Keywords
proximal interphalangeal joint - volar plate - hyperextension deformity - swan neck
deformity - late volar plate repair
Introduction
Dorsal dislocation of the proximal interphalangeal (PIP) joint is a relatively common
injury, especially in sports-related accidents. It can result from an isolated rupture
of the volar plate (VP) or, more frequently, from collateral ligament ruptures or
fractures at the anterior lip of the base of the middle phalanx.[1] Acute traumatic rupture due to VP hyperextension usually occurs in its distal insertion,
at the level of the base of the middle phalanx; less frequently, it happens in the
middle zone of the VP or at a proximal location, such as the attachment of the proximal
phalanx.[1] Correct treatment with splint and rehabilitation leads to healing in most patients.
Incorrect diagnosis or treatment can result in VP incompetence and repeated episodes
of dorsal dislocation due to hyperextensions, potentially leading to pain, clicks,
functional impotence, deformity, and stiffness in the medium and long terms. According
to some authors,[2]
[3] VP rupture at the level of its attachment at the base of the middle phalanx can
cause chronic deformity due to PIP joint hyperextension, the so-called swan-neck deformity,
and a rupture at the level of its attachment in the proximal phalanx causes a pseudo-boutonnière
deformity.
Mild incompetence, clinically manifested as minimal hyperextension, is well tolerated;
more severe incompetence can cause pain and functional impotence, as the lateral bands
of the extensor digitorum muscle slide over the head of the proximal phalanx for PIP
joint mobilization.[2] In the long term, this instability can result in joint degeneration, pain, and stiffness.[3]
[4]
Treatment aims at restoring VP competence and joint stability. In cases of minimal
instability and no clinical repercussions, the initial management is conservative.
Failure of the conservative measures, increased instability, or symptoms of pain and
functional impotence indicate the need for surgical treatment. This treatment depends
on the degree of joint degeneration (direct VP repair, arthroplasty, arthrodesis,
corrective osteotomy etc.) and the patient's requirements.
The authors herein present their experience treating chronic dorsal dislocations of
the PIP joint by VP repair.
Clinical Cases
The present is a retrospective review of five cases of VP incompetence clinically
manifested by repeated dorsal dislocations of the PIP joint. The patients had a mean
age of 35.8 years (range: 17 to 45 years), and the time elapsed from trauma to treatment
was o 5.26 years (range: 4 months to 14 years) ([Table 1]). The fifth finger was affected in four out of five cases; in the fifth case, the
second finger was affected. As for the cause, three patients reported sports-related
accidents, and two patients reported work accidents. One patient had a swan-neck deformity
with functional impotence for active flexion ([Figure 1]), while the remaining four patients presented hyperextension of the PIP joint with
preserved flexion ([Figure 2]). All patients reported several episodes of dorsal dislocations caused by efforts
or falls followed by self-reduction.
Fig. 1 Swan-neck deformity with -20° of PIP joint hyperextension and failure at active flexion.
Fig. 2 Passive PIP joint hyperextension of -60° with 8 years of evolution (case 3).
Table 1
|
Age (years)
|
Finger
|
Time
|
Preoperative ROM
|
Postopoperative ROM
|
Follow-up
|
Preoperative strength
|
Postoperative strength
|
Catalano et al.[2] classification
|
|
1
|
42
|
5th
|
4 months
|
-20°– + 5°
|
+30°– + 85°
|
7 months
|
33/48 (68.75%)
|
40/55
(72.72%)
|
Fair
|
|
2
|
34
|
5th
|
14 years
|
-52°– + 86°
|
+15°– + 91°
|
13 months
|
28/58 (48.27%)
|
52/55 (94.54%)
|
Good
|
|
3
|
41
|
5th
|
8 years
|
-60°– + 95°
|
+5°– + 85°
|
15 months
|
36/54 (66.66%)
|
50/56 (89.28%)
|
Excellent
|
|
4
|
45
|
2nd
|
29 months
|
-15°– + 85 °
|
0°– + 90°
|
18 months
|
50/62 (80.64%)
|
58/60 (96.66%)
|
Excellent
|
|
5
|
17
|
5th
|
19 months
|
-65°– + 100°
|
+5°– + 90°
|
27 months
|
24/42 (57.14%)
|
40/42 (94.23%)
|
Excellent
|
The patients in the present series had a history of dorsal dislocation of the PIP
joint, anteroposterior instability, functional impotence, pain, and absence of lateral
instability. In all cases, plain radiographs (on posteroanterior and lateral views)
were performed preoperatively to rule out acute fractures, malunions, or degenerative
changes; in addition, a magnetic resonance imaging (MRI) scan was requested to assess
VP injury.
A functional evaluation performed before and after the intervention measured the range
of motion (ROM) and grip strength of the joint with a Jamar (JLW Instruments, Chicago,
IL, US) dynamometer. The clinical outcomes were classified as excellent, good, acceptable,
and fair according to the Catalano et al.[2] criteria ([Table 2]), which are specific to assess hyperextension lesions at the PIP joint.
