Keywords
wrist arthroplasty - wrist prothesis - Motec
Introduction
Wrist arthroplasty is a procedure that emerged as an alternative to wrist arthrodesis
for cases of osteoarthritis of different causes. In several studies, results showing
a great reduction in pain and a subtle improvement in grip strength have been obtained
in both procedures, but with the possibility of maintaining a functional range of
motion in patients with prostheses.[1] Furthermore, the results of the arthroplasties were similar regardless of the indication
(scapholunate advanced collapse [SLAC], scaphoid non-union advanced collapse [SNAC],
distal radius fractures).[2]
Over time, the implants evolved, and currently they are in the fourth generation,
always with the aim of reducing the possibility of complications in relation to previous
models. The models currently used aim to improve the biomechanics of the joint and
minimize the amount of bone resection and the rate of carpal resection. In addition,
one of the recent potential solutions to prevent component loosening involves the
use of materials with greater potential for integrative bone ingrowth, especially
with respect to the distal component.[3]
The prostheses studied in previous works, such as Universal 2 (KMI, Carlsbad, CA,
United States) and Re-Motion (Stryker, Kalamazoo, MI, United States) have high rates
of complications and reported revisions, mainly due to causes such as loosening of
components[4]
[5]. A study with 56 patients who underwent wrist arthroplasty with the Motec (Swemac
Orthopaedics AB, Linköping, Sweden) prosthesis demonstrated an implant survival rate
of 86% after 10 years, and these results were encouraging.[6]
Bearing in mind that the Motec prosthesis may be indicated for cases of degenerative
osteoarthritis, (inflammatory) rheumatoid arthritis, and posttraumatic osteoarthritis
as a consequence of scapholunate dissociation, Kienböck disease, wrist fracture-dislocation,
intra-articular fractures of the distal radius, intercarpal fusions, and proximal
carpal row resection,[7] the objective of the present study is to describe the functional results and complication
rates in a series of cases operated by a single surgeon.
Materials and Methods
The present study involved 14 patients operated on between November 2018 and April
2022 at 2 hospitals in Barcelona by a single experienced hand surgeon. The patients
answered the Mayo Wrist Score questionnaire and the Visual Analog Scale (VAS) in the
preoperative period and sx months after the procedure. One patient was excluded for
having a follow-up of shorter than six months. The surgical technique ([Figure 1]) used was that recommended by the manufacturer of the Motec.[6]
Fig. 1 (1) Resection of the proximal row of the carpus. (2,3) Preparation and introduction of the distal component. (4,5) Preparation and introduction of the proximal component. (6) Final clinical appearance.
After the operation, the stitches were removed after 10 days, and after 2 weeks the
immobilization was changed from a dorsal plaster splint to a Velcro splint, which
was used up to 6 weeks postoperatively. Two weeks postoperatively, the patients were
referred to a specialized hand therapist, and rehabilitation with active movements
was started.
Follow-up was carried out through monthly face-to-face consultations with repeated
radiographs to assess complications.
Data were collected from the medical records in June 2022, and we searched for the
following variables: age, date of birth, gender, previous wrist pathology, duration
of the follow-up, Mayo Wrist Score and VAS scores preoperatively and six months after
surgery, and complications. Complications were defined as any sign of component loosening,
impact generated by the prosthesis, infection or need for revision.
The data were analyzed by calculating means and standard deviations (SDs) and a paired
sample t-test was used with the Statistical Package for the Social Sciences (IBM SPSS Statistics
for Windows, IBM Corp., Armonk, NY, United States) software, version 26.0, to compare
the pre- and postoperative results of the Mayo Wrist Score and VAS, considering values
of p < 0.05 statistically significant.
Results
In total, 14 patients were evaluated, 13 men and 1 woman, with a mean age of 64.8
(SD = 7.5) years. The mean duration of the follow-up was of 25.1 (SD = 10.9) months,
with a minimum of 6 and a maximum of 40 months.
Regarding the Mayo Wrist Score, the preoperative mean was of 23.2 (SD = 8.9) points,
and the postoperative mean was of 82.8 (SD = 7) points. The mean preoperative VAS
score was of 7.6 (SD = 1.1) points, while the mean postoperative score was of 1 (SD = 1.2)
point. The differences in the pre- and postoperative scores on both scales were statistically
significant (p < 0.001).
The variables of each patient are shown in [Table 1]. here were no intra- or postoperative complications during the follow-up.
