líeview Article

Apophyseal Avulsion Fractures of theHip and PelvisBART I. MCKINNEY, M D ; CORY NELSON, M D ; WESLEY CARRION, M D

educational objectivesAs a result of reading this article, physicians should be able to:

1. Describe the anatomy and mechanism of injury associated with apophy-seal avulsion fractures of the hip and pelvis.

2. List the different stages of nonoperative management in patients withapophyseal avulsion,

3. Discuss the operative treatment options and surgical approaches for treat-ment of these injuries.

4. Identify the controversies and common complications in the treatment ofapophyseal avulsion fractures of the hip and pelvis.

A pophyseal avulsion fractures ofthe hip and pelvis are injuriesthat usually occur in the ado-

lescent athlete. However they may pres-ent in a patient as late as the mid-20s.'If not properly diagnosed and treated,these injuries can he debilitating toan adolescent athlete. An increase ofadolescent participation in competitivesporting activities and hetter musculo-skeletal imaging techniques has led toan increased awareness of these injurieshy the medical community. Apophysealavulsion fractures are usually the re-sult of a sudden forceful concentric oreccentric contraction of the muscle at-tached to the apophysis. Like other pe-diatric fractures, apophyseal avulsionfractures fail through the physis.' Theprimary age for these injuries to occur isbetween 14 and 25 years.'•'••*

This article reviews the most commonsites of avulsions, anatomy, findings onhistory and physical examination, imagingcommonly used in establishing the diag-nosis, treatment, physical therapy proto-col, and when these patients should returnto sports. While the mainstay of treatment

is nonopemtive, controversies exist regard-ing operative treatment. What are the indi-cations for surgery? U these injuries are tohe treated operatively, what type of fixa-tion should be used? This article will pro-vide the reader with a hetter understandingof these controversies and what recom-mendations are in the literature.

COMMON SITES OF AVULSION IN THEHIP AND PELVIS

Metzmaker and Pappas^ reviewed 27cases of avulsion fractures and found themost common location to he the anteriorsuperior iliac spine. Other common loca-tions that were found included the ischialtuherosity. anterior inferior iliac spine,lesser trochanter and iliac crest. In thelargest study evaluating these injuries.

Drs McKinney, Nelson, uml Carrion are pom Stony Brook University Hospifal, Stony Brook. New York.Drs McKinney, Nehoii. and Carrion have no relevan! financial relationships to disclose. Dr Mor-

gan, CME Editor, has disclosed the following relevant financial relationships: Sttyker. speakers bureau:Smith & Nephew, speakers bureau, research ¡itant recipient: AO International, speakers bureau, re-search grant recipient: Synthes. institutional support. Dr D 'Ambrosia. Editor-in-Chief, has no relevantfinancial relation.ships to disclose. The staff of ORTHOPEDICS have no relevant financial relationshipsto disclose.

The material presented at or in any Vindico Medical Education continuing education activity doesnot necessarily reflect the views ami opinions of Vindico Medical Education or ORTHOPEDICS. Nei-ther Vindico Medical Education or ORTHOPEDICS, nor the faculty endorse or recommend any tech-niques, commercial products, or manufacturers. The faculty/authors may discuss the use of materialsand/or products that have not yet been approved by the US Eood and Druf" Administration. All readersand continuing education participants should verify all information before treating patients or utilizingany product.

Correspondence should be üddres.^ed to Bart I. McKinney, MD. 3176 Birdseye Circle, Gulf Breeze,FL 32563.

42 ORTHOPEDICS

APOPHYSEAL AVULSION FRACTURES OF THE HIP AND PELVIS I MCKlNNEY ET AL

Cover illustration © Lisa Clark

JANUARY 2009 Volume 32 • Numher 1 43

Review Article

Rossi and Dragoni"* found the most com-

mon locations were the ischiai tuberosity

(54%), anterior inferior iliac spine (22%),

anterior superior iliac spine (19%), supe-

rior comer of pubic symphysis (3%), and

iliac crest (1%). Soccer (74 cases) and

gymnastics (55 cases) had the highest

number of avulsion fractures documented.

We feel the difference in the two studies

is most likely due to sample size. Metz-

maker and Pappas^ reviewed a case series

of 27 patienis. while Rossi and Dragoni"*

reviewed >1000 radiographs and found

203 avulsion fractures. Apophyseal avul-

sion fractures of the greater trochanter

have also been documented in the litera-

ture.^ ' Although rare, bilateral avulsion

fractures ean occur.''

ANATOMY111 order to properly diagnosis and treat

these injuries, it is vital to understand the

aniitoniy associated with the apophyseal

avulsion fracture (Figure 1). The direct

head of the rectus femoris muscle origi-

nates from the anterior inferior iliac spine

and inserts through the common quadri-

ceps tendon onto the patella. Because it

crosses two Joints, patients with anterior

inferior iliac spine avulsion fractures may

have weakness in both hip flexion and knee

extension. The anterior superior iliac spine

is the origin of the sartorius and tensor fas-

cia lata. Like an anterior inferior iliac spine

avulsion, weakness of hip flexion and knee

extension may be present in someone with

an anterior superior iliac spine avulsion

fraeture. There may even be some loss

of hip abduction in anterior superior iliac

spine avulsion fractures as the sartorius is a

weak hip abductor.

External and abdominal obliques origi-

nate from the iliac crest. Apophyseal avul-

sion fractures of the iliac crest are usually

the result of a trunk twisting injury. The

proximal attachment site of the hamstrings

is the ischiai tuberosity. Weakness of knee

flexion and liip extension is a characteris-

tic of isehlal tuberosity avulsion fracture.

The hip adductors originate from the pu-

bic symphysis and insert onto the lemur.

An adolescent athlete with pubic symphy-

sis avulsion fracture will have pain and

weakness with hip adduction. The lesser

troehanter can also be a site ol'apophyseal

avulsion fracture. The iliopsoas muscle in-

serts onto the lesser trochanter and flexes

the hip. The insertion of the hip abductors

on the greater trochanter is another site for

an apophyseal avulsion fracture.

In their classic article describing

growth plate injuries, Salter and Harris-

describe 2 types of epiphysis: a traction

epiphysis and a pressure epiphysis. A trac-

tion epiphysis is the site of the insertion or

origin of a major muscle or muscle group.

A pressure epiphysis is situated at the end

of a long bone and is subjected to pres-

sure across the joint. They state that the

weakest point of a traction epiphysis is the

Figure 1 : Radiograph demonstrating the possible sites of apophyseal avulsion fractures about the hip andpelvis, iliac crest (white arrow). ASiS (orange arrow), AiiS (red arrow), pubic symphysis (green arrow),ischiai tuberosity (yellow arrow), greater trochanter (purple arrow), lesser trochanter (blue arrow). Figure2: Radiograph of a 15-year-old boy, who sustained an injury whiie playing hockey, demonstrates an avul-sion fracture of the anterior inferior iliac spine (arrow).

epiphyseal plate because the Sharpey's fi-

bers attaching the muscle to the epiphysis

are stronger than the junction of cells be-

tween the calcified and uncalcified epiph-

ysis.' Salter and Harris- found this weak

junction of cells where the separation usu-

ally occurs in the /one of hypertrophy.

HISTORY AND PHYSICAL EXAMINATIONThese patients usually present with a

history of sudden pain during an activity

such as a sporting event. The pain is most

severe during activity and improves with

rest. Swelling and local tenderness may

be appreciated by palpation. The patient

may actively guard against contraction of

the musculature attached to the injured

apophysis. Passive stretch of these mus-

cles will reproduce the pain. A limp may

be present. There is a noticeable weak-

ness in the muscle group attached to the

avutsed apophysis compared to the con-

tralateral side.

The examination of these patients may

mimic an acute episode of apophysitis. It

is important to know tbe signs of apophy-

sitis and how it can be differentiated from

an acute avulsion fracture. Apophysitis is

an inflammation of the apophysis that is

usually caused by overuse or repetitive

traction to the physis. Both patients with

apophysitis and avulsions fractures may

have tenderness and swelling at the site of

injury. However patients with apophysitis

usually do not have significant bruising or

ecchymosis. which may be present with

an acute fracture. Patients with an apoph-

yseal avulsion fracture should be able to

recall a specific event that triggered the

|iain compared to apophysitis. which has

a more insidious onset of pain.

IMAGINGA plain anteroposterior (AP) radio-

graph of the pelvis may demonstrate an

avulsed fragment (Figure 2). If the frac-

ture is not evident on the AP radiograph,

additional oblique or axial projections

may help delineate the fracture. How-

ever, these injuries are frequently missed

44 ORTHOPEDICS

APOPHYSEAL AVULSION FRACTURES OF THE Hl f AND PELVIS I MCKlNNEY ET AL

on initial radiographs. A computed to-mography (CT) scan is excellent for de-tailing bony anatomy and demonstratingLiny displaced fracture fragments (Figure3). Magnetic resonance imaging iTiay beuseful in evaluating apophysitis and avul-sions in children who ossification centerhas yet lo ossify (Figure 4). Recently, ul-trasound has been used to diagnose theseinjuries. In the hands of a skilled technolo-gist, ultrasound has been shown to he bothcost effective and accurate in diagnosingapophysea! avulsion fractures.'"

CLASSIFICATIONNo delinitive classification system exists

for all apophyseal avulsion fractures of thehip and pelvis. Classification of these in-juries is usually based on the location andamount of displacement. Torode and Zieg' 'classified all pédiatrie pelvis fractures. TypeI are avulsion fractures. Type II fracturesare iliac wing fractures. Type III fracturesinclude simple ring fractures. And type IVfractures are ring disruption fractures. Mar-tin iind Pipkin'- in 1957 classified ischialtuberosity avulsion fractures into 3 groups:nondisplaced fractures, acute avulsion frac-tures, and old nonunited fractures.

We propose a modification to Martinand Pipkin's classification to help guidetreatment options (Table I). The Martinand Pipkin classification was based on aspecific site of injury, the ischial tuheros-ity. and does not account for the amountof displacement. A classification systemthat accounts for displacement will aidthe physician in selecting the appropriatetreatment (Figure 5).

NONOPERATIVE TREATMENTNonoperativL' treatment has shown to

be succes.sful in many of these injuries.Metzmaker and Pappas' demonstratedsuccessful nonoperative treatment of 27avulsion fractures using a 5-phase proto-col (Table 2).

Stage Í consists of rest, cryotherapy,and the use of analgesics for the first weekafter the initial injury. Seven days after the

Type 1

Type II

Type Ml

Type IV

Toble 1

Classification of

\pophyseal Avulsion

Fractures

Nondispliiced fractures

Displacement up to 2 cm

Displütement >2 cm

Symptomatii: ni)nuninns orpainful exostosis

Figure 3; CT scan of the patient in Figure 2 demonstrates 8 mm of displacement. Conservative treatmentwas successful in this patient. Figure 4: MRI of a 13-year-olcl boy, who reported hip pain after kickinga ball, demonstrates increased signal around the anterior superior iliac spine suggesting an apophysealavulsion fracture (arrow). Conservative treatment was indicated in this minimaliy displaced fracture.

initial injury, the patient begins stage II,which consists of gentle active and passivemotion. Once 75% of motion is regained,the patient may progress to resistance ex-ercises. Stage UI consists of guided resis-tance exercises and typically begins two tothree weeks after initial injury. Stage IV.approximately I to 2 months after initialinjury, focuses on stretching and strength-ening with an emphasis on sports-specificexercises. Stage V is a return to competi-tive sports and should be started no earlierthan 2 months after the initial injury.

SURGICAL INOICATIONSMost authors agree that nonoperative

management with a guided rehabilitationprogram should be ihe initial option forpelvic avulsion fractures. However, sur-gical intervention has been indicated incertain instances. Sundiir and Carty" fol-lowed 22 patients with avulsion fracturesover 44 months. They found a limitationof sporting ability in 10 of the 22 patientswith persistent symptoms in 6 patients,mostly in those with ischial avulsion in-juries.'-' Many authors describe displace-ment of 2 to 3 cm as an indication for sur-gg^s.u-24 Painful nonunion, inability toreturn to competitive sports and exostosisformation are other indications (br surgi-cal intervention.'-''*''''^'^^ Other authorsfeel that any displaced greater trochanteravulsion fractures should be treated opera-tively due to the significant role of the ab-ductor musculature in both hip mechanicsand gait causing functional disability.^'^

The notion tliat open reduction and in-

Figure 5: 30 reconstructive CT scan of a 14-year-old boy, who reported groin pain while playingsports, demonstrates a displaced anterior inferioriliac spine avulsion fracture. Conservative treat-ment was successful in this patient.

temal fixation (ORIF) should be consideredfor fractures that are displaced >2 cm wasreported in a series of 5 pelvic avulsions andI case of bilateral tibial tubercle avulsions.-'Only 2 of the 5 cases presented were treatedoperatively. The authors" recommendationfor ORIF of fragments displaced > 2 cmwas only for ischiai avulsions.

Significantly displaced avulsion frag-ments raise 2 major concerns when con-sidering nonoperative treatment. The firstis whether the fragment will deveiop into a

JANUARY 2009 Volume 32 • Number 1 45

Review Article

1

Phase Postinjury (d)

1 0-7

II 7 to 14-20

III 14-20 to 30

IV 30-60

V 60 to return

Subjective Pain

Modérale

Minimal

Minimal wilhstress

None

None

Table 2

Physical Therapy Protocol

PalpationTenderness

Moclerale-severt

Moder.ite

Moderate

Minimal

None

Abbreviation: ROM. range of motion: WB. weight hearing.

ROM

Very limited

Improving withguided exercise

Improving withgentle stress

Normal

Normal

Mustie Strength

Poor

Fair

Good

Good-normal

Normal

Activity Level

None, protectedWB

Protected WB,guided exercise

Guided exer-cise, resistance

Limited athleticparticipation

Full activily

RadiographieAppearance

Osseous separa-tion

Osseous separa-tion

Early callus

Maturing callus

Maturing callus

Figure 5: Radiograph of a 13-year-old boy with an avulsion of the lesser trochanfer (arrow). Conservative treat-ment is indicated in these avulsion fractures unless painful nonunion or symptomatic exostosis develops.

nonunion because of the displacement. The

second major concern is the loss of strength

that may tx'cur from muscle shoitening.

Others argue that clinical experience with

patients who have had > 5 cm of shorten-

ing in muscle length for other reasons have

eventually regained muscle strength equiv-

alent to the contralateral .side. Throughout

the literature mainly isolated cases have

heen published in which a surgical decision

was made. Other authors have used the 2-

to 3-cm displacement criteria described

for ischial tuberosity avulsion fractures as

an indication for surgical intervention of

displaced anterior superior iliac spine and

anterior inferior iliac spine avulsions frac-

It is unclear in the literature whether

Surgical intervention allows a patient to

retum to high level sports sooner. Veseiko

and Smrkolj''' reported on 2 adolescent

athletes that underwent ORIF of the ante-

rior superior iliac spine. These 2 patients

were able to return to piny at 3 and 4 weeks

Irom the date of injury. Open reduction

and internal fixation may be advocated in

certain high end profession;il or collegiate

athletes for a shorter convalescence. How-

ever more studies are needed to determine

if high level athletes truly retum to sports

faster with operative intervention.

OPERATIVE TREATMENTLesser Trochanter, Iliac Crest, and PubicSymphysis

A review of the English-language litera-

ture revealed no case rcpoiis d(x:umenting

operative tjeatrnent of acute apopliyseal avul-

sion fracture of the lesser trochantei; iliac

crest or pubic symphysis in the adolescent

(Figure 6). Nonoperative treatment is i ec-

ommended for these injuries except Type IV

fractures (symptomatic nonunion or painful

exostosis). Small symptomatic nonunions

and painful exostosis should be excised and

the muscle reattached. Large avulsion non-

unions, >2 cm, should have nonunion repair

attempted with internal fixation. Tlie choice

of internal fixation would be de¡x:ndent on

the shape and location of the fragment.

ischial TuberosJtyRecently a case report for ORIF of

an ischial tuberosity avulsion sustained

in a jumping adolescent athlete was de-

46 ORTHOPEDICS I ORTHOSuperSite.com

APOPHYSEAL AVULSION FRACTURES OF THE HIP AND PELVIS I MCKINNEY ET AL

scribed.^'' The fracture was displaced 2.5

cm. The authors used a prone position and

a surgical approach through the gkiteal

crease and identified the plane between

ihe inferior border of the gluteus maximus

and the hamstrings. The fracture fragment

was identiiied at the proximal hatnstring

tendons and reduced with hip extension

and knee flexion. The fragment was stabi-

lized with 2 cancellous screws (4 and 6.5

mm) and washers. At 4 months postopera-

tively. the patient had resumed all normal

activity including playing rugby football.

At final follow-up, the patient was asymp-

tomatic and radiographs showed complete

healing of the fracture.

Greater TrochanterSeveral case reports have been pub-

lished documenting greater trochanter

avulsion fractures treated with surgical

fixation.^^ Mbubaeghu^ reported the ease

of a 14-year-old boy with a displaced

greater trochanter avulsion fracture who

underwent open reduction and internal

fixation. This fracture was fixed using a

single half-threaded cancellous screw.

The patient progressed to full weight

bearing at 4 weeks and recovery was

uneventful. O'Rourke and Weinstein^

describe a 13-year-old boy who under-

went closed reduction and percutaneous

cannulated screw fixation for a displaced

avulsion fracture of the greater trochan-

ter. At 8 months postoperative ly, the

patient developed worsening pain with

running. The patient was found to have

osteoneerosis of the entire femoral head

with collapse. Five years postoperatively,

the patient had mild-moderate pain. 20°

flexion contracture, limb-length discrep-

ancy of 1.5 cm and did not participate in

organized athletic activities. Woods et aV

describe a case report in which they use

a direct lateral approach to the greater

trochanter splitting the gluteus maximus.

For fixation, they used two 6.5-mm partial

threaded cancellous screws with washers,

According lo their case report, the patient

went on to an uneventful recovery.

Anterior Superior Iliac SpineThe anterior superior iliac spine can

be approached using a direct ineision over

the anterior aspect of the iliac crest. De-

pending on the fragment size 1 or 2 screws

with or with washers may be used. Use of

a tension band technique has also been de-

scribed in the treatment these fractures,'^

In a case series of 6 patients, Kosanovic et

al'^ describe a techniques of fixation us-

ing 2 Kirschner wires and a wire loop for

internal fixation. All 6 patients were able

to return to sports in 6 weeks.

Anterior inferior iliac SpineOne case report in the literature de-

scribes the operative treatment of an an-

terior inferior iliac spine avulsion frac-

ture with a modified Smith-Peterson

approach. ''' These authors used a 6.5 screw

with washer for fixation as well. One year

postoperatively, he was pain free, with full

leg strength and able to participate active-

ly in sport.

Postoperative ProtocoiMost authors recommend an initial pe-

riod of nonweight bearing (7-10 days) fol-

lowed by a period of progressive weight

bearing (3-6 weeks), and physical therapy.

Some authors allow return to sports at 4

to 6 weeks'^'^ while other authors recom-

mend return at 3 to 4 months''' postopera-

tiveiy.

