CLINICAL ORTHOPAEDICS AND RELATED RESEARCH
Number 391, pp. 251–257
© 2001 Lippincott Williams & Wilkins, Inc.
Bilateral Humeral Lengthening
in Achondroplasia
Naoya Kashiwagi, MD; Shigeo Suzuki, MD, PhD; Yoichi Seto, MD;
and Tohru Futami, MD
Twenty humeral lengthenings were done on 10
achondroplastic dwarfs using the Ilizarov circular fixator. There were five female and five male
patients from 6 years 11 months to 17 years 8
months of age (mean, 12 years 10 months) at the
time of the operation. Mean length obtained was
7.8 cm (range, 3.5 cm–10 cm). External fixation
time ranged from 105 days to 368 days (mean,
221 days). Healing index averaged 30 days/cm
(27 days/cm when two patients with radial nerve
palsy were excluded). Two half pins in one patient required replacement. Two humeral fractures occurred, one while in the fixator and the
other after removal of the apparatus. Transient
radial nerve palsy developed during lengthening
in two patients, and lengthening was discontinued. Symptoms of radial nerve palsy resolved
completely in both patients, but one patient required an additional surgery to explore the radial nerve for persistent paresthesia of the forearm. Although preexisting loose shoulders
deteriorate during lengthening and sometimes
cause pain and discomfort, they always resolve
spontaneously as lengthening proceeds. Bilateral humeral lengthening was very effective for
improving function and overall proportion in
patients with achondroplasia.
Achondroplasia is a short-limb dwarfism with
rhizomelic involvement. Lengthening of lower
limbs is the accepted treatment for their short
stature. However, only limited numbers of reports are available on bilateral humeral lengthening in rhizomelic dwarfism.1,2,5 In patients
with achondroplasia, the upper arms are disproportionally short compared with the forearms, leading to functional, cosmetic, and psychologic problems.
This article describes the authors’ method
for humeral lengthening and presents the clinical outcome and complications that occurred,
with special emphasis on radial nerve palsy
and inferior subluxation of the shoulder.
MATERIALS AND METHODS
Lengthening of 20 humeri was done in nine patients with achondroplasia and one patient with
hypochondroplasia between 1996 and 1999 (Table
1). All of the patients already had undergone bilateral tibial lengthening, and five also had bilateral
femoral lengthening before undergoing humeral
lengthening. The five male and five female patients
ranged in age at the time of surgery from 6 years 11
months to 17 years 8 months (mean, 12 years 10
months). The average followup after surgery was
2.8 years (range, 1.5–4.2 years).
The fixator configuration for humeral lengthen-
From the Department of Orthopaedic Surgery, Shiga
Medical Center for Children, Shiga, Japan.
Reprint requests to Naoya Kashiwagi, MD, Shiga Medical Center for Children, 5-7-30 Moriyama, Moriyamacity, Shiga, 524-0022, Japan.
Received: December 12, 2000.
Revised: March 7, 2001.
Accepted: April 27, 2001.
251
8 years 4 months
17 years 5 months
6 years 11 months
17 years 6 months
12 years 5 months
12 years 9 months
17 years 8 months
16 years 10 months
9 years 7 months
2
3
4
5
6
7
8
9
10
F
F
F
F
F
M
M
M
M
M
ACH
ACH
ACH
ACH
ACH
ACH
HYPO
ACH
ACH
ACH
Gender Etiology
Proximal
Proximal
Proximal
Proximal
Proximal
Distal
Distal
Distal
Proximal
Distal
Site
of
Corticotomy
ACH achondroplasia; HYPO hypochondroplasia; M male; F female.
9 years 3 months
Age
Patient Data
1
Patient
TABLE 1.
8.0
8.5
10.0
10.0
10.0
8.0
3.5
3.8
8.0
8.5
Length
Achieved
(cm)
52.9
54.3
66.5
63.8
59.6
59.0
13.5
23.2
44.7
63.5
Increase
in
Length
(%)
180
368
238
203
238
154
205
105
294
224
Duration
of External
Fixation
(days)
22.5
43.3
23.8
20.3
23.8
19.3
58.6
27.6
36.8
26.4
Healing
Index
(days/cm)
Fracture after frame
removal
Radial nerve palsy
Radial nerve palsy
Broken half
pinfracture,
varus angulation
Shoulder
subluxation
Breakage of two
half pins
Problems
Number 391
October, 2001
ing consists of two rings; one omega-shaped ring
proximally, and one 5⁄8 ring distally, according to
the method described by Cattaneo et al.1 For distal
fixation, two wires with one half pin or one wire
with two half pins are used. Two half pins are used
for proximal fixation, and no wires are used proximally to avoid the risk for damaging the neurovascular structures. Of the two proximal half pins, one
is inserted just lateral to the long head of the biceps
brachii, and the other is inserted just proximal to the
deltoid insertion. Corticotomy was done distal to
the groove of the radial nerve in the earlier cases
(Patients 1–4), but in the recent cases (Patients
5–10), corticotomy was done proximally at the
level of the deltoid insertion through an anterolateral incisions. Distraction is begun at a rate of 0.25
mm four times a day, 5 to 7 days after surgery.
When signs or symptoms of neurapraxia (paresthesia or drop hand) are seen during lengthening, the
rate of lengthening is stopped or decreased. During
lengthening, vigorous physiotherapy is encouraged
for shoulders, elbows, and hands. The goal of
lengthening is 8.0 cm or more, as suggested by Cattaneo et al.1 After three intact cortices have been
seen (of four cortices) on the anteroposterior (AP)
and lateral radiographs, the fixator is removed with
the patient under general anesthesia. No external
protection is used thereafter. Patients’ satisfaction
was assessed by the interview with the patients and
their parents. Criteria for functional evaluation
originally used by Cattaneo et al1 and modified by
the current authors were used. A grade of excellent
was given if the patient had improvement over preoperative function. A good result required the
preservation of preoperative function. The results
were graded as poor if there was some diminution
of function, a significant decrease in joint range of
motion (ROM), or permanent neurologic injury.
Range of motion of the elbow was documented before surgery, at the end of lengthening, immediately after fixator removal, and at final followup.
Inferior subluxation of the shoulder was assessed
using standing radiographs. Symptoms presumed
to result from shoulder subluxation were checked
from the clinical chart.
RESULTS
Patient Satisfaction
Eight patients without radial nerve palsy were
satisfied with the results functionally and cosmetically. The patient with hypochondropla-
Bilateral Humeral Lengthening
253
sia (Patient 3) had radial nerve palsy and
gained only 3.5 cm in humeral length. However, he is satisfied with the result because his
preoperative arm length was not as short as
seen in some patients with achondroplasia,
and despite the small gain of length, he is able
to wear regular clothes. The parents of the
other patient with radial nerve palsy (Patient
4) are not satisfied with the amount of lengthening and hope for additional lengthening.
Functional Outcome
All but two patients gained 8.0 cm or more in
length. In two patients (Patients 3, 4) who had
unilateral temporary radial nerve palsy,
lengthening was stopped and the gain in
humeral length only was 3.5 cm and 3.8 cm,
respectively. Except for Patient 5, who had
residual varus deformity of the left humerus
(described below), neither angular nor rotational deformity occurred with lengthening.
The results in eight of 10 patients were graded
as excellent, meaning that the patients achieved
functional improvement. After surgery, most
of the patients gained the ability to deal with
perineal hygiene, to reach above the head, and
to pull pants and socks on and off. It has become much easier for them to wash their face
or brush their teeth. In addition, the patients
who had extensive humeral lengthening could
transfer to the wheelchair more easily because
of the improved ability to push up. Two patients (Patients 3, 4) who had no functional
improvement were graded as having good
results.
Amount of Lengthening, External Fixation
Time, and Healing Index
The mean length obtained was 7.8 cm (range,
3.5 cm–10 cm), which was a 50% increase of
the original bone length. External fixation
ranged from 105 days to 368 days (mean, 221
days). The healing index averaged 30
days/cm. When two patients with radial nerve
palsy were excluded, the mean amount of
lengthening (% increase), external fixation
time, and healing index were 8.9 cm (58%),
237 days, and 27 days/cm, respectively.
254
Kashiwagi et al
Range of Motion of the Elbow
Some patients lost some ROM of their elbow
during lengthening, but every patient had regained preoperative range of elbow motion at
the final followup (Fig 1). Because of poor
compliance for physiotherapy in Patient 10,
flexion contracture of both elbows progressed,
even after cessation of lengthening. The ROM
of the patient’s right and left elbows was limited to 75 to 110 and 80 to 110 (29% and
25% of preoperative total arc, respectively)
immediately after removal of the frame. This
patient fractured her right humerus 4 days after removal of the fixator.
Breakage of Half Pins and Fracture
Two half pins in one patient broke during
lengthening, which required pin replacement.
In this patient, the half pins of 4 mm in diameter were too small for the patient’s bone and
were replaced by pins that were 5 mm in diameter. In the left upper arm of Patient 5, one
proximal half pin (5 mm in diameter) broke,
and a fracture occurred through the distraction
callus when he fell. Because the distracted callus had reached near maturity and the fracture
was considered to be stable in the fixator, nothing was done about the pin or for the fracture.
The fracture consolidated uneventfully by the
time the fixator was removed. The patient’s left
Clinical Orthopaedics
and Related Research
humerus had residual varus angulation of 14,
but no functional diminution was seen because
of this deformity. Another fracture occurred in
the right humerus of Patient 10 from the junction of the regenerate and the original bone extending through the supracondylar region. This
fracture occurred 4 days after removal of the
fixator when the patient tried to push up. This
nondisplaced spiral fracture healed uneventfully with the use of an arm sling.
Radial Nerve Palsy
Transient radial nerve palsy occurred during
lengthening in two patients (Patients 3, 4). Patient 3 noticed numbness in his left forearm and
weakness of extension power in his left wrist
and fingers on the forthy-third day after surgery,
when the humerus had gained 3.7 cm in length.
At that time, lengthening was discontinued and
acute shortening was done by 2 mm. In less than
1 month, his motor paralysis resolved. However, tingling and numbness persisted in his left
forearm, and the radial nerve was explored 7
months after fixator removal. The operative
finding revealed radial nerve entrapment between tightened fascia of the medial head of triceps brachii and brachialis muscle. Complete
release of the tight fascia resulted in relief of his
symptoms. Patient 4 had numbness in his left
middle finger on the thirty-eighth day after
Fig 1. The degree of maximum flexion of each elbow is
marked as a black dot (•), and
maximum extension as an asterisk (*). Open square and bar
indicate mean value standard deviation.
Number 391
October, 2001
Bilateral Humeral Lengthening
surgery, and the rate of lengthening was slowed
to 0.5 mm/day. On the sixty-fourth day, when
two rings were distracted 4.6 cm apart, the patient fell and felt sudden pain in his left upper
arm. The patient was unable to actively dorsiflex
his left wrist. A radiograph of the upper arm
showed a humeral fracture with an 8-mm gap,
which was considered to have occurred in a prematurely consolidated callus, resulting in sudden stretching through the soft tissues. At that
time, acute shortening of 8 mm was done. The
patient recovered from the motor paralysis in
less than 1 month with no residual symptoms.
Inferior Subluxation of the
Glenohumeral Joint
In Patient 6, inferior subluxation of the shoulder was not evident from preoperative standing
radiographs. Two days after lengthening, the
patient reported dull pain extending from her
left shoulder to the forearm. Anteroposterior ra-
A
B
255
diographs revealed an inferiorly subluxated
humeral head on the left side. Her symptoms
decreased with the use of an elbow sling and
physiotherapy with isometric exercises,6 and
the patient’s lengthening was continued at the
same rate. As lengthening proceeded, the patient’s symptoms resolved, and the serial standing radiographs showed a gradually reduced
left glenohumeral joint (Fig 2). The physicians
were encouraged by this experience, and
humeral lengthening was done for three other
patients (Patients 7–9) who had apparent shoulder instability shown by preoperative standing
radiographs. One of these three patients felt
temporary pain around her arms during lengthening, which subsided with conservative treatment. The other two patients had no symptoms
throughout the lengthening. In these three patients, the shoulders also were reduced gradually along with progression of lengthening (Fig
3). Anatomically reduced glenohumeral joints
C
Fig 2A–C. (A) A preoperative standing radiograph of Patient 6 shows no apparent shoulder subluxation. (B) Inferior subluxation of the glenohumeral joint is evident shortly after the start of lengthening.
(C) The shoulder gradually became stabilized during lengthening, and this reduction has been maintained at 2.2 years’ followup after removal of the frame.
256
Clinical Orthopaedics
and Related Research
Kashiwagi et al
in these four patients have been maintained at a
mean followup of 1.6 years (range, 1–2.2 years)
after removal of the fixator.
DISCUSSION
In achondroplastic dwarfs, a rhizomelic pattern is more prominent in the upper extremities, with the upper arms being disproportionally short compared with the forearms. This
results not only in functional deficits, such as
reaching height or inability to deal with perineal hygiene, but also in an aesthetic problem,
especially when the lower extremities have
been lengthened extensively.1,5
By using Ilizarov’s principle of distraction
histogenesis, significant length can be achieved
with minimal risks.2 Half pins are used instead
of wires for proximal fixation to minimize the
potential risk for nerve injury. In the current series, no neurologic deficits were seen during the
immediate postoperative period.
By having both upper arms lengthened, the
patients gain access to their perineal region
A
more easily without twisting their spine. This
has improved their perineal hygiene significantly. In addition, the ability to push themselves up with their arms has improved after
humeral lengthening. This ability to push up
facilitates transfer to a wheelchair, which is
important when both femurs are being lengthened. Thus, humeral lengthening is recommended, particularly for patients who have
difficulty with push up before bilateral femoral lengthening. Some patients lose their ability to pull their pants or socks on and off after
extensive lower limb lengthening. In these patients, humeral lengthening also was essential
to regaining their lost function.
