Keywords
arthrodesis - four-corner arthrodesis - capitolunate - fusion - wrist
Palabras clave
artrodesis - artrodesis cuatro esquinas - lunogrande - fusión - muñeca
Introduction
Motion-sparing surgical treatment of advanced degenerative osteoarthritis of the wrist,
secondary to a long standing scaphoid nonunion (scaphoid nonunion advanced collapse
[SNAC] wrists), consists of scaphoidectomy and a midcarpal fusion to stabilize the
midcarpal joint and to avoid the proximal migration of the capitate, or proximal row
carpectomy.[1] The compromise of the head of the capitate (stage III) prevents the use of proximal
row carpectomy, and the partial carpal fusions most commonly used are four-corner
arthrodesis and capitolunate arthrodesis, with or without excision of the triquetrum.[2]
Graner first described capitolunate arthrodesis in 1966 for the treatment of Kienböck
disease.[3] In 1984, Watson described capitolunate arthrodesis and four-corner arthrodesis for
the treatment of scapholunate advanced collapse (SLAC) wrists.[4] In the original paper by Watson, 3 of the 16 patients underwent a capitolunate arthrodesis,
with similar results in the 13 patients who underwent a four-corner arthrodesis. However,
despite good outcomes, this technique was discouraged for the treatment of SLAC or
SNAC wrists due to its high nonunion rate.[5]
After the introduction of compression screws as fixation hardware, the incidence of
reported nonunion has decreased.[6] Other advantages, such as a lesser need for bone grafting, have brought attention
to capitolunate arthrodesis as an alternative to four-corner arthrodesis.
Although Gaston et al reported a retrospective series of capitolunate arthrodesis
and compared it to four-corner arthrodesis, they used two antegrade lunocapitate compression
screws and the triquetrum was excised in the majority of the cases,[7] as in the series presented by Calandruccio.[2]
To the best of our knowledge, no case series of capitolunate arthrodesis with only
one antegrade screw have been reported.
The purpose of the present study is to evaluate the outcomes of scaphoidectomy and
capitolunate arthrodesis versus four-corner arthrodesis in patients with stage III
SNAC wrists, using one antegrade compression screw, and without performing excision
of the triquetrum in the capitolunate arthrodesis.
Methods
After approval of the present study from the institutional review board, 32 patients
with SNAC III wrists surgically treated from 2007 to 2015 were identified retrospectively
(20 patients who underwent four-corner arthrodesis, and 12 patients who underwent
capitolunate arthrodesis). All of the patients with SLAC wrists were excluded, and
those with SNAC wrists who had not undergone any of the stated techniques, and/or
with radiolunate compromise or ulnar translocation of the wrist, were excluded. One
of the patients of the capitolunate arthrodesis group was excluded due to inability
to complete the follow-up protocol. The remaining 31 patients agreed to participate
and were able to complete the follow-up. Of these, 11 underwent capitolunate arthrodesis,
and 20 underwent four-corner arthrodesis.
The mean follow-up period of all of the patients was 46.8 months, with a range between
19 and 97 months. The mean follow-up period of the four-corner arthrodesis and capitolunate
arthrodesis was of 49.5 months and of 41.9 months, respectively. There were no statistically
significant differences between the mean follow-up periods (p = 0.2).
In [Table 1], the demographics of the patients are shown. There were no significant differences
in terms of age or of high-demand percentage of patients.
Table 1
Demographics of four-corner arthrodesis and capitolunate groups of patients
|
Features
|
Four-corner arthrodesis
|
Capitolunate arthrodesis
|
p-value
|
|
Mean age (years old)[*]
|
46.5 (12.6)
|
40.54 (11.5)
|
0.298
|
|
Percentage of male gender
|
85%
|
81.8%
|
−
|
|
Percentage of right-handed
|
90%
|
100%
|
−
|
|
Percentage of right-sided injuries
|
60%
|
66.7%
|
−
|
|
High demand
|
66.7%
|
63%
|
0.868
|
|
Preoperative VAS[*]
|
4.2 (0.4)
|
3.2 (1.0)
|
0.012
|
Abbreviation: VAS, visual analogue scale.
