Extract
Ulnar-sided wrist pain has often been equated with low back pain because of
its insidious onset, vague and chronic nature, intermittent symptoms, and
frustration that it induces in patients. Chronic ulnar-sided wrist pain may be
accompanied by a history of Workers' Compensation claims and unrelenting and
irresolvable pain, and it may occur in patients with difficult personalities.
Despite these issues, many patients with ulnar-sided wrist pain do have
pathologic lesions that may be amenable to surgical treatment.
Ulnar-sided wrist pain has often been equated with low back pain because of
its insidious onset, vague and chronic nature, intermittent symptoms, and
frustration that it induces in patients. Chronic ulnar-sided wrist pain may be
accompanied by a history of Workers' Compensation claims and unrelenting and
irresolvable pain, and it may occur in patients with difficult personalities.
Despite these issues, many patients with ulnar-sided wrist pain do have
pathologic lesions that may be amenable to surgical treatment.
The anatomy of the ulnar side of the wrist is complex, with many
overlapping areas that may be a cause of pain. A clear understanding of the
normal anatomy of the ulnar side of the wrist in addition to a systematic
evaluation with both physical examination and radiographic imaging can often
elucidate the etiology, and thus the treatment, of ulnar-sided wrist pain.
The differential diagnosis of ulnar-sided wrist pain can be divided into
six elements: osseous, ligamentous, tendinous, vascular, neurologic, and
miscellaneous. Osseous injuries include the sequelae of fractures (i.e.,
nonunion or malunion) and degenerative processes. Fracture nonunions of the
hamate1-4,
pisiform5-10,
triquetrum11-13,
base of the fifth
metacarpal14-17,
ulnar styloid process, and distal part of the ulna or radius have been
reported to cause ulnar-sided wrist pain. Degenerative processes at the
pisotriquetral
joint18, midcarpal
(triquetrohamate) articulation, fifth carpometacarpal
joint14-17,
or distal radioulnar joint can also result in substantial ulnar-sided wrist
pain. Ulnar impaction or abutment into the radius or carpus has been reported
as
well19-21.
Ligamentous injuries can occur in any of the ulnar-sided intrinsic
(lunotriquetral or capitohamate) or extrinsic (ulnolunate, triquetrocapitate,
or triquetrohamate) ligaments as well as the triangular fibrocartilage
complex1,18,19,22-27.
Tendinopathies of the extensor carpi
ulnaris18,28-30
or flexor carpi
ulnaris31-34
as well as vascular lesions such as ulnar artery thrombosis or hemangiomas can
also cause ulnar-sided wrist
pain35-38.
Neurologic processes such as entrapment of the ulnar nerve in Guyon's canal,
neuritis of the dorsal sensory branch of the ulnar nerve, and complex regional
pain syndromes may be
present39,40.
Finally, the miscellaneous group includes the very unusual etiologies such as
tumors, including osteoid osteomas, chondroblastomas, and aneurysmal bone
cysts.
The focus of this article is to provide a clear understanding of the
anatomy of the ulnar side of the wrist and to discuss physical examination,
imaging techniques, and treatment of some of the more common causes of
ulnarsided wrist pain.
Extrinsic and Intrinsic Carpal Ligaments
The ulnar portion of the carpus has several intrinsic and extrinsic
ligaments that are important to the stability of the wrist. The intrinsic
ligaments include the capitohamate and lunotriquetral ligaments
(Fig. 1). The lunotriquetral
ligament is a c-shaped ligament with three parts: the dorsal, volar, and
intramembranous portions. Histologically, the dorsal and volar ligaments are
true ligaments, and the volar portion is substantially thicker than the dorsal
portion. The intramembranous ligament is not a true ligament histologically,
and it has little mechanical strength. The capitohamate ligament complex is
formed by three distinct ligaments: the dorsal, volar, and deep
components.
The extrinsic ligaments on the ulnar side include the ulnotriquetral and
ulnolunate ligaments (Fig. 2).
These ligaments act as primary stabilizers of the relationship between the
distal part of the ulna and the volar part of the carpus. The fibers originate
from the volar margin of the triangular fibrocartilage complex, with a
contribution from the base of the ulnar styloid, and insert onto the palmar
aspect of the triquetrum, lunate, and lunotriquetral ligament
(Fig. 3). The fibers are
blended intimately with the volar margin of the triangular fibrocartilage
complex. The meniscus homologue attaches proximally to the dorsal end of the
distal margin of the sigmoid notch and the dorsal border of the triangular
disk. It extends volarly and distally to insert at the ulnar aspects of the
triquetrum, lunate, and lunotriquetral ligament. The ulnar fibers commingle
with those of the subsheath of the extensor carpi ulnaris and continue to the
base of the fifth metacarpal.
