Keywords
four corner fusion - proximal row carpectomy - SLAC - SNAC - wrist arthritis
Proximal row carpectomy (PRC) and four-corner arthrodesis (4CA) are considered motion-sparing
procedures for various etiologies of wrist arthritis. Although indications for each
are not completely aligned, the surgeon is often tasked with deciding between these
options which vary in the surgical technique and complication profile. Aggregate reporting
has identified nonunion as a common complication following 4CA[1]
[2]
[3]
[4] and limitations in grip strength complicate PRC due to an altered length–tension
relationship of the flexors.[1]
[5]
[6]
Patient age continues to be a conundrum in determining the most appropriate treatment
in cases of wrist arthritis. Although patient age is often discussed as a determining
factor between 4CA and PRC, results are infrequently stratified by age. Wagner et
al[6] reported similar outcomes between 4CA and PRC for a series of patients aged 45 years
and under. DiDonna et al[7] concluded that PRC patients under 35 years had a significantly increased risk of
radiocapitate pathology which may translate into worsening clinical outcomes. Whether
these findings are representative of the aggregate literature is unknown.
Previous systematic reviews reporting outcomes for 4CA and PRC provided datasets with
a mean patient age between 45 and 50 years but the age ranges are widely distributed.[2]
[4]
[8]
[9]
[10]
[11] Physiologic aspects of healing and recovery are not uniform across a large age distribution.
Thus, treatment decisions should be evaluated within the confines of a more narrow
age bracket to provide a template for informed clinical decision-making.
Our objective was to perform a systematic review on the age-specific clinical outcomes
for PRC and 4CA. These data intended to determine whether outcomes differed between
younger and older age groups and whether 4CA or PCR yielded superior outcomes between
these age groups.
Materials and Methods
Search Strategy
A PubMed database search was performed on October 05, 2023 according to the Preferred
Reporting Items for Systematic Reviews and Meta-analysis guidelines. The following
search terms were used: “proximal row carpectomy,” “four corner arthrodesis,” “four
corner fusion,” “4 corner arthrodesis,” “4 corner fusion,” “scaphoid nonunion advanced
collapse,” and “scapholunate advanced collapse.”
Eligibility Criteria
The population, intervention, comparison, and outcome characteristics for eligibility
were the following:
-
P—adults over the age of 18 years.
-
I—treated with PRC and 4CA for all indications.
-
C—clinical outcomes between these interventions were compared.
-
O—age groups were delineated for outcome comparison.
The inclusion criteria required individual case reporting of patient age, surgical
intervention, and appropriate outcome measures.[12] Three or more cases per report were required for inclusion.
Data Collection
The following case data were extracted from each included article: patient age, patient
gender, indication for surgical intervention, follow-up term, visual analog score
for pain, disabilities of the arm, shoulder, and hand (DASH) score, grip strength
expressed as a percentage of the contralateral side, wrist arc of motion, nonunion,
hardware removal for 4CA cases, radiographic radiocapitate narrowing for PRC cases,
and revision surgery. For outcomes without standardized parameters, a reasonable interpretation
of the provided verbiage was made to ensure continuity in aggregation. The lack of
revision or removal surgery was not presumed due to the absence of verbiage stating
the presence of these secondary procedures. When radiocapitate narrowing was reported
using specified criteria, the data were aggregated using a binary protocol of present
for moderate/severe arthrosis or partial/complete narrowing and absent for none/minimal.
Data Grouping
The data were stratified by procedure and by patients older than and younger than
45 years. The age of 45 years was chosen to maintain consistency with the prior work
by Wagner et al[6] which compared results between 4CA and PRC in patients under 45 years. Although
the Wagner et al article did not provide individual case reporting, it was included
in aggregate analysis due to the entirety of the series aligning with the under 45
years age group.
Data Analysis
Clinical outcomes were compiled as means and then compared between groups using the
two-sample t-test and Fisher's exact test. Due to disparate sample sizes, some data were presented
with and without the Wagner et al[6] article. For DASH scores, results were stratified as scores above and below 30.
This score was chosen based on the approximate mean for previous reviews on 4CA and
PRC.[1]
[4]
[8]
[9] The Wagner et al[6] article was not included in this analysis due to a lack of individual case scores.