* Age and VAS are expressed as mean (standard deviation).
Hand therapists, blinded to the procedure performed, evaluated the postoperative wrist
ranges of motion (ROMs) and grip strength. The postoperative outcomes of the patients
were measured through three subjective outcome scales: the visual analog scale (VAS),
the disabilities of the arm, shoulder, and hand (DASH) score, and the Mayo wrist score
(MWS). All of the postoperative complications, such as nonunion, hardware-related
problems, and conversion to wrist arthrodesis or to arthroplasty were recorded. Nonunion
was defined as the absence of bony consolidation on the radiographic evaluation, with
or without the presence of tenderness over the arthrodesis site on the physical examination.
In case any patient presented radiographic images consistent with nonunion, the diagnosis
was confirmed by a computed tomography (CT) scan.
A descriptive analysis of all of the variables included was performed, expressing
qualitative variables in absolute values and in percentages; and quantitative variables
as mean and standard deviation (SD), along with 95% confidence intervals (CIs).
The statistical analysis was performed using the Mann-Whitney test and the Fisher
exact test with IBM SPSS Statistics for Windows, Version 19.0 (IBM Corp., Armonk,
NY, USA).
The dorsal wrist approach consisted of a longitudinal incision on the skin, of the
opening of the fourth extensor compartment, and of the opening of the dorsal capsule
using a longitudinal incision. After the scaphoidectomy and of the removal of the
cartilage of the involved joints, the dorsal intercalated segmental instability (DISI)
deformity, if present, was corrected and the capitolunate fusion was performed using
a single antegrade headless Newclip Handmotion compression screw (Newclip Technics,
Nantes, France) ([Fig. 1]). The triquetrum was not excised in any of the patients. Bone grafts from the scaphoidectomy
were used in 7 patients. Additional radial styloidectomy was performed in 5 patients,
and posterior interosseous neurectomy in 7 patients. The criteria to perform the posterior
interosseous neurectomy depended on the preoperative pain reported by the patient,
being performed on those patients with intense pain in their SNAC wrist.
Fig. 1 Capitolunate arthrodesis. Posteroanterior X-ray showing capitolunate arthrodesis
with a antegrade compression screw in a patient with scaphoid nonunion advanced collapse
wrist 5 months postoperatively.
The four-corner arthrodesis was performed using the same approach. The fusion of the
lunate, capitate, hamate and triquetrum bones was performed using staples (3 patients),
a dorsal Spider plate (Smith & Nephew, London, UK) (8 patients), or headless Newclip
Handmotion compression screws (9 patients) ([Fig. 2]). Bone grafts from the scaphoidectomy were used in all of the patients. Additional
radial styloidectomy was performed in 4 patients, and posterior interosseous neurectomy
in 18 patients.
Fig. 2 Four-corner arthrodesis with a dorsal plate. Posteroanterior X-ray showing four-corner
arhtrodesis with a dorsal plate in a patient with scaphoid nonunion advanced collapse
wrist 3 months postoperatively.
Postoperative splinting for between 3 and 4 weeks was mandatory in all of the cases
that used screws for bony fusion. In patients with dorsal plate, the splint was used
for 6 weeks, and in patients with staples, for between 7 and 8 weeks.
All the patients attended routinely to therapy and active-assisted range of motion
(ROM) exercise was started just after the splint was removed. Passive ROM exercise
was initiated at 8 weeks postoperatively, unless there was tenderness over the arthrodesis
site or there was no evidence of radiographic bone healing.
Results
The functional outcome is summarized in [Tables 2] and [3]. There were no statistically significant differences between the groups in VAS,
DASH or MWS, ROM or grip strength.
