Keywords
bowstringing - flexor tendon - pulley reconstruction - pulley rupture - rock climbing
Introduction
The finger flexor pulleys act like a fibrous envelop preventing flexor tendons divergence
from their anatomic location. They allow the conversion of pulling action into an
angular motion that causes the finger joints to bend.[1] Pulley system injuries are overall rare; however, these lesions can be often observed
in rock climbers. The reason for such peculiar finding is due to the position of the
hand during the activity, called “crimp grip” with proximal interphalangeal joint
(PIPJ) flexed to 90 to 100 degrees and distal interphalangeal joint (DIPJ) hyper-extended.
In this condition, flexor tendons apply very intense bowstringing forces on the pulleys.
The repetitive loading on pulleys during rock climbing activity may lead to acute
damages or to overuse syndrome.[2]
Depending on the characteristics of the lesion, Schöffl et al[3] proposed a grading system to guide the therapeutic choice, dividing pulley injuries
into four grades. He distinguished grade 1 with pulley strain, grade 2 with a complete
rupture of A4 or partial rupture of A2, grade 3 with complete rupture A2 or A3, grade
4 with multiple ruptures (as A2/A3, A2/A3/A4) or single rupture (as A2 or A3) combined
with lumbricalis muscle or collateral ligament trauma. Then, the author proposed conservative
therapy for grade 1 to 3, and surgical treatment for grade 4 pulley injuries.[3]
During the last two decades, scientific literature on closed finger flexor pulley
injuries increased. Nonetheless, until now, there are few published studies evaluating
management strategies and treatment outcomes for this condition. The aim of this systematic
review was then to gather current indications and treatment options for flexor tendon
pulley injuries, and to evaluate clinical results of conservative and surgical repair
reported in the literature.
Materials and Methods
Eligibility Criteria
This systematic review was conducted according to Preferred Reporting Items for Systematic
reviews and Meta-Analyses (PRISMA) guidelines.[4] We evaluated current evidence of closed finger pulley rupture treatments and outcomes.
For the systematic review, we used the following inclusion criteria: articles published
in English, French and Italian languages, studies published within the past 20 years,
full text of the articles should be available, human studies only. We excluded from
our research studies less than five participants, editorials, technical notes, preclinical
studies, and review articles.
Search Strategy and Information Sources
The research was limited from January 2000 to March 2022. Our literature research
of PubMed and Scopus database was performed using the following MeSH keywords: ([pulley
rupture] OR [finger pulley lesion]) AND ([injur*] OR [ruptur*] OR [damage] OR [trauma*]).
Initial screening results identified 461 studies, among which 172 were included after
including additional records identified through other sources and excluding repeated
studies.
Study Selection
Following the research, two reviewers (FB and AL) independently reviewed all articles
to evaluate their contribution to this study using the aforementioned eligibility
criteria. The title and abstract of all articles were reviewed. Furthermore, full
text of each selected article was retrieved. After reviewing each study according
to the inclusion and exclusion criteria, four clinical studies that analyzed closed
finger pulley rupture treatments and outcomes were included in the analysis. The corresponding
PRISMA flowchart diagram is shown in [Fig. 1].
Fig. 1 Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) flowchart
diagram of the systematic review.
Data Items and Extraction
Extracted data were recorded in a Microsoft Excel spreadsheet (version 2016; Microsoft,
Redmond, Washington, United States). A data collection tool was created by the authors
extracting the following data: author and publication year, study design, number of
groups, groups, sample size patients, follow-up, lost to follow-up, sample size patients
treated, trauma mechanism, diagnosis, involved fingers, involved pulleys, lesion grade,
treatment, surgical technique, outcomes, complications, sample size sex, sample size
mean age ([Tables 1] and [2]).
