Keywords wrist pain - extensor carpi ulnaris - tenosynovitis - wrist ulnar-sided pain - arthroscopy
portals - wrist arthroscopy complication
Introduction
Pain on the ulnar side of the wrist is a common symptom of several diseases such as
tendinitis of the extensor carpi ulnaris (ECU) and flexor carpi ulnaris (FCU), arthrosis
between the pisiform and the triquetrum, lesion of the triangular fibrocartilage complex
(TFCC), ulnocarpal impingement syndrome, instability of the distal radioulnar joint
(DRUJ), and lesion of the lunotriquetral ligament, among others. The complexity of
the structures and the proximity of the anatomical sites make the diagnosis difficult,
even when high-definition imaging exams are available.[1 ]
[2 ]
[3 ]
Stenosing tenosynovitis of the sixth extensor compartment of the wrist (SECW) was
first described in 1927, comprising a disease that is like the first compartment lesion
as described by De Quervain. It is a tendon inflammatory process that may be caused
by rheumatic diseases, bone friction after ulnar styloid process fracture, impact
by a prominent styloid process, distal ulnar instability, or overload generated by
repetitive activities in pronation and ulnar deviation of the wrist. Thus, the ECU
tendon sheath becomes inflamed, generating tendon swelling and compression within
the compartment.[4 ]
[5 ]
[6 ]
[7 ]
[8 ] Initial treatment is performed with conservative measures, being effective in most
patients. However, unresponsive lesions or those with chronic involvement may require
surgical treatment, and open tenosynovectomy is the standard treatment, with the release
of the compartment and resection of inflammatory tissue from both the tendon and adjacent
structures.
Tenoscopy can be used to perform an endoscopic exploration of the inside aspect of
the tendon sheath, and this procedure has been described for the treatment of ankle,
elbow, shoulder, wrist, and hand diseases.[9 ]
[10 ]
[11 ]
[12 ]
We report a series of eight wrists operated with ECU tenoscopy in six patients with
chronic tenosynovitis of the ECU, along with description details of the technique
and results.
Methods
Retrospectively, from January 2018 to December 2021, all patients treated with SECW
tenoscopy with tenosynovitis of the ECU refractory to conservative treatment for at
least four months were assessed and included in the study. We have included in the
series eight tenoscopies in six patients.
Patients who presented instability of the ECU tendon within the sixth compartment,
patients who underwent associated bone procedures, and patients who presented degenerative
changes of the DRUJ associated with tenosynovitis were excluded. For this purpose,
all patients were submitted to radiographs and magnetic resonance imaging before surgery.
Anatomy and Biomechanics
Omokawa et al.[13 ] divided the ECU tendon into three zones. Zone I is located at the ulnar groove;
zone Il at the ulnar styloid; and zone III at the triquetrum. The anatomical differences
of the sheaths and stabilizing structures in each zone are considerable and must be
taken into consideration when treating diseases and synovitis of the ECU.
In Zone I, the tendon of the ECU runs onto a groove at the distal ulna and is stabilized
by the extensor retinaculum that attaches to the radius, ulna, and to the carpal bones.
In its deep portion, the ECU tendon has a sheath, which is a connective tissue structure
attached to the retinaculum and the floor of the sixth compartment.
A little more distal, leaving the ulnar bone groove, at zone II, the sheath is more
tense and connects the ECU tendon to the ulnar styloid process and to the dorsal radioulnar
ligament. There is also at this point a structure of parallel-oriented collagen fibers
that connect the extensor retinaculum to the ulnar styloid called “linea jugata ,” which is important for tendon stabilization.
On the other hand, zone III, the most distal part of the ECU, in its path before inserting
onto the base of the fifth metacarpal, is devoid of a deep sheath. However, there
are extensions of the retinaculum in this area called retinacular septa, which can
be ulnar and radial and are variably present in the population, keeping the ECU tendon
near the triquetrum in a relatively stable position.
Another important anatomical aspect is the presence of accessory extensions of the
ECU tendon that insert into different parts of the fifth metacarpal base and other
dorsal structures. These anatomical variations may be an additional cause of pain
seen in ECU tendinopathies, in addition to limiting wrist and little finger motion.[14 ]
[15 ]
Bone groove anatomy at the distal ulna is also variable.[16 ] Patients with shallow sulci have been associated with a higher risk of instability
and, consequently, ECU tendinopathy. In such cases, when this change is confirmed,
sulcus deepening may be a step in the treatment.[17 ]
Flexion and extension of the wrist and forearm rotation also influence the stability
of the ECU tendon. Ghatan et al.[18 ] have shown the importance of the deep sheath of the ECU for stability. They have
also pointed out that forearm supination and wrist flexion tend to generate a force
that displaces the ECU tendon out of its groove. On the other hand, forced pronation,
especially with wrist extension, squeezes the distal part of the subsheath, thus increasing
pain in patients with an inflammatory process in the ECU and SECW.
