Reliability of lower extremity alignment measurement using radiographs and PACS

Transcription

1 Knee Surg Sports Trumtol Arthrosc (2011) 19: DOI /s KNEE Reliility of lower extremity lignment mesurement using rdiogrphs nd PACS R. G. Mrx P. Grimm K. A. Lillemoe C. M. Roertson O. R. Ayeni S. Lymn E. A. Bogner H. Pvlov Received: 29 April 2010 / Accepted: 1 Mrch 2011 / Pulished online: 23 Mrch 2011 Ó Springer-Verlg 2011 Astrct Purpose Lower extremity lignment is n importnt considertion prior to crtilge surgery nd/or osteotomy out the knee. This is mesured on full length stnding hip to nkle rdiogrphs, which hs trditionlly een done using hrd copy rdiogrphs. However, the dvent of PACS (Picture Archiving nd Communiction Systems) R. G. Mrx (&) Sports Medicine nd Shoulder Service, Hospitl for Specil Surgery, 535 Est 70th St, New York, NY 10021, USA e-mil: mrxr@hss.edu P. Grimm K. A. Lillemoe Clinicl Reserch, Hospitl for Specil Surgery, 535 Est 70th St, New York, NY 10021, USA C. M. Roertson Orthopedic Surgery nd Sports Medicine, UCSD Medicl Center, Hillcrest, 200 West Aror Dr, Sn Diego, CA 92103, USA O. R. Ayeni Orthopedic Surgery nd Sports Medicine, McMster University Medicl Centre, 1200 Min St West, 4E17, Hmilton, ON L8N 3Z5, Cnd e-mil: ruffolo@mcmster.c S. Lymn Epidemiology nd Biosttistics, Hospitl for Specil Surgery, 535 Est 70th St, New York, NY 10021, USA e-mil: lymns@hss.edu E. A. Bogner H. Pvlov Rdiology nd Imging, Hospitl for Specil Surgery, 535 Est 70th St, New York, NY 10021, USA e-mil: ognere@hss.edu H. Pvlov e-mil: pvlovh@hss.edu hs llowed these mesurements to e done on computer sed digitl rdiogrphs. The ojectives of this study were to evlute the intr- nd inter-oserver reliility of lower lim lignment mesures mnully otined from hrd copy rdiogrphs versus using the Philips Esy Vision system, nd to ssess the sujective ese of use for the two methods. Methods Forty-two ptients who underwent surgery nd who hd stnding hip to nkle rdiogrph on file were identified. Four rters, including two rdiologists nd two orthopedic surgeons, mesured ech hrd copy rdiogrph nd computer imge on two seprte occsions. Three mesurements were recorded for ech hrd copy rdiogrph nd computer imge width of tiil plteu, the distnce from the medil spect of the tiil plteu to the weight-ering line, nd the mechnicl xis. Results All s for this study were high. For tiil plteu dt, the hrd copy rdiogrphs compred to PACS demonstrted intr-clss coefficients (ICC) rnging from 0.93 to 0.99 for inter-rter reliility for the four rters. The ICC for intr-rter reliility for hrd copies rnged from 0.90 to 0.99 nd for PACS from 0.94 to The inter-rter dt compring rters rnged from 0.87 to 0.98 for hrd copy rdiogrphs nd from 0.98 to 0.99 for PACS. For mechnicl xis dt, the ICC for hrd copy rdiogrph compred to PACS rnged from 0.93 to 0.97 for the intr-rter reliility for the four rters. The intr-rter reliility for mechnicl xis dt on hrd copy rdiogrph rnged from n ICC of 0.86 to 0.96, nd for PACS the ICC rnged from 0.93 to The inter-oserver dt for hrd copy rdiogrphs using the mechnicl xis rnged from 0.88 to 0.94 nd for PACS rnged from 0.93 to The physicins rted PACS s sttisticlly significntly esier to use when compred to hrd copy (P = 0.03).

