C l i n i c a l R e s e a r c h A n k l e S iz e M e a s u r e m e n t s w i t h t h e F o o t i n a F r e e H a n g i n g P o s i t i o n Reliability o f the Figure-of-Eight Tape Method A B ST R A C T : Ankle swelling is a commonly encountered condition in physiotherapy practice. Reliable and easy methods o f quantification are required to record progress in treatment. The aim o f this study was to establish the inter- and intra-reliability o f the figure-of-eight tape measure fo r measuring ankle size. Thirty - six healthy subjects were measured in long-sitting position with the fo o t hanging free over the edge o f a plinth. Three testers performed fo u r measurements each fo r a total o f 12 measurements p er subject. The intra-class correlation coefficient was 0.96 fo r inter-tester reliability and 0.94 fo r intra-tester reliability. The results agree with previous reli­ ability studies using the figure-of-eight tape method on healthy subjects. The figure-of-eight tape method is easily learned and applied. It is a reliable method fo r measuring ankle size. Further research is needed to demonstrate the reliability and validity o f the technique in a clinical setting. K E Y WORDS: RELIABILITY, POSITIONING, ANKLE SIZE MEASUREMENTS GUY VAN HERP TALAL AL SHATl'l INTRODUCTION P o st-trau m atic ankle sw ellin g is a co m m o n co n d itio n e n co u n te re d by physiotherapists in daily clinical p rac­ tice. Sportsm en are especially prone to these kind o f injuries although protective devices and taping play an im portant p re­ v en tiv e ro le (P eterson & R e n stro m , 1986). In addition, ankle sw elling can often occur as a com plication after cast im m obilisation for traum a o f the low er legs (A iraksinen e ta l., 1991). T he aetiol­ ogy o f sw ellin g is p ro b ab ly m u lti­ factorial, including increased capillary filtration and reduced lym phatic drainage resulting from soft tissue traum a to lym ­ p h atic v essels (S tra n d en & M yhre, 1981). Sw elling is one o f the cardinal signs o f acute inflam m ation and is m ostly associ­ ated with haem orrhage, heat and pain. O f these signs, sw elling is the m ajor cause o f fu nctional disability follow ing the injury (N ilsson, 1981). R egular m easure­ m ent o f jo in t sw elling is required to p ro ­ vide the therapist with objective reco rd ­ ings with w hich to plan or alter the reha­ bilitation program . In clinical practice ankle sw elling is often evaluated by vol­ um etry, o r w a ter p leth y sm o g rap h y . C O R R E SPO N D EN C E G U Y VAN H ER P M Sc Q ueen M argaret College, Physiotherapy D epartm ent, Leith Cam pus, D uke Street, E dinburgh EH 6 8H F Scotland. Tel: 0131 3173663 Fax: 0131 317 3308 TA LA L A L S H A T T I BSc K uw ait O il Company, A hm adi, K uw ait. N ilsson (1981) stated that volum etry is a valid m ethod for evaluation o f sw elling in the ankle and foot. H ow ever, no relia­ bility studies have been found in the lit­ erature. Furtherm ore, volum etry proves to be an im practical m ethod and alternate less cum bersom e m ethods are required in clinical practice. O ther m ethods o f m ea­ suring sw elling regularly used in the clin­ ic include circum ferential m easurem ents obtained through the use o f standard tape m easure, or using callipers across the m alleoli (Esterson, 1979). M easurem ents across the m alleoli have the disadvantage that they do not usually m easure sw elling resulting from ankle sprains because the m easuring d evice does not cross the in ju red structu re. T h e fig u re-o f-eig h t tape m ethod is another com m only used procedure. It is easily reproduced by using bony landm arks around the ankle. T his tape m ethod used m easurem ents across several com m on sites o f ankle sprains and proved to be m ore valid then other circum ferential m easurem ents. The m ethod proved to be both reliable and practical (Tatro-A dam s et al., 1995). In the above study, m easurem en ts w ere obtained at jo in t ankles o f neutral dorsi- flexion as described by E sterson (1979). In this position the dorsiflexor muscles are in a shortened position and tendons F igure 1: The fig u re-o f-eig h t m ethod o f a nkle m easurem ent 14 SA J o u r n a l o f P h y s io th e r a p y 1998 V o l 54 No 1 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) TABLE 2: INTRA-TESTER CORRELATION - CORRELATION MATRIX Tester 1 Measurement 1 Measurement 2 Measurement 3 Measurement 2 0.95 Measurement 3 0.95 0 .9 7 Measurement 4 0.94 0.96 0.98 Tester 2 Measurement 1 Measurement 2 Measurement 3 Measurement 2 0.96 Measurement 3 0.96 0.96 Measurement 4 0.95 0.96 0 .9 7 Tester 3 Measurement 1 Measurement 2 Measurement 3 Measurement 2 0.95 Measurement 3 0.92 0.91 Measurement 4 0.92 0.93 0.92 IN TR A -TE STE R M E A S U R E M E N T S V A R IA T IO N - R A N G E F R E Q U E N C Y D IS T R IB U T IO N 10- 9 - 7 — 5 6 - Z 3 5 —s £ *- al i l i l i i y ■ TESTER 1 □ TESTER 2 □ TESTER 3 IN II I 0 . 0 l 0 . 1 l 0 . 2 l 0 . 3 l 0 . 4 l 0 . 5 l 0 . 6 l 0 . 7 l 0 . 8 l 0 . 9 l 1 . 0 l 1 . 1 h . 2 h . 3 l 1 . 4 l 1 . 5 h . 6 h . 7 h . 8 h . 9 l 2 . 0 l 2 . 1 l 2 . 2 l 2 . 3 l 2 . 4 l 2 . 5 l 2 . 6 l 2 . 7 l 2 . 8 l C EN TIM ETER S TABLE 1: INTRA-TESTER VARIATION Tester Greatest Measurement Least Measurement Average Range Variation Within a Variation Within a of Variation (cm) Subject Over 4 Trials (cm) Subject Over 4 Trials (cm) 36 subjects 1 2.00 0.10 0.93 2 2.20 0.00 0.81 3 2.70 0.30 1.19 Mean: 0.98 TABLE 3 INTER-TESTER CORRELATIONS Tester Correlation Coefficient (r) 1 and 2 0.96 1 and 3 0.96 2 and 3 0.96 b eco m e m ore p ro m in en t aro u n d the ankle. These factors could affect the cir­ cum ference o f the ankle and influence th e m e a su rem e n t. R e co m m en d a tio n s w ere m ade by Tatro-A dam s et al. (1995) fo r further studies to establish the relia­ b ility o f the fig u re -o f-e ig h t m eth o d obtained at jo in t angles other than neutral dorsiflexion. T he purpose o f this study was to test the intra-tester and inter-tester reliability o f the figure-of-eight tape m ethod of ankle m easurem ent w ith the foot hanging free from a long-sitting position. METHOD T hirty-six m ale subjects from the fac­ ulty o f A llied H ealth Sciences (K uw ait U niversity) w ere recruited for this study. N one o f the subjects had sustained an ankle injury in the tw o m onths p rior to testin g . T he testin g p ro to c o l was described to each subject and each was asked to sign a consent form p rior to the beginning o f the study. A retractable plastic tape m easure was used to m easure the left or right ankle o f each subject (dom inant side). T he subject w as seated in a long sitting position w ith both feet beyond the end o f the plinth to the level o f the m id-calf. The ankle girth w as m ea­ sured w ith the foot hanging free, w ithout any active m uscle contraction occurring. The protocol used by E sterson (1979) w as follow ed for all m easurem ents. A fter m arking the landm arks w ith a skin pencil the tape m easure was w rapped around the ankle in the follow ing w ay (see Figure 1). 1. T he beginning o f the tape w as placed on the tibialis anterior tendon at the level o f the lateral m alleolus. 2. The tape was drawn m edially and placed ju st distal to the tuberosity o f the navicu­ lar. 3. The tape was pulled across the arch and up ju st proxim al to the base o f the fifth m etatarsal. 4. T he tape was pulled across the tibialis anterior tendon. 5. The tape was continued around the ankle join t ju st distal to the distal tip o f the m edial m alleolus. 6. The tape w as pulled across the Achilles tendon. 7. T he tape was placed ju st distal to the distal tip o f the lateral m alleolus. 8. The m easurem ent w as finished at the point at w hich it crosses the start o f the tape. The procedure was repeated four tim es by three testers giving a total o f tw elve trials per subject. The subject sequence w as determ ined by random assignm ent. T he recorder o f each trial m easurem ent w as blind to the previous m easurem ent. SPSS softw are was used to calculate the SA J o u r n a l o f P h y s io th e r a p y 1998 V o l 54 No 1 15 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) Intraclass Correlation Coefficients (ICCs) to assess the degree o f reliability o f the intra-tester and inter-tester m easurem ents. RESULTS The findings o f this study indicated that intra-tester m ea­ surem ent variations w ithin a subject over four trials ranged from 0.0 cm to 2.7 cm (Figure 2). Figure 2 illustrates that 64% show ed a variation o f less than 1cm. The average range o f the variation for each o f the three testers was 0.93 cm , 0.81 cm and 1.19 cm, w ith a m ean range fo r all three testers o f 0.98 cm (Table 1). The intra-tester correlation coefficient ranged b etw een 0.91 and 0.98 (Table 2). T he correlation coefficient b etw een testers was 0.96 (Table 3). DISCUSSION T his study is based on the recom m endations m ade by Tatro- A dam s et al. (1995) in a previous reliability study o f the fig- ure-of-eight tape m ethod o f ankle size assessm ent. The m ethodology in this study was largely based on that used by these authors. H ow ever, particular care was taken to obtain the m easurem ents with the foot in a relaxed position so that no m uscle contraction w ould occur, i.e. the foot was hanging free over the edge o f the plinth with the person in long sitting. This was in contrast to the above m entioned study w here the foot was held in neutral dorsiflexion. T he results o f this study agree with the figures obtained by Tatro-A dam s et al. (1995). H ow ever, our reliability scores are slightly different (0.96 versus 0.98) to the ones obtained by them. T hese results still indicate a very good intra- and inter-tester reliability. A p ossi­ ble explanation for this difference m ight be that the testers we used, although practising physiotherapists, had no previous experience w ith this technique. A m inim al instruction session (one hour) was provided before the study took place. The use o f m ore experienced testers could probably increase the reliability further. O nce the bony landm arks are indicated the technique is easy to perform in a tim e-efficient way. A s indicated by E sterson (1979) and Tatro-A dam s et al. (1995) the figure-of-eight tech­ nique has a higher validity than o ther circum ference m easures. In the figure-of-eight m easuring m ethod the tape crosses the injured structures, i.e. around the m alleoli and ventral side o f the foot. H ow ever, the m ethod can not differentiate betw een effusion and oedem a (intra- and extra-capsular swelling) where more com pli­ cated measures are required. M easurem ents with the foot in dorsi­ flexion at ninety degrees are not always possible due to pain and lim itations in range o f m otion. Also, m uscle contractions and ten­ don tension could ham per accurate m easurements. It is therefore recom m ended that measurements o f ankle size should preferably be done with the foot hanging free over the plinth’s end. Our results indicate that the figure-of-eight tape m ethod is a highly reli­ able m ethod o f measuring ankle size in healthy subjects. Further research should concentrate on reliability studies in a clinical set­ ting. Also, validity studies and com parative trials with other exist­ ing circumferencial methods are required to confirm the value of this technique as a clinical tool. CONCLUSION This study strongly supports the use o f the figure-of-eight tape m ethod as a reliable tool for the assessm ent o f ankle size. It is recom m ended to obtain ankle m easurem ents in a relaxed h an g ­ ing position to avoid m uscle contraction and tendon m ovem ents. This m ethod is easily learnt and has a potential as a tool fo r clin­ ical assessm ent and treatm ent planning and progress. Further research should be carried out to confirm the reliability o f the m easurem ent tool in a clinical setting. ACKNOWLEDGEMENTS The authors thank M r G. Bevan for his help with the statistical analysis and o f Dr. P. Rowe for reviewing this manuscript. REFERENCES Airaksinen O, Partanen K, Kolari P & Soimakallio S, 1991 Intermittent Pneumatic Compression Therapy in Post-traumatic Lower Limb Oedema: Computed Tomography and Clinical Measurements. Archives o f Physical Medicine and Rehabilitation, 72: 667-670. Esterson PS, 1979 Measurements of ankle joint swelling using a figure- of eight. Journal o f Orthopedic and Sports Physical Therapy, 1: 51-52. Nilsson S & Bjerknes-Haugen G, 1981 Volumetry in the evaluation of swelling in the ankle and foot. Journal o f Oslo City Hospital, 31: 11-15. Peterson L & Renstrom P, 1986 Sports injuries: their prevention and treatment. 2nd edition, pp 207: Dunitz Company, London. Stranden E & Myhre H, 1981 The local oedema following operations follow limb atherosclerosis(abstract). Acta Chirurgica Scandinavica, Suppl 506: 77. Tatro-Adams D, Forrester Me Gann S & Carbone W, 1995 Reliability of the Figure-of-Eight method of Ankle Measurement. Journal o f Orthopedic and Sports Physical Therapy, 22: 161-163. QUALIFIED PHYSIOTHERAPISTS ARE IN DEM AND IN: CA N A D A , NEW ZEALAND AND A U STRA LIA If you are interested in m oving ahead, we at Four Corners Em igration are specialists in Personal and Business M igration. Our international team o f experts w ill guide you through the com plex and constantly changing im m igration regulations. A llo w one o f our consultants to inform you of the different packages we offer. We provide the most com prehensive advice and assistance on em igrating to the country o f yo ur choice. We consult th ro u g h o u t South Africa. FourCorners e m i g r a t i o n Registered Migration Agent No. 89880 fourcorners@ icon.co.za Tel (021) 450 130 16 SA J o u r n a l o f P h y s io th e r a p y 1998 V o l 54 No 1 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) mailto:fourcorners@icon.co.za