Pathologic Humerus Fracture
Bony lesions may result in pathologic fractures. These
lesions, when not of mesenchymal origin, commonly include
myeloma, lymphoma, and most commonly metastastic carcinoma.
The axial skeleton is the third most common site of
bony metastasis, after the lung and liver. Of the 1.2 million
new cases of cancer each year in the United States, one half
will metastasize to the skeleton1. The tumors most likely to
metastasize to bone are prostate (32%), breast (22%), kidney
(16%), lung and thyroid1.
Metastatic disease to the axial skeleton occurs much more
frequently in the spine, pelvis, ribs, and lower extremities than
in the humerus. Yet, metastasis to the humerus accounts for
20% of osseous metastasis. The humerus is the second most
common site for long bone metastases, behind only the femur
in its frequency of involvment. In multiple myeloma, the
majority of patients have pathologic fractures at the time of
diagnosis, and up to 30% of patients present with non-vertebral
Metastasis to the long bones usually reflects an advanced
disease state. It has been recommended that the majority of
patients with metastatic bone tumors receive multidisciplinary
care from a team including orthopaedic oncologists, radiotherapists,
Historically, pathologic humerus fractures have been treated
non-operatively with casts, splints, or braces in conjunction
with radiotherapy. However, the functional outcome for these
patients was poor, as use of the arm was extremely limited.
As a result, surgical techniques for fracture stabilization have
been employed using endoprostheses, polymethylmethacrylate
(PMMA), and modern methods of fracture management. The
success in functional improvement and pain relief has led to
the much broader use of operative treatment in patients with
Anatomic and Physiological Considerations
Anatomically and biomechanically, the humerus can be
divided into its proximal, middle, and distal thirds. Although
the humerus is not a weight-bearing bone in normal individuals,
patients with metastatic disease often have lower extremity
involvement resulting in a greater dependence on the upper
extremities to aid in transfers and weight-bearing. The method
of operative fixation depends upon several factors including the
location and size of the lesion, as well as the quality of the bone
surrounding the tumor mass.
In the proximal humerus, the bone is subject to extremes
of bending and rotational forces from its various muscle insertions.
Preservation of rotator cuff function, when possible, will
help to maximize post-operative function. As a result, lesions
in the proximal epiphysis are typically treated with cemented,
long-stemmed endoprostheses with preservation of the rotator
cuff insertions onto the greater tuberosity. The proximal
metaphysis is mostly cancellous bone, and stable fixation is difficult
to achieve. Lesions in the metaphysis are reconstructed
using a modular prostheses, and the rotator cuff insertions are
re-attached to the implant using non-absorbable sutures when possible.
In the narrow diaphysis, metastatic lesions place the
humerus at greatest risk for fracture. Thus, operative fixation is
used more aggressively than in the proximal or distal humerus.
Intramedullary fixation with flexible or rigid constructs is the
treatment of choice for these lesions. However, unlike the
femur, the medullary canal in the humerus is short and narrow.
As a result, rigid, interlocked intramedullary devices often
require significant amounts of reaming, and the proximal and
distal interlocking screws require good bone quality to achieve
functional stability. If either of these criteria is not met, Rush
rods or Enders nails are utilized for fracture or impending fracture
Supracondylar lesions, like the proximal humeral metaphysis,
are best treated with open reduction and internal fixation
using PMMA augmentation if there is sufficient normal bone
proximal and distal to the metastatic lesion. If not, endoprosthetic
implants with cement fixation remain the treatment of
choice for these lesions.
Evaluation of the patient with metastatic disease starts
with a thorough history and physical examination. Quality
plain radiographs are essential for formulating a differential
diagnosis and should include a chest x-ray and orthogonal
views of the involved extremity. Whole-body technetium-
99m-phophonate bone scintigraphy should also be performed
to evaluate the entire skeleton for other sub-clinical sites of
metastasis. It is not uncommon for bone scans in patients
with multiple myeloma to fail in identifying bony involvement.
Computed tomography (CT) scans of the chest, abdomen,
and pelvis should also be obtained to assess for the presence
of visceral metastasis. A serum laboratory panel including a
protein electrophoresis, complete blood count (CBC), lactate
dehydrogensase, serum calcium, erythrocyte sedimentation
rate and alkaline phosphatase should also be checked. Lastly,
in the patient with suspected metastatic disease, CT scans of
the involved extremity can be useful in assessing the extent of
cortical bone involvement and determining the risk of impending
The indications for non-operative treatment are dependent
on the size and location of bony involvement and on patient
factors. Asymptomatic and small symptomatic lesions which
involve less than 50% of the cortex are generally felt to be at
low risk for fracture. Patients with life expectancies of less
than 3 months and profound metastatic involvement of the
upper extremity prohibiting adequate bony stabilization are
generally considered non-operative candidates. Also, patients
who do not use external aids for ambulation may be managed
As with non-operative treatment, the indications for surgical
intervention reflect the level of local disease progression and
the overall condition of the patient. The goals of surgical treatment
are pain relief and improved functional use of the affected
extremity. Surgical stabilization of symptomatic impending or
pathologic fractures is frequently provided, as the life expectancies
of patients with metastatic disease can vary considerably,
and patients with advanced disease may live for several months.
Other indications for operative treatment include osteolysis of
more than 50% of the cortical diameter of the humerus in
either the longitudinal or coronal plane. CT scan may be the
best modality for evaluation of cortical lysis. Also, symptomatic
lesions in the proximal third or midshaft of the humerus occur
in areas of high biomechanical stress and are at particular risk
for fracture. Lesions in these areas should be treated more
aggressively with surgical intervention. Finally, surgical stabilization
is indicated if the humerus is persistently painful with
weight-bearing or if local progression of the tumor continues
despite the institution of chemotherapy or radiation.
The type of operative procedure used to treat patients
with metastatic disease of the humerus varies depending on
the location and extent of the lesion as well as the experience
of the surgeon. The choices for operative fixation include:
internal fixation with plates and screws with or without PMMA
enhancement; intramedullary nailing with or without interlocking
devices; prosthetic replacement of the proximal or distal
humerus; and segmental replacement with intercalary spacers.
While the primary goals of surgery are to restore function and
relieve pain, the surgeon should also biopsy the lesion in question
to confirm or clarify the underlying diagnosis.
In comparison to plate osteosynthesis, locked intramedullary
nailing involves less soft tissue injury, a lower rate of
infection, and a theoretically smaller risk of radial nerve injury.
(Figure 1) Most rigid humeral nails are inserted in an antegrade
fashion. Disadvantages of this technique include the
risk for impaired shoulder function secondary to rotator cuff
injury during nail insertion and shoulder impingement from
When performing intramedullary fixation of the humerus,
the patient is usually placed supine in the beach chair position,
with the entire affected extremity prepped and draped.
A skin incision of approximately 4 cm is made longitudinally
over the greater tuberosity. The deltoid muscle is split and the
subdeltoid bursa is exposed in line with the incision. Palpation
is used to identify the sulcus medial to the greater tuberosity
of the proximal humerus, and a 1 cm incision is made in the
supraspinatus tendon over the sulcus. Prtoecting the rotator
cuff, a 5mm drill bit is used to enter the medullary canal
and a 2.5mm guide pin is then passed across the impending
or pathological fracture site. The medullary canal is reamed
sequentially in 0.5mm increments. If the patient has osteoporotic
bone, reaming may be unnecessary. If the patient's bone
is of good quality outside of the metastatic lesion, as little reaming
as possible should be performed to place the rod within the
medullary canal. It should be noted that guide pin placement
and reaming may be difficult in cases of osteoblastic lesions.
The intramedullary rod is passed over the guide wire until the
proximal part of the nail is countersunk within the humeral
head. Compression across the fracture is achieved manually
or with the "backstrike" technique after the distal interlocking
screw has been placed. Locking screws are placed lateral-to-medial
in standard fashion. Fluoroscopy is used to ensure that
adequate compression across the fracture has been achieved
prior to placing interlocking screws. Finally, fluoroscopy is
employed to check bony alignment and implant position prior
to the end of surgery.
Arthroplasty for pathologic fractures is utilized if the lesion
involves the proximal 1/6th of the humerus, the distal 1/3 of the
humerus, or if there is inadequate bone stock to allow for adequate
bony fixation using conventional techniques. (Figure 2)
If the insertion of the rotator cuff or deltoid muscles is
not preserved during proximal humeral hemiarthroplasty, the
patient must rely upon scapulothoracic motion to abduct the
arm unless myodesis of these muscles to the implant is performed.
Amputation is rarely necessary for the treatment of
metastatic disease of the humerus unless there is intractable
pain or seeding of the soft tissues surrounding the metastatic
When performing hemiarthroplasty of the proximal
humerus, the patient is placed in modified beach chair position.
An extended deltopectoral approach is used. The cephalic
vein may be ligated or mobilized away from the operative field.
Total shoulder replacement is rarely performed, as hemiarthroplasty
is associated with reduced operative time, blood loss, and
If a lesion of the distal humerus is being addressed, the
biceps is retracted medially and the brachialis is split in its midline.
The radial nerve is identified below the level of the deltoid
insertion and protected. The brachioradialis and common wrist
extensors are detached from the lateral humerus. Total elbow
replacement is usually performed.
Plate and Screw Fixation with Polymethylmethacrylate
This technique for operative fixation can be used as an
alternative to intramedullary fixation of the humerus when
endoprosthetic replacement is not indicated. (Figure 3)
When performing internal fixation, the patient is prepped
and draped in the same manner as described above. An
extended deltopectoral approach is used to apply the plate and
screws to the humerus. In the proximal humerus, a 4.5 mm
direct compression plate with 6.5mm cancellous and 4.5 mm
cortical screws may be used. In the diaphysis, the use of two
orthogonal plates increases the rigidity of the construct. Newer
locking plates may also be used. PMMA is then injected into
the osseous defect and around the fixation device prior to closure
over suction drains.
Pathologic humerus fractures are potentially disabling
and difficult problems. The location and size of the lesion and
the overall patient prognosis dictate the plan of care for each
patient. Surgical treatment of metastatic humeral lesions is
an effective means of relieving pain from impending or fractured
pathologic lesions. Surgical stabilization of these lesions
improves the function of the affected upper extremity in these
patients so that they are able to enjoy an improved quality of
life, utilize the upper extremity in assisted weight-bearing, and
reduce the need for nursing care by maximizing the patient
Drs. Gobezie and Ponce are Residents, Harvard Combined Orthopaedic Residency Program, Boston, MA.
Dr. Ready is Assistant Professor of Orthopaedic Surgery at Harvard Medical School and Attending Physician, Department of Orthopaedic Surgery, Brigham and Women's Hospital, Boston, MA.
Address Correspondence to:
Dr. John Ready
Division of Orthopaedic Oncology
Department of Orthopaedic Surgery
Brigham and Women's Hospital
75 Francis Street
Boston, Massachusetts 02115
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