapeziectomy with a tendon
tie-in implant for osteoarthritis of the trapeziometacarpal joint.
J Hand Surg Am. 2015;40(7):1292e1297.
11. Scheker L, Boland M. Dynamic suspension-sling arthroplasty with
intermetacarpal ligament reconstruction for the treatment of tra-
peziometacarpal osteoarthritis. Eur J Plast Surg. 2004;27(4):
185e193.
12. Sirotakova M, Figus A, Elliot D. A new abductor pollicis longus
suspension arthroplasty. J Hand Surg Am. 2007;32(1):12e22.
13. Field J, Buchanan D. To suspend or not to suspend: a randomised
single blind trial of simple trapeziectomy versus trapeziectomy and
flexor carpi radialis suspension. J Hand Surg Eur Vol. 2007;32(4):
462e466.
14. Wolf JM, Delaronde S. Current trends in nonoperative and operative
treatment of trapeziometacarpal osteoarthritis: a survey of US hand
surgeons. J Hand Surg Am. 2012;37(1):77e82.
15. Davis T, Brady O, Dias J. Excision of the trapezium for osteoarthritis
of the trapeziometacarpal joint: a study of the benefit of ligament
reconstruction or tendon interposition. J Hand Surg Am. 2004;29(6):
1069e1077.
16. Davis T, Brady O, Barton N, Lunn P, Burke F. Trapeziectomy alone,
with tendon interposition or with ligament reconstruction? A ran-
domized perspective study. J Hand Surg Br. 1997;22(6):689e694.
17. Belcher H, Nicholl J. A comparison of trapeziectomy with and
without ligament reconstruction and tendon interposition. J Hand
Surg Br. 2000;25(4):350e356.
18. Weiss AC, Kamal RN, Paci GM, Weiss BA, Shah KN. Suture sus-
pension arthroplasty for the treatment of thumb carpometacarpal
arthritis. J Hand Surg Am. 2019;44(4):296e303.
19. Downing N, Davis T. Trapezial space height after trapeziectomy:
mechanism of formation and benefits. J Hand Surg Am. 2001;26(5):
862e868.
20. Downing N, Davis T. Osteoarthritis of the base of the thumb. Curr
Orthop. 2001;15(4):305e313.
21. Imaeda T, Cooney WP, Niebur GL, Linscheid RL, An K. Kinematics
of the trapeziometacarpal joint: a biomechanical analysis comparing
tendon interposition arthroplasty and total-joint arthroplasty. J Hand
Surg Am. 1996;21(4):544e553.
22. Luria S, Waitayawinyu T, Nemechek N, Huber P, Tencer AF,
Trumble TE. Biomechanic analysis of trapeziectomy, ligament
reconstruction with tendon interposition, and tie-in trapezium implant
arthroplasty for thumb carpometacarpal arthritis: a cadaver study.
J Hand Surg Am. 2007;32(5):697e706.
23. Shah DS, Middleton C, Gurdezi S, Horwitz MD, Kedgley AE. The
effects of wrist motion and hand orientation on muscle forces: a
physiologic wrist simulator study. J Biomech. 2017;60:232e237.
24. Wu G, van der Helm F, Veeger H, et al. ISB recommendation on
definitions of joint coordinate systems of various joints for the
reporting of human joint motion—part II: shoulder, elbow, wrist and
hand. J Biomech. 2005;38(5):981e992.
25. Shah DS, Kedgley AE. Control of a wrist joint motion simulator: a
phantom study. J Biomech. 2016;49(13):3061e3068.
26. Garland AK, Shah DS, Kedgley AE. Wrist tendon moment arms:
quantification by imaging and experimental techniques. J Biomech.
2018;68:136e140.
27. Fagarasanu M, Kumar S, Narayan Y. Measurement of angular wrist
neutral zone and forearm muscle activity. Clin Biomech. 2004;19(7):
671e677.
28. Holzbaur KRS, Murray WM, Gold GE, Delp SL. Upper limb muscle
volumes in adult subjects. J Biomech. 2007;40(4):742e749.
EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS 397
J Hand Surg Am. rVol. 45, May 2020
29. Kent-Braun J, Ng A. Specific strength and voluntary muscle acti-
vation in young and elderly women and men. J Appl Physiol.
1999;87(1):22e29.
30. DelSignore JL, Accardi KZ. Suture suspension arthroplasty tech-
nique for basal joint arthritis reconstruction. Techn Hand Up Extrem
Surg. 2009;13(4):166e172.
31. Shah DS, Middleton C, Gurdezi S, Horwitz MD, Kedgley AE. Al-
terations to wrist tendon forces following flexor carpi radialis or
ulnaris sacrifice: a cadaveric simulator study. J Hand Surg Eur Vol.
2018;43(8):886e888.
32. Mobargha N, Esplugas M, Garcia-Elias M, Lluch A, Megerle K,
Hagert E. The effect of individual isometric muscle loading on the
alignment of the base of the thumb metacarpal: a cadaveric study.
J Hand Surg Eur Vol. 2016;41(4):374e379.
33. Burton RI, Pellegrini VD Jr. Surgical management of basal joint
arthritis of the thumb. part II. Ligament reconstruction with
tendon interposition arthroplasty. J Hand Surg Am. 1986;11(3):
324e332.
34. Yuan BJ, Moran SL, Tay SC, Berger RA. Trapeziectomy and carpal
collapse. J Hand Surg Am. 2009;34(2):219e227.
398 EFFECT OF TRAPEZIECTOMY ON WRIST BIOMECHANICS
J Hand Surg Am. rVol. 45, May 2020
