Hinged Elbow External
Fixators: Indications and
Uses
Abstract
Hinged external fixation of the elbow joint can play an important
role in managing complicated fracture-dislocations, joint instability
after extensive contracture release, and distraction interposition
arthroplasty. Application of these devices requires accurate
alignment of the fixator axis with the anatomic axis of the elbow.
The primary therapeutic goal is to allow joint motion while
protecting the healing ligaments. Common complications include
pin loosening, injury to adjacent neurovascular structures,
cellulitis, and loss of reduction. Although reported data are limited,
this technique is a useful adjunct in patients with complex elbow
instability.
S
ince Malgaigne first described ex-
ternal fixation for patellar frac-
tures in 1843, external fixators have
evolved from simple devices used
exclusively in lower extremity trau-
ma to articulating hinged frames
with applications in the upper ex-
tremity. Although originally de-
scribed in the Russian literature in
the early 1970s, the first English-
language report of a hinged distrac-
tion apparatus for the elbow did not
appear until 1975.
1
This hinged

lows concentric ulnohumeral mo-
tion while protecting the joint sur-
faces and periarticular soft tissues
from loads that would injure or dis-
rupt the healing tissue. The several
commercial devices now available
that seek to satisfy this requirement
differ in design, method of mobiliza-
tion, and technique of application.
Common Design and
Application Features
Elbow fixators are categorized as
unilateral ormultiplanar. These two
types share common design features
and are affixed using essentially
similar surgical techniques. Advan-
Virak Tan, MD,
Aaron Daluiski, MD,
John Capo, MD, and
Robert Hotchkiss, MD
Dr. Tan is Associate Professor, Division
of Hand and Microsurgery, Department
of Orthopaedic Surgery, University of
Medicine and Dentistry of New Jersey–
The New Jersey Medical School,
Newark, NJ. Dr. Daluiski is Assistant
Professor, Division of Hand Surgery,
Department of Orthopaedic Surgery,
The Hospital for Special Surgery, New
York, NY. Dr. Capo is Assistant

irritation; a lower profile, which is
more tolerable to the patient; and
ease of application. Advantages of
the multiplanar fixators include
more rigid skeletal fixation as well
as better control of varus/valgus
alignment and joint distraction.
Application of a hinged elbow
external fixator can be demanding.
The most critical step is correct
placement of the axis pin. To mini-
mize resistance to motion and half-
pin loosening, this pin must be
colinear with the center of rotation
of the elbow joint. Madey et al
5
re-
ported that misalignment of 5°
caused a 3.7-fold increase in motion
energy; a 10° mismatch yielded a
7.1-fold increase. The anatomic axis
of rotation lies at the center of the
capitellum and trochlear spool and is
usually determined from anatomic
landmarks. Medially, this point lies
just distal and anterior to the medi-
al epicondyle; laterally, it lies just
slightly distal to the lateral epi-
condyle.
The axis pin starting point should

Lateral pins are more easily placed
because of patient positioning. The
most proximal lateral pin may lie
near the course of the radial nerve,
which should be avoided by careful
pin placement. Pins placed medially
should be inserted through an open
incision to protect the ulnar nerve.
All half pins should have bicortical
purchase.
With the elbow concentrically re-
duced, the fixator frame is attached
to the ulna. It is useful to hold the el-
bow in flexion with the arm in the
overhead position to take advantage
of gravity to assist in concentric re-
duction and placement of the ulnar
half pins. Depending on the fixator
used, the ulnar pins are inserted ei-
ther in a dorsal-to-volar or in a
lateral-to-medial direction. After the
pins are inserted into the ulna, the
frame is secured to the ulnar pins.
With a highly unstable reduction,
the joint can be temporarily pinned
with a stout Kirschner wire before
ulnar pin insertion.
After ensuring that all the connec-
tions are secure, the axis pin is re-
moved and the elbow is taken

on the surgeon’s familiarity and
comfort with the system.
The Compass Universal Hinge
(Figure 2, A) is a multiplanar fixator
that allows incremental passive
joint ROM. The frame, which is
composed of radiolucent 1/2-in and
5/8-in rings, is assembled before ap-
plication. The humeral half pins are
placed in both medial and lateral
multiplanar positions. The ulno-
humeral articulation must be con-
centrically reduced before placing
the ulnar pins and attaching the
frame. The ulnar pins are inserted
from the dorsal surface of the ulna in
a dorsal-to-volar direction. The
frame has a self-telescoping mecha-
nism to allow a 20° arc of varus/
valgus adjustment. Distraction
screws allow joint displacement/
distraction that is independent of
the varus/valgus alignment. Addi-
tionally, a precision worm gear per-
mits motion within a specified range
and can be “ungeared” for active and
passive motion or kept locked for in-
cremental gear-driven passive mo-
tion. The patient or occupational
therapist can easily operate the gear.