Distal Radioulnar Joint
The curvature of the sigmoid notch of the radius is larger than the ulnar
seat and therefore provides little osseous stability to the distal radioulnar
joint. In addition, a dorsal-palmar translation occurs between the joint
surfaces during forearm rotation.
It is understood that, with forearm rotation, motion occurs at the distal
radioulnar joint in three planes: rotation about the longitudinal axis of the
forearm, dorsal-palmar translation, and proximal-distal translation. The
osseous architecture of the distal radioulnar joint affords decreasing
stability with increasing forearm pronation or supination, as the ulnar head
contacts only the volar margin of the sigmoid notch in full supination and the
dorsal margin of the sigmoid notch in full pronation. The ligaments of the
triangular fibrocartilage complex, therefore, provide the primary intrinsic
stabilization of the distal radioulnar joint, with supplemental stability
being provided by the interosseous membrane, the extensor retinaculum, and the
muscle-tendon units that cross the longitudinal axis of rotation of the
forearm. The tendon of the extensor carpi ulnaris serves as a dynamic
stabilizer. Static stability is provided by the subsheath of the extensor
carpi ulnaris.
The volar and dorsal radioulnar ligaments originate from the dorsal and
volar margins of the medial aspect of the radius adjacent to the sigmoid notch
(Fig. 3). They conjoin just
medial to the pole of the distal part of the ulna, forming a triangle that
surrounds the articular disk. There are two separate sites of insertion on the
distal part of the ulna, separated by a band of vascularized loose connective
tissue: the deep fibers of the conjoined ligaments insert into the ulnar fovea
as the ligamentum subcruentum, while the superficial fibers insert into the
base of the ulnar styloid.
Triangular Fibrocartilage Complex
The triangular fibrocartilage complex is the complex of soft tissues
interposed between the distal part of the ulna and the ulnar side of the
carpus, arising from the distal part of the radius and extending across the
ulnar pole to insert into the fovea and the base of the ulnar styloid
(Fig. 3). Considered the
primary stabilizer of the distal radioulnar joint, the term triangular
fibrocartilage complex emphasizes both the functional and the anatomic
interdependence of its elements. Palmer and Werner described the different
components of the triangular fibrocartilage
complex41 as the
triangular fibrocartilage proper (the articular disk), the palmar and dorsal
radioulnar ligaments, the meniscus homologue, the ulnar collateral ligament,
and the subsheath of the extensor carpi ulnaris tendon.
The vascular supply of the triangular fibrocartilage complex has been well
described42.
Supplied by terminal portions of both the anterior and the posterior
interosseous arteries, the palmar, ulnar, and dorsal components of the disk
and radioulnar ligaments are well vascularized, whereas the central and radial
portions are avascular. This pattern of supply has direct implications with
regard to the healing potential of the disk and the radioulnar ligaments
following injury, with peripheral ulnar-sided detachments demonstrating a
superior capacity to heal following repair when compared with radial-sided
detachments.
The etiology of ulnar-sided wrist pain can often be determined on the basis
of a complete history, a detailed clinical examination, and appropriate
diagnostic tests. Once a firm diagnosis has been established, treatment can
ensue.
Ulnar-sided wrist pain can be divided into three categories: acute
traumatic injuries, chronic overuse injuries, and chronic degenerative
problems.
Acute injuries typically result from a notable traumatic event. This may be
a fall from either a height or a standing position, or it may be a
hyperextension injury from a heavy object falling against the wrist. Most
injuries involve a hyperextension, ulnar deviation moment, although flexion
injuries and direct blows may also result in ulnar-sided lesions. Patients may
report hearing a pop and noticing immediate swelling or pain. Injuries such as
a fracture or distal radioulnar joint dislocation may lead the patient to seek
immediate attention, whereas it may take several months for a patient to
present with an injury such as a tear of the lunotriquetral ligament or the
triangular fibrocartilage complex. The patient, however, will typically
remember the index event.
Chronic overuse injuries may have a more indolent presentation. Patients
with chronic repetitive ulnar loading, such as mechanics and plumbers, may
present with vague ulnar-sided pain without a history of specific injury.
Patients with low-grade repetitive loading, such as assembly workers and
computer operators, may present with extensor carpi ulnaris tendinitis
following an increase or change in activity.
Chronic degenerative problems may result from previous acute traumatic
events, previous injuries that have altered the anatomy, and abnormalities
that arise from anatomic or congenital variations. Examples include
ulnar-sided wrist pain resulting from a malunited distal radial fracture, a
previous radial head fracture with subsequent radial shortening, congenital
radial head dislocation, and pisotriquetral arthritis.
A detailed history is essential to determine which of these categories
applies to a particular patient. It must include a detailed medical history as
well as a history of previous injuries and previous surgical procedures
involving not only the wrist but the elbow as well.
