8162019 Tauntonearlypostoperativefemurfractureafteruncementedcollarlessprimarytha

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Early Postoperative Femur Fracture After Uncemented Collarless Primary

Total Hip Arthroplasty Characterization and Results of Treatment

Michael J Taunton MD a Lawrence D Dorr MD b William T Long MD bManish R Dastane MD b Daniel J Berry MD a

a Mayo Graduate School of Medicine Mayo Clinic Rochester Minnesotab Arthritis Institute Centinela Hospital Medical Center Inglewood California

a b s t r a c ta r t i c l e i n f o

Article historyReceived 27 January 2015

Accepted 20 May 2015

Available online xxxx

Keywords

postoperative

THA

uncemented

outcomes

primary

Thirty Vancouvertype B periprosthetic fractures occurred within 90 days of total hiparthroplastywere identi1047297edusing two institutional databases Twenty-eight of these fractures were of a stereotyped fracture pattern

consisting of a displaced fracture of the femoral neck including the lesser trochanter and a variable amount of

the proximal medial femoral cortex creating a roughly triangular fragment Time from operation until fracture

was 2ndash88 days (mean 28) Mechanism of injury was fall from standing height in 12 no de 1047297ned trauma in 11

stumble without fall in 5 and twisting motion in 2 Fracture treatment consisted of femoral revision in 24

fracture 1047297xation in two and nonoperative in four Of the 24 treated with revision 21 had healed fractures and

stable revision stems

copy 2015 Elsevier Inc All r ights reserved

As uncemented total hip arthroplasty (THA) has come into more

common use data from several national joint registries and other

sources have suggested that early periprosthetic femur fractures afterprimary uncemented THA are one of the most frequent early modes of

implant failure and one of the most common complications leading to

early revision [1ndash3] The purpose of this study was to characterize

early periprosthetic femur fractures after uncemented primary THA

with respect to fracture pattern frequency circumstances of occur-

rence and outcome of treatment The fractures uniquely strongly asso-

ciated with uncemented primary THA are the Vancouver Type B

fractures and hence these fractures are the focus of this report

Materials and Methods

Between January 1987 and December 2007 19271 consecutive pri-

mary total hip arthroplasties were performed at the authors rsquo two insti-

tutions of which 7447 were performed utilizing an uncemented

proximally porous coated collarless femoral component Over this

time period stems of many designs were implanted at the two institu-

tions and stem design was chosen at the discretion of the surgeon

The computerized databases of the authorsrsquo two institutions wereused to identify all periprosthetic femur fractures occurring within

90 days of implantation of an uncemented proximally porous coated

collarless femoral component between 1987 and 2007 Exclusion

criteria included patients with a previous surgical procedure to the

proximal femur or a previous proximal femur fracture The study was

approved by the Institutional Review Boards of both institutions

The preoperative postoperative fracture and latest followup radio-

graphs of allhips that sustained a fracture were evaluated by two of the

authors (DJB and MJT) Bone morphology was assessed on the preoper-

ative radiographs according to the criteria of Dorr [4ndash6] Fractures

were classi1047297ed according to the Vancouver system described by Duncan

and Masri [7] This classi1047297cation system has been validated and

shown to have high intraobserver and interobserver reliability [8]

At the authorsrsquo two institutions it is routine to obtain postoperative

anteroposterior and lateral radiographs immediatelyafter the operation

on theday of surgery All radiographs were con1047297rmed to have no visible

fracture on immediate postoperative radiographs

Operative reports and clinical notes were reviewed to correlate clin-

ical factors Patients with a fracture identi1047297ed intraoperatively were ex-

cluded Data from the early postoperative period were reviewed and

recorded including the patientsrsquo location at the time of fracture (hospi-

tal rehabilitation facility or at home) the patientsrsquo weight bearing sta-

tus rehabilitation protocol support used at the time of fracture (walker

cane or crutches) and activity at time of fracture event Clinical data re-

garding outcome of the fracture and its treatment were collected at the

time of most recent followup evaluation

The Journal of Arthroplasty xxx (2015) xxxndashxxx

Oneor more ofthe authors ofthis paper havedisclosedpotential orpertinentcon1047298icts

of interest which may include receipt of payment either direct or indirect institutional

support or association with an entity in the biomedical 1047297eld which may be perceived to

have potential con1047298ict of interest with this work For full disclosure statements refer to

httpdxdoiorg101016jarth201505044

Source of Funding There was no external funding for this study

ReprintrequestsDaniel J Berry MD Mayo Clinic200 First Street SWRochester MN

55905

httpdxdoiorg101016jarth201505044

0883-5403copy 2015 Elsevier Inc All rights reserved

Contents lists available at ScienceDirect

The Journal of Arthroplasty

j o u r n a l h o m e p a g e w w w a r t h r o p l a s t y j o u r n a l o r g

Please cite thisarticle as Taunton MJ et al Early Postoperative Femur Fracture After Uncemented Collarless Primary Total Hip Arthroplasty Char-acterization and Results of Tre J Arthroplasty (2015) httpdxdoiorg101016jarth201505044