Table 1
Main demographic characteristics of patients collected from comprehensive research
of literature
|
Author and publication year
|
Groups
|
Sample size patients
|
Sample size sex
|
Sample size mean age, yo
|
|
M, n
|
F, n
|
|
Schöffl et al (2003)[3]
|
A
|
115
|
43
|
5
|
Not specified
|
|
B
|
7
|
67
|
7
|
|
|
Schöffl and Jüngert (2006)[7]
|
A
|
5
|
3
|
3
|
44.6
|
|
B
|
1
|
|
|
|
|
Arora et al (2007)[10]
|
A
|
13
|
11
|
2
|
41
|
|
B
|
10
|
9
|
1
|
38
|
|
Bouyer et al (2016)[11]
|
A
|
30
|
24
|
6
|
Not specified
|
|
B
|
8
|
7
|
1
|
|
Abbreviations: F, female; M, male; n, number (of patients); yo, years old.
Table 2
Summary results of the included studies
|
Author and publication year
|
Trauma mechanism
|
Diagnosis
|
Groups
|
Sample size patients treated
|
Involved fingers
|
Involved pulleys
|
Lesion grade
|
Treatment
|
Surgical technique
|
Outcomes
|
Complications
|
|
Schöffl et al (2003)[3]
|
Rock climbing
|
Clinical, US, MRI
|
A
|
80
|
III (n = 47)
IV (n = 73)
V (n = 2)
|
A2 (n = 88)
A3 (n = 13)
A4 (n = 31)
|
1, 2, 3
|
Conservative
|
|
Not specified
|
Not specified
|
Not specified
|
Not specified
|
Not specified
|
Not specified
|
Not specified
|
7
|
|
B
|
7
|
4
|
Surgical
|
The “loop-and-a-half” technique of Widstrom
|
1
|
3
|
2
|
1
|
0
|
|
Schöffl and Jüngert (2006)[7]
|
Non ̶ rock climbing
|
Clinical, US, MRI
|
A
|
5
|
III (n = 3)
IV (n = 3)
|
A2 (n = 6)
|
1, 3
|
Conservative
|
|
5
|
0
|
0
|
0
|
Not specified
|
Not specified
|
Not specified
|
Not specified
|
Not specified
|
Not specified
|
2
|
|
B
|
1
|
3
|
Surgical
|
Lister's Extensor Retinaculum Technique
|
1
|
0
|
0
|
0
|
|
Arora et al (2007)[10]
|
Rock climbing and non ̶ rock climbing
|
Clinical, US, MRI
|
A
|
13
|
III (n = 17)
IV (n = 6)
|
A2 (n = 23)
A3 (n = 9)
|
Complete closed flexor tendon pulleys injuries (grade nonspecified)
|
Surgical
|
Lister's Extensor Retinaculum Technique
|
10
|
2
|
1
|
0
|
48/50
|
8/8
|
Not specified
|
Not specified
|
Not specified
|
Not specified
|
0
|
|
B
|
10
|
Surgical
|
Kleinert/Weilby Technique (Shoelace Weave)
|
7
|
2
|
1
|
0
|
48/49
|
7/7
|
0
|
|
Bouyer et al (2016)[11]
|
Rock climbing
|
Clinical, US, MRI, CT
|
A
|
30
|
II (n = 1)
III (n = 13)
IV (n = 24)
|
A2 (n = 33)
A3 (n = 3)
A4 (n = 2)
|
Complete closed flexor tendon pulleys injuries (grade nonspecified)
|
Surgical
|
Lister's Extensor Retinaculum Technique
|
38
|
0
|
0
|
0
|
Not specified
|
Not specified
|
70%; 16/23
|
21%
|
97% (SD: 4)
|
Not specified
|
15
|
|
B
|
8
|
25%; 2/8
|
50%
|
93% (SD: 4)
|
Abbreviations: %, percentage; CT, computed tomography; Inj., injury; kg, kilogram;
MRI, magnetic resonance imaging; n, number (of patients); not inj., not injury; TAM, total active motion; US, ultrasonography.