Risk of Bias
The Cochrane ROBINS-I (risk of bias in non-randomized studies of interventions) provides
the following domains for evaluation: confounding, selection of participants, classification
of interventions, deviation from intended interventions, missing data, measurement
of outcomes, and selection of reported results.[13] For all included studies, each domain was graded as low, moderate, or severe risk,
and then, a final grade was given which corresponded to the highest level of risk
across the domains.
Quality Assessment
The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) framework
provided the following factors for the evaluation of research quality: limitations,
inconsistency, indirectness, imprecision, and publication bias.[14] A binary scale for serious limitations was used for each factor across the outcomes
of interest.
Results
Search Results
Following irrelevant exclusions, 132 articles were screened by full text ([Fig. 1]). Of those, 55 were excluded due to a lack of individual case reporting. Twenty-five
articles met the inclusion criteria with 207 cases in the 4CA group (mean follow-up
50 ± 67 months) and 171 cases in the PRC group (mean follow-up 79 ± 64 months; [Table 1]).
Fig. 1 Flowchart depicting literature search and article retrieval, noting criteria for
full text exclusions.
Table 1
Cochrane risk of bias ROBINS-I (risk of bias in nonrandomized studies of interventions)
for review of four corner arthrodesis and proximal row carpectomy
|
|
Note: + indicates low risk of bias, ? indicates moderate risk, and - indicates serious
risk.
Bias and Quality Assessment
There was a moderate risk of bias in at least one domain for all included articles
([Table 2]). This finding indicates that each study cannot be considered comparable to a well-performed
randomized trial.[13]
Table 2
An adapted Grading of Recommendations Assessment, Development and Evaluationsummarization
for review of four corner arthrodesis and proximal row carpectomy
|
Limitations
|
Inconsistency
|
Indirectness
|
Imprecision
|
Publication bias
|
|
Procedure groups
|
I/II LoE[a]
|
Risk of bias
|
Outcomes
|
Outcomes
|
Sample size
|
Outcomes
|
|
Four corner arthrodesis
|
2/14[a]
|
✓
|
✗
|
✗
|
✓
|
✓
|
|
Proximal row carpectomy
|
0/12[a]
|
✓
|
✗
|
✗
|
✓
|
✓
|
a One study is included in both groups: ✓—serious limitations, ✗—no serious limitations.
Within the GRADE framework, articles were grouped based on the reported procedure.
There were two articles with the I/II level of evidence—both in the 4CA group ([Table 3]). There were serious limitations for the risk of bias, sample size, and publication
bias for articles in the 4CA and PRC groups.
Table 3
Case characteristics for included studies reporting on four corner arthrodesis and
proximal row carpectomy stratified into age groups
|
Patient age
|
Studies
|
Cases
|
Age (y)[a]
|
Gender (m)[a]
|
Follow up term (mo)[a]
|
|
Four corner arthrodesis
|
|
Under 45 y
|
14
|
143
|
36.9
|
90%
|
47.5
|
|
Over 45 y
|
10
|
64
|
60.6
|
80%
|
52.9
|
|
Proximal row carpectomy
|
|
Under 45 y
|
11
|
112
|
37.1
|
91%
|
95.3
|
|
Over 45 y
|
10
|
59
|
58.8
|
70%
|
78.1
|
a Age in years, gender in male, follow-up in months.
Clinical Outcomes
Mean DASH scores, grip strength, and postoperative arc of wrist flexion and extension
were similar between the 4CA and PRC groups ([Table 4]). The difference in DASH score between 4CA and PRC and between age groups did not
reach the established minimal clinically important difference.[15]
Table 4
Clinical outcomes for included studies reporting on four corner arthrodesis and proximal
row carpectomy stratified into age groups
|
Patient age
|
DASH[a]
|
Grip strength (% cl)[a]
|
Arc of motion (preoperative)[a]
|
Arc of motion (postoperative)[a]
|
|
Four corner arthrodesis
|
|
Under 45 y
|
21.5
|
74%
|
78 degree
|
67 degree
|
|
Over 45 y
|
20.2
|
70%
|
85 degree
|
76 degree
|
|
Significance
|
p = 0.84
|
p = 0.44
|
p = 0.76
|
p = 0.39
|
|
Proximal row carpectomy
|
|
Under 45 y
|
26.4
|
61%
|
65 degree
|
80 degree
|
|
Over 45 y
|
22.8
|
75%
|
67 degree
|
71 degree
|
|
Significance
|
p = 0.59
|
p = 0.17
|
p = 0.93
|
p = 0.32
|
Abbreviation: DASH, disabilities of the arm, shoulder, and hand.