8162019 Tauntonearlypostoperativefemurfractureafteruncementedcollarlessprimarytha

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The 1047297xation of cemented stems after revision was assessed accord-

ing to the criteria of Harris et al [9] The 1047297xation of uncemented

stems after revision was assessed according to the method of Engh

and Massin [10]

Statistical Analysis

All statistical analyses were performed with two-tailed tests The

level of signi1047297cance was set at P b 005

Results

Vancouver type B femur fractures were identi1047297ed to have occurred

in the 1047297rst 90 days after THA in 30 hips (30 patients) among the 7447

hips for an incidence of 04 There were 18 females and 12 males

with a mean age of 63 years (range 25ndash84 years) The mean body

mass index was 31 (range 21ndash46) Arthroplasty approach was posterior

in 16 (minimally invasive in 5) anterior in 11 transtrochanteric in one

and two-incision minimally invasive in 2 Eleven fractures involved the

left hip and 19 involved the right hip The primary operative diagnosis

was osteoarthritis in 25 hips osteonecrosis of the femoral head in two

hips posttraumatic arthritis in two hips and rheumatoid arthritis in

onehip Fifteen patients had Dorr type ldquoArdquo proximal femoral bonemor-

phology and 15 had type ldquoBrdquo bone

There were four different stem types studied making up the 7447

stems The Hydroxyapatite Proxilock (Zimmer Warsaw Indiana) was

inserted in 662 pts with 11 fractures (16 fracture rate) APR (Zimmer

Warsaw IN) in 3422 pts with10 fractures (01 fracture rate) Omni1047298ex

(Stryker Kalamazoo MI) in 942 patients with 4 fractures (04 fracture

rate) Summit (Depuy USA) in 1208patients with 3 fractures(03 frac-

ture rate) and Secur-Fit Hydroxyapatite (Stryker Kalamazoo MI) in

1213 patients with 2 fractures (02 fracture rate)

The mean time between the arthroplasty and fracture was 28 days

(range 2ndash88 days) The mechanism of injury consisted of a fall from

standing height in 12 patients no de1047297ned trauma in 11 patients a trip

or stumble in 1047297ve patients and twisting at the hip in two patients At

time of fracture 20 patients were still using arm support to ambulate

Twelve patients were using a walker 7 were using crutches and 1was using a cane Nineteen patients had been instructed that they

could weight bear as tolerated on the operative limb at the time of frac-

ture and 11 had been instructed to be partial weight bearing with arm

support at the time of fracture

In 28 hips the femur fracture was of a stereotyped pattern consisting

of a fracture of the femoral neck and proximal medial femur which

exited through the medial cortex creating a roughly triangular fracture

fragment that included the lessertrochanter (Figs 1 and 2) Theaverage

distance below the lesser trochanter that the fracture exited the medial

cortex was 37 cm (range 0ndash11 cm) In two of these 28 hips in which

this same fracture pattern was con1047297rmed at the time of reoperation

there was notable sudden stem subsidence but the fracture lines were

not visible on the radiographs Two hips had Vancouver typeB proximal

femur fractures that exited through the lateral cortex below the level of the lesser trochanter rather than medially

