A Simple Test To Detect Spring Ligament Deficiency

Rupture or deficiency of the spring ligament is a pivotal step in the progression of the collapsing flatfoot deformity.^1-3 Significant changes in foot alignment will occur after spring ligament rupture which can be measured with standard X-rays. However, clinicians have traditionally relied upon magnetic resonance imaging (MRI) to confirm spring ligament ligament injury.^4,5

However, a simple, reliable clinical test may detect attenuation or rupture of the spring ligament in the human foot. Pasapula and colleagues developed and studied the “neutral heel lateral push test” and validated its direct relevance to spring ligament rupture in 21 cadaver specimens.⁶

One can perform the neutral heel lateral push test as follows:⁶

The examiner positions the patient’s ankle joint in full dorsiflexion and the subtalar joint in a neutral or slightly supinated position. Using the palm of one hand, the examiner stabilizes the lateral aspect of the calcaneus. Then, with the other hand, the examiner applies a lateral force against the medial aspect of the distal first metatarsal, pushing the forefoot laterally until reaching a firm end point.  In this test, one compares total transverse plane abduction of the forefoot on the rearfoot to the contralateral foot. A lack of firm end point may also suggest spring ligament rupture.

Pasapula and coworkers verified in their cadaver study that with sectioning of the spring ligament, significant lateral translation of the forefoot on the rearfoot occurs with the neutral heel lateral push test.⁶ X-rays confirmed that this test isolates motion primarily to the talonavicular joint which is normally restrained by the spring ligament (see photo immediately above). Pasapula and co-workers found that, with firm pressure, a lateral translation of 15 to 20 mm of the forefoot occurred with spring ligament sectioning. On the contrary, with sectioning of either the tibialis posterior tendon or the flexor digitorum longus tendon, no significant change of excursion of the forefoot was detected with this test. In particular, isolated sectioning of the tibialis posterior tendon did not lead to lateral forefoot translation, verifying that loss of this tendon is not the driving force behind the adult acquired flatfoot deformity.^7-9

In a subsequent cadaver study, Pasapula and colleagues used the neutral heel lateral push test to measure the effectiveness of various surgical procedures to repair a ruptured spring ligament.¹⁰ In this study, they used a loading frame and showed lateral translation of less than 20 mm with an intact spring ligament, which increased to greater than 40−50 mm with spring ligament sectioning. Augmented surgical reconstruction of the spring ligament restored the lateral translation to less than 20 mm.¹⁰

The findings from these studies provided the impetus for Pasapula et al to develop a new classification system for the adult acquired flatfoot based upon integrity of the spring ligament.¹¹ Pasapula team have also published several other interesting studies linking spring ligament injury to ankle fracture with deltoid ligament rupture as well as hallux valgus and first ray insufficiency.^12,13

I have personally performed the neutral heel lateral push test on many patients with adult acquired flatfoot deformity. When comparing forefoot excursion to the contralateral, asymptomatic foot, this test consistently detects significant transverse plane instability of the midtarsal joint in Stage 2 thru Stage 4 deformity.¹⁴ Based upon the excellent studies by Pasapula and colleagues, we can be confident that the neutral heel lateral push test accurately detects rupture of the spring ligament.^4,10

Dr. Richie is an Adjunct Associate Professor within the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt University in Oakland, Calif. He is a Fellow and Past President of the American Academy of Podiatric Sports Medicine. Dr. Richie is a Fellow of the American College of Foot and Ankle Surgeons, and the American Academy of Podiatric Sports Medicine. Dr. Richie is the author of a new book titled "Pathomechanics of Common Foot Disorders," which is available from Springer at https://www.springer.com/us/book/9783030542009 .

References

1. Deland JT, de Asla RJ, Sung IH, Ernberg LA, Potter HG. Posterior tibial tendon insufficiency: which ligaments are involved?  Foot Ankle Int. 2005;26(6):427-435.

2. Williams G, Widnall J, Evans P, Platt S. Could failure of the SL complex be the driving force behind the development of the adult flatfoot deformity? J Foot Ankle Surg. 2014;53(2):152–155.

3. Myerson MS, Thordarson DB, Johnson JE, et al. Classification and nomenclature: progressive collapsing foot deformity. Foot Ankle Int. 2020;41(10):1271-1276.

4. Ellis SJ, Yu JC, Williams BR, Lee C, Chiu YL, Deland JT. New radiographic parameters assessing forefoot abduction in the adult acquired flatfoot deformity. Foot Ankle Int. 2009;30:1168–1176.

5. Balen PF, Helms CA. Association of posterior tibial tendon injury with spring ligament injury, sinus tarsi abnormality, and plantar fasciitis on MR imaging. AJR Am J Roentgenol. 2001;176(5):1137-1143.

6. Pasapula C, Devany A, Magan A, Memarzadeh A, Pasters V, Shariff S. Neutral heel lateral push test: the first clinical examination of SL integrity. The Foot. 2015;25:69–74.

7. Jennings M, Christensen J. The effects of sectioning the SL on rearfoot stability and posterior tibial tendon efficiency. J Foot Ankle Surg. 2008;47(3):219–224.

8. Reeck J, Felten N, McCormack AP, et al. Support of the talus: a biomechanical investigation of the contributions of the talonavicular and talocalcaneal joints, and the superomedial calcaneonavicular ligament. Foot Ankle Int. 1998;19(10):674-682.

9. Cifuentes-De la Portilla C, Larrainzar-Garijo R, Bayod J. Analysis of the main passive soft tissues associated with adult acquired flatfoot deformity development: a computational modeling approach. J Biomech. 2019;84:183–190.

10. Pasapula C, Devany A, Fischer NC, et al. The resistance to failure of spring ligament reconstruction. Foot 2017;33:29–34.

11. Pasapula C, Cutts S. Modern theory of the development of adult acquired flat foot and an updated spring ligament classification system. Clin Res Foot Ankle 2017;5:247.

12. Pasapula C, Kiliyanpilakkil B, Khan DZ, et al. Plantar fasciitis: talonavicular instability/spring ligament failure as the driving force behind it histological pathogenesis. Foot (Edinb). 2021;46:101703.

13. Pasapula C, Ali AMS, Kiliyanpilakkil B, et al. High incidence of spring ligament laxity in ankle fractures with complete deltoid ruptures and secondary first ray instability. Foot (Edinb). 2021;46:101720

14. Richie D. Biomechanics and orthotic treatment of the adult acquired flatfoot. Clin Podiatr Med Surg. 2020;37(1):71-89.