Asking the patient about his or her symptoms will often help to narrow the
differential diagnosis of ulnarsided wrist pain. The patient can be asked
whether the pain is ulnar or radial to an imaginary line drawn through the
center of the dorsal aspect of the wrist. Patients with ulnar-sided lesions
are usually able to localize the pain to the ulnar side of the wrist. Patients
often report pain with ulnar deviation and loading of the wrist such as occurs
when they elevate themselves out of a chair or swing a hammer. Patients may
also report pain with hyperextension of the wrist. Occasionally, they report
catching or clicking in the wrist, and this must be further investigated with
a physical examination since noise with wrist motion can be normal. Ulnar
nerve symptoms may point to diagnoses such as a fracture of the hook of the
hamate or more proximal ulnar nerve compression. Vascular symptoms point to
diagnoses such as ulnar artery thrombosis.
The physical examination begins with inspection. The wrist and elbow should
be examined for previous surgical scars. Prominence of the ulna either volarly
or dorsally may indicate some degree of instability of the distal radioulnar
joint. A volar sag and supination of the wrist may indicate the
capsuloligamentous instability that occurs in rheumatoid arthritis. Intrinsic
atrophy and clawing may indicate ulnar nerve neuropathy. Splinter hemorrhages
beneath the nails and decreased turgor in the volar digital pads suggest
vascular insufficiency.
Palpation should proceed in a systematic fashion by isolating anatomic
structures. The examination should be performed with the patient's elbow
resting on the table, the hand pointing toward the ceiling, and the forearm in
neutral as if the patient is about to arm wrestle with the examiner.
Tenderness over any anatomic structure suggests a specific clinical diagnosis.
The lunotriquetral interval is palpated between the fourth and fifth
compartments one fingerbreadth distal to the distal radioulnar joint with the
wrist in 30° of flexion. The extensor carpi ulnaris tendon is palpated
along the distal part of the ulna and is most palpable just distal to the
ulnar head. The extensor carpi ulnaris insertion is at the base of the fifth
metacarpal, well away from the wrist joint
(Fig. 4). The fifth
carpometacarpal joint is just proximal to the extensor carpi ulnaris
insertion. The triangular fibrocartilage complex is best palpated midway
between the extensor carpi ulnaris and the flexor carpi ulnaris in the soft
recess just distal to the ulnar styloid
(Fig. 5). The pisotriquetral
joint is palpated volar to the triangular fibrocartilage complex, and the
pisiform can be moved between the examiner's thumb and index finger. The
distal radioulnar joint is palpated dorsally in various degrees of forearm
rotation.
The differential diagnosis of ulnar-sided wrist pain can be narrowed
further by performing provocative maneuvesrs.
Abnormalities of the lunotriquetral joint can be assessed with three
separate stress maneuvers. Lunotriquetral ballottement can be achieved by
compressing the lunate against the triquetrum. This is performed with the
examiner's thumb placed against the lateral border of the triquetrum and
compressing the triquetrum against the lunate.
The Regan "shuck" test is performed by the examiner placing his
or her thumb and index finger on the triquetrum and pisiform, respectively,
and placing the other hand on the radial carpus and lunate. The examiner moves
his or her right and left hand in opposing (volar and dorsal) directions,
placing shear stress across the lunotriquetral joint. Since the lunate and
triquetrum are the only bones not stabilized, the force is transmitted across
the lunotriquetral joint, with pain indicating a pathologic condition.
The Kleinman "shear" test allows a more subtle application of
force and is considered the most specific provocative test for lunotriquetral
disorders. The examiner places his or her thumb on the pisiform volarly and
the remaining fingers of the same hand dorsally along the ulnar carpus. The
other hand is used to stabilize the lunate and the radial side of the carpus.
Force is generated across the pisiform in a dorsal-to-volar direction while
the other hand is held still. This allows for controlled stress across the
lunotriquetral joint (Fig. 6).
Prior to this maneuver, the pisotriquetral joint should be palpated in the
ulnar-to-radial plane to rule out pathologic changes in this joint.
Pathologic changes in the triangular fibrocartilage complex can be isolated
with the ulnocarpal impaction maneuver. This is again performed with the
patient's elbow flexed and hand pointing toward the ceiling. The examiner
moves the ulnarly deviated wrist in a volar-to-dorsal direction while applying
an axial load across the ulnar side of the wrist
(Fig. 7). This maneuver
translates load across the triangular fibrocartilage complex, which may cause
grinding and reproduce pain.
The piano key test is performed to isolate disorders of the distal
radioulnar joint. Ballottement of the ulna is performed by the examiner
applying a dorsal-to-volar load with his or her hand 4 cm proximal to the
distal radioulnar joint. This isolates abnormalities of the distal radioulnar
joint by avoiding pressure on the overlying structures such as the extensor
digiti minimi tendon.
