Correlation between gastrocnemius tightness and heel pain severity in plantar fasciitis

Key Points

1. 33 subjects with plantar fasciitis completed a programme of ‘stretching’ based on the Alfredson protocol.
2. Gastrocnemius tightness and symptoms improved and there was a strong correlation between this tightness and severity of heel pain.
3. Study design and limitations prevent us from concluding that gastrocnemius tightness causes plantar fasciitis.

BACKGROUND & OBJECTIVE

Plantar fasciitis (PF) hurts deep down in your sole! It’s a challenging condition to treat with limited high-quality evidence to guide conservative management. Limited ankle dorsiflexion is commonly associated with PF (1), and traditionally stretches have been recommended as a treatment method. This study sought to determine the relationship between gastrocnemius tightness and symptom severity in PF.

Limited ankle dorsiflexion is commonly associated with plantar fasciitis.

Whether loss of ankle dorsiflexion is a cause of plantar fasciitis or the result of it, it does appear important to restore this range of motion.

METHODS

41 patients with PF were recruited who met the inclusion criteria. 33 of these completed the study and there were 8 that were lost to follow up. Participants were asked to complete a modified version of Alfredson’s eccentric protocol (2) which was only performed with the knee straight to target the gastrocnemius (see video). In addition to this a silicone gel insole was provided and patients were given a Strassburg Sock or night splint if their predominant symptom was pain on first steps in the morning.

ALFREDSON PROTOCOL

Outcome measures included gastrocnemius tightness (measured as the difference in ankle dorsiflexion range when the knee is flexed compared to straight), and visual analogue scale (VAS) for pain with first steps in the morning and worst pain in the previous week. These measures were recorded at baseline, 6 weeks, 3 months, 6 months and 9 months.

RESULTS

There were significant improvements in gastrocnemius tightness, first step pain and worst pain reported. Mean gastrocnemius tightness was 22o at baseline and reduced to 9o at final follow up. First step pain (VAS) reduced from a mean of 6.3 at baseline to 1.9 at final follow up, and worst pain score reduced from a mean of 7.6 to 2.5.

A strong and statistically significant correlation between gastrocnemius tightness and the severity of heel pain was observed (see Figure 1).

LIMITATIONS

The correlation between gastrocnemius tightness and symptom severity does not prove causation. In fact, it’s quite feasible that resolution of pain led to improved range, rather than improved range led to resolution of pain.

There was no blinding in this study design, and the lead author did all range of movement measurements so there is potential for bias. There was also no control group and a high rate of loss to follow up (approximately 20% of the initial cohort).

It appears that the ‘final follow up’ varied depending on when symptoms resolved. It isn’t clear how symptom resolution was defined or at what stage most patients reported it. These limitations raise the possibility that symptoms and range simply improved with time (rather than treatment).

CLINICAL IMPLICATIONS

Whether loss of ankle dorsiflexion is a cause of plantar fasciitis or the result of it, it does appear important to restore this range of motion. Dorsiflexion range is thought to be important for foot and ankle function and proprioception, so we can justify addressing it clinically.

Interestingly while this study advocates ‘stretches’, the eccentric protocol used is more of a loading programme and doesn’t employ prolonged static stretches. There is some evidence for stretching programmes in PF (3), but recent research suggested slightly better outcomes with progressive loading (4).

We may expect to see more lasting increasing in range of movement when using an eccentric programme or loading in lengthened positions than with static stretches. We would also be more likely to gain calf strength with this approach which may improve foot and ankle function.

As ever an individualized approach is needed and a combination of progressive loading and stretching may be an option, especially if there is significant loss of dorsiflexion range or stretches prove effective in reducing symptoms. However, we’re far from having all the answers with plantar fasciitis and should be open to other treatment options such as orthoses.

+STUDY REFERENCE

Pearce C, Seow D and Lau B (2020) Correlation Between Gastrocnemius Tightness and Heel Pain Severity in Plantar Fasciitis. Foot & Ankle International, p.107110072095514.

SUPPORTING REFERENCE

1. Patel, A. and DiGiovanni, B., 2011. Association Between Plantar Fasciitis and Isolated Contracture of the Gastrocnemius. Foot & Ankle International, 32(1), pp.5-8.
2. Alfredson, H., Pietilä, T., Jonsson, P. and Lorentzon, R., 1998. Heavy-Load Eccentric Calf Muscle Training For the Treatment of Chronic Achilles Tendinosis. The American Journal of Sports Medicine, 26(3), pp.360-366.
3. Digiovanni, B., Nawoczenski, D., Malay, D., Graci, P., Williams, T., Wilding, G. and Baumhauer, J., 2006. Plantar Fascia-Specific Stretching Exercise Improves Outcomes in Patients with Chronic Plantar Fasciitis. The Journal of Bone & Joint Surgery, 88(8), pp.1775-1781.
4. Rathleff, M., Mølgaard, C., Fredberg, U., Kaalund, S., Andersen, K., Jensen, T., Aaskov, S. and Olesen, J., 2014. High-load strength training improves outcome in patients with plantar fasciitis: A randomized controlled trial with 12-month follow-up. Scandinavian Journal of Medicine & Science in Sports, 25(3), pp.e292- e300.