Evaluation of Methodological Quality
The Oxford Center for Evidence-Based Medicine 2011 level of evidence (LoE)[5] was used by the authors to assess the strength of results in research studies. Articles
were graded from levels 1 to 5. The methodological quality of the articles was evaluated
independently by two authors (FB and AL) through the methodological index for nonrandomized
studies (MINORS) score.[6] The best methodological quality of a comparative article is set at 24 points, while
case series can reach a maximum of 16 points. A third author (SA) resolved any cases
of disagreement. All authors participated equally in the study design, manuscript
preparation, and final review.
Results
In our systematic review, we identified four studies that enrolled a total of 189
patients, of whom 164 male and 25 females (male/female ratio, 0.87). In one clinical
study[3] the authors lost 35 patients during follow-up. Then, 154 patients with a total amount
of 208 pulleys damaged (A2 n = 150, A3 n = 25, A4 n = 33) were finally examined. Except for the thumb, all fingers were involved (index
finger n = 1, middle finger n = 80, ring finger n = 106, little finger = 2). Closed finger pulleys injury occurred in rock climbers
(n = 142) and in nonrock climbers' patients (n = 12). Depending on the type of flexor pulley injury, graded with Schöffl classification,[3] 69 patients underwent a surgical procedure, whereas 85 patients were treated conservatively.
The main demographic characteristics of patients collected from comprehensive research
of literature are listed in [Table 1].
In 2003, Schöffl et al studied 122 rock climbing patients with pulleys system injuries.[3] Only 87 completed the follow-up, of whom 80 were treated conservatively and seven
surgically with a “loop and a half” technique of pulley reconstruction. No data were
reported about mean age, surgical timing, and mean follow-up. According to Schöffl
criteria, grade 1 to 3 injuries received conservative therapy, and grade 4 injuries
received surgical repair. Outcomes were analyzed with a nonclinical score by assessing
the level of return to sports activity according to the Union Internationale des Associations
d'Alpinisme (UIAA).[3] All patients treated conservatively returned to their previous level of sports activity,
except for seven who needed more time to return to full recovery because of persistent
pain due to tenovaginitis. Surgically treated patients presented “very good” results
in one case, “good” in three cases, “sufficient” in two cases, and “poor” in one according
to the return to UIAA sports activity level. All the patients required finger protection
as part of the treatment.
Three years after their previous study, Schöffl et al published another study evaluating
six nonclimbing patients with flexor pulley injuries.[7] All patients were treated conservatively except one, who underwent pulley reconstruction
using a retinaculum extensor graft. The mean age of patients was 44.6 years, and the
mean follow-up time was 6 weeks. Clinical outcomes were “excellent” for all the patients
according to Buck-Gramcko score.[8]
[9] A 5 degrees PIPJ extension deficit was found in two cases.
In 2007, Arora et al conducted a study on 23 patients with complete closed flexor
tendon pulleys injuries who underwent surgical treatment.[10] In 13 cases, pulley reconstruction was performed using a retinaculum extensor graft
(group A), and in 10 cases using a free tendon graft of palmaris longus (group B).
The average age in group A was 41 years, and 38 years in group B. In group A, the
interval between injury and surgical procedure was 9 weeks with a follow-up of 58
months, whereas in group B, the interval time was 7 weeks and the average follow-up
was 57 months. The authors used Buck-Gramcko score to evaluate the two surgical procedure
outcomes. In group A, ten patients achieved “excellent” results, two “good” results,
one “fair” result. In group B, seven patients had “excellent” results, two “good”
results, and one “fair” result. Pitch and grip strength were also analyzed noting
very good outcomes in both groups. No complications were found in group A and B.