Selective anesthetic injections are an important adjunct to confirm
pathologic changes suspected on clinical examination. If a corticosteroid is
added to the anesthetic injection, therapeutic benefits may also be achieved.
Injections should be performed in joints or along tendons that are suspected
of being injured. If a lesion of the triangular fibrocartilage complex is
suspected, the injection should be performed in the ulnocarpal joint. If
extensor carpi ulnaris tendinitis is the working diagnosis, then the injection
should be performed in the extensor carpi ulnaris tendon sheath, with
avoidance of the ulnocarpal joint. Such selective injections can be used to
distinguish intra-articular from extraarticular lesions.
Numerous imaging modalities are available for the evaluation of ulnar-sided
wrist pain. In almost all cases, plain radiographs are made first. The
decision to use more advanced imaging modalities is based on the suspected
diagnosis.
Standard Radiographs
Initial radiographic evaluation should include neutral rotation
posteroanterior, neutral rotation lateral, and oblique plain radiographs of
the wrist. These views are useful as a general screening tool to look for
evidence of fractures, arthritic changes, and bone lesions. Numerous indices
can be measured on these
radiographs43.
On the posteroanterior radiograph, particular attention should be paid to
Gilula's lines, ulnar variance, the carpal height ratio, and evidence of
carpal instability. The lateral radiograph is most useful for measurements of
carpal instability, including the scapholunate, capitolunate, and
lunotriquetral angles.
It is important that the posteroanterior and lateral radiographs are made
with the forearm in neutral rotation, as changes in forearm rotation can
influence the measurement of various radiographic indices. For example,
pronation increases ulnar variance and supination decreases
it44. On the
posteroanterior radiograph, neutral rotation can be confirmed by visualizing
the groove of the extensor carpi ulnaris tendon adjacent to the ulnar styloid.
On the lateral radiograph, the anterior surface of the pisiform should project
midway between the anterior aspect of the capitate head and the distal pole of
the scaphoid.
Special Views
In addition to the standard views described above, there are special plain
radiographic views that can provide additional diagnostic information. The
decision to obtain additional views is based on the suspected diagnosis.
Comparison of standard posteroanterior, ulnar deviation posteroanterior,
and radial deviation posteroanterior radiographs may provide indications of
abnormal radiocarpal or midcarpal motion. An ulnar deviation posteroanterior
radiograph, commonly used to show an elongated view of the scaphoid, may also
reveal lunotriquetral instability or evidence of ulnocarpal abutment,
especially when it is compared with a standard posteroanterior radiograph. If
ulnocarpal abutment is suspected, it is often useful to make a posteroanterior
radiograph with the forearm in pronation and the fist clenched, which
increases ulnar variance. Other stress radiographs, such as those made with
dorsal or volar stress on the distal part of the ulna of patients with
suspected instability of the distal radioulnar joint, may also assist in
confirming the diagnosis.
The scaphoid tubercle, the pisiform, and the hook of the hamate are often
difficult to visualize on standard radiographs. A 30° supinated oblique
radiograph is useful to visualize these structures, especially the
pisotriquetral joint and the hamate. A carpal tunnel radiograph is also
useful. However, it is often difficult to make a proper carpal tunnel
radiograph of a patient with an acute wrist injury, as it requires positioning
the wrist in full extension.
Computed Tomography
Computed tomography scans provide better osseous detail than do plain
radiographs. They are very useful in the evaluation of suspected fractures of
bones that are difficult to visualize on plain radiographs, such as the hamate
hook (Fig. 8). Computed
tomography scanning is a very effective modality for the evaluation of a
healing fracture (Fig. 8). In
addition to providing thin-slice axial views of the bones, computer
reconstruction can provide images in any desired plane or can generate
three-dimensional images if needed (Fig.
8).
Computed tomography is the imaging modality of choice for the evaluation of
subluxation of the distal radioulnar joint. The congruity of the distal
radioulnar articular surfaces can also be evaluated accurately. In a study of
computed tomography criteria for the determination of subluxation of the
distal radioulnar joint, Wechsler et al. emphasized the need to obtain
simultaneous views of both extremities with the forearms in neutral rotation,
full supination, and full
pronation45.
Arthrography
In the past, arthrography had been the favored imaging modality for the
evaluation of ruptures of the interosseous ligaments and tears of the
triangular fibrocartilage complex. Triple-injection arthrography had been
considered the "gold" standard for detecting perforations of the
triangular fibrocartilage complex. However, several authors have maintained
that arthrography of the wrist is much less accurate than arthroscopy and that
it has a relatively high rate of false-negative
findings20,46.
Others have pointed out the poor correlation between arthrographic findings
and symptoms reported by
patients47-49.