Distraction control
Worm gear
Frame stability
Independent angulation
and distraction control
Passive gear-driven
motion allows for
soft-tissue
stress/relaxation
Steep learning curve
Concentric reduction
required before fixation to
ulna
Less patient comfort
More exposure needed for
medial half pins
OptiROM Elbow
Fixator
Unilateral Multiple adjustable
linkages
More patient comfort due
to unilateral design
Flexibility to allow
adjustment of frame to
elbow axis of rotation
Noninvasive technique for
axis placement
Less frame stability
No independent angulation
and distraction control

increased patient
comfort
Independent half-pin
placement
Frame stability increased
with bilateral application
Varus/valgus controlled at
pin-to-rod coupling
No passive-motion
mechanism in the frame
Concentric reduction
required before fixation to
ulna
Ulnar pin placement
impales the common
extensor muscles
Virak Tan, MD, et al
Volume 13, Number 8, December 2005 505
axis guide ring can be adjusted to lie
over the axis pin. The axis ring
should slide easily over the guide pin
for several centimeters to ensure
proper alignment of the frame with
the elbow axis of rotation. An addi-
tional benefit is that the ulnar half
pins can be inserted either from dor-
sal to volar (preferred by the authors)
or lateral to medial and locked to the
frame with the elbow in an unre-
duced position. Ulnohumeral joint

freedom. Another disadvantage is
impalement of the common exten-
sor muscles resulting from the later-
al-to-medial placement of the ulnar
pins.
The Dynamic Joint Distractor II
(Figure 2, D) is based on the same
concept as its predecessor, the
Mayo Dynamic Joint Distractor. The
Figure 2
A, Compass Universal Hinge. (Courtesy of Smith & Nephew, Memphis, TN.) B, OptiROM Elbow Fixator. (Courtesy of EBI,
Parisippany, NJ.) C, Orthofix Elbow Fixator. (Courtesy of Intavent Orthofix, Berkshire, UK.) D, Dynamic Joint Distractor II.
(Courtesy of Stryker Howmedica Osteonics, Mahwah, NJ.)
Hinged Elbow External Fixators
506 Journal of the American Academy of Orthopaedic Surgeons
frame can be applied in a unilateral
or bilateral configuration. Using a
humeral axis guide, the axis pin is
placed via open technique on the
medial side and percutaneously on
the lateral side. The guide clamps,
the center points on the medial
and lateral sides, and the axis pin
are placed through the cannulated
guide. The frame is applied over
the axis pin, and pin guides are
used to place the humeral pins.
The half pins are connected to the
frame with standard Hoffman II
Compact clamps (Stryker Howmed-

elitis can develop, in which case the
entire fixator must be removed
1,8
and intravenous antibiotics given for
6 weeks. Vigilance and local pin care
are the keys to minimizing this
complication.
Loss of reduction can occur from
improper placement of the fixator
axis or from hardware failure.
8-11
Pe-
riodic radiographic evaluation is
mandatory to confirm that the joint
remains reduced and the frame is se-
cure. With more vigorous rehabilita-
tion and motion, more stress is
placed on the components, which
can lead to pin loosening or break-
age. Pin replacement may be neces-
sary to maintain alignment between
the fixator axis and that of the el-
bow.
Despite awareness that the ulnar
nerve is at risk during surgical proce-
dures around the elbow, injury still
may occur.
7,9,12
Causes include inju-
dicious placement of the axis or me-

less commonly reported complica-
tions.
11
Using smaller diameter pins
for the ulna can help reduce the
stress riser effect. When fracture
does occur, internal fixation with
plating may be necessary. Reflex
sympathetic dystrophy also has been
reported after hinged fixation
10
and
should be treated expeditiously.
Indications
Instability
The elbow is a relatively stable
joint because of its bony anatomy
and capsuloligamentous complex.
However, disruption of these struc-
tures can render the joint unstable.
Causes of instability include disloca-
tion with medial collateral and liga-
ment tear, coronoid and radial head
fractures (the so-called terrible triad),
medial collateral ligament injury
with concomitant radial head frac-
ture, comminuted olecranon and/or
distal humerus fractures, and post-
contracture release of a stiff joint.
Ulnohumeral instability can be cat-

the terrible triad. Acute subluxation
and simple dislocation respond well
to cloned reduction followed by non-
surgical management with super-
vised rehabilitation. At the other end
of the spectrum, complex elbow dis-
location with associated radial head
and coronoid fractures and/or collat-
eral ligament disruption may render
the joint very unstable. Under these
circumstances, the radial head and
Virak Tan, MD, et al
Volume 13, Number 8, December 2005 507
coronoid should be repaired, recon-
structed, or replaced, and the collat-
eral ligament or ligaments repaired or
reconstructed. In some patients, even
with osteosynthesis and repair of the
ligaments, the elbow may still be un-
stable because of severe bony and
soft-tissue defects. With such injury
patterns, ulnohumeral instability
may not be immediately evident be-
cause the surgeon does not want to
test or stress the repair; thus, an im-
perfect or unstable reduction may
not be detected until the postopera-
tive period.
Regardless of the timing, persis-
tent instability that is present either

Chronic unreduced
dislocation
Repair or
reconstruct
ligament(s)
Total elbow
arthroplasty
Open reduction
and/or interposition
and/or ligament repair(s)
Hinged
external
fixator
Rehabilitation
program
Associated
fractures
Salvageable
No
Yes
No
Yes
YesYes
Stable range
of motion
No
No (ie, nonrigid
fracture fixation)
Stable fixation/
reconstruction

of a hinge for acute and/or recurrent
complex instability. McKee et al
10
used hinged fixation to treat com-
plex elbow instability in 16 patients.
In two patients, the fixator was ap-
plied at the time of the original treat-
ment because the elbow remained
unstable after open reduction and
internal fixation and soft-tissue re-
construction. The other 14 patients
failed conventional treatment; 11
had recurrent dislocation and 3 had
recurrent subluxation.
10
In these 14
patients, hinge application was done
at a mean of 4.8 weeks (range, 2 to
9 weeks) after the primary treat-
ment. The fixators remained in place
for a mean of 8.5 weeks (range, 6 to
11 weeks). On final follow-up 23
months after surgery (range, 14 to
40 months), 15 of 16 elbows had
achieved concentric reduction. The
mean arc of flexion-extension was
105° (range, 65° to 150°) with prona-
tion of 76° (range, 20° to 90°) and su-
pination of 75° (range, 15° to 90°). Six
patients experienced complications,

recurrent instability following frac-
ture-dislocation. Three of eight pa-
tients had acute instability and were
treated with hinge stabilization for a
mean of 43 days (range, 40 to 47
days) because of inability to achieve
complete osseous and ligamentous
repair. The average postoperative
arc of motion was 120° (range, 105°
to 130°), with average pronation of
90° and average supination of 67°.
The other five patients were treated
with an articulated fixator as an “al-
ternative to complete osseous and
ligamentous reconstruction” for re-
current instability at 6 weeks to 9
months after the initial injury.
Mean duration of external fixation
was 62 days (range, 54 to 80 days).
Their average postoperative arc of
motion was 84° (range, 75° to 95°),
with average pronation of 68° and
average supination of 43°.
In another study of a unilateral ar-
ticulating fixator, von Knoch et al
6
reported on 13 patients, 9 with acute
elbow trauma. The average duration
of external fixation was 7.6 weeks
(range, 3 to 18 weeks). These authors

and maintained by external splint-
ing. In such patients, an external fix-
ator (either static or hinged) can be
used as a primary temporizing de-
vice until definitive stabilization can
be performed.
Chronic Dislocation
Morrey
16
described two major
types of chronic elbow instability,
based on the degree of displacement:
subluxation and dislocation. Chron-
ic subluxation (ie, posterolateral ro-
tatory instability) is more common;
of these, the chronic dislocation can
be best treated with a hinged fixator.
Patients with chronic complete dis-
location of the elbow often have had
a neglected or irreducible elbow
dislocation.
17-19
Neglected disloca-
tion is more commonly seen in pa-
tients in underdeveloped countries.
However, such instances occur in
North America when the disloca-
tion is unrecognized in an unrespon-
sive multiply traumatized patient.
They also occur when the elbow re-

