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http://www.medscape.org/viewarticle/420404

Metastatic Bone Disease

Faculty and Disclosures

CME/CE Information

Introduction

Effective treatments for prevention of bone metastases have begun to replace old methods

of treatment after the fact. At the same time, ne surgical procedures and devices can

restore function more !uic"ly and more durably than before. Aggressive surgicalresection of metastatic bone lesions in selected patients no offers the hope of long#term

survival and even of potential cure here once there as no hope of survival. $his

symposium provided an update on the "noledge re!uired for rendering optimum care to

patients ith metastatic bone disease.

Epidemiology: Avoiding the Pitfalls

Mary %&Connor, MD,

'()

spo"e on the diagnosis of metastatic disease. Cancer representsthe second most common cause of death in the *nited +tates, here there are (. million

ne cases of invasive cancer per year. In men, the most common sites are prostate, lung

and colon- in omen, they are breast, lung, and colon. +urvival continues to improve butonly slightly, ith the average #year survival rates for *+ hites in lung, breast, prostate

and colon cancer of (, 01, 2, and 34, respectively. Distressingly, African

Americans on average have (5 to ( loer survival rates in the same interval. 6ong#

term survival in some groups means that the orthopaedic surgeon must plan for durablefi7ation of pathologic fractures in many cases.

%rthopaedic tumor specialists often see patients for hom there has been a mista"e in

diagnostic or surgical management that has adversely affected function or survival. $hese

errors often share a common feature8 a rush to 9udgment and treatment rather than aninformed, methodical evaluation. %ne possible cause for the rush is the e7treme an7iety

the discovery of metastatic disease provo"es in the patient and family. Many people

e!uate :cancer in the bones: ith certain death, so the emotional reactions may bee7treme. ;ot surprisingly, the physician feels pressured to act !uic"ly. $his scenario sets

the stage for some of the more common pitfalls orthopaedic surgeons must avoid in the

management of metastatic bone lesions.


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• urinalysis

• digital rectal e7amination in males

$he physical e7amination should cover the area of interest as ell as the s"in, the local

and regional lymph nodes, and the screening e7ams mentioned above. 6abs may include8

• a complete blood cell count

• Chem#, +E/*E

• rostate#specific antigen in men

• urinalysis

Predicting the Risk of Pathological racture

Dr. Bary Friedlaender '() described the history of guidelines for assessing pathologicfracture ris". $he first studies, conducted by eals and +nell beteen (23 and (23(,

loo"ed at pathologic fractures of the femur in patients ith breast carcinoma metastatic to

bone. %f the (2 fractures that occurred in their first series, they found that 0 ere predictable using the folloing criteria8

• presence of a metastatic lesion . cm in si=e or larger involving the femoral

corte7

• presence of a defect of the same si=e in any location that caused pain to the patient

In (21, Fidler ') retrospectively studied (2 patients ith pathological fractures of thefemur. e found that all patients ith greater than 5 cortical involvement developed a

fracture. ased on this data, he recommended that patients ith involvement of over half

of the corte7 should undergo surgery to stabili=e the bone. ic"el and Mourandian

studied 4 patients ith lesions in the pro7imal femur and concluded that involvement ofeven small parts of the corte7 in the subtrochanteric region places the femur at high ris"

for fracture and arrants prophylactic fi7ation.') +i=e of the lesion did not correlate ith

ris" of fracture.

In (20, arrington'4) recommended intramedullary nail fi7ation hen greater than 15

destruction of the corte7 is present, rather than 5 cortical involvement. arrington also

pointed out that many of the bone metastases that eventually lead to pathologic fracture


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cause radiographic changes that are diffuse or difficult to measure, ma"ing ris"

assessment difficult.

+everal authors have demonstrated the limitations of using si=e#based criteria alone. In(203, Geene and colleagues') reported that many metastases could not be accurately

measured from plain radiograph because they lac"ed a clear border beteen the lesionand normal bone. *nable to identify a consistent relationship beteen the si=e of the

lesion and ris" of fracture, the authors recommended using other criteria. In addition, inmetastatic cancer producing blastic lesions, the e7tent of bone destruction can be difficult

to assess from plain films. +i=e#based criteria may not be applicable to bony lesions

here the corte7 cannot be effectively measured, such as those of the spine, ribs and pelvis.