Table 1
|
Patient
|
Age
|
Gender
|
Date of surgery
|
Previous situation of the joint
|
Follow-up (months)
|
MWS - pre
|
MWS - post
|
VAS - pre
|
VAS - post
|
|
1
|
53
|
M
|
11/2018
|
PRC
|
36
|
15
|
75
|
9
|
4
|
|
2
|
64
|
M
|
12/2018
|
Four-corner arthrodesis
|
40
|
20
|
80
|
7
|
2
|
|
3
|
71
|
M
|
02/2019
|
SLAC
|
36
|
25
|
90
|
9
|
0
|
|
4
|
58
|
M
|
05/2019
|
PRC
|
24
|
15
|
85
|
8
|
2
|
|
5
|
67
|
F
|
08/2019
|
Degenerative osteoarthritis
|
35
|
30
|
100
|
7
|
0
|
|
6
|
68
|
M
|
10/2019
|
Osteoarthritis – radius fracture
|
31
|
20
|
85
|
6
|
0
|
|
7
|
54
|
M
|
11/2019
|
Lunocapitate ARTHRODESIS
|
25
|
15
|
80
|
8
|
1
|
|
8
|
73
|
M
|
01/2020
|
Osteoarthritis – radius fracture
|
26
|
40
|
90
|
6
|
1
|
|
9
|
80
|
M
|
07/2020
|
SNAC
|
23
|
15
|
80
|
9
|
2
|
|
10
|
61
|
M
|
10/2020
|
PRC
|
19
|
20
|
85
|
6
|
0
|
|
11
|
68
|
M
|
01/2021
|
Four-corner arthrodesis
|
19
|
30
|
75
|
7
|
0
|
|
12
|
59
|
M
|
04/2021
|
Osteoarthritis – radius fracture
|
13
|
25
|
80
|
8
|
0
|
|
13
|
63
|
M
|
10/2021
|
Osteoarthritis – radius fracture
|
7
|
15
|
80
|
8
|
0
|
|
14
|
69
|
M
|
12/2021
|
SLAC
|
6
|
40
|
75
|
9
|
2
|
Discussion
The operated patients in our series had previous diagnoses of SLAC, SNAC, and posttraumatic
and degenerative radiocarpal osteoarthritis. In addition, other patients had already
undergone other surgeries, such as proximal carpectomy, lunocapitate arthrodesis or
four-corner arthrodesis ([Figure 2]). In accordance with the possible indications for the use of the Motec prosthesis,
the present study did not include cases of Kienböck disease, total wrist arthrodesis
(rearticulation),[8] and rheumatoid arthritis.[9]
Fig. 2 (7) Fracture of the scaphoid with scapholunate dissociation in a 56-year-old patient
(8) operated on 6 weeks later by another surgeon, and evolution with nonunion of the
scaphoid and DISI (Dorsal intercalated segment instability). (9) The patient arrived at our department after undergoing four-corner arthrodesis that
evolved with material failure. (10) We opted for revision of the arthrodesis with screws, but the patient still presented
pain 12 months after the last intervention. (11 and 12) We performed wrist arthroplasty, and the patient is asymptomatic after one year
of follow-up
There was a significant improvement in the Mayo Wrist Score and VAS score in our sample
6 months after the operation. Previous wrist arthroplasty case series studies with
longer follow-ups[10] and a systematic review[11] also showed improvements in these parameters, although they were performed with
the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire instead of the
Mayo Wrist Score.
No adverse events related to the prosthesis material, such as reactions to metal debris,[12] were observed in the period studied. Similarly, the patients did not present infection,
although some had risk factors such as posttraumatic osteoarthritis.[13]
To date, the loosening of components, a common failure factor,[14] has not been observed in our sample, thus eliminating the need for salvage surgeries,
previously described as extremely complex and difficult to perform.[15] In this regard, we must emphasize that one of the advantages of the Motec system
is the ease of reconversion to arthrodesis in case of failure, with results similar
to those of primary arthrodesis.[16]
The present study has a number of obvious limitations, such as a small sample size,
a median follow-up of just over 2 years (which was shorter than those of other studies,
which had follow-ups of 5 or 10 years), and that there were no measures of strength
or range of motion, even though they are clinically functional. However, it is a series
of cases operated on and followed up by the same surgeon, which can provide greater
uniformity to the results.
Conclusion
Wrist arthroplasty is a surgical option to treat cases of posttraumatic osteoarthritis
or as rescue from previous failed surgeries (proximal carpectomy or four-corner arthrodesis),
helping the patient maintain a functional range of motion. As observed in the present
series, the improvements in terms of function and pain were significant, with no major
complications occurring in the period evaluated, and wrist arthroplasty was able to
serve as a rescue for failed partial arthrodesis.
Obviously, to be able to draw firmer conclusions regarding the benefits or complications
of this prosthesis model, we must increase the number of patients studied, as well
as study them for longer periods.