Breakage of half pins can be avoided by selecting pins of the appropriate size. Half pins
that are 6 mm in diameter are used routinely,
except when the width of the humeral bone is
less than 18 mm. Only one fracture occurred
after removal of the fixator. This spiral fracture extended from the junction of the regenerate and the original bone through the distal
supracondylar region. Simpson and Ken-
B
Fig 3A–B. (A) A preoperative standing radiograph of Patient 7 shows an inferiorly subluxated shoulder. (B) The shoulder gradually became stabilized during lengthening, and this reduction has been
maintained at 2 years’ followup after removal of the frame.
Number 391
October, 2001
wright3 reported that the junctional fracture in
the femur was associated with loss of movement of the knee. The current patient had decreased ROM of the elbow when the fixator
was removed, and this is thought to cause a
large bending moment. This emphasizes the
importance of efforts to regain elbow movement before removal of the frame.
During lengthening, radial nerve palsy developed in two limbs in two patients. In one patient, it was caused by sudden stretching of the
nerve because of fracture of the prematurely
consolidated distraction callus; this may be
avoided by paying special attention to the premature consolidation, especially when the rate
of lengthening is slowed. In the other patient,
subsequent exploration disclosed the radial
nerve entrapment by the tightened fascia of the
medial head of the triceps brachii, and release
of this entrapment has significantly reduced the
patient’s symptoms. The entrapment probably
can be avoided by lengthening through the deltoid tuberosity, which lies proximal to the origin of the medial head of the triceps brachii.
Twelve humeri in six patients were lengthened
proximally at this level, and they all gained satisfactory length with no neurologic deficits.
Based on the authors’ experience, the preferred
site for corticotomy is considered to be proximal, rather than distal.
Inferior subluxation of the glenohumeral
joint sometimes is associated with patients with
achondroplasia. The exact mechanism for this
subluxation has not been described in the literature. The influence of humeral lengthening on
unstable shoulders also has not been reported
previously. It has been reported that acetabular
dysplasia precludes femoral lengthening because of the risk of hip dislocation.4 From the
current authors’ experience, a stable shoulder is
not necessarily a prerequisite for lengthening
the humerus. However, unstable (subluxated)
joints gradually became stabilized as lengthening proceeded, and this beneficial effect did not
seem to deteriorate with time in all four patients. Thus, unstable joints are the recommended indication for humeral lengthening. Inferior subluxation during early lengthening can
be treated conservatively with an elbow sling
Bilateral Humeral Lengthening
257
and early physiotherapy.6 A specially designed
shoulder sling is used that suspends the bilateral
Ilizarov ring to minimize discomfort in this period. The mechanism of shoulder reduction
throughout the lengthening procedure needs
consideration. In patients with achondroplasia,
abnormal growth cartilage results in short tubular bones leaving the soft tissue relatively intact. This may cause length disproportion of the
bone and its surrounding soft tissues. With
humeral lengthening, this disproportion is eliminated, and muscles across the shoulder become
tightened and activated.
Bilateral humeral lengthening in achondroplastic dwarfs is a safe and effective means
of improving function and cosmesis. Lengthening of both humeri simultaneously does not
result in functional problems during treatment. The patients can go to school and have
little disturbance of activity of daily life while
wearing fixators. Humeral lengthening can be
done even when the patient is skeletally immature, provided that the patient is old enough
to comply with physiotherapy. At the time of
the operation, appropriate pin size should be
selected and corticotomy should be done
through the level of the deltoid tuberosity.
Range of motion of the elbow should be regained by the time the fixator is removed. One
should look for symptoms indicative of radial
nerve palsy during lengthening. Preexisting
shoulder instability does not preclude humeral
lengthening.
References
1. Cattaneo R, Villa A, Catagni MA, et al: Lengthening
of the humerus using the Ilizarov technique. Clin Orthop 250:117–124, 1990.
2. Ilizarov GA: Clinical application of the tensionstress effect for limb lengthening. Clin Orthop
250:8–26, 1990.
3. Simpson AHRW, Kenwright J: Fracture after distraction osteogenesis. J Bone Joint Surg 82B:659–
665, 2000.
4. Suzuki S, Kasahara Y, Seto Y, et al: Dislocation and
subluxation during femoral lengthening. J Pediatr
Orthop 14:343–346, 1994.
5. Tetsworth K, Krome J, Paley D: Lengthening and
deformity correction of the upper extremity by the
Ilizarov technique. Orthop Clin North Am 22:
689–713, 1991.
6. Yosipovitch Z, Tikva P, Goldberg I: Inferior subluxation of the humeral head after injury to the shoulder.
J Bone Joint Surg 71A:751–753, 1989.