Zanetti et al. suggested that this poor correlation is due to a dependence on
the detection of communicating defects of the triangular fibrocartilage
complex50. Those
authors suggested that careful attention to detail allows detection of
noncommunicating defects of the triangular fibrocartilage complex, which have
a more reliable association with symptomatic ulnar-sided lesions of the
triangular fibrocartilage
complex50.
Over the past several years, arthrography has been largely supplanted by
magnetic resonance imaging for the evaluation of lesions of the triangular
fibrocartilage complex. However, arthrography continues to be used to evaluate
the integrity of the scapholunate and lunotriquetral interosseous ligaments
(Fig. 9). The value of
arthrography may be increased by the simultaneous use of real-time
fluoroscopic imaging.
Fluoroscopy
Abnormal motion of the carpal bones can be most accurately demonstrated
with real-time fluoroscopic imaging. In particular, in patients who
demonstrate a sudden shift or clunk with wrist deviation, the site of the
pathologic entity can often be identified fluoroscopically. When a patient has
an injury of the lunotriquetral interosseous ligament, fluoroscopy may
demonstrate the so-called catch-up of the triquetrum moving into extension as
the wrist moves from radial to ulnar
deviation19.
Fluoroscopy is similarly useful for demonstrating dynamic instabilities in
patients with instability of the scapholunate, midcarpal, or distal radioulnar
joint.
Radionuclide Imaging
Radionuclide imaging, or bone-scanning, provides excellent sensitivity for
the detection of occult or nondisplaced fractures. A single-phase scan is
sufficient for the detection of fractures if additional information, such as
the status of osseous blood flow, is not required. Bone scans are very
sensitive to the locations of pathologic lesions of bone, but they often do
not provide a definite diagnosis. The modality is a useful, relatively
low-cost screening tool for the evaluation of occult fractures, osteonecrosis,
and osteomyelitis. The relative value of bone-scanning compared with computed
tomography for the evaluation of occult fractures on the ulnar side of the
wrist has not been determined, and some have suggested that magnetic resonance
imaging is as useful as bone-scanning for detecting an occult
lesion51. If such a
lesion is found, a subsequent computed tomography scan is the most accurate
modality for evaluating the osseous details of the fracture, if that
information is needed. Radionuclide imaging may also be useful for the
evaluation of complex regional pain syndromes.
Magnetic Resonance Imaging
Magnetic resonance imaging is the procedure of choice for the assessment of
a wide range of soft-tissue lesions, including ligament and cartilage lesions,
soft-tissue tumors, tendinitis, and joint effusions. While computed tomography
provides superior osseous detail, magnetic resonance imaging may have greater
sensitivity for the detection of subtle changes such as bone edema and is
therefore particularly useful for the evaluation of occult fractures and
stress fractures. Magnetic resonance imaging clearly provides a great deal
more anatomic detail than does arthrography alone. Magnetic resonance imaging
with use of a dedicated wrist coil and combined with arthrography may supplant
magnetic resonance imaging alone for the diagnosis of intercarpal and
triangular fibrocartilage complex abnormalities. Recently, techniques
combining magnetic resonance imaging with single-injection gadolinium
arthrography have been developed (Figs.
10-A and
10-B), but their use has not
been thoroughly studied. After injection of gadolinium into the radiocarpal or
the midcarpal joint, contrast medium leaking into the distal radioulnar joint
or into the radiocarpal joint can be indicative of a tear of the triangular
fibrocartilage complex or an injury of the intercarpal ligament. Magnetic
resonance imaging can also provide information concerning the vascular status
of the lunate and the ulnar head, which is valuable in the diagnosis of
ulnocarpal
abutment21.
Magnetic resonance imaging has become widely used for the evaluation of
tears of the triangular fibrocartilage complex. Early studies demonstrated
that magnetic resonance imaging had poor accuracy for predicting the location
of such tears seen at
arthroscopy52,53.
In one recent study, magnetic resonance imaging had an accuracy of 92% for
predicting tears of the triangular fibrocartilage
complex54; however,
other authors have suggested that this level of accuracy may be somewhat lower
in most clinical settings and is highly dependent on the experience of the
individual interpreting the magnetic resonance imaging
scans55. Magnetic
resonance imaging has not yet proven reliable for the detection of tears of
the lunotriquetral
ligament19,56.
Wrist Arthroscopy
Arthroscopy can serve as an important tool in the diagnosis and treatment
of ulnar-sided wrist pain. Although diagnostic modalities such as magnetic
resonance imaging and arthrography are helpful, arthroscopy is considered the
gold standard for diagnosing and staging of intra-articular lesions. Tears of
the scapholunate and lunotriquetral ligaments can be graded by visualizing
them through both the radiocarpal and the midcarpal portal. Partial tears can
be appropriately débrided, and complete tears can be prepared for
reconstruction. Central tears of the triangular fibrocartilage complex can be
débrided arthroscopically, and peripheral tears can be repaired with
arthroscopic assistance. Isolated areas of arthritis are often difficult to
diagnose with other modalities. Arthroscopy allows the staging of degenerative
or posttraumatic arthritis and can help the surgeon to determine which
reconstructive procedures or limited fusions are appropriate. Arthroscopy of
the distal radioulnar joint allows staging of arthritis of that joint.