Fracture treatment consisted of reoperation with femoral compo-

nent revision and fracture stabilization in 24 hips reoperation with

stem retention and fracture stabilization in 2 and nonoperative treat-

ment in 4 Twelve femoral components were revised to an extensively

porous coated uncemented stem 6 were revised to a 1047298uted-tapered

modular uncemented stem (Fig 2) 3 were exchanged for a larger

stem of the same design and three were revised to a cemented stem

The average duration of followup after fracture was 45 months

(range 3ndash219 months) The average preoperative Harris Hip score was

42 (range 13ndash67) This improved to an average postoperative Harris

Hip score of 76 (range 32ndash100) at latest followup

At latest followup the 4 femur fractures that were selected for non-

operative treatment had healed and the implants were radiographically

stable The 2 femurs that were selected for treatment with internal

1047297xation and stem retention also healed and the implants were

radiographically stable at latest followup Twenty-one of 24 fractures

treated with femoral component revision healed and had a stable

femoral component at latest followup Two of the 24 patients treated

with femoral revision developed prosthetic infection and had further

procedures (Fig 3) and one of the 24 patients treated with femoral

revision developed femoral component loosening and had another

femoral revision

Discussion

Early periprosthetic femur fracture after primary uncemented THA

recently has been shown to be a leading reason for early revision after

THA in large national joint registry databases [1ndash3] Little is known

about the fracture patterns clinical circumstances and results of treat-

ment when these fractures occur in contemporary practice Theprimary

purpose of this paper was to characterize the pattern and clinical

circumstances surrounding these fractures when they occur in conjunc-

tion with a commonly used class of uncemented femoral componentsmdashcollarless uncemented stems A secondary goal was to report early re-

sults of treatment

Twenty-eight of the 30 Vancouver type B fractures in this report

were of a single stereotypical pattern characterized by a separate frag-

ment of posterior medial cortical bone that included the lesser trochan-

ter We classi1047297ed these fractures as Vancouver type B periprosthetic

femur fractures rather than Vancouver A(L) fractures which are de-

scribed as avulsion fractures of the lesser trochanter The fractures de-

scribed in this report typically were associated with stem subsidence

and stem rotation to a relatively retroverted position Because the frac-

ture is usually associated with loss of implant 1047297xation in addition to

change in implant position acute reoperation typically is indicated

We hypothesize that early fractures of this pattern in association

with proximally porous coated uncemented femoral components may

Fig 1 (A) Immediate postoperative hip radiograph of a 71 year old woman after

uncemented THA (B) Radiograph 12 days postoperatively after the patient fell at home

while weight bearing as tolerated demonstrating fracture

2 MJ Taunton et al The Journal of Arthroplasty xxx (2015) xxxndash xxx

Pleasecite this article as Taunton MJet al Early Postoperative Femur Fracture After Uncemented CollarlessPrimary Total Hip Arthroplasty Char-acterization and Results of Tre J Arthroplasty (2015) httpdxdoiorg101016jarth201505044

8162019 Tauntonearlypostoperativefemurfractureafteruncementedcollarlessprimarytha

httpslidepdfcomreaderfulltauntonearlypostoperativefemurfractureafteruncementedcollarlessprimarytha 34

occur as the result of two separate circumstances In some cases these

postoperatively-recognized fractures may represent propagation and

displacement of an unrecognized minimally displaced intraoperative

crack In other cases these fractures may represent a new fracture

which occurs due to high axial and torsional loads being placed on the

uncemented implant as the result of a stumble or fall before the

wedge-shaped collarless implant has become osteointegrated into

the bone

The proximally porous coated tapered stems used by surgeons in

this study were all of the 3 dimensional taper designs The broaching

for these stems provides a slightly smaller space than the size of the ac-

tual stem As the 1047297nal stem is impacted hoop stresses occur The visco-

elastic nature of the bone allows for creep and stress relaxation of the

bone [11] As the press-1047297t lessens with relaxation the high roughness

of the porous surface the tapered design and perhaps 3-point 1047297xation

provide further initial stability The mechanical properties of these ta-pered stems then translate to working best in proximal femoral mor-

phology with these tapered medullary shapes allowing for maximal

implantndashbone contact For patients with weak proximal femoral bone

that does not provide reliable 1047297xation of an uncemented implant or

that may be at high risk for fracture cemented femoral component 1047297x-

ation with optimal implant designs can provide a high rate of success

Rapid mobilization of patients with early full weight bearing has be-

come common place and with early mobilization in the postoperative

period patients may be more likely to fall stumble or otherwise place

very high loads on the hip leading to a displaced fracture Hip

arthroplasty through smaller incisions has become common and small-

er incisions may make it dif 1047297cult for a surgeon to identify an intraoper-

ative fracture and treat it intraoperatively

In most cases in this report the fracture wastreated with reoperationconsisting of femoral component revision and fracture stabilization