Surgical Technique
Clinical aspects ([Fig. 1 ]) and radiological findings ([Fig. 2 ]) are revised before the procedure starts. With the patient supine and a pneumatic
tourniquet applied to the proximal arm, the upper limb is positioned on the table
for hand surgery. As in all wrist arthroscopies, the procedure is performed with the
aid of a wrist traction tower, along with surgical finger traps ([Fig. 3 ]).
Fig. 1 A 38-year-old patient with chronic tenosynovitis of the sixth extensor compartment
of the wrist (red arrow) due to rheumatoid arthritis (A , B , and C ).
Fig. 2 MR images demonstrate tenosynovitis of the ECU (red arrow) with little intra-articular
involvement. Transverse (A and B ), coronal (C ), and sagittal (D ) views.
Fig. 3 Initial treatment with classic arthroscopy technique (A ). Tenoscopy proceeds with the scope in the 6R portal. Treatment is performed with
the scope inserted through the 6R portal and instrumentation through the proximal
portal of the specific ECU (proximal ECU) portal (B ). Complete resolution of the increased volume due to synovitis (C ).
The procedure begins with an inspection of the radiocarpal joint (RCJ) using portals
¾ and 6R to rule out other intra-articular diseases that may cause pain on the ulnar
side of the wrist, such as ruptures of the TFCC, of the lunotriquetral ligament and
ulnocarpal impingement. Then, the midcarpal joint (MCJ) is evaluated for the same
reason.
Next, using the shaver through the 6R portal, capsule resection is performed ulnar
to the 6U portal along with the deep portion of the ECU sheath, allowing ECU tendon
visualization and subsequent optics entry within the sixth extensor compartment ([Fig. 4 ]). Then, with the optics in the 6R portal, a proximal ECU portal is created, located
two centimeters proximal to the distal end of the ulna. We can use a needle to define
the correct position of this portal, looking with the scope inside the compartment,
thus using the outside-in technique. In this location, by using the 6R and proximal
ECU portals, we were able to directly visualize the inside of the compartment, preserving
the extensor retinaculum that is fixed on the most distal part of the ulna, and the
ECU tendon. Moreover, due to portal placement, the sensory branches of the ulnar nerve
are protected, as they are more distally and ulnarly located to the portal of the
ECU. In case of a very extensive synovitis, a second specific portal to the ECU may
also be created at two centimeters distally to the distal ulna, the so-called distal
ECU portal.
Fig. 4 Radiocarpal joint view, with the scope in portal ¾ and the shaver in portal 6R, between
the tendons of the ECU and EDQ (A ). View inside of the sixth extensor compartment, with the scope in portal 6U. There
is extensive synovitis with inflammatory pannus throughout the region (B ). Distal view of the extensor compartment after tenosynovectomy (C ). Proximal view of the compartment after tenosynovectomy (D ). # Extensor digiti quinti *Extensor carpi Ulnaris @ sinovite.
After the portals are created, the synovectomy of the ECU tendon and the internal
sheath of the sixth compartment is performed both proximally and distally to the joint
([Fig. 5 ]).
Fig. 5 Schematic drawing of the technique for ECU synovectomy. The scope is in the portal
¾ showing the deep portion of the sheath of the ECU during a shaving procedure of
the ECU synovitis with the shaver in the portal 6R (A ). Subsequently, with the scope in the 6R portal, it is possible to visualize the
inner part of the sixth compartment and the proximal and distal ECU sheath. The shaver
can then be positioned in ECU-specific portals (proximal or distal) for synovectomy
(B ).
Before portal closure, the tourniquet is released to check the integrity of the vascular
bundles. The incisions are stitched with 5–0 monofilament nylon sutures. Note the
postoperative appearance demonstrating complete resolution of the edema ([Fig. 6 ]). Sterile dressings with sterile gauze and bandages are applied and a short-arm
plaster slab is used, immobilizing the wrist for a short period of time until the
dressing is changed, which occurs three to seven days after surgery. After the immobilization
period, the operated wrist is left with free motion, and patients are instructed to
use a removable orthosis on the dependence of their pain.