a Disabilities of the arm, shoulder, and hand score, grip strength as a percentage
of the contralateral side, wrist flexion/extension arc of motion measured preoperative
and postoperative.
Within the 4CA group, the relative risk for a DASH score above 30 was 1.94 (95% CI,
1.1–3.67) in patients over 45 years compared with patients under 45 years ([Fig. 2]). Within the 4CA group, the rate of nonunion was similar between the age groups.
There was an increased rate of revision in the under 45 age group (7.8%) compared
with the over 45 age group (2.3%) which was significant (p = 0.041) with the inclusion of the Wagner et al study to the under 45 age group (13.7%;
[Table 5]).
Fig. 2 Graphical comparison of DASH scores distribution between younger and older adult
patients following four corner arthrodesis and proximal row carpectomy.
Table 5
Complications for included studies reporting on four corner arthrodesis and proximal
row carpectomy stratified into age groups
|
Patient age
|
Nonunion
|
Radiocapitate narrowing
|
Revision
|
|
Four corner arthrodesis
|
|
Under 45 y
|
6%/8.2%
|
|
7.8%/13.7%
|
|
Over 45 y
|
3.1%
|
|
2.3%
|
|
Significance
|
p = 0.70/0.35
|
|
p = 0.37/0.041
|
|
Proximal row carpectomy
|
|
Under 45 y
|
|
21%/28%
|
11.4%/17.8%
|
|
Over 45 y
|
|
43%
|
IR
|
|
Significance
|
|
p = 0.007/0.11
|
|
Abbreviation: IR, insufficient reporting.
Note: Nonunion and revision reported without/with the Wagner et al study, radiographic
evidence of radiocapitate pathology reported with 5 year/10 year results from Wagner
et al study.
Within the PRC group, grip strength as a percentage of the contralateral side was
higher in the over 45 age group (mean 75%) compared with the under 45 age group (mean
61%) but did not reach the level of significance. Within the PRC group, the rate of
radiocapitate joint disease was similar between the age groups, at a mean follow-up
of 87 months in the over 45 age group (43%) and 105 (21%) and 115 (28%) months in
the under 45 age group.
Discussion
Although the mean DASH scores following 4CA are comparable between patients under
and over 45 years, the distribution of scores is conspicuous. The current results
demonstrate an increased risk of disability based on DASH score following 4CA in patients
under 45 years compared to patients over 45 years. There was a nearly twofold increase
in risk of a DASH score above 30 in the younger adult group following 4CA. This finding
indicates an increased risk of continued pain and dysfunction in adults under 45 years
who are treated with 4CA compared with adults over 45 years.
Following PRC, patients over 45 years had greater recovery of grip strength compared
with patients under 45 years. This may be explained by a general decline in strength
with advancing age. Thus, the loss of strength may be more impactful and demonstrable
in younger adults. Grip strength is a commonly reported clinical outcome following
the treatment of wrist arthritis. Results between 4CA and PRC are conflicting across
the literature with reasonable postulates for both procedures yielding superiority
of grip strength. Laronde et al[16] reported superior grip strength in PRC compared with 4CA despite a significant loss
in carpal height in the PRC group. The review by Saltzman et al[1] found significantly superior grip strength following 4CA compared with PRC. Conversely,
the review by Amer et al[3] reported significantly greater grip strength in PRC patients compared with 4CA patients.
The lack of uniformity between results for grip strength following 4CA and PRC may
be explained by the findings of Nichols et al[5] which described alterations in muscle moment arms following both procedures. PRC
yielded a flexion bias and 4CA, a radial deviation bias. With the understanding that
grip strength may be optimized in wrist extension and ulnar deviation, the planar
changes in muscle moment arms may explain why reduced grip strength may follow both
procedures.
