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Vol 7, No 3, May/June 1999
199
Once thought to be an uncommon
injury, distal biceps tendon rup-
tures are being seen with increas-
ing frequency. A few early reports
describe satisfactory results with
nonoperative treatment
1,2
or non-
anatomic repair.
3
However, biome-
chanical studies and clinical reports
highlighting the role of the biceps
muscle in elbow function have
raised questions about the success
of these methods.
4-8
Today, most
would agree that anatomic repair
to the radial tuberosity is necessary
to obtain strength and endurance
in supination and flexion.
Anatomy
The biceps muscle is the most
superficial muscle in the anterior
compartment of the arm. The dis-
tal tendon of the biceps muscle
passes deep in the antecubital fossa
to insert at the radial tuberosity.

The bicipital aponeurosis (lacertus
fibrosus) arises from the medial
aspect of the muscle belly at the
junction of the musculotendinous
unit and the distal biceps tendon.
It passes distally and medially
across the antecubital fossa, blend-
ing with the fascia overlying the
proximal flexor mass of the fore-
arm, and inserts on the subcuta-
neous border of the ulna.
An appreciation of the local neuro-
vascular anatomy is critical if
injury to these structures is to be
avoided at the time of surgical
repair. The lateral antebrachial
cutaneous nerve is the terminal
cutaneous branch of the musculo-
cutaneous nerve, which supplies
sensation to the volar-lateral aspect
of the forearm. This nerve pierces
the deep fascia of the arm near the
musculotendinous junction of the
distal biceps tendon between the
biceps and brachialis muscles. It
exits the arm and lies in the subcu-
taneous tissues of the antecubital
fossa.
Dr. Ramsey is Assistant Professor of Ortho-
paedic Surgery, University of Pennsylvania

School of Medicine, Penn Musculoskeletal
Institute, Presbyterian Medical Center,
Philadelphia.
Reprint requests: Dr. Ramsey, Penn Musculo-
skeletal Institute, Presbyterian Medical Center,
One Cupp Pavilion, 39th and Market Street,
Philadelphia, PA 19104.
Copyright 1999 by the American Academy of
Orthopaedic Surgeons.
Abstract
Rupture of the distal biceps tendon occurs most commonly in the dominant
extremity of men between 40 and 60 years of age when an unexpected extension
force is applied to the flexed arm. Although previously thought to be an uncom-
mon injury, distal biceps tendon ruptures are being reported with increasing
frequency. The rupture typically occurs at the tendon insertion into the radial
tuberosity in an area of preexisting tendon degeneration. The diagnosis is made
on the basis of a history of a painful, tearing sensation in the antecubital region.
Physical examination demonstrates a palpable and visible deformity of the distal
biceps muscle belly with weakness in flexion and supination. The ability to pal-
pate the tendon in the antecubital fossa may indicate partial tearing of the
biceps tendon. Plain radiographs may show hypertrophic bone formation at the
radial tuberosity. Magnetic resonance imaging is generally not required to
diagnose a complete rupture but may be useful in the case of a partial rupture.
Early surgical reattachment to the radial tuberosity is recommended for optimal
results. A modified two-incision technique is the most widely used method of
repair, but anterior single-incision techniques may be equally effective provided
the radial nerve is protected. The patient with a chronic rupture may benefit
from surgical reattachment, but proximal retraction and scarring of the muscle
belly can make tendon mobilization difficult, and inadequate length of the distal
biceps tendon may necessitate tendon augmentation. Postoperative rehabilita-

