We performed a retrospective study of patients with radiocarpal
dislocation. Only patients for whom initial radiographs were available
were included.
We included patients in whom the entire carpus had been dislocated
volar or dorsal to the radius. An associated fracture of the radial
styloid process was not a reason for exclusion provided that the
ulnar half of the distal part of the radius was intact. Carpal translations
associated with a fracture of the volar or dorsal margin of the
radius (Barton fracture) were eliminated from the study, as were
intracarpal dislocations.
Age, gender, and associated injuries at the time of the dislocation
were noted. Plain radiographic analysis detailed the direction of
the dislocation (volar or dorsal), associated lesions of the distal
radioulnar joint, and fracture of the radial styloid process. Two
groups of patients were defined. Group 1 included those with pure
radiocarpal dislocation with or without a fracture of only the tip
of the radial styloid process-that is, a fracture involving less
than one-third of the width of the scaphoid fossa. We postulated
that the radiocarpal ligaments were torn off the radius in this
group. Group 2 included patients with radiocarpal dislocation and an
associated fracture of the radial styloid process that involved
more than one-third of the width of the scaphoid fossa. We postulated
that most of the radiocarpal ligaments were still intact and attached to
the radial fragment in this group.
Operative records were analyzed for the type of reduction, ligamentous
reconstruction, and fixation.
At the time of the latest follow-up, we performed a clinical
evaluation of both wrists that included an assessment of pain (with
use of a verbal scale), wrist motion (as measured with a goniometer),
and grip strength (as measured with a Jamar dynamometer [TEC, Clifton,
New Jersey]). Plain radiographs were reviewed for evidence of malunion
of the radial styloid process, degenerative arthritis of the carpus,
or problems involving the distal radioulnar joint.
From 1975 to 1998, we observed twenty-seven cases of acute radiocarpal
dislocation (see Appendix). Four were displaced volarly and twenty-three were
displaced dorsally. Twenty patients were male and seven were female,
and the average age (and standard deviation) was 32.3 ± 9.8 years (median, thirty years; range, eighteen
to fifty-eight years). Thirteen right wrists and thirteen left wrists
were dislocated, and in one case the side was not recorded. All
dislocations were closed injuries. In no case were we able to define
the precise mechanism of injury, but we postulated that this is
a severe injury as at least fourteen patients presented with associated
injuries (Fig. 1Fig.
1). Two other patients had acute median-nerve compression, five
patients had no associated injuries, and medical data were lacking
for six patients.
At the time of injury, fourteen patients presented with an injury
of the ipsilateral distal radioulnar joint. One of these patients
had an irreducible dislocation of the distal radioulnar joint due
to the interposition of the flexor digitorum profundus of the small
finger (Figs. 2-AFigs.
2-A, 2-B2-B,
and 2-C2-C).
Four patients had severe instability of the radioulnar joint, which
necessitated radioulnar stabilization with Kirschner wires. The
other nine patients had a fracture of the ulnar styloid process.
Four patients were treated with closed reduction and immobilization
in a long arm cast; five, with percutaneous Kirschner wire fixation
and cast immobilization; and two, with an external fixator. Eleven
patients had open reduction with Kirschner wire fixation and cast
immobilization; five of these patients also had a ligamentous suture,
and one had bone-grafting. The details of the treatment were not known
for five patients.
In Group 1, two patients had a pure dislocation; one of these
dislocations was volar and the other was dorsal (see Appendix).
With the patient under anesthesia, both dislocations proved to be
highly unstable, with persistent subluxation and ulnar translation
after closed reduction, and both required percutaneous Kirschner
wire stabilization (Figs. 3-AFigs. 3-A, 3-B3-B, and 3-C3-C).
Two patients in Group 1 had dorsal radiocarpal dislocation with
an associated fracture of the ulnar styloid process. One, who was
treated with closed reduction and cast immobilization, had ulnar
translation of the carpus while the limb was still in the cast (Fig. 4Fig. 4). He refused
further treatment, and after six years of follow-up he was still
able to work as a garage mechanic.
Three patients in Group 1 had dorsal radiocarpal dislocation
with a fracture of the tip of the radial styloid process. A global
ulnar translation of the carpus developed in two of these patients,
whereas the third patient had an ulnar translation of the carpus
with a scapholunate gap that appeared later.
The patients in Group 2 presented with radiocarpal dislocation
and an associated fracture of the radial styloid process that involved
more than one-third of the width of the scaphoid fossa. The radial
fracture was very horizontal and never passed ulnar to the scaphoid
fossa (Figs. 5-AFigs.
5-A and 5-B5-B).
We hypothesized that this fracture represents an avulsion injury
of the insertion site of the volar radiocarpal ligaments. Posteriorly,
the ligamentous injury presented most often as a capsuloperiosteal avulsion.
Three patients in Group 2 presented with volar radiocarpal dislocation.
Two of them had an associated radial fracture through the scaphoid
fossa, and one had only a chip fracture of the volar margin of the
radius. All were lost to follow-up within three months. Seventeen
patients presented with dorsal radiocarpal dislocation and a fracture
of the radial styloid process through the scaphoid fossa. Two were
lost to follow-up. Thirteen patients had adequate follow-up (see
Appendix).
All four patients with volar dislocation in the series were lost
to follow-up. Of the twenty-three patients with dorsal dislocation,
eighteen were evaluated at an average of 44.3 ± 41.6
months (median, twenty-four months; range, three to 135 months).
Five patients in Group 1 were evaluated at an average of 26.8 ± 25.4 months (median, eighteen months; range, ten to
seventy-two months). Four of these patients reported slight pain
and one, moderate pain. Pronation averaged 76 ± 15.1
(median, 80; range, 60 to 90); supination, 66 ± 16.7
(median, 70; range, 40 to 80); wrist flexion, 54 ± 15.5
(median, 50; range, 40 to 80); wrist extension, 54 ± 17.8 (median, 45; range, 40 to 80); radial inclination,
15 ± 5.0 (median, 15; range, 10 to 20); and
ulnar inclination, 18 ± 7.6 (median, 20;
range, 10 to 25). Grip strength averaged 27 ± 2.8
kg (median, 33 kg; range, 12 to 37 kg). One wrist was highly unstable
at the time of injury. This injury was fixed with Kirschner wires,
and, at sixteen months, fluoroscopic evaluation showed the carpus
to be stable. Ulnar translation of the carpus developed in the other
four patients, without scapholunate dissociation in three and with scapholunate
dissociation in one.
Thirteen patients in Group 2 were evaluated at an average of
51 ± 46.8 months (median, twenty-four months;
range, three to 135 months). Six reported no pain; four, slight
pain; and two, moderate pain. One patient had a completely flail
upper extremity due to brachial plexus injury. Pronation averaged
63 ± 27.1 (median, 70; range, 10 to 90);
supination, 76 ± 10.3 (median, 80; range,
50 to 80); wrist flexion, 51 ± 17.0 (median,
58; range, 5 to 65); wrist extension, 56 ± 13.1
(median, 60; range, 25 to 75); radial inclination, 21 ± 10.2 (median, 23; range, 0 to 35); and ulnar inclination,
39 ± 13.7 (median, 43; range, 15 to 60).
Grip strength averaged 38 ± 10.1 kg (median,
42 kg; range, 18 to 47 kg).
Seven patients had complications. In one, septic arthritis developed
in association with Kirschner wire fixation; it was treated with
splints and intravenous antibiotics. The patient subsequently had
a distal ulnar resection to treat a lack of forearm rotation. One
patient subsequently was treated with a Sauv�-Kapandji procedure.
Posttraumatic arthritis developed in three patients as a result
of a persistent articular step-off. One patient had a secondary flexor
tendon rupture. Another patient had a persistent chronic dorsal
subluxation of the carpus on radiographs but was not available for
clinical examination.
We think that our classification facilitates treatment of this
injury. The first group included pure radiocarpal dislocations and
radiocarpal dislocations associated with a fracture of the tip of
the radial styloid process. The second group included radiocarpal
dislocations associated with a fracture of the radius through the
scaphoid fossa.
The main problem with our study is that it was retrospective
and only included patients for whom radiographs were available.
However, to our knowledge this is the largest series presented to
date, without selection of the patients, and our data are similar
to those previously reported in the literature10.
As with most violent trauma, the lesion was most commonly observed
in men (74% of the present series); the average age of our patients
was thirty-two years (range, eighteen to fifty-eight years). As a
result of the violence of the injury, associated lesions were frequent.
Associated fractures or dislocations, open injuries, tendon ruptures,
and neurovascular injuries have all been previously reported1,4,11,12,16-21.
The exact mechanism of injury was impossible to determine in
our patients. The postulated mechanism of posterior dislocation
is an association of hyperextension, pronation, and radial inclination6,11,17,19-22. It is thought that dislocation
is made possible by rotational movement, a mechanism that is consistent
with the high frequency of distal radioulnar joint injuries and/or
sequelae reported in this and other series11,17,18,20,21,23.
Dodd is the only author, to our knowledge, who reported the possibility
of a hyperflexion mechanism16.
Division of our patients into two groups was based on anatomic
considerations. The most important radiocarpal ligaments insert
on the radial aspect of the volar margin of the radius2,24. Our retrospective review involved
patients who had been treated without consideration of the two groups.
Therefore, we believe that there was no bias in the selection of
treatment.
Group-1 radiocarpal dislocations are very rare10.