with cerclage because in most cases the femoral component had lost

1047297xation subsided andor become retroverted as a consequence of

these fractures Two cases were successfully treated withfracture stabi-

lization without revision Intraoperatively it is essential to assess stem

stability and unless the stem is unquestionably stable axially and

rotationally the stem should be revised especially in this early postop-

erative circumstance before the stem is bone ingrown In the few cases

in this report in which the implant appeared to remain stable and in a

satisfactory position nonoperative treatment was successful The

early outcome of fracture treatment was favorable in the majority of

these 30 hips Nevertheless it is important to emphasize that all

patients suffered the morbidity associated with either operative or

nonoperative treatment of the fracture and in a several patients the

Fig 2 (A)Immediate postoperative radiographof an 84 yearold manafteruncemented THA(B) Radiograph 27 dayspost-operatively after thepatient hadincreasedpainat rehabilitation

facility while using a walker ambulating weight bearing as tolerated (C) Radiograph after revision to a 1047298uted tapered modular stem

Fig 3 (A) Immediate postoperative hip radiograph of a 70 year old woman after

uncemented THA (B) Radiograph 10 days postoperatively demonstrating periprosthetic

fracture and hip dislocation (C) Radiograph after revision to 1047298uted tapered stem

(D) Radiograph after component resection for infection following revision operation

3MJ Taunton et al The Journal of Arthroplasty xxx (2015) xxxndash xxx

Please cite thisarticle as Taunton MJ et al Early Postoperative Femur Fracture After Uncemented Collarless Primary Total Hip Arthroplasty Char-acterization and Results of Tre J Arthroplasty (2015) httpdxdoiorg101016jarth201505044

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fracture was the beginning of a cycle of further complicationsleading to

notable morbidity

By making surgeons aware of clinical circumstances associated with

early periprosthetic femur fracture the authors hope some such frac-

tures may be avoided in the future Careful consideration may be

given to the indications for use of these categories of femoral compo-

nents in patients considered at high risk for fracture due to poor bone

quality Selected patients so treated but considered at higher risk for

fracture may be treated with prophylactic intraoperative cerclage with

a wire or cable just above the lessertrochanter Thorough intraoperative

scrutiny of the femoral neck after implant placement may identify some

nondisplaced fractures and allow intraoperative treatment with

cerclage 1047297xation Careful consideration may be given to judicious use

of arm support for a period of time after surgery in patients at risk for

a stumble or fall which might precipitate a displaced fracture And1047297nal-

ly patient education about fracture risk may encourage caution to avoid

circumstances that could lead to stumble or fall in the early postopera-

tive time period

References

1 Havelin LI The Norwegian Joint Registry Bull Hosp Jt Dis 199958(3)1392 National Joint Registry forEngland andWales 9thannual report2012 [httpwwwhqip

orgukassetsNCAPOP-LibraryNCAPOP-2012-13NJR-9th-Annual-Report-2012pdf ]3 Australian Orthopaedic Association National Joint Replacement Registry annual re-

port 2014 [httpaoanjrrdmacadelaideeduaudocuments10180172286Annual20Report202014]

4 Dorr LD Absatz M Gruen TA et al Anatomic porous replacement hip arthroplasty1047297rst 100 consecutive cases Semin Arthroplasty 19901(1)77

5 Dorr LD Faugere MC Mackel AM et al Structural and cellular assessment of bone

quality of proximal femur Bone 199314(3)2316 Dossick PH Dorr LD Gruen T Saberi MT Techniques for pre-operative planning and

post-operative evaluation of non-cemented hip arthroplasty Tech Orthop 1991617 DuncanCP MasriBAFractures ofthe femurafter hipreplacementInstrCourse Lect1995442938 Brady OHGarbuzDS Masri BAet alThe reliabilityand validityof theVancouver clas-

si1047297cation of femoral fractures after hip replacement J Arthroplasty 200015(1)599 Harris WH McCarthy Jr JC ONeill DA Femoral component loosening using contem-

porary techniques of femoral cement 1047297xation J Bone Joint SurgAm 198264(7)106310 Engh CA Massin P Cementless total hip arthroplasty using the anatomic medullary

lockingstem Resultsusing a survivorship analysis ClinOrthop Relat Res 1989(249)14111 Mallory TH Head WC Lombardi Jr AV Tapered design for the cementless total hip

arthroplasty femoral component Clin Orthop Relat Res 1997433172

4 MJ Taunton et al The Journal of Arthroplasty xxx (2015) xxxndash xxx

Pleasecite this article as Taunton MJet al Early Postoperative Femur Fracture After Uncemented CollarlessPrimary Total Hip Arthroplasty Char-acterization and Results of Tre J Arthroplasty (2015) httpdxdoiorg101016jarth201505044