CompijcationsMost apophyseal avulsion fractures

heal with excellent results. However therehave been a few documented complica-tions. The 2 most commonly reportedcomplications include painful nonunionand exostosis formaton.'^-^- Occasionallyfragmentation, lysis, or exostosis may oc-eur that can mimic many neoplastic andinfectious conditions.'-' If a painful non-union develops, it is generally recom-mended to treat these with operative fixa-tion. A symptomatic exostosis may requireexcision for resolution of symptoms. Themost severe complication that may arise

Table

indications for Operativeintervention

All Type IV alvusion fractures

Type III greater trochanter avulsionfractures

Type II & III ischial tuberosity avulsionfractures causing neurologic symptoms

Table 4

Reiative indications forOperative intervention

Type II greater troch.inler avulsionfractures

Type III ASIS, AIIS, and ischijl tuberos-ity avulsion fractures that have failedconservative treatment

Type III avulsion fractures in profes-sional or collegiate athletes

Abbreviations: AUS, anterior inferior iliacspine: ASÍS, anterior superior iliac spine.

is osteoneerosis of the femoral epiphysis

after avulsion of the greater trochanter.

Osteoneerosis has been reported in greater

troehanter avulsion fractures treated both

operative and nonoperatively.'' Displaced

ischial spine fractures have also been

found to cause seiatic nerve irritation

mimicking neurological pathology.-''"-'

CONCLUSiONApophyseal avulsion fractures of the

hip and pelvis are infrequent pédiatrie

fractures. However with increasingly ac-

tive children and adolescents in ttxlay's

population and better imaging techniques,

these fractures are becoming increasingly

more recognized. These fractures can be

easily missed. When these fractures are

diagnosed and treated appropriately, non-

surgical management is usually success-

ful. A 5-stage rehabilitation protocol has

been proposed in the literature and should

he the initial management for the majority

of these injuries. Multiple case reports and

case series document excellent results with

a guided nonoperative treatment protocoi.

IANUARY2009 Volume ,Î2 • Numher 1 47

Review Article

Based on our experience and review of

(he literature, we recommend the follow-

ing indications for treatment of apophyse-

al avulsion fractures of the hip and pelvis

(Tables 3. 4).

Surgical treatment should be used for

painful nonunions and symptomatic exos-

tosis {Type IV avulsion fractures). Any dis-

placed ischial tuherosity avulsion fracture

causing neurological symptoms should

be either excised with reattachment of

the hamstring tnusciilature (.small avuised

fragments) or undergo open reduction

and internal fixation (large fragments).

Significantly displaced greater trochanter

avulsion fractures (Type III) should be re-

duced and interna! tixation applied. This

is necessary to maintain proper tension on

the hip abductor complex and to prevent

a child or adolescent from developing a

trendelenburg gait.

A few relative indications exist for

operative treatment of apophyscal avul-

sions fractures. Greater trochanter avul-

sion fractures displaced < 2 cm (Type II)

may benefit from surgical fi.\ation lessen-

ing the chance of sequential di.splacement

and development of trendelenburg gait

due to abductor muscle shortening. This

area is controversial and further study is

needed in the treatment of these rare in-

juries. Good results have been reported in

the literature with operative treatment of

significantly displaced (Type Illj anterior

superior iliac spine, anterior inferior iliac

spine and ischial tuberosity avulsion frac-

tures. If a patient with I of these fractures

who has failed an initial period of conser-

vative treatment or is a profes.sional/col-

legiate high-end athlete, then surgical in-

tervention may be warranted.

Common complications of apophy-

seal avulsion fractures include painful

nonunion and exostosis. Regardless of

treatment, osteonecrosis may develop in

a patient with an apophyseal avulsion of

the greater trochanler. The treating physi-

cian mu.st counsel the patient and parents

on this possible complication. Numerous

case reports have documented neurologi-

cal symptoms with displaced ischiiil lu-

berosity fractures. If this occurs, surgical

treatment should he implemented.

With caieful understanding of the anat-

omy, mechanism of injury and treatment

options, these fractures can be success-

fully diagnosed and treated. Œ

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48 ORTHOPEDICS | oRTHosuperSite.com