Table 2
|
Catalano et al.[2] classification
|
Hyperextension correction
|
Flexion contracture
|
Pain
|
Stability
|
|
Excellent
|
Complete
|
0° to 5°
|
No
|
Stable
|
|
Good
|
Complete
|
5 to 15°
|
No
|
Stable
|
|
Fair
|
Complete
|
> 15°
|
Yes
|
Partially unstable
|
|
Poor
|
No
|
−
|
Yes
|
Completely unstable
|
Surgical Technique
The surgical technique used was VP repair. The VP was exposed using a Bruner-type
volar approach and reconstructed after minimal debridement of the affected ends. Central
tears deemed repairable were treated directly with a 3/0 absorbable monofilament polydioxanone
(PDS, Johnson & Johnson, New Brunswick, NJ, US) suture ([Figure 3]). Distal attachment avulsions ([Figure 4]) were treated with a transosseous reattachment through tunnels at the base of the
middle phalanx. In both cases, the tension provided must not exceed 5° of joint flexion[3]
[4] to avoid a residual flexion contracture.
Fig. 3 Intraoperative image of a case of central VP rupture.
Fig. 4 (Left) Intraoperative image of a case of distal avulsion of the VP. (Right) Volar plate reattachment with transosseous PDS suture.
Mobilization began at the first postoperative visit, 3 to 4 days after surgery, aided
by dorsal splints that limited extension and enabled flexion ([Figure 5]). Initially, the extension was limited to -15°, and the patient was advised to seek
full active flexion. The extension limit was reduced progressively every week until
full extension, around the third or fourth weeks, when the splints were removed. At
this stage, the patients were capable of performing full flexion, so our attention
focused on avoiding a potential extension deficit due to flexion contracture with
the overnight use of static splints or digital dynamic extension splints to correct
it.
Fig. 5 Immediate rehabilitation with dynamic dorsal locking splint.
Results
The intraoperative findings showed central VP tear in two cases ([Figure 3]), and distal avulsion in three cases ([Figure 4]). The VP could be repaired or reattached in all cases, with correction of the hyperextension
and swan-neck deformity, and no recurrences during the follow-up. There were no major
complications during the postoperative and rehabilitation periods.
[Table 1] summarizes the clinical outcomes. The mean follow-up period for the 5 patients was
of 18 months (range: 7 to 27 months). In the preoperative clinical examination, the
mean passive hyperextension was of 42° (range: 15° to 65°). The mean correction of
hyperextension was of 39°. Hyperextension was corrected in all patients, and none
showed recurrence of the initial deformity. According to the Catalano et al.[2] criteria, which evaluate functional outcomes regarding the PIP joint, three outcomes
were excellent, one was good, and one was fair. Of the three excellent cases, two
patients eventually presented mean extension deficits of 5°, while the other patient
had no deficit. The patient with a good outcome presented a 15° deficit, and the one
with a fair outcome had a 30° deficit after surgery.
Grip strength improved 25.4% on average (range: 3.97% to 46.27%).
The patient with a fair outcome (case 1; [Figure 1]) presented to the clinic four months after surgery due to hyperextension resulting
in dorsal dislocation. After reduction and immobilization, the patient presented hyperextension
with stiffness and inability to perform flexion. An open reduction showed that the
cartilage was in good condition and VP reattachment was feasible; later, however,
the patient presented stiffness and a contracture at 30° of flexion. Three months
after surgery, due to failure of the conservative measures, an arthrolysis was suggested
to correct the extension deficit, but the patient refused it. The authors believe
that this fair outcome does not result from a lack of rehabilitation or patient collaboration,
but from a probable injury to the extensor apparatus.
The radiological examinations showed no signs of joint degeneration during the follow-up
until the last visit.
Except for the case with the fair outcome, the rate of patient satisfaction was very
high. All patients returned to work.
Discussion
Dorsal dislocation of the PIP joint is a relatively common injury, and, in most cases,
patients respond well to conservative treatment, with good functional outcomes. Hyperextension
of the PIP joint can produce different degrees of injury, both at the level of the
VP and of the collateral ligaments. Most VP injuries heal with no major repercussions.
Occasionally, the lack of diagnosis or inadequate treatment can result in chronic
instability in the sagittal plane with PIP hyperextension or swan-neck deformity.
Some patients may experience pain, functional impotence, instability manifested as
repeated dislocation episodes from forced passive hyperextensions, and even osteoarthritis
in the long term.[1],[2],[3],[4],[5],[6] These clinical manifestations indicate the need for surgical treatment to provide
stability and preserve joint function.
Some authors[5]
[6]
[7]
[8]
[9] postulate that the longer the time between injury and treatment, the lower the probability
of repair due to theoretical VP scarring, fibrosis, and retraction; they describe
different techniques for reconstruction, including flexor digitorum superficialis
(FDS) tenodesis and reconstruction with the use of tendon grafts, strips of the lateral
band of the extensor digitorum muscle, or collateral ligaments.