Anatomic descriptions11,20,21,25,
experimental studies19,24, literature
reviews4,10,17,18,22,23,25-27,
and our own surgical experience suggest that all volar radiocarpal
ligaments are torn in this group. Sometimes, instead of these ligamentous
tears, patients have an avulsion fracture at the insertion site
of the ligaments18,20. Posteriorly,
the ligamentous injury presented most often as a capsuloperiosteal
avulsion rather than as a rupture of the dorsal radiocarpal ligaments.
Ligamentous injuries are the reason why these lesions are so unstable,
usually in more than one direction23,26.
Ulnar and volar translation of the carpus was common in Group 1.
Translation, both acute22,23,25,26,28 and
secondary6,22,25,27,29, has been
reported previously. Functional results have usually been poor6,22,25-29, and late arthritis may
develop27,28. Patients with a
fracture of the tip of the radial styloid process (less than one-third
of the width of the scaphoid fossa) should be included in Group
1, as our three patients with this type of fracture had secondary
ulnar translation of the carpus.
Group 1 had satisfactory short-term functional results, with
satisfactory wrist mobility, slight-to-moderate pain, and the patients
returning to the work in which they were engaged before the injury. However,
all but one of the patients had secondary ulnar translation of the
carpus, regardless of the method of treatment that had been used.
The only patient who did not have recurrent instability was the
only one who had temporary radiolunate fixation. As five of the
six patients had translation after treatment, we now advocate more
aggressive treatment. Open reduction and ligamentous repair through
a volar approach, with Kirschner wire fixation of the lunate under
the radius for two months, is currently performed. Postoperative
volar translation has not been reported in the literature to our knowledge,
and none of our patients had late volar translation.
In Group 2, the volar radiocarpal ligaments were probably intact
and remained attached to the fractured radial fragment. The fracture
was probably secondary to impaction of the carpus into the radius11,17,18. This fracture usually included
all of the scaphoid fossa and may continue on the dorsal margin.
The first case of radiocarpal dislocation with fracture of the
scaphoid fossa in the radiographic era was reported by Destot in
19041. Functional results after
that injury have usually been good, regardless of the type of treatment4,13,14,18,19,21. However, Schoenecker
et al. reported that four of six patients had arthritis after three
years of follow-up20. Moneim et
al. reported that, of four patients who had been treated surgically,
one had early stiffness and two had a fair result4.
The six patients in the series reported by Le Nen et al. had limitation
of wrist motion (a flexion-extension arc of about 90º), three had
pain during activity, and five had some narrowing of the radiocarpal joint18. The articular surface of the radius
was irregular in three patients, and there was ossification between the
radiocarpal joint and the distal radioulnar joint in two. However,
all of the patients returned to their previous jobs. All patients
reported on by Nyquist and Stern had a poor functional result, with
arthritis and a flexion-extension arc of 57º on the average12. However, all had sustained very
severe injuries with an open dislocation.
Our results, which included a 35% limitation of wrist mobility,
were more similar to the less encouraging published results. Secondary
arthritis in our series was due to either a complication or an incomplete
reduction. However, patients were usually pain-free or had only
slight pain, which may explain why results have been considered
good after short periods of follow-up. Our results are inferior
to previously reported results, and we believe that our patients
with articular incongruency will probably have deterioration with
time.
Since the radiocarpal ligaments are attached along the volar
rim of the scaphoid fossa as well as the styloid process, fixation
of the fracture fragment is the most important step in the treatment
of Group-2 patients. Anatomic reduction of the radial fragment proved
difficult in our series. We believe that Group-2 patients should
be treated with open reduction through a dorsal approach with Kirschner wire
fixation of the radial styloid process. In some instances a bone
graft may be needed18,20. Complementary
fixation with either a cast or an external fixator for at least
six weeks is probably necessary. Other authors have also considered immediate
surgery and fixation of the radial styloid process as primary treatment
to stabilize the carpus and to avoid any displacement11,20,21. Surgical exposure was useful
for the removal of the chondral fragments as well18.
Secondary ulnar or volar translation of the carpus has not been
reported in patients with radiocarpal dislocation and a fracture
of the scaphoid fossa, to our knowledge. This may be explained by
the integrity of the volar radiocarpal ligaments, which are still
attached to the radial fragment.
We believe that radiocarpal dislocations should be classified
into two groups. The first group includes pure radiocarpal dislocations
and radiocarpal dislocations with a fracture of the tip of the radial
styloid process. In this group the volar radiocarpal ligaments are
torn from the radius, and consideration should be given to ligamentous
repair to avoid secondary ulnar and/or volar translation. The second group
includes patients in whom the volar radiocarpal ligaments are still
attached to the radial scaphoid fossa, which is fractured. Exact
articular reduction through a dorsal approach is the preferred treatment.
With adequate reduction and fixation, functional results will be
satisfactory in both groups. However, functional results mostly
depend on the articular damage and the associated wrist injuries,
including those involving the distal radioulnar joint. Prospective
studies with use of our classification will be required to validate
our hypotheses.