In 2016, Bouyer et al published a work involving 38 patients with complete pulley
injuries evaluated on 85 months follow-up.[11] The mean age of the patients included in the series was not reported. Patients enrolled
in the study were divided into two groups based on the return to previous climbing
activity. Those who returned to their prior sport level (n = 30) showed less than 2 mm US E-space (defined as the residual bowstringing, corresponding
to the distance from phalanx to the deep face of the tendon of the finger flexors)
in 70% of cases, permanent pain in 20%, a PIPJ extension deficit greater than 10 degrees
in 19%, a grip strength of 102%, a tip pinch strength of 97%, and a total active motion
(TAM) score of 97%.
Patients who were unable to return to their previous climbing level (n = 8) had significantly worse results showing less than 2 mm US E-space in 25% of
cases, persistent pain after the treatment in 50%, a PIPJ extension deficit greater
than 10 degrees in 25%, a grip strength of 94%, a tip pinch strength of 82%, and a
TAM of 93%. In this group, the interval time between injury and surgical treatment
averaged 6.8 months, being 2.4 months longer than in the group with a complete return
to sport level.
All patients had excellent results on the Buck-Gramcko score regardless of the return
to sports activity. The following complications were noted: failed procedures (n = 2), pulp paraesthesia on involved finger (n = 2), asymptomatic flexor nodule (n = 1), extensor bowstringing on the harvested wrist (n = 6/30, n = 4/8).
A comprehensive evaluation of each article reviewed is available in [Table 2].
Discussion
Flexor pulley injuries are a clinical entity of great interest in hand surgery, and
most of these injuries occurred during rock climbing. This activity gained popularity
over the last years, being recently included in Olympic sport disciplines.[12]
[13] Then, at present, a large number of athletes is potentially exposed to these otherwise
uncommon injuries.
Flexor tendon pulleys represent 33% of all injuries observed during climbing, and
in competitive athletes, there is an estimated 19 to 26% incidence of pulley ruptures.[12]
[13] The most commonly injured sites are the middle and the ring fingers,[14] with the A2 pulley being the most frequently damaged pulley followed by A4.[15]
[16] Patients describe the moment of the trauma as an acute pain onset, or a “tearing”
sensation, occasionally accompanied by a loud “pop” and followed by impairment in
flexion movements and decreased finger dexterity.[1]
[2]
Bowstringing, which is a very typical injury sign, is not always observed. It may
lead to incomplete shortening of the tendon during muscle contraction, resulting in
a loss of power in pinching and grasping.[2] These findings are not specific, therefore imaging with the radiographic exam, ultrasound
(US), and magnetic resonance imaging (MRI) is usually needed to confirm diagnostic
suspicion.[16]
[17]
The data extracted in this systematic review of the literature showed that the indication
for conservative versus surgical treatment is still debated.
Schöffl et al[3]
[7] according to his classification treated conservatively grade 1 to 3 pulley injuries,
reserving surgery for grade 4. The only exception was a patient with a grade 3 injury
who was treated surgically suspecting an underlying flexor tendon injury. The surgical
technique adopted by Schöffl et al in 2003 was Widstrom's loop-and-a-half technique:
a free palmaris longus graft wrapped around the phalanx and passed through a surgically
opened operculum in the thickness of the graft, then each end is sutured on both sides.
The 2006 surgical procedure was the Lister's Extensor Retinaculum Technique. In this
technique, the surgeon harvests an extensor retinaculum graft, which is wrapped around
the phalanx and then sutured to itself.[3]
[7]
[14]
[16]
Arora et al[10] preferred conservative treatment for partial pulley ruptures. In 23 patients surgically
treated in his study, 14 showed A2 pulley rupture (Schöffl grade 3), and nine showed
combined A2 and A3 ruptures (Schöffl grade 4). Two types of surgical procedures were
used. The first is the Kleinert/Weilby Technique (Shoelace Weave), in which the surgeon
harvests an flexor digitorum superficialis (FDS) graft, which is then passed like
a shoelace through the holes created in the remaining pulley stumps. The second technique
was the Lister's Extensor Retinaculum Technique described above.[10]
[14]
[16]
Finally, Bouyer et al[11] reported that in their series including 38 cases, surgical treatment was performed
in two patients with grade 2, thirty patients with grade 3, and six patients with
grade 4 according to Schöffl classification.[3] Bouyer et al also adopted the Lister's Extensor Retinaculum Technique as the surgical
procedure they used.[11]
[16]
Overall, surgical treatment was never indicated in grade 1 (pulley strain), rarely
indicated in grade 2 (partial pulley rupture of A2 or A3, complete rupture of A4),
and almost always performed in grade 3 (complete rupture of A2 or A3), and grade 4
(combined ruptures A2-A3 or A2-A3-A4).