2 1694 Knee Surg Sports Trumtol Arthrosc (2011) 19: Conclusion Evlution of lower extremity lignment using two techniques prior to knee surgery ws found to hve higher inter- nd intr-oserver reliility using PACS softwre. PACS is now used prior to crtilge surgery nd/or osteotomy to mesure oth lignment nd the loction of the weight ering line on the tiil plteu oth efore nd fter surgery. Level of evidence Dignostic study, Level I. Keywords Alignment Osteotomy PACS Surgery Mesurement Knee Introduction Lower extremity lignment is n importnt considertion prior to crtilge surgery nd/or osteotomy out the knee. This is mesured on full length stnding hip to nkle rdiogrphs. Trditionlly, these mesurements were otined using hrd copy rdiogrphs. With the dvent of PACS (Picture Archiving nd Communiction Systems), these mesurements cn e mde on computer sed digitl rdiogrphs using softwre pckges [2, 6]. Computer sed mesurements of digitl rdiogrphs present severl cler dvntges [1, 5, 9]. First, it elimintes the necessity of producing lrge, ulky hrd copy rdiogrphs, therey sving oth time nd money. Secondly, digitl rdiogrphs cn e retrieved nd stored with much greter ese thn hrd copy films. Finlly, mgnifiction nd contrst tools included in the softwre mke for esier mnipultion of the imge [7]. Wht is less well known is whether mesurements of lignment cn e mde on digitl rdiogrphs with the sme ccurcy s on hrd copy rdiogrphs. As result, some surgeons hve een reticent to emrce the use of this new technology for pre-opertive plnning. A previous study nlyzed the greement etween hrd copy rdiogrph mesurements nd those mde using the softwre pckge HTO Pro [8]. To the uthors knowledge, no study hs compred hrd copy rdiogrph mesurements nd those mde using the PACS Esy Vision system. The ojective of this study ws to evlute the intr- nd inter-oserver reliility of lower lim lignment mesures mnully otined from hrd copy rdiogrphs versus mesurements otined using the Philips Esy Vision system. A secondry ojective ws to ssess the sujective ese of use for the two methods. The hypothesis ws tht digitl rdiogrphs would hve similr reliility to hrd copy rdiogrphs for the mesurement of lower extremity lignment. Mterils nd methods Forty-two ptients (17 women nd 25 men; 21 left knees nd 21 right knees) who underwent surgery nd who hd Fig. 1 Hip center (H) Fig. 2 Knee center (K) stnding hip to nkle rdiogrph on file were identified. The procedures include fourteen high tiil osteotomies, nine mosicplsties, seven meniscl llogrfts, five microfrctures, four osteochondrl llogrfts, nd three primry OBI mosicplsties. Hrd copy rdiogrphs were then orgnized lpheticlly nd leled y study numer. The ptient nme ws covered to prevent the rters from identifying the ptient. Four rters, including two rdiologists nd two orthopedic surgeons, mesured ech hrd copy rdiogrph nd computer imge (using the Philips Esy Vision system) on two seprte occsions seprted y minimum of 2 weeks. The presenttion order of the rdiogrphs ws chnged etween the first nd second redings to further minimize recll is. Three mesurements were recorded

3 Knee Surg Sports Trumtol Arthrosc (2011) 19: Fig. 3 Ankle center (A) Distnce from medil spect of tiil plteu to weight- Width of Tiil Plteu Fig. 4 Mesurement of percent cross tiil plteu % Across Tiil Plteu 42.2 / 75.6 = 55.8% for ech hrd copy rdiogrph nd computer imge width of tiil plteu, the distnce from the medil spect of the tiil plteu to the weight-ering line, nd the mechnicl xis. The following points were used to conduct ll mesurements: Center of Hip (H) Center of femorl hed, in est judgment of the oserver (Figs. 1, 5). Center of Knee (K) Midpoint of the tiil spines hlfwy etween the intercondylr notch (Figs. 2, 5). Center of Ankle (A) Midpoint etween inner edges of mlleoli, height of tlus [Figs. 3, 5]. Fig. 5 Exmple of the clcultion of mechnicl xis The following mesurements were mde on oth hrd copy rdiogrphs nd digitl imges: 1. Percent Across Tiil Plteu Mesured in the following mnner: i. Drw weight-ering line from hip center (H) to nkle center (A). ii. Mesure width of Tiil Plteu t its widest point (Fig. 4). iii. Mesure distnce from medil spect of the tiil plteu to the intersection with the weight-ering line. If the weight-ering line flls to the medil side of the joint, the distnce is mesured s negtive distnce. Formul = [(Distnce from Medil Aspect of Tiil Plteu)/(Width of Tiil Plteu (mm))] * Mechnicl Axis Mesured in the following mnner: i. Drw Femorl Mechnicl Axis from hip center (H) to knee center (K). ii. Drw the Tiil Mechnicl Axis from the nkle center (A) to knee center (K). iii. Mesure the ngle etween the Femorl Mechnicl Axis nd the Tiil Mechnicl Axis. This is known s the mechnicl xis of the lower lim [2]. Express s its ngulr devition from 180. Vrus devitions re negtive. Vlgus devitions re positive (see Fig. 5).