Furthermore, loose bodies and cartilage flaps that are difficult to visualize
with other modalities can be seen and removed. Finally, normal arthroscopic
findings allow the examiner to exclude intercarpal ligament, triangular
fibrocartilage complex, and articular lesions as sources of pain and should
lead him or her to look for pathologic changes elsewhere.
Triangular Fibrocartilage Complex and Distal Radioulnar Joint
Palmer classified lesions of the triangular fibrocartilage complex as
either traumatic (Type 1) or atraumatic (Type 2)
(Fig.
11)57.
Division of each group into subtypes, with Type-1 lesions classified on the
basis of the structure that is disrupted and Type-2 lesions classified on the
basis of the extent of the degenerative process, can direct treatment.
Definitive treatment of traumatic or degenerative lesions of the triangular
fibrocartilage complex remains controversial. Although there are exceptions,
in general Type-1 lesions are treated either with immobilization or surgical
repair, whereas Type-2 lesions can be treated either with a splint,
anti-inflammatory drugs, or cortisone injection or with arthroscopic
débridement or ulnar shortening osteotomy.
Chronic radial or ulnar-sided detachment of the triangular fibrocartilage
complex can lead to symptomatic instability (clunking on forearm rotation) or
pain in the distal radioulnar joint secondary to degeneration of the articular
cartilage of the sigmoid notch and the ulnar seat. Previous injury to the
distal part of the radius (intra-articular fracture of the sigmoid notch) or
to the ulnar seat can likewise lead to cartilage degeneration and symptomatic
arthritis. Patients experience pain with forearm rotation and tenderness on
palpation of the distal radioulnar joint. Surgical treatment should attempt to
address both the arthritis of the distal radioulnar joint and the distal ulnar
instability.
Lunotriquetral Instability
Several factors should be considered when choosing the optimal treatment
for lunotriquetral
injuries19. These
include the amount of instability (static or dynamic), the elapsed time
between the injury and treatment (acute or chronic), and the presence of
associated injury or degenerative changes. Pain associated with lunotriquetral
tears may be due to dynamic instability and/or local synovitis. The initial
management of almost all acute and chronic tears without a dissociation or
volar intercalated segmental instability should probably be conservative, with
cast or splint immobilization. Careful cast-molding with a pad underneath the
pisiform maintains optimal alignment as healing progresses. Midcarpal
corticosteroid injections can be helpful to decrease synovitis. Operative
treatment is indicated for acute and chronic dissociations that demonstrate a
volar intercalated segmental collapse and chronic tears that are unresponsive
to conservative management. The goal of surgical intervention is realignment
of the lunocapitate axis and reestablishment of the rotational integrity of
the proximal carpal row. A variety of procedures have been described,
including lunotriquetral arthrodesis, ligament repair, and ligament
reconstruction. If concomitant ulnar negative or positive variance or
midcarpal or radiocarpal arthrosis is present, additional procedures such as
ulnar lengthening or shortening, midcarpal arthrodesis, or proximal row
carpectomy may be indicated. Total wrist arthrodesis may be indicated when
degenerative changes make other salvage procedures impossible.
Repair of the lunotriquetral ligament has been described by several
authors58,59.
The lunotriquetral interosseous ligament is reattached to the site of its
avulsion, which is generally the triquetrum. As the strong volar ligament is
also disrupted, a combined dorsal and volar approach as well as augmentation
of the repair by plication of the dorsal radiotriquetral and dorsal
scaphotriquetral ligaments may be of some value. Protracted immobilization is
then necessary.
Patients who engage in strenuous pursuits or have chronic instability or a
poor-quality lunotriquetral ligament may be best managed with ligament
reconstruction rather than repair. Ligament reconstruction with a distally
based strip of extensor carpi ulnaris tendon graft is one option. Unlike
reconstruction of the scapholunate ligament, this technique, although
demanding, has yielded uniformly good results in two
studies58,59.
Unlike lunotriquetral arthrodesis, reconstruction preserves lunotriquetral
motion and provides the optimal chance for restoration of normal carpal
interactions.
The observation of asymptomatic congenital lunotriquetral coalitions and
the relatively little relative motion that normally occurs between the lunate
and triquetrum led to the concept of lunotriquetral arthrodesis. It may be
technically less demanding than ligament reconstruction or repair, and it has
become the technique of choice of many surgeons. However, the method is not
without substantial problems. The reported nonunion rate has ranged from 0% to
57%19. Use of
Kirschner wires has been shown to result in an unacceptably high nonunion rate
of
47%19,59.
Use of compression screws may improve results, but nonunion remains a major
problem. A 9% nonunion rate has been reported with the Herbert screw, and the
use of conventional cortical screws may be associated with nonunion rates as
high as
57%19,59.
Ulnocarpal impingement required additional surgery in 23% (five) of twenty-two
patients treated with lunotriquetral arthrodesis in one
series59. This
complication was not seen with lunotriquetral repair or reconstruction. A
comparison of the results following arthrodesis, ligament repair, and
reconstruction at the Mayo Clinic demonstrated that repair and reconstruction
were superior to
arthrodesis59. The
lower complication rates, higher patient satisfaction, greater range of
motion, and fewer subsequent reoperations led the Mayo Clinic group to prefer
repair or reconstruction of the lunotriquetral ligament as their primary
method of treatment for lunotriquetral injuries that require surgical
intervention (Fig. 12).
Tendinopathies
Tendinopathies of the wrist are relatively common causes of ulnar-sided
wrist pain. On the dorsal side of the wrist, the extensor carpi ulnaris and,
less commonly, the extensor digiti minimi may be involved; on the flexor
surface, the flexor carpi ulnaris and/or the pisiform may be involved.
An understanding of the anatomy of the extensor carpi ulnaris and its
surrounding structures is essential for the diagnosis and management of
extensor carpi ulnaris
tendinitis60. The
extensor carpi ulnaris tendon sits in a groove, or sulcus, at the distal part
of the ulna. It is maintained within this groove during forearm rotation by
the extensor retinaculum and a subsheath, which forms a fibro-osseous tunnel.
The linea jugata connects the subsheath to the epimysium and prevents
subluxation of the extensor carpi ulnaris in a palmar direction during full
supination. Normally, the extensor carpi ulnaris tendon sits in the ulnar
sulcus and helps to stabilize the distal radioulnar joint as the forearm moves
from pronation to supination. If the extensor carpi ulnaris displaces in a
volar direction during supination, it may cause the tendon to move out of the
sulcus, often resulting in a painful snapping sensation and inflammation. The
depth of the ulnar sulcus varies, and subluxation is more likely to occur if
it is shallow. In the case of a traumatic dorsal subluxation or dislocation of
the ulnar head, the extensor carpi ulnaris may be forcibly displaced volarly
and there is often disruption of the triangular fibrocartilage complex. In
addition, the extensor carpi ulnaris subsheath may rupture, with or without
disruption of the extensor retinaculum. This may happen with forceful radial
deviation with flexion of the wrist, which is seen in patients participating
in activities such as baseball and rodeo. In patients with inflammatory
disorders such as rheumatoid arthritis, attritional wear of the supporting
structures may lead to subluxation of the extensor carpi ulnaris and extensor
digiti minimi without a specific traumatic event.
Patients with extensor carpi ulnaris tendinitis due to subluxation may
present with a painful snap or click during forearm
rotation18,28-30.
Often, there is tendinitis without detectable instability. In such cases,
there may be tenderness at the distal part of the ulna, over the fifth
(extensor digiti minimi) or sixth (extensor carpi ulnaris) dorsal compartment.
Extensor digiti minimi tendinitis presents with pain or tenderness over the
fifth dorsal compartment of the wrist. Less commonly, there is inflammation at
the insertion of the extensor carpi ulnaris, which presents with pain and
inflammation at the dorsal base of the fifth metacarpal.
Acute treatment of a traumatic injury involving the extensor carpi ulnaris
tendon includes reduction of a distal radioulnar joint dislocation, if
present, followed by immobilization of the wrist and forearm, rest,
application of ice, and use of nonsteroidal anti-inflammatory medications. The
forearm is usually immobilized in the neutral position, although it is
sometimes necessary to immobilize it in supination to maintain reduction of
the distal radioulnar joint after a dorsal dislocation. Subsequently, the
distal radioulnar joint is stabilized by repair of the triangular
fibrocartilage complex. The extensor carpi ulnaris tendon is stabilized by
reconstruction of the extensor carpi ulnaris subsheath, with use of a flap of
extensor retinaculum passed around the tendon as described by Spinner and
Kaplan60. This
procedure allows the extensor carpi ulnaris tendon to remain within the ulnar
sulcus during forearm and wrist rotation.
In patients with subluxation of the extensor carpi ulnaris due to
inflammatory arthritis, dorsal subluxation of the ulnar head often must be
addressed in addition to reconstruction of the extensor carpi ulnaris
subsheath. Numerous procedures have been described for this purpose, and the
choice of procedure is determined by the clinical presentation and the
surgeon's preference.