tion must emphasize protected return of motion for the first 8 weeks after repair.
Formal strengthening may begin as early as 8 weeks, with a return to unre-
stricted activities, including lifting, by 5 months.
J Am Acad Orthop Surg 1999;7:199-207
Distal Biceps Tendon Injuries:
Diagnosis and Management
Matthew L. Ramsey, MD
The median nerve, brachial
artery, and brachial vein lie medial
to the biceps tendon beneath the
bicipital aponeurosis. The brachial
artery bifurcates at the level of the ra-
dial head into its terminal branches,
the radial and ulnar arteries. The
radial recurrent artery branches
from the radial artery and passes
laterally and proximally across the
antecubital fossa.
The radial nerve enters the ante-
cubital fossa laterally between the
brachialis and brachioradialis mus-
cles. Anterior to the humeral epi-
condyle, the nerve divides into a
superficial branch and a deep
branch. The superficial branch of
the radial nerve continues into the
forearm under the brachioradialis
and lateral to the radial artery and
supplies sensation to the middorsal
aspect of the forearm. The deep

branch of the radial nerve (posterior
interosseous nerve) courses around
the lateral side of the radius and
enters the supinator muscle be-
tween its humeral and radial heads.
Functional Biomechanics
The biceps muscle is the strongest
supinator of the forearm and assists
the brachialis in elbow flexion. The
ability of the biceps to perform
these functions depends on the
position of the arm. The biceps
muscle is more active in flexion of
the supinated forearm than in flex-
ion of the pronated forearm. There
is little, if any, electrical activity in
the biceps muscle when flexion of
the pronated forearm is attempted,
unless there is a substantial pronat-
ing force resisting supination.
9
Contraction of the biceps muscle
tends to supinate the pronated fore-
arm and may therefore be inhibited
when the forearm is in pronation.
The contribution of the biceps to
forearm supination increases with
elbow flexion, reaching a maximum
at about 90 degrees of flexion.
Beyond 90 degrees, there is no sub-

stantial increase in biceps activity as
the muscle-tendon unit shortens.
10
Etiology
Rupture of the distal biceps tendon
is most likely to occur in the domi-
nant extremity of men between the
fourth and sixth decades of life. The
average age at the time of rupture is
approximately 50 years (range, 18
to 72 years).
3,5-7,11-18
All reported
cases of complete distal biceps ten-
don rupture have occurred in men.
However, partial rupture of the dis-
tal biceps tendon has been reported
in women.
19
The mechanism of injury is usu-
ally a single traumatic event in
which an unexpected extension
force is applied to an arm flexed to
90 degrees. The tendon typically
avulses from the radial tuberosity,
although ruptures within the ten-
don substance and at the musculo-
tendinous junction have been
reported. The bicipital aponeurosis
may or may not rupture acutely.

Some authors have described the
rupture as occurring in stages, such
that the insertion to the radial
tuberosity is disrupted initially and
the bicipital aponeurosis tears later,
completing the rupture.
19,20
How-
ever, the bicipital aponeurosis may
be intact in some instances, pre-
venting proximal migration of the
ruptured tendon into the arm.
The pathogenesis of distal biceps
tendon ruptures is poorly under-
stood. Degenerative and mechani-
cal processes have been implicated
as the cause of rupture. It is gener-
ally accepted that normal tendons
do not rupture.
18,21,22
The contribu-
tion of a degenerative process to
tendon rupture is supported by
intraoperative observations of a
thickened, bulbous distal end of the
tendon. Microscopic characteriza-
tion of spontaneously ruptured ten-
dons, including the distal biceps
tendon, has demonstrated an array
of degenerative changes.

21
Interest-
ingly, similar changes were present
in control specimens from patients
with no history of symptoms relat-
ed to the distal biceps tendon. The
degenerative process may continue
unrecognized, compromising the
structural integrity of the tendon,
until sufficient trauma causes com-
plete rupture.
Hypovascularity of the tendon
may play a role in tendon rupture
in some patients. Vascular injection
studies of the distal biceps tendon
demonstrate two consistent sources
of extratendinous blood supply,
one distally at the tendon insertion
from the posterior recurrent artery
and one proximally from the
brachial artery. A hypovascular
zone has been identified between
the proximal and distal zones.
23
The fact that most ruptures occur at
the tendon insertion, as opposed to
a more proximal location, would
seem to eliminate hypovascularity
as the sole cause of rupture.
The space available for the bi-