Fig. 6 Twelve days postoperatively from arthroscopy and tenoscopy showing access portals
¾, 6R, and proximal ECU. There is a complete disappearance of the increased volume
caused by synovitis of the ECU, more evident when compared with the contralateral
side that was operated on a few months later.
Patients were followed on an outpatient basis, with weekly consultations for a month
and then with quarterly assessments. In general, patients are not submitted to a specific
rehabilitation protocol with a hand therapist. They are oriented to perform stretching
exercises and gain mobility and strength at home.
Case Series
We have treated eight wrists of six patients in the last four years using the tenoscopy
technique as described above. Most patients had a previous diagnosis of rheumatoid
arthritis or another chronic rheumatic disease, were treated with disease-modifying
antirheumatic drugs, and with no previous invasive procedures performed on the wrist.
Clinical and epidemiological data of the patients are summarized in [Table 1 ]. There were five female patients and one male patient. The mean age on the day of
the procedure was 54.6 years, ranging from 38 to 68 years. Of the eight operated wrists,
six were on the right side and two on the left side; two patients underwent bilateral
procedures at different times (wrists ½ and ¾). Four patients had rheumatoid arthritis,
one patient had lupus and one had hypothyroidism. The mean time of conservative treatment
for wrist tenosynovitis prior to surgery was 5.1 months, ranging from 4 to 6 months.
The mean postoperative follow-up was 17.9 months, ranging from 12 to 30 months.
Table 1
Patient (wrist[* ])
Age
Gender
Dominance
Affected side
Underlying pathology
Time of conservative Treatment (months)
Time of follow up (months)
Pain
VAS
(pre op)
Pain VAS
(post op)
Associated orthopedic conditions
1
67
F
R
R
RA
4
30
5
1
RL arthritis
2
67
F
R
L
RA
5
12
5
1
RL arthritis
3
38
F
R
R
RA
5
20
9
1
–
4
38
F
R
L
RA
6
18
9
1
–
5
43
F
R
R
RA
4
18
6
0
–
6
55
F
R
R
–
6
12
7
2
–
7
60
F
R
R
RA
5
15
8
0
–
8
68
F
R
R
HT
6
18
8
2
–
To analyze pain, a visual analog scale was used on a ruler, ranging from zero (no
pain) to 10 (maximum pain already experienced). Before surgery, patients reported
an average of 7, ranging from 5 to 9. Postoperatively, the average pain was 1, ranging
from zero to two. Thus, among the eight wrists operated, two remained with mild pain
(score two on the scale) and have controlled pain symptoms with medication.
There were no cases of infection, hypertrophic scarring, complex regional pain syndrome,
or complications requiring a second procedure. There was also no recurrence of the
lesion during follow-up. Regarding motion, all patients displayed complete recovery
as compared with the motion before the procedure.
Regarding the treatment outcome reported by the six patients, we asked them to choose
among the following options: very satisfied, satisfied, not very satisfied, and not
satisfied. Of the total number of patients, five considered themselves very satisfied
and one regarded to be satisfied.
Discussion
Ulnar-sided wrist pain is a common feature of many disorders, such as ECU and FCU
tendinitis, arthrosis and DRUJ instability, TFCC injuries, ulnocarpal impingement
syndrome, and lunotriquetral ligament injury, among others. Structure complexity and
their proximity make diagnosis difficult, even when state-of-the-art imaging tests
are available.[19 ]
Moreover, there may be a disease association. Kakar and Garcia-Elias[20 ] defined an algorithm named “Four-Leaf Clover” to diagnose and treat ulnar wrist
lesions, showing that pathology at this region may be secondary to bone deformity,
ECU instability, chondral defects, and TFCC lesions, and the association among them
is common.
Another less frequent problem that may also create pain on the ulnar side of the wrist
is ECU tenosynovitis. There has been growing interest in identifying, understanding,
and treating this ECU pathology, which can often be resolved through minimally invasive
procedures and surgeries that impose less damage upon healthy structures.
De Torres et al. described a safe and feasible way to visualize the ECU tendon and
the inside aspect of SECW through ECU-specific arthroscopic portals, proposing that
during a wrist arthroscopy that aims to investigate ulnar-sided pain, an important
step to take is the assessment of ECU, as well as the deep sheath and the extensor
retinaculum of the sixth compartment.[21 ]
As our series have shown, most patients with tenosynovitis of the ECU carry some rheumatic
pathology, such as rheumatoid arthritis and lupus. In these patients, inflammatory
pannus formation occurs within the SECW, which can compress and invade the ECU tendon
and may even evolve to its rupture if left untreated.[9 ]
Other diseases such as gout, mycobacterial infections, and amyloid deposition diseases
may also manifest as tenosynovitis of the sixth compartment.[9 ] Another possible cause for the appearance of an inflammatory process is the stenosing
tenosynovitis of the ECU, generated by the thickening of the deep sheath of the sixth
compartment, a collagen-rich structure that surrounds the entire tendon connecting
to the ulnar sulcus, the dorsal radioulnar ligament, and the triquetrum and pisiform
bones.