In contrast, other authors[2]
[3]
[4]
[5]
[6] have described VP repairs with advancement and reattachment 8 to 12 years after
the injury, with good functional outcomes. In our opinion, this second approach is
more logical because the VP, due to its cartilaginous histological features (meniscus-like
structure)[1],[10], suffers no retraction and keeps its structure regardless of the time since the
injury,[1]
[6] enabling a late repair. The intraoperative macroscopic appearance of the operated
VPs (chronic cases) from our series confirmed this fact, since there were no differences
compared to acute lesions; as such, their repair was possible, regardless of the time
since the injury. The histological features of the VP can account for this finding.[1]
[4]
[10] Some authors[1]
[2]
[4] also believe that its vascularization pattern plays a role because the distal portion
of the VP is vascularized from the proximal portion by branches of the transverse
artery of the proximal digital arch, which connects the two digital arteries at the
level of the head of the first phalanx.
Repair of the VP, either by an end-to-end suture for central ruptures or reattachment
for avulsions, restores joint stability, correcting the deformity. Polydioxanone,
a monofilament suture with a reabsorption time ranging from 180 to 210 days, is used
to maintain the tension of the long-term repair. In addition, thanks to its reabsorption
by hydrolysis, the PDS disappears, which avoids issues related to the persistence
of foreign material at the joint.
Other techniques with higher morbidity, such as FDS tenodesis or reconstruction with
tendon grafts, are technically more complex and present a higher risk of flexion contracture.
In the Adams[5] series of VP reconstructions using a palmar minor tendon graft, 1 of 3 cases developed
a flexion contracture of 25°. Littler[7] described the FDS tenodesis technique in 1959, and Catalano et al.[2] made it popular in 2003. Catalano et al.[2] presented 12 patients, with a mean ROM ranging from 12° to 100° after surgery, and
2 cases of flexion contractures of 60° and 90° respectively.[2] On the other hand, FDS tenodesis can alter the flexor mechanism and increase the
risk of tendon adhesions.[5] Swanstrom et al.[6] describe an extra-articular modification of the classic FDS tenodesis using an intraosseous
anchor to fix the ulnar hemitendon of the FDS. This technique was performed in 5 patients
with a mean follow-up time of 5.5 years, resulting in a ROM ranging from -1 to 96°,
with no reports of flexion contracture; in contrast, other tenodesis techniques with
an articular approach resulted in flexion contracture ranging from 5° to 90°.[2]
[5]
Foucher et al.[8] and Zancolli and Zancolli[9] described extra-articular techniques for the correction of hyperextension deformity.
These techniques involved the transfer of strips from the lateral bands of the extensor
digitorum muscle and had variable outcomes, with extension deficits ranging from 10°
to 30° depending on the method.
The VP can be reattached to the middle phalanx using transosseous sutures,[4] pull-out techniques,[3] or any bone-anchoring system; no method was proven to be clearly superior to the
others.[4] Kaneshiro et al.[3] presented 7 cases of VP reattachment using a transosseous pull-out suture with a
mean time from injury to surgery of 21 months, and a postoperative follow-up time
of 28 months. The average ROM was of 80.5°, with a mean flexion contracture of 9°.[3] Melone et al.[4] presented 25 cases of VP reattachment using a transosseous absorbable (PDS) suture
with a mean time from injury to surgery of 8.2 years, and a postoperative follow-up
time of 8 years; the mean ROM ranged from 6° to 92°, with flexion contracture ranging
from 5° to 15°.
Consistent with other authors,[1]
[3]
[4]
[5] we believe that, despite a long time between injury and repair, late reattachment
of the VP is possible and enables a more anatomical reconstruction. It avoids the
morbidity of sacrificing healthy structures, such as tendons or ligaments, and its
complications, such as loss of strength, instability, adhesions, and/or stiffness,
including flexion contractures.[3]
[4]
In cases of compensatory swan-neck deformity due to VP incompetence, the treatment
plan must include VP reattachment with the technique herein described, which corrected
the swan-neck deformity in all treated patients. Had this not been enough, we would
have considered personalized splints, Littler-type tenodesis, or reconstruction of
the spiral oblique retinaculum ligament as required by each case.[4]
[7]
[9]
Tenodesis with the FDS may be a good alternative in patients with an irreparable VP.[2]
[3]
[4] If the radiological study reveals degenerative changes, the therapeutic options
include arthroplasty with prosthesis, arthrodesis, or transfer of a vascularized PIP
joint from a toe.
Conclusion
Repair is a reliable technique to treat VP incompetency and repeated dorsal dislocations
of the PIP joint. It enables the restoration of joint stability and deformity correction
with minimal morbidity. Thus, it should be considered an excellent option to treat
PIP instability, regardless of the time elapsed since the injury.