ceps tendon between the radius
and the ulna changes depending on
forearm position. The distance
between the radius and the ulna is
maximal in supination and de-
creases progressively with forearm
pronation. In full pronation, the bi-
ceps tendon occupies 85% of the
available space
23
; therefore, any-
thing that encroaches on this space
may result in mechanical impinge-
ment. Davis and Yassine
22
theo-
rized that hypertrophic bone on the
anterior margin of the radial tuber-
osity contributes to tendon failure
because of repetitive impingement
with forearm rotation.
Clinical Evaluation
History and Physical
Examination
Patients with complete distal
biceps tendon ruptures usually
Distal Biceps Tendon Injuries
Journal of the American Academy of Orthopaedic Surgeons
200
report an unexpected extension

force applied to the flexed arm.
The most common symptom asso-
ciated with distal biceps tendon
rupture is a sudden, sharp, painful
tearing sensation in the antecubital
region of the elbow and occasional-
ly in the posterolateral aspect of the
elbow. The intense pain subsides
in a few hours and is replaced by a
dull ache, which can last for weeks
and may become chronic activity-
related pain. Subjective weakness
in supination is a variable com-
plaint, which may depend on the
functional demands placed on the
extremity. Weakness in flexion is
profound immediately after rup-
ture because of pain but tends to
diminish with time.
Physical examination demon-
strates tenderness in the antecu-
bital fossa. A defect in the antecu-
bital fossa can usually be palpated.
If the biceps tendon is palpated in
the antecubital fossa, a partial rup-
ture of the distal biceps tendon
must be considered. If the bicipital
aponeurosis is intact, the deformity
is not as pronounced but is usually
easy to appreciate on comparison

with the opposite extremity. With
active flexion of the elbow, the
biceps muscle belly retracts proxi-
mally, accentuating the defect in
the antecubital fossa (Fig. 1).
Ecchymosis and swelling appear in
the antecubital fossa and along the
medial aspect of the arm and proxi-
mal forearm.
Weakness in supination, as well
as some weakness in flexion, can
usually be demonstrated. In the
acute phase, weakness may be
related to pain in addition to the
functional deficits of the detached
biceps tendon.
Radiologic Evaluation
Radiographic studies can aid in
the diagnosis of ruptures of the dis-
tal biceps tendon but are not a sub-
stitute for a thorough history and
physical examination. Plain radio-
graphs generally do not demon-
strate any osseous changes. How-
ever, irregularity and enlargement
of the radial tuberosity
22
and avul-
sion of a portion of the radial
tuberosity

3
have been reported in
patients with complete ruptures of
the distal biceps tendon.
Inability to palpate the distal
biceps tendon in the antecubital
fossa is indicative of a complete
rupture. If the history and symp-
toms suggest a biceps tendon
injury and the tendon can be pal-
pated in the antecubital fossa, other
causes of antecubital pain, includ-
ing cubital bursitis, bicipital tendi-
nosis (tendon degeneration), partial
biceps tendon rupture, and entrap-
ment of the lateral antebrachial
cutaneous nerve, must be investi-
gated. Cubital bursitis (enlargement
of the bursal sac that lies between
the biceps tendon and the anterior
aspect of the radial tuberosity) may
exist in isolation or in association
with a distal biceps tendon lesion.
Tendon degeneration (bicipital
tendinosis) without rupture may
occur in isolation or in association
with cubital bursitis or partial rup-
ture. In this circumstance, magnet-
ic resonance (MR) imaging of the
elbow may provide useful informa-

tion about the integrity of the distal
biceps tendon and any intrasub-
stance degeneration (Fig. 2). How-
ever, the distinction between bicip-
ital tendinosis and partial ruptures
is not always apparent on MR
imaging.
24
Classification
There is no widely accepted classi-
fication for distal biceps tendon
injuries. Partial ruptures of the dis-
tal biceps tendon have been report-
ed only in case reports and small
series.
19,24,25
Partial tendon failure
can occur at the tendon insertion to
bone
19,22,24
or within the substance
of the tendon, which can be elon-
gated.
25
Because so few cases of
partial rupture have been reported,
any classification that aspires to
guide treatment is subject to error.
Complete ruptures are arbitrar-
ily classified on the basis of the

amount of time between rupture
and diagnosis. In chronic tears, the
integrity of the bicipital aponeuro-
sis is also important because of its
role as a tether to proximal retrac-
tion. The value of defining the
chronicity of the rupture and the
integrity of the bicipital aponeuro-
sis lies in its usefulness in predict-
ing the ease of repair (Table 1).
Distal biceps tendon ruptures
diagnosed early are easily reat-
tached to the tuberosity with pre-
dictably good results regardless of
whether the bicipital aponeurosis
is intact or ruptured.
4,6-8,11,13,17,18
Matthew L. Ramsey, MD
Vol 7, No 3, May/June 1999
201
Fig. 1 Proximal retraction of the biceps
muscle belly with attempted flexion of the
elbow.
However, the results of repair of
chronic ruptures vary and are not
predictable solely on the basis of
the time between rupture and re-
pair. If the bicipital aponeurosis
remains intact, the tendon is pre-
vented from retracting proximally

into the arm. Rupture of the distal
biceps tendon and the bicipital
aponeurosis allows the tendon to
retract proximally. Over time, scar-
ring to the brachialis and retraction
of the tendon into the biceps mus-
cle belly may limit the ability to
obtain sufficient length for anatom-
ic repair.
Treatment
Partial Rupture
The difficulty in treating pa-
tients with partial tears of the distal
biceps tendon lies in proper diag-
nosis. Cubital bursitis, with or
without concomitant bicipital
tendinosis, and partial ruptures can
both present with pain in the ante-
cubital fossa; furthermore, both
conditions may be present at the
same time.
26
The advent of MR
imaging has allowed direct assess-
ment of pathologic changes within
soft tissue that previously could
only be inferred from the history
and physical examination.
27,28
This

has helped define the pathology of
the distal biceps tendon.
Partial distal biceps tendon rup-
tures that fail to respond to nonop-
erative treatment are best managed
surgically. Most partial ruptures
occur at the insertion into the radial
tuberosity.
19,22,24
The most success-
ful surgical results for symptomatic
partial ruptures have been achieved
by releasing the remaining portion
of the biceps tendon from the
tuberosity, debriding the frayed
tendon end, and anatomically reat-
taching the tendon to the radial
tuberosity as if there were a com-
plete rupture.
19,24
Foxworthy and
Kinninmonth
29
reported a case of
median nerve compression from an
enlarged synovial bursa associated
with a partial rupture of less than
50% of the distal biceps tendon,
which was treated with median
nerve decompression and debride-

ment of the biceps tendon. Whether
debridement of the distal biceps
tendon contributed anything to the
improvement in the patientÕs symp-
toms is unclear from this report.
Other authors have not reported
success with debridement of partial
tears of the distal biceps tendon.
19
Elongation of the biceps tendon
without failure at the tuberosity is
an unusual form of partial tearing
reported by Nielsen.
25
The thin,
elongated tendon does not possess
the mechanical integrity of the
intact tendon and behaves clinical-
ly like a complete rupture. Nielsen
used Z-plasty shortening of the
biceps tendon with suture rein-
forcement to reestablish the length-
tension relationship of the biceps
muscle. Postoperatively, flexion
strength and supination strength
were equivalent to those in the
noninjured arm.
Complete Rupture
The superiority of early anatom-
ic repair in returning flexion and