collateral ligaments before joint re-
duction. Because of the induced in-
stability required for the reduction, a
Kirschner wire was used to tempo-
rarily transfix the joint for 2 weeks.
Range of motion (flexion and exten-
sion) improved postoperatively. One
patient who did not have the joint
pinned redislocated. Naidoo
19
re-
ported on 23 unreduced posterior dis-
locations treated with release of the
anterior capsule and collateral liga-
ments as well as temporary trans-
fixion of the ulnohumeral joint.
Although follow-up was limited be-
cause of socioeconomic factors, use-
ful ROM was obtainable even in dis-
locations older than 3 months and in
patients older than age 40 years. Ara-
files
17
described open reduction and
an intra-articular “cruciate” liga-
ment reconstruction with a free
tendon graft in 11 patients with ne-
glected elbow dislocation. This pro-
cedure was devised to allow early el-
bow motion in the flexion-extension

The elbow joint was exposed both
medially and laterally, but the origin
of the flexor-pronator mass was left
attached to the medial epicondyle.
Adhesions and the entire lateral cap-
sule were resected, after which the
ulnohumeral joint was reduced and
the hinged fixator applied. At an av-
erage of 38 months (range, 12 to 98
months), all patients had stable con-
centric reduction and a satisfactory
Mayo Elbow Performance Index (av-
erage score, 89 points). The average
arc of flexion was 123°, and all pa-
tients had full forearm rotation.
In cases of chronic unreduced el-
bow dislocation, a hinge-distraction
device can be useful to maintain ul-
nohumeral joint reduction without
transfixing the joint and to start im-
mediate concentric motion. A hinge-
distraction device also allows the
joint to unload by distraction and
the soft-tissue sleeves to heal in the
optimal position for motion.
Distraction Interposition
Arthroplasty
Distraction interposition arthro-
plasty has been developed from two
procedures—distraction and biolog-

success in the elbow.
21-24
This proce-
dure has been used for posttraumatic
or postinfectious ankylosis, hemo-
philic arthropathy, and rheumatoid
arthritis.
21-24
In 1952, Knight and Van
Zandt
24
reported the results of fascia
lata interposition arthroplasty in 45
patients with partial or complete
elbow ankylosis. At an average
follow-up of 14 years, there were 25
good, 10 fair, and 10 poor or failed el-
bows. In 1976, Froimson et al
23
re-
ported satisfactory results using deep
dermal skin interposition arthro-
plasty in five patients. However, two
patients had varus-valgus instability
of 20° and 30°, respectively. Ljung et
al
22
found that the results of interpo-
sition arthroplasty in 35 rheumatoid
elbows were good in terms of pain re-

lateral column and/or medial over-
the-top approach.
26
After the release,
if visual inspection of the joint sur-
face reveals loss of articular cartilage
Hinged Elbow External Fixators
510 Journal of the American Academy of Orthopaedic Surgeons
≥50%, significant intra-ar ticular ad-
hesions causing avulsion of cartilage
during motion, or an intra-articular
malunion requiring recontouring,
then interposition arthroplasty
should be performed.
8
The lateral
ligament complex is sharply divided
from the humerus. If necessary for
exposure, the triceps is mobilized as
a continuous sleeve from the ulna.
Manual distraction applied across
the ulnohumeral articulation often
provides sufficient exposure to per-
form the operation without remov-
ing the triceps insertion. The ulno-
humeral joint surfaces are then
prepared by contouring them into
matching surfaces. Bone resection
should be sufficient to allow a gap of
at least 3 mm. The radial head is re-

of these results are embedded with-
in larger study cohorts. Although the
results are not as reproducible as for
patients undergoing total elbow ar-
throplasty, most patients have im-
provement in ROM and moderate to
significant pain relief.
Distraction interposition arthro-
plasty likely will become more com-
mon as the number of patients with
posttraumatic elbow arthropathy in-
creases. This procedure is indicated
for patients with intra-articular pa-
thology who are too young for a total
elbow prosthesis. It also is indicated
in certain patients with inflammatory
arthropathy , and in patients who have
experienced trauma or infection.
Postoperative Control of
Motion
Elbow contracture releases, espe-
cially revision cases, often require
extensive excision of soft tissues and
bone structures to regain motion.
These structures include the collat-
eral ligaments, heterotopic bone, os-
teophytes, and the hypertrophic cap-
sule. Because the goal of surgery is to
improve elbow motion, the surgeon
should not abandon this goal until