4 1696 Knee Surg Sports Trumtol Arthrosc (2011) 19: Tle 1 Tii plteu dt HC versus PACS Rdiologist A Rdiologist B Orthopod A Orthopod B Scle % cross tii plteu Tle 2 Tii plteu dt HC intr-rter Rdiologist A Rdiologist B Orthopod A Orthopod B PACS intr-rter Rdiologist A Rdiologist B Orthopod A Orthopod B Scle % cross tii plteu For hrd copy rdiogrphs, shrpened soft led film mrking pencil ws used for ll mesurements. These mrkings were ersed fter ech mesurement. A strightedge ws used to mrk the weight-ering line, femorl mechnicl xis, nd tiil mechnicl xis. A trnsprent metric ruler with millimeter mrkings ws used to mesure tiil width nd the distnce from the medil spect of the tii to the weight-ering line. A goniometer (Whitehll Mnufcturing, Model G300) ws used to mesure the ngle etween the mechnicl xis of the femur nd the mechnicl xis of the tii. For computer imges, ll rdiogrphs were loded onto the Philips Esy Vision system t the time they were produced. Using the tools provided in this system, clinicins cn mesure distnces, ngles, nd digitlly mrk ntomicl lndmrks. The sme mesurements s descried ove were mde using these tools. Sttisticl nlysis Inter- nd intr-rter reliility were mesured using one wy rndom single mesure intrclss coefficients (ICCs) with ssocited 95% confidence intervls to guge the precisions of the ICCs. Reviewers were not pooled for this nlysis in order to evlute individul inter-rter reliility, especilly in exmining differences etween rdiologists nd orthopedic surgeons. All nlyses were conducted using SPSS for windows 17.0 (Chicgo, IL). Ech of the four rters ws lso sked to rte the ese of use of the two methods on Likert Scle rnging from Tle 3 Tii plteu dt HC inter-rter Rdiologist A versus Rdiologist B Orthopod A versus Orthopod B Rdiologist A versus Orthopod A Rdiologist A versus Orthopod B Rdiologist B versus Orthopod A Rdiologist B versus Orthopod B PACS inter-rter Scle % cross tii plteu Rdiologist A versus Rdiologist B Orthopod A versus Orthopod B Rdiologist A versus Orthopod A Rdiologist A versus Orthopod B Rdiologist B versus Orthopod A Rdiologist B versus Orthopod B

5 Knee Surg Sports Trumtol Arthrosc (2011) 19: Tle 4 Mechnicl xis dt HC versus PACS Rdiologist A Rdiologist B Orthopod A Orthopod B Tle 5 Mechnicl xis dt HC intr-rter Rdiologist A Rdiologist B Orthopod A Orthopod B PACS intr-rter Rdiologist A Rdiologist B Orthopod A Orthopod B one to ten, with one eing very difficult nd ten eing very esy. Results All s for this study were high. The results were divided into mechnicl xis dt nd tiil plteu dt. For tiil plteu dt, the hrd copy rdiogrphs compred to PACS demonstrted intr-clss coefficients (ICC) rnging from 0.93 to 0.99 for inter-rter reliility for the four rters (see Tle 1). The ICC for intr-rter reliility for hrd copies rnged from 0.90 to 0.99 nd for PACS from 0.94 to 0.99 (see Tle 2, ). The inter-rter dt compring rters rnged from 0.87 to 0.98 for hrd copy rdiogrphs nd from 0.98 to 0.99 for PACS (see Tle 3, ). For mechnicl xis dt, the ICC for hrd copy rdiogrph compred to PACS rnged from 0.93 to 0.97 for the intr-rter reliility for the four rters (see Tle 4). The intr-rter reliility for mechnicl xis dt on hrd copy rdiogrph rnged from n ICC of 0.86 to 0.96 nd for PACS the ICC rnged from 0.93 to 0.99 (see Tle 5, ). The inter-oserver dt for hrd copy rdiogrphs using the mechnicl xis rnged from 0.88 to 0.94 nd for PACS rnged from 0.93 to 0.97 (see Tle 6, ). The physicins rted PACS s sttisticlly significntly esier to use when compred to hrd copy (P = 0.03). The medin rting for PACS ws 10 (rnge ). For hrd copy, the medin ws 4 (rnge 2 6). Tle 6 Mechnicl xis dt HC inter-rter Rdiologist A versus Rdiologist B Orthopod A versus Orthopod B Rdiologist A versus Orthopod A Rdiologist A versus Orthopod B Rdiologist B versus Orthopod A Rdiologist B versus Orthopod B PACS inter-rter Rdiologist A versus Rdiologist B Orthopod A versus Orthopod B Rdiologist A versus Orthopod A Rdiologist A versus Orthopod B Rdiologist B versus Orthopod A Rdiologist B versus Orthopod B