Table 2
Results[*] of wrist functionality and outcome scales
|
Four-corner arthrodesis
|
Capitolunate arthrodesis
|
p-value
|
|
VAS
|
1.5 (0.8)
|
1.4 (1.3)
|
0.774
|
|
DASH
|
35.1 (17.3)
|
48.1 (33.1)
|
0.256
|
|
MWS
|
61.6 (20.7)
|
54.5 (29.3)
|
0.296
|
|
Flexion
|
37.5° (12.1°)
|
38.7° (9°)
|
0.877
|
|
Extension
|
27.3° (12.9°)
|
33.1° (12.3°)
|
0.031
|
|
Radial deviation
|
13.1° (7.6°)
|
14.5° (4.6°)
|
0.674
|
|
Ulnar deviation
|
20° (8.4°)
|
19.3° (10.2°)
|
0.912
|
|
Grip strength
|
30.5 kg (28.9 kg)
|
19.8 kg (24.1 kg)
|
0.296
|
Abbreviations: DASH, disabilities of the arm, shoulder, and hand questionnaire; MWS,
Mayo wrist scale; VAS, visual analogue scale.
* Results are shown as mean (standard deviation).
Table 3
Functional outcome[*]
|
Four-corner arthrodesis
|
Capitolunate arthrodesis
|
p-value
|
|
Flexion
|
58.6% (24.2)
|
61.4% (19.7)
|
0.359
|
|
Extension
|
50.0% (36.6)
|
65.7% (17.0)
|
0.060
|
|
Radial deviation
|
38.4% (22.3)
|
59.1% (39.4)
|
0.183
|
|
Ulnar deviation
|
44.5% (28.6)
|
46.2% (12.3)
|
0.583
|
|
Grip strength
|
62.51% (33.5)
|
58.7% (26.9)
|
0.133
|
|
Flexion-extension arc
|
52.3% (22.2)
|
55.2% (13.9)
|
0.145
|
|
Radioulnar deviation arc
|
41.4% (21.9)
|
51.1% (9.6)
|
0.066
|
|
Pronosupination
|
96.8% (0.8)
|
98% (1.3)
|
0.124
|
* Results are expressed as a percentage (standard deviation). The percentages result
from the comparison with the contralateral side of the injury.
The mean flexion-extension arc was 52.3% of the contralateral side for four-corner
arthrodesis, and 55.2% of the contralateral side for capitolunate arthrodesis. This
difference of 2.9% in flexion-extension means was not statistically significant (p = 0.145).
The radioulnar deviation arc averaged 41.4% of the contralateral side for four-corner
arthrodesis, and 51.1% of the contralateral side for capitolunate patients. The mean
difference of 9.7% between the 2 techniques was not statistically significant (p = 0.066).
The mean pronation-supination arc was 96.8% of the contralateral side for four-corner
arthrodesis, and 98% of the contralateral side for capitolunate arthrodesis. This
difference of 1.2% was not statistically significant (p = 0.124).
The mean grip strength was 62.5% of the contralateral side for four-corner arthrodesis,
and 58.7% of the contralateral side for capitolunate arthrodesis. This difference
of 3.8% was not statistically significant (p = 0.133).
Bone graft was needed in 7 patients of the capitolunate arthrodesis group (63.6%),
and in all of the patients of the four-corner arthrodesis group (100%). The donor
site of the bone graft was always the scaphoid bone from the scaphoidectomy.
Two patients in the four-corner arthrodesis group (10%), with a dorsal plate used
as the fixation hardware, presented with nonunion, compared with none in the capitolunate
arthrodesis group (0%), and this difference was not statistically significant (p = 0.409).
One patient in the four-corner arthrodesis group required removal of the dorsal plate
and tenolysis of the extensor tendons.
One patient in the four-corner arthrodesis group underwent a revision to total wrist
arthrodesis. The method of fixation used in the four-corner arthrodesis had been a
dorsal plate. One of the patients in the capitolunate arthrodesis group converted
to total wrist arthrodesis. None of the patients were revised to wrist arthroplasty.
Discussion
The present study found similar outcomes for four-corner arthrodesis and capitolunate
arthrodesis in patients with stage III SNAC wrists, using one antegrade compression
screw, and without performing excision of the triquetrum in the capitolunate arthrodesis.
These results are comparable to the findings of the recent literature on the subject.[7]
One of the remaining concerns about capitolunate arthrodesis is the long-term results.
The follow-up periods of the series of Kirschenbaum et al,[8] Calandruccio et al,[2] Goubier et al,[6] Hegazy,[9] and of Gaston et al[7] are of 36, 28, 29, 37, and 31 months, respectively. Durand et al reported a series
with 4 years of follow-up,[10] the same as in the present study, and Krakauer et al followed-up 8 patients for
50 months.[11] The study presented by Delclaux et al followed-up 12 patients with capitolunate
arthrodesis for 10 years.[12]
Another concern might be the small number of patients included on the aforementioned
series, which ranges from 8 to 20 patients, and might limit the power of the statistical
analysis to obtain significant differences when comparing capitolunate arthrodesis
with other techniques.
Regarding the functional outcome, and despite the fact that there were no significant
differences between the groups in flexion-extension, radioulnar deviation, or pronation-supination
arcs in our series, capitolunate arthrodesis achieved a greater ROM. The almost 10%
difference in radioulnar deviation between the 2 techniques was not statistically
significant (p = 0.066), but it may have clinical relevance. The ROM for capitolunate arthrodesis
patients is similar to the reported ROM in previous series.
However, the grip strength was better for the four-corner arthrodesis group (62.5%
of the contralateral side versus 58.7% for capitolunate arthrodesis), despite no significant
differences having been observed. In our series, the grip strength for capitolunate
arthrodesis (58.7%) was slightly lower than the reported in other series (60–80%).
Despite the fact that a bone graft was only harvested in 7 patients of capitolunate
fusion, no nonunions were found. However, the bone graft was harvested from the scaphoidectomy
in all of the patients of four-corner arthrodesis, and two patients presented with
nonunion. It must be noted that, in both cases of nonunion, the fixation hardware
was a Spider dorsal plate, which has been related to high nonunion rates of up to
62% in four-corner arthrodesis.[13]
[14] The fusion was also performed with a Spider dorsal plate in the case requiring tenolysis
and in the case converted to total wrist arthrodesis. None of the cases of four-corner
arthrodesis in which compression screws or staples were used for fixation presented
with nonunion.
One important limitation of the present study is the retrospective nature of the review.
This means that a possible selection bias would only be addressed in a prospective
randomized study. Other limitations are the small sample size, especially in the lunocapitate
group, which can be noted by the large SDs of the collected data, the lack of preoperative
data for comparison, the different techniques used in the four-corner arthrodesis
group, and also by the addition of posterior interosseous neurectomy and styloidectomy
in different percentages in the four-corner arthrodesis group versus the capitolunate
arthrodesis group, which could bias the overall results.
Despite these limitations, we present our technique for capitolunate arthrodesis with
one antegrade compression screw as a possible alternative to four-corner arthrodesis,
which has the advantages of reducing operative time and fixation hardware costs. In
addition, the nonunion rate in the present study is comparable to that of the study
of Gaston et al[7] who proposed the use of two antegrade compression screws.