The grade 3 flexor pulley injury appeared then as a gray zone area in which both conservative
and surgical treatment may give favorable results and return to the sports activity
level in rock climbing athletes.
The physical therapy protocol prescribed by Schöffl et al[3] is related to the grade of injury. In grade 1, a functional therapy of 2 to 4 weeks
is recommended, without any prescribed immobilization, but protection of the pulley
by taping is recommended. In grade 2, immobilization for 10 days is recommended, followed
by cautious functional therapy for 2 to 4 weeks, and tape to protect the damaged pulley.
Immobilization is extended to 14 days in grade 3 and grade 4, which are more frequently
surgically treated, with functional therapy for up to 4 weeks and protection of the
damaged pulley with a thermoplastic ring. Various scores could evaluate the results
after treatment, whether conservative or surgical.
Regarding the assessment of clinical outcomes, the Buck-Gramcko score was the most
frequently used in the studies included in this systematic review.[7]
[10]
[11] The total number of patients evaluated with the Buck-Gramcko and treated conservatively
was five, and all reported an “excellent” outcome. The total number of patients treated
surgically evaluated with the Buck-Gramcko score was 62, of whom 56 reported an “excellent”
result, four “good,” two “fair,” and no “poor.”
Schöffl et al did not evaluate clinical outcomes with Buck-Gramcko score in their
article published in 2003.[3] Nonetheless, they reported largely favorable results for conservative treatment
with the UIAA score. Similarly, the outcome of the surgically treated patients evaluated
with the same score was “excellent” in one case, “good” in three, “fair” in two, and
“poor” in one.
Functional results were satisfactory in both conservative and surgical treatment,
considering the overall outcomes of the reviewed articles. Moreover, surgical results
were more positive than conservative results in grades 3 and 4 regardless of the specific
technique used for finger pulley reconstruction. For this reason, conservative treatment
is a reasonable choice for patients with low-grade lesions. At the same time, surgical
treatment should be considered in the first instance, when patients are affected by
more severe acute injuries, independently of the technique used, as studies show that
in high-grade lesion surgical treatment is more effective than conservative treatment
in functional recovery and return to sport.[18]
[19]
[20]
Our systematic review showed some limitations that must be mentioned. First, it must
be said that the number of papers reviewed was small and that the studies included
in the analysis were all retrospective case series. The age of the patients, the time
of follow-up, and the surgical timing were not reported in all the studies. Furthermore,
Arora et al[10] and Bouyer et al[11] in their studies mentioned complete closed flexor tendon pulleys injuries not specifying
the injury grade. The outcome assessment was heterogeneous because the same score
was not used in all the studies. A significant loss of patients during follow-up (35
patients) was observed in the first study published by Schöffl et al, and the outcomes
were reported with a nonclinical score difficult to interpret.[3] The choice of surgical techniques was also performed according to the author's preference,
and no gold standard procedure could be suggested.
Conclusion
Closed flexor tendon pulley injuries require careful examination and a high index
of suspicion, particularly in patients who are involved in the sports activity. Radiographic
exam, US, and MRI are suggested to confirm the diagnosis and detect the grade of soft
tissue injury. On this basis, the most appropriate treatment can be selected, and
in most cases, positive clinical results can be achieved with either conservative
or surgical therapy.