In (202, Mirels'3) developed a scoring system to !uantify the ris" of pathologic fracture

based on a retrospective study of 10 irradiated metastatic bone lesions. *nli"e the

previous studies, Mirels combined 4 different features of bone lesions in an attempt to

create a more reliable ris" assessment. $he system assigned points to the folloing 4variables8

• the location of the lesion ?upper limb, loer limb, peritrochanter@

• the degree of pain caused by the lesion ?mild, moderate, severe@

• the type of lesion ?lytic, blastic, mi7ed@

•

the degree of corte7 ta"en up by the lesion ?H(/, (/#/, (/@

Mirels& data indicated that on a scale of (, a score of less than or e!ual to 1 is indicative

of a lo#ris" lesion. A score of 0 is associated ith a ( ris" for fracture, hile the ris"

of fracture is in patients ith a score of 2. Mirels concluded that a score of 2 or

greater should be used to indicate the need for prophylactic fi7ation.

!a"le #$ Mirels% Scoring System

Variable Score

1 2 3

+ite *pper limb 6oer limb eritrochanter


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ain Mild Moderate +evere

6esion lastic Mi7ed 6ytic

+i=e H(/ (/#/ /

&pper E'tremity Metastasis

Dr. Michael Joc" '()

spo"e on metastases to the upper e7tremities, here only 5 of bony metastasis occur. alf of these metastases are in the humerus. oever, the impact

on patient is as disabling as in the loer e7tremity.

In the pro7imal humerus, a hemiprosthesis ith long stem or plates ith

methylmethacrylate are normally used. In selected patients here prolonged survival isanticipated, a custom prosthesis or an alloprosthetic composite is used.


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Dr. Fran"lin +im'() discussed metastases to the pelvis, a fre!uent site of involvement in

hich lesions cause considerable disability. +election of the best treatment re!uires

careful consideration because of the e7tensive nature of the surgery and the much longerrecovery period. $he goal is immediate stability for eight#bearing and durable fi7ation

that ill avoid the need for another surgery. Joutine radiographs are not sufficient to

evaluate bone loss, ma"ing C$ scans recommended in virtually every case.

Dr. +im presented the arrington classification of periacetabular metastases, along ithrecommended treatments ?arrington (20(@'0)8

(lass I: )ateral cortices* superior* medial +alls intact$ $hese tend to be small cavitary

lesions. +tandard total hip arthroplasty is sufficient to manage these smaller lesions.

(lass II: Medial +all deficient or medial +all and dome$ $here is a high ris" of medialmigration, ma"ing total hip arthroplasty ith reinforcement of the medial all ith ire

mesh, a protrusio ring, and methylmethacrylate indicated. A variety of protrusio rings are

available, and selecting the best device ill facilitate the procedure. $he ring is molded tofit the bone as much as possible. $he femoral component must be selected so that there is

no impingement against the rim of the protrusio ring, hich is more e7tensive than that of

a normal acetabular prosthesis.

(lass III: )ateral cortices and dome are deficient$ $he optimal procedure involves theuse of multiple large threaded +teinmann pins drilled into remaining ileum,

methylmethacrylate, and a protrusio ring. $o groups of pins are inserted. %ne is inserted

distal to pro7imal into the posterior all area, and the other is inserted through the ileumfrom the anterior parts to support the anteriorly directed forces.

(lass I,: Resection is re-uired for potential cure$


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plate device. Augmentation ith methylmethacrylate adds considerably to the chances of

success hen a nail plate is used.

Managing these lesions prophylactically is far superior to intervention after the fact. $hesurgeon should carefully assess the ris" of pathological fracture ?see above@ and intervene

proactively henever possible. $he entire femur should be e7amined to detect lesionsthat may e7ist distal to the "non lesion.

+ome lesions should be resected rather than rodded. atients ho respond ell tochemotherapy, patients ith renal tumors, diffuse disease present over several

centimeters of the femur should be considered for resection and reconstruction ith a

modular oncology prosthesis.

Dr. Bitelis'() presented the folloing recommendations for surgery, depending on theinvolvement of the metastases8

Femoral nec" or intertrochanteric region, remaining bone structurally ade!uate8

• +ide plate and methylmethacrylate or hemiarthroplasty

Femoral nec" or intertrochanteric region, remaining bone structurally inade!uate8

• hemiarthroplasty fi7ed ith cement

+ ubtrochanteric region, remaining bone structurally ade!uate8

• reconstruction nail and methylmathacrylate

• Calcar replacement prosthesis

• pro7imal femoral resection/ modular prosthesis


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• replacement ith modular prosthesis

emoral and !i"ial Shaft Metastasis

Dr. Joss


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4. arrington GD. ;e trends in the management of loer e7tremity metastases.

Clin %rthop (20-(328#3(.

. Geene K+, +ellinger D+, Mceath AA, Engber

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