Following PRC, pathological changes to the radiocapitate joint may be due to nonanatomic
loading patterns and a mismatched radius of curvature between the capitate and lunate
fossa. The PRC review by Chim and Moran[11] determined that a high rate of radiographic radiocapitate arthrosis did not yield
clinically impactful findings at more than 10 years of follow-up. This finding is
consistent with Wagner et al[17] who reported 45% of moderate-to-severe radiocapitate arthrosis following PRC at
a mean follow-up of 13 years. Using four-dimensional scanning in PRC patients at a
mean follow-up of 7.3 years, Peymani et al[18] described increased radiocapitate contact area and capitate remodeling. This is
indicative of the adaptive response which contributes to favorable outcomes despite
a nonanatomic result of PRC. Although the current findings show comparable rates of
advanced radiocapitate pathology between younger and older adults following PRC, continued
monitoring in younger adults may be advised.
Prior reports have identified patient age as an important consideration for treatment
decisions involving 4CA and PRC. Wagner et al[6] provided one of the few reports for the performance of 4CA and PRC in younger adults.
Their series spanned a spectrum of disease severity and indications, with few exclusions.
At a mean follow-up of 11 years for the 4CA group and 18 years for the PRC group,
there were similar rates of radiographic arthrosis in both groups, and motion trended
toward superior for the PRC group. Further, the same group provided a narrative review
of 4CA and PRC in young patients which highlighted the lack of definitive data in
support of either of these procedures.[19] Traverso et al[20] reported high patient satisfaction and function at more than 10 years follow-up
and noted the durability of 4CA in younger adults as 33% of the series were aged 45
years or under at the time of the index procedure. Despite 27% of 4CA cases having
advanced radiolunate space narrowing, the authors reported a mean DASH of 7.8, revision
to wrist fusion of 6.7%, and zero cases of nonunion. The current findings indicate
an increased risk of revision in younger adults compared with older adults following
4CA.
Important considerations have been identified to guide surgeons when evaluating 4CA
and PRC in younger adults. The review by the Wagner group noted that clinical satisfaction
following 4CA may be predicated on bony union.[19] Thus, activities such as smoking which increases the risk of nonunion must be considered.[21] Additionally, job or lifestyle activities which require a greater range of motion
may indicate a preference for the motion preservation of PRC. However, motion discrepancies
between PRC and 4CA may not be as functionally evident in younger adults due to adaptive
capacity. It is reasonable to anticipate if not expect adaptations in adjacent joints
to yield improved function over time. Further, the concern for radiocapitate arthrosis
following PRC is certainly more warranted in younger adults. In totality, the surgeon
must evaluate patient specifics including age and have a complete understanding of
the mechanics involved in 4CA and PRC when indicating these procedures.
We acknowledge existent limitations, primarily those that are inherent to amalgamating
the work of others. Errors and biases from the included studies weaken the current
work. Further, when aggregating clinical outcomes, there is the potential for reporting
and interpretation errors. DASH and QuickDASH differ in the number of questions which
can impact the absolute value of the score. These metrices are often reported interchangeably
which can confound aggregate reporting. Additionally, there was heterogeneity in the
verbiage used to report radiocapitate narrowing. The included studies infrequently
identified the specific cases which required revision; thus, the current findings
for revision should be interpreted as incomplete. However, the noted trend of increased
revision in younger adults following 4CA is consistent with prior literature and supported
by a reasonable sample of cases. The current data were compiled for all indications
which may hinder a more focused conclusion for each procedure. Although the applied
inclusion criteria using individual case data reduced the available sample of literature,
this methodology allowed age stratification and yielded 50 or more cases in each age
group which is a robust sampling for these procedures.
Conclusion
In aggregate, clinical outcomes at short-to-midterms of follow-up are comparable between
4CA and PRC. However, stratification of cases into age groups displays trends that
may be clinically relevant. PRC in patients over 45 years demonstrated significantly
greater grip strength recovery compared with patients under 45 years. Further, there
is an increased risk of disability based on the DASH score when treating patients
under 45 years with 4CA. This indicates the need for setting expectations prior to
4CA in younger adults.