In the case of nontraumatic tendinitis of the extensor carpi ulnaris or
extensor digiti minimi tendon, the mainstay of treatment is rest, brief
periods of immobilization, nonsteroidal anti-inflammatory drugs, and judicious
use of corticosteroid injections. Surgery is rare and is reserved for chronic,
recalcitrant cases. Insertional tendinitis of the extensor carpi ulnaris is
treated with transfer of the extensor carpi ulnaris to the dorsum of the
hamate. Tendovaginitis within the extensor sheath is treated with release of
the extensor carpi ulnaris subsheath and reconstruction, as described above.
If the extensor digiti minimi is involved, simple release of the fifth dorsal
compartment has excellent results.
Treatment of tendinitis of the flexor carpi ulnaris similarly requires an
understanding of the local anatomic
structures31,32.
The ulnar neurovascular bundle lies on the radial side of the flexor carpi
ulnaris tendon just proximal to the wrist joint. It passes radial to the
pisiform at Guyon's canal. The flexor carpi ulnaris is a large muscle and the
most powerful wrist motor. It does not have a synovial sheath. It inserts into
the proximal and anterior aspect of the pisiform, a sesamoid bone located
within the flexor carpi ulnaris tendon that has a single articular surface,
which articulates with the volar surface of the triquetrum. As there is no
inherent stability of the pisotriquetral joint, stability depends on the
pisohamate and pisometacarpal ligaments, which attach to the pisiform like
spokes on a
wheel61. Flexor
carpi ulnaris tendinitis has an insidious onset. Patients present with aching
pain on the ulnar flexor side of the wrist. The symptoms may be related to
repetitive or overuse activities. There is tenderness near the insertion of
the flexor carpi ulnaris on the pisiform and pain on resisted wrist flexion
and ulnar deviation. Patients may present with associated ulnar nerve
symptoms.
Pisotriquetral arthritis and, less commonly, pisotriquetral instability are
causes of ulnar-sided wrist pain that may be misdiagnosed as flexor carpi
ulnaris tendinitis. Pisotriquetral arthritis is associated with local pain and
tenderness, which are exacerbated by grinding of the pisiform dorsally against
the triquetrum. Instability may be subtle and more difficult to diagnose. A
diagnostic injection of local anesthetic in combination with appropriate
radiographic imaging will confirm both diagnoses.
Flexor carpi ulnaris tendinitis is most commonly treated
nonoperatively31,32.
As is the case for other soft-tissue conditions, it usually can be treated
with rest, immobilization, nonsteroidal anti-inflammatory drugs, and, rarely,
corticosteroid injection. Surgical treatment is rare and, if it is undertaken,
the ulnar neurovascular bundle must be identified and protected. Flexor carpi
ulnaris tendinitis that does not respond to nonoperative treatment may be
relieved by z-plasty lengthening of the tendon proximal to its insertion on
the pisiform. If the pathologic process primarily involves the pisiform,
excision of the pisiform is the most commonly used surgical procedure.
Unusual causes of ulnar-sided wrist pain include those of neurogenic
origin, vascular origin, and atypical fractures.
Ulnar nerve compression at Guyon's canal typically presents with fatigue,
weakness, and the feeling of loss of coordination with fine motor
activities62.
Patients may have decreased sensation in the ring and small fingers but not on
the dorsum of the hand since the dorsal sensory nerve branch originates more
proximally. The diagnosis is made with nerve conduction studies and
electromyography. Compression of the ulnar nerve in Guyon's canal may result
from a mass effect, thrombosis of the ulnar artery, or a fracture of the hook
of the hamate. Magnetic resonance imaging should be considered to determine if
any of these factors, which can be treated with surgical decompression, are
contributing to the ulnar nerve compression
(Fig. 13).
Thrombosis of the ulnar artery (Fig.
14) otherwise known as hypothenar hammer syndrome, typically
results from repetitive force against the ulnar artery as is seen in plumbers
or other workers who use high-impact
equipment35. More
unusual causes include systemic conditions or a more proximal vascular event.
Patients present with pain associated with cold exposure, splinter
hemorrhages, and decreased turgor in the ulnar digits. The diagnosis is
suspected on the basis of abnormal results of the Allen test and can be
confirmed with Doppler studies. Surgical planning requires an arteriogram.
Surgical treatment consists of either resection alone or resection combined
with vascular reconstruction.
Although ulnar-sided wrist pain can be intimidating and confusing, it can
be broken down into the fundamental elements and evaluated in a systematic
fashion. A probable diagnosis can be made on the basis of a detailed history
and a clinical examination of all of the entities that can cause ulnar-sided
wrist pain. The diagnosis is then confirmed by appropriately selected
radiographic studies. Anesthetic injections (with corticosteroids) can be
utilized as a diagnostic tool as well as a therapeutic measure. Once the
diagnosis is made, treatment (both conservative and operative) should be
directed at restoring normal anatomy whenever possible.
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