Treatment of patients with tenosynovitis of the ECU begins with conservative measures,
with the use of drugs, orthotics, and ice. Chronic lesions that have not responded
to conservative treatment may require surgical treatment. Synovectomy is the goal
of the procedure, and the open technique is still the standard of care, with a wide
release of the compartment and resection of inflammatory tissue, both from the ECU
tendon and the adjacent structures located inside the sixth compartment.
Tenosynovitis of the ECU may also occur after traumatic or degenerative lesions of
the structures responsible for ECU stability, such as the extensor retinaculum and
its deep sheath. We know that the extensor retinaculum is fixed to the radius, ulna,
triquetrum, and pisiform bones, restricting excessive motion of the ECU tendon during
activities requiring wrist flexion and extension, as well as in lateral tilts, and
forearm pronation-supination motion. In addition, in this region, there is a structure
called “linea jugata ,” which is a connection of dense and longitudinally oriented collagen fibers connecting
the deep sheath of the ECU and ulnar styloid process. Its injury generates instability
of the ECU tendon, with pain on the ulnar side of the wrist, mainly during forced
activities of supination, flexion, and ulnar deviation of the wrist; the patient may
also notice a tendon snapping or giving way as it moves in and out of the ulnar groove
during motion.[18 ] Patients with these symptoms were not included in our series and for them, in addition
to synovectomy, some type of ECU stabilization is warranted. Thus, during the ECU
tenoscopy procedure, one of the steps of the surgery should be to test the stability
of the tendon, which can be done by moving the wrist in all planes and under the direct
view of the tendon mobilized with the aid of a probe.
Another common cause of pain in this region is the rupture of the ECU tendon due to
chronic and repeated friction onto bone irregularities, either caused by osteophytes
or fracture sequelae. In these cases, the tendon must be repaired during the procedure
and so must also the bone lesion.
During a tenoscopy of the ECU, it is important to perform a complete synovectomy of
the entire inner part of the sixth extensor compartment, as residual synovitis may
be a cause of postoperative pain. The potential risks of ECU tenoscopy, which include
injury to the tendon, its subsequent instability, and damage to the dorsal sensory
branches of the ulnar nerve are reduced upon the proper performance of the technique
procedure. The proximal portal specific to the ECU tendon is safe and does not cause
damage to the extensor retinaculum because it is created two centimeters proximal
to the retinaculum. In addition, the dorsal sensory branch of the ulnar nerve is located
distal and ulnar to the portal, remaining unharmed during the procedure. Because of
that, we have not had any serious complications related to the procedure in our series.
Conclusion
The use of tenoscopy for the treatment of chronic tenosynovitis of the ECU proved
to be a feasible and effective procedure. It is a reproducible, safe technique that
leads to satisfactory outcomes. If the technique is correctly performed, the synovectomy
is done safely, with no increased risk of ECU and to the dorsal sensitive branch of
the ulnar nerve lesion and neither generates instability nor lesion of the extensor
retinaculum.
It is a minimally invasive procedure with low morbidity, low risk of complications,
and there were no recurrences in our series. We thus present good results with the
treatment of tenosynovitis of the ECU through synovectomy by tenoscopy, which creates
little scarring, the patient is immobilized for a short time, with rapid return to
work and functional recovery. Considering the cost and learning curve, we emphasize
that this technique is a good alternative to the classic open technique.
The advantage of this endoscopic and minimally invasive technique is the possibility
of performing an extensive and safe tenosynovectomy with less scar tissue formation
and less dissection, creating good cosmetic results. We observed less postoperative
pain and stiffness during clinical follow-up, minimizing the risk of dystrophy and
the formation of adhesions. In addition, simultaneous evaluation of differential or
additional diagnoses can be performed, such as the assessment of TFCC, ulnar ligaments
of the wrist, chondral surfaces of the carpus, and distal ulna, among others.
We thus advocate the use of ECU tenoscopy for the treatment of chronic tenosynovitis,
as our series have shown excellent clinical results regarding motion maintenance and
pain resolution, without significant complications or recurrences, and with high rates
of patient satisfaction.