Patients
Mean
Follow-up
(months)
Mean Preoperative
Flexion-Extension Arc
(range)
Mean Postoperative
Flexion-Extension Arc
(range) Results
Morrey
8
6 33 27° (0°-60°) 107° (70°-150°) —
Morrey
4
20 — — — 80% satisfactory
Cobb and
Morrey
11
2 30 38° (35°-40°) 84° (57°-110°) Both satisfactory
Cheng and
Morrey
25
13* 63 60° (24°-100°) 84° (40°-135°) 69% satisfactory
pain relief, 62%
excellent or good
result
Pignatti et al
9
12 Range, 8-33 35° (0°-90°) 91° (—) 92% satisfied with

and how to apply the fixator. An un-
derstanding of the anatomy, specific
technique, and indications for each
problem is crucial for restoring el-
bow function. Current indications
include acute and recurrent instabil-
ity after osteosynthesis and ligament
repair, chronic dislocation, distrac-
tion interposition arthroplasty, and
postoperative control of motion.
Hinged external fixation is also indi-
cated in the uncommon case of
acute elbow instability when con-
centric reduction cannot be achieved
by splinting or in a patient who can-
not tolerate a prolonged intraopera-
tive surgical procedure. The two
main types of hinged elbow fixators
are unilateral and multiplanar. Uni-
lateral frames inflict less ulnar nerve
irritation, have a lower profile, and
Figure 4
A 15-year-old girl sustained a fracture-dislocation of the elbow in a fall from a horse. A, Lateral radiograph demonstrating
complete ankylosis of the ulnohumeral joint, fixed at 75°. B, Intraoperative photograph demonstrating takedown of the bony
ankylosis and distraction interposition arthroplasty 4 years after injury. Postoperative anteroposterior (C) and lateral (D)
radiographs demonstrating the new elbow articulations.
Hinged Elbow External Fixators
512 Journal of the American Academy of Orthopaedic Surgeons
are relatively easy to apply. Multi-
planar fixators provide more rigid

6. von Knoch F, Marsh JL, Steyers C,
McKinley T, O’Rourke M, Bottlang
M: A new articulated elbow external
fixation technique for difficult elbow
trauma. Iowa Orthop J 2001;21:13-
19.
7. Fox RJ, Varitimidis SE, Plakseychuk
A, Vardakas DG, Tomaino MM, So-
tereanos DG: The Compass Elbow
Hinge: Indications and initial results.
J Hand Surg [Br] 2000;25:568-572.
8. Morrey BF: Post-traumatic contrac-
ture of the elbow: Operative treat-
ment, including distraction arthro-
plasty. J Bone Joint Surg Am 1990;72:
601-618.
9. Pignatti G, Ferrari D, Tigani D, et al:
The treatment of post-traumatic stiff-
ness of the elbow. Chir Organi Mov
2000;85:381-387.
10. McKee MD, Bowden SH, King GJ, et
al: Management of recurrent, com-
plex instability of the elbow with a
hinged external fixator. J Bone Joint
Surg Br 1998;80:1031-1036.
11. Cobb TK, Morrey BF: Use of distrac-
tion arthroplasty in unstable fracture
dislocations of the elbow. Clin
Orthop Relat Res 1995;312:201-210.
12. Ruch DS, Triepel CR: Hinged elbow

19. Naidoo KS: Unreduced posterior dis-
locations of the elbow. J Bone Joint
Surg Br 1982;64:603-606.
Figure 5
Same patient as in Figure 4. At 1 year postoperatively, the patient had a stable
elbow, with active elbow motion from 35° (A) to 125° (B), forearm supination of
45° (C), and pronation of 65° (D). Although there was mild crepitus with motion, the
patient experienced only occasional discomfort.
Virak Tan, MD, et al
Volume 13, Number 8, December 2005 513
20. Jupiter JB, Ring D: Treatment of unre-
duced elbow dislocations with hinged
external fixation. J Bone Joint Surg
Am 2002;84:1630-1635.
21. Dickson RA, Stein H, Bentley G: Exci-
sion ar throplasty of the elbow in rheu-
matoid disease. J Bone Joint Surg Br
1976;58:227-229.
22. Ljung P, Jonsson K, Larsson K, Ryd-
holm U: Interposition arthroplasty of
the elbow with rheumatoid arthritis.
J Shoulder Elbow Surg 1996;5(2 pt 1):
81-85.
23. Froimson AI, Silva JE, Richey D: Cu-
tis arthroplasty of the elbow joint.
J Bone Joint Surg Am 1976;58:863-
865.
24. Knight RA, Van Zandt IL: Ar throplas-
ty of the elbow: An end-result study.
J Bone Joint Surg Am 1952;34:610-