Four-corner wrist arthrodesis is the classic method for the treatment of SNAC III
wrists over capitolunate arthrodesis due to the higher surface of bony union and,
as a consequence, to the lower expected nonunion rate. In addition, the concern about
proximal migration of the screws or progression of radiolunate degeneration in the
capitolunate arthrodesis makes the outcomes of this technique more unpredictable than
performing the endorsed four-corner arthrodesis.[15] However, the recent literature reports similar outcomes of capitolunate arthrodesis
versus four-corner arthrodesis. Contraindications for this technique are radiolunate
compromise and ulnar translocation of the wrist.[9]
The main complications of four-corner arthrodesis are nonunion (5.5%), hardware-related
complications (3.3%), and dorsal impingement or lunate malposition (2.6%).[9]
[10]
[11]
[12] The complications may be related to the surgical technique, to the quality of the
bone grafting, and to the fixation hardware used. Consequently, the literature demonstrates
variable nonunion rates in a series of four-corner arthrodesis performed with dorsal
plate.[13]
The reported long-term results are a flexion-extension of 55% of the contralateral
side, grip strength of 80% of the contralateral side, and absence of pain in between
80 and 90% of the patients.[9]
[13]
[14]
[16]
The method of internal fixation described for four-corner arthrodesis involves Kirschner
wires, staples, screws and dorsal plates. The nonunion rate for the 1st 3 methods of fixation ranges from 3 to 18%, and in the case of dorsal plates, from
16 to 62%.[16]
[17]
[18] Headless compression screws are the recommended method for fixation in four-corner
arthrodesis.[7]
Since the original capitolunate technique was reported by Watson,[4] and despite the need of less bony graft compared with four-corner arthrodesis, the
initial reported nonunion rates associated with this procedure ranged from 33 to 50%
with Kirschner wires or staples.[19] Since the introduction of compression screws, the reported nonunion rates were drastically
reduced, reaching 8% in the series reported by Goubier et al[6] and by Delclaux et al,[12] and 0% in the series reported by Gaston et al and by Hegazy.[7]
[9] In addition, a shorter operative time and less dissection of the soft tissue make
this procedure an appealing alternative to four-corner arthrodesis.[19]
Regarding the functional outcome in capitolunate arthrodesis, flexion-extension was
reported to range between 48 and 53% of the contralateral side, and the grip strength
from 61 to 70%[8]
[18]
Some technical refinements have been proposed, such as excision of the triquetrum
to avoid ulnar impaction, although increasing radiolunate contact.[8]
[18] Excision of the triquetrum was also reported in type II lunate, to avoid pisotriquetral
arthritis and to ease lunate reduction.[4] However, Ferreres et al established the importance of the preservation of the lunotriquetral
joint to maintain proprioception of the radiotriquetral ligaments.[1]
When treating the degenerative arthritis that follows scapholunate instability or
scaphoid pseudarthrosis, excision of the scaphoid must be combined with a stabilization
of the midcarpal joint. Two alternatives have been proposed for that purpose: fusing
the lunate, the triquetrum, the capitate, and the hamate bones (four-corner fusion)
or limiting the arthrodesis to the lunate and capitate bones, preserving or excising
the triquetrum. Previous reports have attributed a high level of complications to
lunocapitate arthrodesis, mainly regarding nonunion. We have reviewed 11 patients
who had been treated with a lunocapitate fusion, with no removal of the triquetrum,
after a 4-year follow-up period, and found similar results compared with four-corner
arthrodesis, even with a major degree of motion in ulnar-radial deviation. A recent
work on the innervation of the radiotriquetral ligaments has given relevance to the
preservation of lunotriquetral motion in maintaining proprioception. Also, if the
triquetrum is excised to gain more motion, the proprioceptive role of the radiotriquetral
ligaments is compromised.
Even so, there is no randomly designed study to evaluate four-corner arthrodesis and
capitolunate arthrodesis in SNAC or SLAC wrists. The risk of bias in the evaluation
of capitolunate arthrodesis is based on the possibility of reserving the usage of
capitolunate arthrodesis to those patients with better bone stock and less risk of
developing nonunion based on the preoperative evaluation of the patient and on the
experience of the surgeon. In addition, the differences in the immobilization protocol
between groups could also affect the results.
Conclusions
Capitolunate arthrodesis remains an acceptable alternative to four-corner arthrodesis
as far as nonunion and postoperative complications in the short-term follow-up are
concerned. However, long-term prospective randomized studies are needed to compare
this technique with four-corner arthrodesis before capitolunate arthrodesis can be
considered a gold standard in the treatment of wrist osteoarthritis.
