Navicular Drop Test

Original Editor - Evan Thomas

Top Contributors - Evan Thomas, Admin, Manisha Shrestha, Kim Jackson, 127.0.0.1, Tony Lowe, Oyemi Sillo, Kai A. Sigel and WikiSysop

Purpose

The Navicular Drop Test (NDT) was first described by Brody in 1982 as a means of quantifying the amount of foot pronation in runners. It is the one of the static foot assessment tool and is intended to represent the sagittal plane displacement of the navicular tuberosity from a neutral position i.e. Subtalar joint neutral to a relaxed position in standing (Fig. 1).

Technique

Position the patient in standing so there is full weight-bearing through the lower extremity and ensure the foot is in the subtalar joint neutral position (“talar head congruent”). Mark the most prominent part of the navicular tuberosity and measure its distance from the supporting surface (floor or step). Ask the patient to relax and then measure the amount of sagittal plane excursion of the navicular with a ruler (Fig. 1). Alternatively, the test can also be performed in reverse, i.e. measuring from relaxed position up to talar neutral in standing postion. Many clinicians also choose to perform this test by marking the start and end position of the navicular on an index card placed along the inside of the foot and then measure the change with a ruler.

Figure 1. Measurement of navicular drop. The height of the navicular tuberosity is measured in neutral (A) and relaxed (B) stance positions, and the amount of excursion is measured. Image from Menz 1998.

Navicular Drop Test video provided by Clinically Relevant

Evidence

Table 1. NDT Values

Supinated foot	Neutral foot	Pronated foot
	6-8mm	≥10-15mm
<5mm	5-9mm	>9mm

Table 2. Measurement of navicular height in standing

Study	Population	Inter-rater reliability (ICC)	Intra-rater reliability (ICC)
Sell et al 1994	---	0.87-0.96	0.92-0.95
Shultz et al 2006	Healthy	0.56-0.67	0.91-0.97
Deng et al 2010	Healthy	0.83-0.95	0.83-0.95
Ben Langley et al 2016	Healthy		0.40

Table 3. Performance of the NDT

Study	Population	Inter-rater reliability (ICC)	Intra-rater reliability (ICC)	Sensitivity	Specificity
Mueller et al 1993	Healthy	0.78-0.83	---
Sell et al 1994	---	0.73	0.83
Shrader et al 2005	Rheumatoid Arthritis	0.85-0.97	0.90-0.98
Aboelnasr EA et al 2019	6-12 years School going children		0.98	88.1%	99.5%

 Foot length had a significant influence on the navicular drop in both men (p < 0.001) and women (p = 0.015), whereas no significant effect was found of age (p = 0.27) or BMI (p = 0.88). Per 10 mm increase in foot length, the navicular drop increased by 0.40 mm for males and 0.31 mm for females. 

Clinical Relevance

The function and structure of the medial longitudinal arch (MLA) of the foot has been proposed as a risk factor for developing injuries which is determined by the navicular position.

Increased navicular drop (ND) leads to the low MLA which has been determined to be a risk factors

• for sustaining injuries among novice runners exhibiting more knee pain, patellar tendinitis and plantar fasciitis 
• developing exercise related lower leg pain and patellofemoral pain syndrome.
• Headlee et al also found a positive NDT as being indicative of plantar intrinsic muscle fatigue.
• Excessive navicular drop has been reported in patients with a history of ACL tears and is thought to predispose individuals to shin splints and medial tibial stress syndrome.
  

Decreased navicular drop leading high arched reported a greater incidence of ankle injuries, stress fractures of the fifth metatarsal and iliotibialband friction syndrome in runners.

It may also help identify individuals who would benefit from prefabricated orthotics and modified activity in those with patellofemoral pain syndrome. NDT may also be of benefit assessing patients with overuse symptoms of the lower extremity.

It should also be noted that despite its relatively widespread use being simple and quick clinical measure, it lacks normative data from a large cohort of healthy individuals and conflicting opinion on the reliability of the measure. As with any clinical test, the results should interpreted with caution and informed clinical decisions should be made in light of the error associated with each technique. The NDT is only one component of an overall lower extremity evaluation and should be used in conjunction with other techniques.

The intricacies with navicular tuberosity and sub-talar joint palpation and percent weight bearing through the lower extremity are some factors for inconsistent reliabilty. So to addresses some of these issues other versions of the test exist, such as one involving a single leg stance relaxed position, the sit-to-stand navicular drop test (SSNDT) and Dynamic navicular drop ( DND).

Deng et al found no correlation between NDT and the sit-to-stand version (SSNDT), suggesting the static measures of navicular height change may not predict dynamic navicular motion during the gait cycle.