Figure of Eight Method of Measuring Ankle Joint Swelling

Original Editor - Christopher Eberley

Top Contributors - Christopher Eberley, Admin, Manisha Shrestha, Kim Jackson, Evan Thomas, WikiSysop, Fasuba Ayobami, Claire Knott, Wanda van Niekerk and Amanda Ager

Purpose

The purpose of this assessment technique is to evaluate ankle size and ankle joint swelling (edema).

The method of measuring joint swelling in a figure of 8 has the following advantages:

1. Being readily reproducible;
2. Measuring swelling at the various sites of ankle sprains;
3. Requires only a tape measure and marking pen, and
4. Feasible in a clinical setting, time-efficient, cost-effective, and easy to carry out.
   

Technique

Equipment needed

A retractable one-quarter inch wide plastic tape measure and a marking pen..

Patient position

Patients were positioned in long-sitting on a bed with the testing foot resting over the end. The knee may be slightly flexed over a bolster to allow for ease of measurement if needed. The ankle should ultimately be maintained in a position of neutral dorsiflexion.

Therapist position

At the end of the bed.

Once the patient has assumed their position on the plinth, the following standardized landmarks were marked with a pen prior to measurement:

a) the point midway over the anterior ankle between the tibialis anterior tendon and lateral malleolus,

b) the navicular tuberosity,

c) the base of the fifth metatarsal, and

d) the inferior tip of the medial malleolus.

The therapist placed the zero-point over the mark on the anterior aspect of the ankle and pulled the tape medially over the navicular tuberosity, and then infero-laterally across the medial arch to the proximal aspect of the base of the fifth metatarsal. The tape was then pulled superiorly and medially over the tarsal bones across the inferior aspect of the medial malleolus, and posterolaterally around the Achilles tendon over the distal lateral malleolus to finish at the zero point. At last, the measurement is recorded.

It is necessary to ensure that there was no indentation of soft tissue during measurement.

Evidence

In the laboratory,

• Intrarater and interrater reliability ranged from 0.98 to 0.99 (intraclass correlation coefficients [ICC]) for asymptomatic and swollen ankles. 
• Highly corelates (r>0.88) with the water displacement method for both injured and uninjured ankles,

In the clinical setting,

• Intrarater reliability was very high for the figure of eight with (Intraclass correlations coefficients [ICC] = 0.99).

• Inter-rater reliability was also very high (ICC > 0.99).
• The standard error of measurement (SEM) was small for all measurements: ±0.2cm for the figure of eight method.

The figure of eight measurement has also demonstrated criterion-related validity when compared to foot volumetry. The figure of eight method of measuring ankle joint swelling can be considered both valid and reliable.