supination strength is well estab-
lished.
4,6-8,11,13,17,18
Although some
patients may choose nonoperative
management of complete ruptures,
they should be told of the possibility
of activity-related pain in the arm
and forearm, as well as decreased
strength and endurance in flexion
and supination. Nonoperative
management should be considered
only for elderly, sedentary patients
who do not require strength and
endurance in flexion and supina-
tion and for patients who are too ill
to undergo surgery.
Single-incision and two-incision
techniques to treat these injuries
have been described. Recently,
with the availability of suture
Distal Biceps Tendon Injuries
Journal of the American Academy of Orthopaedic Surgeons
202
Fig. 2 Fast spin-echo T2-weighted MR images of two patients. A, Normal distal biceps
tendon insertion (arrowhead). B, Partial insertional rupture (arrowhead) with degenera-
tion of the distal biceps insertion (arrow).
A B
Table 1
Classification of Distal Biceps

Tendon Ruptures
Partial rupture
Insertional
Intrasubstance (elongation)
Complete rupture
Acute (<4 weeks)
Chronic (>4 weeks)
Intact aponeurosis
Ruptured aponeurosis
anchors, the use of an anterior
approach has increased in populari-
ty.
16,30,31
When using suture an-
chors and a single-incision tech-
nique for acute distal biceps tendon
ruptures, the radial nerve should be
protected but does not need to be
formally identified and dissected.
31
In chronic cases, the surgeon should
consider identifying the superficial
and deep branches of the radial
nerve to avoid injury if a single
anterior incision is to be utilized. In
this situation, a pullout suture tied
over a bolster or soft-tissue button
or suture anchors are used.
7,13,16,17
Before suture anchors became avail-

able, radial nerve injuries were
reported with single-incision tech-
niques,
3,5,7,12
which prompted the
development of two-incision tech-
niques.
8,14,32
Most authors favor a modified
Boyd-Anderson two-incision tech-
nique for complete ruptures. The
original technique involves subpe-
riosteal exposure of the ulna.
32
This
approach has caused radioulnar
synostosis,
8,12,33
prompting modifi-
cation of the technique. Currently, a
muscle-splitting approach through
the common extensor and supinator
muscles is preferred. Although this
may reduce the incidence of proxi-
mal radioulnar synostosis, it has not
eliminated it entirely.
15
Technique for Immediate
Repair
The patient is placed supine on

the operating room table with the
affected arm extended on an arm
board. A tourniquet can be used if
desired. An anterolateral incision
beginning 5 cm above the flexion
crease along the lateral border of
the biceps is the standard ap-
proach. The incision should curve
medially at the flexion crease of the
elbow to avoid crossing the elbow
at a 90-degree angle to the flexion
crease. This extensive exposure is
unnecessary in acute ruptures; a
transverse incision in the flexion
crease with distal extension pro-
vides adequate exposure and a cos-
metically acceptable incision. The
lateral antebrachial cutaneous
nerve is identified as it pierces the
deep fascia and is retracted lateral-
ly. The deep fascia is incised, and
the distal biceps tendon is identi-
fied. If the bicipital aponeurosis is
intact, the tendon will remain in
the tendon sheath or will retract
proximally and turn back on itself
in the antecubital fossa. If the
bicipital aponeurosis is ruptured,
the tendon will retract proximally
into the anterior compartment of

the arm. The tendon is retrieved
and minimally debrided. Two No. 5
nonabsorbable Bunnell sutures are
passed through the tendon.
If the rupture is acute or the ten-
don remains in the tendon sheath
distally, an extensive soft-tissue dis-
section, including identification of
the radial nerve, is not necessary.
The sheath previously occupied by
the biceps tendon can be easily
identified by blunt finger dissection
down to the radial tuberosity. With
the forearm in supination, a blunt
hemostat is advanced along the
medial border of the radial tuberos-
ity to the dorsolateral aspect of the
proximal forearm; care must be
taken not to violate the periosteum
of the ulna (Fig. 3).
A second incision is made over
the hemostat down to the fascia
overlying the common extensor
muscle mass. The common exten-
sor muscle mass and supinator
muscles are split down to the radial
tuberosity with the forearm in max-
imal pronation. A high-speed burr
is used to create a cavity in the radi-
al tuberosity large enough to accept

the distal biceps tendon. Three
small drill holes are placed along
the margin of the cavitated tuberos-
ity. The sutures are passed from
the anterior incision through to the
second incision (Fig. 4). The tendon
is passed deep and medial to the lat-
eral antebrachial cutaneous nerve.
The sutures are passed through the
drill holes and tied. The wounds
are closed in layers, and the elbow
is immobilized in 90 degrees of flex-
ion with the forearm in supination.
Technique for Delayed Repair
The need to repair chronic rup-
tures of the distal biceps remains
questionable. Chronic ruptures are
more difficult to repair than acute
ruptures. However, the disability
Matthew L. Ramsey, MD
Vol 7, No 3, May/June 1999
203
Fig. 3 A, The ulnar periosteum is not exposed in the modified muscle-splitting two-inci-
sion technique (dotted line shows correct direction of incision). B, Care must be taken not
to violate the ulnar periosteum when passing the hemostat to the dorsolateral aspect of the
forearm or when making an incision on that surface (dotted line shows incorrect direction
of incision).
Correct
Incorrect
A

B
associated with a chronic rupture
often justifies the attempt at repair
even though the results are not as
predictable as those after immedi-
ate repairs.
Anatomic repair of the ruptured
tendon to the tuberosity is the goal
of delayed repair if improved
strength and endurance are neces-
sary. If surgery is being performed
because of activity-related pain in
the arm and forearm, tenodesis to
the brachialis can be considered,
with the understanding that supi-
nation strength and endurance will
not improve.
Proximal retraction of the rup-
tured tendon may preclude ana-
tomic reattachment because of a loss
of tendon length. An intact bicipital
aponeurosis will limit proximal
retraction of the tendon, making
repair somewhat easier. Inadequate
tendon length should be anticipated
preoperatively and discussed with
the patient so that an alternative
source of graft to extend the tendon
can be planned. Autogenous tissue
is preferred to synthetic materials.

Rolled fascia lata or semitendinosus
autograft are acceptable graft mate-
rials. The semitendinosus tendon is
similar in caliber to the native
biceps tendon and has performed
well in clinical use.
34
In cases of chronic rupture, the
distal biceps tendon sheath is
scarred, necessitating a more exten-
sive dissection. Identification and
protection of the radial nerve are
warranted in this situation.
The graft should be passed from
anterior to the posterolateral incision
and fixed to the tuberosity, as de-
scribed for an immediate repair.
With the elbow in 45 to 60 degrees of
flexion, the graft is woven through
the distal end of the native biceps
tendon and secured to itself (Fig. 5).
Postoperative care is similar to that
for immediate repairs.
Postoperative Rehabilitation
The extremity is immobilized
with the elbow in 90 degrees of flex-
ion and the forearm in supination
for 7 to 10 days. A hinged flexion-
assist splint with a 30-degree exten-
sion block is used to protect the re-

pair until 8 weeks postoperatively.
The splint is then removed, and un-
restricted motion and progressive
strengthening are begun. Unre-
stricted activities, including strenu-
ous lifting, are not allowed until 5
months after repair.
The rehabilitation program for
patients with delayed repairs is
similar to that for patients with
acute repairs. The limit of active
extension in the early postoperative
period is dictated by the tension in
the biceps tendon.
Results
As mentioned previously, numer-
ous early reports on the treatment of
distal biceps tendon ruptures indi-
cated that satisfactory results could
be obtained, with return of normal
or near-normal strength and func-
tion, regardless of the method of
treatment. Some authors advocated
nonoperative management of these
injuries, citing normal return of
strength and function and docu-
menting the ability to return to
work earlier than after surgical
treatment.
1,2

Other authors sup-
ported attachment of the biceps ten-
don to the brachialis muscle.
4,12
This position was historically advo-
cated in 1941 by Dobbie,
12
who was
Òimpressed with the numerous
important structures identified and
contained in this anatomic region
Distal Biceps Tendon Injuries
Journal of the American Academy of Orthopaedic Surgeons
204
Fig. 4 The exposed tuberosity is excavated with a high-speed burr, taking care to leave
the thicker cortical bone along the radial border of the tuberosity intact. Three drill holes
are made along the radial side of the tuberosity. The sutures are passed through the drill
holes and tied with the forearm in neutral position to prevent the sutures from pulling out
of the drill holes. (Adapted with permission from the Mayo Clinic, Rochester, Minn.)
Biceps tendon
and was thoroughly convinced that
exposure of the tubercle was
impractical and unwise.Ó Reattach-
ment of the biceps tendon to the
brachialis muscle simplified the sur-
gical procedure considerably and
avoided the potential complication
of radial nerve injury.
3,12
However,

objective strength data demonstrate
no improvement in supination
strength.
8
As the role of the biceps muscle
in elbow strength and function
became known, support for early
anatomic repair grew. In 1985,
Morrey et al
8
reported loss of flexion
and supination strength by as much
as 50% with nonoperative treatment.
Similarly, Baker and Bierwagen
4
documented objective deficiencies in
flexion and supination strength of
21% and 27%, respectively. Equally
impressive were the losses of flexion
and supination endurance, estimat-
ed at 21% and 47%, respectively.
While this degree of loss of strength
may not be incapacitating for many
activities of daily living, activities
that require sustained strength and
endurance can be severely limited.
When one considers that this injury
occurs most frequently in the domi-
nant extremity in heavy laborers, it
is not surprising that these deficits

can be disabling.
Surgical repair is the more re-
cently accepted approach. Nu-
merous studies have reported ex-
cellent results with early anatomic
repair of the distal biceps ten-
don.
4,6-8,11,13,17,18
Morrey et al
8
reported 97% flexion strength and
95% supination strength compared
with the uninvolved extremity.
Other authors have demonstrated
similar return of strength and en-
durance but have reported differ-
ences based on hand dominance.
Repaired nondominant extremities
demonstrated mild weakness and
lack of endurance compared with
the uninvolved dominant extremi-
ty; however, strength and endur-
ance of the repaired dominant ex-
tremity were equivalent to those in
the unrepaired nondominant ex-
tremity.
4,11,15
Patients with chronic ruptures
(>4 weeks) present a difficult chal-
lenge. Proximal retraction of the

biceps muscle and scarring to the
brachialis can occasionally make
anatomic repair impossible. Fascia
lata autograft,
3,13
a semitendinosus
autograft,
34
and a ligament aug-
mentation device wrapped with
fascia lata
20
have all been used to
extend a shortened biceps muscle.
Strength in flexion and supination
is improved in comparison to rup-
tured tendons treated nonopera-
tively, but the degree of improve-
ment varies.
5,8,34
Boucher and Mor-
ton
5
reported 50% residual flexion
weakness in a patient treated 4.5
months after injury. Hang et al
34
found only 13% flexion and 14%
supination deficits in a patient
treated with semitendinosus aug-

mentation 1 year after injury. Al-
though late repairs carry a greater
risk of providing no improvement
in strength, surgery should be con-
sidered for patients with consider-
able disability.
When partial rupture of the dis-
tal insertion has been successfully
managed by releasing the remain-
ing tendinous insertion to the
tuberosity and reattaching the ten-
don as if it were completely rup-
tured, patients have been able to
return to normal work activities
without difficulty.
19,24
Bourne and
Morrey
19
evaluated postoperative
strength data after release and
repair of partially ruptured ten-
dons and found normal values in
one patient and a decrease by 33%
in supination with normal flexion
strength in a second patient.
Nielsen
25
has reported a case of
biceps tendon elongation with

mechanical insufficiency of the
biceps muscle. After nonoperative
treatment failed to improve the
patientÕs symptoms, a Z-plasty
shortening of the tendon was per-
formed, which restored power to
the extremity.
Complications
Many authors have reported radial
nerve injury after repair with the
use of a single-incision anterior
approach.
3,5,7,18
Fortunately, when
a radial nerve palsy occurs, it typi-
cally resolves completely, although
permanent radial nerve injury has
been reported.
3
Although a two-incision repair
decreases the incidence of radial
nerve injury, proximal radioulnar
Matthew L. Ramsey, MD
Vol 7, No 3, May/June 1999
205
Fig. 5 The semitendinosus graft is
secured to the radial tuberosity through
drill holes. With the arm in 45 to 60
degrees of flexion, the graft is woven
through the distal biceps tendon stump

and secured to itself. (Adapted with per-
mission from Hang DW, Bach BR Jr,
Bojchuk J: Repair of chronic distal biceps
brachii tendon rupture using free autoge-
nous semitendinosus tendon. Clin Orthop
1996;323:188-191.)
synostosis has been reported as a
potential complication of this ap-
proach.
8,12,15,33
Use of a muscle-
splitting approach instead of the
original technique of subperiosteal
ulnar dissection may reduce the
incidence of this complication.
Summary
Rupture of the distal biceps tendon
can be disabling for individuals who
require upper extremity strength for
vocational and recreational activi-
ties. It occurs when an unexpected
extension force is applied against a
contracting biceps muscle. Rupture
probably occurs through a tendon
weakened by intrasubstance degen-
eration or external mechanical im-
pingement.
The history and physical exami-
nation are usually sufficient to
make the diagnosis. The hallmark

is a palpable defect in the distal
biceps, which is accentuated by
attempted elbow flexion. Weak-
ness on supination is easily demon-
strated; flexion weakness is more
subtle. Radiologic evaluation,
including plain radiographs and
MR images, is generally not neces-
sary to make the diagnosis. Mag-
netic resonance imaging may occa-
sionally be useful in differentiating
among biceps tendon degeneration
(tendinosis), cubital bursitis, and
partial distal tendon ruptures.
Immediate surgical repair of the
ruptured biceps tendon is advocated
for optimal return of function. Use
of a two-incision muscle-splitting
approach and nonabsorbable su-
tures is recommended for secure
repair. Techniques that utilize a
single anterior incision are ade-
quate but require protection of the
radial nerve to avoid nerve injury.
The use of suture anchors may sim-
plify the procedure. In the case of a
chronic rupture, there may be inad-
equate tendon length to reach the
radial tuberosity. Autogenous tis-
sue or an augmentation device can

be considered in this situation. The
results of late repair are less pre-
dictable for return of strength, but
activity-related pain is diminished.
Symptomatic partial tendon
ruptures are rare. Failure of non-
operative management may be
treated by release and repair of the
partially torn tendon. However,
experience with surgical treatment
is limited.
Postoperative rehabilitation
involves protection of the repair
against any lifting force for 6 to 8
weeks. Initially, the arm is immo-
bilized in a splint with the elbow in
90 degrees of flexion and the fore-
arm in supination for 7 to 10 days.
A flexion-assist splint with a 30-
degree extension block is utilized
for 6 to 8 weeks postoperatively.
Unrestricted range-of-motion exer-
cises and gentle strengthening are
begun at 8 weeks. Return to unre-
stricted activity is allowed by 5
months after surgery.
Distal Biceps Tendon Injuries
Journal of the American Academy of Orthopaedic Surgeons
206
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Matthew L. Ramsey, MD
Vol 7, No 3, May/June 1999
207