Does Fat Pad Atrophy Contribute To Metatarsalgia?

Metatarsalgia is a common foot disorder and is often associated with calluses. Fat pad atrophy is a possible etiology for metatarsalgia and its role within the pathogenesis of the condition is highly controversial.

With increased numbers of patients with metatarsalgia presenting to my office after other physicians have told them they have fat pad atrophy, I felt this topic would be a great discussion. It is apparent in my practice from patients’ comments that more often than not, other foot and ankle specialists are blaming fat pad atrophy for metatarsalgia when the source of the problem could be more biomechanical in nature.

There are numerous articles in the literature that discuss fat pad atrophy and its role in foot pain. Typically, the focus is on metatarsalgia or forefoot calluses, but authors have also discussed fat pad atrophy in relation to heel pain.¹ Despite the possible association of a reduction of the plantar fat pad with the increased plantar pressure of metatarsalgia, authors have not been able to confirm this observation.²

One thought is that a decreased thickness in the forefoot fat pad through atrophy can lead to an increase in pain or metatarsalgia. However, Waldecker performed a study that demonstrated that the structural feature or the thickness of the plantar fat pad does not contribute to the pathogenesis of metatarsalgia.³

Mickle and colleagues studied the thickness of the soft tissue under the metatarsal heads of individuals with toe deformities.⁴ They concluded that the thinning was due to atrophy of the musculotendinous structures of the forefoot as opposed to fat pad atrophy. Dhinsa and coworkers report a case study in which the use of collagen injections for the treatment of metatarsalgia created a painful mass that required surgical excision.⁵

In their 2015 review, Dalal and colleagues looked to assess whether fat pad atrophy contributes to metatarsalgia and acknowledged that studies support both sides of this debate.⁶ The authors conclude that while there is not fad pad atrophy in patients with metatarsalgia, the fat pad is migrating and dislocating secondary to digital deformities in this patient population.

As practitioners who specialize in foot and ankle conditions, we should spend more time evaluating patients with metatarsalgia in order to look for causes other than fat pad atrophy. I have had success in educating patients on making changes to their shoe gear as well as making alterations in their gait, which has improved their forefoot pain. Rather than blame their symptoms on loss or atrophy of the fat pad due to the aging process, I would advise looking for other etiologies.

References

1. Resnick RB, Hudgins LC, Buschmann WR, Kummer FJ, Jahss MH. Analysis of the heel pad fat in rheumatoid arthritis. Foot Ankle Int. 1999;20(8):481-4.

2. Waldecker U, Lehr HA. Is there histomorphological evidence of plantar metatarsal fat pad atrophy in patients with diabetes? J Foot Ankle Surg. 2009;48(6):648-52

3. Waldecker U. Plantar fat pad atrophy: a cause of metatarsalgia? J Foot Ankle Surg. 2001;40(1):21-7.

4. Mickle KJ, Munro BJ, Lord SR, Menz HB, Steele JR. Soft tissue thickness under the metatarsal heads is reduced in older people with toe deformities. J Ortho Res. 2011;29(7):1042-6.

5. Dhinsa BS, Bowman N, Morar Y, et al. The use of collagen injections in the treatment of metatarsalgia: a case report. J Foot Ankle Surg. 2010;49(6):565.e5-7.

6. Dalal S, Widgerow AD, Evans GR. The plantar fat pad and the diabetic foot--a review. Int Wound J. 2015;12(6):636-40.