Plantar Calcaneal Spurs: Is Surgery Necessary?
The etiology of heel pain is quite varied. First described by Wood in 1812, the most common cause is thought to be plantar fasciitis. This is typically marked by focal tenderness to any component of the aponeurosis but most frequently at the proximal medial insertion of the plantar aponeurosis.1
Many symptomatic patients with plantar fasciitis demonstrate plantar heel spurs (traction enthesopathies) of the os calcis. One may best appreciate this shelf of exostosis on the lateral and lateral oblique views of standard radiographic studies.2 On rare occasions, fracture of this spur has been documented in the absence of obvious trauma.3 Frequently, clinicians may also see a lateral view Achilles tendon exostosis at the posterior tuberosity. However, these calcaneal spur formations, particularly the plantar shelf, are also present among patients with no active or prior history of pain. Is the plantar calcaneal spur the culprit or merely an innocent bystander?
Be aware that one may mistakenly attribute plantar heel spur formation to excess tension solely from the aponeurosis or fascia. In reality, it is the intrinsic plantar muscles that primarily serve as attachments to the apex of this spur. Researchers have found that the flexor digitorum brevis, as well as the quadratus plantae and the abductor hallucis, arise from this structure.4-6 The abductor digiti minimi remains lateral to the spur attachment and is non-contributory.
The plantar fascia attaches inferiorly or below the calcaneal processes or tubercles. The central fascial band is attached to the larger medial plantar tubercle, plantar and slightly posterior to the origin of the FHB. Proximally, the entire aponeurosis sends fibers to blend coherently with the Achilles tendon in the form of a “mesh” at the inferior calcaneus and remains plantar to the spur as a “sling.”4 Theoretically, poor foot mechanics invoking greater intrinsic muscle activity can lead to excessive traction at the tubercle.7 Over time, calcification of the periostitis allows radiographic visualization of the spur.
Initially, inferior calcaneal spurs can appear ill-defined and even irregular as with the seronegative arthridites. When clinicians see these spurs with gout, sclerosis and small erosions may accompany them.8 Spur formation can become well defined as one might see with degenerative joint disease, rheumatoid arthritis or advanced plantar fasciitis. The spurs can sometimes appear hook-shaped.
Are Heel Spurs Associated With Plantar Fasciitis?
Plantar fasciitis often responds to conservative care. In fact, most patients successfully respond to conservative treatment modalities for plantar fasciitis (fasciosis). Traditional strategies include oral steroid and non-steroidal regimens, local injections, strappings, complete or partial offloading, physical therapy, ice, stretching, orthotics, heel cups, night spints and improved shoe gear. Lapidus and Guidotti examined 364 feet and conservative therapy alleviated more than 90 percent of painful heels. When pain resolved in the face of plantar spurring, the spurs remained despite dissipation of the symptomatic inflammation.9
Also keep in mind that one may often see plantar heel spurs in feet that do not exhibit symptoms of plantar fasciitis. Barrett reported that 21 percent of 200 cadaveric feet contained heel spurs although this is a much larger proportion to those with plantar fasciitis in the general population.10 Rubin found that although 21 percent of his patients (125/461) possessed heel spurs, only 13 of them (10 percent with spurs) were symptomatic with heel pain.11 Although Shama, et. al., reported somewhat higher numbers with 39 percent being symptomatic (132 out of 1,000 spurs found), this was still well less than half of all spurs they examined.12 Tanz noted 16 asymptomatic heel spurs among 100 patients on lateral view plain film radiography.13 Therefore, many cases with plantar heel spurs are or become asymptomatic.
Conversely, one can safely state that a large percentage of patients with painful plantar fasciitis heel pain lack an inferior calcaneal spur. For example, O’Malley observed that 12 of 19 patients with symptomatic plantar fasciitis had no spur present.14