6 1698 Knee Surg Sports Trumtol Arthrosc (2011) 19: Discussion The present study demonstrted tht oth PACS nd hrd copy rdiogrphs were highly relile in the mesurement of lower extremity lignment. Preopertive plnning for crtilge surgery nd/or osteotomy out the knee hs trditionlly used long leg rdiogrphs mesured on inch cssettes. This is specilized rdiogrph requiring specific equipment nd long view ox to evlute the film. With the dvent of PACS, rdiogrphs cn e rchived digitlly with greter ese, nd mesurements cn e mde directly on the film using stndrd PACS softwre. Surgeons t the uthors institution hve een reluctnt to move wy from the hrd copy rdiogrphs due to fmilirity. This study ws performed to evlute whether the intr- nd inter-oserver reliility using long leg lignment rdiogrphs ws dequte using PACS mesurements compred to the stndrd technique using pencil nd long leg, hrd copy rdiogrph. The results demonstrte very high ICC for oth introserver nd inter-oserver reliility. The lowest ICC mesured ws 0.86 (95% confidence intervl ) for the intr-rter of one oserver using hrd copy rdiogrphs. This ICC is cceptle for intr-oserver reliility [4]. Furthermore, the PACS intr- nd inter-oserver reliility ws slightly higher overll thn it ws for hrd copy rdiogrphs, lthough this ws not evluted for sttisticl significnce. PACS ws found to e esier to use when mesuring lignment, with ech physicin rting in fvor of PACS y minimum of 4 points on 10 point rting scle. Limittions of this study include the fct tht the rdiogrphs were evluted consecutively y the clinicins in n rticificil setting. However, there should not hve een ny is relted to mrkings on the rdiogrphs or on the computer screen, since oth were completely ersle, or removle in the cse of the computer grphics. The clinicl relevnce of this work is tht clinicins cn now utilize PACS to mesure long leg lignment rther thn otining long hrd copy views, which re more difficult to mnge nd costly. In summry, evlution of lower extremity lignment using two techniques prior to knee surgery ws found to e cceptle using PACS softwre. Hrd copy rdiogrphs re therefore not required for improved ccurcy. PACS is now used prior to crtilge surgery nd/or osteotomy to mesure oth lignment nd the loction of the weight ering line on the tiil plteu oth efore nd fter surgery. Conclusion PACS should e used rther thn hrd copy rdiogrphs, ecuse the reliility is t lest equl, nd PACS is esier to work with. Acknowledgments The uthors cknowledge the contriutions of John Cvnugh, Li Foong Foo, Jo Hnnfin, Hollis Potter, Scott Rodeo, Russell Wrren, Thoms Wickiewicz nd Riley Willims to the development of this study. References 1. Cho EYS, Sim FH (1995) Computer-ided preopertive plnning in knee osteotomy. Iow Orthop J 15: Hnkemeier S, Gosling T, Richter M, Hufner T, Hochhusen C, Krettek C (2006) Computer-ssisted nlysis of lower lim geometry: higher introserver reliility compred to conventionl method. Comput Aided Surg 11: Hsu RW, Himeno S, Coventry MB, Cho EY (1990) Norml xil lignment of the lower extremity nd lod-ering distriution t the knee. Clin Orthop Relt Res 255: Mrx RG, Jones EC, Allen AA, Altchek DW, O Brien SJ, Rodeo SA, Willims RJ, Wrren RF, Wickiewicz TL (2001) Knee outcome scles for thletic ptients. J Bone Joint Surg Am 83: Prksh U, Wigderowitz CA, McGurty DW, Rowley DI (2001) Computerised mesurement of tiiofemorl lignment. J Bone Joint Surg Am 83: Siler J, Schritzer M, Peloschek P, Giure A, Imhof H, Grmpp S (2005) Quntifiction of xil lignment of the lower extremity on conventionl nd digitl totl leg rdiogrphs. Eur Rdiol 15: Sled EA, Sheehy LM, Felson DT, Costign PA, Lm M, Derek T, Cooke V (2011) Reliility of lower lim lignment mesures using n estlished lndmrk-sed method with customized computer softwre progrm. Rheumtol Int 31: Specogn AV, Birminghm TB, DSilv JJ, Milner JS, Kerr J, Hunt MA, Jones IC, Jenkyn TR, Fowler PJ, Giffin JR (2004) Reliility of lower lim frontl plne lignment mesurements using plin rdiogrphs nd digitized imges. J Knee Surg 17: Tkhshi T, Ymnk N, Komtsu M, Ogw Y, Yoshid S, Ymmoto H (2003) A new computer-ssisted method for mesuring the tiio-femorl ngle in ptients with osteorthritis of the knee. Osteorthr Crtil 12: